L-97-191, Application for Amend to License NPF-16,extending semi- Annual Surveillance Interval Specified in Table 4.3-2 for Testing ESFAS Subgroup Relays to Interval Consistent W/Ceog Rept CEN-403,Rev 1-A for March 1996
| ML17229A432 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 08/01/1997 |
| From: | Stall J FLORIDA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML17229A433 | List: |
| References | |
| L-97-191, NUDOCS 9708050354 | |
| Download: ML17229A432 (15) | |
Text
CATEGORY 1
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ACCES'D>;ON NBR-:9708050354 DOC.DATE: 97/08/01 NOTARIZED: YES FACIL;'>0-$89 St. Lucie Plant, Unit 2, Florida Power
& Light,Co.
AUTH. NAME AUTHOR AFFILIATION STAt ui J.A.
Florida Power
& Light Co.
RECIP.NAME RECIPIENT AFFILIATION Document, Control Branch (Document Control Desk)
SUBJECT:
Application for amend to license NPF-16,extending semi-annual surveillance interval specified in Table 4.3-2 for testing ESFAS subgroup relays to interval consistent, w/CEOG Rept CEN-403,Rev 1-A for March 1996.
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Florida Power &Light Company, 6501 South Ocean Drive, Jensen Beach, FL 34957 I 97-191 August 1, 1997 ',
10 CFR 50 90 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Rc:
St. Lucie Unit 2 Docket No. 50-389 Proposed License Amendment ESFAS Sub ou Rein Surveillance Rcf:
NRC Lcttcr: Bruce A. Boger, Director, DivisionofReactor Controls and Human Factors to D. F. Pilmer, Chairman, Combustion Enginccring Owners Group,
Subject:
REVIEW OF CE OWNERS GROUP TOPICAL REPORT CEN-403, REVISION 1, "ESFAS SUBGROUP RELAYTEST INTERVAL EXTENSION;" February 27, 1996.
Pursuant to 10 CFR 50.90, Florida Power &LightCompany (FPL) requests to amend Facility Operating Liccnsc NPF-16 for St. Lucie Unit 2 by incorporating thc attached Technical Specifications (TS) revisions.
The amendment willextend thc semi-annual survcillancc interval spccificd in Table 4.3-2 for testing thc Enginccred Safety Features Actuation System (ESFAS) subgroup relays to an interval consistent with Combustion Engineering Owners Group Report CEN-403, Revision 1-A, March, 1996, and its associated safety evaluation (Rcfcrence). It is requested that thc proposed amendment, ifapproved, be issued by Dcccmbcr 1, 1997. is an evaluation ofthe proposed TS changes. is thc "Dctcrmination ofNo Significant Hazards Consideration." Attachment 3 contains a copy ofthc aG'ected TS pages marked-up to show the proposed cllailges.
The proposed amendmcnt has been revicwcd by thc St. Lucie FacilityRcvicw Group and thc Florida Power &
Light Company Nuclear Review Board.
In accordance with 10 CFR 50.91 (b)(1), a copy of thc proposed amcndmcnt is being forwarded to thc State Dcsignce for thc State ofFlorida.
Please contact us ifthere are any questions about this submittal.
Very trulyyours, J. A. Stall Vice Prcsidcnt St. Lucie Plant JAS/RLD Attachments cc: Scc next page 9708050854 97080i PDR ADGCK 05000389 P
PDR an FPL Group company llllllllllllllllllllllllllllllllllllllll
St. Lucic Unit 2 Docket No. 50-389 Proposed License Amendmcnt ESFAS Sub ou Rcla Surveillance L-97-191 Page 2 cc:
Regional Administrator, Region II,USNRC.
Senior Resident Inspector, USNRC, St. Lucie Plant.
Mr. W.A. Passetti, Florida Department ofHealth and Rehabilitative Scrviccs.
'I St. Lucie Unit 2 Docket No. 50-389 Proposed License Amendment ESFAS Sub ou Rcla Surveillance L-97-191 Page 3 STATE OF FLORIDA
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'OUNTYOF ST. LUCIE )
J. A. Stall being first duly sworn, deposes and says:
That hc is Vice President, St. Lucie Plant, for the Nuclear Division ofFlorida Power &Light Company, the Liccnsce herein; That he has exccutcd the foregoing document; that the statements made in this document are true and correct to the best ofhis knowledge, information and belief, and that he is authorized to cxccute the document on behalf ofsaid Liccnscc.
J. A. Stall STATE OF FLORIDA COUNTYOF S'
OC l E Sworn to and subscribed before mc this I
dayof A X
19+7 by J. A. Stall, who is personally known to me.
ignaturc ofNotary Public-State ofFlorida GEORGE R. MADDEN MYCOMMSS IONlce 66202s Bondsd 1hu Notsy Pub5c UndensWe Name ofNotary Public (Print, Type, or Stamp)
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St. Lucie Unit 2 Docket No. 50-389 Proposed License Amendmcnt ESFAS Sub u
Rela Surveillance L-97-191 ATTACHMENT1 EVALUATIONOF PROPOSED TS CHANGES
St. Lucic Unit 2 Docket No. 50-389 Proposed Liccnsc Amendmcnt ESFAS Sub ou Rela Surveillance L-97-191 Pagel of 4 EVALUATIONOF PROPOSED TS CHANGES
'ntroduction The proposed amendment to Facility Operating Liccnsc NPF-16 for St. Lucic Unit 2 (PSL2) willextend the surveillance interval required for the Engineered Safety Fcaturcs Actuation System (ESFAS) subgroup relays from six months to at least once per 18 months (refueling cycle), with testing performed on a staggered test basis.
The mean time between failures (MTBF)for thc PSL2 ESFAS subgroup relays is 84 months.
Thc proposed surveillance interval is based on dcmonstratcd relay reliability and confirmation that the generic analysis contained in Combustion Engineering Owners Group (CEOG) Rcport CEN-403, Revision 1-A, with the plant-spccific clarifications provided in this submittal, is applicable to PSL2.
In a letter and associated safety evaluation transmitted to the CEOG Chairman on Fcbruaiy 27, 1996, the NRC staff approved this topical rcport foruse by liccnsecs as a basis for changes to plant tcchnical specifications.
The staff concluded that thc failure data and analyses prcsentcd therein, and in supporting documents, supports the proposed refueling interval staggered test basis for the subject relays. Approval ofthis amendmcnt willconstitute a tcchnical specification improvcmcnt as described in NUREG-1366, "Improvcmcnts to Tcchnical Specifications Surveillance Rcquircments," and willimprove safety by reducing the amount oftesting performed at power.
Dcscri tionofPro osedTechnicalS ecification S Chan es 0
Copies ofthc affcctcd TS pages, marked-up to show the proposed changes, arc contained in Attachment 3.
TABLE4.3-2 a cs 3/4 3-22 and 3/4 3-23, ENGINEERED SAFETY FEATURES ACTUATIONSYSTEM INSTRUMENTATIONSURVEILLANCEREQUIREMENTS, is revised as follows:
(1) The "SA(2)" surveillance frequency notation shown for thc Automatic Actuation Logic C~EL FUNCTIONALTEST applicable to Safety Injection (SIAS), Containmcnt Spray (CSAS), Containment Isolation (CIAS), Main Stcam Isolation, and Containmcnt Sump Recirculation (RAS), is changed to read "R(3)."
(2) Footnote (3) is added to describe the ESFAS subgroup relay test, which "shall be performed on a STAGGERED TEST BASIS at subintcrvals of6 months, such that each subgroup relay is tested at least once pcr 18 months."
(3) Footnote (2), which willcontinue to apply to the AuxiliaryFcedwatcr (AFAS) Automatic Actuation Logic, is revised to morc accurately reflec terminology associated with AFAS.
Bases 3/4.3.1 and 3/4,3,2 Pa e B 3/4 3-1, REACTOR PROTECTIVE AND ENGINEERED SAFETY FEATURES ACTUATIONSYSTEMS INSTRUMENTATION,is revised to include a ncw paragraph which provides additional information relative to ESFAS subgroup relay testing.
St. Lucic Unit 2 Docket No. 50-389 Proposed License Amendment ESFAS Sub ou Rela" Surveillance L-97-191 Page2of 4 B~ack round Thc ESFAS is designed to initiate automatic operation ofEngineered Safety Features (ESF) components that are required for proper performance ofthe safety injection, containmcnt isolation, containmcnt spray, main stcam isolation, containment sump recirculation, and auxiliaiy fccdwater systems.
Thc ESFAS includes circuitryfor redundant initiatingvariable mcasurcmcnt devices, trip bistablcs, coincidence logic matrices, actuation modules, output (subgroup) relays, and manual and automatic testing.
Individual ESF components are assigned to a specific "group," and each group is actuated by an output (electro-magnetic) relay; hence thc term "subgroup relay." Each subgroup relay operates in response to signals from thc coincidcncc logic matrix and actuation modules, and is cithcr cncrgized at nominal rated voltage or complctcly dc-cncrgizcd, dcpcnding on its normal non-accident state.
As such, the ESFAS subgroup relays are not subject to time-rclatcd instrument drik It should bc noted that ESFAS functions applicable to the auxiliary fecdwatcr system arc pcrformcd by an independent AuxiliaryFccdwatcr Actuation System (AFAS), which consists of circuitry, components, and cabinets dcsigncd and constructed specifically for AFAS.
The current PSL2 Tcchnical Specifications require each ESFAS subgroup relay to be tcstcd on a semi-annual basis.
Thc test includes cncrgization/de-cnergization ofeach relay and verification ofits operability.
In December 1984, the NRC staff cstablishcd the Tcchnical Specifications Improvcmcnt Program (TSIP) to provide the framework for rewriting and improving facilitytcchnical specifications.
As an clcmcnt ofthc TSIP, all TS survcillancc rcquircments were comprchensivcly cxamincd.
Thc results ofthat effort are presented in NUREG-1366, "Improvements to Technical Specifications Surveillance Rcquircmcnts," wherein it is stated, "...
that while some testing at power is essential to verify cquipmcnt and system operability, safety can bc improved, equipment degradation decreased, and unncccssary personnel burden relaxed by reducing thc amount oftesting at power." Relative to ESFAS slave [subgroup] relays, Section 5.2 ofNUREG-1366 states that relay reliability is gcncrally good, that testing thc relays at power contributes to the frcqucncy ofinadvcrtcnt equipmcnt starts and reactor trips, and that the reliabilityofslave relays is a reasonable basis for relaxing test rcquircmcnts.
Thc GEOG Topical Rcport, CEN-403, Revision 1-A, was prcparcd to justify extending thc surveillance test interval forESFAS subgroup relays used in Combustion Engineering (CE) Nuclear Stcam Supply System (NSSS) plants, and documents an analysis ofsubgroup relay performance which included thc PSL2 ESFAS. This effort rcsultcd in the CEOG rccommcndation (withcertain exceptions stated in thc rcport) that thc applicable subgroup relays bc tested at a minimum required frequency of once per fuel cycle, and an endorsement of the rccommcndation in Section 5.2 ofNUREG-1366, "Perform relay [slave relay or sub-group relay] testing on a staggered test basis over a [fuel] cycle and leave the tests carrying highest risk to a rcfucling outage or other cold shutdown." The type ofrelays employed in thc PSL2 AFAS, which is a scparatc system performing the ESFAS functions for auxiliary fecdwater, was not included in the relay failure analysis rcportcd in CEN-403.
The NRC staK found thc CEOG topical rcport acceptable, and further concluded that licensccs rcfcrcncing the rcport as a basis for proposed TS changes should: (1) Confirm applicability ofthc CEN-403, Rcv. 1, analyses fortheir plant, and (2) Confirm that the applicablc sctpoint calculations account for any increase in instrument driltcaused by thc cxtcndcd test interval. In addition, the staff dctcrmincd that iftwo or morc ESFAS subgroup relays fail in a 12-month period, thc liccnsce should consider the design, maintcnancc, and testing ofall ESFAS subgroup relays to cvaluatc the adequacy of the surveillance interval. Ifthc liccnscc dctcrmincs that thc surveillance interval is inadequate for detecting a single relay failure, the survcillancc interval should be dccrcascd such that thc liccnsce can dctcct an ESFAS subgroup relay failure prior to occurrence of a second failure.
St. Lucie Unit 2 Docket No. 50-389 Proposed License Amendmcnt ESFAS Sub ou Rela Surveillance L-97-191 Page3of 4 Bases for Pro osed TS Chan e
Thc proposed TS survcillancc rcquircs testing the ESFAS subgroup relays on a staggered test basis, e.g.,
approximately I/3 ofthc relays willbc tcstcd cvcry 6 months such that each relay is tested at least once pcr 18 months (rcfucling cycle). The staggered test basis provides a reasonable time limitin which common-mode failures could be dctectcd.
The subgroup relays that cannot be tcstcd at power or othe+vise offer the greatest potential for an inadvcrtcnt plant transient willbc tested during a scheduled refueling outage or other plant shutdown. This is consistent with the goal ofreducing the potential ofchallcngcs to safety systems due to testing during power operation.
St. Lucie Unit 2 is one of 15 plants included in a generic comparative analysis of ESFAS subgroup relay performance in CE plants that was conducted by Combustion Engineering.
The analysis addressed the eQcct of ESFAS subgroup relay surveillance test interval extensions on the availability of the ESFAS for two broad classes ofCE plant designs: plants with an ESFAS dcsigncd by CE, and plants with a non-CE ESFAS design.
Thc latter design applies to PSL2. Topical Rcport CEN403, Revision 1-A, summarizes ESFAS subgroup relay performance history for both types ofESFAS design.
Table 1, "ESFAS SUBGROUP RELAYRELIABILITY,"shown in the NRC staff's safety evaluation for the topical rcport, lists the mean time bctwccn failures (MTBF)for St. Lucic Unit 2 as 108 months.
The MTBFwas calculated by dividing thc number ofplant operating years by the number ofESFAS subgroup relay failures, then converting the result into months. FPL has reviewed relay failure data from the Nuclear Plant ReliabilityData System (NPRDS) and has confirmed that onc additional relay failure occurred at PSL2 subsequent to the data collection phase ofthc CE study. This failure occurred on January 14, 1993, and results in a revised MTBFof 84 months.
To support a surveillance interval extension to once per 18 months (refueling cycle), the MTBF should bc greater than 22.5 montlis (18 month interval plus 25% tolerance permitted by TS). The plant-specific data morc than satisfies this criterion.
FPL has confirmed that thc relay data presented in CEN-403, Revision I-A, is applicable to St. Lucie Unit 2; however, two minor discrcpancics are noted in the information contained in the report: (1) the report states that St. LucicUnit 1 and Unit 2 each have about 200 relays whereas thc correct number is approximately 100 relays per unit; and (2) the rcport states that St. Lucie uses Couch model KEN 431A part number 4CP AF relays which is an over-simplification of the specific make and model numbers used.
The error in the number of relays installed in thc unit is not significant because it has no effect on the calculated MTBF, a critical attribute used in the NRC staff evaluation to support the conclusion that the reliability (small number of failures) justifies extending the surveillance intervals.
Thc relay make and model over-simplification is a reporting detail only (KEN431A is a supplier part number and not a relay model number), and docs not affect the conclusions ofthc rcport since thc failure history and data cvaluatcd in the rcport is associated with the relays currently in use at PSL2. As such, CEN-403, Revision 1-A, remains applicablc to St. Lucic Unit 2.
In addition to confirming CEN-403, Revision 1-A, applicability to PSL2, the staff's safety evaluation for thc topical rcport states that thc liccnscc should confirm that applicable sctpoint calculations account for any increase in instrument driR caused by the extended test interval. Since the subgroup relays are part ofthe actuation logic downstream of the ESFAS trip bistablcs, setpoint uncertainty calculations are not affecte by thc proposed surveillance interval extension, i.c., in the ESFAS design configuration and modes ofoperation, thc subgroup relays arc not subject to time-rclatcd instrument drilt. However, sctpoint calculations are applicable to thc
St. Lucie Unit 2 Docket No. 50-389 Proposed Liccnsc Amendment ESFAS Sub ou Rela Surveillance L-97-191 Page4of 4
ESFAS bistables which willcontinue to be tested at the prcscntly rcquircd monthly sur vcillancc frequency. The TS change proposed for this amcndmcnt only applies to thc semi-annual surveillance testing presently required for the subgroup relays.
Consistent with thc staK's position regarding two or morc ESFAS subgroup relay failures in a 12-month period (stated in the safety evaluation for CEN-403, Revision 1-A), thc proposed TS Bases revision states that the design, maintenance, and testing ofall ESFAS subgroup relays should bc considcrcd to cvaluatc the adequacy ofthe survcillancc interval. Ifit is determined that the survcillancc interval is inadequate for detecting a single relay failure, the surveillance interval should be decreased such that FPL can dctcct an ESFAS subgroup relay failure prior to occurrence of a second failure. In addition to the Bases statements, plant procedures willbe rcviscd to reflec this provision upon implementation ofan amcndmcnt incorporating the proposed surveillance interval cxtcnsion.
Conclusion Thc proposed surveillance interval extension for the St. Lucie Unit 2 ESFAS subgroup relays is consistent with the rccommcndations ofthe CEOG and NUREG-1366. CEN-403, Revision 1-A is applicable to PSL2, and this request forTS change using that topical rcport as a basis conforms to thc conditions specified in thc NRC stafFs acccptancc letter and associated safety evaluation for that rcport.
I St. Lucic Unit 2 Docket No. 50-389 Proposed Liccnsc Amendmcnt ESFAS Sub ou Rcla Surveillance L-97-191 ATTACHMENT2 DETERMINATIONOF NO SIGNIFICANTHAZARDS CONSIDERATION
a
St. Lucic Unit 2 Docket No. 50-389 Proposed License Amendment ESFAS Sub ou Rela Survcillancc L-97-191 Pagel of 2 DETERMINATIONOF NO SIGNIFICANTHAZARDS CONSIDERATION Description ofamendment request:
The proposed amcndmcnt willextend thc semi-annual surveillance interval specified in Table 4.3-2 for testing the Enginccred Safety Features Actuation System (ESFAS) subgroup relays to an interval consistent with Combustion Enginccring Owners Group Rcport CEN-403, Revision 1-A, March, 1996, and its associated Safety Evaluation which was issued by thc NRC staK on February 27, 1996.
Thc proposed surveillance interval is at least once pcr 18 months, with testing to be performed on a staggered test basis.
Pursuant to 10CFR50.92, a dctcrmination may bc made that a proposed liccnsc amcndmcnt involves no significant hazards consideration ifoperation ofthc facilityin accordance with thc proposed amcndmcnt would not: (1) involve a significant incrcasc in thc probability or conscqucnccs ofan accident previously evaluated; or (2) create thc possibility of a ncw or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin ofsafety.
Each standard is discussed as follows:
(1) Operation ofthe facilityin accordance with the proposed amendment would not involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed amendment rcviscs thc testing frcqucncy ofESFAS subgroup relays, and is based on demonstrated relay reliability. These relays actuate thc cnginecrcd safety features (ESF) cquipmcnt which is installed to mitigate design basis accidents.
ESF system components are not considcrcd initiators of any design basis accident.
Thcrcfore, operation of thc facility with thc proposed amcndmcnt would not involve a significant increase in thc probability ofan accident previously cvaluatcd.
The proposed amendmcnt does not alter the design or operation ofESF systems.
The mean time bctwecn failures demonstrated by the ESFAS subgroup relays is significantly grcatcr than the proposed survcillancc interval, and testing willbe pcrformcd on a staggcrcd test basis.
This, in addition to ESF redundancy, provides assurance that these systems willcontinue to function as cvaluatcd to mitigate design basis accidents.
Thcrcforc, operation of the facility in accordance with the proposed amendmcnt would not involve a significant increase in the conscqucnccs ofan accident previously cvaluatcd.
(2) Operation ofthe facilityin accordance with the proposed amendment would not create the possibility ofa new or different kind ofaccident from any accident previously evaluated, The proposed amendmcnt willnot change thc physical plant or thc modes ofoperation defined in thc facility liccnsc. Thc changes do not involve thc addition ofnew cquipmcnt or thc modification ofexisting equipment, nor do they alter thc design ofSt. Lucic plant systems.
Thercforc, operation ofthc facilityin accordance with the proposed amcndmcnt would not crcatc the possibility of a new or diffcrcntkind ofaccident from any accident previously evaluated.
St. Lucie Unit 2 Docket No. 50-389 Proposed License Amendment ESFAS Sub ou Rcla Surveillance I 97-191 Page2of 2
(3) Operation ofthe facilityin accordance with the proposed amendment would not involve a significant reduction in a margin ofsafety.
The proposed amendment revises the survcillancc interval for testing the ESFAS subgroup relays consistent with thc Combustion Engineering Owners Group topical rcport CEN-403, Revision 1-A, and conforms to criteria specified in thc associated safety evaluation issued by thc NRC staff. The St. Lucie Unit 2 subgroup relay mean time bctwccn failures is significantly grcatcr than thc proposed surveillance interval, and testing willbc performed on a staggcrcd test basis.
ESFAS setpoints, system operation, and plant configuration willnot bc changed, and the subgroup relays are not subject to time-related instrument drift. Accident analyses assumptions, initial conditions, and conclusions rcportcd in the Updated Final Safety Analysis Report are not changed by the revised survcillancc interval. Therefore, operation ofthe facilityin accordance with the proposed amcndmcnt would not involve a significant reduction in a margin ofsafety.
Based on thc discussion presented above and on the supporting Evaluation ofProposed TS Changes, FPL has concluded that this proposed license amcndmcnt involves no significant hazards consideration.