ML20127A474
| ML20127A474 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 06/14/1985 |
| From: | Miosi A COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 0246K, 246K, 85-02, 85-04, 85-2, 85-4, NUDOCS 8506210149 | |
| Download: ML20127A474 (2) | |
Text
D m (L Commonwealth Edison one First National Pla27, Chicago, Ilknots Address Reply to: Post Office Box 767 Chicago, Illinois 60690 June 14, 1985 Mr. James G. Keppler Regional Administrator U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137
Subject:
Byron Stati 1 Unit 2 Braidwood Station Units 1 and 2 10 CFR 50.55(e) 30 Day Report Seismic Qualification of Containment Floor Drain Valves NRC Docket Nos. 50-455 & 50-456/457
Dear Mr. Keppler:
On May 16, 1985, the Commonwealth Edison Company notified Mr. W.
L. Forney of your office of a deficiency reportable pursuant to 10 CFR 50.55(e) concerning the seismic qualification of the containment sump isolation valves RF026 and RF027 manufactured by Xomox Corporation. This deficiency was assigned number 85-02 for Byron Unit 2 and number 85-04 for Braidwood for your tracking purposes.
This letter fulfills the thirty day reporting requirements of 10 CFR 50.55(e) regarding this matter, and is considered to be a final report.
For Byron Unit 1, this matter was reported under 10 CFR 50.72 requirements.
DESCRIPTION OF DEFICIEK Y Recent review of the safety-related component list revealed that the data sheet no. C7001 for the Containment Sump Isolation Valves Nos.
RF026 and RF027 was not correct. These valves were specified as being passive and located in the auxiliary building, when in fact they should be considered active because of their containment isolation function, with the RF026 valve located in the containment building. The original Xomox qualification report was reviewed and approved for a passive function.
Subsequent investigation and conversations with the manufacturer, Xomox Corporation, revealed that these valves in their existing configuration were not qualified as active valves or for the requisite containment building accelerations.
8506210149 850614 PDR ADOCK 05000455 ANALYSIS OF SAFETY IWLICATIONS S
PDR If the containment isolation valves RF026 and RF027 had been required to function during and following a seismic event, there was no assurance that their safety function would have been accomplished.
If these valves did not close, a potential release path could exist via the containment floor drains which are open from the containment atmosphere to the radwaste system in the auxiliary building. From the radwaste system in the auxiliary building, a monitored release path exists to the,
yg 171985 atmosphere through the filtered ventilation system.
h0 M S ~1
5 J. G. Keppler June 14, 1985 CORRECTIVE ACTION TAKEN Due to the seismic qualification uncertainties, Xomox performed a seismic test on a sample valve unit representing our design. Without modifications, these valves could not be seismically qualified to building accelerations required by original procurement requirements. As a result, Xomox recommended the addition of a bolt-on bracket sub-assembly to increase the rigidity of the valve and actuator assembly, thus qualifying these valves for active service on Byron Unit 1.
The addition of these brackets required no disassembly or rework of existing components.
Subsequent calculations by Sargent & Lundy have shown that these valves are qualified for the actual Byron Unit 1 piping accelerations, which are considerably lower than the specified building accelerations, without the added brackets. However, the actual piping accelerations for the remaining units are not known at this time. We are proceeding with the qualification of the Byron Unit 2 and Braidwood Unit 1 and 2 valves.
The valves vary slightly from unit to unit utilizing different limit switch brackets, and different configurations as to what components are mounted remotely and on the valve. The final seismic qualification of the remaining valves may or may not require the addition of brackets. In any case, these valves will be qualified for active service on the remaining units prior to fuel load.
Please address any questions that you or your staff may have concerning this matter to this office.
Very truly yours, 0'il1?'
Anthony D. Miosi Nuclear Licensing Administrator 1m I
cc: NRC Resident Inspector - Byron NRC Resident Inspector - Braidwood Director of Inspection and Enforcement US Nuclear Regulatory Commission Washington, D.C.
20555 0246K l
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