ML20011E761

Final Deficiency Rept CP-89-013 Re Potential for Asco Solenoids on MSIVs to Open After Initial Closure.Initially Reported on 890503.Valves Included in Equipment Qualification Program & Cautionary Tags Placed on Valves

ML20011E761
Person / Time
Site:	Comanche Peak
Issue date:	02/07/1990
From:	Woodlan D TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CP-89-013, CP-89-13, TXX-90013, NUDOCS 9002220398
Download: ML20011E761 (3)

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. . -- Log # TXX-90013 L

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File # 10110 907.3 Ref. # 10CFR50.55(e) nlELECTRIC i

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February 7, 1990 tuam vuswam s U.~S. Nuclear Regulatory Commission .

b Attn Document Control Desk .:

Washington, D.C. 20555 l

. 6

SUBJECT:

. COMANCHE-PEAK STEAM ELECTRIC STATION (CPSES)  :

l DOCKET NOS. 50-445 AND 50 446

'ASCO. SOLEN 0 IDS FOR MAIN STEAM ISOLATION VALVES SDAR: CP-89-013 (FINAL. REPORT) .)

Gentlemen:.

4 On May.3, 1989,'TU Electric: verbally notified the NRC of a potentially reportable deficiency involving the potential for the Main Steam Isolation -!

Valves (MSIV's) to reopen after initial closure. The latest. report on this issue. . logged TXX 89371; was submitted June 2,1989. After further evaluation -

it has.been concluded that this deficiency meets the criteria for reportability. pursuant to 10CFR50.55(e) and the required information follows. l

Description:

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~The MSIV.'s.are' hydraulically operated valves. When the MSIV's are in the open '

position, four Rockwell Solenoid valves (SOV's) in the hydraulic lines are

. closed (deenergized). ;This permits hydraulic fluid supplied from an air. ,

operated hydraulic pump to maintain the actuator in the.open position. . - An

• ASCO air ' supply ~ solenoid valve is deenergized-open to admit air to the hydraulic pump. When the MSIV's are required to close, the four Rockwell solenoids in the hydraulic lines are energized to open, dumping hydraulic. '

' fluid to'a reservoir and permitting-the actuator to reposition to the closed  ;

position. At the same. time, the ASCO SOV in the air supply to the hydraulic pump .is energized- to close to prevent the hydraulic pump f rom continuing.-to run. ,

C The MSIV; actuators for CPSES were purchased from Rockwell International. The TV Electric purchase specification reauired\ that the actuator hydraulic

. solenoids operate in a deenergized status when the MSIV's are open. This was y 'a departure from the design normally supplied by Rockwell (deenergize to close) and was specified to minimize the number of plant-trips and consequent challenges to plant safety systems that would occur if normally energized i solenoids were to fail at power and shut the HSIV's. The valve actuators were supplied as requested: however, as a result of this change, the generic equipment qualification testing performed by Rockwell was not directly applicable to CPSES. Rockwell provided an alternate qualification report justifying qualification by taking credit for the solenoids in the hydraulic

. lines,to initially energize open, thereby dumping the actuator hydraulic fluid

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. I TXX 90013 j February 7, 1990 j Page 2 of 3 j

and shutting the MSIV. To maintain the.MSIV shut for an extended period of i time after a high energy line break. Rockwell-recommended that credit be taken j for the ASCO solenoid in the air supply line to the hydraulic pump to  !

energizing shut and remaining shut for the duration of the event. l l

This was the approach stilized at CPSES to demonstrate qualification of the  ;

MSIV's. . Electrical Conductor Seal Assemblies were added to bring the solenoids into a qualified configuration. On January 7. 1988, a final report t was submitted on SDAR CP 84-12 " Impact of HELB Temperatures on Qualified i Equipment Outside Containment." indicating that applicable components, including the MSIV's, were qualified. l During performance of reconciliation activities associated with MSIV ,

qualification status it was identified that the MSIV's were not qualified f unless credit was taken for the ASCO solenoid which is powered from a non-IE power supply. Although this is technically acceptable (see FSAR 0140-1 and' ,

0010.20), the cables and junction boxes associated with the ASCO solenoid valves were not documented as qualified in accordance with programmatic controls at CPSES structured to maintain the status of qualified components.

In the absence of such controls it is possible that future activities may have ,

challenged the qualified status of the electrical components associated with the ASCO solenoid. i Safety Sianificance The MSIV's are relied upon to ensure that for an unisolable main steam line.

break outside containment, the non-faulted steam generators do not backfeed- ,

the break through the MSIV's. Failure of the MSIV's to remain shut following a break in this location could result in cooldown and positive reactivity addition to the primary plant.in excess of that analyzed and therefore could have been adverse to the safety of operation. As a result, this deficiency is considered reportable pursuant to 10CFR50.55(e). ,

Corrective Action TV Electric has included the ASCO solenoid valve in the Equipment Qualification Program, establishing the required supporting documentation.

• Because of its uniqueness, additional measures have been implemented to ensure the continued qualification of this component over the life of the plant. The. ,

measures include annotating the equipment list, and the instrument and control, and electrical drawings with a note specifying that the environmental qualification of the Train C solenoid valve must be maintained. In addition, 4

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i TXX-90013 j February 7, 1990 Page 3 of 3  ;

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. cautionary tags have been placed on the scienoid valves, Electrical Conductor Seal Assemblies, and junction boxes. Also the system's design basis document

. states that.these-solenoid valves must be maintained environmentally  ;

qualified. -

Sincerely, f

j. William J. Cahill, Jr.-

i i By: ,

D.- R. Woodlan ,

Docket Licensing Manager 4 JDR/grp c - Mr. R. D. Martin, Region IV Resident inspectors, CPSES (3)  ;

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