05000324/FIN-2011013-01
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Finding | |
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| Title | Failure to Properly Assemble Reactor Vessel Head Following Maintenance Outage |
| Description | On November 17, 2011, the licensee determined that the reactor head flange was leaking due to inadequate reactor vessel head stud tensioning. Inspectors reviewed the licensees actions prior to the event and identified examples of improper procedure use and adherence that contributed to the inadequate reactor vessel head stud tensioning. Inspectors reviewed the completed Reactor Vessel Reassembly procedure (0SMO-RPV502) and determined that the refuel floor team failed to properly pressurize the RPV head stud tensioner to the values specified in 0SMP-RPV502 Attachment 1, which required a tensioner pressure of 13,000 lbs to achieve the desired stud elongation. Specifically, the refuel floor team interpreted an indicated tensioner pressure of 1300 lbs to be 13,000 lbs because the tensioner operators did not know how to correctly interpret the reading on the tensioner display. The RPV studs where under-tensioned due to this error. Procedure 0SMO-RPV502, Reactor Vessel Reassembly, step 7.15.12 requires QC to verify stud tensioning has been satisfactorily completed by reviewing and signing RPV head stud tensioning data table Attachment 1. The inspectors also determined that QC failed to verify proper RPV stud elongation in accordance with stud elongation values provided in 0SMP-RPV502. Although the verification was signed, none of the required stud elongation readings matched the acceptance criteria.nProcedure TRN-NGCC-1000, Conduct of Training, requires training be conducted per the biennial period Training Matrix. The training matrix requires that refueling floor personnel receive initial qualification (MB81) for reactor vessel reassembly per Lesson Plan ME501B. However, the qualification for ME501B has not been maintained by maintenance personnel performing RPV disassembly and reassembly, and the training associated with qualifications has not been updated to include current practices/tools or provided to any workers since 2000. As a result, nine of the twelve refuel floor personnel performing reactor vessel reassembly on November 13, 2011, did not have the refuel floor support training qualification (MB81) and failed to properly tension the reactor studs upon reassembly of the reactor vessel. 0PLP-20, Post Maintenance Testing, requires plant equipment shall be tested consistent with their safety functions following maintenance activities that may have impaired proper functioning of the component. The team determined that the licensee failed to specify an adequate PMT to test the pressure retaining capability of the RPV head. |
| Site: | Brunswick  |
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| Report | IR 05000324/2011013 Section 4OA5 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 93812 |
| Inspectors (proximate) | R Musserr Taylorr Musser E Stamm |
| INPO aspect | |
| Finding closed by | |
| IR 05000325/2012007 (20 April 2012) | |
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Finding - Brunswick - IR 05000324/2011013 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Brunswick) @ 2011Q4
Self-Identified List (Brunswick)
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