ML20107G859
| ML20107G859 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 10/09/1984 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 591, IEB-84-03, IEB-84-3, NUDOCS 8411080285 | |
| Download: ML20107G859 (5) | |
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VIRGINIA ELECTRIC A 1 OYEH CDMR Hrenwoxn,VrmoIMIA 20261 W.L.StuwAar vic e...
October 9, 1984 Nect.Au Or..asions Mr. James P. O'Reilly Serial No.
591 Regional Administrator N0/HLM/dn U. S. Nuclear Regulatory Commission Docket Nos: 50-280 Region II 50-281 101 Marietta Street, Suite 2900 Licesse No: DPR Atlanta, Georgia 30323 DPR-37
Dear Mr. O'Reilly:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT NOS. I AND 2 RESPONSE TO I.E. BULLETIN 84-03 We have reviewed I. E.Bulletin 84-03, " Refueling Cavity Water Seal",
dated August 24, 1984. An evaluation of the potential for and the consequences of a refueling cavity water seal failure.is provided in the attachment. Based on the evaluation and the design differences between the seals at Surry ar.d the failed seals at Haddam Neck, we believe that the refueling cavity water seal being used at Surry is adequate.
-The information contained in the attachment is true and accurate to the best of my knowledge and belief.
Should you have any farther questions, please contact us.
Very truly yours, r '
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W.. L. Stewart
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Attachment 108025koh ADOC o
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Vamoanu Enactnic Awo Powna COMPANY TO Mr. James P. O'Reilly cc:
U. S. Nuclear Regulatory Commission Attn: Document Control Desk (2)
Washington, D. C.
20555
- Mr. James R Miller, Chief Operating Reactors Branch No. 3 Division of Licensing Mr. D. J. Burke NRC Resident Inspector Surry Power Station s
SURRY POWER STATION RESPONSE TO IEB 84-03 REFUELING CAVITY WATER SEAL NRC QUESTION:
Action to be Taken By Plants Prior to Beginaing Refueling Or Within 90 days Of Receipt Of This Bulletin, Whichever Is Sooner:
Evaluate the potential for and consequences of a refueling cavity water seal failure and provide a summary report of these actions.
Such evaluations should include consideration of: gross seal failure; maximum leak rate due to failure of active components such as inflated seals; makeup capacity; time to cladding damaae without operator action; potential effect on stored fuel and fuel in tranrfer; and emergency operating procedures.
RESPONSE
Status-Surry Unit 1 is currently in a refueling outage with refueling cavity fill scheduled for October 13, 1984 and fuel movement shortly ~ thereafter.
Surry Unit 2 is scheduled for refueling in May of 1985.
Seal Description-The reactor cavity seal for both Surry Units is a straddle ring design which consists of a ring permanently bolted to the reactor cavity liner and a removable redundant seal between the reactor vessel flange and the straddle ring (See enclosure 1).
There are two 18 inch hatch openings in the straddle ring which are sealed by a machined surfaced and secured by 16 equally spaced bolts. The removable seal which is used during refuelings consists of a pressurized seal and a redundant passive seal. The pressurized seal uses inflatable gaskets (EPDM Material) to provide a watertight seal between the reactor vessel flange and the straddle ring.
A regulated air supply is used to inflate this seal. The redundant passive seal ("J-Seal") seals with water pressure and by compression.
Should the pressurized seal deflate, the passive sealing design will preclude failure and leakage.
Procedures
-equire a drop test of the pressurized seal and a physical
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inspection of the passive "J-Seal" prior to each use of the removable seal assembly.
Consequences-At least one path of makeup is available to the reactor cavity at all times during refueling. Should the pressurized seal fail due to overinflation, loss of air or other means, any of the available make-up paths (e.g. charging /HHSI pumps (600 gpm), IJISI pumps (3200 gpm), or RWST recirculation pumps (600 gpm)) could be used, if required, to maintain water level while the passiva "J-Seal" precludes leakage. Although a catastrophic f ailure is not credible because of the design, should such a failura occur, the ele ation of the spent fuel transfer system would prevent a fuel a sembly in the transfer system from being uncovered. In cddition, a barrier in the spent fuel storage pool precludes the draining of the pool's water through the transfer system to less than 13 inches above the fuel racks.
Conclusion-A complete failure of the reactor cavity seal ring assembly is not a credible ac.cident at Surry becsuse of the design and redundancy of the refueling cavity seal. As a result of this I.
E. Bulletin, the abnormal procedure applicable to fuel transf er has been modified and approved to further amplify necessary corrective actions to be taken gn a decreasing refueling cavity water level.
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