05000237/FIN-2012008-04
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Finding | |
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| Title | Unit 2 East and West LPCI Corner Rooms Internal Flooding Event Issue |
| Description | The inspectors reviewed Engineering Change (EC) 386469, Repair of Flood Seals for Unit 2 West LPCI Corner Room Penetration No. 5 and No. 10 on Flood Seal Drawing FL-37 and East LPCI Corner Room Penetration No. 9 on Flood Seal Drawing FL-41 , Revision 3. Section 4.1.4.1 of this EC stated the function of the flood seal penetrations No. 5, 9 and 10 was to prevent water from leaking from the Torus basement into the Reactor Building corner rooms where the LPCI and Core Spray pumps are located. The LPCI and Core Spray pumps are safety-related. The purpose of this EC was to repair the aforementioned existing flood seal penetrations. The repair to the existing flood seal penetrations was classified per the EC as non-safety-related. In Revision 1 of this EC, the classification of the modification was changed from safety-related to non-safety-related. The licensee made this classification change to the EC because they concluded that the flood seal penetrations do not perform a safety-related or accident mitigation function as described by their current license basis. Also, the licensee described the flood seal penetration as being conservatively classified as safety-related because the licensee had not assigned a classification to the flood seal penetrations. During a walkdown of the flood seal penetrations, the inspectors identified non-safety-related fire protection and service water piping in close proximity to the non-safety-related flood seal penetrations. The inspectors noted that the non-safety-related piping was not designed and licensed to withstand a Class 1 earthquake event and failure of the piping could result in an internal flood in the torus basement which could generate a flood height that could reach and bypass flood seal penetrations No. 5, 9 and 10. During this inspection, the licensee was unable to locate an evaluation of whether or not the non-safety-related piping could withstand a Class 1 earthquake event or an evaluation to determine the flood height generated by a failure of the non-safety-related piping that would flood the torus basement when subjected to a Class 1 earthquake event and determine whether the flood could reach and bypass the flood seal penetration. In response to this concern, the licensee initiated Condition Report (CR) 01338733, Mod/50.59: Addl Info Needed for Non-Seismic Piping, dated March 8, 2012. The inspectors also discussed this issue with staff in the Office of Nuclear Reactor Regulation (NRR). After the exit, the licensee provided the inspectors additional information on IPEEE relevant to the design basis and licensing basis of the flood seals for the Unit 2 East and West corner rooms, which will require additional NRC review. Therefore, this issue is considered unresolved pending additional inspector review of the information provided by the licensee and consultation with NRR to determine the design and licensing basis requirements of the flood seals at Dresden. |
| Site: | Dresden  |
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| Report | IR 05000237/2012008 Section 1R17 |
| Date counted | Mar 31, 2012 (2012Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.17 |
| Inspectors (proximate) | J Laughlin T Go D Lords J Bozga J Cameron P Smagacz T Briley J Steffes G Roach D Melendez-Colon B Metrow C Phillips C Brown D Jonesd Szwarcj Bozga H Peterson Z Falevits |
| INPO aspect | |
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Finding - Dresden - IR 05000237/2012008 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Dresden) @ 2012Q1
Self-Identified List (Dresden)
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