L-MT-22-006, 10 CFR 50.55a Request Associated with the Monticello Sixth Inservice Testing Ten-Year Interval OMN-26 (L-MT-22-006): Difference between revisions

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{{#Wiki_filter:W EB-BASED PROP OS ED ALTER NATI VE SUB MIS SI ON 10 CF R 50. 55a( z )( 1)
{{#Wiki_filter:Submission Date: February 18, 2022 Submitted By: Mary Emanuelson Document Sensitivity: Non-Sensitive Licensee: Xcel Energy Plant Unit(s) and Docket No(s): Monticello (05000263)
Sub m ission Dat e: Fe brua r y 18, 2022 Sub m itt e d By: Mar y Ema nue lson Doc um en t S en sit ivit y: Non-Se nsitive Lic en see : Xc el Ener gy Pl ant Uni t( s) an d Doc ke t No( s): Monti ce llo (05000263)
Project
L ice ns ee Cont ac t:Ma r y Ema nuel son m ar y.e ma nuelson@xc el ene rgy. com
( 612) 330-5850


Pr oj ec t Tit le :
==Title:==
10 CF R 50.55a R eque st Assoc ia ted with the Montic e llo S ixth I nser vic e Testi ng Te n-Yea r I nte rva l OMN-26 ( L-MT-22-006)
10 CFR 50.55a Request Associated with the Monticello Sixth Inservice Testing Ten-Year Interval OMN-26 (L-MT-22-006)
Proposed Alternative Number or Identifier:
VR-07 Request Type:
10 CFR 50.55a(z)(1)
Inservice Inspection (ISI) or Inservice Testing (IST)
Inservice Testing (IST)
Requested Completion Date:
February 28, 2023 Brief Description of Proposed Alternative Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter 'NSPM', hereby requests NRC authorization of this 10 CFR 50.55a request to support the implementation of the sixth IST ten-year interval for Monticello Nuclear Generating Plant (MNGP). Proposed Relief Request VR-07 requests to adopt American Society of Mechanical Engineers (ASME) Code Case OMN-26,
'Alternate Risk-Informed and Margin Based Rules for Inservice Testing of Motor Operated Valves [MOVs].'
Proposed Duration of Alternative (in terms of ISI/IST Program Interval with Start and End Dates):
This request, upon approval, will be applied to the MNGP sixth IST ten-year interval starting October 1, 2022 and is scheduled to end May 31, 2032.
Applicable ASME Code Requirements The following paragraphs and subparagraphs in Mandatory Appendix III of the ASME OM Code are affected by this Request to adopt Code Case OMN-26.Appendix III, III-3310 'lnservice Test Interval', subparagraph (c): 'The maximum inservice test interval shall not exceed 10 yr.
MOV inservice tests conducted per para. III-3400 may be used to satisfy this requirement.'Appendix III, III-3700 'Risk-Informed MOV Inservice Testing'. Risk-informed MOV inservice testing that incorporates risk insights in conjunction with performance margin to establish MOV grouping, acceptance criteria, exercising requirements and testing interval may be implemented. Appendix III, Subparagraph III-3721,
'[High Safety Significant Component (HSSC)] MOVs': 'HSSC MOVs shall be tested in accordance with para. III-3300 and exercised in accordance with para. III-3600 HSSC MOVs that can be operated during plant operation shall be exercised quarterly, unless the potential increase in core damage frequency (CDF) and large early release (LER) associated with a longer exercise interval is small.'Appendix III, III-3722 '[Low Safety Significant Component (LSSC)] MOVs', subparagraph (d): 'LSSC MOVs shall be inservice tested at least every 10 yr. in accordance with para. III-3310.'
Applicable American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPV Code), or ASME Operation and Maintenanceâ-of Nuclear Power Plants (OM Code), Edition and Addenda ASME OM Code, Operation and Maintenance of Nuclear Power Plants, 2017 Edition with no Addenda.
Current ISI or IST Program Interval Number and Start/End Dates MNGP is currently on its fifth IST ten-year interval that is scheduled to end on September 30, 2022. The MNGP sixth IST ten-year interval begins on October 1, 2022.
Applicable ASME Code Components and/or System Description Active safety related MOVs that are required by Subsection ISTC of the 2017 Edition of the ASME OM Code to be tested in accordance with Appendix III entitled Preservice and Inservice Testing of Active Electric Motor-Operated Valve Assemblies in Water-cooled Reactor Nuclear Power Plants.


Pr opose d Alt er nat ive Num be r or Id en tif ie r:
===Reason for Request===
VR-07
In accordance with 10 CFR 50.55a(z)(1), NSPM is requesting approval to adopt OMN-26 in conjunction with implementing Mandatory Appendix III as part of the 2017 Edition of the OM Code at the MNGP.
Code Case OMN-26 better aligns the inservice test intervals in Mandatory Appendix III to the Risk and Margin Based Licensee MOV Programs developed in response to NRC Generic Letter 96-05, 'Periodic Verification of Design-Basis Capability of Safety-Related Motor Operated Valves,' that have been in effect since 1998. There is no formal technical basis in Appendix III for limiting the maximum inservice test interval to 10 years. Code Case OMN-26 establishes a structured risk-informed approach for determining inservice intervals that provides WEB-BASED PROPOSED ALTERNATIVE SUBMISSION 10 CFR 50.55a(z)(1)
Licensee


Re qu est Type :
==Contact:==
10 CF R 50.55a (z ) (1)
Mary Emanuelson mary.emanuelson@xcelenergy.com (612) 330-5850


Inse rvic e In spe ct ion ( ISI) or Inse rvi ce T est ing ( IST )
an acceptable level of quality and safety while providing NSPM additional inservice test schedule flexibility Full Description of Proposed Alternative NSPM proposes to implement OMN-26 alternative risk and margin informed rules for inservice testing of MOVs in its entirety at MNGP as described below:
Inse rvi ce Te sting (I ST)
Proposed Alternative to III-3310(c)
The maximum inservice test interval shall not exceed 10 years unless Risk Informed Inservice Testing under the alternative provisions of Code Case OMN-26 to para. III-3700. MOV inservice tests conducted per para. III-3400 may be used to satisfy this requirement.
Proposed Alternative to III-3700 Risk-informed MOV inservice testing that incorporates risk insights in conjunction with MOV Functional Margin to establish MOV grouping, acceptance criteria, exercising requirements and test interval may be implemented.
Proposed Alternative to III-3721 HSSC MOVs shall be tested in accordance with para. III-3300 and exercised in accordance with para. III-3600 while applying the following HSSC MOV Risk insights and limitations.
a) HSSC MOVs that can be operated during plant operation shall be exercised quarterly, unless the potential increase in core damage frequency (CDF) and large early release (LER) associated with a longer exercise interval is small.
b) For HSSC MOVs, the maximum inservice test interval shall be established in accordance with Table 1 of OMN-26 as shown below.
Table 1 HSSC MOV - Margin Based Maximum Inservice Test Intervals OMN-26 Table 1 Notes:
(A) Occurs at a periodicity no less frequent than once a refueling outage.
(B) To utilize these intervals, test strokes at or exceeding design basis system conditions must be in the applicable safety function direction(s) and have no applicable operating experience, degradation, or diagnostic test anomaly with the potential for adverse impact on MOV functional margin or the capability of the MOV to perform its design basis function.
(D) For the purpose of this code case, the MOV functional margin limits apply to the As-Left MOV condition at the start of the inservice test interval and include applicable test uncertainties and allowance for service-related degradation.
Proposed Alternative to III-3722 (d)
For LSSC MOVs, the maximum inservice test interval shall be established in accordance with Table 2 of OMN-26, as shown below.
Table 2 LSSC MOV - Margin Based Maximum Inservice Test Intervals HSSC MOV Functional Margin(D)
Maximum lnservice Test Interval (Years)
If MOV is routinely(A) operated at Design Basis Pressure Conditions-Max lnservice Test Interval (Years)(B)
Low (< 5%)
2 4
Medium ( 5% and < 10%)
4 9
High ( 10% and < 20%)
9 9
Very High ( 20%)
9 12 LSSC MOV Functional Margin(D)
Maximum Inservice Test Interval (Years)
If MOV is routinely(A) operated at Design Basis Pressure Conditions-Max lnservice Test Interval (Years)(B)
Low (< 5%)
4 9
Medium ( 5% and < 10%)
9 12 High ( 10% and < 20%)
12 12


Re qu est e d Com pl et ion Date :
OMN-26 Table 2 Notes:
Febr ua ry 28, 2023
(A) Occurs at a periodicity no less frequent than once a refueling outage.
(B) To utilize these intervals, test strokes at or exceeding design basis system conditions must be in the applicable safety function direction(s) and have no applicable operating experience, degradation, or diagnostic test anomaly with the potential for adverse impact on MOV functional margin or the capability of the MOV to perform its design basis function.
(C) Operating plants that have acquired the requisite test data to satisfy Appendix III, paragraphs III-3310(b) or III-3722(c) must complete once cycle of collecting diagnostic test data at an extended test interval, minimum 9 and maximum 12 years, before extending the test interval by engineering evaluation to the maximum 16-year test interval.
(D) For the purpose of this code case, the MOV functional margin limits apply to the As-Left MOV condition at the start of the inservice test interval and include applicable test uncertainties and allowance for service-related degradation.
Description of Basis for Use The requested relief to adopt OMN-26 is in line with the current Joint Owners Group (JOG) MOV Periodic Verification (PV) Test Program implemented at MNGP in response to NRC Generic Letter 96-05. Both the JOG MOV PV Program and Code Case OMN-26 provide a Risk-Margin based methodology that establishes limitations for maximum inservice test intervals for MOVs. Code Case OMN-26 simply provides a reasonable extension of this Risk-Informed philosophy based on the lessons learned and accumulated MOV performance data gathered during MOV Performance Verification Testing. Appendix III alone, isolated from OMN-26, provides no such methodology other than a maximum limit for the inservice test interval regardless of Risk or Margin.
The requested allowed maximum inservice test intervals are modest extensions with many of the Low Risk MOVs extending from 10 to 12 years (20% increase). This test interval change can be readily adopted with no loss of MOV performance and/or safety system reliability provided that no adverse performance trends are indicated. MNGP's MOV Performance Trending Governance will ensure that only MOV's with good performance history, high stable margins and no adverse diagnostic trends would be candidates for the OMN-26 based inservice test interval extensions.
The requested High Margin Maximum interval changes afforded by OMN-26 align with NSPM's desire to adopt a divisional MOV outage testing strategy that reduces the implementation burden of MOV lnservice Testing and allows greater flexibility in optimizing safety system availability. The current six and ten-year JOG Program based High-Margin Maximum Intervals do not support this strategy.
The requested relief reduces the maximum test interval for HSSC MOVs allowed by Appendix III from ten years to nine years commensurate with Risk Informed Methodology. Further under this relief request, NSPM will treat MNGP MOVs currently classified as Medium Risk by the 3-Tier JOG Risk Ranking as HSSC thereby providing more rigorous periodic verification requirements for the applicable valves especially those with less than high margin.
The requested relief takes credit for routine design basis differential pressure testing (DBDPT) of MOVs to justify extending the maximum Inservice test interval to 12 Years for Very High Margin HSSC MOVs and 16 years for Very High Margin LSSC MOVs.
With the exception of Low Risk MOVs routinely operated at design basis differential pressure (D-P) conditions, Code Case OMN-26 does not allow maximum MOV Inservice Test intervals to exceed ten years unless the associated MOVs are classified as High Margin or Very High Margin. Most High Risk MOVs are limited to four years or less for Low/Medium Margins and most Low Risk MOVs are limited to nine years or less for Low/Medium Margins. Code Case OMN-26 provides more rigorous requirements targeted specifically to Low/Medium Margin MOVs than currently allowed under Appendix III. This Risk/Margin approach is in line with accepted Risk-Informed Strategies such as the JOG MOV PV Program.
For the majority of applicable MOVs (i.e., those MOVs not subject to periodic stroking under design basis D-P conditions), the Code Case limited the scope to only High Margin Valves for extending test intervals incrementally beyond current limits:
Test intervals for High Risk MOVs go from six to nine years Test intervals for Low Risk MOVs go from ten to twelve years (Note: Twelve years is aligned for all Boiling Water Reactor nuclear power plants (BWRs) with either 18-or 24-month refueling cycles).
The Table below provides a detailed comparison of the Maximum MOV Test Intervals for the JOG MOV Program, Mandatory Appendix III and Code Case OMN-26 that NSPM seeks to adopt at MNGP via this relief request. MOVs identified with Bold and Underline type have maximum MOV inservice test intervals exceeding the current Appendix III ten-year limit.
Table 3 MNGP Maximum MOV Test Intervals Based on Code Case OMN-26 Very High ( 20%)
12 16(c)


Bri ef De scr ipt ion of Pr opose d Alt er nat ive Nor the rn St ate s P ower C ompany, a M innesot a cor por ati on, doing busi ness as Xce l Ene r gy ( her e af ter 'NS PM', her e by r eque sts NR C author iz ati on of t his 10 CF R 50. 55a r eque st to suppor t the impl eme nta tion of the sixt h I ST ten-ye ar int er val f or Montic e llo Nuc le ar Ge ner at ing Pla nt ( MNGP). Pr opose d Re lie f Re que st VR-07 re quest s t o a dopt Ame ri ca n S ocie ty of Me cha nica l Engi nee rs ( AS ME) Code C ase OMN-26,
OMN-26 Table 3 Notes:
'Alte r nate R isk-Inf or med and Ma rgin Ba se d Rul es for Inse rvi ce Te sting of Motor Ope ra te d Val ves [M OVs].'
(A) Code Case Maximum Inservice Test Intervals for all Low/Medium Margin MOVs are less than or equal to current ten-year Appendix III limit. (i.e., Code Case is more conservative than Appendix III for Low/Medium Margin MOVs).
(B) Code Case Maximum Inservice Test Intervals for Low/Medium Margin HSSC MOVs are equal to the current JOG MOV PV Program limits of two/four years respectively. (Code Case intervals are aligned with JOG MOV).
(C) Code Case Maximum Inservice Test Intervals for Low/Medium Margin LSSC MOVs (four/nine years) are less than the current JOG MOV PV Program Limits of six/ten years respectively.
(D) The following four categories of MOVs have maximum inservice test intervals that exceed the current ten-year limit:
: a. High Margin, LSSC MOVs (12 years)
: b. Very High Margin, HSSC MOVs that are periodically stroked at design basis DP conditions (DBDPT) (12 years)
: c. Medium Margin, LSSC MOVs that are periodically DBDPT (12 years)
: d. Very High Margin, LSSC MOVs that are periodically DBDPT (16 years)
(E) Except for Low Margin HSSC MOVs, the Maximum MOV Inservice Test Intervals are optimized for Divisional Outage Scheduling (i.e.,
4, 9, 12, 16 years). Twelve years is optimal for both BWRs and supports both 18-month and 24-month refueling outages.
(F) To utilize these intervals, test strokes at or exceeding design basis system conditions must occur at a periodicity no less frequent than once a refueling cycle, must be in the applicable safety function direction(s), and the MOV must have no applicable operating experience, degradation or diagnostic test anomaly with the potential for adverse impact on MOV functional margin or the capability of the MOV to perform its design basis function. These routine strokes during the inservice test interval are not required to be diagnostically monitored.
(G) Operating plants that have acquired the requisite test data to satisfy Appendix III, paragraphs III-3310(b) or III-3722(c) must complete one cycle of collecting diagnostic test data at an extended test interval, minimum 9 and maximum 12 years, before extending the test interval by engineering evaluation to the maximum 16-year test interval.
(H) The MOV functional margin limits apply to the As-Left MOV condition at the start of the inservice test interval and includes applicable test uncertainties and allowance for service-related degradation. The inservice test interval is uniquely established for each MOV based on margin and risk classification of the MOV.
Describe Hardship or Unusual Difficulty NOT APPLICABLE Any Additional Information (submission attachments listed here)


Pr opose d Dur ati on of Alte rn at ive (i n te rm s of ISI/ IST Pr ogram In te r val wit h St art and En d Date s) :
NOT USED (No Attachments)
Thi s r eque st, upon appr oval, wi ll be appli ed to t he MNGP si xth I ST te n-ye ar i nter va l st ar ting Octobe r 1, 2022 and is s che duled to end May 31, 2032.
Precedents H.B Robinson Steam Electric Plant, Unit 2 &#xe2; SER for Proposed Alternative Request IST-RR-9 Regarding the Sixth 10-Year Interval Inservice Testing Program, dated November 4, 2021 (ADAMS Accession Number ML21259A099). Braidwood Units 1 and 2, Calvert Cliffs Units 1 and 2, Clinton Power Station, RE Ginna, Limerick Generating Station Units 1 and 2, Nine Mile Point Units 1 and 2, Peach Bottom Units 2 and 3 - SER for Proposed Alternative to Utilize Code Case OMN-26, dated September 1, 2020 (ADAMS Accession Number ML20232A171).
 
References
Ap pli cab le ASM E Cod e Req uir em en t s The f oll owing pa ra gra phs and subpar agr a phs in Ma ndator y Appe ndix I I I of the AS ME OM C ode ar e a ff ec te d by this Re quest to adopt Code Case OMN-26.Appe ndix I I I, I I I-3310 ' lnse r vice Te st Int er val ', subpa r agr aph (c ) : ' The ma ximum inse rvi ce te st inte rva l shall not exc e ed 10 yr.
: 1. ASME OM Code Case OMN-26, Alternate Risk-Informed and Margin Based Rules for Inservice Testing of Motor Operated Valves.}}
MOV inse rvic e te sts conduc te d pe r par a. I I I-3400 may be used to sat isf y this r equi re ment.' Appendix I II, I II-3700 ' Risk-I nfor me d MOV Inse rvi ce Te sting'. Ris k-inf or me d MOV inse r vice t est ing t hat inc orpor at es ri sk ins ights in c onjunc tion wi th pe rf or manc e ma rgi n to es tabl ish MOV groupi ng, ac ce ptanc e c rit er ia, exe rc ising r equir e ments a nd te sting inte r val ma y be im plem ente d. Appendix II I, Subpa ra gr aph II I-3721,
'[ High S af e ty S ignif ic ant Compone nt (HSS C) ] MOVs' : ' HSS C M OVs shal l be t este d i n a cc orda nc e wi th pa r a. I II-3300 a nd e xer ci sed in ac cor danc e with par a. I I I-3600 HS SC MOVs tha t ca n be ope r ate d dur ing plant ope ra tion shal l be e xe rc ise d qua rte r ly, unle ss t he potent ial incr ea se in cor e da mage f r eque ncy ( CDF) a nd la r ge ea rl y r el ea se (LER ) assoc ia te d with a longe r exe rc ise i nter va l is sma ll. ' Appe ndix II I, II I-3722 ' [Low S af e ty S ignif ic ant Compone nt (LS SC )] MOVs', subpar a gra ph ( d) : ' LSS C MOVs sha ll be inser vic e te ste d a t le a st e ver y 10 yr. in ac cor danc e with par a. I I I-3310.'
 
Ap pli cab le Ame ri can S ocie ty of M ec han ical En gin ee rs (AS ME ) Boil er an d Pr es sur e Vesse l Cod e (B PV Code ), or AS ME Op er ati on and Main te nan ce &#xe2;-of Nuc le ar Powe r Plant s (O M Cod e), Ed it ion and Add en da AS ME OM Code, Ope ra tion and Ma inte nanc e of Nucle ar Power Pla nts, 2017 Edi tion wi th no Addenda.
 
Cu rr en t IS I or IS T Pr ogr am Int er val Nu m be r and St ar t/ End Dat es MNGP is cur r ent ly on its fi ft h I ST ten-yea r int er val tha t is s che duled to end on S epte mbe r 30, 2022. The MNGP sixth IS T t en-yea r inte r val be gins on Oc tober 1, 2022.
 
Ap pli cab le ASM E Cod e Comp one nt s an d/or Syst em De scr ip tion Ac tive sa f ety r ela te d MOVs t hat ar e r equir e d by Subse ct ion I STC of the 2017 Edition of the AS ME OM Code to be tes ted in a c cor danc e with Appe ndix II I e ntitle d Pr e ser vic e and Ins er vice Te sting of Act ive Ele ctr ic Mot or-Oper at ed Va lve Asse mblie s in W at er-c oole d R ea ctor Nuc le ar Power P la nts.
 
Re ason f or Re qu est In ac cor danc e with 10 C FR 50.55a ( z) (1), NSP M i s r eque sting a pprova l t o a dopt OMN-26 in conj uncti on with imple me nting Manda tor y Appe ndix II I a s pa rt of the 2017 Edition of the OM Code a t t he MNGP.
 
Code Ca se OMN-26 bett er a ligns the ins er vic e test int er val s in Ma nda tor y Appe ndix I I I to the Ris k a nd Ma rgi n Ba se d Lic ense e MOV Pr ogra ms deve loped in re sponse to NRC Gene ri c Le tte r 96-05, 'P er iodi c Ve r ifi ca tion of Design-Ba sis Ca pabi lity of Sa f ety-Re la ted Motor Ope ra te d Va lves, ' tha t have be en in e f fe ct sinc e 1998. Ther e is no f or ma l te c hnica l basis in Appendix II I f or li miting the ma ximum inse r vice test int er val to 10 ye ar s. Code Ca se OMN-26 est abli shes a str uct ure d r isk-inf orm ed appr oac h for de te rmi ning i nser vic e inte rva ls that pr ovide s an ac ce ptabl e leve l of qual ity and saf et y while pr oviding NSP M a dditiona l inse rvic e te st sche dule f lexi bilit y
 
Fu ll Desc rip t ion of Prop osed Alt e rn ative NS PM propos es to i mple ment OMN-26 al ter na tive r isk and mar gin inf orme d r ule s for i nser vic e tes ting of MOVs in its enti re ty at MNGP a s de sc ri bed below:
 
Pr opose d Alt er nat ive t o III-3310( c)
 
The m axim um i nser vic e tes t int er val sha ll not e xce e d 10 yea rs unle ss R isk Inf or med Ins er vice Te sting unde r the al ter na tive pr ovisions of Code Case OMN-26 t o pa ra. II I-3700. MOV inse r vice t ests c onducte d pe r pa ra. I II-3400 ma y be use d t o sa tisf y t his re quir eme nt.
 
Pr opose d Alt er nat ive t o III-3700
 
Risk-inf orm ed MOV inse rvic e te sting tha t i ncor pora te s r isk insight s in conj uncti on with MOV Func tiona l Mar gin to e sta blish MOV gr ouping, ac ce ptanc e c rit er ia, exe rc ising r equir em ents a nd te st inte rva l may be impl eme nte d.
 
Pr opose d Alt er nat ive t o III-3721
 
HS SC MOVs sha ll be te ste d in ac cor da nce with par a. II I-3300 and exe rc ise d i n a cc orda nce wit h pa ra. I II-3600 while a pplying the f ollowing HS SC MOV R isk i nsights and limi tat ions.
 
a) HS SC MOVs that c an be oper at ed during pla nt ope r ati on sha ll be exe rc ise d qua r ter ly, unle ss the pote ntia l i ncr ea se in cor e dam age fr eque ncy ( CDF) a nd l ar ge ea r ly r el ea se ( LER )ass ocia te d with a longe r exe r cise i nter va l i s sma ll.
 
b) F or HSSC MOVs, the m axim um ins er vic e test int er val sha ll be est ablis hed in a cc or danc e with Ta ble 1 of OMN-26 as shown be low.
 
T abl e 1
 
HSS C MO V - M ar gin Base d Maxim um Inse rvi ce T est In t er vals
 
HSS C MOV Func tiona l Maxim um l nser vic e Test I f MOV is rout inel y(A) ope ra te d a t De sign Ma r gin(D) I nte rva l ( Yea r s) Ba sis Pr e ssure C onditions-Max lnse rvi ce Tes t I nte rva l (Ye ar s)(B)
 
Low ( < 5% ) 2 4 Me dium ( 5% a nd < 10%) 4 9 High ( 10% a nd < 20% ) 9 9 Ver y Hi gh ( 20%) 9 12
 
OMN-26 T able 1 Note s:
 
(A) Occ urs a t a pe ri odici ty no le ss f r eque nt t han once a r e fue lingoutage.
 
(B) To utiliz e the se inte r vals, t est str oke s a t or exc ee ding de sign basi s syst em condi tions must be in the appl ica ble sa fe ty func tion dir ec tion( s) and have no appli ca ble oper a ting experience, de gr ada tion, or di agnosti c test a nomal y with the pote ntia l for a dve rse i mpac t on MOV f unct ional mar gin or the c apa bilit y of the M OV to pe r for m its design bas isf unc tion.
 
(D) F or the pur pose of this code ca se, the MOV func tiona l mar gin limi ts a pply to t he As-Le ft MOV c ondition at the st ar t of the inser vic e te st i nter va l a nd i nclude a pplic abl e tes t unc er ta intie s and all owa nce f or se r vice-r e lat ed degr ada tion.
 
Pr opose d Alt er nat ive t o III-3722 (d )
 
For LSS C MOVs, the ma ximum inse rvic e te st inte rva l s hall be e sta bl ishe d in ac cor da nce with Tabl e 2 of OMN-26, as shown be low.
 
Tab le 2
 
LSS C M OV - Mar gin Base d Maxi mu m Inse r vice T est I nt er vals
 
LS SC MOV Func tiona l Mar gin(D) Ma ximum I nser vic e Test I f MOV i s r outine ly(A) oper at ed at Desi gn Int er val ( Ye a rs) B asi s P re ssur e Condit ions-Ma x lns er vice Te st Int er val ( Ye ar s)(B)
 
Low ( < 5% ) 4 9 Me dium ( 5% a nd < 10%) 9 12 High ( 10% a nd < 20% ) 12 12 Ver y Hi gh ( 20%) 12 16( c)
 
OMN-26 T able 2 Note s:
 
(A) Occ urs a t a pe ri odici ty no le ss f r eque nt t han once a r e fue lingoutage.
 
(B) To utiliz e the se inte r vals, t est str oke s a t or exc ee ding de sign basi s syst em condi tions must be in the appl ica ble sa fe ty func tion dir ec tion( s) and have no appli ca ble oper a ting experience, de gr ada tion, or di agnosti c test a nomal y with the pote ntia l for a dve rse i mpac t on MOV f unct ional mar gin or the c apa bilit y of the M OV to pe r for m its design bas isf unc tion.
 
(C) Oper a ting plant s tha t have a cqui re d the r e quisite t est da ta to sati sfy Appendix I II, par a gra phs I I I-3310( b) or I II-3722(c ) must c omple te onc e c ycle of coll ec ting diagnost ic te st da ta a t an exte nded te st i nter va l, mini mum 9 and ma ximum 12 ye ar s, be for e e xtendi ng the t est inte r val by e nginee ri ng e valua tion to the ma ximum 16-ye a r tes t i nter val.
 
(D) For the pur pose of t his c ode c ase, the MOV f unct ional ma rgi n li mits appl y to the As-Lef t M OV condit ion a t the sta rt of the i nser vic e te st inter va l a nd i nclude a pplic abl e tes t unc er ta intie s and all owa nce for se r vice-re la ted degr a dation.
 
De scr ip ti on of Basis f or Us e The r e queste d re lie f to adopt OMN-26 is i n li ne wi th t he cur re nt Joint Owne r s Gr oup ( JOG) MOV Pe ri odic Ver if ica tion ( PV) Test P rogr am imple ment ed at MNGP in r es ponse to NR C Ge ner ic Le tte r 96-05. B oth t he JOG MOV PV Pr ogr am and Code C ase OMN-26 pr ovide a Ri sk-Mar gin base d me thodology tha t e sta blishe s l imit ati ons f or ma ximum inse rvi ce te st inte rva ls for MOVs. C ode Ca se OMN-26 simply provi des a re asona ble e xtens ion of t his R isk-Inf or med philos ophy ba sed on the l essons le ar ne d a nd a cc umula ted MOV pe rf or manc e dat a gathe r ed duri ng MOV Pe rf or manc e Ver if ic ati on Tes ting. Appendi x I II a lone, isola te d f rom OMN-26, pr ovide s no suc h me thodology othe r than a ma ximum limit f or the inse r vice t est inte r val r ega rdl ess of Ri sk or Ma r gin.
The r e queste d allowe d m aximum ins er vice test int er vals a re m odest ext ensi ons with ma ny of the Low Risk MOVs e xtendi ng f rom 10 to 12 ye ar s ( 20% inc r ea se). This tes t int er val c hange c an be r ea dily adopte d wit h no loss of MOV per f orm anc e and/or saf et y syst em re lia bilit y pr ovided tha t no adve r se per f orm anc e tre nds ar e indic at ed. MNGP' s MOV Pe rf or manc e Tr ending Gover nanc e will ensur e that only MOV' s wi th good per f orm anc e histor y, high stabl e mar gins and no a dve rse di agnosti c tr ends woul d be c andi date s f or the OMN-26 ba se d inse r vice t est inte r val ext ensions.
The r e queste d Hi gh Ma rgi n Ma ximum inte rva l cha nges af f orde d by OMN-26 al ign with NSP M's de sir e to a dopt a divisiona l MOV out age t esti ng str a tegy tha t r e duce s the i mple ment ati on bur den of MOV lnse r vice Te sting and al lows gr ea te r f lexi bility in optimi zing saf et y syst em ava ila bilit y. The cur re nt six and ten-ye ar JOG P rogr a m ba se d High-Mar gin Maxi mum Inte r vals do not suppor t this stra te gy.
The r e queste d re lie f r educ es the ma ximum te st i nter va l f or HSS C MOVs a llowed by Appe ndix I I I fr om te n ye ar s t o nine ye ar s comme nsur at e wi th R isk I nf orm ed Met hodology. Fur the r under t his r e lie f re que st, NSP M will tr e at MNGP MOVs cur r ently c lass ifi ed as Medi um R isk by the 3-Tier JOG Risk Ra nking as HS SC the r eby provi ding mor e r igor ous pe ri odic ver if ic at ion r equi re me nts f or the applic a ble val ves espe ci all y those wit h le ss than high mar gin.
The r e queste d re lie f ta kes cr edi t f or r outine de sign basi s dif f er ent ial pr ess ure te sti ng ( DB DPT) of MOVs to jus tif y e xtendi ng the maxim um I nse rvi ce te st inte rva l to 12 Yea rs f or Ver y High Mar gin HSSC MOVs and 16 ye ar s f or Ve ry Hi gh Ma r gin LS SC MOVs.
With the e xce ption of Low Ri sk MOVs routi nely oper a ted at de sign ba sis dif fe r enti al pr essur e ( D-P ) condit ions, Code C ase OMN-26 doe s not a llow maxi mum MOV Inse r vice Te st inte rva ls to e xce e d te n ye ar s unles s the a ssoc iat ed MOVs a re c la ssif ied as High Ma rgin or Ver y High Mar gin. Most Hi gh Ri sk MOVs ar e limi ted to four ye ar s or le ss f or Low/Me dium Mar gins and most Low Ri sk MOVs a r e limit ed to ni ne yea rs or le ss for Low/Me dium Margins. Code C ase OMN-26 pr ovide s mor e r igor ous r equi re me nts t ar get ed spec if ica lly to Low/Me dium Mar gin MOVs tha n c urr e ntly all owe d unde r Appendi x I II. This Risk/ Mar gin appr oac h i s in line wit h a cc epte d Risk-Inf orm ed Str a tegi es such as the JOG M OV PV Pr ogram.
 
For the m ajor ity of a pplic able MOVs (i.e., those M OVs not s ubjec t to pe ri odic str oking under de sign basi s D-P condit ions), the Code Case limit ed the sc ope to onl y High Mar gin Va lve s f or e xtendi ng te st inte rva ls incr e ment all y be yond c urr ent li mits:
Te st inte rva ls for Hi gh Ri sk MOVs go f rom six to nine yea r s Te st inte rva ls for Low Risk MOVs go fr om ten to twelve ye ar s (Note : Twel ve yea rs is al igned for all Boi ling Wa ter Rea c tor nuc le ar powe r pla nts (B WRs ) wi th e ithe r 18-or 24-month r e fue ling cyc le s).
The Ta ble be low pr ovide s a de tai led com par ison of the Ma ximum MOV Te st I nte rva ls for the JOG MOV P rogr am, Manda tor y Appe ndix II I a nd Code C ase OMN-26 tha t NS PM se eks to adopt at MNGP via this r eli ef r eque st. MOVs ide ntif ie d with Bol d an d Un de rli ne type ha ve ma ximum MOV inse r vice t est inte r vals e xce eding the c urr e nt Appe ndix I I I ten-ye ar l imit.
 
T able 3
 
MNGP Maxim um MOV Tes t Int er vals Base d on Code Case OM N-26 OMN-26 T able 3 Note s:
 
(A) Code C ase Ma ximum I nser vic e Test I nter va ls for a ll Low/ Medi um Ma r gin MOVs ar e le ss tha n or equa l t o c urr e nt t en-yea r Appendix I II limit. (i. e., Code C ase i s mor e c onser va tive tha n Appe ndix I I I for Low/M edium Ma rgi n MOVs).
 
(B) Code Cas e Maxim um I nse rvi ce Te st I nte rva ls for Low/M edium Ma rgi n HSS C MOVs ar e e qual to the cur r ent JOG MOV P V P rogr am limit s of t wo/ four ye ar s re spe cti vely. (C ode Ca se inte rva ls ar e a ligne d with JOG MOV).
 
(C) Code Cas e Maxim um I nse rvi ce Te st I nte rva ls for Low/M edium Ma rgi n LSS C MOVs ( four /nine ye ar s) a r e les s tha n t he cur re nt JOG MOV PV P rogr a m Lim its of six/t en yea rs r espe ct ively.
 
(D) The foll owi ng f our ca te gori es of MOVs ha ve ma ximum inse rvic e te st inte rva ls that e xce ed the cur r ent te n-ye a r limi t:
: a. High Mar gin, LSS C MOVs ( 12 ye ar s)
: b. Ve ry High M ar gin, HSS C MOVs tha t a re pe r iodic all y str oke d a t de sign basi s DP c onditions (DB DP T) (12 ye ar s)
: c. Me dium Mar gin, LSS C MOVs tha t ar e per iodic al ly DB DP T ( 12 ye ar s)
: d. Ve ry High M ar gin, LSS C MOVs tha t a r e per iodic al ly DBDP T ( 16 ye ar s)
 
(E) Exce pt f or Low Ma r gin HS SC MOVs, the Ma ximum MOV I nser vic e Test I nter val s a r e optimiz ed f or Divisiona l Out age S che duling (i. e.,
4, 9, 12, 16 ye ar s). Twelve ye a rs is optima l for bot h BW Rs and suppor ts both 18-month and 24-m onth r e fue ling outage s.
 
(F ) To utili ze the se inte r vals, test str oke s a t or exc ee ding design bas is sys tem c onditions must occ ur a t a pe r iodic ity no le ss f r eque nt than once a re fue ling cyc le, must be in the appl ica ble sa fe ty func tion dir ec tion( s), and the MOV must ha ve no a pplic able ope r ati ng e xper ie nce,
de gr ada tion or dia gnostic te st anom aly with t he pote nt ial f or a dver se impa ct on MOV func tiona l mar gin or the c apa bilit y of t he MOV to pe r for m its desi gn ba sis func tion. These r outine s troke s during the ins er vice test int er val a re not r equir e d to be dia gnostic all y moni tore d.
 
(G) Ope r ati ng pla nts that ha ve ac quir ed the r equisi te te st da ta t o sa tisf y Appe ndix I I I, pa r agr aphs I II-3310( b) or I I I-3722( c) m ust c omple te one cyc le of c olle cting dia gnostic t est dat a at an e xtende d t est inte r val, m inimum 9 a nd m axim um 12 yea r s, bef ore exte nding the te st i nter va l by engine er ing eva lua tion t o the m axim um 16-ye ar te st inte rva l.
 
(H) The MOV func tiona l mar gin limi ts a pply to t he As-Le ft MOV c ondition at the st ar t of the inse rvi ce te st inte rva l and inc ludes appl ica ble test unc er ta intie s a nd a llowa nce f or se rvi ce-r e lat ed degr ada tion. The inse rvic e te st inte rva l i s uni quely est abli shed for ea ch MOV bas ed on mar gin and ri sk c las sif ica tion of the MOV.
 
De scr ib e Hard shi p or Un us ual Di ff ic ult y NOT AP PLI CABLE
 
An y Add it ional In for m ation ( su bm ission at t ach me nt s list ed h er e)
NOT US ED (No Atta chme nts)
 
Pr ec e de nt s H. B Robinson Ste a m Ele ct ri c Pla nt, Unit 2 &#xe2;SER f or Pr opose d Alte rna tive R eque st IS T-R R-9 Re ga rding the S ixth 10-Ye ar I nte rva l Inse rvi ce Te sting Pr ogra m, da te d Novem ber 4, 2021 (ADAMS Acc essi on Numbe r ML21259A099). B ra idwood Units 1 and 2, Cal ver t Clif f s Unit s 1 and 2, Cli nton P ower S tat ion, RE Gi nna, Lime r ick Gene ra ting St ati on Units 1 a nd 2, Nine M ile Poi nt Unit s 1 and 2, Pe ac h B ottom Unit s 2 and 3 -SER for Pr oposed Alte rna tive to Utili ze Code C ase OMN-26, dat ed Se ptem ber 1, 2020 (ADAMS Acc essi on Numbe r ML20232A171).
 
Re fe r en ce s
: 1. ASME OM Code C ase OMN-26, Alt er nat e Risk-I nfor me d a nd Ma r gin B ase d R ules f or Ins er vic e Te sti ng of Mot or Ope r ate d Va lve s.}}

Latest revision as of 18:26, 27 November 2024

10 CFR 50.55a Request Associated with the Monticello Sixth Inservice Testing Ten-Year Interval OMN-26 (L-MT-22-006)
ML22049B323
Person / Time
Site: Monticello Xcel Energy icon.png
Issue date: 02/18/2022
From: Emanuelson M
Northern States Power Co, Xcel Energy
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
L-MT-22-006
Download: ML22049B323 (5)
v • d • e


Text

Submission Date: February 18, 2022 Submitted By: Mary Emanuelson Document Sensitivity: Non-Sensitive Licensee: Xcel Energy Plant Unit(s) and Docket No(s): Monticello (05000263)

Project

Title:

10 CFR 50.55a Request Associated with the Monticello Sixth Inservice Testing Ten-Year Interval OMN-26 (L-MT-22-006)

Proposed Alternative Number or Identifier:

VR-07 Request Type:

10 CFR 50.55a(z)(1)

Inservice Inspection (ISI) or Inservice Testing (IST)

Inservice Testing (IST)

Requested Completion Date:

February 28, 2023 Brief Description of Proposed Alternative Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter 'NSPM', hereby requests NRC authorization of this 10 CFR 50.55a request to support the implementation of the sixth IST ten-year interval for Monticello Nuclear Generating Plant (MNGP). Proposed Relief Request VR-07 requests to adopt American Society of Mechanical Engineers (ASME) Code Case OMN-26,

'Alternate Risk-Informed and Margin Based Rules for Inservice Testing of Motor Operated Valves [MOVs].'

Proposed Duration of Alternative (in terms of ISI/IST Program Interval with Start and End Dates):

This request, upon approval, will be applied to the MNGP sixth IST ten-year interval starting October 1, 2022 and is scheduled to end May 31, 2032.

Applicable ASME Code Requirements The following paragraphs and subparagraphs in Mandatory Appendix III of the ASME OM Code are affected by this Request to adopt Code Case OMN-26.Appendix III, III-3310 'lnservice Test Interval', subparagraph (c): 'The maximum inservice test interval shall not exceed 10 yr.

MOV inservice tests conducted per para. III-3400 may be used to satisfy this requirement.'Appendix III, III-3700 'Risk-Informed MOV Inservice Testing'. Risk-informed MOV inservice testing that incorporates risk insights in conjunction with performance margin to establish MOV grouping, acceptance criteria, exercising requirements and testing interval may be implemented. Appendix III, Subparagraph III-3721,

'[High Safety Significant Component (HSSC)] MOVs': 'HSSC MOVs shall be tested in accordance with para. III-3300 and exercised in accordance with para. III-3600 HSSC MOVs that can be operated during plant operation shall be exercised quarterly, unless the potential increase in core damage frequency (CDF) and large early release (LER) associated with a longer exercise interval is small.'Appendix III, III-3722 '[Low Safety Significant Component (LSSC)] MOVs', subparagraph (d): 'LSSC MOVs shall be inservice tested at least every 10 yr. in accordance with para. III-3310.'

Applicable American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPV Code), or ASME Operation and Maintenanceâ-of Nuclear Power Plants (OM Code), Edition and Addenda ASME OM Code, Operation and Maintenance of Nuclear Power Plants, 2017 Edition with no Addenda.

Current ISI or IST Program Interval Number and Start/End Dates MNGP is currently on its fifth IST ten-year interval that is scheduled to end on September 30, 2022. The MNGP sixth IST ten-year interval begins on October 1, 2022.

Applicable ASME Code Components and/or System Description Active safety related MOVs that are required by Subsection ISTC of the 2017 Edition of the ASME OM Code to be tested in accordance with Appendix III entitled Preservice and Inservice Testing of Active Electric Motor-Operated Valve Assemblies in Water-cooled Reactor Nuclear Power Plants.

Reason for Request

In accordance with 10 CFR 50.55a(z)(1), NSPM is requesting approval to adopt OMN-26 in conjunction with implementing Mandatory Appendix III as part of the 2017 Edition of the OM Code at the MNGP.

Code Case OMN-26 better aligns the inservice test intervals in Mandatory Appendix III to the Risk and Margin Based Licensee MOV Programs developed in response to NRC Generic Letter 96-05, 'Periodic Verification of Design-Basis Capability of Safety-Related Motor Operated Valves,' that have been in effect since 1998. There is no formal technical basis in Appendix III for limiting the maximum inservice test interval to 10 years. Code Case OMN-26 establishes a structured risk-informed approach for determining inservice intervals that provides WEB-BASED PROPOSED ALTERNATIVE SUBMISSION 10 CFR 50.55a(z)(1)

Licensee

Contact:

Mary Emanuelson mary.emanuelson@xcelenergy.com (612) 330-5850

an acceptable level of quality and safety while providing NSPM additional inservice test schedule flexibility Full Description of Proposed Alternative NSPM proposes to implement OMN-26 alternative risk and margin informed rules for inservice testing of MOVs in its entirety at MNGP as described below:

Proposed Alternative to III-3310(c)

The maximum inservice test interval shall not exceed 10 years unless Risk Informed Inservice Testing under the alternative provisions of Code Case OMN-26 to para. III-3700. MOV inservice tests conducted per para. III-3400 may be used to satisfy this requirement.

Proposed Alternative to III-3700 Risk-informed MOV inservice testing that incorporates risk insights in conjunction with MOV Functional Margin to establish MOV grouping, acceptance criteria, exercising requirements and test interval may be implemented.

Proposed Alternative to III-3721 HSSC MOVs shall be tested in accordance with para. III-3300 and exercised in accordance with para. III-3600 while applying the following HSSC MOV Risk insights and limitations.

a) HSSC MOVs that can be operated during plant operation shall be exercised quarterly, unless the potential increase in core damage frequency (CDF) and large early release (LER) associated with a longer exercise interval is small.

b) For HSSC MOVs, the maximum inservice test interval shall be established in accordance with Table 1 of OMN-26 as shown below.

Table 1 HSSC MOV - Margin Based Maximum Inservice Test Intervals OMN-26 Table 1 Notes:

(A) Occurs at a periodicity no less frequent than once a refueling outage.

(B) To utilize these intervals, test strokes at or exceeding design basis system conditions must be in the applicable safety function direction(s) and have no applicable operating experience, degradation, or diagnostic test anomaly with the potential for adverse impact on MOV functional margin or the capability of the MOV to perform its design basis function.

(D) For the purpose of this code case, the MOV functional margin limits apply to the As-Left MOV condition at the start of the inservice test interval and include applicable test uncertainties and allowance for service-related degradation.

Proposed Alternative to III-3722 (d)

For LSSC MOVs, the maximum inservice test interval shall be established in accordance with Table 2 of OMN-26, as shown below.

Table 2 LSSC MOV - Margin Based Maximum Inservice Test Intervals HSSC MOV Functional Margin(D)

Maximum lnservice Test Interval (Years)

If MOV is routinely(A) operated at Design Basis Pressure Conditions-Max lnservice Test Interval (Years)(B)

Low (< 5%)

2 4

Medium ( 5% and < 10%)

4 9

High ( 10% and < 20%)

9 9

Very High ( 20%)

9 12 LSSC MOV Functional Margin(D)

Maximum Inservice Test Interval (Years)

If MOV is routinely(A) operated at Design Basis Pressure Conditions-Max lnservice Test Interval (Years)(B)

Low (< 5%)

4 9

Medium ( 5% and < 10%)

9 12 High ( 10% and < 20%)

12 12

OMN-26 Table 2 Notes:

(A) Occurs at a periodicity no less frequent than once a refueling outage.

(B) To utilize these intervals, test strokes at or exceeding design basis system conditions must be in the applicable safety function direction(s) and have no applicable operating experience, degradation, or diagnostic test anomaly with the potential for adverse impact on MOV functional margin or the capability of the MOV to perform its design basis function.

(C) Operating plants that have acquired the requisite test data to satisfy Appendix III, paragraphs III-3310(b) or III-3722(c) must complete once cycle of collecting diagnostic test data at an extended test interval, minimum 9 and maximum 12 years, before extending the test interval by engineering evaluation to the maximum 16-year test interval.

(D) For the purpose of this code case, the MOV functional margin limits apply to the As-Left MOV condition at the start of the inservice test interval and include applicable test uncertainties and allowance for service-related degradation.

Description of Basis for Use The requested relief to adopt OMN-26 is in line with the current Joint Owners Group (JOG) MOV Periodic Verification (PV) Test Program implemented at MNGP in response to NRC Generic Letter 96-05. Both the JOG MOV PV Program and Code Case OMN-26 provide a Risk-Margin based methodology that establishes limitations for maximum inservice test intervals for MOVs. Code Case OMN-26 simply provides a reasonable extension of this Risk-Informed philosophy based on the lessons learned and accumulated MOV performance data gathered during MOV Performance Verification Testing. Appendix III alone, isolated from OMN-26, provides no such methodology other than a maximum limit for the inservice test interval regardless of Risk or Margin.

The requested allowed maximum inservice test intervals are modest extensions with many of the Low Risk MOVs extending from 10 to 12 years (20% increase). This test interval change can be readily adopted with no loss of MOV performance and/or safety system reliability provided that no adverse performance trends are indicated. MNGP's MOV Performance Trending Governance will ensure that only MOV's with good performance history, high stable margins and no adverse diagnostic trends would be candidates for the OMN-26 based inservice test interval extensions.

The requested High Margin Maximum interval changes afforded by OMN-26 align with NSPM's desire to adopt a divisional MOV outage testing strategy that reduces the implementation burden of MOV lnservice Testing and allows greater flexibility in optimizing safety system availability. The current six and ten-year JOG Program based High-Margin Maximum Intervals do not support this strategy.

The requested relief reduces the maximum test interval for HSSC MOVs allowed by Appendix III from ten years to nine years commensurate with Risk Informed Methodology. Further under this relief request, NSPM will treat MNGP MOVs currently classified as Medium Risk by the 3-Tier JOG Risk Ranking as HSSC thereby providing more rigorous periodic verification requirements for the applicable valves especially those with less than high margin.

The requested relief takes credit for routine design basis differential pressure testing (DBDPT) of MOVs to justify extending the maximum Inservice test interval to 12 Years for Very High Margin HSSC MOVs and 16 years for Very High Margin LSSC MOVs.

With the exception of Low Risk MOVs routinely operated at design basis differential pressure (D-P) conditions, Code Case OMN-26 does not allow maximum MOV Inservice Test intervals to exceed ten years unless the associated MOVs are classified as High Margin or Very High Margin. Most High Risk MOVs are limited to four years or less for Low/Medium Margins and most Low Risk MOVs are limited to nine years or less for Low/Medium Margins. Code Case OMN-26 provides more rigorous requirements targeted specifically to Low/Medium Margin MOVs than currently allowed under Appendix III. This Risk/Margin approach is in line with accepted Risk-Informed Strategies such as the JOG MOV PV Program.

For the majority of applicable MOVs (i.e., those MOVs not subject to periodic stroking under design basis D-P conditions), the Code Case limited the scope to only High Margin Valves for extending test intervals incrementally beyond current limits:

Test intervals for High Risk MOVs go from six to nine years Test intervals for Low Risk MOVs go from ten to twelve years (Note: Twelve years is aligned for all Boiling Water Reactor nuclear power plants (BWRs) with either 18-or 24-month refueling cycles).

The Table below provides a detailed comparison of the Maximum MOV Test Intervals for the JOG MOV Program, Mandatory Appendix III and Code Case OMN-26 that NSPM seeks to adopt at MNGP via this relief request. MOVs identified with Bold and Underline type have maximum MOV inservice test intervals exceeding the current Appendix III ten-year limit.

Table 3 MNGP Maximum MOV Test Intervals Based on Code Case OMN-26 Very High ( 20%)

12 16(c)

OMN-26 Table 3 Notes:

(A) Code Case Maximum Inservice Test Intervals for all Low/Medium Margin MOVs are less than or equal to current ten-year Appendix III limit. (i.e., Code Case is more conservative than Appendix III for Low/Medium Margin MOVs).

(B) Code Case Maximum Inservice Test Intervals for Low/Medium Margin HSSC MOVs are equal to the current JOG MOV PV Program limits of two/four years respectively. (Code Case intervals are aligned with JOG MOV).

(C) Code Case Maximum Inservice Test Intervals for Low/Medium Margin LSSC MOVs (four/nine years) are less than the current JOG MOV PV Program Limits of six/ten years respectively.

(D) The following four categories of MOVs have maximum inservice test intervals that exceed the current ten-year limit:

a. High Margin, LSSC MOVs (12 years)
b. Very High Margin, HSSC MOVs that are periodically stroked at design basis DP conditions (DBDPT) (12 years)
c. Medium Margin, LSSC MOVs that are periodically DBDPT (12 years)
d. Very High Margin, LSSC MOVs that are periodically DBDPT (16 years)

(E) Except for Low Margin HSSC MOVs, the Maximum MOV Inservice Test Intervals are optimized for Divisional Outage Scheduling (i.e.,

4, 9, 12, 16 years). Twelve years is optimal for both BWRs and supports both 18-month and 24-month refueling outages.

(F) To utilize these intervals, test strokes at or exceeding design basis system conditions must occur at a periodicity no less frequent than once a refueling cycle, must be in the applicable safety function direction(s), and the MOV must have no applicable operating experience, degradation or diagnostic test anomaly with the potential for adverse impact on MOV functional margin or the capability of the MOV to perform its design basis function. These routine strokes during the inservice test interval are not required to be diagnostically monitored.

(G) Operating plants that have acquired the requisite test data to satisfy Appendix III, paragraphs III-3310(b) or III-3722(c) must complete one cycle of collecting diagnostic test data at an extended test interval, minimum 9 and maximum 12 years, before extending the test interval by engineering evaluation to the maximum 16-year test interval.

(H) The MOV functional margin limits apply to the As-Left MOV condition at the start of the inservice test interval and includes applicable test uncertainties and allowance for service-related degradation. The inservice test interval is uniquely established for each MOV based on margin and risk classification of the MOV.

Describe Hardship or Unusual Difficulty NOT APPLICABLE Any Additional Information (submission attachments listed here)

NOT USED (No Attachments)

Precedents H.B Robinson Steam Electric Plant, Unit 2 â SER for Proposed Alternative Request IST-RR-9 Regarding the Sixth 10-Year Interval Inservice Testing Program, dated November 4, 2021 (ADAMS Accession Number ML21259A099). Braidwood Units 1 and 2, Calvert Cliffs Units 1 and 2, Clinton Power Station, RE Ginna, Limerick Generating Station Units 1 and 2, Nine Mile Point Units 1 and 2, Peach Bottom Units 2 and 3 - SER for Proposed Alternative to Utilize Code Case OMN-26, dated September 1, 2020 (ADAMS Accession Number ML20232A171).

References

1. ASME OM Code Case OMN-26, Alternate Risk-Informed and Margin Based Rules for Inservice Testing of Motor Operated Valves.
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