05000321/FIN-2010009-01
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Finding | |
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| Title | Acceptability of Liquid Filled Transformers in Fire Areas 2017 and 2019 |
| Description | The team identified an unresolved item (URI) involving the requirements for the installation of high-voltage liquid insulated transformers installed indoors. This item is unresolved pending receipt and review of additional documentation. FA 2017 and adjacent FA 2019 contained liquid insulated 4160-600 V transformers. The insulating liquid in these transformers was Dow Corning PMX-561, which is a combustible silicone based liquid with an ignition temperature of 460 oF. The team identified that the equipment in the FAs did not appear to be consistent with the requirements described in NRC Position D.1.g of Appendix A to Branch Technical Position (BTP) APCSB 9.5-1, Guidelines for Fire Protection for Nuclear Power Plants, dated August 23, 1976, in that the FAs contained both high-voltage-high-current transformers insulated with combustible liquid, and safety-related equipment, without enclosure in a three-hour barrier and installing automatic fire suppression. The north and west walls of FA 2017 and the north, east, and west walls of FA 2019 are credited as two-hour fire rated fire barriers. Additionally, the room comprising FA 2019 did not have a three-hour rated wall, and had a leakage path under the door such that transformer insulating fluid could spread to the adjacent FA. The Hatch FHA contained exemptions from certain requirements of 10 CFR Part 50, Appendix R for the above stated requirements, obtained at the time that 10 CFR Part 50, Appendix R became effective, but the exemptions were based on having negligible fuel loading in the FAs. The team determined that the exemption request was based on the licensees belief that the original transformer insulating liquid represented negligible combustible loading, which was not the case at the time of the inspection. During the inspection, the team attempted to determine the actual fire endurance capabilities of the walls surrounding FAs 2017 and 2019 as well as the fire rating of various masonry block wall penetrations. However, this information could not be ascertained during the inspection. The licensee initiated condition reports (CRs) 201000869, 2010115004, 2010115915, and 2010115986 to address these issues in their corrective action program. The matter is unresolved pending receipt and analysis of information from the licensee necessary to determine whether FAs 2017 and 2019 meet the requirements of Position D.1.g of Appendix A to BTP APCSB 9.5-1 and the licensees fire protection program licensing basis. An unresolved item, URI 05000366/2010009-01, Acceptability of Liquid Filled Transformers in Fire Areas 2017 and 2019, is being opened pending receipt and review of this information. |
| Site: | Hatch  |
|---|---|
| Report | IR 05000321/2010009 Section 4OA5 |
| Date counted | Dec 31, 2010 (2010Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | L Dymek M Bates R Carrion D Hardage E Morris J Hickey J Montgomeryf Ehrhardtm Thomas P Fillion G Wiseman R Nease P Braxton J Dymek |
| INPO aspect | |
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Finding - Hatch - IR 05000321/2010009 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Hatch) @ 2010Q4
Self-Identified List (Hatch)
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