TXX-6992, Interim Deficiency Rept CP-87-28 Re Condensate Storage Tank Overpressurization.Initially Reported on 870629.Proposed Design Mod Under Evaluation.Schedule for Completion of Mod Will Be Provided in Suppl Rept by 880304

Interim Deficiency Rept CP-87-28 Re Condensate Storage Tank Overpressurization.Initially Reported on 870629.Proposed Design Mod Under Evaluation.Schedule for Completion of Mod Will Be Provided in Suppl Rept by 880304

ML20236W795
Person / Time
Site:	Comanche Peak
Issue date:	12/02/1987
From:	Counsil W, John Marshall TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
CP-87-28, TXX-6992, NUDOCS 8712080237
Download: ML20236W795 (2)

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Log # TXX-6992 Fiie # 10110 1

.= = 910.4 RIELECTRIC Ref.-#.10CFR50.55(e) wnuam c. counsa December 2, 1987 Lucuthe Vnv Pusident U. S. Nuclear Regulatory Commission

l. Attn: Document Control Desk Washington, D. C. 20555 SUBJEC1: COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NOS. 50-445 AND 50-446 CONDENSATE STORAGE TANK OVERPRESSURIZATION SDAR: CP-87-28 (INTERIM REPORT)

Gentlemen:

On June 29, 1987, we verbally notified your Mr. H. S. Phillips of a potentially reportable item involving the capacity of the condensato storage tank (CST). We have concluded this issue is reportable under the provisions of 10CFR50.55(e). Our last interim report was logged TXX-6724, dated September 11, 1987. The required information follows. ,

i DESCRIPTION OF DEFICIENCY I A pctential problem related to overpressurization of the CST has been '

identified. Specifically, the instrumentation and control of the CST allows l the tank to be completely filled (to 'the top of the tank) during normal . plant 1 operation. In case of a condenser ' surge to the CST, the overflow capacity of the CST would be insufficient ~to prevent overfilling / overpressureof the CST.

These conditions could cause rupture of the tank, jeopardizing the operation of the auxiliary feedwater system.

The design pressure of the CST is atmospheric. The design pressure of the CST can be exceeded by inadequate overfill protection which would cause the tank's water level to exceed the tank Design Water Level (DWL). During normal tank j makeup of 150 gpm, the current o/erflow design would prevent the CST from )

exceeding its DWL; however. during the maximum condenser surge flow of 1,500 j gpm, the current overflow cannot provide sufficient letdown to prevent )

overfilling / overpressure of the CST. This represents a significant. deficiency 1 in the final design as released for construction. >

l l The cause of this deficiency is the failure by the design organization to j provide adequate overfill protection for the CST. This condition affects only  !

the CST. i j

'87'12080237 871202

. DR. ADOCK'050 5  %'

o North olwe Street LB 81 ,oullas, Texas 73201 4k y .

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i TXX-6992 December 2, 1987 Page 2 of 2 SAFELY IMPLICATION Should the CST rupture due to overpressurization, it could adversely af fect the operation of the auxiliary feedwater system. The CST provides condensate to the auxiliary feed pumps during accident conditions. Therefore, had the identified condition remained uncorrected, it could have adversely affected the safety of operations of the plant.

CORRECTIVE ACTION We are currently evaluating a proposed design modification to install a safet)-related control feature for the CST level transmitters which will isolate CST makeup using redundant safety grade valves when the CST high level i setpoint is reached. The resulting additional inventory of condensate will be l allowed to accumulate in the condenser hotwell. '

We will provide a echedule for the completion c,f the modification in a i supplemental report which we expect to submit by March 4,1988. I Very truly yours, I

(). $. Cou n n l W. G...Counsil By: N

• d J. S. MarshaTi Supervisor, Generic Licensing MCP/grr  ;

c - Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3)