05000454/FIN-2008003-06
Finding | |
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| Title | Unit 1 and Unit 2 Auxiliary Feedwater Tunnel Hatch Margin to Safety |
| Description | \"Late in the inspection period the licensee identified that the design analysis for evaluation of the AFW tunnel flood seal covers did not include the effects of a high energy line break in the main steam isolation valve tunnels at another facility. The NRC inspectors at that facility questioned why a dynamic load factor as a result of the impulse pressure following a high energy line break had not been considered in an analytic calculation perform to support the operability evaluation
Following a review of the licensees evaluation, the inspectors questioned the licensees conclusion that the operability of the AFW hatches continued to be supported despite analytical results showing a factor of safety for the concrete expansion anchors supporting the hatches of less than 2.0, which is contrary to the guidance provided in NRC Bulletin 79-02, Pipe Support Base Plate Designs Using Concrete Expansion Anchors. Additionally, the inspectors noted that the licensees evaluation did not address Section C.13 of NRC Technical Guidance 9900, Operability Determinations & Functionality Assessment for Resolution of Degraded or Nonconforming Conditions Adverse to Quality or Safety. Specifically, Section C.13 stated that if a structure was degraded, the licensee should assess the structures capability of performing it specified function. As long as the identified degradation did not result in exceeding acceptance limits specified in applicable design codes and standards referenced in the design basis documents, the affected structure was either operable or functional. The licensee also identified additional errors that reduced the margin of safety for the structural integrity of a high energy line break barrier. At the close of the inspection period temporary modifications had been implemented at both facilities that restored the margin of safety to greater than 2.0. Pending additional follow-up by the inspectors for the past operability and timeliness of corrective actions, extent of condition, and corrective actions, this item will remain open. (URI 005000454/2008003-06;05000455/2008003-06 \ |
| Site: | Byron  |
|---|---|
| Report | IR 05000454/2008003 Section 4OA2 |
| Date counted | Jun 30, 2008 (2008Q2) |
| Type: | URI: |
| cornerstone | No Cornerstone |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | A Dunlop D Mcneil R Langstaff R Winter R Ng C Thompson B Bartlett J Cassidy D Jones R Skokowski J Gilliam B Jonesb Bartlettc Acosta C Thompson C Zoia D Jones J Cassidy J Jacobson N Feliz Adorno R Jickling R Ng R Russell R Skokowski T Bilik V Meghani |
| INPO aspect | |
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Finding - Byron - IR 05000454/2008003 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Byron) @ 2008Q2
Self-Identified List (Byron)
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