Regulatory Guide 3.4

Nuclear Criticality Safety in Operations with Fissionable Materials at Fuels and Materials Facilities

ML12220A058
Person / Time
Issue date:	03/20/1986
From:	Minogue R Office of Nuclear Regulatory Research
To:
References
CE 404-4 RG-3.004, Rev. 2
Download: ML12220A058 (5)

0wPM UNITED STATES

NUCLEAR REGULATORY COMMISSION

0 WASHINGTON, D.C. 20555 March 20, 1986 REGULATORY GUIDE DISTRIBUTION LIST (DIVISION 3)

SUBJECT: ISSUANCE OF REVISION 2 TO REGULATORY GUIDE 3.4 AND

WITHDRAWAL OF REGULATORY GUIDE 3.41 With the issuance of Revision 2 to Regulatory Guide 3.4, "Nuclear Criticality Safety in Operations with Fissionable Materials at Fuels and Materials Facilities," the NRC staff is withdrawing Regulatory Guide 3.41,

"Validation of Calculational Methods for Nuclear Criticality Safety."

Revision 2 to Regulatory Guide 3.4 endorses ANSI/ANS-8.1-1983, "Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactors," which is a consolidation of ANSI N16.1-1975/ANS-8.1 (endorsed by Revision 1 of Regulatory Guide 3.4) and ANSI N16.9-1975/ANS-8.11 (endorsed by Regulatory Guide 3.41). Regulatory Guide 3.41 is therefore obsolete. However, withdrawal of Regulatory Guide 3.41 is in no way intended to alter any prior or existing licensing commitments based on its use.

Regulatory guides may be withdrawn when they are superseded by the Commission's regulations, when equivalent recommendations have been incorporated in applicable approved codes and standards, or when changes in methods and techniques or in the need for specific guidance have made them obsolete.

Robert B. Minogue, Director Office of Nuclear Regulatory Research

Revision 2 *

U.S. NUCLEAR REGULATORY COMMISSION March 1986 REGULATORY GUIDE

OFFICE OF NUCLEAR REGULATORY RESEARCH

REGULATORY GUIDE 3A

(Task CE 404-4)

NUCLEAR CRITICALITY SAFETY IN OPERATIONS WITH FISSIONABLE

MATERIALS AT FUELS AND MATERIALS FACILITIES

A. INTRODUCTION

reactors. The standard presents generalized basic criteria and specific limits (maximum subcritical) for some single

233 2 35 2 39 Section 70.22, "Contents of Applications," of 10 CFR units of simple shape containing U, U, pu, Part 70, "Domestic Licensing of Special Nuclear Material," but not for multi-unit arrays. Further, the subcritical limits requires that applications for a specific license to own, specified in the standard allow for uncertainties in the acquire, deliver, receive, possess, use, or initially transfer calculations and experimental data used in their derivation special nuclear material contain proposed procedures to but not for contingencies such as double batching or failure avoid accidental criticality. This guide describes procedures of analytical techniques to yield accurate values.

acceptable to the NRC staff for preventing accidental criticality in operations with fissionable materials at fuels This standard also delineates requirements for estab- and materials facilities (i.e., fuel cycle facilities other lishing the validity and area of applicability of a calcula- than nuclear reactors) and for validating calculational tional method used in assessing nuclear criticality safety.

methods used in assessing nuclear criticality safety. However, it is concerned only with validating calculational methods and does not address important related questions Any information collection activities mentioned in this such as the margin of safety to be used with the method or regulatory guide are contained as requirements in 10 CFR the qualifications of the personnel responsible for the data Part 70, which provides the regulatory basis for this guide. input.

The information collection requirements in 10 CFR Part 70

have been cleared under OMB Clearance No. 3150-0009. This standard does not apply to the assembly of fission- able materials under controlled conditions, e.g., in critical

B. DISCUSSION

experiments. Nor does the standard include the details of administrative controls, the design of processes or equip- ANSI/ANS-8.1-1983, "Nuclear Criticality Safety in ment, the description of instrumentation for process Operations with Fissionable Materials Outside Reactors,"** control, or detailed criteria to be met in transporting was prepared by Subcommittee 8, Fissionable Materials multi-unit arrays of fissionable materials.

Outside Reactors, of the Standards Committee of the American Nuclear Society as a consolidation of revisions to

C. REGULATORY POSITION

ANSI N16.1-1975/ANS-8.1 and ANSI N16.9-1975/ANS-8.11.

ANSI/ANS-8.1-1983 was approved by the American The nuclear criticality safety practices, the single- National Standards Committee N16, Nuclear Criticality parameter limits for fissionable nuclides, and the guidance Safety,. in 1982 and by the American National Standards for multiparameter control contained in ANSI/ANS-8.1-1983 Institute (ANSI) on October 7, 1983. provide procedures acceptable to the NRC staff for pre-I

venting accidental conditions of criticality in handling, ANSI/ANS-8.1-1983 applies to handling, storing, proc- storing, processing, and transporting special nuclear essing, and transporting fissionable material outside nuclear materials at fuels and materials facilities. However, use of ANSI/ANS-8.1-1983 is not a substitute for detailed nuclear criticality safety analyses for specific operations.

• Lines indicate substantive changes from Revision 1.

• • Copies may be obtained from the American Nuclear Society, The guidelines for validating calculational methods for

555 North Kensington Avenue, La Grange Park, Illinois 60525. nuclear criticality safety contained in ANSI/ANS-8.1-1983 USNRC REGULATORY GUIDES The guides are Issued in the following ten broad divisions:

Regulatory Guides are issued to describe and make available to the public methods acceptable to the NRC staff of implementing 1. Power Reactors 6. Products specific parts of the Commission's regulations, to delineate tech- 2. Research and Test Reactors 7. Transportation niques used by the staff in evaluating specific problems or postu- 3. Fuels and Materials Facilities 8. Occupational Health lated accidents, or to provide guidance to applicants. Regulatory 4. Environmental and Siting 9. Antitrust and Financial Review Guides are not substitutes for regulations, and compliance with 5. Materials and Plant Protection 10. General them is not required. Methods and solutions different from those set out In the guides will be acceptable if they provide a basis for the findings requisite to the Issuance or continuance of a permit or Copies of issued guides may be purchased from the Government license by the Commission. Printing Office at the current GPO price. Information on current GPO prices may be obtained by contacting the Superintendent of This guide was Issued after consideration of comments received from Documents, U.S. Government Printing Office, Post Office Box the public. Comments and suggestions for improvements in these 37082, Washington, DC 20013-7082, telephone (202)275-2060 or guides are encouraged at all times, and guides will be revised, as (202)275-2171.

appropriate, to accommodate comments and to reflect new informa- tion or experience.

Issued guides may also be purchased from the National Technical Written comments may be submitted to the Rules and Procedures Information Service on a standing order basis. Details on this Branch, DRR, ADM, U.S. Nuclear Regulatory Commission, service may be obtained by writing NTIS, 5285 Port Royal Road, Washington, DC 20555. Springfield, VA 22161.

provide a procedure acceptable to the NRC staff for

D. IMPLEMENTATION

establishing the validity and area of applicability of cal- culational methods used in assessing nuclear criticality The purpose of this section is to provide information to safety. However, it will not be sufficient merely to refer applicants and licensees regarding the NRC staff's plans for to this guide in describing the validation of a method. using this regulatory guide.

The details of validation indicated in Section 4.3.6 of the standard should be provided to demonstrate the The methods described in this guide were applied to a adequacy of the safety margins relative to the bias and number of specific cases during reviews and selected li- criticality parameters and to demonstrate that the cal- censing actions. These methods reflect the latest general culations embrace the range of variables to which the NRC approach to criticality safety in operations with method will be applied. fissionable materials at fuels and materials facilities. There- fore, except in those cases in which the applicant proposes an acceptable alternative method for complying with Section 7 of ANSI/ANS-8.1-1983 lists additional docu- specified portions of the Commission's regulations, the ments referred to in the standard. Endorsement of methods described in this guide will be used in the evaluation ANSI/ANS-8.1-1983 by this regulatory guide does not of submittals in connection with license applications constitute an endorsement of these documents. submitted under 10 CFR Part 70.

3.4-2

VALUE/IMPACT STATEMENT

The NRC staff performed a value/impact assessment to of this assessment were included in a proposed Revision 2 determine the proper procedural approach for updating to Regulatory Guide 3.4 that was issued for public comment Revision 1 of Regulatory Guide 3.4, "Nuclear Criticality in April 1985. No comments have been received from the Safety in Operations with Fissionable Materials Outside public, and additional NRC staff review has shown that, Reactors," issued in February 1978, which endorsed except for minor clarifications, there was no need to change ANSI N16.1-1975/ANS-8.1. The NRC staff has been in- the regulatory position of the proposed Revision 2 to Regu- volved in the development, review, and approval of a revision latory Guide 3.4. Therefore, the value/impact statement to ANSI N16.1-1975/ANS-8.1 (designated ANSI/ published with the proposed revision is applicable. A copy ANS-8.1-1983), which was approved by the American of the draft regulatory guide and the associated value/impact National Standards Institute on October 7, 1983. The statement (identified by its task number, CE 404-4) is assessment resulted in a decision to develop a revision to available for inspection or copying for a fee at the Com- Regulatory Guide 3.4 that would endorse, with possible mission's Public Document Room at 1717 H Street NW.,

supplemental provisions, ANSI/ ANS-8.1-1983. The results Washington, DC.

3.4-3

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