1、ANSI/ANS-8.23-2007nuclear criticality accidentemergency planning and responseANSI/ANS-8.23-2007REAFFIRMED May 31, 2012 ANSI/ANS-8.23-2007 (R2012) This standard has been reviewed and reaffirmed with the recognition that it may reference other standards and documents that may have been superseded or w
2、ithdrawn. The requirements of this document will be met by using the version of the standards and documents referenced herein. It is the responsibility of the user to review each of the references and to determine whether the use of the original references or more recent versions is appropriate for
3、the facility. Variations from the standards and documents referenced in this standard should be evaluated and documented. This standard does not necessarily reflect recent industry initiatives for risk informed decision-making or a graded approach to quality assurance. Users should consider the use
4、of these industry initiatives in the application of this standard. ANSI/ANS-8.23-2007American National StandardNuclear Criticality AccidentEmergency Planning and ResponseSecretariatAmerican Nuclear SocietyPrepared by theAmerican Nuclear SocietyStandards CommitteeWorking Group ANS-8.23Published by th
5、eAmerican Nuclear Society555 North Kensington AvenueLa Grange Park, Illinois 60526 USAApproved March 23, 2007by theAmerican National Standards Institute, Inc.AmericanNationalStandardDesignation of this document as an American National Standard attests thatthe principles of openness and due process h
6、ave been followed in the approvalprocedure and that a consensus of those directly and materially affected bythe standard has been achieved.This standard was developed under procedures of the Standards Committee ofthe American Nuclear Society; these procedures are accredited by the Amer-ican National
7、 Standards Institute, Inc., as meeting the criteria for AmericanNational Standards. The consensus committee that approved the standardwas balanced to ensure that competent, concerned, and varied interests havehad an opportunity to participate.An American National Standard is intended to aid industry
8、, consumers, gov-ernmental agencies, and general interest groups. Its use is entirely voluntary.The existence of an American National Standard, in and of itself, does notpreclude anyone from manufacturing, marketing, purchasing, or using prod-ucts, processes, or procedures not conforming to the stan
9、dard.By publication of this standard, the American Nuclear Society does not insureanyone utilizing the standard against liability allegedly arising from or afterits use. The content of this standard reflects acceptable practice at the time ofits approval and publication. Changes, if any, occurring t
10、hrough developmentsin the state of the art, may be considered at the time that the standard issubjected to periodic review. It may be reaffirmed, revised, or withdrawn atany time in accordance with established procedures. Users of this standardare cautioned to determine the validity of copies in the
11、ir possession and toestablish that they are of the latest issue.The American Nuclear Society accepts no responsibility for interpretations ofthis standard made by any individual or by any ad hoc group of individuals.Requests for interpretation should be sent to the Standards Department atSociety Hea
12、dquarters. Action will be taken to provide appropriate response inaccordance with established procedures that ensure consensus on theinterpretation.Comments on this standard are encouraged and should be sent to SocietyHeadquarters.Published byAmerican Nuclear Society555 North Kensington AvenueLa Gra
13、nge Park, Illinois 60526 USACopyright 2007 by American Nuclear Society. All rights reserved.Any part of this standard may be quoted. Credit lines should read “Extracted fromAmerican National Standard ANSI0ANS-8.23-2007 with permission of the publisher,the American Nuclear Society.” Reproduction proh
14、ibited under copyright conventionunless written permission is granted by the American Nuclear Society.Printed in the United States of AmericaForewordThis Foreword is not a part of American National Standard “Nuclear Criticality AccidentEmergency Planning and Response,” ANSI0ANS-8.23-2007.!This stand
15、ard provides criteria for emergency planning and response to a nu-clear criticality accident for facilities outside reactors that process, store, orhandle fissionable material. This standard assumes that an alarm system thatcomplies with American National Standard “Criticality Accident Alarm System,
16、”ANSI0ANS-8.3-1997 R2003!, is in place. This standard focuses on those ele-ments of planning and response needed specifically in the event of a criticalityaccident. It is not a general emergency planning and response standard.This revision adds three appendices. The appendices are intended to assist
17、technical staff in fulfilling some of their responsibilities noted in this standard.Few changes were made to the body of the standard. Section 4.19! was revisedbecause it was noted that a system to read dosimeters is needed to obtain usefulinformation from them. Section 5.1 was revised to emphasize
18、that accidentcharacterization is done to support emergency response planning. Section 7 wasreformatted without sub-subsections because reentry, rescue, and stabilizationare interrelated topics.The working group would like to gratefully acknowledge the contributions byIchiro Nojiri, who died prior to
19、 the publication of this revision.This standard was prepared by Working Group ANS-8.23, composed of the fol-lowing members:J. S. Baker Chair!, Los Alamos National LaboratoryD. E. Cabrilla, U.S. Department of EnergyR. W. Carson, Babcock the word “should” is used to denote arecommendation; and the wor
20、d “may” is usedto denote permission, neither a requirementnor a recommendation.3.3 Glossary of termsdrill: Supervised instruction intended to test,develop, maintain, and practice the skills re-quired in a particular emergency response ac-tivity. A drill may be a component of an exercise.emergency co
21、ordinator: A person autho-rized to direct the overall emergency response.emergency response: Actions taken from thetime of identification of a suspected, imminent,or actual criticality accident to stabilization ofthe event, including the assumption that anaccident has occurred, response to the emer-
22、gency, and actions to begin subsequent recov-ery operations.exercise:An activity that tests one or more por-tions of the integrated capability of emergencyresponse plans, equipment, and organizations.facility: A defined area where fissionable ma-terial is located.immediate evacuation zone: The area
23、sur-rounding a potential criticality accident loca-tion that must be evacuated without hesitationif a criticality accident alarm signal is activated.site: A defined area containing one or morefacilities.technical staff: Personnel with specific skillsand experience who can assist in the implemen-tati
24、on of the requirements defined in this stan-dard. Such personnel may include, but are notlimited to, criticality safety, health and safety,and facility process support personnel.4 Responsibilities4.1 Management responsibilitiesManagement shall ensure the following:1! Staff with relevant expertise is
25、 provided;1!Numbers in brackets refer to corresponding numbers in Sec. 9, “References.”12! An emergency response plan is estab-lished, exercised, and maintained;3! Immediate evacuation zones and evacua-tion routes are established;4! A personnel assembly station or sta-tions! is established, and a me
26、thod is pro-vided for timely accounting of all personnelwho were within the immediate evacuationzone at the time of the evacuation;5! Instrumentation and equipment needed torespond to a criticality accident are provided;6! The level of readiness including train-ing! needed for response to a critical
27、ity acci-dent is adequate;7! The capability to perform radiological doseassessments for response to criticality acci-dents is provided;8! A communication system for central co-ordination of all site emergency activities isprovided;9! A nuclear accident dosimetry system asspecified in American Nation
28、al Standard “Do-simetry for Criticality Accidents,” ANSI N13.3-1969 R1981!withdrawn!3#, is provided;10! Equipment such as a criticality acci-dent alarm system defined in ANSI0ANS-8.3-1997 R2003!1#!and procedures are in placeto activate the emergency response whenneeded.4.2 Technical staff responsibi
29、lities4.2.1 PlanningThe technical staff shall1! identify potential criticality accidentlocations;2! evaluate and characterize potential crit-icality accidents, including radiological doseprediction;3! determine the instrumentation and equip-ment requirements for emergency responseactivities;4! defin
30、e the immediate evacuation zonearound the potential criticality accidentlocations;5! participate in the planning, conduct, andevaluation of exercises and drills.4.2.2 Emergency responseDuring an emergency response the technicalstaff shall1! be available to advise and assist the emer-gency coordinato
31、r in responding to the criti-cality accident;2! conduct a radiological dose assessmentappropriate for a criticality accident.5 Emergency response planning5.1 Evaluation5.1.1Potential criticality accident locations and pre-dicted accident characteristics shall be evalu-ated and documented in sufficie
32、nt detail to assistemergency planning. This evaluation may bebased on professional judgment or a more de-tailed analysis. The description should includethe estimated fission yield. The likelihood ofrecurrence of criticality should be considered.5.1.2An immediate evacuation zone shall be estab-lished
33、 based on the documented evaluation.Emergency response planning shall establish amaximum acceptable value for the absorbeddose at the immediate evacuation zone bound-ary. The basis for the maximum acceptable valueshall be documented. Shielding may be consid-ered in establishing the immediate evacuat
34、ionzone. The localized effects of a criticality acci-dent, and the fact that rapid evacuation is notwithout risk, may result in an immediate evac-uation zone that is significantly smaller thanan entire site.5.2 Emergency response plan5.2.1An emergency response plan, consistent withthe documented acc
35、ident evaluation requiredin Sec. 5.1.1, shall be established and main-tained. The emergency response plan may forman integral part of, or be separate from, otherplans.5.2.2The emergency response plan shall include guid-ance to management, technical staff, and re-sponse personnel for response to a cr
36、iticalityAmerican National Standard ANSI0ANS-8.23-20072accident. The plan shall address recommendedprotective actions, functions of response person-nel, and equipment needed for criticality acci-dent response.5.2.3The emergency response plan shall identify po-tential criticality accident locations a
37、nd in-clude appropriate facility descriptions.5.2.4The emergency response plan shall include pro-visions for1! an emergency coordinator;2! activating emergency response;3! responding to concurrent emergenciesforexample, fire, personnel injury, or securityincidents!;4! identifying exposed personnel a
38、nd deter-mining their radiation dose;5! appropriate medical care for exposedpersonnel;6! evaluating the consequences of the crit-icality accident, including those from radio-active and nonradioactive hazardousmaterials that might be released as a resultof the accident;7! determining when the emergen
39、cy condi-tion no longer exists;8! coordinating with emergency organiza-tions expected to provide emergency re-sponse assistance. These organizations maybe onsite or off-site;9! assembly and accountability of personnel.5.2.5The emergency response plan may be activatedon any indication that a critical
40、ity accident isdeveloping, is occurring, or has occurred.5.3 Equipment5.3.1Appropriate protective clothing and equipmentshall be provided for response personnel. Thisclothing and equipment can include respira-tory protection equipment, anticontaminationsuits, both high-range and low-range gammaradia
41、tion detection equipment, neutron detec-tion equipment, communications equipment, andpersonal monitoring devices such as self-reading pocket dosimeters!.5.3.2Appropriate monitoring equipment to deter-mine if further evacuation is needed and toidentify exposed individuals shall be providedfor use at
42、personnel assembly stations!.6 Evacuation6.1When an evacuation is initiated, all personnelwithin the immediate evacuation zone shallevacuate without hesitation by planned evacu-ation routes to an established assembly stationor stations!.6.2Radiation levels shall be monitored in occupiedareas adjacen
43、t to the immediate evacuation zoneafter initiation of the emergency response.6.3Radiation levels shall be monitored periodi-cally at the assembly stations! after initiationof the emergency response.6.4If the monitoring required by Secs. 6.2 and 6.3indicates that the dose rate exceeds 1 mSv0h2!100 mr
44、em0h! in areas that continue to be oc-cupied, nonemergency response personnel shallbe evacuated from those areas.6.5Sufficient exits from the immediate evacuationzone shall be provided to enable rapid and un-obstructed evacuation of personnel. Immediateevacuation for personnel protection shall takep
45、recedence over contamination control or secu-rity considerations.2!The measurement 1 mSv0h derives from Table 22.1, on page 48, “Recommendations on Limits for Exposureto Ionizing Radiation,” NCRP Report No. 91, June 1, 1987.American National Standard ANSI0ANS-8.23-200736.6Assembly stations shall be
46、clearly identified orposted.6.7Evacuation routes should be planned to mini-mize the total risk considering all potentialhazards, for example, chemical, industrial, andradiation.7 Reentry, rescue, andstabilization7.1All activities associated with reentry, rescue,and stabilization shall be coordinated
47、 and au-thorized by the emergency coordinator. Theemergency coordinator may delegate authorityto other qualified individuals.7.2Reentry shall be planned to minimize risks topersonnel. The possibility of a continuing orrecurring criticality accident shall be considered.7.3Reentry during the emergency
48、 shall only bemade by personnel trained in emergency re-sponse and reentry.7.4Personnel who reenter the immediate evacua-tion zone during the emergency shall be in-formed of the potential hazards and shall chooseto accept the associated risk. Reentry shouldbe performed by more than one person.7.5Ree
49、ntry should be made only if a preliminaryradiological survey indicates that the radiationlevels are acceptable for reentry. Existing in-strumentation or temporary sensors with re-mote readout may be used.7.6All reentries shall be made with continuousradiation monitoring. Both neutron and gammainstruments should be used.7.7If personnel need to be rescued, the rescue shallbe planned so as not to expose rescuers to life-threatening radiation doses.7.8If the system remains critical and is possiblycausing excessive damage or significant re-leases of rad
