ML20059G175

Provides Results of Util Reevaluation of Response to NRC Bulletin 85-003.Util Believes That Previous Testing Results & Subsequent Submittals Provide Assurance of Continued Operability of Sys motor-operated Valves

ML20059G175
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	08/31/1990
From:	Chrzanowski R COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-85-003, IEB-85-3, NUDOCS 9009120178
Download: ML20059G175 (4)

Text

r Commonw3alth Edison

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r Downers Grove, Illinois 60515 August, 31. 1990 Mr. A. Bert Davis Regional Administrator U.S. Nuclear Regulatory Commission Region III-799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

Zion Station-Unit-1 & 2 Motcc Operated Valves IEB_d5-03 Subalttal NRC Docket Nos. 50-295/304

References:

(a)- NRC Confirmatory Action Letter'RIII 90-011',

dated June 22, 1990, regarding MOV Unit Switch o

Settings ~

(b) Commonwealth Edison Response to Items a-d of NRC Confirmatory Action LetteriRIII 90-011 dated June 25, 1990.

(c) Commonwealth Edison Response to-Items d,e of NRC Confirmatory Action Letter RIII 90-011 dated July 6, 1990.

(d) Connonwealth Edison IEB 85-03 Submittal Response,.

dated May 15,-1986.

(e) Commonwealth Edison Revised Response to NRC Request for additional information to NRC IE Bulletin 85-03, dated May 18, 1988.

Dear Mr. Davis,

i Referenced letter (a), NRC Confirmatory Action Letter RIII 90-011, required Commonwealth Edison to respond to various items concerning Motor.

Operated Valve Torque Switc'h Settings.

References (b) and-(c) transmitted.

Commonwealth Edison's responses to items a-e,of the Confirmatory Action-Letter.

The purpose of this letter is to-provide the results of Commonwealth Edison's re-evaluarton of Zion Station'st IEB-85-03 submittal (references (d) and (e)). 'This re-evaluation focused on the criteria used in selection of IEB 85-03 MOV population, the calculations and assumptions used in obtaining.

calculated maximum accident differential pressures:(DP), and-testing methods _

used.

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Q si Hith regards1to the MOV population selection,-Commonwealth Edison believes thatLit has included the proper valves.in the IEB 85-03: systems:(High. Pressure.-

Coolant Injection and Auxiliary feedwater)=-that;are required to'be tested for operational readiness in accordance with;.10.CFR 50.55 a(g).. Justification for-

-the exclusion:of: specific MOV's has been previously'transnitted to the NRC in of reference (e).

During the NRC RegionLIII D.E.T. follow-up

-Inspection #50-295/90014; 50-304/90016, the inclusion;of'several SVAG-(Spurious Valve Actuation Guideline) MOV's had been questioned.s These MOV's -

SI 8802 and SI 8806 (Common Safety Injection = Pump RHST Isolation and COLD Leg-Discharge Isolation) - are normally de-energtred open and.are stroke tested on-l a refueling /18 month basis per Technical ~ Specifications 4.8.2.A.3.and 4.4.2.

Zion Station will continue to considerJthese valves as bu11etin 85-03 MOV's.

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'This will ensure that they would be capable'of-performing their1 intended i

safeguards-function in the unlikely event of a Safety.. Injection Actuation b

during stroke testing of SI-8802 and/or SI-8806. -In addition, Zion Station-i has. reviewed a' proposed 1isting of MOV's to be added-to the IST Program and determined that none of these valves need to be. included as.IEB 85-03 valves.

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Commonwealth Edtson has reviewed the calculations and assumptions,used ir,-

formulating the accident maximum differential pressures for IE8 85-03 valves.

These values envelope all necessary valve operations duringeboth normal events and abnormal Design Basis events (LOCA, SGTR or Steam Break).L;The results of.

this review indicate that the values previously transmitted to the NRC in reference (e) are correct with the exception'of.the calculated maximum.

accident differential pressures for the Auxillary Feedwater (AFH)' Service Hater (SH) Suction H0V's and the AFN: Discharge M0V's.

The calculated-differential pressures should be changed to the1 corrected values as specified below:

TEST DP

-PREVIOUS CORRECTED j

U1/U2 CALC. DP CALC.-DP MOV ID.

DESIGN BASISJUNCTION (nsio)

(osia)

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MOV-SH0101 AFH Pp Suction Isolation 115/100 115 128 MOV-SH0102 from SH, normally closed 161/165 115:

128 MOV-SH0103 Manually opened upon low "115/100 115 128 H0V-SH0104 pump suction pressure 158/165-

115 131; H0V-SH0105 158/165 115-128-H0V-FH0050 AFH Discharge Isolation 1632/1550 1662* 1619 1619 MOV-FH0051 normally open, required

.1627/1550 1662* 1619 1619 HOV-FH0052 closed during SGTR and

-1615/1550 1669* 1626 1626 MOV-FH0053 S/G depressurization/

1625/1550 1669* 1626 1626-H0V-FH0054 steam-line break 1620/1550 1672* 1629 1629 MOV-FH0055 1615/1550L 1671* 1628 1628 HOV-FH0056 1615/1550 1663* 1620 1620 H0V-FH0057

'1617/1550 1663* 1620 1620

• DP expected while supplied with turbine driven pump.

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- The-AFH SH Suction MOV's-are manually opened by the operator After the~ AFHi

. pumps have been secured.per Procedure AOP 4.3 " Inadequate Auxiliary Feedwater-Supply".

In this condition, these MOV's would not be subjected to a.

! prolonged, high-flow differential pressure conditionLwhile stroking.

Since

.i the previous IEB 85-03 testing was performed at maximum obteh able differential-pressures, and'some of the values obtained were in' excess of the.

i corrected: maximum DP's (due to the use of demineralized' water system as pressure source where practical), no further differential pressure testing:Is necessary.

1 The accident scenario which generates the largest differential pressures; j

j for the AFH Discharge M0V's involves the depressurization of all four steam:

generators (caused by. multiple Main Steam-Isolation Valve failures);ln-conjunction with a steam line break..The scenario actually encompasses-thes worst case design basis accident,"and'is based on Zion's Emergency Operating Procedures.

The turbine-driven AFH pump would not even be available during this event.

The maximum calculated differential pressures are those associated with the motor-driven AFH Pump.

-It should be noted that the U1 TEST DP values for the AFH Discharge MOV's r

have been updated to reflect the latest differential pressure testing results.

These tests were performed per TSSP 239-89/TSSP 240-89 " Unit 1 Aux' i

FH MOV Spring-Pack Replacement Test".in December of 1989.-

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A review of the testing methodology and results obtained indicate that all

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of the IEB 85-03 valves were shown to be able'to perform their' design functions.

The test procedures stroked the MOV's against the maximum

.l obtainable differential pressures based on existing plant configurations.

In a

addition, the testing configurations attempted to-simulate pipe break conditions, where appropriate.

Further. discussion of testing methodology was

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previously transmitted to the NRC in references.(d) and (e).

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Corporate Nuclear Engineering Department (NED) is currently in the process et ~ calculating M0V thrust-" windows" - which are calculated using Limitorque 1

design data, valve 0.E.M. Information and differential' pressure testing results.

During future maintenance for those valves that_have VOTES sensors

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installed and thrust windows available, the torque switches will be set pers NED guidance (in accordance with Zion Station MOV Setpoint Control Proceduref ZAP 3-52-8).

For future maintenance on those IEB 85-03 valves tested'under-

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full differential pressure that are not able'to be tested with~ VOTES, their torque swltch settings will be conservativley based on'all available data (le:

IEB 85-03 stated values, Electrical Maintenance history, Limitorque design i,

data and valve OEM information) as concurred to by'NED, 9

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In summary, Commonwealth Edison believes.thatTthe previous'IEB 85-03 testing results and subsequent submittals'(references (d) and;(e)); coribined with improved MOV setpoint control: procedures, provide _ adequate assurance of f the-continued operability of.those Bulletin System Motor Operated Valves;which

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could be required to stroke against significant, differential pressures'during

-and/orcafter a design basis accident.

L If any questions-arise concerning-this matter, please! direct them.to this l

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office.

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Respectfully,.

'R.A. C anowski

. Nuclear. Licenr1ng Administrator i

cc: C. Patel - NRR Zion Resident Inspector NRC-Document Control Desk t

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