Regulatory Guide 8.12

Criticality Accident Alarm Systems

ML12220A072
Person / Time
Issue date:	10/31/1988
From:	Office of Nuclear Regulatory Research
To:
References
CE 801-5 RG-8.012, Rev. 2
Download: ML12220A072 (3)

Revision 2 PI, REG, o U.S. NUCLEAR REGULATORY

COMMISSION

October 1988 REGULATORY

GUIDE'**e OFFICE OF NUCLEAR REGULATORY

RESEARCH /7 I ! A REGULATORY

GUIDE 8.12 (Task CE 801-5)CRITICALITY

ACCIDENT ALARM SYSTEMS

A. INTRODUCTION

Section 70.24, "Criticality Accident Requirements," of 10 CFR Part 70, "Domestic Licensing of Special Nuclear Material," requires licensees who are authorized to possess special nuclear material in excess of certain amounts to maintain a criticality accident alarm system. This guide describes a system acceptable to the NRC staff for meeting the Commission's requirements for a criticality accident alarm system.Any information collection activities mentioned in this regulatory guide are contained as requirements in 10 CFR Part 70, which provides the regulatory basis for this guide.The information collection requirements in 10 CFR Part 70 have been cleared under OMB Clearance No. 3150-0009.

B. DISCUSSION

Section 70.24 requires, in part, a monitoring system capable of detecting a criticality that produces an absorbed dose in soft tissue of 20 rads of combined neutron and gamma radiation at an unshielded distance of 2 meters from the reacting material within 1 minute. Criticality accident alarm systems are also discussed in American National Standard ANSI/ANS-8.3-1986, "Criticality Accident Alarm System," 1 which has the same detection criterion.

C. REGULATORY

POSITION The guidance on criticality accident alarm systems contained in ANSI/ANS-8.3-1986, "Criticality Accident lCopies may be obtained from the American Nuclear Soci-ety, 555 North Kensington Avenue, La Grange Park, Illinois 60525.Alarm System," is generally acceptable to subject to the following limitations:

1. Section 70.24 of 10 CFR Part 70 requires alarm coverage "in each area in which such licensed special nuclear material is handled, used, or stored ... ," whereas paragraph

4.2.1 of the standard states that the need for criticality alarms must be evaluated for such areas. If such an evaluation does not determine that a potential for criticality exists, as for example where the quantities or form of special nuclear material make criticality practically impossible or where geometric spacing is used to preclude criticality, such as in some storage spaces for unirradiated nuclear power plant fuel, it is appropriate to request an exemption from § 70.24.

2. Paragraph

70.24(a)(1)

of 10 CFR Part 70 requires that each area be covered by two detectors, whereas para-graph 4.5.1 of the standard permits coverage by a reliable single detector.

D. IMPLEMENTATION

The purpose of this section is to provide information to applicants regarding the NRC staff's plans for using this regulatory guide.Except in those cases in which an applicant proposes an acceptable alternative method for complying with § 70.24 of 10 CFR Part 70, the method described in this guide will be used in the evaluation of designs of criticality accident alarm system

s. 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 nlques 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.

VALUE/IMPACT

STATEMENT A draft value/impact statement was published with the proposed Revision 2 to Regulatory Guide 8.12 (Task CE 801-5) when the draft guide was published for public comment in May 1988. No changes were necessary, so a separate value/impact statement for the final guide has not been prepared.

A copy of the draft value/impact statement is available for inspection and copying for a fee at the Commission's Public Document Room at 2120 L Street NW., Washington, DC, under Task ('CF 801-5.8.12-2 UNITED STATES NUCLEAR REGULATORY

COMMISSION

WASHINGTON.

D.C. 20555 OFFICIAL BUSINESS PENALTY FOR PRIVATE USE, $300 FIRST CLASS MAIL POSTAGE b FEES PAID USNRC PERMIT No. G-67