05000346/FIN-2009002-04
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Finding | |
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| Title | |
| Description | The inspectors reviewed Calculation No. VF11/B00-016, FCR 78-126: Steam Generator Blowdown Line Pipe Whip Restraint R7, Revision 5, and Drawing No. C-299A, Auxiliary Building Steam Generator Blowdown Whip Restraint R7, Revision O. The design calculation and design drawing of the pipe whip restraint R7 were identified as nuclear safety-related (Q). As described in USAR Section 3.2.1.1, Class I structures, systems, and components are also defined as nuclear safety-related (Q) and are relied upon to remain functional during design basis events. The design function of the SGBD pipe whip restraint R7 was to hold and maintain the SGBD line in position and ensure that the restraint structure did not impact safety-related systems, structures, or components during a HELB event. The inspectors identified a non-conservative technical error in Calculation VF11/B00-016. The inspectors identified that the calculation of the pipe whip force did not include a DAF. The USAR Section 3.6.2.5.9 required restraint structures to withstand a pipe whip force, which is the product of the thrust multiplication factor, DAF, break flow area and maximum operating pressure. In response to the concern, the licensee initiated Condition Report (CR) 09-52701 on January 28, 2009. The licensee initiated a revision of the calculation and identification of the required modifications to ensure conformance with USAR Section 3.6.2.5.9 requirements. Near the end of the inspection period, the licensee provided the inspectors additional information relevant to the design basis of the restraint which will require additional review. Therefore, this issue is considered an unresolved item (URI 05000346/2009002-04) pending completion of inspector review and evaluation and, as appropriate, determination of risk significance. |
| Site: | Davis Besse  |
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| Report | IR 05000346/2009002 Section 4OA5 |
| Date counted | Mar 31, 2009 (2009Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | |
| Inspectors (proximate) | J Rutkowski T Go A Wilson J Bozga J Cameronc Browng Wright J Rutkowski A Wilson T Go J Bozga J Cameron P Voss |
| INPO aspect | |
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Finding - Davis Besse - IR 05000346/2009002 | ||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2009Q1
Self-Identified List (Davis Besse)
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