05000259/LER-2018-001, Cancellation of LER 2018-001-00 for Browns Ferry Nuclear Plant, Fire Damage to Cables for Residual Heat Removal Service Water Valves Could Result in Water Hammer and Piping Damage

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Cancellation of LER 2018-001-00 for Browns Ferry Nuclear Plant, Fire Damage to Cables for Residual Heat Removal Service Water Valves Could Result in Water Hammer and Piping Damage
ML18320A263
Person / Time
Site: Browns Ferry  
Issue date: 11/16/2018
From: Hughes D
Tennessee Valley Authority
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 2018-001-00
Download: ML18320A263 (2)


LER-2018-001, Cancellation of LER 2018-001-00 for Browns Ferry Nuclear Plant, Fire Damage to Cables for Residual Heat Removal Service Water Valves Could Result in Water Hammer and Piping Damage
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition
2592018001R00 - NRC Website

text

Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 November 16, 2018 10 CFR 50.73 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Units 1, 2, and 3 Renewed Facility Operating License No. DPR-33, DPR-52, and DPR-68 NRC Docket No. 50-259, 50-260, and 50-296

Subject:

Cancellation of Licensee Event Report 50-259/2018-001-00, Fire Damage to Cables for Residual Heat Removal Service Water Valves Could Result in Water Hammer and Piping Damage

Reference:

Letter from TVA to NRC, Licensee Event Report 50-259/2018-001-00, dated May 15, 2018 (ML18135A247).

Consistent with the guidance in NUREG-1022, Revision 3, Sections 2.8 and 5.1.2, Browns Ferry Nuclear Plant (BFN) is cancelling (formally withdrawing) Licensee Event Report (LER) 50-259/2018-001-00.

The LER was submitted on May 15, 2018, pursuant to Title 10 of the Code of Federal Regulation (10 CFR) 50.73(a)(2)(ii)(B), as an unanalyzed condition involving the Residual Heat Removal Service Water (RHRSW) system with the potential to significantly degrade plant safety. Subsequent to the LER submittal, an independent analysis determined that functionality of the RHRSW system was maintained. Therefore, the condition no longer meets the reporting criteria of 10 CFR 50.73. A supplement to the LER was anticipated. This cancellation eliminates the need for that supplement.

On March 16, 2018, a potential unanalyzed condition was identified which could have affected the Residual Heat Removal (RHR) heat exchangers (HX) in a postulated fire event. It was discovered that the RHRSW HX piping associated with the credited HXs in the National Fire Protection Association 805 Nuclear Safety Capability Analysis could experience water hammer. A legacy condition existed where credited RHR HXs were subject to voiding due to single spurious opening of the RHRSW outlet valve and subsequent manual or spurious start of a pump. Spurious opening of the valves was recognized and addressed for flow diversion, but the potential effects of water hammer were not addressed. While this condition was being evaluated, the LER was submitted with the expectation that a supplement to the report would be submitted following completion of the evaluation.