05000341/FIN-2015008-03
Finding | |
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| Title | Inadequate 10 CFR 50.59 Evaluation for the On-Line NobleChemTM Process |
| Description | The inspectors identified an Unresolved Item (URI) associated with 10 CFR 50.59 evaluation 10-0286. Specifically, during review of Engineering Design Package (EDP) 36240, and associated 50.59 evaluation 10-0286 Revision A, the inspectors identified a URI associated with the licensees evaluation of the calculated hydrogen accumulation in balance of plant (BOP) piping sections and the consequences of a potential hydrogen detonation in the BOP piping sections on the accident frequency described in the final safety analysis report (as updated). In EDP 36240, Rev. A, On-Line Noble Chemistry Injection Skid Implementation Related Plant Changes, the licensee approved modifications to the feed system, which provided the equipment needed for addition of the catalytic materials used in the OLNC process. On November 15, 2012, the licensee approved Safety Evaluation (SE) 10-0286 Provide Evaluation of Noble Metal Solution Injected into Reactor Feed System, Revision A (EDP 36240). In this SE, the licensee documented their basis for implementation of the OLNC process which introduced/deposited noble metal catalysts onto the wetted surfaces of the reactor, fuel, and associated pipin
systems. Because the OLNC deposited platinum material on the wetted surface of reactor plant components, the licensee considered the impact of this change on the reactor coolant system, and attached piping system functions. The licensee evaluated the catalytic effect of OLNC to potentially increase the failure probability for 6 piping areas in the BOP piping systems susceptible to hydrogen accumulation, and potential detonation events originally identified by the licensee in CARD 02-12570. In its evaluation, the licensee concluded that diffusion within the BOP pipe segments, and out into the Mitigating Systems piping would effectively offset potential hydrogen accumulation such that detonable levels of hydrogen (approximietly15 percent) would never accumulate in BOP pipe segments. The licensee provided the inspectors with reference documents GE-NE-0000-0007-4008-01, Revision 0, BWR Piping and Component Susceptibility to Hydrogen Detonation, and GE-NE-0000-0003-1981-01, Revision 0, Report of the GENE Pipe Rupture Task Force, that provided the bases for the licensees use of diffusion as a credible mechanism to mitigate hydrogen accumulation. However, the inspectors determined that the reference reports did not provide any provisions for the use of diffusion as a credible mechanism for reducin hydrogen buildup. Therefore, the inspectors questioned whether the licensees technical basis for the application of the diffusion mechanism to evacuate hydrogen accumulation from the BOP segments as documented in the licensees SE 10-0286 Revision A, adequately demonstrated that hydrogen accumulation will not exceed detonation limits. In addition, the inspectors questioned the effects that a potential hydrogen detonation in these BOP segments would have on the frequency of occurrence of accidents previously evaluated in the UFSAR. The licensee entered this issue into their CAP as CARD 15-21102, 50.59 Evaluation Technical Basis Deficiency. This URI will remain open pending the inspectors review of the additional information to determine: (1) whether reasonable technical basis exists to support crediting diffusion as a means to mitigate hydrogen accumulation in BOP piping sections; and (2) whether the consequences of a potential hydrogen detonation in BOP piping sections are bounded by existing UFSAR analyses. (URI 05000341/2015008-03, Inadequate 10 CFR 50.59 Evaluation for the OLNC Process) |
| Site: | Fermi  |
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| Report | IR 05000341/2015008 Section 1R17 |
| Date counted | Mar 31, 2015 (2015Q1) |
| Type: | URI: |
| cornerstone | Barrier Integrity, Initiating Events, Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.17 |
| Inspectors (proximate) | A Shaikh B Kemker G Hansen J Wojewoda M Kunowski P Smagacz R Walton S Bell T Brileya Dahbura Shaikh J Corujo-Sandin R Daley |
| INPO aspect | |
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Finding - Fermi - IR 05000341/2015008 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Fermi) @ 2015Q1
Self-Identified List (Fermi)
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