05000289/FIN-2010009-02: Difference between revisions
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| CCA = N/A for ROP | | CCA = N/A for ROP | ||
| INPO aspect = | | INPO aspect = | ||
| description = The inspectors identified a Green NCV of 10 CFR 50, Appendix B, Criterion III, "Design Control," associated with MSSV capacity calculations revised in 1988 to support a power, uprate amendment. The MSSV capacity calculations erroneously referenced the as-purchased capacity instead of the as-built capacity when determining if there was sufficient blowdown capacity following the power uprate. When the correct value was used, the calculation showed that the MSSVs did not have sufficient capacity. This is the calculation of record for this system and is the basis for the TS requirements that all MSSVs are required to be operable or a power penalty must be assessed. During the inspection, Exelon was able to demonstrate that the MSSVs did have the required capacity and the American Society of Mechanical Engineers (ASME) code safety function to protect the Main Steam System piping and once through steam generator (OTSG) integrity had never actually been iost. The issue was placed in the CAP. A License Amendment Request (LAR) is also being developed which will replace the calculation of record. Using an incorrect value for actual MSSVs relief capacity was a performance deficiency which was reasonably within the licensee's ability to foresee and prevent. This performance deficiency was more than minor because it affected the Design Control Aspect of the Mitigating Systems Cornerstone Objective of ensuring the operability, availability, and reliability of systems designed to mitigate transients and prevent core damage. The issue was also compared to the examples in NRC IMC 0612, Appendix E, "Examples of Minor Issues." The issue was similar to example 3j which states, "The violation of 10 CFR 50 Appendix B Criterion III is more than minor if the engineering calculation error results in a condition where there is now a reasonable doubt on the operability of a system or component." The team assessed this finding in accordance with NRC IMC 0609, Attachment 4, Phase 1 - "Initial Screening and Characterization of Findings," and determined that it was of very low safety significance (Green) since it was determined that the error did not actually result in a loss of the system's safety function. The issue did not meet all the criteria to be considered as an old design issue because it was not a licensee-identified issue. This finding was determined to not have a cross-cutting issue because the performance deficiency occurred in 1988 and was not indicative of current licensee performance. | | description = The inspectors identified a Green NCV of 10 CFR 50, Appendix B, Criterion III, \"Design Control,\" associated with MSSV capacity calculations revised in 1988 to support a power, uprate amendment. The MSSV capacity calculations erroneously referenced the as-purchased capacity instead of the as-built capacity when determining if there was sufficient blowdown capacity following the power uprate. When the correct value was used, the calculation showed that the MSSVs did not have sufficient capacity. This is the calculation of record for this system and is the basis for the TS requirements that all MSSVs are required to be operable or a power penalty must be assessed. During the inspection, Exelon was able to demonstrate that the MSSVs did have the required capacity and the American Society of Mechanical Engineers (ASME) code safety function to protect the Main Steam System piping and once through steam generator (OTSG) integrity had never actually been iost. The issue was placed in the CAP. A License Amendment Request (LAR) is also being developed which will replace the calculation of record. Using an incorrect value for actual MSSVs relief capacity was a performance deficiency which was reasonably within the licensee\'s ability to foresee and prevent. This performance deficiency was more than minor because it affected the Design Control Aspect of the Mitigating Systems Cornerstone Objective of ensuring the operability, availability, and reliability of systems designed to mitigate transients and prevent core damage. The issue was also compared to the examples in NRC IMC 0612, Appendix E, \"Examples of Minor Issues.\" The issue was similar to example 3j which states, \"The violation of 10 CFR 50 Appendix B Criterion III is more than minor if the engineering calculation error results in a condition where there is now a reasonable doubt on the operability of a system or component.\" The team assessed this finding in accordance with NRC IMC 0609, Attachment 4, Phase 1 - \"Initial Screening and Characterization of Findings,\" and determined that it was of very low safety significance (Green) since it was determined that the error did not actually result in a loss of the system\'s safety function. The issue did not meet all the criteria to be considered as an old design issue because it was not a licensee-identified issue. This finding was determined to not have a cross-cutting issue because the performance deficiency occurred in 1988 and was not indicative of current licensee performance. | ||
}} | }} | ||
Latest revision as of 20:41, 20 February 2018
| Site: | Three Mile Island  |
|---|---|
| Report | IR 05000289/2010009 Section 4OA2 |
| Date counted | Sep 30, 2010 (2010Q3) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71152 |
| Inspectors (proximate) | D Orr J Brand R Bellamy A Rao |
| INPO aspect | |
| ' | |