ML20217N841
| ML20217N841 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 03/31/1998 |
| From: | Reid D VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 50-271-97-12, BVY-98-49, NUDOCS 9804090224 | |
| Download: ML20217N841 (3) | |
Text
VERMONT YANKEE
..y NUCLEAR POWER CORPORATION
- '185 O'Id Ferry Road, Brattleboro, VT 05301-7002 (802) 257 5271 March 31,1998 BVY 98-49 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555
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Reference:
(a)
Letter, USNRC to VYNPC, NRC Inspection Report 50-271/97-12 and Notice of Violation, NVY98-29, dated March 3,1998
Subject:
Vermont Yankee Nuclear Power Station License No. DPR 28 (Docket No. 50-271)
Response to Notice of Violation: NRC Inspection Report 50 271/97-12 This letter is written in response to reference (a), which documents that certain of our activities were not conducted in full compliance with NRCrequirements. This violation, classified as Severity level IV, was identified duiing a NRC inspection conducted from December 7,1997 to January 24,1998. Our response to the violation is provided below.
S.tatement of Violation (50-271/97-12)
Vermont Yankee Technical Specification 6.5.A " Plant Operating Procedures," states that detailed written procedures shall be prepared, approved and adhered to includingfire protection program implementing procedures. The Vermont Yankee Safe Shutdown Capability Analysis, revision 5, dated November 19,1996, identified the High Pressure Coolant injection (HPCI) system as a safe shutdown system, and indicated that the wall that separates the HPCI roomfrom the torus room shallbe maintain J as afire barrierin accordance with Appendix A ofBranch TechnicalPosition APCSB 9.5-1, "Gu.i*linesfor Fire Protection for Nuclear Power Plants. "
Contrary to the above, the HPCI room Appendix A fire barrier wasfound to be inoperable on January 13,1998, in that the closure mechanismfor the associated automatic self-closingfire door was inoperable and the door would not close.
RESPONSE
Reason for the Violation Vermont Yankee Nuclear Power Corporation does not contest this violation. The cause of this violation was an inadequate design of the automatic self-closing fire door. This door was installed during original construction. The drop weight and cable attached to the back of the door provides motive force to pull the HPCI room door to a closed position when a fusible link is activated. The
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VERMONT YANKEE NUCLEAR POWER CORPORATION i
1 Docket No. 50-271 BVY 98-49' "
Page 2 of 3 cable passes from the door through a pulley to the weight. The cable was observed by a NRC inspector to be out of the pulley and resting on the pulley axle.
Trouble shooting of this door on January 13,1998 determined the most likely cause of the cable coming off the pulley was the combination of pushing the door further open than the normal full open position, the closure cable length and the size of the cable clamping devices. When the door was pushed further open than its normal full open position, the shon cable run to the pulley allowed the closest cable clamp to contact the illey and ride up on the pulley rim. Once in this position it could easily fall out of the pulley and come to rest on the pulley axle. This rendered the door automatic closure mechanism inoperative.
The automatic feature of the HPCI fire door is tested semi-annually in accordance with the
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applicable surveillance procedure and was last tested satisfactorily in October 1997.
Immediate Corrective Actions Taken and Resuhs Achieved (1)
Following discovery, the HPCI door was tested to determine if the door would self-close in the as-found condition. The door failed to shut. Troubleshooting was initiated to determine the cause and possible corrective actions. Once the cable was placed back into the pulley, the door closed p operly.
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(2)
Immediate corrective action included attempts to replicate the condition causing the cable to jump the pulley. This involved pushing the door past the full open position. After several trials, it was noted that it took one particular orientation of the large cable clamps riding up on the pulley to cause the cable to fall out of the pulley.
(3)
Pair.t was applied to the floor to indicate that this door is a fire dcor and should not be interfered with or blocked in any way.
(4)
The Fire Protection Engineer determined that there were no other fire doors with this type of automatic closing mechanism in the plant.
1 (5)
The failure mechanism that caused the door to become inoperable was discussed with the j
fire protection staff. This information was provided to increase awareness about off normal cond!'. ions that could be observed and prevented during routine fire protection tours.
J Actions Taken to Prevent Recurrence The existing cable clamps will be replaced with smaller, more streamlined crimped cable clamps.
This smaller clamp will easily be able to travel up into the cable pulley without causing the cable tojump out of the track. Free travel of the door past the full open position is needed to reset the door after testing activities or following door actuation. The smaller clamps wil: provide l
VERMONT YANKEE NUCLEAR POWER CORPORATION s
Docket No. 50-271 BVY N-49' "
Page 3 of 3 additional travel distance without the risk of the cable jumping out of the track. The new cable clamps will be installed by May 14,1998.
Date When Full Comoliance Will Be Achieved Compliance was achieved on January 13,1998 when the cable was placed back in the pulley and the HPCI fire door was verified to perform its intended function.
Should you have any questions about this matter please contact this office.
Sincerely, VERMONT YANKEE NUCIEAR POWER CORPORATION
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Donald A. Reid Senior Vice President, Operations cc:
USNRC Region 1 Administrator USNRC Resident Inspector-VYNPS USNRC Project Manager-VYNPS Vermont Department of Public Service
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