ML20069K371

Forwards Supplemental Info to Provide Clarification for Questions Remaining from 940407 Conference Call Re GL 89-10 Closure Document

ML20069K371
Person / Time
Site:	Callaway
Issue date:	04/15/1994
From:	Reidmeyer M UNION ELECTRIC CO.
To:	Thomas Scarbrough NRC
References
GL-89-10, NUDOCS 9406160066
Download: ML20069K371 (9)

Text

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AFF 15 '94 01:24At1 U E. CALLMn FuAi4T P,2 Cuo.,o err p:n :" e Eu no

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U.S. Nuclear Regulatory Commission Mr. Thomas Scarbrough Mail Stop 7E23 OWFN Washington, DC 20555-0001 Fax: 301-504-3861 Enclosed is supplementalinformation to provide clarification for questions remaining from the April 7,1994 conference call regarding Callaway's GL 89-10 closure documem 1)

Additional information on check valve back leakage. Reference Question No. 3.

2)

AdditionalInformation on linear extrapolation. Reference Question No. 7.

3)

Additionalinformation on butter 0y valve margin. Reference Question No.12.

This information is being sent to you to facilitate fbrther discussion the week of April 18,1994.

Please contact me if you need additionalinformation.

A Mark Reidmeyer QA Engineer 314-676-4306 i

MAR /tmw Enclosures l

cc: NRCI 94002 S. H. Reed, UENE MOV Engineer I

314-676 8540 D. E. Shafer, UE Licensing 1iN

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U.S Nuclear Regulatory ConurJssion l

RegionIII Attn: Marc Huber 801 Warrenville Road Ide,IL 60532-4351 Fax: 708 515-1249 Enclosed is supplementalinformation to provide clarification for questions remainmg from the April 7,1994 conference call regarding Callaway's GL 89-10 closure document 1)

Additional information on check vah e back leakage. Referenc: Question No. 3, 2)

AdditionalInformation on linear extrapolation. Reference Question No. 7.

3)

Additionalinformation on butterfly valve margin Reference Question No.12.

This information is being sent to you to facilitate fbrther discussion the week of April 18,1994 Please contact me if you need additional information.

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-!r MarkReidmeyer i

QAEngmoer 314-675-4306 i

MAR /tmw Enclosures cc: NRCI 94002 S. IL Reed, UENE MOV Engineer 314-676-8540 D. E. Shafer, UE Licensing

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JeR 15 '54 01: 2%'1 U. E. CALLM r PLmT Fa ADDmONAL INFORMATIQN ON CHECK VALVE BACKLEAKAGE Question 3 The licenses states that credit is taken for operator identification of check valve backleakage. To what extent is much credit taken in determining the design-basis differential pressure for GL 09-10 MOVs?

Concluelon The generic analysis performed by Westinghouse assumed check valve leakage for a tctal of 22 valves. Due te Callaway specific design and l

piocedures, the generic operating scenarios are not applicable for 17 of the 22 valves. The 5 valves that the generic study is applicable to requires valve :.ispositioning in addition to the check valve leakage, callaway monitors pressure 3 tir.as a day in these lines.

If increasing pressure is identified, corrective actions will be impler.ented.

KQVS WHICH WESTINQHQUSE ASSUMED 85ACKLEAKAGE RHR SYSTEM E!-HV-Sella & B CTMT RECIRC SUMP TO BHR PMP EJ-HV-8809A & B RHR ACC INJ SUPPLY ISO EC-HV-8840 RHR SI SYS HO! LEG RECIRC ISC E!-HV-8804A & B RHR TO CHG AND SI PUMPS ISO EJ-HV-8'116A & E RER HOT LEG RECIRO !$O EN-HV-8812A & B RWST TO RHR PMF ISO EJ-r V-0E10/611 RHR MINITLOW RE0IRC 1

81 SYSTEM EM-HV-8835 SI TMP TO CL INJ I5C EM-HV-8821A & B SI PMP TO CL INJ !$O I

EM-HV-8923A & B RWST TO SI PMP ISO ACCUMULATORS EF-HV-88CBA,B,C,D SI ACC TK OUTLET ISO VLV

AF: 15 *34 C1:ifAn L.E. CALLAWAY PLAbT' p,5 l

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DISCUSSION The above list represents the valves which Westinghouse in their generic study WCAP 13097, ' SYSTEM QPERATING BASIS FOR MCTOR OPERATED VALVES', assumed back leakage from the RCS via check valves. Assundng this leakage resulted in a higher design differential pressure than other design conditi:ns. The leakage was assumed to cecur over a period of time such that it was within allowable limits, and was not considered 1

a failure. Using the RCS as a pressure source due to this leakage was l

considered for the initial valve operation but, due to its slow nature, l

not in subsequent valve movement. In many cases, the subject valve was i

censidered to be mispositioned coincident with the check valve leakage.

The above valves will be separated into two categories. The first group of valves will be M3Vs for which Callaway specific design randers the Westinghouse assvned operating condition net applicable to Callaway.

The secend group are MOVs that Callaway takes credit for identifying the 1eakage and implementing ad.inistrative controls to ensure it is not a pressure source for the valve differential pressure.

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see TSAR Section 5.2 for additional discussion.

Group 1, Westinghouse Study Not Applicable Due To Callaway Specific DWeign Aru$ Procedures EJ-KV-SB09A & B, EM-NV-8935, EP-HV-SEOGA, B,C,D These seven valves are all normally open with power removed. The Westinghouse scenario assumes in addition to the back3 eakage that they art either nuspositiened closed, or they must open en receipt of a SI signal. With pcwer removed this is'not a credible scenario.

EJ-HV-2715A 6 B, EP.-KV-8 923A These three valves are norrally open with "Stop and Think" covers to prevent mispositioning. They are identified in standing order 93-001R1 as T/S 3.0.3 valves, raaning if they are c1csed the plant must 1-mediately enter Technical Specification 3.0.3, and commence a plant shutdown.

Based en this, it is not a crecible scenario at Ca11 sway for these valves to be nispositioned for any length of time,.such that they would be required to re-cpen with a high differential pressure from check valve leakage.

EJ-TCV-0610 s C611 These RHR minificw isolation valves are normally open. Callaway's plant alignment is such that if they were mispositoned and check valve leakage occurred, both the upstream and downstream side of the valve would be subject to the same pressure (i.e. no DP created).

j EJ-HV-9811A & B These are the normally closed CTMT recirculation sump to the RHR i

pump isolation valves. The generic Westinghouse study assumed check valve leakage and then these two MOVs opening en receipt of a SI signal.

i At Callaway, these valves do not stroke open until the RMST has been depleted. At this point the RER purps have been running for some time i

and check valve leakage is not applicable.

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APR 15 '94 01:26At1 U.E. CALL Wty PLftiT P.6 EJ-HV-88C(A & B These are the nornally closed RHR to the CCPS and S! purps isolation valves.

Similar to EJ-HV-6811, these valves open after the B'AST has been depleted during the swap over to the CTMT recirculation sa=p.

Again, the RHR pumps would have been running for some time, therefore check valve leakage is not applicable.

(Note, for both 8811 and 8804, increasing pressure would be identified by the shittly checka done en the RHR discharge pressure indicator prior to use of the MOV.)

EJ-HV-8840 This valve is the RHR system het leg recirculation isolation valve. During normal operation it is closed with power removed. The Westinghouse generic study described a scenario in which this valve is to be opened to start hot leg recirculation with the RCS pressure at 1200 psi. This is not a credible scenario at callaway. Not leg recirculation at callaway is implerented 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br /> after initiation of an accident. If for some reason RCS pressure is at 1200 pai, the RER pumps would have been stepped long before, since they are not capable of injecting at this pressure. This valve would not be opened until RCS pressure is low enough fer the RHR system to inject.

Group 2. Westinghouse Study Applicable, Adninistrative Controls Used BN-NV-8812A & B These are the normally open RWST to RHR puny isolation valve.

Ter the Westinghouse generic analysis, the valve would need to be miepositioned closed, and then have check valve leakage through 4 valves BBB948, EP8818, EJ6730, and EJB958. Hcwever, if the above conditions were to occur, increasing pressure would be identified by the shiftly check of RHR pump discharge pressure indicator, EJ-FI-614 (615). See the attached sheet from Callaway's Control Room logs, EM-HV-8021A & B These are the normally open SI pump to the BCS cold leg injection isolation valves.

Tor the Westinghouse generic analysis, the valve would need to be mispositioned closed, and then have leakage throagh check valves Bae948 and EPC010. However, if the above conditions were to occur, ir.eressing pressure wculd be identified by the shiftly check of the SI pc=p discharge pressure indicator EM-PI-0919(923).

EM-NV-8923B This in the normally open RNST to the SI pump B isolation valve.

Due to Callaway specific line-up, its counterpart on the A train is a T/s 3.0.3 valve, and has controls to prevent mispositioning, for the i

Westinghouse generic analysis, the valve would need to be miopositioned j

clssed, and then have leakage through check valves BB8948, EP8818 and i

EM8922B. Howaver, if the above conditions were to occur, increasing l

pressure would be identified by the shiftly check of the Si pung discharge pressure indicator EM-PI-0923.

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APR 15 '94 01:27AM U.E. CALLf441Y PLit4T p,7 Example Action N Leakage is identified This is one action that could be istplemented for all 5 of the above valves. However, the actual specific actions will be deterrr.ir.ed by the system engineer based on the plant conditions at the time the leakage is identified. The identification point for the pressure indicators were selected in order to allow time for actions to be taken.

One action could be to open the normally closed 3: test line.

This line is used for the periodic surveillance teccing of the purps.

Its flow can be routed to the RNST or the Recycle Hold-up Tank. A flow raster could be installed to verify that the check valve leakage remains within allowable limits.

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APR 15 '94 01:2741 U.E. CALL 4AY PL4R p,g UN10N ELECTRTC COMPANY ODP.ZZ.00016 CAL 1AWAY NUCLEAA_1J.AblI Rev 30

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1 20 i l MILE l (1) If Conditions permit while at full power. The pump controller in auto should be rotated Saturday FM shift.

(2) Speed is set to 3850 RPM by strobe. TACH per 0$P.AL.P0002.

(3) This light is indication of Turbine EHC control problems. The light should be verified to be extinguished. If this light is on, check EHC control canal AC119 for the cause of the ureblem.

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1 1847f5) 840 1 Ft. ME (4) Refer to APA.ZZ 01003 Section 9.1 for possible restrictions if this meter is out of service.

(5) Por Consistant Chemistry control of the Cooling Tower Basin. Level should be maintained between 245' and 846'. One foot of free board should be maintained durina norral Onaratinn Conditions.

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These instruments have been identified as indicators of back leakage. When the associt.ted pumps are idle, ensure pressure does not increase above the listed pressure. If action is required to prevent pressure build up above these limits, notify the system engineer.

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Fage 2 of 5 ATTACHMENT 1 1

FFR 15 '94 01:29Pr1 U.E. CALLAWAY PLAT p,9 ADDITIONAL INFORMATION ON LINEAR EXTRAPOLATION

SUBJECT:

QUESTION #7 "HOW IS LINEAR EXTRAPOI.ATION OF TEST DATA NSTIFIED?" This mfonnation is being provided in addition the discussion provuled on pages 4-1 through 4-3 of Callaway's closure de i

CONCLUSION:

The use of extrapolation methods to determine MOV thrust requirements at design basis condmons is supported by the recem testing perfonned by EPRI. De resuhs of EPRI's tesung showed that i

disc slidmg friction coefBeients tend to decrease at higher DP values. Thus, the linear edrapolation methodology has been shun to be conservative. Muhi-point DP testag g.fv.v d at Farley and Grand Gulf nuclear plamr also support this conclusion.

DISCUSSION:

EPRI has gife64 DP tesung of gate valves under urying condruans. low pressure cold water pumped Bow, intermediate pressure pumped flow, high pressure cold / hot water, and high pressure cold water and steam A summary of the test data has been provided on pages 10 -15 of to RFR 87461. De data shows for all test conditions that the disc shdmg friction coef5cient (k) decreases as the DP is inertased from a lower DP to lugbst DPl. This reduccan in disc friction at lugher DPs means that test data taken at lower DPs and extrapointed up will conservatively deternune the required thrust to operate at design DP. Thus the extrapolanon methodology is conservative.

The multi point DP testmg gifwird at Farley Nuclear Plant supports linear extrapolation of DP data. The graphs made from the linear regression analysis show that Farley's DP data can be accurately modeled using 1mear extrapolation in all cases, the small amount of data scatter from the line of best fh is within the measurement accuracy of the test equipment.

Grand Gulf has performed several DP tests at muhiple pressures. Their results also support linear extrapolation. MOV engmeers at Orand Gulf have used their DP data to compare various curve ft techmques including linear, ewW logarithmic, and peer. This companson shows knear regression to be the most appropriate method fbr modeling ulve thrust requiranents over a range of DP conditions.

Callaway's limitations on the use ofimcar extrapolation are given on page 4-1 of the Callaway closure document

! It should bc noted that the Huntsville low DP cold mater tosung (see page 11 of Att. 8 to RFR f

8746 I) was done before the need for pW= log was determmed Therefbre, the rise in disc p from low to high DP can be attributed to the preconditioning done on the high DP tests.

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ffR h5 A94 01:2Br,M U.E. CALLM5 PLfdT.

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.. s ADDITIONAL INFORMATION ON BUTTNLY VALVE MARCLN

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l Questfos 12 What margin is apphod to butter 6y MOVs for peno&c ven5 canon?

What is justi$ cation for static margin for bunerfly MOVs?

Conclusion j

lt is Callaway's intant to handle butter 6y MOVs in the same manner as risms stem MOVs.

We have DP tested 38 of the 40 valvos and set them up in accordance with these test resuhs 32 of the valves have more than 25% additional maram Action is planned for the rumamms valves, which includes re-DP tesang, torque swnch a4ustmem and spring pack replacommt Trundmg of MOV performance, feedback of butterfly re-DP test resuha and m- ;='= tion of relevant industry issues that may arise will idennfy any correenvc actions that need to be implemesed Discussion Actual DP test torque data has boem used to set up the butterfly MOVs Of the Ave valves which were set up using groupas, three have been DP testad, but at diffemanal pressures below i

the programmane level allowns use of the test data wahout fbrther analysis and justi$ cation.

Orouping with similar valves was annaimann with GL 8910 Supplement 6.

Use of the DP test approach avoids aliance on required torque values that have been calculated from assumed industry paramotors. Thorsfare, should an industry issue be con $nned rosarding onlculated prabetad torque values being lower than those actually found through testag.

Callaway's butterfly MOVs will not be adversely affecssd Seeing up to most the.l- -. Test Acosplance Cntena gg4 des a measure of margin to allow for possible valve detsnorsuon ( i.e. increased torque requusments) during the period befbre the next sost. The inborset margm in the minanum Test Acceptance Critena resuhs frtan numerous conservansms used in the a4ustment for test equipment enor, c=g= repostability and selection of" worst case" data poets Beyond the aforer===haamd inherent margm, all of the butterfly valves haw addiuonal maram above the. -

... Test Acceptance Critana, in fhet,32 of ths MOVs have an additional margin of more than 25%. Ahhough thste is no fonnal commensat inr =Meianal marsm, actions are planned for the ruinaining naht banerfly MOVs. Two valves are scheduled ihr reDP testag A4iustment of torque switch settings and replacenant of spnas packs, where approprises, are planned toinorcase addmanal marga Trundas programs at Callsway pumde for monnonas r.L a infbanstion on all GL 89-10 valves every 18 montha and Seedag this trend data back into the progrunn Air analysis, l

testag and set up of the MOVs. Trendag of this data for buncr6y valves provides udbanation necessary to detect valve portsmanne degradation, i.e. "asms", so that conootiw actions een be implemented if nocessary. Programs for moutonns mdustry evens and issues and appropriately foodmg this informanon back into the program are in place. Rasults of the rupesta1 butterfly DP tests wdl be analyasd and fed back into the program IDeta based on 4 1/2 year penodic tsaring done on a massered basis.

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