ML20205H073

Responds to IE Bulletin 85-003, Motor-Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings, Per 851115 Request.Valves Meet Requirements for All Pressure Levels

ML20205H073
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	05/14/1986
From:	Murphy W VERMONT YANKEE NUCLEAR POWER CORP.
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
FVY-86-45, IEB-85-003, IEB-85-3, NUDOCS 8608190715
Download: ML20205H073 (4)

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Q VERMONT YANKEE NUCLEAR POWER CORPORATION FVY 86-45 RD 5. Box 169. Fctry Road. Brattleboro. VT 05301 g

ENGINEERING OFFICE N

1671 WORCESTER RO AD FR AMINGHAM. MASS ACHUSETTS 0 t ?01 7Esf 8+CNE 4 t'J Ma May 14, 1986 U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Attn:

Mr. Thomas E. Murley Regional Administrator

References:

a)

License No. DPR-28 (Docket No. 50-271) b)

Letter, USNRC to All Holders of Nuclear Power Reactor Operating Licenses (OL's) or Construction Permits (CP's) for Action, NVY 85-250, dated November 15, 1985 (IE Bulletin No. 85-03)

Subject:

Vermont Yankee Response to NRC IE Bulletin No. 85-03:

" Motor Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings" By letter dated November 15, 1985 (Reference b)], the NRC's Office of Inspection and Enforcement requested licensees to develop and implement a program to ensure that switch settings on certain safety-related motor-operated valves are selected, set, and raintained correctly to accommodate the maximum differential pressures espected in these valves during both normal and abnormal events within the design' td: sis.. In accordance with the requirements set forth in the subject Bulletin, Vermont Yankee herein reports the results to date of our review and documentation of the design basis for the operation of each motor-operated valve in the High Pressure Coolant Injection (HPCI) and Reactor Core Isolation Cooling (RCIC) systems that are required to be tested for opera-tional readiness in accordance with 10CFR50.55a(g). Additionally, we are pro-viding a discussion of our program to ensure that valve operator switches are selected, set and maintained properly, including a proposed schedule for comple-tion of these items.

Vermont Yankee's preliminary review of the design basis for the operation of each valve indicates that the design basis HPCI and RCIC valve' differential pressures, as specified in the original plant documentation, are equal to or greater than the differential pressures they could be subjected to during nor-mal, abnormal, and accident conditions where their positioning or repositioning 1

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VEIO10NT YANKEE NucLEAn PowEn ConconATioN U.S. Nuclear Regulatory Commission May 14, 1986 Page 2 l

is relied upon. This also includes inadvertent valve closures and openings.

Table 1 (attached) provides an itemized list of all valves within the scope of Bulletin 85-03 and their design differential pressures. We are presently docu-menting, by calculation, the normal, abnormal, and accident scenarios and pressures that could be applied to each valve.

This will form part of the final submittal described below and will ensure that all scenarios were reviewed.

Vermont Yankee's program to ensure that valve operator switches are selected, set, and maintained properly is a four-fold program.

First, the required stem thrust for each valve will be calculated based on its highest dif-ferential pressure.

Second, the Motor Operated Valve Analysis and Test System

("MOVATS"), or a similar program will be applied to diagnose the valve's charac-teristics, and set the motor operator to produce the calculated stem thrust.

Motor-operated valve limit switch settings will be controlled by approved plant procedures.

Third, the maintenance program will be enhanced to review each motor operator and ensure correct and undamaged parts. Finally, Vermont Yankee has an ongoing preventive maintenance program to ensure correct switch settings are maintained. Given the past history of motor operators, Vermont Yankee believes this is the best way to insure their represented capabilities are available.

"MOVATS" was evaluated in NUREG/CR-4380 by the Oak Ridge National Laboratory and found to " provide valuable diagnostic information regarding the operational readiness of MOV's well beyond that obtainable from ASME Code Section XI type surveillance tests." Because of these diagnostic capabilities, it can be used to properly adjust motor operators to achieve their design capa-

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bilities. Procedures for operating the "MOVATS" equipment are available et pre-sent and an overall Vermont Yankee procedure will be written to reference stem thrust calculational data, the MOVAT's procedures and the limit switch settings as shown on the control wiring diagrams.

Full design differential pressure (DP) testing at Vermont Yankee is not viable. However, we are, currently considering a test using normal operating differential pressure. The required stem thrust for this OP would be calculated for the selected valve (s), the torque switch reset to reflect that thrust, and then the valve would be operated.

This should show generically that the VY program of setting torque switches to a calculated stem thrust, based on maximum OP, will be acceptable.

. ' gf We plan to complete the program outlined above as soon as practical, but no l ( I I ')

later than the end of our scheduled 1988 (Cycle 14) refueling outage. Within 60 l

days of completion of the program, we will subrit a written report providing verification of completion of the requested program; a summary of the findings as to valve operability prior to any adjustments resulting from the Bulletin; and a summary of data in accordance with the Bulletin's suggested data summary report.

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VlinMONT YANKEft NUCt.t!An Powl!It Cont >olt ATioN U.S. Nuclear Regulatory Commission May 14, 1986 Page 3 We are aware of t e BWR Owner's Group (BWROG) initiative to respond to this h

IE Bulletin, and plan to monitor the Owner's Group activities, however, we wish to keep the option of endorsing the final, accepted position.on this issue open.

Any such endorsement would be made in our written report, provided in accordance with the schedule provided above.

We trust that the information provided above is' responsive to the require-ments of the subject Bulletin; however, should you have any questions or require additional information, please contact us.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION 4e o un Warren P., urphy Vice President and Manager of Operations

/dm STATE OF VERMONT)

)ss WINDHAM COUNTY )

Then personally appeared before me, Warren P. Murphy, who, being duly sworn, did state that he is Vice President and Manager of Operations of Vermont Yankee Nuclear Power Corporation, that he is duly authorized to execute and file the foregoing document in the name and on the behalf of Vermont Yankee Nuclear Power Corporation and tha,t the statements therein are true to the best of his knowledge and belief.

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Diane M. McCue

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ey TABLE 1-DESIGN DIFFERENTIAL HPCI

__ PRESSURE (psi)

PV23-14 Steam to Turbine 1250 V23-15 Steam Supply Isolation 1250 V23-16 Steam Supply Isolation 1250 V23-17 Condensate Storage Tank Pump Suction 100 V23-19 Pump Discharge 1250 V23-20 Pump Discharge 1250 V23-21 Test By-Pass 1250 V23-24 Test By-Pass 1250 V23-25 Minimus Flow By-Pass 1250 V23-57 Pump Suction from Suppression Chamber 150 V23-58 Pump Suction from Suppression Chamber 150 RCIC V13-1 Trip Throttle Valve 1350*

V13-15 Steam Supply Isolation 1250 V13-16 Steam Supply Isolation 1250 V13-18 Condensate Storage Tank Pump Suction 150 V13-20 Pump Discharge 1500 V13-21 Pump Discharge 1500 V13-27 Minimus Flow By-Pass 1500

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V13-30 Test By-Pass 1500 V13-39 Pump Suction from Suppression Chamber 150 V13-41 Pump Suction from Suppression Chamber 150 V13-131 Steam to Turbine 1250 V13-132 Lube Oil Cooler Water Supply 1500

• Seat Closure Test with Operator

,