NES 124 Part 4 Requirements for Shielding Materials for Nuclear Purposes

Ministry of Defence Defence Standard 02-124 (NES 124)

Issue 1 Publication Date 01 April 2000

Incorporating NES 124 Category 2

Issue 2 Publication Date June 1990

Requirements For Shielding MaterialsFor Nuclear Purposes

Part 4Low Density Polythene Sheeting

DStan

DStan is now the publishing authority for all Maritime Standards (formerly NESs). Any reference to any other publishing authority throughout this standard should be ignored. Any queries regarding this or any other Defence Standard should be referred to the DStan Helpdesk as detailed at the back of this document.

AMENDMENT RECORD

Amd No Date Text Affected Signature and Date

REVISION NOTE

This standard is raised to Issue 1 to update its content.

HISTORICAL RECORD

This standard supersedes the following:

Naval Engineering Standard (NES) 124 Part 4 Issue 2 dated June 1990.

Ministry of Defence

Naval Engineering Standard

NES 124 Part 4 Issue 2 (Reformatted) June 1990

REQUIREMENTS FOR SHIELDING MATERIALSFOR NUCLEAR PURPOSES

PART 4

LOW DENSITY POLYTHENE SHEETING

This NES Supersedes

NES 124 PART 4 ISSUE 1DG SHIPS 5900

Record of Amendments

AMDT INSERTED BY DATE

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2

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5

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NAVAL ENGINEERING STANDARD 124

REQUIREMENTS FOR SHIELDING MATERIALS

FOR NUCLEAR PURPOSES

PART 4

ISSUE 2 (REFORMATTED)

LOW DENSITY POLYTHENE SHEETING

The issue and use of this Standard

is authorized for use in MOD contracts

by MOD(PE) Sea Systems and

the Naval Support Command

ECROWN COPYRIGHT

Published by:

Director of Naval ArchitectureProcurement Executive, Ministry of DefenceFoxhill, Bath BA1 5AB

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NES 124Part 4

Issue 2 (Reformatted)

iii

SCOPE

1. This NES applies to low density polythene sheeting for use in the reactor shielding of nuclearpropulsion units, and covers both Type A—Virgin polythene and Type B—Boronatedpolythene.

NES 124Part 4Issue 2 (Reformatted)

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NES 124Part 4


v

FOREWORD

Sponsorship

1. ThisNaval Engineering Standard (NES) is sponsored by theProcurement Executive, Ministryof Defence, Chief Naval Architect (CNA), Section NA 113.

2. It is to be applied as required to any Ministry of Defence contract for shielding materials fornuclear purposes and is applicable to Surface Ships and Submarines.

3. This NES comprises:Requirements for Shielding Materials for Nuclear Purposes

Part 1 Cast Lead and Steel Plate Assemblies

Part 2 Lead Slabs, Sheet, Filler Rods and Wool

Part 3 Solder

Part 4 Low Density Polythene Sheeting

4. If it is found to be technically unsuitable for any particular requirement the Sponsor is to beinformed in writing of the circumstances with a copy to Section NA 145.

5. Any user of this NES in MOD or industry may propose an amendment to it. Proposals foramendments which are:

a. not directly applicable to a particular contract are to be made to the Sponsor of the NES.

b. directly applicable to a particular contract are to be dealt with using existing proceduresor as specified in the contract.

6. No alteration is to be made to this NES except by the issue of a formal amendment.

7. Unless otherwise stated, reference in this NES to approval, approved, authorized or similarterms means by the Ministry of Defence.

8. Any significant amendments that may be made to this NES at a later date will be indicatedby a vertical sideline. Deletions will be indicated by 000 appearing at the end of the lineinterval.

9. This NES has been reissued as a result of a general review and update of the contents.

Conditions of Release

General

10. This Naval Engineering Standard (NES) has been prepared for the use of the Crown and ofits contractors in the execution of contracts for the Crown. The Crown hereby excludes allliability (other than liability for death or personal injury) whatsoever and howsoever arising(including but without limitation, negligence on the part of the Crown, its servants or agents)for any loss or damage however caused where the NES is used for any other purpose.

11. This document is Crown Copyright and the information herein may be subject to Crown orthird party rights. It is not to be released, reproduced or published without written permissionof the MOD.


vi

12. The Crown reserves the right to amend or modify the contents of this NES without consultingor informing any holder.

MOD Tender or Contract Process

13. ThisNES is the property of the Crown and unless otherwise authorized in writing by theMODmust be returned on completion of the contract, or submission of the tender, in connectionwith which it is issued.

14. When this NES is used in connection with aMOD tender or contract, the user is to ensure thathe is in possession of the appropriate version of each document, including related documents,relevant to each particular tender or contract. Enquiries in this connection may be made ofthe local MOD(PE) Quality Assurance Representative or the Authority named in the tenderor contract.

15. When NES are incorporated into MOD contracts, users are responsible for their correctapplication and for complying with contracts and any other statutory requirements.Compliance with an NES does not of itself confer immunity from legal obligations.

Related Documents

16. In the tender and procurement processes the related documents listed in each section andAnnex A can be obtained as follows:

a. British Standards British Standards Institution,389 Chiswick High Road,London W4 4AL

b. Defence Standards Directorate of Standardization and Safety Policy,Stan 1, Kentigern House, 65 Brown Street,Glasgow G2 8EX

c. Naval Engineering Standards CSE3a, CSE Llangennech, Llanelli,Dyfed SA14 8YP

d. Other documents Tender or Contract Sponsor to advise.

Note: Tender or Contract Sponsor can advise in cases of difficulty.

17. All applications to Ministry Establishments for related documents are to quote the relevantMOD Invitation to Tender or Contract Number and date, together with the sponsoringDirectorate and the Tender or Contract Sponsor.

18. Prime Contractors are responsible for supplying their subcontractors with relevantdocumentation, including specifications, standards and drawings.

Health and Safety

Warning

19. ThisNESmay call for the use of processes, substances and/or procedures thatmay be injuriousto health if adequate precautions are not taken. It refers only to technical suitability and inno way absolves either the supplier or the user from statutory obligations relating to healthand safety at any stage of manufacture or use. Where attention is drawn to hazards, thosequoted may not necessarily be exhaustive.

NES 124Part 4


vii

CONTENTSPage No

TITLE PAGE i. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SCOPE iii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FOREWORD v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sponsorship v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Conditions of Release v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General v. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .MOD Tender or Contract Process vi. . . . . . . . . . . . . . . . . . . . . . . . . .

Related Documents vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Health and Safety vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Warning vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTENTS vii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 1. MATERIALS 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.1 Chemical Composition 1.1. . . . . . . . . . . . . . . . . . . . . . . .1.2 Quality of Materials 1.1. . . . . . . . . . . . . . . . . . . . . . . . . .1.2.1 Polythene 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.2.2 Boron Carbide 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 2. MANUFACTURE 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .2.1 Method 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.2 Dimensions and Dimensional Tolerances 2.1. . . . . . . . .2.3 Freedom from Defects 2.1. . . . . . . . . . . . . . . . . . . . . . . .

SECTION 3. TESTS 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.1 Visual and X-Ray Fluoroscopy Examination 3.1. . . . . .3.2 Density 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3.3 Hydrogen Density 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . .3.4 Boron Content of Type B Sheeting Only 3.1. . . . . . . . .3.5 Antioxidant Content 3.1. . . . . . . . . . . . . . . . . . . . . . . . . .3.6 Re-tests 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 4. IDENTIFICATION AND PACKAGING 4.1. . . . . . . . .

ANNEX A. RELATED DOCUMENTS A.1. . . . . . . . . . . . . . . . . . . .

ANNEX B. DEFINITIONS AND ABBREVIATIONS B.1. . . . . . . .

ANNEX C. SUGGESTED METHOD FOR THEDETERMINATION OF CARBON IN BORONCARBIDE C.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ANNEX D. SUGGESTED METHOD FOR THEDETERMINATION OF THE BORON CONTENTOF BORONATED POLYTHENE D.1. . . . . . . . . . . . . . .

ANNEX E. PROCUREMENT CHECK LIST E.1. . . . . . . . . . . . . . .

ALPHABETICAL INDEX


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NES 124Part 4


1.1

1. MATERIALS

1.1 Chemical Composition

a. On analysis the material is to have the following chemical composition:

Element

TypeA

TypeB

ElementParts byweight

Polythene 100 100

NN!−di−2−naphthyl−p−phenylene−diamine (melting range228−235° C)

ordi 2−hydroxy−5−methyl−3−(1−methyl cyclohexyl)−phenylmethane

orTopanol CA 1,1,3−tri (5−tert butly−4−hydroxy−2−methylphenyl) butane

0.1 0.1

Boron carbide − 1.4

b. No other additions will be permitted.

1.2 Quality of Materials

1.2.1 Polythene

a. The polythene is to have a melt flow index from 1.7 to 2.3 when measured byMethod 105C of BS 2782 Part 1. The ash content determined by ignition at750° C to constant weight is to be not more than 0.1%, and the density ofcompression moulded material when determined by Method 509A of BS 2782Part 5 is to be between 0.915 and 0.925g/cm3 at 20° C. No scrap or reclaimedpolythene is to be used.

1.2.2 Boron Carbide

a. The boron carbide is to be in the form of powder, nominally of 280 grit size andsuch that not more than 5% is to be retained on 200 BS mesh. It is to containbetween 77% and 79% of boron and between 19% and 22% of carbon, see AnnexC. The maximum amount of impurities permissible are to be as follows:

ImpuritiesNot more than

ImpuritiesPer cent

CalciumIronSiliconCopperAluminiumCobaltSodiumAll others except Oxygen

1.00.40.40.40.10.10.102


1.2

NES 124Part 4


2.1

2. MANUFACTURE

2.1 Method

a. The base material for both Type A and B sheeting are to be evenly mixed bymilling or by other suitable process and converted into a form suitable forsubsequent operations.

b. The sheets are to be prepared by compression moulding.

2.2 Dimensions and Dimensional Tolerances

a. The sheets are to be supplied in the normal size and thickness stated in theContract Documents. The dimensional tolerances specified in BS 3012 are toapply.

2.3 Freedom from Defects

a. All sheets are to be solid, homogeneous and free from moisture or foreignmaterials. The surfaces are to be smooth and free from any cavities orobtrusions, and are to be planar to within 0.8mm over any circle of 460mmdiameter on that surface.


2.2

NES 124Part 4


3.1

3. TESTS

3.1 Visual and X-Ray Fluoroscopy Examination

a. Sheets less than 6mmthickness are to be visually examined by transmitted lightto ensure freedom from cavities of 5mm diameter and above. Repair by fusedplugs will be permitted subject to a limit of not more than one repair per 0.4m2of area.

b. Sheets 6mm thickness and above are to be examined by X-ray fluoroscopy toensure freedom from cavities of 5mm diameter and above. Repair by press fitor fused plugs will be generally permissible subject to a limit of not more thanone repair per 0.4m2 of area. When press fit plugs are used their positions areto be clearly marked on each side of the sheet prior to despatch. All processesusing ionizing radiations are only to be carried out under protected conditionsin accordance with statutory requirements.

3.2 Density

a. When measured by Method 509A of BS 2782 Part 5 the density of the finishedsheets are to be:

(1) Type A—0.910 to 0.925g/cm3

(2) Type B—0.925 to 0.940g/cm3

3.3 Hydrogen Density

a. The hydrogen density of the finished sheets is to be:

(1) Type A—Not less than 0.128g/cm3

(2) Type B—Not less than 0.125g/cm3

b. The hydrogen density is to be determined by multiplying the density asdetermined inClause 3.1a. by the total hydrogen content of a sample of the samesheet expressed in grammes per gramme of material, which may be determinedby any suitable analytical method and measured to the nearest 0.1%.

3.4 Boron Content of Type B Sheeting Only

a. When determined by a suitablemethod, see AnnexD., the boron content ofTypeB sheeting is to be 1% plus 0.2% minus 0.1%.

3.5 Antioxidant Content

a. When determined by Method 405B of BS 2782 Part 4, the concentration ofNN!−di−2−naphthyl−p−phenylene−diamine in both types of sheeting is tobe not more than 0.15%.

b. Where compositions have been used which contain Nonox WSP, di[(2−dyroxy−5−methyl−3−(1−methyl cyclohexyl)−phenyl)] methane, orTopanol CA, [(1,1,3−tri−(5−tert butyl−4−hydroxy−2−methyl phenyl)butane)], then Method 434A of BS 2782 is to first be employed to identify theantioxidant present. Method 434D of BS 2782 is then to be used to determinethe amount of antioxidant present when the concentration is to be not morethan 0.15% in either type of sheeting.

3.6 Re-tests

a. Should the first test analysis fail to meet the specified chemical composition,two further analyses may be taken if the manufacturer so desires. Should anyof these fail, the material represented by the test specimens is to be rejected.


3.2

NES 124Part 4


4.1

4. IDENTIFICATION AND PACKAGING

a. All sheeting is to be marked for identification in accordance with NES 724 andis to be supplied suitably packaged to prevent any damage to the edges andsurfaces of the sheets.


4.2

NES 124Part 4


A.1 ANNEX A.

ANNEX A.

RELATED DOCUMENTS

A.1 Reference is made to:

Referred to inClause

BS 2782 Methods of testing plastics 3.5b.

BS 2782 Part 1 Thermal properties 1.2.1a.

BS 2782 Part 4 Chemical properties 3.4a.

BS 2782 Part 5 Optical and colour properties, weathering 1.2.1a., 3.1a.

BS 3012 Low and intermediate density polythenesheet for general purpose

2.2a.

NES 724 Packaging 4.a.


A.2ANNEX A.

NES 124Part 4


B.1 ANNEX B.

ANNEX B.

DEFINITIONS AND ABBREVIATIONS

B.1 There are no Definitions and Abbreviations for this NES.


B.2ANNEX B.

NES 124Part 4


C.1 ANNEX C.

ANNEX C.

SUGGESTED METHOD FOR THE DETERMINATION OF CARBON IN BORONCARBIDE

a. Weigh out accurately 0.1g of boron carbide and mix intimately with 1g of leadoxide Pb304. Add some freshly ignited silica andmix well. Place a layer of freshlyignited silica on the bottom of a procelain boat, add the sample, and cover withthe remainder of the silica. The total amount of silica used is 2g. The carboncontent is determined by conversion to carbon dioxide using a standardcombustion technique. A blank determination using the same quantities of leadoxide and silica must be carried out.


C.2ANNEX C.

NES 124Part 4


D.1 ANNEX D.

ANNEX D.

SUGGESTED METHOD FOR THE DETERMINATION OF THE BORON CONTENT OFBORONATED POLYTHENE

a. Place approximately 0.7g of the boronated polythene accurately weighed (cutinto pea size pieces) into a small platinum crucible. Cover the sample with about1g of sodium carbonate. Ash the material at 400° C and then fuse the ash at900° C for approximately 30 minutes.

b. Place the cool crucible and melt in a beaker containing about 100ml of water.Heat the water to dissolve the melt. Make the solution acid to methyl redindicator, and heat for about 10 minutes. Remove the platinum crucible fromthe solution. Add a few drops of bromine water to oxidize any ferrous iron, andboil off the excess bromine. Add about 2g of powdered barium carbonate andboil the solution for at least 2 minutes. A small amount of barium carbonate isto settle to the bottom of the breaker; otherwise more barium carbonate is tobe added. Allow the solution to digest on a warm hotplate until most of thebarium carbonate (plus hydrous oxides of metallic impurities) has settled.

c. Suction-filter the warm solution through a Gooch crucible containing a mat ofasbestos or filter-paper pulp.Wash the residue withwater. Transfer the solutionto a wide-mouth 500ml Erlenmeyer flask. Neutralize the solution withconcentrated HCl as indicated by the yellow to red change of methyl redindicator. Acidify the solution with two or three drops of concentrated HCl.

d. Allow the solution to simmer on a hotplate for about 15 minutes. The solutionis to be distinctly acid at this point to eliminate carbon dioxide. Cool thesolution.

e. Exactly neutralize the excess HCl with 0.1N sodium hydroxide as shown by theindicator change from red to yellow. Add about 4g of mannitol, causing thesolution to turn red. (Boric acid is complexed withmannitol causing it to behavelike a strong acid.) Add two drops of phenolphthalein indicator, and titrate thesolution to the first permanent pink colour with 0.100N NaOH. (The indicatorchange is from red to yellow to pink.) The millilitre of the titrant used after theaddition of the mannitol is equivalent to the boric acid present.

Calculations : % B = (m.l.NaOH) (NaOH) (0.01082) 100)Weight of sample in g


D.2ANNEX D.

NES 124Part 4


E.1 ANNEX E.

ANNEX E.

PROCUREMENT CHECK LIST

TITLE.....................................

REFERENCE.........................

Notes:1. This Check List is to ensure that certain aspects of this Naval Engineering

Standard are consulted when preparing a Statement of TechnicalRequirements for a particular application.

2. Clauses where a preference for an option is to be used or where specific data is to2. Clauses where a preference for an option is to be used or where specific data is tobe added are included in the Check List.

3. Each item is to be marked either

" = included

NA = not applicable

CHECKNo CHECK CLAUSE No " or NA

1 The sheets are to be supplied in the nominal sizeand thickness stated

2.2a.


E.2ANNEX E.

NES 124Part 4


INDEXINDEX.1

ALPHABETICAL INDEX

AAntioxidant, 3.1

BBoron carbide, 1.1

Boron content, 3.1

CChemical composition, 1.1

DDefects, freedom from, 2.1

Density, 3.1

Dimensions, 2.1

IIdentification, 4.1

MMarking, 4.1

Method, 2.1

PPackaging, 4.1

Polythene, 1.1

QQuality of materials, 1.1

RRe-tests, 3.1

TTolerances, 2.1


INDEX INDEX.2

VVisual examination, 3.1

XX-ray fluoroscopy, 3.1

Inside Rear Cover

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Revision of Defence Standards

Defence Standards are revised as necessary by up issue or amendment. It is important thatusers of Defence Standards should ascertain that they are in possession of the latest issue oramendment. Information on all Defence Standards is contained in Def Stan 00-00 Standardsfor Defence Part 3 , Index of Standards for Defence Procurement Section 4 ‘Index of DefenceStandards and Defence Specifications’ published annually and supplemented regularly byStandards in Defence News (SID News). Any person who, when making use of a DefenceStandard encounters an inaccuracy or ambiguity is requested to notify the Directorate ofStandardization (DStan) without delay in order that the matter may be investigated andappropriate action taken.