05000456/FIN-2011003-06
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Finding | |
|---|---|
| Title | Asiatic Clams Identified in the Essential Service Water System Supply to the Auxiliary Feedwater System |
| Description | The inspectors identified an URI related to the licensees discovery of small clam shells in a portion of the 2A AF system train. At the conclusion of the inspection period, the licensee was still investigating the root cause of the event. On March 30, 2011, and May 9, 2011, the licensee discovered Asiatic clam shells (Corbicula fluminea) in a portion of the 2A AF system train. The shells were removed from the system upon discovery, but resulted in an 8-hour reportable event (EN 46868) because there were periods when the 2B AF train was not operable concurrent with this condition existing in the 2A train. The licensee concluded that although a more detailed review of past operability was still in progress, the size and quantity of shells removed from the piping on May 9, 2011, was greater than could readily be evaluated as operable without a more detailed analysis. The licensee identified that the shells were asiatic clams; common macro-fouling organisms in power station raw water systems. The licensee determined that clams of any species that are not commonly found in the SX system and their accumulation in the SX to AF crosstie suction piping was not consistent with other NRC Generic Letter (GL) 89-13 Service Water System Problems Affecting Safety-Related Equipment inspection results. At the end of the inspection period, the licensee was in the process of completing a root cause evaluation. The licensee concluded that the shell relics identified in the 2A AF system could be traced back to specific SX and chemical feed system conditions that existed in the 1990s. This URI will remain open pending an inspector review of the completed root cause evaluation, NRC Generic Letter 89-13 commitment review, and past operability and availability review. (URI 05000456/2011003-06; 05000457/2011003-06, Asiatic Clams Identified in the Essential Service Water System Supply to the Auxiliary Feedwater System) |
| Site: | Braidwood  |
|---|---|
| Report | IR 05000456/2011003 Section 1R15 |
| Date counted | Jun 30, 2011 (2011Q2) |
| Type: | URI: |
| cornerstone | Initiating Events |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | A Garmoe B Palagi D Reeser E Duncan G O'Dwyer J Benjamin M Perry R Nga Garmoed Betancourt E Duncan J Benjamin J Gilliam J Robbins M Perry N Adorno N Feliz Adorno R Ng T Bilik T Go V Meghani |
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Finding - Braidwood - IR 05000456/2011003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Braidwood) @ 2011Q2
Self-Identified List (Braidwood)
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