ML18153D131

Update to 920703 Special Rept Re Operational Difficulties W/ Waste Gas Decay Tank Hydrogen Monitors.Operability Intermittent & Reliability Not Yet Achieved.Ts Change to Delete Requirement to Monitor Hydrogen Sent on 920628

ML18153D131
Person / Time
Site:	Surry
Issue date:	09/15/1992
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
92-354A, NUDOCS 9209240043
Download: ML18153D131 (2)

Text

e VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 September 15, 1992 U. S. Nuclear Regulatory Commission Serial No. 92-354A Region II - Suite 2900

• SPS/MDK/GDM R4 101 Marietta Street, N. W. Docket No. 50-280 Atlanta, Georgia 30323 50-281 License No. DPR-32 DPR-37 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS l AND 2 SPECIAL REPORT UPDATE WASTE GAS HOLDUP SYSTEM H2 MONITORING INSTRUMENTATION

• In our letter dated July 3, 1992 (Serial No.92-354), we provided a special report that discussed operational difficulties with the Waste Gas Decay Tank (WGDT) hydrogen*

monitors. We committed to provide an update to the report if the hydrogen monitors were not restored to an operable condition by July 31, 1992. The modifications described in the report have been completed, and the monitors have been returned to service. However, operability has been intermittent and improved reliability has not beer achieved. Consequently, we are submitting this letter to provide additional information regarding our continuing efforts to improve the operation of the hydrogen monitors. The oxygen monitors continue to operate satisfactorily.

Although we have implemented the corrective actions recommended by the vendors, the reliability of the hydrogen monitoring equipment has not improved. Consequently, we are assessing our alternatives to enhance system performance. We are presently evaluating a short term action plan to improve the reliability of our existing hydrogen monitoring equipment. We are also performing an overall system design review for potential design modifications in the long term. As noted in our previous letter, a Technical Specification change request was prepared and submitted to the NRC on July 28, 1992 (Serial No.92-486). These changes would delete the requirement to monitor hydrogen in the WGDTs, and would rely on monitoring and restricting the oxygen level in the tanks to avoid generation of a potentially explosive ga~ mixture.

Pending approval of the proposed Technical Specification change, efforts to maintain the operability of the hydrogen monitors will continue. Daily grab samples are taken 9209240043 920915

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e whenever the monitors are out of service to ensure compliance with the Technical Specifications.

Should you have any questions or require additional information, please contact us.

W. L. Stewart Senior Vice. President - Nuclear Attachment cc: U. S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Mr. M. W. Branch NRC Senior Resident Inspector Surry Power Station