ML20004E864
| ML20004E864 | |
| Person / Time | |
|---|---|
| Site: | 07000687 |
| Issue date: | 01/31/1981 |
| From: | NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | |
| Shared Package | |
| ML20004E862 | List: |
| References | |
| TASK-OH-015-4, TASK-OH-15-4, TASK-OS REGGD-08.012, REGGD-8.012, NUDOCS 8106150540 | |
| Download: ML20004E864 (2) | |
Text
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(@% U.S. NUCLEAR REG GUIDE
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OFRCE OF STANDARDS DEVELOPMENT REGUI.ATORY GUIDE 8.12 1
(Task OH 0154)
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CRITICALITY ACCIDENT ALARM SYSTEMS A. INTRODUCTION in excess of certain amounts. Thus, Regulatory Position I discusses certain situations where an exemption from the Section 70.24, "Crincality Accident Requirements," of '
cnticality accident alarm system is appropnate.
10 CFR Part 70," Domestic Licensing of Special Nuclear Mate-nal," requires licensees who are authorized to possess special C. REGul ATORY POSITION nuclear matenal in excess of certain amounts to maintain a criticality accident alarm system. This guide describes a sys-T.te guidance on criticality accident alarm systems tem acceptable to the NRC staff for meeting the Commis-cor.tained in ANSI /ANS 8.3-1979, " Criticality Accident sion's requirements for a criticality accident alarm system.
Alarm System," is generally acceptable to the NRC staff, subject to the following:
B. DISCUSSION
- 1. Secnon 70.24 of 10CFR Part 70 requires alarm cover-Section 70.24 requires, in part, the detection of a age "in each area in which such licensed special nuclear mate-cnncality that produces an absorted dose in soft tissue of nal is handled, used, or stored..." whereas paragraph 4.2.1 20 rads of combined neutron and gamma radiation at an of the standard states that the need for enticality alarms unsfuelded distance of 2 meters from the reactmg matenal shall be evaluated for such areas. If such an evaluation does within 1 minute. This sensitivity should be enough to not determine that a potential for criticality exists, as for detect any accidental enticality. Cnticality accident alarrn example where the quantities or form of special nuclear p
systems are also discussed in American National Standard _ _ matenal make criticality practically impossible or where
.:-t ANSI /ANS 8.3-1979,I *Cnncality Ace 2 dent Alarm System,"
geometric spacing is used to preclude criticality, such asin t
wh2ch has the same detection criterion.
some storage spaces for unitraaiated nuclear pcwer plant fuel, it is appropriate to request an exemption] from @ 70.24.
Paragraph 4.1 of ANSI /ANS 8.3-1979 requires c-iticality accident alarms "wherever it is deemed that they will result
- 2. Paragraph 7C.24(a)(1) of 10 CFR Part 70 requires that in a reduction in total nsk." The use of criticality alar-ns is each area be covered by two detectors, tn contrast to para-not intended to prod $2ce a hazard for workers, but to graph 4.5.1 of the standard, which allows coverage by a reduce any hazard that may exist from work:ng with single detector.
materials that have a potential for enticality. Some situations exist in which the workplace could be evacuated as a result
- 3. The signal for evacuation should be sounded auto-of a false alarm and a hazard could be posed by the evacuation.
matically upon detection of an accident.
Such situations should be avoided. For example, where the quanuties or form of special nuclear material make enticality
- 4. A quick screening capability as required in paragraph pracucally impossible or where geometnc spacing is used to 70.Mb) of 10CFR Part Al may be previded instead of the preclude enneality, such as in some storage spaces for more extensive dosimetry requirements statedin paragraph 6.6 unirradiated nuclear power plant fuel, alarms are not of the standard.
needed. However, s 70.24 requires alarms whenever i
licensees are authorized to possess special nuclear matenal D. IMPt.EMENTATION N sutstanual numeer or chanses in this rewwon has maae is The purpose of this section is to provide information to impractical to endscate the changes with lines in the margin.
applicants and licensees regarding the NRC staff's plans for using this regulatory guide. Except in those cases in which I Copies mov de octaned from the Arnergan 'Wuclear Society, 5 s 5 North Kansan gton Avenue. La Grange Park. nhnois 6os2s.
an applicant or licensee proposes an acceptable alternanve USNRC REGULATORY GutOEs Comments snouse be sent to tne Secretary of tne comeness.on, U.S.
Nuclear segusatory Commesseon, wannington. Q.C. 20sss, Regulatory Gueces are issued to sescrise and ename avaelao6e to the Attentsont oocheting ano servece Grancn.
ou ceic met noes acceptanee to tne N R c st aff of em osomen t6aq requistions. to oeeineate tec%
The gusoes are issued in the fonowmg ten promo alwessons:
commess on's nq soecific proosems or costu-specific cares of tne nioves useo ov ene staff en eva4uat tateo accioents or to orowice gu.cance to acolicants. Requiatory
- t. power Reactors S. Products Guaces are not suostitutes for requist ons. ano comosiance wit m
- 2. mesearen ano Test Reactors
- 7. Transoortation enem es not reovereo. uetnoes sno soiutions sifferont from enose set
- 3. Nees and watereals Facisitees
- 4. occupationai wealtn out an tne gusoes en se accentaone if tney crowice a cases 'or tne 4 Environmentas an s s.teng
- 9. Antitrust ano Financima Rev.ews finoangs reou ute to tne issuance or continuance of a permet or
- s. uatoriass and plant Protection 10. Generne lacease av tne Commessson.
Coo.es of issueo gueoes may no ourenated at tne current Government ruture gueces sn see.
comments ano su90estions for amorovements in tnese guides are orent6rq Cff 6ce prece. A sunscripteon service for encouragea at all times, ano queces eit oe revised, as acoroor* ate, cafic covessons es awassapee tnrougn tne Governenent orenting office, to accommodate comanents and to reflect new inf orm a tion or
- nformation on tne suoscreation serwece and current GPO oreces may i
esoereence. nes guioe was reviseo as a result of suottantive com-se ootained oy writsag tne U.S. Nudear R egulatory Commiss.on, j
monts receewoo from tne puosec ano accationes statt toweew.
w asn ia gt on, O.C. 20sss. Attention: ouosicataons saaes Manager.
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810 615 0 eg
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- method, the staff will use the methods described hersin If.an applicant or !! censes wishes to use the method after March 1. !981, in evaluating designs of enticality described in this'resulatory guide before March 1,1981 the accident alarm systems to meet the requirements of l 70.24 applicarit's, alarm system design or the licensee's alerm of the C:mmission's regulations.
system w111 be evaluated on the basis of this gulds.
A VALUE/lMPACT STATEMENT' This revision to Regulatory Guide 8.12. " Criticality As indicated in Regulatory Position 1, a request for an Accidmt Alarm Systema,"clanfica,in Regulatory Position 1, exemption to the requi: aments of l 70.24, "Cnticality where criticality accident alarm rystems are not appropdate Accident Requirements," of 10 CFR Part 70, " Domestic and adds the position that in situations where alarm systems Licensing of Special Nuclear Matenal,"is appropnate when have be3n instaDed, the alarm should automaticany sound there is no real possibility of a enticality, for example in when criticality is reached. These positions have been situations where geometne spacing is used to preclude reach 1d as a result of staff review of the draft guide and criticality, such as in storage spaces for unirradiated nuclear evaluatirn of public comments on it.
Power plant fuel..
" Draft Guide OH on s.4 aneits nasoetated value/ impact statement This revision to the guide describes a enticality accident N.kic'# de'u$ 5cEmin'i EN."IItEs7
- 57 dea'n n'sYU.
alarm system acceptabic to the NRC staff for meeting the P
o.:.
Commission's regulations for such a system.
I I
P00R ORIGINAL
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8.12 2
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