05000387/FIN-2014002-01
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Finding | |
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| Title | Adequacy of Compensatory Measures to Restore Technical Specification Operability |
| Description | An Unresolved Item (URI) was identified because additional NRC review and evaluation is needed to determine whether implementation of a compensatory measure to restore TS operability required NRC approval prior to implementation and to subsequently determine whether a violation of 10 CFR 50.59, Changes, Tests and Experiments was more than minor. During a review of a prompt operability determination addressing the inadvertent closure of a main turbine CV, inspectors questioned whether a compensatory measure specified to maintain compliance with TS required NRC approval prior to implementation. Specifically, to address the degraded condition, PPL implemented a compensatory measure of crediting plant equipment not previously credited in the UFSAR to restore and maintain operability in accordance with TSs 3.2.2, Minimum Critical Power Ratio and 3.2.3, Linear Heat Generation Rate. PPL did not perform an evaluation of this change as required by 10 CFR 50.59(d)(1). On July 10, the number 3 main turbine CV on Unit 1, XV-10150C, slowly drifted close while operating at 100 percent rated thermal power (RTP). In response to the issue, the electro-hydraulic control system opened CVs 1, 2 and 4 to maintain reactor pressure stable. Operators reduced power to approximately 96 percent RTP. Operators also generated CR 1724394 and assessed the condition for operability. PPL performed a prompt operability determination and assessed, in part, the potential affect the degraded condition had on the power distribution limits. Specifically, PPL determined, during discussions with the fuel vendor, that the thermal limits were affected by the number 3 CV being closed. Specifically, with the number 3 CV closed, the steam relieving capacity of the main steam system was below assumed values in the transient analysis for a Recirculation Flow Controller Failure (RFCF). The RFCF is one of the limiting events used to develop the flow-based Minimum Critical Power Ratio and Linear Heat Generation Rate thermal limits. To compensate for this and restore operability per TSs 3.2.2 and 3.2.3, PPL specified crediting the reactor recirculation motor-generator set high speed electrical and mechanical stops to limit the maximum flow assumed in the transient analysis. Consistent with Inspection Manual Part 9900 Technical Guidance, Operability Determinations & Functionality Assessments for Resolution of Degraded or Nonconforming Conditions Adverse to Quality or Safety and the PPL 50.59 Resource Manual, Revision 6, PPL considered this compensatory measure a change to the facility and assessed whether the change required prior NRC approval in accordance with NDAP-QA-0726, 10 CFR 50.59 and 10 CFR 72.48 Implementation, and PPLs 50.59 Resource Manual. PPL determined the change did not require evaluation under 10 CFR 50.59 and documented this on a 50.59 Screening Determination. In part, this was based on answering no to the question does the proposed activity involve a change to an SSC that adversely affects an FSAR described design function. The basis for this determination was that the reactor recirculation motor-generator set high speed electrical and mechanical stops are not credited in the FSAR transient analysis and, therefore, have no design function. PPL considered the effect on the design function of the fuel assemblies to not fail during normal operation and anticipated operational occurrences and determined that the compensatory measure ensures that the requirement of the design function is met. PPL concluded that the change did not adversely affect any of the design functions for the fuel. Inspectors reviewed the 50.59 screening determination and questioned the basis of PPLs conclusion that an evaluation of the change was not required. Specifically, the change had the effect of creating a new design function for the reactor recirculation motor-generator set high speed electrical and mechanical stops to limit flow during a RFCF event. Additionally, a failure of these components could preclude the design function of the fuel from being met. The resource manual provides a definition of adverse effects which states, in part: Changes that would introduce a new type of accident or malfunction with a different result would screen in. If a proposed change would reduce the reliability of a design function, this change should be screened in because there is an adverse effect on a design function. Changes to SSCs that are not explicitly described in the FSAR can have the potential to affect SSCs that are explicitly described in the FSAR and thus may require a 10 CFR 50.59 Evaluation. If for the larger FSAR described SSC, the change affects a FSAR described design function or an evaluation demonstrating that intended design functions will be accomplished, then a 10 CFR 50.59 Evaluation is required. In this case, the introduction of a new design function for the components and reliance on these components to function to ensure a design function of the fuel was met had an adverse effect by introducing a new potential malfunction that could result in the design function not being met. Therefore, inspectors determined that PPL should have answered Yes to the screening question Does the proposed activity involve a change to an SSC that adversely affects an FSAR described design function. PPL also should have evaluated whether the change needed prior NRC approval in accordance with 10CFR 50.59(d)(1). Inspectors determined that the issue was a performance deficiency, however, could not determine whether the change would ever have ultimately required NRC approval. Therefore, in accordance with the NRC Enforcement Policy, inspectors could not determine whether the performance deficiency was more than minor. PPL entered the issue into the CAP as CR-2014-09397 and initiated actions to evaluate the change in accordance with 10 CFR 50.59(d)(1). Pending completion of PPLs 50.59 evaluation and review by inspectors, this is a URI. |
| Site: | Susquehanna  |
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| Report | IR 05000387/2014002 Section 1R15 |
| Date counted | Mar 31, 2014 (2014Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | C Graves E Burket F Bower J Cherubini J Greives T Dauna Turilinb Smith D Dodson F Arner F Bower J Grieves S Hansell T Daun T Hedigan |
| INPO aspect | |
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Finding - Susquehanna - IR 05000387/2014002 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Susquehanna) @ 2014Q1
Self-Identified List (Susquehanna)
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