ANSI ASME OM CODE CASES-2015 Code Cases to OM CODE Code for Operation and Maintenance of Nuclear Power Plants.pdf

1、ASME OM CODE CASESOM CODE CASES(FOR DIVISION 1)A Code Case is the official method of handling a reply to an inquiry when study indicatesthat the Code wording needs clarification, or when the reply modifies the existing requirementsof the Code, or grants permission to use alternative methods.ASME has

2、 agreed to publish Cases issued by the Operation and Maintenance Committeeconcerning the OM Code. Code Cases remain in effect for the applicable editions and addendauntil they are annulled. Cases are published on the ASME Web site under the OM CommitteePage at go.asme.org/OMcommittee as they are iss

3、ued.In July 2006, the Committee approved the elimination of Code Case expiration dates. Anypublished Code Case that has not been annulled and that had an expiration date that is afterJuly 2006 is not expired and may continue to be used. The following Code Cases (with simplified/shortened titles) rem

4、ain in effect and are being published without expiration dates. The latestedition of each Code Case is listed. All previous revisions are included before the latest revision.OMN-1, Revision 1 MOVsOMN-3 Safety Significance Categorization Using Risk InsightsOMN-4 Risk Insights Check ValvesOMN-6 Digita

5、l InstrumentsOMN-7 Risk Insights Pump TestingOMN-8 Control ValvesOMN-9 Pump Curve TestingOMN-10 Safety Significance Testing of SnubbersOMN-11 Risk Insights MOVsOMN-12 Risk Insights Pneumatically/Hydraulically Operated ValvesOMN-13, Revision 2 Extending Snubber Visual ExaminationsOMN-15, Revision 2 E

6、xtending Snubber Operational Readiness TestingOMN-16, Revision 1 Use of a Pump Curve for TestingOMN-17 Alternative Rules Class 1 Pressure/Safety ValvesOMN-18 Alternate Rules Pumps Tested Within 20% of Design FlowOMN-19 Alternative Upper Limit for the Comprehensive Pump TestOMN-20 Inservice Test Freq

7、uencyOMN-21 Alternative Requirements for Adjusting Hydraulic Parameters toSpecified Reference PointsSUMMARY OF CHANGESThe Code Cases affected by this edition are as follows:Page Code Case ChangeC-48 OMN-13, Revision 2 In Table 1, right column head correctedby errata to read 2011C-59 OMN-16 Fig. 1 ad

8、ded by errataC-62 OMN-16, Revision 1 Fig. 1 added by errataC-1INTENTIONALLY LEFT BLANKC-2ASME OM CODE CASESCode Case OMN-1Alternative Rules for Preservice and Inservice Testing of Active Electric Motor-Operated Valve Assembliesin Light-Water Reactor Power PlantsInquiry: What alternative rules, to th

9、ose of OM Code,Subsection ISTC, may be used for preservice and inser-vice testing to assess the operational readiness of activeelectric motor-operated valve assemblies in light-waterreactor power plants?Reply: It is the opinion of the Committee that, in lieuof the rules for preservice and inservice

10、testing to assessthe operational readiness of active electricmotor-operated valve assemblies in light-water reactorpower plants in OM Code-1995, except for leakage ratetesting, the following alternative requirements may beapplied. Electric motor-operated valves for which seatleakage is limited to a

11、specific maximum amount in theclosed position for fulfillment of their required function(Category A) must also be seat leakage rate tested inaccordance with the requirements of the OM Code.NOTE: The terms “shall consider” and “shall be considered” areused in paras. 3.6.2, 3.7.1, and 9.1 of this Code

12、 Case. The CodeCase does not dictate how the considerations in the paragraphsare implemented or documented. Users of the Code Case willdetermine the best methods based on their programs, which mayinclude procedures, checklists, training, or other methods.1 INTRODUCTION1.1 ScopeThis Code Case establi

13、shes the requirements for pre-service and inservice testing to assess the operationalreadiness of active motor-operated valves (MOVs) inlight-water reactor (LWR) power plants.The MOVs covered are those required to perform anactive function in shutting down a reactor to the safeshutdown condition, in

14、 maintaining the safe shutdowncondition, or in mitigating the consequences of anaccident.This Code Case establishes test methods, test inter-vals, parameters to be measured and evaluated, accept-ance criteria, corrective actions, and recordsrequirements.1.2 ExclusionsSee para. ISTC-1200.2 SUPPLEMENT

15、AL DEFINITIONSmotor-operated valve (MOV): a valve and its associatedelectric motor-driven mechanism for positioning theC-3valve, including components that control valve actionand provide position output signals.MOV functional margin: the increment by which anMOVs available capability exceeds the cap

16、abilityrequired to operate the MOV under design basisconditions.stem factor: the ratio of stem torque to stem thrust inrising-stem valves.full-cycleexercise: full stroke of the valve from and backto its initial position.3 GENERAL REQUIREMENTS3.1 Design Basis Verification TestA one-time test shall be

17、 conducted to verify the capa-bility of each MOV to meet its safety-related design basisrequirements. This test shall be conducted at conditionsas close to design basis conditions as practicable.Requirements for a design basis verification test arespecified in applicable regulatory documents. Testin

18、gthat meets the requirements of this Code Case but con-ducted before implementation of this Code Case maybe used.(a) Design basis verification test data shall be usedin conjunction with preservice test data as the basis forinservice test criteria.(b) Design basis verification testing shall be con-du

19、cted in situ or in a prototype test facility that dupli-cates applicable design basis conditions. If a test facilityis used, an engineering analysis shall be documentedthat supports applicability to the in situ conditions.(c) Justification for testing at conditions other thandesign basis conditions

20、and for grouping like MOVsshall be documented by an engineering evaluation, alter-nate testing techniques, or both. Where design basistesting of the specific MOV being evaluated is impracti-cable, or not meaningful (provides no additional usefuldata), data from other MOVs may be used if justifiedby

21、engineering evaluation. Sources for the data includeother plant MOVs or test data published in industrytesting programs. Where analytical techniques are usedto verify design basis capability, those techniques shallbe justified by an engineering evaluation.(d) For certain valve types (e.g., ball, plu

22、g, and dia-phragm valves) where the need for design basis verifica-tion testing has not been previously identified, anASME OM CODE CASESengineering evaluation of operating experience may beused to verify design basis capability.(e) The design basis verification test shall be repeatedif an MOV applic

23、ation is changed, the MOV is physicallymodified, or the system is modified in a manner thatinvalidates its current design basis verification testresults or data. A determination that a design basis veri-fication test is still valid shall be justified by an engi-neering evaluation, alternative testin

24、g techniques, orboth.3.2 Preservice TestEach MOV shall be tested during the preservice testperiod or before implementing inservice testing. Thesetests shall be conducted under conditions as near aspracticable to those expected during subsequent inser-vice testing. Testing that meets the requirements

25、 of thisCode Case but conducted before implementation of thisCode Case may be used. Only one preservice test ofeach MOV is required unless, as described in para. 3.4,the MOV has undergone maintenance that could affectits performance.3.3 Inservice TestInservice testing shall commence when the MOV isr

26、equired to be operable to fulfill its required function(s),as described in para. 1.1, and shall be sufficient to assesschanges in MOV functional margin consistent withsection 6.(a) MOVs may be grouped for inservice testing asdescribed in para. 3.5.(b) Inservice tests shall be conducted in the as-fou

27、ndcondition. Activities shall not be conducted if they inval-idate the inservice test results. If maintenance is neededbetween the inservice tests, see para. 3.4. As-found test-ing is not required prior to maintenance activities aslong as the MOV is not due for an inservice test. Ifmaintenance activ

28、ities are scheduled concurrently withan MOVs inservice test, then the inservice test shallbe conducted in the as-found condition, prior to themaintenance activity.(c) The inservice testing program will include a mixof static and dynamic MOV performance testing. Themix of MOV performance testing may

29、be altered whenjustified by an engineering evaluation of test data.(d) Dynamic MOV performance testing is notrequired for certain valve types (e.g., ball, plug, anddiaphragm valves), with acceptable operatingexperience.(e) Remote position indication shall be verified locallyduring inservice testing

30、or maintenance activities.3.3.1 Inservice Test Interval(a) The inservice test interval shall be determined inaccordance with para. 6.4.4.(b) If insufficient data exist to determine the inservicetest interval in accordance with para. 6.4.4, then MOVC-4inservice testing shall be conducted every two re

31、fuelingcycles or 3 yr (whichever is longer) until sufficient dataexist, from an applicable MOV or MOV group, to justifya longer test interval.(c) The maximum inservice test interval shall notexceed 10 yr. MOV inservice tests conducted perpara. 3.4 may be used to satisfy this requirement.3.4 Effect o

32、f MOV Replacement, Repair, orMaintenanceWhen an MOV or its control system is replaced,repaired, or undergoes maintenance that could affectthe valves performance, new inservice test values shallbe determined or the previously established inservicetest values shall be confirmed before the MOV isreturn

33、ed to service. If the MOV was not removed fromservice, inservice test values shall be immediately deter-mined or confirmed. This testing is intended to demon-strate that performance parameters, which could beaffected by the replacement, repair, or maintenance, arewithin acceptable limits. The Owners

34、 program shalldefine the level of testing required after replacement,repair, or maintenance. Deviations between the previousand new inservice test values shall be identified andanalyzed. Verification that the new values representacceptable operation shall be documented as describedin section 9, Reco

35、rds and Reports.3.5 Grouping of MOVs for Inservice TestingGrouping MOVs for inservice testing is permissible.Grouping MOVs shall be justified by an engineeringevaluation, alternative testing techniques, or both. Thefollowing shall be satisfied when grouping MOVs:(a) MOVs with identical or similar mo

36、tor operatorsand valves and with similar plant service conditionsmay be grouped together based on the results of designbasis verification and preservice tests. Functionality ofall groups of MOVs shall be validated by appropriateinservice testing of one or more representative valves.(b) Test results

37、shall be evaluated and justified for allMOVs in the group.3.6 MOV Exercising Requirements3.6.1 Normal Exercising Requirements. All MOVs,within the scope of this Code Case, shall be full-cycleexercised at least once per refueling cycle with the maxi-mum time between exercises to be not greater than24

38、 months. Full-cycle operation of an MOV, as a resultof normal plant operations or Code requirements, maybe considered an exercise of the MOV, if documented.If full-stroke exercising of an MOV is not practical duringplant operation or cold shutdown, full-stroke exercisingshall be performed during the

39、 plants refueling outage.3.6.2 Additional Exercising Requirements. TheOwner shall consider more frequent exercising require-ments for MOVs in any of the following categories:(a) MOVs with high risk significanceASME OM CODE CASES(b) MOVs with adverse or harsh environmentalconditions or(c) MOVs with a

40、ny abnormal characteristics (opera-tional, design, or maintenance conditions)3.7 Risk-Informed MOV Inservice TestingRisk-informed MOV inservice testing that incorpo-rates risk insights in conjunction with performance mar-gin to establish MOV grouping, acceptance criteria,exercising requirements, and

41、 testing interval may beimplemented.3.7.1 Risk-Informed Considerations. The Ownershall consider the following when incorporating riskinsights in the inservice testing of MOVs:(a) develop an acceptable risk basis for MOV riskdetermination(b) develop MOV screening criteria to determine eachMOVs contri

42、bution to risk(c) finalize risk category by a documented evaluationfrom a plant expert panel3.7.2 Risk-Informed Criteria. Each MOV shall beevaluated and categorized using a documented riskranking methodology. This Code Case provides testrequirements for High and Low Safety SignificantComponent (HSSC

43、/LSSC) categories. If an Ownerestablished more than two risk categories, then theOwner shall evaluate the intermediate SSCs and selectHSSC or LSSC test requirements for those intermedi-ate SSCs.3.7.2.1 HSSC MOVs. HSSC MOVs shall be testedin accordance with para. 3.3 and exercised in accordancewith p

44、ara. 3.6 of this Code Case. HSSC MOVs that canbe operated during plant operation shall be exercisedquarterly, unless the potential increase in core damagefrequency (CDF) and large early release (LER) associatedwith a longer exercise interval is small.3.7.2.2 LSSC MOVs. In meeting the provisions ofth

45、is Code Case, including exercising in accordance withpara. 3.6 and the determination of proper MOV testinterval in section 6, risk insights shall be applied toinservice testing of LSSC MOVs by the following:(a) LSSC grouping shall be technically justified, butthe provision for similarity in subpara.

46、 3.5(a) may berelaxed. The provisions in subpara. 3.5(b) related to eval-uation of test results for MOVs in that group continueto be applicable to all MOVs within the scope of thisCode Case.(b) LSSC MOVs may be associated with an estab-lished group of other MOVs. When a member of thatgroup is tested

47、, the test results shall be analyzed andevaluated in accordance with section 6 and applied toall LSSC MOVs associated with that group.(c) LSSC MOVs that are not associated with an estab-lished group shall be inservice tested in accordance withC-5para. 3.3 using an initial test interval of three refu

48、elingcycles or 5 yr (whichever is longer) until sufficient dataexist to determine a more appropriate test interval asdescribed in para. 6.4.4.(d) LSSC MOVs shall be inservice tested at least every10 yr in accordance with para. 3.3.1.4 TO BE PROVIDED AT A LATER DATE5 TEST METHODS5.1 Test Prerequisite

49、sAll testing shall be conducted in accordance withplant-specific technical specifications, installationdetails, acceptance criteria, and maintenance, surveil-lance, operation, or other applicable procedures.5.2 Test ConditionsInservice test conditions shall be sufficient to deter-mine the MOVs functional margin per para. 6.4. Testconditions shall be recorded for each test per section 9.5.3 Limits and Precautions(a) MOV exposure to dust, moisture, or other adverseconditions shall be minimized when normally enclosedcompartment covers are removed while performingtests.(b) Manu