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Interim Deficiency Rept,Condition 216 Re RHR Relief Valve Vents.Initially Reported 821022.Relief Valves Removed, Containment Leakage Path Eliminated & Steam Condensing Mode Deactivated.Next Rept Expected by 831103
	ML20076C094
Person / Time
Site:	Columbia
Issue date:	08/11/1983
From:	; WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	; NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20076C092	List: GO2-83-731, Forwards Interim Deficiency Repts for Condition 216 Re RHR Relief Valve Vents & Condition 270 Re Indeterminate Grade Matl on ECCS Pumps; ML20076C094; ML20076C096;
References
	10CFR-050.55E, 10CFR-50.55E, NUDOCS 8308220217
	Download: ML20076C094 (4)
	v • d • e

_ _ _ _ _ .

Attachment I WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT No. 2 DOCKET NO. 50-397 LICENSE N0. CPPR-93 10CFR50.55(e) CONDITION #216 RHR RELIEF VALVE VENTS INTERIM REPORT Description of Deficiency There are 4 RHR relief valves which have a 2" vent hole on the valve body.

The valves are RHR-V-55A, RHR-V-95A, RHR-V-558, and RHR-V-95B. These valves are situated such that the failure of a single motor operated valve, RCIC-V-113, would allow an open leakage path from the wetwell (primary contain-ment) directly to the reactor building (secondary containment).

The attached sketch illustrates the situation. Containment penetration X-116 is an open path into the wetwell's gaseous volume. In the steam condensing mode, RHR-V-55A (or B) and RHR-V-95A (or B) protect the RHR heat exchanger from over-pressurization. In order to accommodate condensation in the line between these valves and containment, a vacuum breaker has been installed that consists of penetration X-116, RCIC-V-113, RHR-V-102, RHR-V-101A (or B), RHR-V-103A (or B), and RHR-V-179A (or B).

All of these valves are normally open. Upon a containment isolation signal, the only valve to close would be RCIC-V-ll3. If it failed to close, and a LOCA had occurred, the wetwell would pressurize, and the wetwell atmosphere would vent down this path. Details of the RHR relief valve show that a flow path exists which would allow the wetwell atmosphere to vent directly to secondary containment.

Safety Implication Burns and Roe has estimated the gaseous release from these four paths at 5.2 x10 scfm during the first 450 seconds after a LOCA and at a rate of 4.9 x 10 scfm thereafter. This can be compared to the allowable release rate for primary containment of approximately 1.7 scfm.

Cause for the Deficiency The condition exists because the engineer did not recognize the relief valve had to serve a containment isolation boundary function, besides being a re-lief valve for RHR system equipment. Vendor drawings were evaluated only for the code related relief valve function without recognizing the hole in f@

.82 n.

the bonnet constituted a containment leakage path.

h u0 Corrective Action After a review of possible corrective actions, including incorporation of h a bellows seal, the Project has decided to remove the relief valves, elimi-J M

m ci nate the containment leakage path, and deactivate the steam condensing mode of the RHR system. Supply System and Burns and Roe Engineering are prepar-

"p q " ing the necessary~ Project-Engineering Directives and FSAR changes to imple-fg a n.u) ment the corrective-action. We will continue to provide your office with quarterly updates on this subject. The next report will be submitted by November 1, 1983.

Intsrim R2 port - #216 Page 2 of 4.-

Action to Prevent Recurrence Burns and Roe has reviewed all relief valves which can serve as the contain-

-ment boundary'and determined no other similar condition exists on WNP-2.

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