ML20238E775

Reg Guide 03.071 (Draft Was Issued as DG-3013), Nuclear Criticality Safety Stds for Fuels & Matl Facilities

ML20238E775
Person / Time
Issue date:	08/31/1998
From:	NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:
References
TASK-*****, TASK-RE REGGD-03.071, REGGD-3.071, NUDOCS 9809020181
Download: ML20238E775 (7)

Text

co U.S. NUCLEAR REGULATORY COMMISSION August 1998 O

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U g***** )OFFICE OF NUCLEAR R DE REGULATORY GUIDE 3.71 (Draft was issued as DG-3013)

NUCLEAR CRITICALITY SAFETY STANDARDS FOR FUELS AND MATERIAL FACILITIES A. INTRODUCTION The information collections contained in this regu-latory guide are covered by the requirements of 10 CFR In 10 CFR Part 70," Domestic Licensing of Special Part 70, which were approved by 'he Office of Manage-Nuclear Material," Section 70.20," General License To ment and Budget, approval number 3150-0009,and Own Special Nuclear Material," defines a specific li-10 CFR Part 76.The NRC may not conduct or sponsor, cense to acquire, delive r, receive, possess, use, transfer, and a person is not required to respond to, a collection import,or export special nuclear material. According to ofinformation unless it displays a currently valid OM B

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10 CFR 70.22, " Contents of Applications," each ap-control number, j

plication for such a license must contain proposed pro-cedures to avoid nuclear criticality accidents. in 10 B. DISCUSSION CFR Part 76, " Certification of Gaseous Diffusion

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O Plants," Section 76.87, " Technical Safety Require-The American Nuclear Society's Standards Sub-i

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ments," states that the technical safety requirements committee 8," Operations with Fissionable Materials should reference procedures and equipment applicable Outside Reactors" (ANS-8), has developed national to criticality prevention.

standards for the prevention and mitigation of critical-ity accidents during handling, processing, storing, and

,This regulatory guide has been developed to pro-transporting special nuclear materials at fuels and ma-vide guidance on complying with these portions of the terial facilities. These national standards have been ap-NRC's regulations by describing procedures for pre-proved by the American Nuclear Society Committee I

venting nuclear criticality accidents in operations in-N16 on Nuclear Criticality Safety and by the American I

tolving handling, processing, storing, and transporting National Standards Institute (ANSI). The ANSI /

special nuclear matenal at fuels and material facilities.

ANS-8 nuclear criticality safety standards provide This regulatory guide endorses specific ANSI /ANS-8 guidance and criteria on good practices for nuclear criti-nuclear criticality safety standards for these purposes, cality safety at fuels and material facilities.

This guide also consolidates and replaces the guidance

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from a number of regulatory guides, thereby withdraw-The ANSI /ANS-8 national standards list additional h ing those regulatory guides. This guide is not intended documents as references. The specific applicability or to be used by nuclear reactor licensees.

acceptability of these listed documents will be covere

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LBRC RLGl'lAlORY Gl1DL 5 The gwdes me tasued in the followng ten broad divisions Regulatory Guirtes are issued to describe and make avalable to the pubhc such tnforma tion as methods acceptable to the NRC staff for implementing speahc parts of the Com-1 Power Reactors 6 Products i

mission s regulations. tectvwques used by the staff in evaluating speafic problems or pos' 2 Research and Test Reactors 7 Transportatm tulated accidents, and data needed by the NRC staff in its review of applicates for per.

3 Fuels and Materials f acht ee 8 Occupational Health Q

mits and hconses Regulatory guides are not substitutes for regulates and comphance 4 Environmental and Siting 9 Antitrust and Finanaal Review l

wth them o not requwed Methods and solutions d;fferent from those sel out m the guides 5 Matemals and Plant protection to General wil be acceptable if they proede a basis for the findings requisite to the issuance or con-tinuance of a permet or bcense by the Commission

/"N This guide was issued after considerate of comments received from the pubhc Com-duction and Distneution Services Secta O'hce of the Cheef Informate Othcar U S No.

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j guides wil be revised as appropnate, to accommodate comments and to reflect new in.

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rnents and suggestions for improvements in these Quedes are encouraged at sil times and clear Regulatory Commission. Wasnengton DC 20555-0001, or by tan at (309415-5272 lasued guides may also be purchased from the Nutsal Technical information Serwce on Wotten Comments may be submitted to the Rules Recew and Dweetives Branch DFIPS, a standing order basis Detsis on this service may be obtened by wnting NTIS 5285 Pod ADM U S Nuclear Regulatory Commission, Washington. DC 20555-0001 Royal Road. Spnngheid VA 22161 1..

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separately in other regulatory guides, where ANSI /ANS-8.21-1995,"Use of Fixed Neutron Ab-appropriate, sorbers in Nuclear Facilities Outside Reactors" C. REGULATORY POSITION ANSI /ANS-8.22-1997, " Nuclear Criticality Safety Based on Limiting and Controlling Moderators" The following ANSI /ANS-8 nuclear en.ticah.ty safety standard documents describe precedures and ANSI /ANS-8.23-1997," Nuclear Criticality Accident recommendations that should be followed to prevent Emergency Planning and Response" l

and mitigate nuclear criticality accidents.

metWs desc@ed b h MAM4 nu-ANSI /ANS-8.1-1983(Reaffirmed in 1988)," Nuclear clear criticality safety standards have been applied m. a Criticality Safety in Operations with Fissionable number of specific cases during reviews and selected Materials Outside Reactors" licensing actions. These methods reflect the latest g:n-ANSI /ANS-8.3-1997, " Criticality Accident Alarm eral NRC approach to nuclear criticality safety in op-System" erations involving handling, processing, storing, and transporting special nuclear material at fuels and mate-ANSI /ANS-8.5-1996, "Use of Borosilicate-Glass rial facilities.

Raschig Rings as a Neutron Absorber in Solutions Most of the ANSI /ANS-8 nuclear criticality safety of Fissile Material" standards have been endorsed by NRC in other regula-tory guides.This regulatory guide consolidates and re-ANSI /ANS-8.6-1983 (Reaffirmed in 1995), " Safety pl ces the following regulatory guides without altering in Conducting Suberitical Neutron-Multiplication any existing licensing commitments nor introduemg Measurements In Situ" any new requirements. These regulatory guides are ANSI /ANS-8.7-1975 (Reaffirmed in 1987), " Guide therefore being withdrawn.

for Nuclear Criticality Safety in the Storage of Fis-Regulatory Guide 3.1,"Use of Borosilicate-Glass Ras-site Materials" chig Rings as a Neutron Absorber in Solutions of ANSI /ANS-8.9-1987(Reaffirmed in 1995)," Nuclear Fissile Material"(Revision 2, September 1987)

Criticality Safety Criteria for Steel-Pipe Intersec-tions Containing Aqueous Solutions of Fissile Ma-Regulatory Guide 3.4,(, Nuclear C,riticality Safety in Operations with Fissionable Matenals at Fuels and tenals,,

Materials Facilities"(Revision 2, March 1986)

ANSI /ANS-8.10-1983(Reaffirmed in 1988),"Crite-Regulatory Guide 3.43," Nuclear Criticality Saf< ty in na for Nuclear Criticality Safety Controls m Op-the Storage of Fissile Materials"(Revision 1, April erations With Shielding and Confinement' 1979)

ANSI /ANS-8.12-1987 (Reaffirmed in 1993), "Nu-Regulatory Guide 3.45 " Nuclear Criticality Safety for clear Criticality Control and Safety of Steel-Pipe Intersections Containing Aqueous

• Plutonium-Uranium Fuel Mixtures Outside Solutions of Fissile Materials" (Revision 1, April Reactors" 19g9)

ANSI /ANS-8.15-1981 (Reaffirmed in 1995), "Nu-Regulatory Guide 3.47, " Nuclear Criticality Control clear Criticality Control of Special Actinide Ele-and Safety of liomogeneous PlutomuneUranium ments" Fuel Mixtures Outside Reactors"(July 1981)

ANSI /ANS-8.17-1984(Reaffirmed in 1997),"Criti-Regulatory Guide 3.57," Administrative Practices for cality Safety Criteria for the llandling, Storage, Nuclear Criticality Safety at Fuels and Materials and Transportation of LWR Fuel Outside Reac-Facilities"(October 1986) tors" Regulatory Guide 3.58, " Criticality Safety for llan-ANSI /ANS-8.19-1996," Administrative Practices for dling, Storing, and Transporting LWR Fuel at Nuclear Critica!ity Safety" Fuels and Materials Facilities"(October 1986)

ANSI /ANS-8.20-1991, " Nuclear Criticality Safety Regulatory Guide 3.68, " Nuclear Criticality Safety Training" Training"(April 1994) 3.71 - 2

l Regulatory Guide 3.70, "Use of Fixed Neutron Ab-The guidance on using shielding and confinement l

sorbers at Fuels and Materials Facilities"(August as a nuclear criticality safety control contained in l Q 1997)

ANSI /ANS-8.10-1983(Reaffirmed in 1988),"Crite-ria for Nuclear Criticality Safety Controls in Opera-Regulatory Guide 8.12 " Criticality Accident Alarm tions with Shielding and Confinement," is generally Systems" (Revision 2, October 1988) accepted by the NRC staff. An exception to Section l

4.2.1 is that the radiation source strengths and releases from a nuclear criticality accident are assumed to be The ANSI /ANS-8 nuclear criticality safety stan-from an excursion occurring in an unfavorable geome-dards listed above provide procedures and methodolo-try containing a solution of 400 g/l of uranium enriched gy generally acceptable to the NRC staff for the preven-in U-235.The excursion produces an initial burst of

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tion and mitigation of nuclear criticality accidents.

1E+18 fissions in 0.5 second followed successively at liowever, use of the ANSI /ANS-8 nuclear criticality 10 minute intervals by 47 bursts of 1.9E+17 fissions for safety standards is not a substitute for detailed nuclear a total of 1E+19 fissions in 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. The excursion is criticality safety analyses for specific operations. Ex-assumed to be terminated by evaporation of 100 liters I

ceptions to some of the ANSI /ANS-8 nuclear critical-of the solution. A less conservative nuclear criticality ity safety standards are as follows.

accident condition may be used if detailed analyses of credible nuclear criticality accidents are performed and The guidelines for validating calculational meth-shown 'o be applicable to the conditions being ods for nuclear criticality safety contained in ANSI /

evaluated.

ANS-8.1-1983(Reaffirmed in 1988)," Nuclear Criti-cality Safety in Operations with Fissionable Materials The general safety criteria and criteria to establish Outside Reactors," provide a procedure acceptable to suberiticality contained in ANSI /ANS-8.17-1997, the NRC staff for establishing the validity and applica.

" Criticality Safety Criteria for the llandling, Storage, bility of calculational methods used in assessing nu.

and Transportation of LWR Fuel Outside Reactors,"

clear criticality safety. llowever,it will not be sufficient provide guidance acceptable to the NRC staff for pre-merely to refer to this guide in describing the validation venting nuclear criticality accidents in handling, stor-O) i of a method. The details of validation stated in Section ing, and transporting fuel assemblies at fuels and mate-4.3.6 of the standard should be provided to demonstrate rial facilities. The only exception is that credit for fuel the adequacy of the margins of subcriticality relative to burnup may be taken only when the amount of burnup the bias and criticality parameters, to demonstrate that is confirmed by physical measurements that are ap-the calculations embrace the range of variables to propriate for each type of fuel assembly in the environ-which the method will be applied, and to demonstrate ment in which it is to be stored.

the trends in the bias upon which extension of the area The NRC staff will follow the requirements as de-of applicability will be based.

noted in the ANSI /ANS-8 national standards. The The guidance on criticality accident alarm systems w rd "shall" in a standard denotes a requirement, the word "should" denotes a recommendation, and the

. contained in ANSI /ANS-8.3-1997," Criticality Acci-word "may" denotes permission, neither a requirement dent Alarm System," is generally acceptable to the nor a recommendation. When an applicant or licensee NRC staff. An exception is that criticality alarm sys-tems are required by 10 CFR 70.24," Criticality Acci-pmmus to the ANSI /ANS-8 national standards cited in this regulatory guide, all operations must be per-dent Requirements,"in each area in which special nu-f rmed in accordance with the requirements stated in

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clear material is handled, used, or stored, while Section the national standards but not necessarily with its rec-4.2.1 of the standard requires an evaluation for such commendations. Recommendations given in the ANSI /

areas. Another exception is that each area is required by ANS-8 national standards may be followed unless an i

10 CFR 70.24 and 10 CFR 76.89," Criticality Accident exception is stated in this regulatory guide or otherwise Requirements," to be covered by two detectors, where-specified in 10 CFR Part 70 or Part 76, or addressed by as Section 4.5.1 of the standard permits coverage by a ther acceptable methods.

single reliable detector. Finally, a monitoring system capable of detecting a nuclear criticality that produces D. IMPLEMENTATION Q

an absorbed dose in soft tissue of 20 rads of combined Q

neutron and gamma radiation at an unshielded distance The purpose of this section is to provide informa-of 2 meters from the reacting material within 1 minute tion to applicants and licensees regarding the NRC is required by 10 CFR 70.24 and 10 CFR 76.89, staff's plans for using this regulatory guide.

3.71 -3 I

Except in those cases in which an applicant or li-the evaluation of submittals in connection with license censee proposes an acceptable alternative method for applications submitted under 10 CFR Part 70," Domes-complying with the specified portions of the NRC's tic licensing of Special Nuclear Material," and 10 CFR regulations, the methods in this guide will be used in Part 76," Certification of Gaseous Diffusion Plants."

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REGULATORY ANALYSIS f-A draft regulatory analysis was published with the draft of this guide when it was published for public comment (Task DG-3013, January l-'

1998). No changes were necessary, so a separate regulatory analysis has not been prepared for Regulatory Guide 3.71. A copy of the draft regulato-ry analysis is available for inspection or copying for a fee in the NRC's Public Document Room at 2120 L Street NW., Washington, DC, under Task DG-3013.

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