ML20076H860

Advises That Reactor Coolant Gas Vent Sys (NUREG-0737,Item II.B.1) Not Operable & Will Not Be Operable by End of Refueling Outage.Exemption from 10CFR50.44(C)(3)(iii) Requested to Have Sys Operable Following Refueling Outage

ML20076H860
Person / Time
Site:	Beaver Valley
Issue date:	08/25/1983
From:	Carey J DUQUESNE LIGHT CO.
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
RTR-NUREG-0660, RTR-NUREG-0737, RTR-NUREG-660, RTR-NUREG-737, TASK-2.B.1, TASK-TM TAC-52184, NUDOCS 8309060226
Download: ML20076H860 (4)

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Telephone (412) 393-6000 Nuclear Division P.O. Box 4 Shippingport, PA 15077-0004 '

August-25,-1983 Director of Nuclear Regulatory Commission

• U. S. Nuclear Regulatory Commission Attn: D. G. Eisenhut, Director Division of Licensing Washington, DC 20555

Reference:

Beaver Valley Power Station, Unit No.1 Docket No. 50-334, License No. DPR-66 10CFR50.44(c)(3)(iii), Reactor Coolant System Vents and flVREG-0737 Item II.B.1 Gentlemen:

NUREG-0660 and 0737 provided NRC guidance for the design and installation of Reactor Coolant System Vents. On December 2,1981, the final rule presenting Interim Requirements Related to Hydrogen Control was published in the Federal Register (46 FR 58484). Included in this final rule was the requirement to provide improved operational capability to mair.tain adequate core cooling following an accident through the installation of high point vents for the reactor coolant system (RCS) by the end of the first scheduled outage of sufficient duration beginning after July 1,1982. The installation of this system has been completed and our procedures for_ operation of the system were submitted via Duquesne Light Company letter dated December 7,1982. Correspondence describing the Reactor Coolant Gas Vent System has been provided to the NRC via NUREG-0578 and 0737 correspondence dated 6/26/80, 7/1/81, 5/11/82 and 3/29/C3.

The Beaver Valley Power Station, Unit No.1 is presently completing work activities associated with the third refueling outage which is the first outage of sufficient duration after July 1,1982. At this time, the Reactor Coolant Gas Vent System (RCGVS) is not operable and will not be operable by the end of this refueling outage. In accordance with 10CFR50.12(a), a specific exemption is hereby requested from 10CFR50.44 (c)(3)(iii) to have an operable system following this outage. There are two reasons for not having an operable system; (1) not having URC authori-zation for use of the vent (2) the solenoid operated vent valves installed in our system have demonstrated ~an operational anomaly which requires resolution prior to declaring the system ready for operation. This anomaly was discovered during low pressure operation of this system. This system is manually isolated and de-energized during power operation.

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B; aver Valley Power Staticn, Unit No.1 Docket No. 50-334, Licensa No. DPR-66 10CFR50.44(c)(3)(iii), Reactor Coolant System Vents and NUREG-0737 Item II.B.1 Page 2 The pressurizer was at 300 psig with a steam bubble and the RCGVS was being used to depressurize the RCS by venting to the pressurizer relief tank (PRT). The RCGVS was initially lined up as shown on Figure 1.

The vent path was through S0V-RC-1038 and S0V-RC-104. When S0V-RC-104 was closed, 50V-RC-103A opened. It is postulated that while venting to the PRT, all the piping downstream of the restricting orifice is nearly at PRT pressure of 5 psig, since most of the pressure drop is across the restricting orifice. The low pressure at the inlet of S0V-RC-103A allows any water or high pressure steam in the bonnet above the disc to bleed off through the pilot orifice (see Figure 2). When S0V-RC-104 is shut, pressure in the lines builds up to 300 psig and this pressure is applied to the inlet and outlet of S0V-RC-103A, and forces the valve open. These valves were manufactured by the Target Rock Corporation (model number 808-001-1). This unexpected valve operation has been discussed with the Target Rock Corporation and the exact cause and steps necessary to correct this situation are currently under review.

It is our intent to resume operation from this refueling outage with the RCGVS isolated from the RCS by the manually operated isolation valves until this problem can be resolved. It is requested that a schedular exemption be granted from 10CFR50.44 to have an operable system following this outage. It is expected that the cause of this valve misoperation and the necessary actions to be taken to correct for this condition can be completed during the fourth refueling outage presently scheduled for February 1985. This would be the next outage of sufficient duration to make any necessary modifications to the system.

Since we do not have approval to operate the system during power operation or accident conditions pending your review of the procedures and no design basis accident necessitates its use, we believe this exemption should be granted on an interim bases until this problem can be adequately reviewed and resolved.

Very truly yours, J. J. Carey

"/A Vice President, Nuclear cc: Mr. W. fl. Troskoski, Resident Inspector U. S. Nuclear Regulatory Commission Beaver Valley Power Station Shippingport, PA 15077 U. S. Nuclear Regulatory Commission c/o Document Management Branch Washington, DC 20555 Mr. Steven A. Varga, Chief Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Operating Reactors Branch No.1 Division of Licensing Washington, DC 20555

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