05000255/FIN-2014002-03
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Finding | |
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| Title | Spent Fuel Pool Region II Criticality Analysis |
| Description | The inspectors identified an Unresolved Item (URI) regarding assumptions used in the criticality analysis for Region II of the licensees spent fuel pool. Specifically, several assumptions in the applicable criticality analysis, which supported compliance with TSs and NRC regulations for criticality, did not appear to bound the characteristics of some fuel assemblies stored in Region II of the spent fuel pool. Description: On November 5, 2013, the licensee initiated CR-PLP-2013-04775, Issues Identified with Region II of Spent Fuel Pool Critically Analysis, which documented that the spent fuel pool criticality analysis was not updated following a power uprate that had been implemented in 2004. This was identified during the licensees review of industry operating experience documenting a similar issue at a different power plant. The licensee identified the following concerns with the criticality analysis for Region II of the spent fuel pool: 1) the assumed fuel temperature depletion parameter did not appear to bound the actual temperature for Batch A fuel, 2) the assumed cycle boron concentration did not appear to bound the actual cycle boron concentration after Cycle 20, and 3) the assumption that all Promethium-149 has decayed to Samarium-149 prior to placement of fuel into the spent fuel pool did not appear to be directly translated into site procedures. These concerns ultimately focused on whether fuel had achieved adequate burnup prior to placement in Region II of the spent fuel pool. The criticality analysis stated Batches A, B, and C fuel from Cycle 1 would not qualify for storage in Region II of the spent fuel pool due to extremely low burnup. However, Batch A fuel had been stored in Region II since a spent fuel pool re-rack project in 1987. Most of the Batch A fuel was relocated to dry storage in 1994 and 1995, but nine Batch A fuel assemblies currently remain stored in Region II. As a result of the assumptions that appeared to not bound actual conditions, Operations requested an Operability Evaluation to further evaluate the issue. Operability Evaluation CR-PLP-2013-04775 was assigned on November 5, 2013, and completed on December 5, 2013. The inspectors reviewed the Operability Evaluation along with staff from the Spent Fuel Team in the Office of Nuclear Reactor Regulation (NRR), Division of Safety Systems (DSS). On March 20, 2014, the NRC discussed the following questions regarding the Operability Evaluation with the licensee: The licensee compared the post-uprate hot leg temperature to the reactor core temperature in the analysis of record to justify that the analysis was bounding. However, the core temperature was hotter than the hot leg temperature, thus the Operability Evaluation did not appear to demonstrate that the existing core temperature was bounded by the core temperature in the analysis of record. Technical Specification Table 3.7.16-1 did not appear to ensure compliance with 10 CFR 50.68, which addressed spent fuel criticality, or TSs 4.3.1.3.a or 4.3.1.3.b, both of which addressed design assumptions in the Region II fuel storage racks. The methodology used in the development of the analysis of record contained non-conservatisms that appear to be mitigated by design margins that were already credited elsewhere in the Operability Evaluation. On March 25, the NRC questions were entered into the licensees CAP as assignments 6 and 7 of CR-PLP-2013-04775 with due dates of April 8. At the conclusion of the inspection period, the NRC staff was waiting to review the responses to the questions provided on March 20. This is an URI pending NRC review of the requested additional information. |
| Site: | Palisades  |
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| Report | IR 05000255/2014002 Section 1R15 |
| Date counted | Mar 31, 2014 (2014Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | A Garmoe A Scarbeary E Duncan J Cassidy J Lennartz T Bilika Garmoea Scarbeary E Duncan E Sanchez Santiago G Hansen J Cassidy J Lennartz M Jones M Phalen T Bilik T Taylor |
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Finding - Palisades - IR 05000255/2014002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Palisades) @ 2014Q1
Self-Identified List (Palisades)
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