ML17272A868

Interim Deficiency Rept Re Condensate Collecting in Reactor Core Isolation Cooling Piping Due to Four Inch Steam Supply Piping to Turbine Coming Off Top of 10-inch Steam Supply Header Rather than Bottom.Drain Line Added

ML17272A868
Person / Time
Site:	Columbia
Issue date:	03/14/1980
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17146B321	List: ML17272A868
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8003240526
Download: ML17272A868 (1)

Text

Attachment 1 WPPSS NUCLEAR PROJECT N0.2 REPORTABLE DEFICIENCY AND CORRECTIVE ACTION FOR CONDENSATE IMPINGEMENT ON RCIC TURBINE WASHINGTON PUBLIC POWER SUPPLY SYSTEM DOCKET,NO. 50-397 LICENSE 'NO. CPPR-93 DESCRIPTION OF THE DEFICIENCY The four-inch steam supply piping to the Reactor Core Isolation Cooling turbine comes off the top of the 10" steam supply header, rather than the bottom. Therefore, condensate collecting in the 10" line has no way to drain to the drain trap at the low point of the four-inch line. The con-densate could form a water slug during RCIC turbine operation and damage the turbine or the steam supply pipina.

SAFETY IMPLICATIONS For all transients in which vessel level drops, initial core cooling is provided by either RCIC or HPCS (High Pressure Core Spray). However, RCIC is lost during an isolation transient due to this desiqn deficiency if and the single active component failure is HPCS, initial core cooling is no longer available. The operator would have to manually initiate the automatic depressurization system so that the low pressure core cooling systems can inject into the reactor. However, this scenario has not been evaluated in Chapter 15, so there is .no proof that the consequences are acceptable.

In addition, the water slug could damage the steam supply piping, which is part of the containment boundary. Loss of this piping just outside of the containment boundary plus the required single failure assumption of the inboard isolation, valve could provide a direct path from the reactor coolant pressure boundary to secondary containment.

CORRECTIVE ACTION. BEING TAKEN A one-inch drain line is beinq added to the bottom of the 10" steam supply header to continuously drain the 10" header to the four-inch steam line to the RCIC turbine. The condensate will be drained by the drain trap at the low point of the four-inch line. A Project Fngineering Directive has already been issued (PED-215-Y,-2339) to add the one inch drain line.

8008m c6