TXX-8876, Supplemental Deficiency Rept CP-85-12 Re Auxiliary Feedwater Pressure Control.Initially Reported on 850415.Safety-related Air Supply to Min Flow Recirculation Line Control Valve Added on to Each Motor Driven Auxiliary Feedwater Pump

Supplemental Deficiency Rept CP-85-12 Re Auxiliary Feedwater Pressure Control.Initially Reported on 850415.Safety-related Air Supply to Min Flow Recirculation Line Control Valve Added on to Each Motor Driven Auxiliary Feedwater Pump

ML20206D338
Person / Time
Site:	Comanche Peak
Issue date:	11/09/1988
From:	Counsil W, Woodlan D TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
CP-85-12, TXX-88762, NUDOCS 8811170048
Download: ML20206D338 (2)

Text

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=T Log # TXX-88762 5

Fi1e # 10110 909.3 Ref. # 10CFR50.55(e)

. 7t#ELECTRIO

, N'ovember 9, 1988 -

wm. c. cm a a 1.ttcuttw Yke President U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET N05. 50-445 AND 50-446

, AUXILIARY FEEDWATER PRESSURE CONTROL SDAR: CP-85-12.(SUPPLEMENTALREPORT)

. Gentlemen:

On April 15, :985, we notified you by our letter, logged TXX-4456. of a deficiency involving preliminary flow balance calculations that identified unacceptable setpoints for the auxiliary feedwater (AFW) system which we deemed reportable under the provisions of 10CFR50.55(e). This issue was subsequently identified by our report logged TXX-6435, dated May 13, 1987, as an item for which a final report had been issued. However, the originally scheduled completion date for the implementation of corrective actions has elapsed and the original corrective actions require revision and therefore have not been impleiranted. This report is submitted to revise the corrective actions, and update the status of corrective action implementation.

Description Preliminary flow calculations performed in early 1985 identified unacceatable

+ conditions apparently resulting from the setpoint of the AFW flow control valves. The original setpoint calculations assumed that all available AFW flow would be directed to the steam generators. However, if a minimum flow recirculation control valve (upstream of the AFW flow control valve) were to

-fail in the open position, the amount of flow actually reaching the steam generator would be approximately 17% less than required. This deficiency was

' reported to the NRC in TXF-4456 on April 15, 1985. The corrective action planned at that time was to perform hydraulic calculations and instrumentation calculations that would resu)t in revised setpoint and scaling documents, in addition, the flow control valves were to be recalibrated.

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TXX-88762 November 9, 1988 Page 2 of 2 In August of 1986, hydraulic calculations and a review of instrument accuracy requirements revealed that a setpoint change would not correct the deficiency.

The cause of the deficiency was that the design did not provide a safety-related air supply such that the minimum flow recirculation control valves would close to ensure that all available AFW flow would be directed to the steam generators.

The Corrective Action Program at CPSES validated the vital station drawings and verified the presence of air accumulators where needed to ensure performance of a safety function. No other deficiency was found where a necessary safety-related air supply was not provided.

Safety implications Had this deficiency remair.ed uncorrected, it could have adversely affected the safety of operations in that the steam generators may not have received sufficient AFW to operate within technical specification limits and FSAR commitments.

Corrective Action The revised corrective action for this issue is the addition of a safety-related air supply (from an existing safety-related accumulator) to the minimum flow recirculation line control valve on each motor driven AFW pump.

The Unit 1 estimated completion date for this activity is January 27, 1989.

The Unit 2 corrective action will be completed prior to the start of Unit 2 Hot Functional Testing (HFT).

Very truly yours, l.Nh. kU W. G. Counsil By: b 0710. Wo6dlan Docket Licensing Manager CBC/mlh c-Mr. R. O. Martin, Region IV Rc%ident inspectors, CPSES (3)