1、ASME/ANS RA-Sa2009Addenda toASME/ANS RA-S2008Standard forLevel 1/Large EarlyRelease FrequencyProbabilistic RiskAssessment forNuclear Power PlantApplicationsAN AMERICAN NATIONAL STANDARDA01531ASME is the registered trademark of The American Society of Mechanical Engineers.This code or standard was de
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8、SME/ANS RA-Sa2009Following approval by the ASME/ANS RA-S Committee and ASME, and after public review,ASME/ANS RA-Sa2009 was approved by the American National Standards Institute onFebruary 2, 2009.Addenda to the 2008 edition of ASME/ANS RA-S are issued in the form of replacement pages.Revisions, add
9、itions, and deletions are incorporated directly into the affected pages. It is advisable,however, that this page, the Addenda title and copyright pages, and all replaced pages be retainedfor reference.SUMMARY OF CHANGESThis is the first Addenda to be published to ASME/ANS RA-S2008. This Standard has
10、 beenrevised in its entirety.Replace or insert the pages listed. Changes given below are identified on the pages by a margindesignator, (a), placed next to the affected area.Page Location Changeiii, iii.1 Contents Updated to reflect Addenda1 Part 1 Revised in its entirety40 Part 2 Revised in its ent
11、irety115 Part 3 Revised in its entirety131 Part 4 Revised in its entirety215 Part 5 Added257 Part 6 Added271 Part 7 Added286 Part 8 Added301 Part 9 Added315 Part 10 AddedSPECIAL NOTE:The Interpretations to ASME/ANS RA-S, volume 2, are included in this addenda beginning withpage I-5 for the users con
12、venience.(c)INTENTIONALLY LEFT BLANK(d)CONTENTSForeword ivPreparation of Technical Inquires to the Committee on Nuclear Risk Management . vCommittee Roster . viPreface viiiPART 1 GENERAL REQUIREMENTS FOR A LEVEL 1 PRA, INCLUDING LARGE EARLYRELEASE FREQUENCY 1Section 1-1 Introduction . 1Section 1-2 A
13、cronyms and Definitions . 8Section 1-3 Risk Assessment Application Process . 20Section 1-4 Risk Assessment Technical Requirements . 26Section 1-5 PRA Configuration Control 28Section 1-6 Peer Review . 29Section 1-7 References . 31Nonmandatory Appendix1-A PRA Maintenance, PRA Upgrade, and the Advisabi
14、lity of PeerReview . 32PART 2 REQUIREMENTS FOR INTERNAL EVENTS AT-POWER PRA 40Section 2-1 Overview of Internal Events At-Power PRA Requirements At-Power 40Section 2-2 Internal Events PRA Technical Elements and Requirements . 41Section 2-3 Peer Review for Internal Events At-Power 111Section 2-4 Refer
15、ences . 113PART 3 REQUIREMENTS FOR INTERNAL FLOOD AT-POWER PRA . 115Section 3-1 Overview of Internal Flood PRA Requirements At-Power . 115Section 3-2 Internal Flood PRA Technical Elements and Requirements 116Section 3-3 Peer Review for Internal Flood PRA At-Power 130PART 4 REQUIREMENTS FOR FIRES AT-
16、POWER PRA 131Section 4-1 Risk Assessment Technical Requirements for Fire Events At-Power 131Section 4-2 Fire PRA Technical Elements and Requirements 134Section 4-3 Peer Review for Fire PRA At-Power 196Section 4-4 References . 199Nonmandatory Appendix4-A FPRA Methodology 200PART 5 REQUIREMENTS FOR SE
17、ISMIC EVENTS AT-POWER PRA . 215Section 5-1 Overview of Seismic PRA Requirements At-Power 215Section 5-2 Technical Requirements for Seismic PRA At-Power . 217Section 5-3 Peer Review for Seismic Events At-Power 249Section 5-4 References . 250Nonmandatory Appendix5-A Seismic Probabilistic Risk Assessme
18、nt Methodology: Primer 252PART 6 REQUIREMENTS FOR SCREENING AND CONSERVATIVE ANALYSIS OFOTHER EXTERNAL HAZARDS AT-POWER . 257Section 6-1 Approach for Screening and Conservative Analysis . 257Section 6-2 Technical Requirements for Screening and Conservative Analysis . 258iiiSection 6-3 Peer Review fo
19、r Screening and Conservative Analysis 265Section 6-4 References . 266Nonmandatory Appendix6-A List of External Hazards Requiring Consideration 267PART 7 REQUIREMENTS FOR HIGH WIND EVENTS AT-POWER PRA. 271Section 7-1 Overview of High Wind PRA Requirements At-Power 271Section 7-2 Technical Requirement
20、s for High Wind Events PRA At-Power . 272Section 7-3 Peer Review for High Wind PRA At-Power . 284Section 7-4 References . 285PART 8 REQUIREMENTS FOR EXTERNAL FLOOD EVENTS AT-POWER PRA . 286Section 8-1 Overview of External Flood PRA Requirements At-Power . 286Section 8-2 Technical Requirements for Ex
21、ternal Flood Events PRA At-Power . 287Section 8-3 Peer Review for External Flood PRA At-Power . 299Section 8-4 References . 300PART 9 REQUIREMENTS FOR OTHER EXTERNAL HAZARDS AT-POWER PRA . 301Section 9-1 Overview of Requirements for Other External HazardsPRAs At-Power . 301Section 9-2 Technical Requ
22、irements for Other External Hazards PRA At-Power . 303Section 9-3 Peer Review for Other External PRA At-Power . 313Section 9-4 References . 314PART 10 SEISMIC MARGIN ASSESSMENT REQUIREMENTS AT-POWER 315Section 10-1 Overview of Requirements for Seismic Margins At-Power . 315Section 10-2 Technical Req
23、uirements for Seismic Margin At-Power . 316Section 10-3 Peer Review for Seismic Margins At-Power . 325Section 10-4 References . 326Nonmandatory Appendices10-A Seismic Margin Assessment Methodology: Primer 32710-B Seismic Margin Assessment Applications Guidance, IncludingSeismic Margin Assessment Wit
24、h Enhancements . 334iii.1INTENTIONALLY LEFT BLANKFOREWORDThe ASME Board on Nuclear Codes and Standards (BNCS) and American Nuclear Society(ANS) Standards Board mutually agreed in 2004 to form a Nuclear Risk Management CoordinatingCommittee (NRMCC). This committee was chartered to coordinate and harm
25、onize Standardsactivities related to probabilistic risk assessment (PRA) between the two Standards developmentorganizations (SDO). A key activity resulting from NRMCC was the development of PRA Stan-dards structured around the Levels of PRA (i.e., Level 1, Level 2, Level 3) to be jointly issued byth
26、e two societies.The scope of the initial issue of the ASME RA-S standard included Level 1 and Large EarlyRelease Frequency (LERF) for internal events at power. In parallel with the development of ASMERA-S, ANS was developing companion PRA Standards covering external events, internal fire,and low pow
27、er and shutdown conditions. These Standards are ANSI/ANS-58.212003, ANSI/ANS-58.232007, and ANS-58.22 (in development), respectively. ANS-58.22 will be added onceit is approved as a revision or addendum. The three existing Standards are assembled togetheras a revision to ASME RA-S. Consequently, thi
28、s revision to ASME RA-S is being issued with therevised identity of ASME/ANS RA-S2008.A major objective of the combined Standard is to ensure consistency in format, organization,language, and level of detail of the Standard. In assembling the component Standards the followingcriteria were used:(a) t
29、he requirements in the Standards would not be revised or modified(b) no new requirements would be included(c) the numbering scheme of the technical requirements would be preserved(d) the common requirements across the Standards would be consolidated into a single place(e) the commentary and nonmanda
30、tory requirements would be retainedImplementation of the consensus process for this Standard revealed that preserving the exactsame requirements from the component Standards created certain technical issues that will needto be addressed in a revision or addendum of ASME/ANS RA-S2008.During the devel
31、opment of the ASME RA-S and the ANS companion, titled PRA Standardsfor Internal Fires, External Events, and Low Power and Shutdown Conditions, concerns wereraised by stakeholder organizations and SDOs with respect to stability and consistency in require-ments between the Standards. Thus, a key objec
32、tive of this Standard is to improve consistencyand foster stability by enabling future changes to be applied across the various PRA scopes thatpreviously existed as separate Standards. It is anticipated that efficiencies and improvements willresult from maintaining, interpreting, and implementing on
33、e PRA Standard as opposed to fourseparate Standards. Additionally, the identification of common processes in general requirementssections for such areas as PRA configuration control, peer review, maintenance versus upgrade,and use in risk-informed applications can now be provided, which further supp
34、orts consistencyand stability. Using a single committee responsible for this Standard provides a single point ofresponse to inquiries and places the expertise necessary to address and coordinate activities ina single cognizant group supported by responsible technical societies. In addition, this Sta
35、ndardis intended to determine the technical adequacy of a PRA such that the PRA can be used indecision making.The Committee on Nuclear Risk Management (CNRM) operates under procedures accreditedby the American National Standards Institute (ANSI) as meeting the criteria of consensus proce-dures for A
36、merican National Standards. The initial Standard was approved by the ASME Boardon Nuclear Codes and Standards and subsequently approved by ANSI on April 9, 2008.CNRM is responsible for ensuring that this Standard is maintained and revised as necessaryfollowing its original publication. This includes
37、 appropriate coordination with and linkage toother Standards under development for related risk-informed applications.ivASME/ANS RA-Sa2009PART 1GENERAL REQUIREMENTS FORA LEVEL 1 PRA, INCLUDINGLARGE EARLY RELEASEFREQUENCYSection 1-1Introduction1-1.1 OBJECTIVEThis Standard sets forth the requirements
38、for probabi-listic risk assessments (PRAs) used to support risk-informed decisions for commercial light water reactornuclear power plants and prescribes a method forapplying these requirements for specific applications.1-1.2 SCOPE AND APPLICABILITYThis Standard establishes requirements for a Level 1
39、PRA of internal and external hazards for all plantoperating modes (low power and shutdown modes willbe included at a future date). In addition, this Standardestablishes requirements for a limited Level 2 PRA suffi-cient to evaluate large early release frequency (LERF).The only hazards explicitly exc
40、luded from the scopeare accidents resulting from purposeful human-inducedsecurity threats (e.g., sabotage). This Standard appliesto PRAs used to support applications of risk-informeddecision-making related to design, licensing, procure-ment, construction, operation, and maintenance. Theserequirement
41、s are written for operating power plants.They may be used for plants under design or construc-tion, for advanced LWRs, or for other reactor designs,but revised or additional requirements may be needed.This version of the PRA Standard provides specificrequirements for the following hazard groups:(a)
42、Internal Events (Part 2)(b) Internal Floods (Part 3)1(c) Internal Fires (Part 4)(d) Seismic Events (Part 5)(e) High Winds (Part 7)(f) External Floods (Part 8)Technical requirements for PRAs of other external haz-ards that may be relevant on a plant-specific basis or forspecific applications are prov
43、ided in Part 9. In additionto providing technical requirements for detailed PRAsof these hazards, this Standard provides requirementsfor screening and conservative analyses of external haz-ards (Part 6), and technical requirements for seismicmargin analysis are provided in Part 10.Many of the techni
44、cal requirements in Part 2 are fun-damental requirements for performing a PRA for anyhazard group, and are therefore relevant to Parts 3through 9 of this Standard. They are incorporated byreference in those requirements that address the devel-opment of the plant response to the damage states cre-ate
45、d by the hazard groups addressed in Parts 3 through9. Their specific allocation to Part 2 is partially a histori-cal artifact of the way this PRA Standard was developed,with the at-power internal events (including internalfloods) requirements being developed first, and thoseof the remaining hazard g
46、roups being developed later.However, it is also a reflection of the fact that a funda-mental understanding of the plant response to a reason-ably complete set of initiating events (as defined in 1-2.2)provides the foundation for modeling the impact of vari-ous hazards on the plant. Hence, even thoug
47、h Part 2 is(a)ASME/ANS RA-Sa2009given a title associated with the internal events hazardgroup it is understood that the requirements in this Partare applicable to all the hazard groups within the scopeof the PRA.1-1.3 STRUCTURE FOR PRA REQUIREMENTS1-1.3.1 PRA ElementsThe technical requirements for t
48、he PRA model areorganized by their respective PRA technical elements.The PRA elements define the scope of the analysis foreach Part of the Standard. This Standard specifies techni-cal requirements for the PRA elements listed inTable 1-1.3-1.1-1.3.2 High-Level RequirementsA set of objectives and HLRs
49、 is provided for eachPRA Element in the Technical Requirements section ofeach respective Part of this Standard. The HLRs set forththe minimum requirements for a technically acceptablebaseline PRA, independent of an application. The HLRsare defined in general terms and present the top levellogic for the derivation of more detailed SRs. The HLRsreflect not only the diversity of approaches that havebeen used to develop the existing PRAs, but also theneed to accommodate future technological innovations.1-1.3.3 Supporting RequirementsA set of SRs is provided for each HLR (that is prov
