05000259/FIN-2013003-03
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Finding | |
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| Title | |
| Description | The NRC identified an issue of concern associated with the April 14, 2009 2A Residual Heat Removal (RHR) Heat Exchanger (HX) raw water side inspection. It was determined that the licensee had failed to identify a degraded non-conforming condition of excessive fouling by Asiatic clams that exceeded the established tube plugging criteria. The NRC working with organizations such as the Electric Power Research Institute (EPRI) had provided information to nuclear power plant license holders regarding fouling issues with raw water heat exchangers. In 1989, the NRC issued Generic Letter (GL) 89-13 to provide approved means to address heat exchanger fouling. Browns Ferrys response to GL 89-13, originally committed the licensee to perform once per cycle inspection and cleaning of the RHR HXs and periodically perform thermal performance testing to prove continued operability per TVA letter dated March 16, 1990. Once per cycle during this period in time was once per 18 months. In this letter, TVA reported that they had observed issues with Asiatic clam fouling in their HXs. Browns Ferry later shifted the inspection and cleaning frequency to once every two years and then to once every four years without providing a basis or thermal performance testing of all the RHR HXs. On April 14, 2009, Browns Ferry performed a GL 89-13 inspection of the 2A Residual Heat Removal (RHR) Heat Exchanger (HX). TVA inspections documented results which included pictures of the raw water side of the HX. The pictures showed 245 tubes had shells that were either partially or fully obstructed by shells. This exceeded the maximum calculated 77 clogged tubes needed to maintain the HX operable. The TVA inspections failed to adequately document the visible Asiatic clam fouling, and did not enter the degraded non-conforming condition into the corrective action program, as required by NPG-SPP-03.1 Corrective Action Program section 3.1.R. This would have necessitated an operability evaluation, as required by NPG-SPP-09.14 Generic Letter 89-13 Implementation procedure. On April 24, 2013, the NRC challenged past operability of the 2A RHR HX from 2005 to 2009. The licensee stated that implementing a new revision to the NPG-SPP 09.14 procedure would prove operability. The update to the NPG-SPP 09.14 procedure for analyzing clam fouling was inadequate to prove operability. TVA then utilized a new (2012) Electric Power Research Institute (EPRI) analysis for determination of the effect of fouling on heat exchanger tubes to determine that the 2A RHR HX remained operable from 2005 to 2009. This method gives full heat transfer credit to any tube not greater than 85 percent clogged. Additional inspection of the licensees application of the EPRI guidance and operability determinations is required to provide additional information needed for the NRC to disposition this issue. This unresolved item was tracked as URI 05000259, 260, 296/2013003-03. |
| Site: | Browns Ferry  |
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| Report | IR 05000259/2013003 Section 1R15 |
| Date counted | Jun 30, 2013 (2013Q2) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | D Dumbacher D Jones J Hamman J Montgomery L Pressley M Riches S Shaeffer T Stephena Senguptac Stancil D Dumbacher J Montgomery J Rivera K Miller L Pressley M Riches P Niebaum R Hamilton R Kellner S Shaeffer T Stephen |
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Finding - Browns Ferry - IR 05000259/2013003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Browns Ferry) @ 2013Q2
Self-Identified List (Browns Ferry)
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