1.EClY 6522 ENGINEERING CHANGE NOTICE P.pa 1o'a/67531/metadc717854/...HNF-2155 Rev 0, All Sheets I NIA Design AuthorityICog Engineer Signature & Date 5. Date 2/11/99 8.Approval Designator

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9 Document Numbers Changed by this ECN 10.Related ECN No(s) (includes sheet no. and rev.)

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As-Found [ I Facilitate Const [I Const. Error/Omission [ I Design Error/Omission [I 14b. Justification Detai 1 s Item 1) now covered by SARP: Item 2 ) revised worst case leak rate allows us to demonstrate compliance with NFPA 69 for hydrogen at CSB: Item 3) new worst rate leak rate is acceptable for all situations: Iten 4) supports oxygen getting calculations of TI-40, allows CVDF to just measure cask temperature (by whatever means they chose), and allows maximum flexibility regarding minimum ambient temperature during helium fl11 operation: Item 5) provides maximum operating flexibility at CSB: and Item 6 ) completes formal documentation that the MCOiCSB designs meet the CSB SRIDs for hydrogen gas management within the CSB tubes. 15 Distribution (include See distribution sheet.

ID

. . . /Yb) G N U 9

1 li

A-7900-013-1

HNF-2155, Rev. 1

MCO Combustible Gas Management Leak Test Acceptance Criteria

D. L . Sherrell DE&S Hanford. I n c . , Richland, WA 99352 U . S . Department o f Energy Contract DE-AC06-96RL13200

EDT/ECN: 652276 UC: 510 Org Code: 2F300 Charge Code: 105355/BA040 B&R Code: EW7040000 Total Pages: b2, Key Words: Spent Nuclear Fuel Project , Mul t i -canis ter Overpack, MCO, leak t e s t c r i t e r i a , ANSI N14.5, Canister Storage Bui ld ing, CSB. helium b a c k f i l l , helium loss, hydrogen leakage, stagnant a i r , National F i re Protect ion Association, NFPA 69, Lower Flammable L i m i t , LFL

Abstract: Ex is t ing leak t e s t acceptance c r i t e r i a f o r mechanically sealed and weld sealed mul t i -canis ter overpacks (MCO) were evaluated t o ensure t h a t MCOs can be handled and stored i n stagnant a i r without compromising the Spent Nuclear Fuel Pro ject ’s overal l strategy t o prevent accumulation o f combustible gas mixtures w i th in MCO’s or w i th in t h e i r surroundings. The document concludes t h a t the integrated leak t e s t acceptance c r i t e r i a f o r mechanically sealed and weld sealed MCOs (1 x 10~%td cc/sec and 1 x 10~’std cc/sec. respect ively) are adequate t o meet a l l current and foreseeable needs o f the pro jec t , including capabi l i ty t o demonstrate compliance w i th the NFPA 69 Paragraph 3-3 requirement t o maintain hydrogen concentrations [wi th in the a i r atmosphere CSB tubes1 a t o r below 1 vol% ( i . e . , a t o r below 25% o f the LFL)

TRAOEMARK DISCLAIMER. Reference herein t o any specif ic commercial product, process, o r service by trade name, trademark. manufacturer. or otherwise. does not necessarily consti tute or imply i t s endorsement. recomnendation. or favoring by the United States Government or any agency thereof o r i t s contractors or subcontractors

Printed i n the United States o f America. To obtain copies o f t h l s document. contact Control Services. P 0 Box 950. Mailstop Hb-08. Richland WA 99352, Phone (509) 372-2420: Fax (509) 376-4989.

Document

Date Release StamD

Approved for Pub1 i c Re1 ease A-6400.073 (01/97) GEF321

(1) Document Number HNF-2155 RECORD OF REVISION

M u l t i -Canister Overpack Combustible Gas Management Leak Test Acceptance C r i t e r i a

CHANGE CONTROL RECORD

Page 1

(4) Description of Change - Replace. Add. and Delete Pages

( 7 ) I n i t i a l Release EOT# 623984 (2/11/98)

Released via ECN# 652276 (2 /11/99) . Completely replaces a l l pages o f HNF-2155 w i t h Rev 1 o f t h a t document. Revis ion 1: 1) el iminates ca l cu la t i ons f o r shipping casks. which are now covered by the SARP: 2) updates a l l ca l cu la t i ons and support ing bases, assumptions, e t c . , t o r e f l e c t t he new, reduced pressure now l i s t e d by t h e p r o j e c t databook f o r a sa fe ty basis MCO: 3) el iminates ca l cu la t i ons f o r nominal pressure MCOs. which are no longer necessary: 4) revises the minimum helium f i l l pressure and maximum helium f i l l MCO temperature t o ensure t h a t a l l MCOs w i l l r e t a i n a t l e a s t 30.3 gmol o f helium a f t e r 40 years o f storage ( t o support t h e oxygen g e t t e r i n g r e s u l t s o f HNF-SNF-TI-40. and t o provide maximum f l e x i b i l i t y f o r the CVDF hel ium b a c k - f i l l operat ion): 5) takes advantage o f t he reduced hydrogen leak rates associated w i t h t h e new sa fe ty basis pressure t o a l l ow f o r staging two mechanically sealed MCOs w i t h i n one tube: 6 ) based on the new. reduced leakage ra tes , provides formal ca l cu la t i ons t o show t h a t vented CSB tubes w i l l never reach 1 vo l% hydrogen (even f o r two worst case leakage MCOs): anc 7 ) revises a l l t e x t and hand ca l cu la t i ons , as necessary, t o r e f l e c t a l l o f t he above changes.

Author (5 ) cog.

Engr. DL Sher re l l 2/20/98

d for Release

( 6 ) Cog. Mgr Date

JR Frederickson 2/20/98

A-7320-005 (08/91) WEF168

HNF-2155 Rev 1

MULTI -CANISTER OVERPACK COMBUSTIBLE GAS MANAGEMENT LEAK TEST ACCEPTANCE CRITERIA

HNF-2155 Rev 1

MULTI -CANISTER OVERPACK COMBUSTIBLE GAS MANAGEMENT LEAK TEST ACCEPTANCE CRITERIA

TABLE OF CONTENTS

ACRONYMS/ABBREVIATIONS i i i

EXECUTIVE SUMMARY i v

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 .0

2 .0

PURPOSE . . . 1.1 SCOPE :

1.1.1 1 . 1 . 2

1 . . . . . . . . . . . . . . . . . . . . . . . . . Loss o f Hydrogen From CSB Tubes v i a Tube Vents . . . Replacement o f B a c k f i l l Gas A t CSB . . . . . . . . . Hydrogen Release t o MCO/Cask Assembly Dur ing Transport Operations . . . . . . . . . . . . . . . .

1.1.3 2

SUMMARY OF RE 2 . 1

2 . 2

2 . 3

2 . 4

OF RESULTS AND CONCLUSIONS . . . . . . . . . . . . . . . . . 2 . 1 RECOMMENDATIONS . . . . . . .

2 . 1 . 1 Recommendations For MCOS With' Mechanicai Seals 2 . 1 . 2 Recommendations For MCOs With Welded End Closul

2 . 2 RESULTS AN0 CONCLUSIONS FOR MECHANICALLY SEALED MCOs . 2 .2 .1 Helium Retent ion . . . . . . . . . . . . . . 2 .2 .2 Hydrogen I n CSB Tubes . . . . . . . . . . . .

2 . 3 RESULTS AND CONCLUSIONS FOR WELD SEALED MCOs . . . . . 2 . 3 . 1 Helium Retent ion . . . . . . . . . . . . . . 2 .3 .2 Hydrogen I n CSB Tubes . . . . . . . . . . . .

2 . 4 NATIONAL FIRE PROTECTION ASSOCIATION COMPLIANCE . . . .

SULTS AND CONCLUSIONS . . . . . . . . . . . . . . . . . RECOMMENDATIONS . . . . . . . 2 . 1 . 1 Recommendations For MCOS With' Mechanicai Seals 2 . 1 . 2 Recommendations For MCOs With Welded End Closul RESULTS AN0 CONCLUSIONS FOR MECHANICALLY SEALED MCOs . 2 .2 .1 Helium Retent ion . . . . . . . . . . . . . . 2 .2 .2 Hydrogen I n CSB Tubes . . . . . . . . . . . . RESULTS AND CONCLUSIONS FOR WELD SEALED MCOs . . . . . 2 . 3 . 1 Helium Retent ion . . . . . . . . . . . . . . 2 .3 .2 Hydrogen I n CSB Tubes . . . . . . . . . . . . NATIONAL FIRE PROTECTION ASSOCIATION COMPLIANCE . . . .

. . . .

. . . .

-es

2 . . . . . . . .

4

3 .0 ASSUMPTIONS 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 . 0 SOURCES 4.1 4 . 2 4 . 3 4 .4

4 . 5 4 . 6 4 . 7

COMBUSTIBLE GAS MANAGEMENT 'DEFINITIONS AND 'REQUIREMENTS '

LEAK RATE DEFINITIONS AND LEAK RATE CORRELATION EQUATIONS MCO GAS INVENTORIES

TEMPERATURES . . . . . . . . . . . . . . . . . . . . . . GAS PROPERTY DATA . . . . . . . . . . . . . . . . . . . BAROMETRIC DATA . . . . . . . . . . . . . . CSB STORAGE TUBE V O I D VOLUMES . . . . . . . . . . . . .

. . . MCO BACKFILL TEMPERATURE AND 'MCO~CSB TUBE OPERATING

5 5 5 5

7

5 .0 COMB1 JSTIBLE 5 .

GAS 1 FI

5

MANAGEMENT FUNCTIONS AND REQUIREMENTS

1.1 JNCTION: PRECLUDE COMBUSTIBLE MIXTURES INSIDE 'MCOS

Funct ional Requirement : Preclude Ai r Ingress 5 . 1 . 1 . 1 Implementation C r i t e r i a . . . . . . . .

5 . 1 . 1 . 1 . 1 Minimum Time To Mainta in P o s i t i v e 5 . 1 . 1 . 1 . 2 Type o f B a c k f i l l Gas . . . . . .

t o ' MCOS '

8 9 Pressure

. . . . . 10 10 10

5 . 1 . 1 . 1 . 3 Maximum B a c k f i l l Pressure . . . 5 . 1 . 1 . 1 . 4 Minimum B a c k f i l l Pressure . . .

. 1 . 2 NFPA 69 Paragraph 2 - 7 . 2 Compliance Status ,

5 .1 .2 .1 Non-Compliance wi th S p e c i f i c Requirement 5 . 1 . 2 . 2 NFPA 69 Paragraph 2 -7 .2 Equivalency , .

5 . 1 . 2 . 2 . 1 St rategy To Achieve NFPA 69 Paragraph 2 -7 .2 Equivalency . .

5 11 . . . . . s . . . . . . . . .

11 12

13

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HNF-2155 Rev 1

6.0

7 . 0

5.2

PREDICTION OF 6 . 1

CALCULATIONS 7 . 1

7 . 2

7.3

FUNCTION: PRECLUDE COMBUSTIBLE MIXTURES OUTSIDE MCOs . . . . . 13 5 . 2 . 1 Funct ional Requirement: L i m i t H, Release From MCOs . . 14

5 . 2 . 1 . 1 Implementation C r i t e r i a . . . . . . . . . . . . . 14 5 .2 .1 .1 .1 Acceptable H, Concentrat ion . . . . . . . . 14 5 .2 .1 .1 .2 Minimum Time l o Main ta in Acceptable H,

Concentrat ion . . . . . . . . . . . . . . . 14 5 .2 .2 NFPA 69 Paragraph 3-3 Compliance Status . . . . . . . 14

OPERATIONAL LEAKAGE FROM LEAK TEST RESULTS . . . . . . . . . . 15 LEAKAGE CORRELATION DEFINITIONS AND METHODOLOGY . . . . . . . . 15 6 . 1 . 1 Shortcomings Of The ANSI N14.5-1987 Approach . . . . 16 6 . 1 . 2 The Revised Approach I n ANSI N14.5-1997 D r a f t J . . . 17

. . . . . . . . . . . . . . . . . . . . 18 MCO OPERATING CDNDITIONS . . . . . . . . . . . . . . . . . . . 18 7 . 1 . 1 MCD Gas Temperatures . . . . . . . . . . . . . . . . 18 7 .1 .2 MCD Gas Inven to r ies . . . . . . . . . . . . . . . . . 18

Worst Case Gas Inventory For C a l c u l a t i n g Helium Loss . . . . . . . . . . . . . . . . . . 18

7 . 1 . 2 . 1 . 1 Minimum I n i t i a l B a c k f i l l Gas Quan t i t y . . 18 7 .1 .2 .1 .2 Minimum Required MCC Helium Inven to ry . . 19 7 . 1 . 2 . 1 . 3 Maximum Acceptable Helium Loss . . . . . . 20 7 .1 .2 .1 .4 Design Goal f o r Maximum Helium Loss . . . 20

7 . 1 . 2 . 2 Worst Case Gas Inventory For C a l c u l a t i n g Hydrogen Release . . . . . . . . . . . . . . . . . . . . . 21

7 . 1 . 3 . 1 Maximum Pressure For Helium Loss Ca lcu ia t i ons . . 21 7 . 1 . 3 . 2 Maximum Pressure For Hydrogen Release

7 . 1 . 2 . 1

7 . 1 . 3 MCO Operating Pressures . . . . . . . . . . . . 21

Ca lcu la t i ons . . . 21 DCCUMENTATION/VALIDATION OF FLOW CORRELATION CALCULATIONS . . . 21 . . . . . . . . . . .

7 . 2 . 1 ANSI N-14.5 D r a f t 1997 J Equations and Guidel ines . . 21 7 . 2 . 1 . 1 D e f i n i t i o n O f Symbols . . . . . . . . . . . . . . 22 7.2.1.2 Basic Flow Equations . . . . . . . . . . . 23 7 . 2 . 1 . 3 Hand C a l c u l a t i o n A t Reference Condi t ions . . . . 23 7 . 2 . 1 . 4 Hand Ca lcu la t i on A t Test Condi t ions . . . . . . . 24 7.2.1.5 Hand Ca lcu la t i on A t Operating Condi t ions . . . . 26

7 . 2 . 1 . 5 . 1 Helium Loss Ca lcu la t i ons . . . . . . . . . 26 7 . 2 . 1 . 5 . 2 Hydrogen Release Ca lcu la t i ons . . . . 28

MAXIMUM STEADY STATE HYDROGEN CONCENTRATION I N CSB TUBES . . . 31 7 . 3 . 1 D i l u t i o n by Baromet r i ca l l y Induced Breath ing . . . . 31

7 .3 .1 .1 Assumptions . . . . . . . . . . . . . . . . . . . 31 7 . 3 . 1 . 2 Basis For Air-Exchange Rate . . . . . . . . . . . 31 7 . 3 . 1 . 3 Ma te r ia l Balance Equations . . . . . . . . . . . 32

APPENDIX A: SPREAD SHEET CALCULATIONS 36

APPENDIX B : THE NFPA 69 EXPLOSION PREVENTION STANDARD . . . . . . . . . . . . . . 40

APPENDIX C: ALTERNATE CALCULATIONS 42

APPENDIX D: INDEPENDENT REVIEW 53

APPENDIX E : REFERENCES 55

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . .

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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HNF-2155 Rev I

ACRONYMS/ABBREVIATIONS

CSB Canis ter Storage B u i l d i n g CVDF Cold Vacuum Dry ing Faci 1 i t y DOE U . S . Department o f Energy LOC L i m i t i n g Oxidant Concentrat ion LFL Lower F1 ammabl e L i m i t MCO mu1 t i - c a n i s t e r overpack MHM MCO Hand1 i ng Machi ne NFPA Nat ional F i r e P ro tec t i on Associat ion p s l a absolute pressure, pounds per square i n c h p s i g gage pressure, pounds per square i n c h SNF Spent Nuclear Fuel

iii

HNF-2155 Rev I

EXECUTIVE SUMMARY

Leak t e s t acceptance c r i t e r i a f o r mechanical ly sealed and weld sealed m u l t i - c a n i s t e r overpacks (MCO) were evaluated t o ensure t h a t , i n t h e u n l i k e l y event t h e leak t e s t r e s u l t s f o r an MCO were t o approach e i t h e r o f those c r i t e r i a , i t cou ld s t i l l be handled and s to red i n stagnant a i r w i thout compromising t h e Spent Nuclear Fuel P r o j e c t ’ s o v e r a l l s t ra tegy t o prevent accumulation o f combustible gas mixtures w i t h i n MCOs or w i t h i n t h e i r surroundings. Note: w i t h t h e except ion o f t h e mechanical s e a l ’ s leak t e s t acceptance c r i t e r i o n i t s e l f (which i s evaluated by t h i s document), t h i s document does no t apply t o MCOs u n t i l they have been completely processed and acceptance t e s t e d a t t h e Cold Vacuum Drying F a c i l i t y (CVDF). Also no te t h a t t h i s document doesn’ t address re lease o f r a d i o l o g i c a l contaminat ion from MCOs.

Recommendations f o r Mechanical ly Sealed MCOs

MCOs should remain a t 1 X s t d cc/sec. This w i l l ensure: The i n t e g r a t e d leak t e s t acceptance c r i t e r i o n f o r mechanical ly sealed

t h a t a p o s i t i v e hel ium gage pressure would remain w i t h i n any mechanical ly sealed MCO f o r we l l over 40 years w i thout replenishment ;

t h a t it would take over 3 years f o r t h e hydrogen concent ra t ion t o reach 1 v o l % w i t h i n a sealed (no allowance f o r loss v i a t h e tube ’s vent p o r t ) s i n g l y occupied storage tube conta in ing a s a f e t y bas is pressure MCO w i t h mechanical seals (note t h a t t h e p a r t i c u l a r combination o f gas inventory and temperature requ i red t o produce t h e pressure used f o r t h i s leakage c a l c u l a t i o n i s no t expected t o occur f o r any MCO dur ing t h e f i r s t few years o f storage, nor f o r t h e m a j o r i t y o f MCOs dur ing up t o 40 years o f s to rage) :

t h a t i t would take over t e n months f o r t h e hydrogen concent ra t ion t o reach 1 vo l% w i t h i n a sealed storage tube conta in ing two s a f e t y bas is pressure MCOs w i t h mechanical sea ls ;

t h a t , based on b a r o m e t r i c a l l y induced a i r exchange alone (i . e . , no c r e d i t i s taken f o r volume expansion from thermal c y c l i n g o r f o r d i f f u s i o n ) . a vented CSB tube conta in ing t h e worst case MCO payload f o r hydrogen leakage (2 each, mechanical ly sealed, s a f e t y bas is pressure MCOs) w i l l never exceed 1 vo l% hydrogen (see s e c t i o n 7 . 3 ) ; and

t h a t , based on d i f f us i , on alone ( i . e . , no c r e d i t i s taken f o r b a r o m e t r i c a l l y induced a i r exchange o r thermal c y c l i n g ) , a vented CSB tube conta in ing the worst case MCO payload f o r hydrogen leakage (2 each. mechanical ly sealed, s a f e t y basis pressure MCOs) w i l l never exceed 1 v o l % hydrogen (see Appendix C ) .

Recommendat 1 ons f o r We1 d Sealed MCOs

welds was determined t o be adequate t o meet a l l cu r ren t and foreseeable needs of t h e p r o j e c t

The e x i s t i n g 1 X 1 0 ’ s t d cc/sec leak t e s t acceptance c r i t e r i o n f o r MCO

1v

HNF-2155 Rev 1

1.0 PURPOSE

The purpose of this document is to support the Spent Nuclear Fuel Project’s combustible gas management strategy while, at the same time. avoiding the need to impose any requirements for oxygen free atmospheres within storage tubes that contain multi-canister overpacks (MCO). In order to avoid inerting requirements it is necessary to establish and confirm leak test acceptance criteria for mechanically sealed and weld sealed MCOs that are adequate to ensure that, in the unlikely event the leak test results for any MCO were to approach either of those criteria, it could still be handled and stored in stagnant air without compromising the SNF Project’s overall strategy to prevent accumulation of combustible gas mixtures within MCOs or within their surroundings. To implement that strategy, this document: 1) establishes combustible gas management functions and minimum functional requirements for the MCO’s mechanical seals and closure weld(s): 2) establishes a maximum practical value for the minimum required initial MCO inert backfill gas pressure: and 3) based on items 1 and 2. establishes and confirms leak test acceptance criteria for the MCO’s mechanical seal and final closure weld(s)

1.1 SCOPE

The overall scope o f this document is limited to consideration of leak testing criteria that pertain directly to the above stated purpose(s). document does not address release o f radiological contamination from MCOs (i :e., it does not address the implications of a given leak test acceptance criterion with respect to the MCO’s radiological confinement function)

mechanically sealed, pressurized MCOs that have successfully undergone leak testing at the Cold Vacuum Drying Facility (CVDF) following completion of the CVDF process: and 2 ) from pressurized MCOs that have successfully undergone leak testing following completion of their final closure weld(s) at the Canister Storage Building (CSB). Any evaluation of MCO gas leakage prior to completion of the CVDF process is beyond the scope of this document.

lhis

The scope is further limited to evaluation of gas leakage: 1) from

1.1.1

Whereas Revision 0 o f this document did not quantitatively address (nor take credit for) loss o f hydrogen from tubes via the stagnant tube vents, section 7.3 of this revision (Revision 1) provides calculations to confirm that no vented CSB tube, regardless of its payload configuration, will ever exceed 1 vol% hydrogen. An alternate calculation has also been added (see Appendix C) to further substantiate the conclusions of section 7.3.

Loss o f Hydrogen From CSB Tubes v i a Tube Vents

1.1.2

are sampled at the CSB.

Replacement o f B a c k f i l l Gas A t CSB

This document does not address replacement of backfill gas for MCOs that

HNF-2155 Rev 1

1.1.3

As o f Revis ion 1, t h i s document no longer addresses hydrogen re lease from MCOs i n t o t h e MCO t r a n s p o r t a t i o n cask. Those c a l c u l a t i o n s a re now prov ided by t h e Sa fe ty Ana l y s i s Report f o r Packaging (Onsite) M u l t i - c a n i s t e r Overpack

Hydrogen Release t o MCOKask Assembly Dur ing Transport Operations

(HNF -SD-TP-SARP-017).

2.0 SUMMARY OF RESULTS AND CONCLUSIONS

2 . 1 RECOMMENDATIONS

developed i n sec t i on 4 . 0 . The f o l l o w i n g recommendations a re based on func t i ons and requirements

2.1.1 Recommendations For MCOs With Mechanical Seals

The i n t e g r a t e d l eak t e s t acceptance c r i t e r i o n f o r mechanical ly sealed MCOs should cont inue t o be s p e c i f i e d as 1 x s t d cc/sec. The above leak t e s t acceptance c r i t e r i o n i s reasonable i n l i g h t o f t h e Test Report For M u l t i p l e Can is te r Overpack Mechanical Closure Prototype Tes t i ng (WHC-SD-SNF TRP-018). The l a s t paragr tph o f s e c t i o n 3 . 2 i n t h a t r e p o r t s t a t e s t h a t t h e p ro to type mechanical seal . . . had a l eak r a t e o f 1 . 4 x 1 0 ~ ’ s t d - c d s . . . ” a t t h e MCO’s 132T maximum design temperature f o r CSB s torage opera t i ons .

2.1.2

The c u r r e n t i n t e g r a t e d l eak t e s t acceptance c r i t e r i o n f o r MCOs w i t h welded end c losures (1 x IF7 s t d cc/sec) should be re ta ined . Th is c r i t e r i o n i s reasonable f o r a welded c losu re and i s more than adequate t o meet a l l t h e f u n c t i o n a l requirements t h a t a re imposed i n sec t i on 5 . 0 . t o accommodate any foreseeable changes t o t h e func t i ona l requirements t h a t might be expected t o occur as t h e p r o j e c t evolves

Recommendations For MCOs With Welded End Closures

It i s a l s o adequate

2.2 RESULTS AND CONCLUSIONS FOR MECHANICALLY SEALED MCOs

2.2.1 Helium Retent ion

The recommended leak t e s t acceptance c r i t e r i o n f o r t h e MCO’s mechanica l ly sealed end c losu re (1 x 1 0 - ’ s t d cc/sec) w i l l ensure a p o s i t i v e he l ium gage pressure w i t h i n both nominal and sa fe ty bas is pressure MCOs f o r over 76 years . It w i l l a l s o ensure r e t e n t i o n o f t h e 30.3 gmol minimum hel ium inven to ry used t o c a l c u l a t e sa fe ty bas is oxygen concentrat ions (see sec t i on 5 .1 .1 .1 .4 ) f o r over 40 yea rs . Th is w i l l p rov ide an adequate design margin t o accommodate any changes t o requirements t h a t may occur as t h e p r o j e c t evolves

2

HNF-2155 Rev 1

2.2.2 Hydrogen I n CSB Tubes

Hydroqen Wi th in S i n q l y OccuDied. Un-Vented CSB Tubes

The c u r r e n t l eak t e s t acceptance c r i t e r i o n f o r t h e M C O ' s mechanica l ly sealed end c l o s u r e (1 x s t d cc/sec) w i l l ensure t h a t i t would t a k e over 3 years f o r t h e hydrogen concentrat ion t o reach 1 v o l t (25% o f i t s Lower Flammable L i m i t - - LFL) w i t h i n an un-vented. s i n g l y occupied s torage tube con ta in ing a s a f e t y bas i s pressure case MCO w i t h mechanical sea ls . Note t h a t t h e p a r t i c u l a r combination o f gas i nven to ry and temperature requ i red t o produce t h e pressure used f o r t h i s leakage c a l c u l a t i o n i s n o t expected t o occur f o r any MCO du r ing t h e f i r s t few years o f s torage, no r f o r t h e m a j o r i t y o f MCOs du r ing up t o 40 years o f s torage.

Hydroqen Wi th in Doubly OccuDied. Un-vented CSB Tubes

The c u r r e n t leak t e s t acceptance c r i t e r i o n f o r t h e M C O ' s mechanica l ly sealed end c losu re (1 x 1 0 ~ 5 s t d cc/sec) w i l l ensure t h a t it would t a k e over t e n months f o r t h e hydrogen concentrat ion t o reach 1 v o l % w i t h i n an un-vented s torage tube con ta in ing two s a f e t y bas i s pressure MCOs w i t h mechanical sea ls .

Hvdroqen Wi th in Vented CSB Tubes

Based on d i l u t i o n o f hydrogen v i a t h e a i r exchange t h a t accrues from barometr ic pressure v a r i a t i o n s a lone (i . e . , w i t h no a d d i t i o n a l al lowance f o r thermal c y c l i n g o r d i f f u s i o n ) , t h e cu r ren t leak t e s t acceptance c r i t e r i o n f o r t h e M C O ' s mechanical ly sealed end c losu re (1 x t h a t no vented CSB tube w i l l ever exceed 1 v o l % hydrogen, even i f i t conta ins two s a f e t y bas i s pressure MCOs w i t h mechanical seals (see sec t i on 7 .3 ) . Appendix C prov ides an a l t e r n a t e c a l c u l a t i o n t h a t reaches t h e same conclus ion. based on s t a t i c d i f f u s i o n alone, w i t h no al lowance f o r a i r exchange from barometr ic o r thermal c y c l i n g . I n view o f t h e f a c t t h a t bo th mechanisms (mass f l o w and s t a t i c d i f f u s i o n ) w i l l a c t u a l l y be a c t i v e a t t h e same t ime , t h e o v e r a l l conc lus ion i s t h a t no vented CSB tube w i l l ever reach 1 v o l % hydrogen unless i t conta ins an MCO w i t h a d e f e c t i v e seal o r breached w a l l , e t c . .

s t d cc/sec) w i l l ensure

2.3 RESULTS AND CONCLUSIONS FOR WELD SEALED MCOs

2 .3 .1 Helium Retent ion

(1 x pressure w i t h i n s a f e t y bas i s pressure case MCOs f o r thousands o f years. Th is means t h a t any MCO could con ta in dozens o f i n d i v i d u a l l y t e s t e d welds (as opposed t o a s i n g l e i n t e g r a t e d leak t e s t t o con f i rm 5 1 x s t d cc/sec) and s t i l l r e t a i n a p o s i t i v e he l ium gage pressure we l l beyond t h e p r o j e c t l i f e . The 1 x minimum hel ium inven to ry used t o c a l c u l a t e oxygen concentrat ions (see s e c t i o n 5 . 1 . 1 . 1 . 4 ) over t h e e n t i r e p r o j e c t l i f e . Th i s statement would be v a l i d , even i f an MCO conta ined more than seven i n d i v i d u a l l y t e s t e d welds t h a t almost f a i l e d t o meet t h e l eak t e s t s p e c i f i c a t i o n .

The e x i s t i n g l eak t e s t acceptance c r i t e r i o n f o r t h e welded MCO c l o s u r e s t d cc/sec) i s more than adequate t o r e t a i n a p o s i t i v e he l ium gage

s t d cc/sec c r i t e r i o n w i l l a l s o ensure r e t e n t i o n o f t h e 30.3 gmol

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2.3.2 Hydrogen I n CSB Tubes

Hydrogen i n Un-Vented CSB Tubes

welds i s adequate t o ma in ta in t h e hydrogen concentrat ion below 1 v o l % f o r over 100 years within a completely sealed s torage tube con ta in ing two s a f e t y bas i s pressure MCOs, each o f which almost f a i l e d t h e leak t e s t .

Hydrogen I n Vented Storacle Tubes

t h a t accrues from barometr ic pressure v a r i a t i o n s alone (i . e . , w i t h no a d d i t i o n a l al lowance f o r thermal c y c l i n g o r d i f f u s i o n ) , t h e c u r r e n t l eak t e s t acceptance c r i t e r i o n f o r MCO welds (1 x lO~’ s t d cc i sec ) w i l l ensure t h a t no vented CSB tube w i l l ever reach 1 v o l % hydrogen (see sec t i on 7 . 3 ) .

The e x i s t i n g 1 x l O ~ ’ s t d cc/sec leak t e s t acceptance c r i t e r i o n f o r MCO

Based on d i l u t i o n o f hydrogen w i t h i n vented CSB tubes by a i r exchange

2.4 NATIONAL FIRE PROTECTION ASSOCIATION COMPLIANCE

Appendix B prov ides a summary o f t h e Nat ional F i r e P ro tec t i on Assoc ia t i on (NFPA) Standard on Explos ion Prevent ion Systems (NFPA 69) . along w i t h a general d i scuss ion o f i t s a p p l i c a t i o n t o t h e MCO. Sect ion 5 . 2 . 2 o f t h i s document descr ibes t h e p r o j e c t ’ s s ta tus w i t h respect t o Paragraph 3 -3 o f NFPA 69 and concludes, based on t h e hydrogen leakage c a l c u l a t i o n r e s u l t s o f sec t i on 7 . 2 (summarized on t h e t h i r d sheet o f Appendix A) and t h e subsequent atmospheric a i r exchange c a l c u l a t i o n s o f sec t i on 7.3 (and Appendix C ) , t h a t a l l MCO handl ing, s tag ing , and s torage operat ions c u r r e n t l y env is ioned f o r t h e CSB can be performed i n compliance wi th t h e requirements o f NFPA 69,Paragraph 3 - 3 . See s e c t i o n 5 . 2 . 1 f o r a d e s c r i p t i o n o f t h e p r o j e c t ’ s s ta tus w i t h respect t o NFPA 69 Paragraph 2 -7 .2 , which app l i es t o cond i t i ons w i t h i n MCOs.

3.0 ASSUMPTIONS

A l l assumptions a re i d e n t i f i e d and j u s t i f i e d as they a r e app l i ed

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4.0 SOURCES

4.1 COMBUSTIBLE GAS MANAGEMENT DEFINITIONS AND REQUIREMENTS

Sec t ion 12 .1 .1 ( F i r e P ro tec t i on , Management, Program P o l i c y ) o f t h e CSB's Standards/Requi rements I d e n t i f i c a t i o n Document (HNF-SD-SNF-RD-007) invokes a1 1 app l i cab le NFPA codes and standards, l i s t i n g t h e requirement source as paragraph 5 . c o f DOE 5480.7A ( F i r e P r o t e c t i o n ) . Because MCOs a r e expected t o con ta in hydrogen gas, t h e o v e r a l l process design ( i n c l u d i n g , bu t n o t l i m i t e d t o , t h e des ign o f t h e MCO i t s e l f ) i s requ i red t o comply w i t h a l l app l i cab le sec t i ons o f NFPA 69 (Standard on Explos ion Prevent ion Systems). See Appendix B o f t h i s document f o r a summary d e s c r i p t i o n o f NFPA 69. along wi th a general d iscuss ion o f i t s a p p l i c a t i o n t o t h e MCO.

Add i t i ona l requirements f o r eva lua t i on o f bounding case MCOs a r e taken from NRC Regulatory Guide 1 .7 (Contro l o f Combust7ble Gas Concentrat ions i n Containment Fo l l ow ing a Loss-of-Coolant Acc iden t ) .

4.2 LEAK RATE DEFINITIONS AND LEAK RATE CORRELATION EQUATIONS

Sect ion 4.13 o f t h e cu r ren t MCO performance s p e c i f i c a t i o n (HNF-S-0426) requ i res a l l MCO seals t o be " . . . l e a k a g e r a t e t e s t a b l e i n accordance w i t h ANSI N14.5. . . . " Therefore a l l leak r a t e d e f i n i t i o n s and leak r a t e c o r r e l a t i o n equations used i n t h i s document a re taken from t h e American Na t iona l Standard f o r Rad ioac t i ve M a t e r i a l s - - leakage t e s t s on packages f o r shipment (ANSI N14.5). See s e c t i o n 6 .1 , below, f o r a d d i t i o n a l d e t a i l

4.3 MCO GAS INVENTORIES

Table 4 - 1 o f t h e Spent Nuclear f u e l Product S p e c i f i c a t i o n (HNF-SD-SNF- OCD-001) l i s t s t h e maximum b a c k f i l l gas i nven to ry o f an MCO as 41.3 gmol, based on a 500 L minimum MCO vo id volume t h a t has been b a c k f i l l e d t o a maximum pressure o f 12 .5 p s i g (27.2 ps ia - - 1.85 atm) a t a minimum MCO/Cask assembly temperature o f O'C. Note t h a t t h i s corresponds t o a O'C i n t e r n a l gas temperature because a zero power MCO i s conservat ive f o r c a l c u l a t i o n o f t h e maximum b a c k f i l l gas i nven to ry . f o r b a c k f i l l gas loss c a l c u l a t i o n s i s developed i n sec t i on 7 . 1 . 2 . 1 . 1 .

The 65.5 gmol hydrogen inven to ry used f o r a l l hydrogen re lease and b a c k f i l l gas l o s s c a l c u l a t i o n s i s based on a t o t a l gas i nven to ry (95 .8 gmol) t h a t corresponds t o t h e 5 .3 atm (absolute) maximum pressure reached i n t h e p l o t on page K - 1 7 o f HNF-SD-TI-40. Rev. 3 (MCO I n t e r n a l Gas Composition and Pressure Dur ing I n t e r i m Storage) , g iven t h e 30.3 gmol b a c k f i l l gas i nven to ry upon which t h a t p l o t i s based. Note t h a t t h i s approach conserva t i ve l y takes a l l o the r gases (oxygen. f i s s i o n gas, o r any o the r gas t h a t may be inc luded i n t h e 95.8 gmol t o t a l ) as hydrogen.

The minimum b a c k f i l l gas i nven to ry t o be used

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4.4 MCO BACKFILL TEMPERATURE AND MCOKSB TUBE OPERATING TEMPERATURES

The MCO gas temperature range (OT minimum t o 42°C maximum) used f o r c a l c u l a t j o n of b a c k f i l l gas q u a n t i t i e s i s based on: 1) t h e minimum and maximum MCO Transport Cask temperatures (OcC minimum, 25T maximum) al lowed f o r performance o f t h e f i n a l MCO b a c k - f i l l operat ion a t t h e CVDF - - see s e c t i o n 2 4 . 2 . 2 o f t h e Spent Nuclear Fuel P r o j e c t Product S p e c i f i c a t i o n (HNF-SD-OCD- 001, Rev. 1): 2) t h e 42°C average fue l temperature shown f o r a 25'C Transport Cask temperature on F igure 5-810 o f the Safe ty Analysis Report f o r Packaging (Onsite) M u l t i - C a n i s t e r Overpack (HNF-SO-TP-017). and 3 ) t h e assumption t h a t t h e r e w i l l be no temperature d i f f e r e n t i a l between t h e MCO i n t e r i o r and t h e MCO Transport Cask f o r a zero power MCO (which i s conservat ive f o r t h e maximum b a c k f i l l i nventory c a l c u l a t i o n )

The MCO gas temperature used f o r hydrogen release and b a c k f i l l gas loss c a l c u l a t i o n s i s taken as the average fue l temperature (64°C) t h a t corresponds t o t h e same p o i n t i n t ime (40 years ou t ) t h a t t h e maximum pressure i s reached i n t h e p l o t on page K-17 o f HNF-SD-TI-40, Rev. 3 (MCU Interna7 Gas Compos7tion and Pressure Dur ing I n t e r i m Storage). The corresponding CSB storage tube gas temperature (64°C) was conserva t ive ly assumed t o be equal t o t h e MCO gas temperature. That assumption i s conservat ive because it r e s u l t s i n a shor te r t ime f o r t h e tube t o reach 1 v o l t hydrogen than would be t h e case i f t h e c a l c u l a t i o n were based on t h e actual storage tube gas temperature (something l e s s than t h e MCO gas temperature).

t h a t t h e MCO's i n t e r n a l pressure never goes negat ive was conserva t ive ly taken as t h e lowest ambient temperature on record (-23°F. i . e . , -31'C). per Table 3 .9 o f t h e Hanford S i t e C l imato log ica l Data Sumary 1996 With H i s t o r i c a l Data

The minimum MCO operat ing temperature used f o r t h e c a l c u l a t i o n t o conf i rm

(PNNL-11471).

4.5 GAS PROPERTY DATA

Gas p roper ty data were obtained from: ANSI N-14.5 D r a f t 1997 J , Table 5 .1 : from Fundamentals o f Momentum, Heat and Mass Transfer, Appendix I (Welty, e t . a l . , 1969): from t h e CRC Handbook o f Chemistry and Physics (49 th E d i t i o n ) , and from page 208 o f t h e Scott Spec ia l ty Gases ca ta log (Scot t Environmental Technology I n c . . 1985)

4.6 BAROMETRIC DATA

most r e c e n t l y been documented i n Barometric Pressure Var ia t ions (WHC-EP-0651). Table 6 o f t h a t repor t provides minimum, average, and maximum i n t e g r a t e d shor t - te rm data f o r per iods from one hour t o one year .

Local barometr ic e f f e c t s (used f o r c a l c u l a t i o n s i n s e c t i o n 7 . 3 . 1 ) have

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4.7 CSB STORAGE TUBE VOID VOLUMES

Sect ion 1 3 . 2 o f t h e Canister Storage B u i l d i n g Process Technical Manual (HNF-1719, D r a f t Rev D) provides storage tube v o i d volume est imates f o r var ious payload c o n f i g u r a t i o n s . Because t h a t document does no t a c t u a l l y address t h e worst case payload c o n f i g u r a t i o n used f o r t h e hydrogen concent ra t ion c a l c u l a t i o n s i n sec t ion 7 . 3 o f t h i s document (two mechanical ly sealed MCOs w i t h i n a s i n g l e t u b e ) , t h e f o l l o w i n g i n d i v i d u a l volumes were obtained from t h e net volumes l i s t e d i n Table 13-2 o f t h e d r a f t document:

Empty Storage Tube Void Volume (Less Plug) - - - - - - - - - - - - - - - - 4460 1

Lower Impact Absorber Displacement Volume - - - - - - - - - - - - - - - - - 280 1

Intermedi a t e Impact Absorber Displacement Vol ume - - - - - - - - - - 90 L

MCO Displacement Volume Without Welded Cap - - - - - - - - - - - - - - - - 1210 L

MCO Displacement Volume With Welded Cap - - - - - - - - - - - - - - - - - - - 1260 1

Storage Tube Sh ie ld Plug Displacement Volume - - - l i s t e d as "TBD" 1

The d r a f t techn ica l manual l i s t s t h e s h i e l d p l u g displacement volume as "TBD" because t h e s h i e l d p l u g design had not been f i n a l i z e d a t t h a t p o i n t i n t ime. However. t h a t design has now been f i n a l i z e d on H-2-120918. Rev 0 (Mechanical CSB Standard Tube P l u g Assembly):

Length o f In-Tube P o r t i o n . . . . . . . . . . . . . . . . . . . . . 41 inches, o r 104 cm Diameter o f In-Tube P o r t i o n - - - - - - - - - - - - - - - - - - 26 inches, o r 66 cm

The approximate displacement volume o f t h e s h i e l d p lug i s t h e r e f o r e :

n(66 /2 cm)' x 97 cm = 105.633 cm3 = 356 L USE 360 L

The worst case tube vo id volume f o r c a l c u l a t i o n o f HL concentrat ions w i t h i n CSB tubes , which i s based on a s i n g l e tube conta in ing two mechanical ly sealed MCOs and t h e i r associated impact l i m i t e r s , i s t h e r e f o r e :

4460 L - 360 L - 280 L - 1210 L - 90 L - 1210 L = 1310 L USE 1300 L

The f o l l o w i n g a d d i t i o n a l volume estimates apply f o r payload conf igura t ions evaluated by t h i s document:

Two welded MCOs and t h e i r associated impact absorbers: 4460 L - 360 L - 280 L - 1260 L - 90 L - 1260 L = 1210 L USE 1200 L

One mechanical ly sealed MCO and both impact absorbers: 4460 L - 360 L - 280 L - 1210 L - 90 L = 2520 L USE 2500 L

F i n a l l y , based on H-2.120918, D r a f t Rev 0 , t h e hold-up volume f o r each o f t h e s h i e l d p l u g ' s two i d e n t i c a l vent p o r t s can be est imated as:

Length - - 30 cm (-11") + 100% allowance f o r n i p p l e , e t c . = 60 cm Diameter - - 1 . 9 cm (0.75 inch) Volume = rr(1.9/2 cm)' x 60 cm = 170 cm3; For two p o r t s

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5.0 COMBUSTIBLE GAS MANAGEMENT FUNCTIONS AND REQUIREMENTS

S i g n i f i c a n t q u a n t i t i e s o f hydrogen can be generated w i t h i n MCOs dur ing t h e f i r s t few years of storage as a r e s u l t o f chemical react ions between exposed uranium metal and any mois ture t h a t i s re ta ined by f u e l p a r t i c u l a t e . Depending on t h e amount o f sludge and re ta ined mois ture w i t h i n a g iven MCO (and a number o f o ther fac to rs ) both hydrogen and oxygen may cont inue t o be generated by r a d i o l y s i s w i t h i n MCOs throughout t h e 40 year CSB operat ing l i f e .

The SNF Pro jec t addresses the p o t e n t i a l f o r combustion o f t h e hydrogen w i t h an o v e r a l l s t ra tegy t h a t , depending on t h e process s tep , employs one o f two general approaches recommended by NFPA 69 t o avoid accumulation o f a combust ib le gas m ix tu re . The funct ions and requirements t h a t implement t h e p r o j e c t ' s o v e r a l l combust ib le gas management s t ra tegy are l i s t e d below.

5 . 1 FUNCTION: PRECLUDE COMBUSTIBLE MIXTURES INSIDE MCOs

it w i l l be necessary t o prov ide t h i s func t i on by l i m i t i n g t h e concentrat ion of oxygen w i t h i n MCOs. addressed by a number o f d i f f e r e n t , but r e l a t e d , s tud ies , analyses, and repo r t s as t h e process design has evolved, cu lminat ing i n Revis ion 3 o f HNF-SD-SNF-TI-040 (MCO In te rna l Gas Composition and Pressure During I n t e r i m Storage). exposed uranium metal surfaces w i t h i n t h e MCO t o remove any oxygen t h a t i s generated by r a d i o l y s i s o f water and establ ished 4 vo l% as t h e L i m i t i n g Oxidant Concentrat ion (LOC) f o r t h e worst case gas mixture w i t h i n an MCO and then used t h a t value ( 4 ~ 0 1 % ) as t h e maximum al lowable oxygen concentrat ion. This a l lowable i s 20% lower (4% versus 5%) than t h a t pe rm i t ted by t h e app l i cab le NRC regu la to ry guide (Control o f Combustible Gas Concentrations i n Containment fo l low ing a Loss-of-Coolant Accident, NRC Regulatory Guide 1 . 7 ) because t h e LOC i t s e l f i s lower f o r t h e MCO's worst case cond i t i ons . Consequently, Table 4 - 1 o f t h e Spent luc lear Fuel Project Product Spec i f i ca t ion (HNF-SD-SNF-OCD-001) spec i f i es a 4 vo l% maximum oxygen concentrat ion instead o f t h e 5 vo l% NRC l i m i t .

Because s i g n i f i c a n t q u a n t i t i e s o f hydrogen are a n t i c i p a t e d w i t h i n MCOs,

Reduction o f oxygen concentrat ions w i t h i n MCOs has been

Revis ion 0 o f t h a t document i n i t i a l l y evaluated t h e a b i l i t y o f

5 .1 .1 Funct ional Requirement : Preclude A i r Ingress t o MCOs

Although, t h e analyses i n HNF-SD-SNF-TI-040 do no t s p e c i f i c a l l y address accumulation o f oxygen w i t h i n MCOs due t o a i r ingress, t h e r e s u l t s i n d i c a t e t h a t t he re i s l i t t l e o r no excess g e t t e r i n g capaci ty t o accommodate ingress of oxygen i n t o t h e MCO. Consequently, one func t i ona l requirement o f t h e MCO handl ing and storage system ( i n c l u d i n g , but not l i m i t e d t o t h e MCO vessel and i t s seals) i s t o e s s e n t i a l l y preclude (as opposed t o l i m i t ) a i r ingress t o an MCO (unless MCOs are p e r i o d i c a l l y purged and b a c k f i l l e d ) .

5.1.1.1 be precluded i t w i l l e i t h e r be necessary t o mainta in an air f r e e (i . e . , oxygen f r e e ) atmosphere around MCOs a t a l l t imes (which w i l l not be p r a c t i c a l , o r even poss ib le ) o r t o mainta in MCOs a t p o s i t i v e gage pressures a t a l l t imes.

While i t i s poss ib le t o design and f a b r i c a t e seals t h a t a re capable o f

Implementation C r i t e r i a . I f air ingress t o MCOs i s t o e s s e n t i a l l y

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prec lud ing any measurable a i r ing ress , t h i s requirement can be more easi l y s a t i s f i e d by s imply ma in ta in ing t h e MCO a t a p o s i t i v e gage pressure. Th is approach has t h e added advantage t h a t i t w i l l au tomat i ca l l y ga in a d d i t i o n a l t ime f o r a l eak ing seal because t h e p o s i t i v e gage pressure must f i r s t be l o s t be fo re any s i g n i f i c a n t amount o f a i r can even begin t o en te r t h e vesse l .

The f o l l o w i n g c r i t e r i a must be s a t i s f i e d i n order t o ma in ta in t h e MCO a t a p o s i t i v e gage pressure, and thereby prec lude a i r i ng ress , under a l l ope ra t i ng c o n d i t i o n s .

5.1.1.1.1 Minimum Time To Maintain P o s i t i v e Pressure. There a r e two cases t h a t must be considered i n order t o e s t a b l i s h t h e minimum t ime du r ing which MCO seals must r e t a i n s u f f i c i e n t b a c k f i l l gas t o ma in ta in p o s i t i v e gage pressure under a l l ope ra t i ng temperature cond i t i ons .

Case 1 - - Transpor t t o t h e CSB and I n i t i a l Stas inq

0 0 Design Goal - - 40 years

Minimum Requirement - - 2 years

The MCOs w i l l employ mechanical seals du r ing t r a n s p o r t t o t h e CSB. most o f t h e MCOs w i l l be prov ided w i t h welded end c losures a s h o r t t i m e a f t e r they a r e received a t t h e CSB, a l i m i t e d number o f MCOs w i l l undergo p e r i o d i c i nspec t i on and gas sampling p r i o r t o i n s t a l l a t i o n o f t h e i r welded caps. it may prove necessary t o mainta in these mechanical ly sealed MCOs w i t h i n t h e CSB f o r severa l yea rs , i t should n o t be d i f f i c u l t t o ensure t h a t each o f them i s se rv i ced on an annual b a s i s , g iven t h e i r small numbers.

necessary t o p rov ide a weld s t a t i o n queue area (i . e . , designated s torage tubes) capable o f s tag ing mechanical ly sealed MCOs w h i l e they awai t i n s t a l l a t i o n o f t h e i r welded c losures. a c t i v e process queue should be on t h e order o f days o r weeks, and because t h e MCOs w i t h i n t h e queue should be easy t o keep t r a c k o f du r ing process delays ( t h e queue's tubes could be prov ided w i t h an i n e r t purge du r ing extended p l a n t shutdowns). a one year minimum b a c k f i l l r e t e n t i o n t ime should be adequate f o r these in-process MCOs.

Based on t h e above considerat ions, and a l l ow ing f o r a 100% cont ingency. t h e minimum t ime f o r a mechanical ly sealed MCO t o ma in ta in p o s i t i v e b a c k f i l l pressure i s 2 yea rs . Whi le , two years i s t h e minimum r e t e n t i o n p e r i o d , CSB operat ions would be s i m p l i f i e d i f t h e r e were no l i m i t (beyond t h e CSB's c u r r e n t 40 year design l i f e ) t o t h e t ime t h a t mechanical ly sealed MCOs can r e t a i n p o s i t i v e b a c k f i l l pressure. Consequently, it i s a h i g h l y d e s i r a b l e (a l though n o t abso lu te l y necessary) goal t o con f i rm t h a t a mechanica l ly sealed MCO w i l l ma in ta in a p o s i t i v e b a c k f i l l pressure f o r a t l e a s t 40 yea rs .

Note t h a t MCO temperatures w i l l vary as a r e s u l t o f decay heat v a r i a t i o n s among t h e MCOs, and as a r e s u l t o f seasonal v a r i a t i o n s i n t h e CSB's c o o l i n g a i r i n l e t temperature. While t h e minimum molar q u a n t i t y o f b a c k f i l l gas must be c a l c u l a t e d a t t h e minimum a n t i c i p a t e d MCO gas temperature, t h e b a c k f i l l gas leakage r a t e must be ca l cu la ted a t t h e gas temperature t h a t corresponds t o t h e maximum a n t i c i p a t e d gas pressure) . A lso note t h a t , even though t h e b a c k f i l l gas leakage c a l c u l a t i o n must i nc lude t h e maximum poss ib le generated gas i nven to ry , no al lowance can be inc luded f o r any o f t h e generated gas when

While

While

I n a d d i t i o n t o t h e mechanical ly sealed MCOs discussed above, i t may be

Because t h e turnaround t ime i n an

9

HNF-2155 Rev 1

e s t a b l i s h i n g t h e minimum end-point pressure because a l l , or most, o f it could be ge t te red by uranium a t any t ime du r ing t h e p r o j e c t l i f e .

Case 2 - - Lonq Term ( " I n t e r i m " ) Storaqe

0 Minimum Requirement - - 40 years

Storage") w i l l n o t begin f o r any g iven MCO u n t i l i t s weld c losu re has been i n s t a l l e d . Fol lowing weld c losu re i n s t a l l a t i o n , MCOs must r e t a i n an adequate q u a n t i t y o f b a c k f i l l gas t o mainta in a p o s i t i v e gage pressure f o r 40 yea rs .

Desiqn Goal f o r Retent ion o f Add i t i ona l B a c k f i l l Gas

Considerable t ime and expense t h a t would otherwise be requ i red t o per form a d d i t i o n a l computer analyses w i l l be avoided i f i t can a l s o be demonstrated t h a t t h e minimum b a c k f i l l pressure i s s u f f i c i e n t t o ensure r e t e n t i o n o f a 30 .3 gmol minimum inven to ry a f t e r 40 years (as opposed t o on l y t h a t requ i red t o ma in ta in a p o s i t i v e gage pressure) . Therefore, an a d d i t i o n a l 40 year goal i s t o ensure t h a t no MCO w i l l ever con ta in l e s s than 30.3 gmol o f He, which i s t h e minimum inven to ry used f o r t h e cu r ren t design bas i s eva lua t i on o f oxygen concentrat ions w i t h i n MCOs (see HNF-SO-SNF-TI-040. Rev 3 ) .

5.1.1.1.2 Type o f B a c k f i l l Gas. The b a c k f i l l gas must be i n e r t . Gasses t h a t might be consumed by r e a c t i n g o r o therwise i n t e r a c t i n g w i t h uranium metal ( e . 9 . . hydrogen o r n i t rogen) are unacceptable because t h e r e i s no way t o be c e r t a i n t h a t t hey w i l l be replaced by generat ion o f a d d i t i o n a l hydrogen. o r t h a t any a d d i t i o n a l hydrogen t h a t i s generated w i l l no t be ge t te red by t h e uranium. b a c k f i l l gas. document a re based on a hel ium b a c k f i l l . I n t h e event some o the r i n e r t gas were t o be se lec ted . t h e hel ium based c a l c u l a t i o n s would be conservat ive i n view o f t h e f a c t t h a t he l ium has t h e h ighest leakage r a t e o f any i n e r t gas

5.1.1.1.3 Maximum B a c k f i l l Pressure. The maximum MCO b a c k f i l l pressure and t h e minimum MCO gas temperature du r ing t h e b a c k f i l l ope ra t i on have been es tab l i shed as 12 .5 p s i g (27.2 ps ia - - 1.85 atm) and O'C, r e s p e c t i v e l y (see sect ions 4 . 3 and 4 . 4 ) . The maximum MCO b a c k f i l l pressure and minimum MCO gas temperature a r e based on l i m i t i n g t h e i n e r t gas a l l o c a t i o n t o a maximum value o f 41.3 gmol f o r an MCO w i t h a 500 L minimum i n t e r n a l vo id volume. While t h e actual b a c k f i l l q u a n t i t y w i l l vary upwards from t h e 41.3 gmol va lue f o r MCOs w i t h f r e e volumes g rea te r than t h e 500 L minimum, t h e l a r g e r b a c k f i l l q u a n t i t y w i l l n o t r e s u l t i n over p r e s s u r i z a t i o n because t h e b a c k f i l l gas q u a n t i t y represents l e s s than h a l f o f t h e worst case gas a l l o c a t i o n used t o c a l c u l a t e t h e maximum pressure. I n o the r words, f o r a g iven b a c k f i l l pressure and temperature, l a r g e r MCO volumes w i l l r e s u l t i n lower worst case pressures (no te t h a t b a c k f i l l pressure and temperature were s p e c i f i e d i ns tead o f gmol i n order t o take advantage o f t h i s automatic compensation e f f e c t ) .

5.1.1.1.4 Minimum B a c k f i l l Pressure. The minimum b a c k f i l l pressure must be h igh enough t o ensure t h a t t h e r e s u l t i n g molar q u a n t i t y o f b a c k f i l l gas w i l l be s u f f i c i e n t t o a l l o w f o r seal leakage and s t i l l ma in ta in a p o s i t i v e pressure w i t h i n MCOs t h a t a r e a t temperatures as low as -31T (see s e c t i o n 4 . 4 ) . Based on t h e 12.5 p s i g maximum b a c k f i l l pressure, and based on t h e f o l l o w i n g l o g i c . i t w i l l be necessary t o demonstrate t h a t a 9 .5 p s i g (24.2 ps ia - - 1.65 atm)

For t h e purposes o f t h i s document, l ong term storage (i . e . , " I n t e r i m

A t t h i s p o i n t i n t h e p r o j e c t , he l ium has been se lected as t h e Consequently, t h e leakage c a l c u l a t i o n s t h a t support t h i s

10

HNF-2155 Rev 1

minimum b a c k f i l l pressure i s s u f f i c i e n t t o meet t h e above requirement

The nominal f i l l pressure must be low enough t o p rov ide a reasonable margin between t h e nominal va lue and t h e s p e c i f i e d maximum value (12 .5 p s i g ) An al lowance o f 1 . 5 p s i i s considered necessary i n order t o accommodate inst rument e r r o r and s t i l l p rov ide a contingency al lowance between t h e actual maximum c o n d i t i o n and t h e s p e c i f i e d maximum f i l l pressure. Consequently, an 11 p s i g (25.7 ps ia - - 1 .75 atm) nominal f i l l pressure was assumed f o r t h e purpose o f e s t a b l i s h i n g t h e minimum f i l l pressure and con f i rm ing t h a t i t i s s u f f i c i e n t t o meet t h e requirements l i s t e d i n t h e preceding. Based on a s i m i l a r s a f e t y margin (i . e . , 1 . 5 p s i ) between t h e nominal va lue and t h e minimum requ i red f i l l pressure, a minimum i n i t i a l b a c k f i l l pressure o f 9 .5 p s i g (24.2 p s i a - - 1 .65 atm) was se lected f o r eva lua t i on . Eva lua t i on o f t h e s e a l ' s a b i l i t y t o r e t a i n he l ium over t ime must, t h e r e f o r e , be based on an i n i t i a l molar q u a n t i t y o f he l ium t h a t corresponds t o an i n i t i a l f i l l pressure o f 1 .65 atm absolute a t some maximum al lowable MCO f i l l temperature. The maximum a l l owab le MCO Transport Cask temperature has been s p e c i f i e d as 25'CC. which corresponds t o a 42'C maximum MCO gas temperature (see sec t i on 4 . 4 ) This works ou t t o 31.9 gmol o f he l ium f o r t h e 500 I minimum MCO v o i d volume (see s e c t i o n 6 . 1 . 2 . 1 ) . For those MCOs ( i , e . , most o f them) t h a t exceed t h e minimum vo id volume, t h e actual b a c k f i l l gas q u a n t i t y w i l l increase p r o p o r t i o n a l l y wi th t h e increase i n v o i d volume, which means t h a t an i n i t i a l b a c k f i l l pressure t h a t i s adequate f o r a minimum v o i d volume MCO w i l l a l s o be adequate f o r a maximum volume MCO.

As noted i n sec t i on 5 . 1 . 1 . 1 . 1 , an a d d i t i o n a l design goal i s t o ensure t h a t t h e MCO w i l l never con ta in l e s s than 30.3 gmol o f He, which i s t h e hel ium inven to ry used i n t h e cu r ren t design bas i s eva lua t i on o f oxygen concentrat ions within MCOs (see HNF-SD-SNF-TI-040, Rev. 3 ) . Therefore, t h e 1 .65 atm minimum b a c k f i l l pressure w i l l be evaluated against t h a t goal as w e l l .

5.1.2

Chapter 2 o f NFPA 69 covers a p p l i c a t i o n o f t h a t s tandard 's ox idan t reduc t i on technique. Paragraph 2 -7 .2 prov ides t h e opera t i ng l i m i t s and ins t rumen ta t i on requi rements f o r systems t h a t w i 11 be operated below t h e I O C Paragraph 2 - 7 . 2 . 2 requ i res t h a t t h e LOC f o r a g iven system be based on t h e worst c r e d i b l e case gas m ix tu re y i e l d i n g t h e smal lest IOC. requ i res t h a t a s a f e t y margin be maintained between t h e LOC and normal working concen t ra t i on i n t h e system. summary d e s c r i p t i o n o f NFPA 69.

5.1.2.1 Non-Compl i ance w i t h S p e c i f i c Requirements. Paragraph 2 -7 .2 .5 o f NFPA 69 s t a t e s : "Where t h e ox idant concentrat ion i s c o n t i n u a l l y monitored, a s a f e t y margin o f a t l e a s t 2 volume percent below t h e measured worst c r e d i b l e case IOC s h a l l be maintained unless t h e LOC i s l e s s than 5 pe rcen t , i n which case t h e equipment s h a l l be operated a t no more than 60 percent o f t h e IOC. Paragraph 2 -7 .2 .5 can no t be app l i ed t o an MCO a f t e r it leaves t h e CVDF because i t w i l l have no p r o v i s i o n f o r continuous mon i to r i ng .

Paragraph 2-7.2.6 s t a t e s , i n p a r t : "Where t h e oxygen concen t ra t i on i s n o t cont inuously monitored. t h e oxygen concentrat ion s h a l l be designed t o operate a t no more than 60 percent o f t h e LOC, o r 40 percent o f t h e LOC i f t h e I O C i s be l ow 5 percent . "

NFPA 69 Paragraph 2-7 .2 Compliance Status

Paragraph 2 - 7 . 2 . 3

See Appendix B o f t h i s document f o r an o v e r a l l

11

HNF-2155 Rev 1

0 Based on t h e 4 vo l% LOC discussed i n sec t i on 2 . 1 above, compliance with t h e l e t t e r o f t h e above statement would r e q u i r e t h a t t h e o v e r a l l SNF Pro jec t f u e l removal and s torage process ( e . g . , t h e f u e l c lean ing process, maximum MCO f u e l and/or scrap i nven to ry , f u e l d r y i n g process. MCO b a c k f i l l gas t ype and/or q u a n t i t y , e t c . ) be designed t o ensure t h a t t h e oxygen concentrat ion w i t h i n MCOs w i l l n o t exceed 1 . 6 v o l % a t any t ime du r ing t h e i r se rv i ce l i f e

I n view o f t h e f a c t t h a t t h e cu r ren t oxygen g e t t e r i n g goal i s t o mainta in t h e oxygen concen t ra t i on w i t h i n a l l MCOs a t o r below t h e LOC (as opposed t o 40% o f t h e LOC), t h e SNF P r o j e c t does n o t appear t o comply w i t h t h e above NFPA 69 requirement

impor tant t o recognize t h a t NRC Regulatory Guide 1.7 i s a l s o apparent ly ou t o f compliance.

Even g iven a 5 v o l % LOC, t h e NRC g u i d e ' s maximum a l l owab le oxygen concentrat ion would have t o be s p e c i f i e d as 60% o f t h e 5 vo l% LOC, o r 3 v o l % oxygen, as opposed t o 5 ~ 0 1 % .

Paragraph 2 - 7 . 2 . 6 f u r t h e r s t a t e s : "If t h e oxygen concen t ra t i on i s no t

- With respect t o t h e above, apparent, non-compliance, i t i s

cont inuously monitored, t h e oxygen concentrat ion s h a l l be checked on a r e g u l a r l y scheduled bas i s . "

0 The SNF P r o j e c t w i l l be unable t o comply w i t h t h i s requirement once a g iven MCO's weld c losu re has been i n s t a l l e d .

5.1.2.2 NFPA 69 Paragraph 2-7.2 Equivalency. Although i t i s impossib le t o c l a i m s t r i c t compliance w i t h NFPA 69 Paragraph 2 -7 .2 i n l i g h t o f t h e s i t u a t i o n descr ibed i n sec t i on 5 . 1 . 2 . 1 above, it i s poss ib le t o demonstrate t h a t bo th t h e SNF P r o j e c t and t h e NRC Regulatory Guide 1 .7 do p rov ide an equ iva len t l e v e l o f p r o t e c t i o n . Paragraph 1 - 1 . 3 o f NFPA 69 prov ides f o r demonstrat ion of equivalency (see Appendix B o f t h i s document).

and mon i to r i ng requirements invoked by Paragraph 2 -7 .2 , desp i te t h e p r o j e c t ' s i n a b i l i t y t o s t r i c t l y comply w i t h those l i m i t s and requirements, i t i s necessary t o compare t h e operat ional bases t h a t drove t h e NFPA 69 requirements t o those t h a t drove t h e MCO's 4 vo l% oxygen l i m i t and t h e s i m i l a r 5 v o l % l i m i t es tab l i shed by t h e NRC Regulatory Guide.

I n t h e i ns tance o f t h e 5 v o l % oxygen l i m i t invoked by NRC Regulatory Guide 1 . 7 (Con t ro l o f Combustible Gas Concentrat ions i n Containment Fo l l ow ing a Loss-of-Coolant Acc iden t ) , t h e d i f f e r e n c e i s apparent from t h e phrase " l o s s o f coo lan t acc iden t " i n t h e gu ide ' s t i t l e . and mon i to r i ng requirements o f NFPA 69 are based on normal ope ra t i on a t concen t ra t i on l e v e l s t h a t approach t h e s p e c i f i e d maximum (3 v o l % oxygen f o r t h e NRC's 5 v o l % oxygen LOC), t h e NRC's 5 ~ 0 1 % l i m i t has no th ing t o do w i t h normal ope ra t i on b u t i s , i ns tead , d i r e c t e d toward a design bas i s acc iden t .

The MCO's s i t u a t i o n i s s i m i l a r , bu t n o t i d e n t i c a l , t o t h a t addressed by t h e NRC. reac to r containment because the re i s normal ly no hydrogen t o r e a c t wi th t h a t oxygen, which i s why t h e scope o f NRC Regulatory Guide 1 . 7 i s l i m i t e d t o l o s s

12

I n order t o demonstrate equivalency t o t h e oxygen concen t ra t i on l i m i t s

Whereas t h e concen t ra t i on l i m i t s

There i s no bas is f o r a "normal operat ing l i m i t " f o r oxygen w i t h i n a

HNF-2155 Rev 1

o f coo lan t acc iden t . b u i l d i n g du r ing normal operat ion i n order t o ensure t h a t oxygen l e v e l s can n o t exceed 5 v o l % du r ing o r a f t e r a pos tu la ted acc ident , t h e i n e r t i n g requirement i s d i r e c t e d pu re l y a t t h e acc ident cond i t i on , as opposed t o normal ope ra t i on .

The MCO. on t h e o the r hand, must be assumed t o con ta in s i g n i f i c a n t q u a n t i t i e s o f hydrogen du r ing normal ope ra t i on , t h e r e f o r e any l i m i t a t i o n on t h e oxygen concen t ra t i on must, by d e f i n i t i o n , be d i r e c t e d a t normal ope ra t i on . Whereas t h e d i f f e r e n c e between t h e NRC bas i s and t h e NFPA 69 bas is i s t h a t o f an acc ident c o n d i t i o n versus a normal ope ra t i ng cond i t i on , t h e d i f f e r e n c e between t h e MCO's bas is and NFPA 69's bas is concerns t h e methodology t h a t i s used t o prec lude combustion.

ma in ta in ing a purge gas b lanke t and/or f l o w t h a t normal ly w i l l n o t exceed t h e p a r t i c u l a r l i m i t imposed. The l o g i c i s t h a t , i n t h e event t h a t something goes wrong wi th t h e purge gas system ( e . g . , a l e a k i n g f l ange on t h e i n t a k e s i d e o f an " i n e r t gas" compressor's f i r s t stage. e t c . ) , t h e a d d i t i o n a l margin a f fo rded by NFPA 69's requirements w i l l genera l l y be s u f f i c i e n t t o prevent t h e LOC from being g r e a t l y exceeded f o r any s i g n i f i c a n t pe r iod o f t ime . demonstrate by a r i go rous a n a l y t i c a l model t h a t i t w i l l n o t be reached.

s a t i s f i e s NFPA 69. Paragraph 1 - 1 . 3 . which addresses s i t u a t i o n s where i t i s e i t h e r impossib le o r i napprop r ia te t o meet any o r a l l o f t h e d e t a i l e d requirements t h a t i t invokes. That paragraph s t a t e s : "Nothing i n t h i s standard s h a l l be in tended t o prevent t h e use o f systems, methods, o r devices o f equ iva len t o r super io r q u a l i t y , s t reng th , f i r e res i s tance , e f f e c t i v e n e s s , d u r a b i l i t y , and s a f e t y over those prescr ibed by t h i s standard, prov ided techn ica l documentation i s made a v a i l a b l e t o t h e a u t h o r i t y hav ing j u r i s d i c t i o n t o demonstrate equivalency and t h e system, method, o r dev ice i s approved fo r t h e in tended purpose.

5.1.2.2.1 S t ra tegy To Achieve NFPA 69 Paragraph 2-7.2 Equivalency. Formal recommendation o f t h e SNF P ro jec t s t ra tegy t o document and o b t a i n o f f i c i a l r e c o g n i t i o n o f NFPA 69 Paragraph 2-7.2 equivalency i s beyond t h e scope o f t h i s document. Depending on t h e f i n d i n g s o f ongoing analyses, i t may, o r may n o t , be poss ib le t o document equivalency by demonstrat ing t h a t t h e vast m a j o r i t y o f MCOs w i l l n o t con ta in oxygen a t concentrat ions above 1.6 ~ 0 1 % . and t h a t t h e 4 v o l % LOC would on l y be approached ( o r poss ib l y reached) by a bounding case MCO. F a i l i n g t h a t , i t may be poss ib le t o demonstrate t h a t an MCO can s a f e l y con ta in a d e f l a g r a t i o n (as opposed t o a detonat ion) f o r a worst case s e t o f cond i t i ons i n accordance w i t h Chapter 5 o f NFPA 69. Because, Paragraph 1-1.2 of NFPA 69 excludes detonat ions from i t s scope, eva lua t i on o f t h e corresponding detonat ion would then be performed t o DOE and NRC requirements.

While it may be necessary t o i n e r t t h e containment

For most a p p l i c a t i o n s governed by NFPA 69, i t i s s imply a mat ter o f

No one has t o

I n view o f t h e above, i t may be poss ib le t o p rov ide documentation t h a t

5.2 FUNCTION: PRECLUDE COMBUSTIBLE MIXTURES OUTSIDE MCOs

shipp ing casks and s torage tubes, i t w i l l be necessary t o p rov ide t h i s f u n c t i o n by l i m i t i n g t h e concentrat ion o f hydrogen w i t h i n t h e casks and tubes.

I n order t o pe rm i t MCOs t o be handled and s to red w i t h i n a i r f i l l e d

13

HNF-2155 Rev 1

5 .2 .1

I n order t o l i m i t t h e concentrat ion o f hydrogen w i t h i n t h e a i r f i l l e d casks and tubes t h a t handle and s t o r e MCOs, it w i l l e i t h e r be necessary t o cont inuously o r p e r i o d i c a l l y exchange t h e cask o r tube a i r , o r i t w i l l be necessary t o l i m i t t h e re lease o f hydrogen from MCOs. Because i t would be very d i f f i c u l t t o ensure abso lu te l y r e l i a b l e a i r exchange, t h e p r o j e c t w i l l p rov ide t h a t f u n c t i o n by l i m i t i n g t h e re lease o f hydrogen from MCOs.

5 .2 .1 .1 Implementation C r i t e r i a .

5.2.1.1.1 Acceptable H, Concentrat ion, 51 .0 vo l% H,

5.2.1.1.2 Minimum Time To Maintain Acceptable H, Concentrat ion

CASE 1 - - Mechanical ly Sealed MCOs (S inq l y OccuDied CSB Tube): 1 year

be sampled and v e n t i l a t e d every 8 months o r so. t h e minimum c r i t e r i o n f o r a s i n g l y occupied tube con ta in ing a mechanica l ly sealed MCO. i t i s recognized t h a t maximum opera t i ng f l e x i b i l i t y and minimum cos t would be r e a l i z e d i f t h e mechanical seals ( i n con junc t i on w i t h d i l u t i o n v i a t h e s torage tube vent p o r t s ) can be shown t o l i m i t steady s t a t e hydrogen concentrat ions t o 1 v o l % o r l e s s w i t h i n un-sealed tubes con ta in ing two mechanica l ly sealed MCOs.

CASE 2 - - Welded MCOs (Doubly Occupied CSB Tube): 40 years

Funct ional Requirement: L i m i t H, Release From MCOs

Th is would r e q u i r e t h a t a g iven tube con ta in ing a mechanical ly sealed MCO Note t h a t , w h i l e one year i s

5.2.2

Chapter 3 o f NFPA 69 covers a p p l i c a t i o n o f t h e combustible reduc t i on technique. Paragraph 3-3 prov ides design and opera t i ng requirements f o r systems t h a t w i l l be operated below t h e Lower Flammable L i m i t (LFL) . See Appendix B o f t h i s document f o r an o v e r a l l summary d e s c r i p t i o n o f NFPA 69.

Paragraph 3 - 3 . 1 o f NFPA 69 requ i res t h a t t h e combustible concen t ra t i on be maintained a t o r below 25% o f t h e LFL ( i . e . . 25% o f 4 v o l % f o r hydrogen i n a i r works o u t t o 1 ~ 0 1 % ) . concentrat ions up t o 60% o f t h e LFL f o r systems t h a t have t h e c a p a b i l i t y t o au tomat i ca l l y shut o f f t h e source o f combustible ma te r ia l or otherwise prevent a combustion event (automat ic a c t i v a t i o n o f quenching systems, e t c . ) by means o f i ns t rumen ta t i on w i t h s a f e t y i n t e r l o c k s .

I n view o f t h e cu r ren t hydrogen management goal t o ma in ta in t h e hydrogen concen t ra t i on w i t h i n any CSB s torage tube ( i n c l u d i n g those t h a t con ta in s a f e t y bas i s pressure MCOs) a t o r below 25% o f t h e LFL ( i . e . , a t or below 1 v o l % hydrogen). and i n view o f t h e r e s u l t s i n t h i s document, which con f i rm t h e a b i l i t y o f t h e MCO seals t o meet t h e 1 v o l l maximum concen t ra t i on g o a l , i t should be easy t o demonstrate t h a t t h e SNF Pro jec t i s i n compliance w i t h t h e above NFPA 69 requirement, prov ided t h a t a l l t h e necessary documents a re i n p lace ( e . g . , gas i nven to ry c a l c u l a t i o n s , hydrogen leak r a t e and b u i l d - i n c a l c u l a t i o n s [prov ided by t h i s document], leak t e s t r e p o r t s , e t c . 1 .

NFPA 69 Paragraph 3 - 3 Compliance Status

An except ion i s prov ided t o a l l ow combust ib le

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6.0 PREDICTION OF OPERATIONAL LEAKAGE FROM LEAK TEST RESULTS

The c u r r e n t Performance S o e c i f i c a t i o n f o r t h e Soent Nuclear Fue l M u l t i - Can is te r Overpack (HNF-S-0426j s p e c i f i e s t h e fo l lowi 'ng l eak t e s t acceptance c r i t e r i a f o r t h e MCO:

0 1 x scc isec maximum i n t e g r a t e d l eak r a t e p r i o r t o i n s t a l l a t i o n o f f i n a l c losu re weld.

1 x lO~' scc/sec maximum i n t e g r a t e d l eak r a t e f o l l o w i n g i n s t a l l a t i o n o f f i n a l c losu re weld.

0

I n order t o e i t h e r con f i rm t h a t t h e above leak t e s t acceptance c r i t e r i a a re adequate o r e s t a b l i s h rev i sed c r i t e r i a , t h e c a l c u l a t i o n s must: 1) assume t h a t some o f t h e MCOs w i l l i nc lude leak paths t h a t would produce t e s t i n g r e s u l t s corresponding t o those c r i t e r i a (i . e . , t h a t some MCOs almost f a i l t h e leak t e s t ~- considered u n l i k e l y ) ; 2) p r e d i c t leakage ra tes t h a t would r e s u l t from those leak paths under t h e actual ope ra t i ng cond i t i ons ( e . g . , gas composi t ion, pressure, temperature, e t c . ) : and 3) evaluate t h e p red ic ted leakage r a t e s against t h e MCO's gas management func t i ons and requi rements.

6.1 LEAKAGE CORRELATION DEFIN IT IONS AND METHODOLOGY

M a t e r i a l s - - leakage t e s t s on packages f o r shipment (ANSI N14.5-1987) de f i nes t h e term " s t d cm3/s" as a leakage r a t e " r e f e r r i n g t o t h e standard cond i t i ons f o r d ry a i r a t 1 atmosphere ( a t m ) absolute pressure (101 kPa) and 298 K (25°C) . " That sec t i on a l so def ines " l e a k t i g h t " as "a leakage r a t e l e s s than o r equal t o 1 X 1U7 s t d cm3/s, a t an upstream pressure o f 1 atm abs and a downstream pressure o f 0 .01 atm abs o r l e s s , i r r e s p e c t i v e o f t h e r a d i o a c t i v e con ten ts .

Sec t i on 4.13 o f t h e cu r ren t MCO performance s p e c i f i c a t i o n (HNF-S-0426) requ i res a l l MCO seals t o be " . . . leakage r a t e t e s t a b l e i n accordance w i t h ANSI N14.5". Therefore i t fo l l ows from t h e above d e f i n i t i o n s t h a t t h e MCO's s p e c i f i e d 1 x r e f e r t o t h e volume o f d ry a i r ( a s opposed t o he l ium o r hydrogen), co r rec ted t o an absolute pressure o f one atmosphere and 25OC, t h a t w i l l f l o w through a l eak pa th from an upstream c a v i t y w i t h a n absolute pressure o f one atmosphere i n t o a downstream c a v i t y t h a t has been evacuated t o 0 .01 atm abs, o r l e s s

While t h e ANSI standard prov ides a wide range o f op t i ons w i t h respect t o bas i c t e s t i n g methods (pressure decay, gas de tec t i on , e t c . ) , phys i ca l t e s t i n g arrangements ( inward f l o w , outward f l ow , e t c . ) , and t e s t cond i t i ons ( t e s t medium, temperature, pressure, e t c . ) , t h e t e s t r e s u l t s a re always repo r ted as an a i r leakage r a t e t h a t would have occurred a t t h e exact combination o f upstream pressure, downstream pressure, and temperature t h a t i s s p e l l e d ou t i n t h e above paragraph.

Sect ion 3 ( D e f i n i t i o n s ) o f t h e American Na t iona l Standard Fo r Radioact ive

scc isec and 1 x l V 7 scc isec leakage acceptance c r i t e r i a

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6.1.1

A l l o f t h e c a l c u l a t i o n s i n t h i s document t h a t p r e d i c t ope ra t i ona l leakage (i . e . , leakage " a t pressure") from standard l eak t e s t acce tance c r i t e r i a a r e based on t h e f l o w c o r r e l a t i o n equations t h a t a r e prov ided Ey,Appendix B , o f ANSI N14.5-1997, D r a f t J . as opposed t o t h e equations and guidance prov ided by t h e re leased ve rs ion (ANSI N14.5-1987). d r a f t ve rs ion i ns tead o f t h e re leased ve rs ion i s prov ided below.

cond i t i ons t o leakage under actual operat ing cond i t i ons . To accomplish t h i s . it prov ldes a s e t o f equations t o e s t a b l i s h t h e diameter o f a f i c t i t i o u s s i n g l e ho le " t h a t would r e s u l t i n t h e observed t e s t f l o w r a t e . The f i c t i t i o u s h o l e i s assigned an a r b i t r a r y l eng th , t y p i c a l l y 1 cm ( p r e l i m i n a r y c a l c u l a t i o n s f o r t h i s document used values from 1 cm down t o 0.025 cm). The standard then p r e d i c t s t h e f l ow r a t e a t t h e opera t i ng cond i t i ons by app ly ing t h e c a l c u l a t e d h o l e diameter and assumed leng th t o t h e same equations ( o r o t h e r s , depending on t h e f l o w regime) a f t e r a d j u s t i n g var ious parameters (temperature, pressure, gas composit ion, e t c . ) t o represent t h e ac tua l ope ra t i ng c o n d i t i o n s .

S p e c i f i c a l l y , Appendix B o f t h e 1987 re lease prov ides €9 82, t o t a l f l o w : €9 83, continuum f l o w , and €9 84, molecular f l ow , a l l o f which a r e l i m i t e d t o c a l c u l a t i o n o f unchoked f l ow . It prov ides €9 87 f o r choked f l o w . F i n a l l y , i t prov ides €9 85 t o determine whether o r no t choked f l o w i s poss ib le , based on t h e r a t i o o f continuum f l o w t o molecular f l o w ( t h e c r i t i c a l pressure r a t i o must a l s o be s a t i s f i e d ) . cond i t i ons t h a t f avo r molecular f l o w , t h e apparent h o l e diameter i s t y p i c a l l y c a l c u l a t e d v i a €95- 82 through 83. The 1987 ve rs ion o f t h e standard then uses an o r i f i c e t y p e equat ion (€9 87) t o p r e d i c t t h e f l o w r a t e under h igh pressure p l a n t cond i t i ons a t which t h e f l o w i s most ly continuum and t h e r e f o r e choked (per €9 85 - - t h e c r i t i c a l pressure r a t i o i s s a t i s f i e d i n both cases) .

The shortcomings o f t h e above approach a re i nhe ren t (a l though they were n o t immediately apparent) i n Tab7e 82 ( A i r Leakage f o r Various Ho7e Diameters) o f t h e 1987 re lease , which prov ides c a l c u l a t e d f l o w r a t e s based on t h e equations and gu ide l i nes prov ided by t h e standard. The c a l c u l a t e d values i n t h e f i r s t column o f t h e t a b l e i n d i c a t e a d i s c o n t i n u i t y i n t h e f l o w reg ion between lw3 s t d cc/sec and 10.' s t d cc/sec. This would imply a " t r a n s i t i o n a l " f l o w regime spanning many decades. That t a b l e has been complete ly rev i sed i n t h e 1997 d r a f t o f t h e standard.

Problems were f i r s t encountered du r ing t h e i n i t i a l attempt t o determine whether t h e standard l eak cond i t i ons would r e s u l t i n choked f l o w o r unchoked f l o w a t t h e mechanical s e a l ' s [ then] s p e c i f i e d 1 x lU4 scc/s l eak r a t e . When t h e equations f o r unchoked f l o w were used, €9 85 determined t h a t t h e f l o w was choked, whereas t h a t same equat ion determined t h e f l o w t o be unchoked when app l i ed t o r e s u l t s from t h e choked f l o w equation. Th is c o n d i t i o n i s t y p i c a l l y r e f e r r e d t o as " t r a n s i t i o n a l f l o w , " although i n many cases i t i s r e a l l y an a r t i f a c t of t h e p r e d i c t i v e methodology and has no th ing t o do w i t h ac tua l f l o w .

While t h e above " t r a n s i t i o n a l f l ow" problems were no t encountered w i t h i n i t i a l c a l c u l a t i o n s f o r t h e 1 X l O - ' s t d cc/sec leak t e s t acceptance c r i t e r i o n . t h e under l y ing problems i n t h e o v e r a l l approach even tua l l y became apparent. The f low regime was p l a i n l y unchoked a t t h e t e s t cond i t i ons and

Shortcomings O f The ANSI N14.5-1987 Approach

J u s t i f i c a t i o n f o r us ing t h e c u r r e n t

ANSI N14.5 prov ides guidance f o r c o r r e l a t i o n o f leakage under t e s t

Because most leak t e s t i n g i s performed under

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p l a i n l y choked a t t h e operat ing cond i t i ons , which was encouraging. t h e subsequent c a l c u l a t i o n p red ic ted t h a t a p ipe weld would e x h i b i t gross leakage a t t h e opera t i ng cond i t i ons . desp i te t h e f a c t t h a t t h e weld had s a t i s f i e d a 1 X lO . ' s td cc/sec leak t e s t acceptance c r i t e r i o n . f o r t h i s s i t u a t i o n i s t h a t t h e choked f l o w equat ion (Eq 57) does no t cons ider t h e h o l e ' s l eng th a t a l l , whereas t h e h o l e ' s diameter was obta ined us ing equations (Eq 82. e t . a l . ) wherein t h e ca l cu la ted f l o w r a t e f o r a g i ven h o l e diameter i s an i nve rse l i n e a r f u n c t i o n o f t h e h o l e ' s l eng th .

However,

The reason

6.1.2

I n order t o e l i m i n a t e t h e problems inherent i n t h e 1987 re lease, Sect ion 64 (CorreJat ion Between Gas Leakage Rates a t D i f f e r e n t Condi t ions) of ANSI N14.5-1997 J e l im ina tes a l l guidance f o r c o r r e l a t i o n o f molecular f l o w cond i t i ons t o choked f l o w cond i t i ons and e l im ina tes t h e choked f l o w equat ion (Eq 57) . Sect ion B3 (Gas Leakage) prov ides a new f l o w equat ion (5-51, however t h i s equat ion i s n o t a replacement f o r Eq 87 and has no th ing t o do w i t h choked f l o w . no r w i t h t h e o r i g i n a l fq 55 (see sec t i on 6 . 1 . 1 above), which has a l s o been e l im ina ted . The new equat ion 5-5 i s j u s t an extens ion o f t h e o r i g i n a l fq 52. which (now labe led 6-21 remains t h e bas ic f l ow equat ion. was in t roduced i n order t o fo rma l i ze t h e pressure bas i s r e l a t i o n s h i p s among t h e var ious vo lumetr ic f l ow ra tes t h a t can be ca l cu la ted f o r t h e same molar f low r a t e , depending on whether t h e f l o w r a t e i s ca l cu la ted a t t h e upstream pressure, t h e downstream pressure, o r t h e average pressure.

The n e t r e s u l t o f these changes i s t h a t t h e f i r s t column o f t h e rev i sed Table 52 (now labe led TabJe 5.2) prov ides f i v e d i f f e r e n t ca l cu la ted leakage r a t e s between 1 . 2 x ( re leased) ve rs ion prov ided none i n t h a t range. l i s t e d a ca l cu la ted leakage r a t e o f 1 . 4 x 10. scc/sec f o r a 3 x cm h o l e d iameter , t h e new ve rs ion l i s t s a ca l cu la ted leakage r a t e below 1W6 scc/sec fo r t h e same h o l e (no te t h a t t h e h o l e ' s l eng th i s l i s t e d as 1 cm i n bo th cases). magnitude) between t h e re leased vers ion o f t h e t a b l e and t h e new d r a f t ve rs ion i s t h a t t h e re leased ve rs ion ca l cu la ted these .leakage ra tes (i . e . , those l i s t e d i n t h e f i r s t column) by using Eq 52 f o r some ho les , and €q 87 (which d isregards t h e h o l e ' s l eng th ) f o r o the rs , whereas t h e d r a f t r e v i s i o n ca l cu la tes a l l leakage ra tes us ing equation 5-5 (equiva lent t o €q 82).

The Revised Approach In ANSI N14.5-1997 Draft J

Equation B-5

scc/sec and 2 x 10.' scc/sec whereas t h e o l d And, whereas t h e o l d ve rs ion

Again, t h e reason f o r t h e gross discrepancy (over t h r e e orders o f

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7.0 CALCULATIONS

7.1 MCO OPERATING CONDITIONS

7.1.1 MCO Gas Temperatures

The maximum and minimum operat ing MCO gas temperatures t o be used f o r c a l c u l a t i o n o f MCO gas pressures o r gas leakage r a t e s w i t h i n t h e CSB have been es tab l i shed as 64'C and -31°C respec t i ve l y . See sec t i on 4 . 4 .

7.1.2 MCO Gas Inventor ies

use o f t h e f o l l o w i n g gas i nven to r ies f o r MCO leakage c a l c u l a t i o n s .

7.1.2.1 The f o l l o w i n g gas i nven to ry assignments a re appropr ia te f o r eva lua t i on o f t h e MCO's l eak t e s t acceptance c r i t e r i a against i t s b a c k f i l l gas (He) r e t e n t i o n requirements (see s e c t i o n 7 . 1 . 2 . 1 , 1 , below, f o r t h e c a l c u l a t i o n t h a t develops t h e minimum i n i t i a l he l ium b a c k f i l l i n v e n t o r y ) .

See s e c t i o n 4 . 3 f o r references and a d d i t i o n a l d iscuss ions t h a t j u s t i f y

Worst Case Gas Inventory For C a l c u l a t i n g Helium Loss.

0 Hydrogen (maximum s a f e t y bas is i nven to ry ) - - - - - - - 65.5 gmol

0 B a c k f i l l gas (minimum f i l l q u a n t i t y o f He) - - - - - - 31 .9 gmol

0 Alpha decay hel ium ( taken as hydrogen) - - - - - - - - - - - - - 0 gmol

0 Noble gasses ( K r . Xe - - taken as hydrogen) - - - - - - - - - 0 gmol

0 Oxygen ( taken as hydrogen) . . . . . . . . . . . . . . . . . . . . . . . . . 0 gmol

97.4 gmol 0 TOTAL __ .__ .__ .__ ._______. .___._____.__ ._____._

7.1.2.1.1 Minimum I n i t i a l B a c k f i l l Gas Q u a n t i t y . The minimum i n i t i a l b a c k f i l l q u a n t i t y i s ca l cu la ted below. This minimum q u a n t i t y i s based on a minimum b a c k f i l l pressure a t a maximum MCO Transport Cask temperature, where t h e cask temperature i s used t o determine t h e gas temperature w i t h i n t h e MCO. Although t h e c a l c u l a t e d minimum molar q u a n t i t y [ f o r a 500 L minimum v o i d space M C O l w i l l n o t appear as an operat ions requirement, i t w i l l p robably have t h e same a d m i n i s t r a t i v e f o r c e because t h e minimum pressure and maximum cask temperature a re expected t o become operat ions requirements. and 5 . 1 . 1 . 1 . 4 f o r t h e maximum temperature and minimum pressure bases.

Maximum MCO gas temperature du r ing b a c k f i l l - - T = 315 K (42°C)

Minimum MCO v o i d volume - - V = 500 L

Minimum b a c k f i l l pressure - - P = (24.2 p s i a ) / ( 1 4 . 7 ps ia /atm) = 1 .65 atm

R = 0.82 L atm/gmol K

PV = nRT: n,mr,a, = PV/RT = minimum i n i t i a l b a c k f i l l gas i nven to ry , gmol:

nlmtla, = (1.65 atm)(500 L ) / [ (0 .082 L atm/gmol K)(315 K ) ] = 31.94 gmol

See sec t i ons 4 . 4

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7.1.2.1.2 Minimum Required MCO Helium Inven to ry . Sect ion 5 . 1 . 1 . 1 requ i res t h a t t h e MCO be maintained a t a p o s i t i v e gage pressure a t a l l t imes , and sec t i on 5.1.1.1.2 s t i p u l a t e s t h a t t h e p o s i t i v e gage pressure be based s o l e l y on an i n e r t b a c k f i l l gas because t h e hydrogen could be ge t te red by uranium meta l . Therefore, t h e leak t e s t acceptance c r i t e r i a must be evaluated t o ensure t h a t t h e minimum b a c k f i l l case MCO (31.9 gmol o f He) w i l l s t i l l r e t a i n a s u f f i c i e n t amount o f he l ium t o ma in ta in a p o s i t i v e gage pressure a t t h e worst case minimum opera t i ng temperature a f t e r t h e s p e c i f i e d s torage t i m e ( s ) a t t h e h ighes t a n t i c i p a t e d p ressu re (s ) . c a l c u l a t e d d i r e c t l y from t h e worst case minimum MCO opera t i ng temperature and t h e MCO’s minimum v o i d volume. Note t h a t t h e minimum vo id volume can be used here (desp i te t h e f a c t t h a t t h e maximum v o i d volume would normal ly c o n t r o l ) because t h e minimum i n i t i a l b a c k f i l l q u a n t i t y (31.9 gmol) i s i t s e l f based on a minimum f i l l pressure w i t h i n a minimum vo id volume MCO. Where t h e ac tua l vo id volume exceeds t h e 500 L minimum vo id volume (which w i l l almost always be t h e case) , t h e i n i t i a l b a c k f i l l q u a n t i t y w i l l a l s o exceed t h e minimum i n i t i a l b a c k f i l l q u a n t i t y by a p ropor t i ona l amount. O f course, t h e minimum requ i red hel ium inven to ry w i l l a l s o be h igher f o r t h a t MCO. b u t so w i l l t h e amount o f expendable hel ium. The minimum requ i red hel ium inven to ry i s based on t h e f o l l o w i n g (See sec t i on 4.0 f o r bases):

The minimum requ i red i nven to ry can be

Minimum MCO temperature du r ing CSB s torage ~- T = 242 K (-31°C)

MCO v o i d volume (see above d iscuss ion) - - V = 500 L

Minimum Acceptable Helium Pressure - - P = 1 .0 atm

R = 0.82 L atm/gmol K

PV = nRT: nflnal = PV/RT = minimum requ i red b a c k f i l l gas i nven to ry , gmol:

nr,nal = ( 1 . 0 atm)(500 L ) / [ ( 0 . 0 8 2 L atm/gmol K)(242 K ) ] = 25.2 gmol

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7.1.2.1.3 Maximum Acceptable Helium Loss. vo id volume (see sec t i on 4.3). and given t h e minimum i n i t i a l he l ium b a c k f i l l i nven to ry and m i nimum requi red he1 i um inventory developed i n sect ions 7.i.2.1.1 and 7.1.2.1.2, t h e maximum acceptable hel ium loss i s :

Given an MCO w i t h a 500 L minimum

nloss = nlnltla, - nflnal = 31.9 gmol - 25.2 gmol = 6.7 m o l , where:

nlosi = maximum acceptable t o t a l hel ium leakage over t ime :

n,,,,t,a, = minimum i n i t i a l b a c k f i l l quan t i t y (per sec 7.1.2.1.1): and

nflnal = minimum requi red hel ium inventory (per sec 7.1.2.1.2)

7.1.2.1.4 Design Goal f o r Maximum Helium Loss. MCO seals w i l l a l s o be evaluated against t h e 30.3 gmol hel ium r e t e n t i o n design goal d iscussed i n t h e l a s t paragraph o f sec t i on 5.1.1.1.1. 7.1.2.1.3. above, t h e maximum des i rab le hel ium loss i s :

nloss = nlnlt,al ~ nflnal = 31.9 gmol - 30.3 gmol = 1 .6 gmol , where:

Per t h e l o g i c presented i n sec t i on

nloss = design goal f o r maximum t o t a l hel ium leakage over t ime :

n,,,,,,,, = minimum i n i t i a l b a c k f i l l quan t i t y (per sec 7.1.2.1.1): and

nfina, = minimum hel ium inventory goal (30.3 gmol).

Unless t h e welding procedure inc ludes an operat ion t o " t o p - o f f ' ' t h e MCO's hel ium b a c k f i l l p r i o r t o welding (which it w i l l no t f o r most MCOs), t h e hel ium l o s s c r i t e r i a must assume an appropr ia te combination o f s tag ing t ime ( p r i o r t o i n s t a l l i n g the weld cap) and s torage t ime ( f o l l o w i n g weld cap i n s t a l l a t i o n ) . The f o l l o w i n g combination o f t imes i s considered conservat ive f o r c a l c u l a t i n g t h e worst-case amount o f hel ium t h a t could be l o s t from any MCO w i t h acceptable leak t e s t r e s u l t s . A l l o c a t i o n o f t h e a l lowable l o s s i s based on i n i t i a l leakage c a l c u l a t i o n s , which i n d i c a t e t h a t e s s e n t i a l l y no hel ium w i l l be l o s t from a welded MCO dur ing f o r t y years o f s torage.

0 Staging Time Requirement (i . e . , p r i o r t o welding) - - 4 years

- Po r t i on o f 1 . 6 gmol maximum loss a l l oca ted t o Staging - - 1.3 gmol

0 I n t e r i m Storage Time ( a f t e r welding) - - 40 years

- Loss a l l o c a t i o n a v a i l a b l e f o r I n t e r i m Storage - - 0 .3 gmol

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7.1.2.2 Worst Case Gas Inventory For C a l c u l a t i n g Hydrogen Release. The following gas inventory assignments represent a worst case condition for evaluation of the MCO's leak tes t acceptance cr i ter ia against the project 's functional requirements t o limit the hydrogen concentration t o 1 vol% w i t h i n the space t h a t surrounds a bounding pressure case MCO. Application of this inventory t o mechanically sealed MCOs during the f i r s t two or three years of their operation i s very conservative because the inventory represents a l l of the hydrogen t h a t could possibly be generated w i t h i n the MCO during 40 years, whereas only about one tenth of t h a t inventory i s expected t o be generated during the f i r s t several years of service.

Hydrogen - - 65.5 gmol

Backfill gas (maximum f i l l q u a n t i t y of He) - - - ~ - - - 41.3 gmol

Alpha decay helium -~ (taken as hydrogen) - - - - - - - ~ - - - 0 gmol

Noble gasses (Kr, Xe) - - (taken as hydrogen)--------- 0 gmol

Oxygen - - (taken as hydrogen) . . . . . . . . . . . . . . . . . . . . . . . 0 gmol

106.8 gmol TOTAL _ . . _ _ . . _ _ _ _ . _ _ _ _ . _ _ _ _ . _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

MCO Operat ing Pressures

7.1.3.1 Based on a 97.4 gmol total gas inventory (see section 7 . 1 . 2 . 1 ) . on a 64'C (337 K ) operating temperature (see section 4.41, and on a 500 L internal void volume (see section 4 . 3 ) . the maximum operating pressure (P,ps,,,,,) required for helium loss calculations i s :

Maximum Pressure For Helium Loss Ca lcu la t ions .

Pupstream= nRT/V = (97.4 gmo1)(0.082 L atm/gmol.K)(337 K ) / 5 0 0 L = 5.38 atm

7.1.3.2 Maximum Pressure For Hydrogen Release C a l c u l a t i o n s . Based on a 106.8 gmol total gas inventory (see section 7 . 1 . 2 . 2 ) , on a 64°C (337 K ) maximum MCO temperature, and on a 500 L minimum MCO void volume, the worst case operating pressure (PupStPe ) required for hydrogen release calculations i s : Pupstream= nRT/V = (106.8 gmo?)(0.082 L atm/gmol K)(337 K)/500 L = 5.90 atm

7.2 DOCUMENTATION AND VALIDATION OF FLOW CORRELATION CALCULATIONS

Appendix A provides spread sheet listings of the calculations t h a t were performed t o predict actual in-service leak rates from leak rate acceptance c r i te r ia . The symbol definitions, equations, and hand calculations provided i n the following sections demonstrate, document, and validate the equations t h a t were i n p u t t o the Excel" program t o produce the spread sheet l is t ings.

7.2.1

listed below, along w i t h definitions for their parameters and references t o the particular sections of Appendix B t h a t govern their application

ANSI N-14.5 D r a f t 1997 J Equations and Guidel ines

The equations recommended by Appendix B of ANSI N-14 5 Draft 1997 J are

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HNF-2155 Rev 1

7.2.1.1 D e f i n i t i o n O f Symbols. The f o l l o w i n g symbols and t h e i r d e f i n i t i o n s a re taken from sec t i on B2 o f ANSI N-14.5 D r a f t 1997 J :

a = leakage h o l e l e n g t h , cm 0 = leakage h o l e diameter. cm

F,= c o e f f i c i e n t o f continuum f l ow conductance per u n i t pressure, cm3/atm.s

F,= c o e f f i c i e n t o f f r e e molecular f l ow conductance per u n i t pressure,

k = r a t i o o f s p e c i f i c heat a t constant pressure t o s p e c i f i c heat a t constant volume

L = vo lumet r i c leakage r a t e , cm3/s

L,= downstream vo lumet r i c leakage r a t e , cm3/s

L,= measured leakage r a t e . cm3/s

L,= re ference a i r leakage r a t e a t standard cond i t i ons o f 25°C and 1 atm abs.

L,= upstream vo lumet r i c leakage r a t e , cm3/s

M = molecular we igh t , g/gmol

P = f l u i d pressure, atm abs

Pa= average stream pressure = 1/2(P,+ P d ) , atm abs

P,= f l u i d downstream pressure, atm abs

PI= p a r t i a l pressure o f one component o f a gas m ix tu re , atm abs

P,= t o t a l pressure o f a gas m ix tu re , atm abs

P,= f l u i d upstream pressure, atm abs

Q = mass - l i ke leakage r a t e , atm.cm3/sec

R,= un i ve rsa l gas constant , 8 .31 x l o 7 erg/gmol . K

R, atm= un i ve rsa l gas constant , 0.082 L .atm/gmol . K

T = f l u i d absolute temperature, K

T,= standard temperature, 298 K

cm3/atm.s

s t d cm3/s

= f l u i d v i s c o s i t y , CP ( cen t ipo i se )

rr = r a t i o o f F, t o F, .dimensionless (no longer used i n t h e 1997 d r a f t s tandard, inc luded on t h e at tached spread sheets f o r i n fo rma t ion )

rs= gas d e n s i t y , g/cm3

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HNF-2155 Rev 1

7.2.1.2 Sect ion B3 (Gas Leakage) o f ANSI N-14.5 1997- J , Appendix B, l i s t s t h e f o l l o w i n g equations and describes t h e i r a p p l i c a t i o n .

(8-1) Q = L*P atm.cm’/s - - A mass- l ike f l o w r a t e .

(8-2) La= (F, + F,,)(P,-P,) cm’ls - - Used t o est imate volume leakage r a t e

(8-3) F,= [2.49x1O6*~]I(ap) c m ’ l a t m . ~ - - and where

(8-4) F,= C3.81~1 O3*d*(TIM)’ 511 (aP, cm’latm. see.

(8-5) L,= (F, + F,,)(Pu-Pd)(PalPu) cm’ls OR id= ( F , f Fm)(Pu-P(i)(PJPd) cm’ls

Basic Flow Equations.

a t t h e average pressure - - where

- used t o express leakage r a t e s i n terms o f upstream o r downstream pressure cond i t i ons , as opposed t o t h e average stream pressure bas i s used by equat ion (8-2).

n n (8-6) P,= i=lI P, ;[6-7) M; i=lt P,M,/P, , and ( 8 - 8 ) Urn= , = l I n p l p , / p r n

- - used t o c a l c u l a t e equiva lent pressure, molecular we igh t , and v i s c o s i t y f o r i d e a l gasses i n terms o f component p r o p e r t i e s o f an n - component m ix tu re weighted by t h e r a t i o o f p a r t i a l t o t o t a l pressure.

7.2.1.3 Hand C a l c u l a t i o n A t Reference Condi t ions. The l e f t hand column of Table 8 . 2 (Upstream Air Leakage for Various HoJe Diameters) o f ANSI N-14.5 D r a f t 1997 J i nc ludes a ca l cu la ted a i r leakage r a t e o f 7.94 x s t d cm31s. The f l o w cond i t i ons and t h e leak r e p o r t i n g bas i s s p e c i f i e d f o r t h e l eak r a t e s l i s t e d on t h e l e f t s i d e o f t h e t a b l e were se lected t o match t h e s tandard ’ s d e f i n i t i o n f o r t h e “ re ference a i r leakage r a t e ” ( L , ) t h a t i s t h e bas i s f o r a l l l eak t e s t acceptance c r i t e r i a under ANSI N-14.5.

The f o l l o w i n g hand c a l c u l a t i o n i s p rov ided t o demonstrate t h e bas i c f l o w equations used t o o b t a i n t h e 7.94 x 1 0 ~ s t d cm3/s f l o w r a t e and t o v a l i d a t e t h e i r implementation i n t h e spread sheet program. The spread sheet l i s t i n g f o r t h i s c a l c u l a t i o n i s prov ided on page 37 ( i n Appendix A o f t h i s document! A l l o f t h e f o l l o w i n g equat ion numbers, t a b l e numbers, e t c . , r e f e r t o Appendix B o f ANSI 8-14.5 D r a f t 1997 J . unless s ta ted otherwise.

Eauation B-3

F,= C 2 . 4 9 ~ 1 0 ~ x D4]l(ap) cm3/atm.s - - where:

a = h o l e l e n g t h = 1 cm ( f rom Table 8 .2 )

D = h o l e diameter = 1 x cm ( f rom Table 8.2)

= v i s c o s i t y o f a i r a t 298 K (25°C) = 0.0185 CP ( f rom Table B . l )

Other than t o make t h a t Note t h a t t h e 2 . 4 9 ~ 1 0 ~ m u l t i p l i e r inc ludes t h e conversion f a c t o r t o ge t

from cen t ipo i se (10~2dyne.seclcm2) t o atm.sec. obse rva t i on , t h i s document w i l l n o t break t h e conversion f a c t o r out o f t h e o v e r a l l m u l t i p l i e r , nor w i l l i t attempt t o c a r r y t h e u n i t s . Th i s a l s o app l i es

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HNF-2155 Rev I

t o s i m i l a r s i t u a t i o n s wi th o the r parameters t h a t occur i n subsequent equat ions. The j u s t i f i c a t i o n f o r t h i s approach i s t h a t t h e purpose o f t h i s s e c t i o n i s t o demonstrate t h a t t h e spread sheet c a l c u l a t i o n s c o r r e c t l y implement t h e ANSI s tandard 's equat ions, as opposed t o v a l i d a t i n g t h e equations themselves .

F,= [2.49x106 ~ ( l x l O ~ ~ c m ) ~ ] / ( l cm)(0.0185 cP) = 1.346 x cm3/atm.s

Eauation 8 -4

F,= [3.81x103 x D3(T/M)' ']/(aP,) cm3/atm.sec. - - where:

T = 298 K ( f rom Table B . 2 )

M = 29.0 g/gmol (From Table B . l )

Pa= average stream pressure = 1/2(P,+ P,) atm abs ( f rom Sect ion 82)

P,= upstream pressure = 1 atm abs ( f rom Table 8.2)

P,= downstream pressure = 0 .01 atm abs ( f rom Table 8 .2 )

F,= C3.81 x103 x ( l ~ l O - ~ c m ) ~ ( 2 9 8 K/29.0 g/gmol)05] / [ ( lcm x 1/2(P,+Pd)1 =

[3.81x1V6 ~ ( 1 0 . 2 7 6 ) ~ 5 ] / [ l / 2 (0 .01 +1.00)1 = [ 3 . 8 1 ~ 1 0 - ~ x 3.2061/[0.5051 =

2.42 X ~ O . ~ cm3/atm.sec

Eauation 8-5

L,= (F, + Fm)(Pu-Pd)(PJPu) cm3/s - - a l l parameters a re l i s t e d above.

L,= (1.346 x +2.42 ~ 1 0 - ~ ) ( 1 . 0 0 -0.01)(0.505/1.00) = 7.94 x10'~crn~/s

Th is r e s u l t e x a c t l y matches t h e leak r a t e l i s t e d i n Table B . 2 , as does t h e va lue f o r L, i n t h e l e f t hand " A i r - Std" column o f t h e spread sheet l i s t i n g on page 37 o f t h i s document ( i n Appendix A ) . I n order t o v e r i f y c o r r e c t implementation o f equations 8-3, 8-4. and 8-5 i n t h e c a l c u l a t i o n s f o r welded MCO's (on t h e r i g h t hand s i d e o f each spread sheet l i s t i n g ) . a 2 x cm h o l e diameter was i n p u t t o t h e spread sheet program. Again, t h e r e s u l t i n g f l o w r a t e f o r upstream pressure cond i t i ons (2.04 x cm3/s) e x a c t l y matched t h a t l i s t e d by Table 8 . 2 f o r t h a t ho le d iameter .

7.2.1.4 c a l c u l a t i o n t o demonstrate t h e general approach used t o c o r r e l a t e leakage r a t e s between d i f f e r e n t cond i t i ons . The h o l e diameters t h a t a r e used f o r t h e MCO l eak c a l c u l a t i o n s (5.81 x l U 4 and 1 .63 x ~ O - ~ cm. r e s p e c t i v e l y ) were obta ined by i t e r a t i n $ t r i a l diameters u n t i l t h e values represent ing t h e l eak t e s t c r i t e r i a (1 x10 and 1 x ~ O ~ ~ scc/s , respec t i ve l y ) appeared a t t h e t o p of t h e two " A i r ( L r ) " columns on pages 38 and 39 ( i n Appendix A ) . Once those were obta ined, t h e spread sheet c a l c u l a t i o n used these h o l e diameters t o o b t a i n t h e values a t t h e t o p o f t h e "He - Test" columns, which p r e d i c t t h e hel ium leak r a t e s t h a t would be observed a t t h e a n t i c i p a t e d l eak t e s t i n g cond i t i ons t h a t correspond t o t h e reference c r i t e r i a . I n t h i s case, t h e o n l y d i f ference i n cond i t i ons i s t h e use o f he l ium ins tead o f a i r .

Hand Calculation At Test Conditions. This s e c t i o n prov ides a hand

24

HNF-2155 Rev I

Sec t ion 84 (Cor re la t ion Between Gas Leakage Rates a t D i f f e r e n t Condi t ions) o f ANSI 6-14.5 D r a f t 1997 J s ta tes ( i n sub-sect ion 6 4 . 1 ) : "Using Equation 8-2 o r Equation B-5. t h e leakage h o l e diameter i s found f o r t h e known cond i t i ons . d iameter , Equation 6-2 o r Equation B-5, and t h e s p e c i f i e d c o n d i t i o n s . Consequently, t h e c o r r e l a t i o n between t h e reference leak (L,) and t h e measured hel ium leak t e s t f l o w i s performed by s imply s u b s t i t u t i n g hel ium parameters f o r those o f a i r i n t h e prev ious c a l c u l a t i o n s (see sec t i on 7 . 2 . 1 . 3 ) .

Eauation 6-3

Leakage i s found a t o the r cond i t i ons us ing t h e ca lcu late!

F,= C2.49x1O6xD41/(ap) cm3/atm.s - - where:

a = h o l e l e n g t h = 1 cm ( f rom Table B.2)

0 = h o l e diameter = 5 .81 x l V 4 cm (see above)

p = v i s c o s i t y o f he l ium a t 298 K (25°C) = 0.0198 CP ( f rom Table B . l )

F,= C 2 . 4 9 ~ 1 0 ~ ~ ( 5 . 8 l x l O ~ ~ c m ) ~ ] / ( l cm)(0.0198 cP) = 1.43 x cm3/atm.s

Eauation 6 -4

F,= [3.81x103 x D3(T/M)' 5]/(aP,) cm3/atm.sec. - - where:

T = 298 K ( f rom Table 6 .2 )

M = 4.0 g/gmol (From Table B . l )

Pa= average stream pressure = 1/2(P,+ P,) atm abs ( f rom Sec t ion B2)

P,= upstream pressure = 1 atm abs ( f rom Table B.2)

P,= downstream pressure = 0 .01 atm abs ( f rom Table B.2)

F,= C3.81 x103 ~ ( 5 . 8 1 x l O - ~ c m ) ~ ( 2 9 8 K/4.0 g/gmol l o 51/ [ ( lcm xl/2(P,+Pd)1 =

C 3 . 8 1 ~ 1 0 ~ x 1 . 9 6 ~ 1 0 . ' ~ x (74 .5 )a51 / [1 /2 (0 ,01 +1.00)1 =

[7 .5x1V7 x 8.631/[0.505] = 1.28 X ~ O . ~ cm3/atm.sec

Eauation 8-5

L,= (F, + Fm)(P,-Pd)(Pa/PJ cm3/s - - a l l parameters a re l i s t e d above.

L,= (1.43 + 1.28 ~ 1 0 - ~ ) ( 1 . 0 0 -0.01)(0.505/1.00) = 1.36 x10Pcm~/s

Th is r e s u l t matches t h e va lue f o r C, i n t h e "He-Test'' column on t h e l e f t s i d e o f t h e spread sheet l i s t i n g on pages 38 and 39 o f t h i s document. The hand c a l c u l a t i o n f o r t h e hel ium r a t e a t t h e maximum acceptance c r i t e r i o n f o r a welded seal (1 xlW7 scc/s) would be i d e n t i c a l , o the r than for t h e sma l le r h o l e s i z e .

No t i ce t h a t t h e increase i n ca l cu la ted f l o w r a t e upon s u b s t i t u t i o n o f

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HNF-2155 Rev 1

hel ium f o r a i r i s o n l y about one t h i r d o f t h e genera l l y accepted r u l e o f thumb, which holds t h a t t h e hel ium f l o w r a t e w i l l be about t w i c e t h a t o f t h e a i r f l o w r a t e . That discrepancy does n o t , however, mean t h a t t h e above c a l c u l a t i o n s a re i n e r r o r . For cond i t i ons t h a t l ead t o c a l c u l a t e d a i r f l ows above 10~7cm3/s . t h e v a l i d i t y o f t h e r u l e decreases as t h e a i r f l o w increases. Consequently, t h e r e i s very l i t t l e d i f f e r e n c e between t h e c a l c u l a t e d f l o w r a t e s f o r a i r and hel ium i n t h e The reason f o r t h i s i s t h a t continuum f l o w dominates i n t h a t reg ion (F/F, = 3 . 2 f o r a i r , and 1.1 f o r he l i um) , whereas t h e r u l e o f thumb app l i es t o fsow on t h e order o f cm3/s o r l e s s , where f r e e molecular f l o w begins t o dominate. This t r e n d i s apparent on cons ide ra t i on o f t h e f l o w ra tes ca l cu la ted f o r a i r ( 1 . 0 x10-’cm3/s) and hel ium (1 .86 x 10~’cm3/s) t h a t appear on t h e r i g h t s i d e o f t h e spread sheet l i s t i n g , where t h e hel ium f l o w r a t e i s about 1 . 9 t imes t h e a i r f l o w r a t e . these cond i t i ons t h e hel ium f l o w i s p l a i n l y i n t h e f r e e molecular regime (F,/F,=O.32) and a i r f l o w i s s p l i t about evenly between them (F,/F,= 0 .91 ) .

7.2.1.5 Hand Calculation A t Operating Conditions. The c a l c u l a t i o n s requ i red t o p r e d i c t l eak r a t e s f o r mix tures o f gases a t a n t i c i p a t e d worst case opera t i ng cond i t i ons a re more complex than those demonstrated i n sec t i ons 7 . 2 . 1 . 3 and 7.2.1.4, which i nvo l ved s i n g l e component gases a t e s s e n t i a l l y ambient cond i t i ons . o u t l i n e d by s e c t i o n 84.1 o f ANSI B-14.5 D r a f t 1997 3 (see s e c t i o n 7 . 2 . 1 . 4 ) . The pr imary d i f f e r e n c e i s t h a t it i s necessary t o c a l c u l a t e composite gas p r o p e r t i e s f o r t h e m ix tu re us ing equat ion 8 -6 . See Appendix A o f t h i s document f o r t h e spread sheet l i s t i n g t h a t was used [by i t e r a t i n g h o l e diameters against r e s u l t i n g values f o r L,] t o e s t a b l i s h t h e equ iva len t s i n g l e - h o l e diameter (5 .81 x standard l eak t e s t r e s u l t (1 x lU5 scc /s ) . The spread sheet l i s t i n g s then go on t o d u p l i c a t e and summarize t h e hand c a l c u l a t i o n s o f sect ions 7 . 2 . 1 . 5 . 1 and 7 . 2 . 1 . 5 . 2 below,

7.2.1.5.1 He1 i um Loss Calculations

Minimum Helium Inven to ry Case From Sect ion 7 . 1 . 2 . 1

s t d cm3/s range.

A t

None t h e l e s s , t h e bas i c approach i s unchanged from t h a t

cm) t h a t would r e s u l t i n t h e s p e c i f i e d maximum

0 Hydrogen (maximum s a f e t y bas is i nven to ry ) ~ - - - - - - - - - ~ - 65.5 gmol 0 B a c k f i l l gas (Minimum Helium Inventory) - - - - - - - - - - - - - - 31 .9 gmol

97.4 gmol 0 TOTAL . _ _ . . _ _ . _ _ . _ _ _ _ _ . _ . _ _ . _ _ . ~ . ~ ~ . ~ ~ . ~ ~ . ~ . . _ _ _ . _ _ _ .

C a l c u l a t i o n o f E f f e c t i v e Molecular Weiqht f o r Gas M ix tu re

(B-6) P,= i=lx P,; bu t (P,/P,) = (gmol component,/gmol mixture,) = mol- f rac, n

n (8-7) M,= i=lI P,M,/P,; from equat ion 8 -6 , M,= i=lznmol-frac,M,

M o l - f r a c H, = 65.5 gmo1/97.4 gmol = 0.6725; and MhydPOgen= 2 g/gmol

Mo l - f rac He = 31.9 gmo1/97.4 gmol = 0.3275; and M,,,,, = 4 g/gmol

M,= 0.6725 x 2 g/gmol + 0.3275 x 4 g/gmol = 1.345 g/gmol + 1.310 g/gmol

= 2.66 q/qmol

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HNF-2155 Rev 1

C a l c u l a t i o n o f E f f e c t i v e V iscos i t y f o r Gas M ix tu re

(8-81 /J,= ,=I ~ n P p l / P m : from equat ion 8-6, p,= i , l ~ n m o l - f r a c y ,

Mo l - f rac H, = 0.6725; and phrdrogen (3 337 K = 0.0096 CP

Mo l - f rac H, = 0.3275: and @ 337 K = 0.0212 CP

pm= 0,6725 x 0.0096 CP + 0.3275 x 0.0212 CP =

0.00646 + 0.00694 = 0.0134 CP

C a l c u l a t i o n o f Leak Rate f o r Gas M ix tu re

(8-3) F,= [2 .49 x 1 0 6 x D41/(ap) cm3/atm.s - - where:

a = h o l e l e n g t h = 1 cm ( f rom Table B.2)

D = h o l e diameter = 5 .81 x 1 0 ~ 4 cm

Note - - The h o l e diameter (0) i s obta ined by i t e r a t i n g t h e h o l e s i z e aga ins t t h e upstream f l ow r a t e (L,) i n t h e f i r s t column o f t h e spread sheet l i s t e d on page 38 o f t h i s document. used f o r D corresponds t o t h e diameter t h a t r e s u l t s i n t h e s p e c i f i e d l eak t e s t c r i t e r i o n (1 x scc/s i n t h i s case) .

pm = v i s c o s i t y o f gas m ix tu re a t 337 K = 0.0134 CP

The f i n a l va lue

F,= [2.49x106 x (5 .81 x ~ m ) ~ ] / ( l cm)(0.0134 cP) =

C 2 . 4 9 ~ 1 0 ~ ~ ~ 1 . 1 4 ~ 1 0 ~ ~ ~ ~ 1 / 0 . 0 1 3 4 = 2.837~10-’/0.0134 =

2.12 x 10.~ cm3/atm.s

(8 -4) F,= C3.81 x l o 3 x D3(T/M)05]/(aP,) cm3/atm.sec. - - where:

T = 337 K ( f rom sec t i on 4 .4 )

M, = 2.66 g/gmol

P, = 5 . 4 atm abs ( f rom sec t i on 7 . 1 . 3 . 1 )

P,= 1 atm abs (MCO leaks a re t o ambient o r near-ambient pressure)

P, = 1/2(P,+ P,) atm abs = 1 / 2 ( 5 . 4 + 1) a t m abs = 3 . 2 atm abs

F,= [3.81x103x(5.81 x 10~4 ~ m ) ~ ( 3 3 7 K / 2 . 6 6 g/gmol)05] / [ ( lcm x 3 . 2 atml=

C(3.81~10~)(1.961~10~’~)(126.7 ) * 51/3.2 = (7.47 x10-’)(11.26)/ 3 . 2 =

2.63 ~ 1 0 . ~ cm3/atm.sec

27

HNF-2155 Rev 1

(B-5) Lu(m,x)= (F, + FJ(PU-P,,)(Pa/Pu) cm3/s - - a l l parameters a re l i s t e d above.

L,(,ix)= (2 .12 x + 2.63 x 1 U 6 ) ( 5 . 4 - 1 .0 ) (3 .2 /5 .4 ) =

(2.38 x 10 cm3/atm.sec)(4.4)(0.593) = 6.21 x cm3/s

C a l c u l a t i o n o f Leak Rate f o r t h e Helium Component o f Gas M ix tu re

From t h e above c a l c u l a t i o n : F = 2 . l Z ~ l O . ~ cm3/atm.s and F,= 2.63 x cm3/atm.sec ( . 2 6 3 ~ 1 6 - ~ cm3/atm.s), such t h a t FJF, = 8 . 1 , which i s t o say t h a t continuum f l o w dominates. Th is , i n t u r n , means t h a t t h e mole f r a c t i o n o f he l ium on t h e downstream s ide o f t h e leak w i l l be e s s e n t i a l l y i d e n t i c a l t o i t s mole f r a c t i o n on t h e upstream s ide . To p u t it another way, t h e hel ium w i l l s imply be swept ou t o f t h e MCO by t h e l eak ing gas m ix tu re :

Lu(he,lm)= Lu(m,x) x mole-frac,, = 6 .21 x cm3/s x 0.3275 = 2.03 x cm3/s

For hel ium. t h e i ssue i s t ime t o minimum acceptable i nven to ry . consequently t h e r e s u l t i s expressed as gmol o f he l ium l o s t per u n i t o f t ime v i a PV = nRT. o r n = PV/RT:

P, = 5 . 4 atm abs

T, = 337 K

R = 0.082 L.atm/gmol . K

LHe(mo,ar)= (L,,(,o,,e,,,,~)(5.4 atm)/ [ (0 .082 L.atm/gmol .K)(337 K ) ] =

(2 .03 x l o 5 cm3/s)(0 001 L/cm3)(5.4 atm)/[27.63 L.atm/gmoll =

3.97 x 10.’ gmol/sec = 3.43 x l o 4 gmollday = 0.125 qmol/vear

7.2.1.5.2 Hydrogen Release Ca lcu la t i ons

Worst Case Gas Inven to ry For Hydroqen Release From Sect ion 7 1 2 2

0

0

Hydrogen - - 65 5 gmol

B a c k f i l l gas (maximum f i l l q u a n t i t y o f He) - - - - - - - 41 3 gmol

106.8 gmol TOTAL ___.____-- ._.__._. ._________._____.__.___.___

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C a l c u l a t i o n o f E f f e c t i v e Molecular Weisht f o r Gas M ix tu re

(5-61 P,= i= l> P,: where (P,/P,) = mol- f rac, n

n (6-7) M,= i=lI P,M,/P,: from equat ion 6 -6 , M,= i=lInmol-frac,M,

Mol - f r a c H, = 65.5gmo1/106.8gmol= 0.6133: and Mhydrogen= 2 g/gmol

M o l - f r a c He = 41.3gmo1/106.8gmol= 0.3867; and Mhellum = 4 g/gmol

M,= 0.6133 x 2 g/gmol + 0.3867 x 4 g/gmol =

1.227 g/gmol + 1.547 g/gmol = 2.77 d s m o l

C a l c u l a t i o n of E f f e c t i v e V i s c o s i t y f o r Gas M ix tu re

(5-8) pm= j = l >'P,p,/P,,,: from equation 6-6, urn= i,l>nrnol - f rac,&

M o l - f r a c H, = 0.6133; and phydrogen @ 337 K = 0.0096 CP

Mo l - f rac He = 0.3867: and p,,,,,, @ 337 K = 0.0212 CP

pm= 0.6033 x 0.0096 CP + 0.3867 x 0.0212 CP =

0.00589 + 0.00820 = 0.01409 CP

C a l c u l a t i o n o f Leak Rate f o r Gas M ix tu re

(5-3) F,= 1 2 . 4 9 ~ 1 0 ~ x D41/(ap) cm3/atm.s - - where:

a = ho le l eng th = 1 cm ( f rom Table 6 .2 ) D = h o l e diameter = 5 .81 x lu4 cm

Note - - The ho le diameter (D) i s obta ined by i t e r a t i n g t h e h o l e Size aga ins t t h e upstream f l o w r a t e (L,) i n t h e f i r s t column of t h e spread sheet l i s t e d on page 39 o f t h i s document. The f i n a l va lue used f o r D corresponds t o t h e diameter t h a t r e s u l t s i n t h e s p e c i f i e d leak t e s t c r i t e r i o n (1 x scc/s i n t h i s case) .

pm = v i s c o s i t y of gas m ix tu re a t 337 K = 0.0141 CP

F,= 1 2 . 4 9 ~ 1 0 ~ x (5 .81 x 1 0 ~ 4 ~ m ) ~ ] / ( l cm)(0.0141 cP) = 2.012 x 1 0 ~ ~ cm3/atm.s

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(8-4) F,= C3.81 x IO3 x D3(T/M)051/(aP,) cm3/atm.sec. - - where:

T = 337 K ( f rom sec t i on 4 . 4 ) M, = 2.77 g/gmol P, = 5 . 9 atm abs ( f rom sec t i on 7 . 1 . 3 . 2 )

P,= 1 atm abs (MCO leaks a re t o ambient o r near-ambient pressure)

P, = 1/2(P,+ P,) atm abs = 1/2(5.9 + 1) atm abs = 3.45 atm abs

F,= C3.81 x103 x (5 .81 x lU4 cmI3(337 K/2.77 g/gmol)051/ [ ( lcm x 3 .45 atm] =

c7.47 x l O ~ ’ x (121.7)051/3.45 = L7.47 x 1 0 ~ 7 x 11.03] /3 .45 =

2.39 x 1 P cm3/atm.sec

(5-5) L,(,,,,= (F, + Fm)(Pu-P,)(Pa/Pu) cm3/s - - a l l parameters a re l i s t e d above

Lu(m,x)= (2.012 ~ 1 0 . ~ + 2.39 ~ l O ~ ~ I ( 5 . 9 - 1 .0 ) (3 .45 /5 .9 ) =

(2 .25 x 10-5)(4.9) (0.585) = 6.45 x ~ O - ~ cm3/s

C a l c u l a t i o n o f Leak Rate f o r t h e Hvdroqen ComDonent o f Gas M ix tu re

From t h e above c a l c u l a t i o n : F,= 2.012 x l U 5 cm3/atm.s. and F,= 2.39 ~ 1 0 . ~ cm3/atm.sec (0.239 x1U5 cm3/atm.s), such t h a t FJF = 3 . 4 2 (i . e . , continuum f l ow dominates). simpyy swept out w i t h t h e o v e r a l l f l o w as a component o f t h e gas m ix tu re (see s e c t i o n 7 . 2 . 1 . 5 . 1 ) :

L,= L,(,,,,x mole-frachydrogen= 6.45 x l v 5 cm3/s x 0.613 = 3.95 ~ 1 0 ~ ~ cm3/s

Consequently t h e hydrogen i s

For hydrogen. t h e i ssue i s t i m e t o maximum acceptable hydrogen concen t ra t i on i n a CSB s torage tube, consequently t h e r e s u l t can e i t h e r be expressed as gmol o f hydrogen released t o t h e tube per u n i t o f t i m e , o r as vo lumet r i c f l o w r a t e a t t h e downstream pressure (L,) and temperature (T,). The spread sheet c a l c u l a t i o n s i nc lude both va lues. Regardless o f whether t h e f low i s expressed i n moles o r l i t e r s , t h e c a l c u l a t i o n f o r t ime t o reach t h e maximum hydrogen concentrat ion l i m i t r equ i res t h a t e i t h e r t h e vo lumet r i c f l o w r a t e from t h e MCO o r t h e molar contents o f t h e tube be co r rec ted t o t h e worst case (maximum) gas temperature w i t h i n t h e tube (Td) . For t h e purposes o f t h i s document. t h a t temperature i s conse rva t i ve l y taken as t h e upstream gas temperature (64’C - - 337 K ) per sec t i on 4 . 4 .

(8-5) Ld(m,x)= (F,+F,)(P,-P,)(P,/P,) = (2.25 x 1 0 ~ 5 ) ( 4 . 9 ) ( 3 . 4 5 / 1 ) =

38.04 x l V 5 cm3/s = 3.80 x 10-4cm3/s a t 337 K

Based on t h e above, t h e hydrogen f l ow i s :

L,= Ld(mlx)~ mole-frac,,,,,,,, = 3.80 x cm3/s x 0.613 = 2.33 x IK4 cm3/s.

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7.3 MAXIMUM STEADY STATE HYDROGEN CONCENTRATION I N CSB TUBES

The hydrogen re lease c a l c u l a t i o n s summarized by t h e spread sheet l i s t i n g on page 39 o f t h i s document conclude t h a t i t would take almost a year f o r t h e hydrogen concen t ra t i on t o reach 1 v o l % within a sealed CSB tube con ta in ing two safety bas i s pressure, mechanical ly sealed MCOs. design prov ides vented tube c losures f o r a l l air-atmosphere tubes. Th is s e c t i o n documents t h e a b i l i t y o f t h e stagnant vent paths t o l i m i t steady s t a t e hydrogen concentrat ions w i t h i n CSB tubes t o acceptable l e v e l s . The goal i s t o demonstrate t h a t t h e hydrogen concentrat ion w i t h i n a worst case tube w i 11 never exceed 1 v o l % hydrogen (25% o f t h e LFL) .

However. t h e c u r r e n t CSB

7 .3 .1 D i l u t i o n by Baromet r ica l l y Induced Breathing

concen t ra t i on t h a t i s ever expected t o occur w i t h i n any CSB tube , based on d i l u t i o n o f hydrogen w i t h i n tubes as a r e s u l t o f " tube b rea th ing " d r i v e n by barometr ic pressure v a r i a t i o n s a lone. barometr ic e f f e c t s because thermal c y c l i n g w i t h i n t h e CSB v a u l t i s n o t considered t o be r e l i a b l e f o r t h i s purpose ( the re i s no guarantee t h a t a l l tubes would be sub jec t t o i t ) .

7.3.1.1 Assumptions. The b rea th ing c a l c u l a t i o n s assume t h a t , even i n t h e case where a p a r t i c u l a r s torage tube payload prov ides l i t t l e o r no heat t o support a v e r t i c a l thermal g rad ien t w i t h i n t h e tube, t h e a i r w i t h i n t h a t s torage tube w i l l be w e l l mixed. Th is assumption i s reasonable i n view of t h e l ong t ime frame requ i red f o r a completely sealed tube t o reach 1 v o l % hydrogen (over t e n months).

These c a l c u l a t i o n s a l s o assume t h a t t h e d i f f e r e n c e between t h e observed 1 .69 atmosphere i n t e g r a t e d annual barometr ic pressure v a r i a t i o n (see s e c t i o n 7 .3 .1 .2 ) and t h e more conservat ive va lue used f o r t h i s c a l c u l a t i o n (1 .25 atmospheres! i s s u f f i c i e n t t o compensate f o r (among o the r t h i n g s ) vo lumet r i c ho ld-up w i t h i n t h e vent paths, which i s ca l cu la ted t o r e q u i r e a 0.01" Hg minimum susta ined change (up o r down) be fo re any subsequent change w i l l r e s u l t i n a n e t movement o f a i r t o o r from t h e s torage tube (see t h e second paragraph o f sec t i on 7 . 3 . 1 . 2 ) .

7.3.1.2 Basis For Air-Exchange Rate. Local barometr ic e f f e c t s have most r e c e n t l y been documented i n Barometric Pressure Var ia t i ons (WHC-EP-0651), which r e p o r t s an i n t e g r a t e d annual barometr ic pressure v a r i a t i o n o f 1 .69 atmospheres (i . e . , tube volumes). Table 6 o f t h a t r e p o r t prov ides minimum, average, and maximum i n t e g r a t e d sho r t - te rm data f o r per iods from one hour t o one yea r . consecut ive days, t h e minimum value i s w i t h i n 75% o f t h e average va lue f o r per iods on t h e order o f one month o r more. For t ime per iods on t h e o rde r o f one yea r , t h e minimum value i s w i t h i n 99% o f t h e average va lue. I n view o f t h e f a c t t h a t t h e worst case c a l c u l a t i o n i n t h i s document p r e d i c t s t h a t a complete ly sealed tube would n o t reach 1 v o l % hydrogen du r ing t h e f i r s t t e n months o f se rv i ce . it should be s u f f i c i e n t l y conservat ive t o base a "b rea th ing al lowance" f o r vented tubes on a va lue t h a t Table 6 [o f WHC-EP-06511 descr ibes as t h e minimum i n t e g r a t e d pressure swing over a pe r iod o f one month o r l e s s . That. t a b l e l i s t s t h e minimum i n t e g r a t e d swing as 2.97 inches o f mercury over a

31

Th is sec t i on ca l cu la tes t h e worst case steady s t a t e hydrogen

Breath ing c a l c u l a t i o n s a re l i m i t e d t o

While d a i l y pressure swings can approach zero f o r severa l

HNF-2155 Rev 1

696 hour pe r iod ( l e s s than one month), which i s equiva lent t o 0.00427 inches of mercury per hour, o r 37.38 inches o f mercury per yea r . A t 29.92 inchs o f mercury per atmosphere, t h i s t r a n s l a t e s t o 37.3W29.92, o r 1 .25 atmospheres pe r y e a r .

F i n a l l y , cons ide ra t i on must be g iven t o t h e e f f e c t s o f ho ld-up w i t h i n t h e t u b e ' s s h i e l d p l u g vent p o r t s . The s h i e l d p l u g i s prov ided w i t h two i d e n t i c a l vent p o r t s , each o f which cons is t s o f a 9 " l ong 3/4" I . D . h o l e bored i n t o t h e s i d e o f t h e s h i e l d p lug a t i t s upper end, and s l a n t i n g upward t o a p o i n t where i t i n t e r s e c t s a 2" deep v e r t i c a l ho le t h a t has been bored i n t o t h e upper face o f t h e s h i e l d p l u g . The v e r t i c a l h o l e i s taped t o rece ive a 2 1/2" l ong , 3 /4 " NPT p i p e n i p p l e . The vent p o r t terminates w i t h a 3 /4 " NPT p i p e coup l i ng and a small s t r a i n e r f i t t i n g ( t h e "breather vent assembly"). Based on a 170 cm3 est imate f o r t h e hold-up volume o f each assembly, a t o t a l ho ld-up volume o f 0 . 4 L should be conservat ive (see sec t i on 4 . 7 f o r t h e volume c a l c u l a t i o n s ) Given a t o t a l n e t s torage tube vo id volume o f 1300 L f o r t h e worst case payload c o n f i g u r a t i o n (again. see sec t i on 4 . 7 ) . t h e 0 . 4 L ho ld-up volume represents on l y about t h r e e hundredths o f 1% ( 3 . 1 x o f t h e worst case minimum tube volume. Consequently, a susta ined barometr ic swing o f 0 .01 inches o f Hg should be more than adequate t o c l e a r t h e p o r t s o f t h e i r 0 . 4 L ho ld-up volume and, thereby. a l l ow any subsequent susta ined swing ( i n e i t h e r d i r e c t i o n ) t o a c t u a l l y t r a n s f e r gas t o o r from t h e s torage tube:

29.92" Hg (equ iva len t t o one tube volume) x 3 . 1 x l U 4 = 0.0093" Hg

Based on a l l o f t h e above, i t should be both reasonable and conserva t i ve t o assume t h a t t h e a i r w i t h i n vented CSB tubes w i l l be exchanged a t l e a s t 1 .25 t imes per y e a r , and t h a t a t l e a s t 10% o f i t w i l l be exchanged pe r month, on average. exchange occu r r i ng , t h e ca l cu la ted worst case d a i l y hydrogen leakage i s so low t h a t any s h o r t term i n t e r r u p t i o n s w i l l no t r e s u l t i n a s i g n i f i c a n t s h o r t term hydrogen bu i 1 d up.

7.3.1.3 Based on a worst case minimum n e t v o i d volume o f 1300 L f o r a CSB tube con ta in ing two mechanical ly sealed MCOs (see s e c t i o n 4 . 7 ) . and based on a worst case maximum hydrogen re lease r a t e o f / . 3 1 x l V 4 gmol/day per MCO (see t h e spread sheet l i s t i n g on page 39 o f t h i s document). t h e f o l l o w i n g ma te r ia l balance equations apply :

And w h i l e i t i s poss ib le t h a t several days may go by w i thou t any

Material Balance Equations.

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HNF-2155 Rev 1

G = Total Gas OUT, grnollyr (as barometric pressure decreases)

= Air IN, gmol/yr (as barometric pressure increases) \I

CSB Tube With Two MCOs .r

H = H2IN,grnol/yr

Figure 7-1: Gas Exchange Through CSB Tube Plug Vents

H = H, I N = Z(7.31 x l V 4 gmollday)(365 day l y r ) = 0.533 gmol ly r (see spread sheet l i s t i n g on page 39 o f t h i s document)

V = 1300 L (see sec t i on 4 .7 )

T = 337 K (see sec t i on 4.4)

N = PV lRT = (1 atm)(1300 L ) l ( . 0 8 2 atm.L/gmol.K)(337 K ) = 47.0 gmol

A = A i r I N (gmo l i y r ) as barometr ic pressure increases

G = To ta l gas OUT (gmol /yr ) as barometr ic pressure decreases

Given a 1 .25 a t m annual i n teg ra ted pressure v a r i a t i o n ,

G = 1.25 N/yr = 58.8 gmol ly r

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HNF-2155 Rev 1

Hvdroqen Balance

In : H. gmol H,/yr

out : Y, G gmol HJyr - - Y, = mole f r a c t i o n H,, G = gmol/yr t o t a l

Accumulation: (PV/RT) dY,/dt = N dY,/dt gmol HJyr ;

N dY,/dt = H - (Y, G) ;

dY,/dt + (G/N)Y, = H/N :

The " i n t e g r a t i n g f a c t o r " = eiGiNdt = eGINt :

eGiN x CdY,/dt + (G/N)Y,l = (H/N) x eGiN ;

I d ( Y , eG" t , = I H / N eGIN d t ;

H H/N(N/G)eGiNt + C ;

@ t = 0, Y, = Y i ;

y eG/N t =

Y, = (N/G) + C :

Y,O =(H/G) + C . C Y," - (H /G)

Y, = (H/G) + [Y," - (H/G)e-G"t] = [Y," eGiN + (1 - e-'" ) H/G1;

As t approaches i n f i n i t y . Y, approaches H/G:

Steadv S t a t e So lu t i on

H = 0.533 gmol H,/yr (see above):

N = 47 .0 gmol (see above) ;

G = 58.8 gmo l l y r (see above);

A t steady s t a t e . Y, = H/G = (0.533 gmo l / y r ) / (58 .8 gmo l l y r ) =

0.0091, o r 0 .9 v o l %

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APPENDIX A: SPREAD SHEET CALCULATIONS

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APPENDIX B: THE NFPA 69 EXPLOSION PREVENTION STANDARD

The s t a t e d purpose o f NFPA 69 i s t,o prevent explosions i n enclosures t h a t con ta in combustible gases, m i s t s . o r dusts . An explos ion i s de f i ned by t h e standard as "The b u r s t i n g o r rup tu re o f an enclosure o r a con ta ine r due t o t h e development o f i n t e r n a l pressure from a d e f l a g r a t i o n . " A d e f l a g r a t i o n i s de f i ned as "Propagation o f a combustion zone a t a v e l o c i t y t h a t i s l e s s than t h e speed o f sound i n t h e unreacted medium." Paragraph 1-1.2 o f t h e standard s p e c i f i c a l l y s ta tes t h a t i t does no t apply t o dev:,ces o r systems designed t o p r o t e c t aga ins t detonat ions, which i t def ines as Propagation o f a combustion zone a t a v e l o c i t y t h a t i s g rea te r than t h e speed o f sound i n t h e unreacted medium." It a l s o excludes, among o the r t h i n g s , unconfined d e f l a g r a t i o n s and t h e design, c o n s t r u c t i o n , and i n s t a l l a t i o n o f d e f l a g r a t i o n ven ts .

The standard recognizes two general classes o f techniques f o r p reven t ing explos ions. based on p reven t ing o r l i m i t i n g damage from combustion.

Four methods a re recognized f o r l i m i t i n g o r prevent ing damage from combustion: containment. 3) spark ex t i ngu ish ing , and 4) i s o l a t i o n . Because hydrogen i s very easy t o i g n i t e over a wide range o f hydrogen and oxygen concentrat ions. and because i t would be very d i f f i c u l t t o demonstrate t h a t a hydrogen burn cou ld n o t r e s u l t i n a de tona t ion , as opposed t o a d e f l a g r a t i o n , none o f these methods appears t o apply (one poss ib le except ion would be t o demonstrate adequate d e f l a g r a t i o n pressure containment, based on a l i m i t e d oxygen concen t ra t i on ~~ see sec t i on 5.1.2.2.1). This i s no t t o say t h a t t h e MCO. sh ipp ing cask, MCO Handling Machine (MHM) cask, o r s torage tube designs w i l l n o t r e q u i r e ana lys i s t o demonstrate c a p a b i l i t y t o w i ths tand a de tona t ion w i t h no unacceptable consequences. However, i f i t were necessary t o per form such an a n a l y s i s , i t would no t be performed t o any requirement o f NFPA 69.

Two methods a re recognized f o r prevent ing combustion: concen t ra t i on reduc t i on , and 2) combustible concentrat ion reduc t i on .

Chapter 2 o f t h e standard covers a p p l i c a t i o n o f t h e ox idan t reduc t i on technique. Paragraph 2 - 7 . 2 prov ides t h e operat ing l i m i t s and ins t rumen ta t i on requirements f o r systems t h a t w i l l be operated below t h e L i m i t i n g Oxidant Concentrat ion (LOC). See sec t i on 5.1.1.1 f o r a d d i t i o n a l d e t a i l regard ing t h e s p e c i f i c ope ra t i ng l i m i t s and inst rumentat ion requirements t h a t a r e invoked by t h e s tandard.

Chapter 3 covers a p p l i c a t i o n o f t h e combusti b l e reduc t i on technique. Paragraph 3-3 prov ides design and opera t i ng requirements f o r systems t h a t w i l l be operated below t h e Lower Flammable L i m i t (LFL). t h a t t h e combustible concen t ra t i on be maintained a t o r below 25% o f t h e LFL (i . e . , 25% o f 4 v o l % f o r hydrogen i n a i r = 1 ~ 0 1 % ) . An except ion i s prov ided t o a l l o w combustible concentrat ions up t o 60% o f t h e LFL f o r systems t h a t have t h e c a p a b i l i t y t o au tomat i ca l l y shut o f f t h e source o f combustible m a t e r i a l o r o therwise prevent a combustion event (automatic a c t i v a t i o n o f quenching systems, e t c . ) by means o f inst rumentat ion w i t h sa fe ty i n t e r l o c k s .

One c lass i s based on combustion prevent ion w h i l e t h e o the r i s

1) d e f l a g r a t i o n suppression, 2) d e f l a g r a t i o n pressure

1) ox idan t

Paragraph 3-3.1 requ i res

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HNF-2155 Rev 1

F i n a l l y , NFPA 69 addresses s i t u a t i o n s where i t i s e i t h e r impossib le or i napprop r ia te t o meet any o r a l l o f t h e d e t a i l e d requirements t h a t It invokes. Paragraph 1-1.3 o f s ta tes t h a t "Nothing i n t h i s standard s h a l l be in tended t o prevent t h e use o f systems. methods, o r devices o f equiva lent or super io r q u a l i t y , s t reng th , f i r e res i s tance , e f fec t i veness , d u r a b i l i t y , and s a f e t y over those p resc r ibed by t h i s s tandard, prov ided techn ica l docurnentati on i s made a v a i l a b l e t o t h e a u t h o r i t y having j u r i s d i c t i o n t o demonstrate equiv!lency and t h e system, method, o r dev ice i s approved f o r t h e in tended purpose.

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APPENDIX C: ALTERNATE CALCULATIONS

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LOSS OF HYDROGEN FROM CSB TUBES V I A DIFFUSION

Whereas t h e c a l c u l a t i o n s and r e s u l t s i n sec t i on 7 . 3 a re based on d i l u t i o n o f hydrogen by ba romet r i ca l l y induced atmospheric b rea th ing a lone, t h e at tached a l t e r n a t e c a l c u l a t i o n i s based on l o s s o f hydrogen from t h e tubes v i a d i f f u s i o n a lone, w i t h no al lowance f o r any mass f l o w o f gas t o o r from t h e tubes. And, whereas t h e c a l c u l a t i o n s i n sec t i on 7 . 3 a r e based on complete m ix ing o f t h e a i r and hydrogen w i t h i n each tube, t h i s a l t e r n a t e c a l c u l a t i o n l i m i t s t h a t assumption t o t h e vo id space between t h e bottom o f t h e tube p l u g and t h e upper sur face o f t h e t o p MCO. A l l o the r v o i d spaces, i n c l u d i n g t h e vent p e n e t r a t i o n s / l i n e s and t h e annular space between t h e bottom o f t h e tube p l u g and t h e bottom o f each vent pene t ra t i on , a re assumed t o be s tagnate. shown on t h e l a s t page o f t h e attached hand w r i t t e n sheets, t h e d i f f u s i o n c a l c u l a t i o n p r e d i c t s t h a t , based on t h e d i f f u s i o n mechanism a lone, t h e maximum steady s t a t e hydrogen concentrat ion w i l l no t exceed 0.7 ~ 0 1 % .

Considering t h a t both mechanisms (breath ing and d i f f u s i o n ) a re shown t o r e s u l t i n maximum steady s t a t e hydrogen concentrat ions t h a t a re w e l l below 1 v o l % ( 0 . 9 ~ 0 1 % . based on b rea th ing alone, and 0 . 7 ~ 0 1 % . based on d i f f u s i o n a lone) along w i t h t h e f a c t t h a t both mechanisms w i l l a c t u a l l y be a c t i v e a t t h e same t i m e , t h e o v e r a l l conc lus ion i s t h a t no vented CSB tube w i l l ever even approach 1 v o l % hydrogen ( l e t a lone t h e 4 vo l% LFL) unless i t conta ins an MCO w i t h a d e f e c t i v e seal

As

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APPENDIX D: INDEPENDENT REVIEW

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HNF-2155 Rev 1

REVIEW CHECKLIST

ocument Reviewed: NF-2155 Rev 1 (ECN 652276) Multi-Canister Overpack Combustible Gas Management Leak Test cceptance Criteria

cope of Review: hole thing

Yes No NA 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0

’ Previous reviews complete and cover analysis, up to scope of this review, with no gaps.

Problem completely defined.

Accident scenarios developed in a clear and logical manner.

Necessary assumptions explicitly stated and supported.

Computer codes and data files documented.

Data used in calculations explicitly stated in document.

-

Data checked for consistency with original source information as applicable. - Mathematical derivation checked including dimensional consistency of results.

Models appropriate and used within range of validity or use outside range of established validity justified. Hand calculations checked for errors. Spreadsheet results should be treated exactly the same as hand calculations. Software input correct and consistent with document reviewed.

Software output consistent with input and with results reported in document reviewed.

Limitslcriteriatguidelines applied to analysis results are appropriate and referenced. Limitslcriterialguidelines checked against references. Safety margins consistent with good engineering practices.

Conclusions consistent with analytical results and applicable limits.

Results and conclusions address all points required in the problem statement.

Format consistent with appropriate NRC Regulatory Guide or other standards.

Review calculations, comments, andlor notes are attached.

Document approved.

*

2 / 1 6 / 9 9 Date

Paul Rittmann Reviewer (Printed Name and Signature)

*Any CalCUlatiOnS, comments, or notes generated as part of this review should be signed, dated and attached to this checklist. Such material should be labeled and recorded in such a manner as to be intelligible to a technically qualified third party.

A-6002-359 (02/98)

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APPENDIX E: REFERENCES

ANSI N14.5, 1987, American National Standard For Radioactive Mater ia ls - - leakage tes ts on packages fo r shipment, American Nat ional Standards I n s t i t u t e , I n c . , New York, N Y .

ANSI N14.5. 1997, American National Standard For Radioactive Mater ia ls - - leakage tes ts on packages f o r shipment - - Draf t J , American Nat ional Standards I n s t i t u t e , I n c . , New York, N Y .

P ro tec t i on Associat ion.

Following a Loss-of-Coolant Accident, NRC Regulatory Guide 1 . 7 . U . S . Nuclear Regulatory Commi ss ion , Washington, D . C .

HNF-1719, D r a f t Rev 0, Canister Storage Bu i ld ing Process Technical Manua 1 , COGEMA Engineering Corporat i on, R i ch l and, WA, 1998.

HNF-SD-SNF-TI-040. Rev 3 , MCO In te rna l Gas Composition and Pressure During I n t e r i m Storage, DE&S Hanford I n c . , Rich land, WA, 1997.

HNF-SD-SNF-RD-007, SNF Canister Storage Bu i ld ing and Hot Condi t ioning System StandardslRequirements I d e n t i f i c a t i o n Document, DE&S Hanford I n c . , Rich land, WA. 1997.

HNF-SO-OCD-001, D r a f t Rev. 4, Spent Nuclear Fuel Project Product Spec i f i ca t ion . DE&S Hanford I n c . , Richland, WA, 1997.

HNF-S-0426, Rev. 5 , Performance Spec i f i ca t ion fo r the Spent Nuclear Fuel Mult i -Canister Overpack, DE&S Hanford I n c . , Rich land. WA, 1997.

HNF-SD-TP-SARP-017. Rev. 1 Safety Analysis Report f o r Packaging (Onsi te) Mu l t i -can is te r Overpack Cask, DE&S Hanford I n c . . Rich land, WA, 1997.

PNNL-11471, Hanford S i t e Climatological Data Sumary 1996 With H i s t o r i c a l Data. P a c i f i c Northwest Nat ional Laboratory , (1996).

WHC-EP-0651, Barometric Pressure Var iat ions. Westinghouse Hanford Company. Rich land WA, 1993.

WHC-SD-SNF-TRP-018, Test Report For M u l t i p l e Canister Overpack Mechanical Closure Prototype Test ing. Rust Federal Services o f Hanford. I n c . , Rich land, WA. 1996.

S c o t t Spec ia l t y Gases, Scott Special ty Gases ca ta log , Sco t t Environmental Technology I n c . , P lumsteadvi l le . PA, 1985.

Wel ty , James R . . Charles E . Wicks..and , Robert E . Wilson, Fundamentals of Momentum, Heat and Mass Transfer, John Wiley & Sons, I n c . New York, N Y , 1969.

NFPA 69, 1997, Standard on Explosion Prevention Systems, Nat ional F i r e

NRC. 1978. Control o f Combustible Gas Concentrations i n Containment

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P r o j e c t T i t l e /Work Order Mu1 ti -Cani s t e r Overpack Combustible Gas Management Leak Tes t Acceptance C r i t e r i a . Rev 1

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1.EClY 6522 ENGINEERING CHANGE NOTICE P.pa 1o'a/67531/metadc717854/...HNF-2155 Rev 0, All Sheets I NIA Design AuthorityICog Engineer Signature & Date 5. Date 2/11/99 8.Approval Designator