Embed Size (px)
Citation preview
:.?C o M 195
NRC
U.S. NUCLEA\ riLGULATO1t AMISSION
DISTRIBUTION OIn PART 50 DOCKET MATERIAL
DOCKET NUMO)IEH
FILL NUMBER
T Mr SFRIOM: Northern States Pwr Company DATE OF DOCUMENT
Minneapolis, Mn 5-10-76
L 0 Mayer DATE RECEIVED 5-12-76
ILETTER [)NOTORIZED PROP INPUT FORM NUMBER OF COPIES RECEIVED
IWORIGINAL NUNCLASSIFIED OcoPv one signed
DE CRIPTION ENCLOSURE Etr re GE ltr to NRC dtd 1-b-76... trans the !
following: Information concerning In-Plant.Safety Rel&ef testing......(40 cys encl rec'd)
PLANT NAME: Monticello
SAFETY FOR ACTION/INFORMATION ENVIRO 5-14-76 ehf ASSIGNED AD: ASSIGNED AD BRANCH CHIEF ,__, __ j BRANCH CHIEF _
___ROJECT MA-NAGER:*. j PROJECT MANAGER _
LIC. ASST : /},5 L LIC. ASST.
INTERNAL DISTRIBUTION
FIL SYSTEMS SAFETY PTA Nt SYSTFMS.EvTun wr NRC PDR HETNEMAN TEDESCO ERNST jI I&E -" . SCUOEDLR _ BENAROYA BALLARD OELDLAINAS SPANGLER
~-4ICGOSSICK & STAFF ENGINEERING IPPOLITO . MTPC MCCARY _ SITE TECH
CASE KNIGHT OPERATING REACTORS GAl1ILL
H1ANAUER SIiWJEIL STELLO STEPP .ARLESS PAWLICKI O A TC t1F'ilkAN
OPE-'RATING TECHT FPROJECT BOYD
IANAGEMENT
P . COLLINS
HOUSTON
PETERSON ____01
MELTZ
IIELTE1ES SKOVH1OLT
--- I - ______ __________________ _______________
REACTOR SAFETY ROSSNOVAK
ROSZTOCZY
CIIECK
4-4-- +--
AT & SAL.TZ
EXrT:liN
InnLPR:fie to6/<; / NATL
SB TIC REG.
ASLI--CONSU
/4,'- 4-
/
/
I M AN
AL D)ISTRIIUUIN
LAB FILTA NTS
-Lo ) r
EISENH UT SI AO BAE R SCIRWENCER GRI'ES
SITE SAFETY & ENVIRC ANALYSIS DENTON & NJTJ.ER
HIROOK!AVi'N NATL TAB ULRIKSON (ONL)
'11 ___ ________
SITE ANALYSIS VOLLMER
BUNCH
J. COLLINS KREGER
C 10OL N UMN1BE -R
NORTHERN STATES POWER COMPANY
MINNEAPOLIS, MINNESOTA 55401
May 10, 1976
Mr Victor Stello, Director Division of Operating Reactors U S Nuclear Regulatory Commission Washington, DC 20555
Dear Mr Stello:
MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22
In-Plant Safety Relief Valve Test
The January 6, 1976 General Electric letter from Mr Ivan F Stuart to Mr R S Boyd, U S Nuclear Regulatory Commission described an In-Plant Safety/Relief Valve Test to be conducted as part of the long term program for evaluation of Mark I containment systems.
Northern States Power Company has agreed to the performance of this test at the Monticello Nuclear Generating Plant. Instrumentation essentially as described for purposes of this test has been installed at the Monticello Plant. We now anticipate this test will be completed during the week of May 23, 1976. In order to obtain meaningful information with respect to the test objectives, the testing must be performed under conditions wherein the pressure between drywell and torus is equalized. Present test plans indicate that containment pressure equalization will be required for approximately four days for the conduct of the test. The pressure differential will be restored after completion of the test. If the test sequence is interrupted for scheduled periods in excess of 24 hours, the differential pressure will be restored during the interruption.
Our February 6, 1976 letter to you provided the basis for continued Monticello operation with respect to results of the short term program then available; this letter briefly described certain structural modifications being considered. Based on further information and evaluation, and in view of the longer interval required for implementation of structural improvements, Mark I owners met with you in Bethesda on February 26 to discuss operational measures which could be instituted promptly to enhance safety margins by reducing potential loads. Mr Rusche's letter of February 27, 1976 summarized that meeting wherein Mark I onwers agreed to establish at least a one psi differential pressure between drywell and torus. Our March 1, 1976 letter to you confirmed that NSP would establish and maintain this differential pressure at the Monticello Plant until other appropriate measures could be instituted.
47SI
NORTHERN STATES POWER COMPANY
Mr Victor Stello -2- May 10, 1976
The structural modifications were discussed in further detail with your technical staff on April 9, 1976. These modifications and their evaluation are represented in detail in the attachment to this letter. These modifications will be completed prior to equalizing the containment pressure differential for performing the safety relief valve test.
Information in the attachment shows that safety margins with the modifications installed and the differential pressure removed for the conduct of the test are actually enhanced in comparison to pre-existing conditions with differential pressure prior to any modifications of the structure. Further, conditions under which the test is to be performed will provide safety margins conservatively within and consistent with the margins of safety discussed in Mr Rusche's letter of February 27, 1976.
In summary, the test is currently scheduled for the week of May 23, 1976. The structural modifications will be completed prior to performing the test. Containment differential pressure will be restored after completion of the test.
Yours very truly,
L 0 Mayer, PE Manager, Nuclear Support Services
LOM/LLT/deb
cc: J G Keppler G Charnoff MPCA
Attn: J W Ferman
ATTACHMENT
Our February 6, 1976 letter stated that NSP had undertaken a course of action to "develop detailed engineering designs and determine the feasibility of installation of these designs for modifications to improve the structural elements of the torus support system that are subject to high loadings". We further stated that NSP was prepared to discuss this action plan at NRC convenience.
On April 9, 1976 these modifications were discussed in a preliminary way with NRC Staff personnel. The attached documentation, consisting of drawings and tables, was presented in that discussion. The modifications described by these documents are currently in progress with completion anticipated on or before May 21, 1976.
The table entitled "Summary-Downward Loading Phase", illustrates the substantial improvement in safety margins resulting from these modifications. The ratios of load to ultimate capacity show that the modifications produce a 46% improvement in margins without drywell pressurization over the pre-existing condition with drywell pressurization. A similar comparison for up-loads shows an improvement in margins in excess of 100%
These modifications represent completion of the action plan discussed in our February 6, 1976 letter.
UNITED STATES NUCLEAR REGULATORY COMMISSION
NORTHERN STATES POWER COMPANY
MONTICELLO NUCLEAR GENERATING PLANT
Docket No. 50-263
License No. DPR-22
LETTER DATED MAY 10, 1976 RESPONDING TO NRC REQUESTS
FOR INFORMATION ON CONTAINNENT DESIGN
Northern States Power Company, a Minnesota corporation, by this letter dated May 10, 1976 hereby submits information in response to NRC requests for information concerning the Mark I Containment.
This request contains no restricted or other defense information.
NORTHERN STATES POWER COMPANY
L J 4dchter Vice President, Power Production
& System Operation
On this 10thday of May 1976, before me a notary public in and for said County, personally appeared L J Wachter, Vice President, Power Production and System Operation, and being first duly sworn acknowledged that he is authorized to execute this document on behalf of Northern States Power Company, that he knows the contents thereof and that to the best of his knowledge, information and belief, the statements made in it are true and that it is not interposed for delay.
~K&~Ld2)
DENISE E. BRANALI NOTARY PUBUC -MINNESOTA
NENNEPIN -COUNTY My Commission Expires Oct. 10, 1981
NSP-01-052
4! 917r,
I.D.
COFIGE 3.1 -1 MOiNTICELLO coMPOSITE SaCTMG TPROUSi ';UPPPWESS!Oil NI Br!
3.6
nutech
NSP-01- 052~
'fr
leo -7as.0 pip
C, PIPE SOHI 140'
EXISTING 895 pip=
INTFERMITTENT WELD
COLUMN REINFORCEMENT
Figure 4.1-1
4.3
0
nutech
PIPE COLUMN
CO!0 sU Vm N P IN C ON 1ENTcGN
FBEIN FORCEMavENT
Figure 4.2-1
4.6 flu itarh
INSP-Ui -U. z
TABLE 6.0-1
MATERIAL PROPERTIES
Pins
'Existing Pipe Columns
Pin Connection Clevis
Column Reinforcement
Existing Anchors
Reinforcement Anchors
Pin Support Cradles
Pin Support Wedges
Anchor Plate Washers -
C-1018
API-5LX-GR X42
A-283-GR C
A-106-GR B
A-36
A-615-GR 75
A-516-GR 70
A-516-GR 70
A-36
nutech6.2
0
MINIMUM YIELD MINIMUM ULTIMATE MATERIAL STRENGTH (ksi) TENSILE STRENGTH
C-1018 40 60
A-106-GR B 35 60
A-36 36 58
A-283-GR C 30 55
A-615-GR 75 .75 100
A-516-GR 70 38 70
.API-SLX-GR X42 42 60
A~.
0
TABLE 6.0-2
ACTUAL COLUMN
MATERIAL PROPERTIES
Column material is API-SLX-GR X42
9
No4rkul UJL
nutech6.3
Column Yield Strength Ultimate Strength (ksi) (ksi)
Inside 43.1 73.2
Outside 50.5 82.5
V
NSP-0l-052
the design reports for all Mark I plants. It was
concluded that an across the board value of 0.80"
would be reasonable for all plants.
Using the Bechtel method but utilizing the actual yield
strength of the materials vs. the minimum specified yield.,
and utilizing a preliminary plant unique analysis to arrive
at an upper bound for the column eccentricity (6), the
following values for the ultimate column capacities can be
computed.
Estimated Ultimate Column Capacity (kips)
Inside - Existing 889.
Inside - Reinforced 1606.
Outside - Existing 1282.
Outside -Reinforced 1753..
TABLE.6.1-1
COLUMN ULTIMATE CAPACITIES
Upward load ultimate capacity is.presented in Table 7.2-1.
The capacity is the column cross-sectioned area times the
material ultimate tensile strength. Actual material proper
ties of the existing material is used. Upward load capacity
is controlled by the strength of the pin/lug base connection.
Refer to section 6.3.
nutech 6.5
i VP NSP-01-0S2
P
Figure 6.2-3
EXAGGERATED COLUMN DEFORMATION
K--
From Figure 6.2-3 above, the following categorization of
stresses can be made:
Stresses Resulting From Category
-P-s (axial load) Cosa
x 6 (bending along Primary cost the column)
M (bending moment Secondary at top of column)
Table 6.2-1
CATEGORIZATION OF COLUMN STRESSES
6.9 nutech
Primary
A~RA /(IN9 S. IN'
TAB LE 6.2-2
COLUMN PROPERTIES I
.
. ?(IN) Y/~r Fa ,K51__________ I
p 'exI ry I xx I I
X4Y AXIS Y-Y A 15 AOUT X-X AXI5 Y-Y AX5 WITh WIT1H WITH vnTHWIfwn- W1i U EM1T- VD IT- W w - wMTW- viIU- WiTVH- mE.I OUT OUT
OLIN I& ,RIN. OUT RE;4 CUT REM~. OUT WII A M I OUT Will OUT WII REIN. REN ZEM. YA . OUT Fix FIX COL. REI . - IN ? E.
API S-NCMONT 51*D. CQP B2G10-Z3.a 1 o G-25,280 53
521...44 410 1005. 2.7Z 3.25 2.72 S.0c 80).5 29.S4 24.-G9254 2G.75 0.6 2O.CE9.53 IG4.6 23V,7 28.0 2
42.0 - - - -
API SAI0 MONT 5TD. Ci R 8 -7 51.X R3.30 58.50 494 82.1 2,GI 2.GG 2.G1 3.5010.39.9 39,26 39.93 297 O.G 22,01 18.G9 89.84 93.21 28.0 23.] O. S. 4] 4I
L 2.0, BS.0I
[1] [2] [3] [4] [5] [bl U7] [8l1 D) 101 111 121 8131 04]- [15 [lb] 011 [1B] [19] [20 [21] [22] [23]
'* GEOMETRY ANALYZED
INSIDE SUPPORT
0 "3
OUTslo SUPPORT
Y
1'Y
I - ( ) Sy
S3(K2/r) (K(Q/r) .3 8< -
2Tr2E
23(K /1K)
M~AT'L l0.
z
CD mJ!Y
r, , r6 sy
TABLE to.2-4 EVALUATIDN OF [UATIONAPPENDIX XVII OF SUB5E6TilN NA, ASME
LPRIMARY STRE5ES)SECTION 1T
O - VALUE FROM CORR.ESPONDIM6 eOLUMM INTAFLE 6.2-3
[ I- VALUE FROM o0RESPOWlN6 cOLUMN IM TABLE 4.2-2
(20) O
OLUMNS' V l wITH OT 6 1:' WIl H 6P = P_
5IL U(TC FIX 11nR SteacT Fi Wmical V Fnt VllT \WIT TROT FMI
- + +++
.65Y [22_ 5] [523] 65y 2 .b ]
MONTICELLO (.43 0.79 [O O,59
I.S.
Z35 0.86 102 0.7 0.3S.
C.,
z cI~
C,
C U,
.
NSP-01-052
TABLE 6.3-1.
PIN CONNECTION CAPACITY CRITERIA
6.18
TYPE OF STRESS CODE ALLOWABLE ULTIMATE
Tension at Pin Holes 0.45 F 1.0 F
Shear 0.4 F Fu/-F3
Bearing 0.9 F 1.0 F
Bending 0.75 F 1.0 F
nutech
* NSP-01-052
TABLE 6.3-2
PIN CONNECTION PROPERTIES
ITEM
Bearing Area
Pin Section Mod.
Pin Cross-Sect. Area
*Clevis Tensile Area
*Clevis Shear Area
EXISTING
15.00 in2
12.27 in3
REINFORCED
36.77 in2
12.27 in3
*See Figure 6.3-1 for failure planes
6.19
0
nutech
19.63 in 2 19.63 in2
11.82 in 2 11.82 in2
13.26 in12 13.26 in2
NSP-91i-')5?
N
TABLE 6.3-3
PIN CAPACITY
nutech6.20
(loads in kips)
CODE ALLOW: ULTIMATE CAPACITY STRESSES CAPACITY
TYPE OF w/o Fix w/Fix w/o Fix w/Fix STRESS
Bearing 907 2584 446 1265
Bending 1000 N/A 500 N/A
Shear 1496 N/A 691 N/A
INS P -f11.S *2
TABLE 6.3-4
CLEVIS UPLIFT CAPACITY
(loads in kips)
TYPE OF ULTIMATE CODE ALLOWABLE STRESS CAPACITY STRESS CAPACITY
Bearing 907 446
Tension 650 176
Shear 463 175
6.21 nutech
NSP-01-052
Figure 6.3-1
CLEVIS FAILURE PLANES
-SHEAR FAfLURE PLANE
-TENSILE PATLU2R PLANE .
0
t
1.
Ii,
6.22 nutech
NSP-01 -052
FIGURE 6.S-1
COLUMN CONNECTION
6.25 nUtech
V
TABLE 7.1-1 SUMMARY- DOWNWARD LOADING PHASE.
tLOADIN6 f1J KIF5)1 2 3 4 5 1t 13 14 15 I 1 '11 1I
DEAD SEIS- DYN1MIC TOTAL-LOAD CODE ALLOW. RATIOS OF LOAD TO CAPACITY D CL O ULITIMATE R LOAD MIC POOL SWELL @ POOL CASIYTS
WATER LOAD LOADS SWELL CAPACITY CAPTY ULTIMATE CODE ALLOWADLE ITEM_ +_____ A
ITM +VERT WIT -WITH- R STEEL WITH- WITH WIH- WITH WIH WITH WITH- WITH *WITHOUT AP WITH AP WITHOUT AP WITH AP K +PRT OI U OUT OUT OUT ___ __ OPERAT* HORIZ OUT AP AP AP STRUCT STRUCTSTRUCT STRUCT WITH- WITH WITH- WITH WITH- WITH WITH- WITH COND. tiP I PSI Z23,4 22.3,5 FIX FIX FIX FIX OUT FIX FIX OUT FIX FIX OUT FIX FIX OUT FIX FIX
I.S. 135 1& 727 0 1'& 561 889 IGO 501 92G .84 .46 .G3 .5 1)0 .80 1.12 1I COL
2 I.S. .135 1 7Z7 509 741o 5tof 901 2 44 44b I2G .2 .29 .62 .22 I.&7 .59 1.26 .44 PINjI)G
'.S. 3 SHELL 165 16 727 509 146 5t1 25G8 2F08 7G' 7G:- .29 .29 .22 .22 .98 *S6 .73 73
CONN.
0.5. 6 PIN/L 20 9 62Z 912 690 907 2=5 44b 1269 1.oI .5 .1& .27 2.05 .772 1,54 ,54
0.s. 7 SHELL &, -0 S9 (,22 912 befb 25G5 2508 705 765 .BG .% .27 .27 J.19 .1, .90 .90
0 CONN.
- ------------------D-----------------------------------------------------
I
.I.
SABLE 7.2-1 I(RA77W /W SUMMARY UPWARD LOADING PHASE ,45006/1C P &/D
1?2 3 5- 1 1213 t 15 1i 11 i n
DEAD SEIS- DYNAMIC TOTAL- LOAD ULITIMATE CODE ALLOW. RATIOS OF LOAD TO CAPACITY R LOAD MIC POOL SWELL Q POOL CAAIY STRESS E
WATER L OD LOADS SWELL CAPACITY CAASY ULTIMATE CODE ALLOWABLE M ITEM + R
ITM + VERT W TH- -R.- -A
STEEL V WITH- WITH W WITH WH WITH WITH- WITH WITHOUTAP WITH AP WITHOUT AP WITH AP STEELT + WITH AIP OUT WITHOU OUT OPERAT. HORIZ OUT p P STRUCT STRUCTSTRIT TRUCT WITH- WITH WITH- WITH WITH- WITH WITH- WITH COND. AP I PSI 22,3,4 12,35 FIX FIX FIX FIX OUT FIX FIX OUT FIX FIX OUT FIX FIX OUT FIX FIX
1 135 1 Ito 319 1 200 0 ol 1926 1376 bl1 110b3 .10 .ob .o3 .05 .29 .17 .24 .14
I. S. 2 PIN(UGs) 1 (o 31942 041 00 ibi 4b3 4b3 175 175 .43 .43 .35 .35 1.14 1.14 .92 .921
I.S. 3 SHELL 1351 o 3191 2801 200 Ibi 2568 25$Z 7G5 765 .05 .08 .oe ,OG .26 2G .21 .21
CONN.
ANCs 1551 i&4 sl94 ,2604 200 1&1 190 1220 t7 27 1.11 .?2 .69 .26 2.99 .70 2.40 .6
0.QS. 1 '5 20 509f 343) 244 \9b 2542 9864 1044 i'53 09 .Ob .07 .5 .23 .16 .)9 .15
COL
0.S.
SHELL o zoi %5y 4 244 190 25G8 215-. 765 705 .0 10 .05 .OS ,B2 .32 .26 .2G
CONN.
-S 11L9 wi s &qi -34 S4 19D 100 1620 bi 101 -1.315 .59 1,10, Sl 364 85 2.'M .29
*ANC
4k
C I.
C
