ML003739454

Rev 1 Criticality and Other Interior Evacuation Signals

ML003739454
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Issue date:	03/31/1981
From:	Office of Nuclear Regulatory Research
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RG-8.5, Rev 1
Download: ML003739454 (2)

Text

Revision I

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E*0*'March 1981 0,tof U.S. NUCLEAR REGULATORY COMMISSION REGULATORY GUIDE OFFICE OF STANDARDS DEVELOPMENT REGULATORY GUIDE 8.5 CRITICALITY AND OTHER INTERIOR EVACUATION SIGNALS A. INTRODUCTION Section 70.24, "Criticality Accident Requirements," of 10 CFR Part 70, "Domestic Licensing of Special Nuclear Material." requires criticality detection and alarm systems in any area containing special nuclear material when the licensee is authorized to possess such special nuclear mate rial in excess of certain specified amounts. This guide defines the characteristics of an audible signal acceptable to the NRC staff for use where prompt, complete evacuation is required to prevent serious injury from radiation exposure.

B. DISCUSSION ANSI/ANS N2.3-1979,1 "Immediate Evacuation Signal for Use in Industrial Installations," which is a revision of USASI N2.3-1967, was approved by the American National Standards Institute (ANSI) on September 13, 1979. The standard defines the characteristics of an immediate evacua tion signal system.

Whereas USASI N2.3-1 967 specified the characteristics of a unique audible signal for evacuation of the area potentially affected by the consequences of a nuclear criticality acci dent. ANSI/ANS N 2.3-1979 presents the recognized desirable characteristics of signal systems and good practices in their The substantial number of changes in this revision has made it impractical to indicate them with lines in the margin.

ICopies may be obtained from the American Nuclear Society.

5SS North Kensington Avenue, LaGrange Park, Illinois 60525.

USNRC REGULATORY GUIDES Regulatory Guides are issued to describe and make available to the public methods acceptable to the NRC staff of implementing specific parts of the Commission's regulations, to delineate tech niques used by the staff in evaluating specific problems or postu lated accidents, or to provide guidance to applicants. Regulatory Guides are not substitutes for regulations, and cor-pliance with 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 license by the Commission.

Comments and suggestions for improvements in these guides are encouraged at all times, and guides will be revised, as approp:iate, to accommodate comments and to reflect new information or experience. This guide was revised as a result of substantive com ments received from the public and additional staff review.

conception, installation, and operation. A description of typical characteristics for an evacuation signal and the signal generator that were included as requirements in the body of USASI N2.3-1967 have been placed in Appendix B to ANSI/ANS N2.3-1979 simply asan example of compliance with the standard.

C. REGULATORY POSITION The characteristics of an immediate evacuation signal described in ANSI/ANS N2.3-1979, "Immediate Evacua tion Signal for Use in Industrial Installations," are gen erally acceptable to the NRC staff for use wherever such a system may be needed or required except that the mini mum duration of the signal should be sufficient to ensure evacuation and permit implementation of access control.

D. IMPLEMENTATION The purpose of this section is to provide information to applicants and licensees regarding the NRC staff's plan for using this regulatory guide. This guide reflects practices currently acceptable to the NRC staff. Except in those cases in which the applicant or licensee proposes accept able alternative practices or methods for complying with specified portions of the Commission's regulations, the practices or methods described herein will be used as a basis for evaluating applications for licenses to possess special nuclear material in quantities subject to §70.24 of 10 CFR Part 70.

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