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| Quarter | Site | Title | Description | |
|---|---|---|---|---|
| 05000321/FIN-2017009-01 | 2017Q4 | Hatch | Failure to Implement Corrective Actions to Preclude Repetition of Reactor Scrams Due to IRM Spiking | A self-revealing non-cited violation (NCV) of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, was identified for the licensees failure to establish measures to assure that corrective action was taken to preclude repetition of a significant condition adverse to quality (SCAQ). Specifically, the licensee failed to implement corrective actions that would have increased the reliability of the intermediate range monitoring (IRM) system and prevent repetitive reactor scrams for similar reasons. The licensee entered this issue in the CAP as CR 10356172.The failure to ensure corrective actions were taken for a SCAQ to preclude repetition of reactor scrams due to IRM spiking caused by external electronic noise was a performance deficiency. This performance deficiency is more-than-minor because it is associated with the equipment performance attribute of the Initiating Events Cornerstone and adversely affected the cornerstone objective because it resulted in a reactor scram, which upsets plant stability and challenges critical safety functions during shutdown as well as power operations. Using Inspection Manual Chapter 0609 Appendix A, the inspectors determined that this finding is of very low safety significance (Green) because it did not involve the loss of mitigation equipment per Exhibit 1.B Transient Initiators. The inspectors determined that the finding had a cross-cutting aspect of Conservative Bias (H.14) within the cross-cutting area of Human Performance because the licensee failed to use decision making-practices that emphasize prudent choices over those that are simply allowable. |
| 05000390/FIN-2015002-01 | 2015Q2 | Watts Bar | Residual Heat Removal Flow Control Valves not Scoped in In-Service Testing Program | The NRC identified a NCV of 10 CFR 50.55a, Codes and Standards, for the licensees failure to meet the test requirements set forth in the American Society of Mechanical Engineers ASME Operation and Maintenance (OM) for Residual Heat Removal (RHR) flow control valves (FCVs). Specifically, TVA failed to scope the RHR FCVs into their In-Service Testing (IST) program. Immediate corrective actions included modifying the RHR pump testing procedures to perform the required remote position indication testing. The licensee entered this issue into their corrective action program as PER 995791. The performance deficiency was determined to be more than minor because if left uncorrected, the failure to perform required IST testing could lead to a more significant safety concern in that valve degradation could go unnoticed resulting in undetected inoperability. The inspectors determined that this finding was of very low safety significance (Green) because the finding did not represent an actual loss of function of a single train for greater than its TS allowed outage time. The performance deficiency had a cross-cutting aspect of Conservative Bias in the area of Human Performance because the licensee failed to use conservative decision making practices in their evaluation of the status of the RHR FCVs after being challenged by the NRC. |
| 05000390/FIN-2015002-02 | 2015Q2 | Watts Bar | Failure to Track ApplicableTechnical Specification Action Statement for Residual Heat Removal System | The NRC identified a NCV of technical specification (TS) 5.7.1.1.a, Procedures, for the licensees failure to implement OPDP-8, Operability Determinations and Limiting Conditions for Operations (LCO) tracking. Specifically, the licensee failed to track the applicability of action statement A of TS LCO 3.5.2.A, emergency core cooling systems, during planned testing. The licensee entered this issue into their corrective action program as CR 1010269. The performance deficiency was more than minor because, if left uncorrected, it would have had the potential to lead to a more significant safety concern in that, the failure to track an applicable technical specification action statement could lead to plant operations outside of TS analyzed conditions. The inspectors determined that this finding was of very low safety significance (Green) because the finding did not represent an actual loss of function of a single train for greater than its TS allowed outage time and did not represent an actual loss of function of one or more non-technical specification equipment for greater than 24 hours. The performance deficiency had a cross-cutting aspect of Avoid Complacency in the area of Human Performance because licensee personnel were complacent and failed to question long held assumptions about the ability of the valves to fail to their safe position under all design basis conditions. |
| 05000390/FIN-2015002-03 | 2015Q2 | Watts Bar | Failure To Consider The Effects Of A Break In Non- Seismic ERCW Piping | The NRC identified a NCV of 10 CFR Part 50, Appendix B, Criterion III, "Design Control," for the licensees failure to consider the effects of a break in the non-seismic portion of the essential raw cooling water (ERCW) discharge flow path to the cooling tower basin in the calculation used to determine the net positive suction head available to the auxiliary feedwater pumps. The licensee entered the issue into their corrective action program as problem evaluation report 97923 and has planned corrective actions to seismically qualify portions of the ERCW discharge path to the cooling towers. The performance deficiency was determined to be more than minor because it was associated with the mitigating systems cornerstone attribute of design control and adversely affected the cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences by potentially reducing the Net Posittive Suction Head (NPSH) available to the Auxillary Feedwater (AFW) pumps. The inspectors determined the finding to be of very low safety significance (Green) because the finding was a deficiency affecting the design or qualification of a mitigating structure, system, or component (SSC), and the SSC maintained its operability. The inspectors determined that no cross-cutting aspect was applicable because the finding was not indicative of current licensee performance. |
| 05000390/FIN-2015002-04 | 2015Q2 | Watts Bar | Failure to Follow Procedure during SSPS Testing | A self-revealing, Non-Cited Violation (NCV) of 10 CFR Part 50, Appendix B, Criterion V, Instructions, Procedures, and Drawings was identified for the licensees failure to follow procedure 1-SI-99-10-A, 62 Day Functional Test of Solid State Protection System (SSPS) Train A and Reactor Trip Breaker A, Revision 59 as amended, for troubleshooting by Procedure Control Form 070-4. Specifically, the licensee attempted to take voltage measurements which were not directed by the revised procedure. The licensee stopped testing, conducted a prompt investigation and removed the first line supervisor and foreman from their duties pending remediation. The licensee placed the issue into their corrective action program as CR 1015778 The performance was more than minor because it adversely affected the equipment performance attribute of the mitigating systems cornerstone to ensure the availability of systems that respond to initiating events to prevent undesirable consequences (i.e., core damage). Specifically, the failure to follow the troubleshooting procedure resulted in drawing an arc in the SSPS cabinet and tripping an upstream supply breaker which resulted in the inoperability of the 1A-A containment spray pump. The inspectors determined that this finding was of very low safety significance (Green) because the finding did not represent an actual loss of function of a single train of containment spray for greater than its Tech Spec allowed outage time. The performance deficiency had a cross-cutting aspect of Procedure Adherence in the area of Human Performance because crew members failed to follow the work instructions in the troubleshooting procedure (H8). |
| 05000390/FIN-2015002-05 | 2015Q2 | Watts Bar | Review of 10 CFR 50.59 Evaluation for the Emergency Diesel Generator Heat Exchanger | The inspectors identified an unresolved item (URI) regarding the licensees 10 CFR 50.59 evaluation for a modification to the operational configuration of the inlet motor operated valves (MOVs) for the EDG Heat Exchanger. Additional inspection would be required to determine if the licensees 10 CFR 50.59 evaluation properly addressed whether the modification resulted in more than a minimal increase in the likelihood of occurrence of a malfunction of a structures, systems, or components (SSCs) important to safety previously evaluated in the UFSAR. Watts Bar has four EDGs that are each cooled by two heat exchangers supplied by the ERCW system. Prior to the modification, flow through the heat exchangers was continuous due to the inlet MOVs (1-FCV-067-0066-A, 2-FCV-067- 0066-A, 1-FCV-067-0067-B and 22FCV-067-0067-B) being locked open. In order to ensure sufficient flow is available to components served by ERCW during dual-unit operations, the licensee modified the position of these MOVs from normally open with power removed, to normally closed with breakers closed. This resulted in the EDG heat exchangers being isolated during normal operation from the ERCW system. Flow, however, would be restored by the MOVs active function to open upon receipt of a signal from the EDG speed switch, should the EDGs startup. The inspectors reviewed the results of the licensees 10 CFR 50.59 evaluation related to the impact of the modification on the failure probability of the EDG. The inspectors concluded that additional information and review was necessary to determine whether the modification resulted in more than a minimal increase in the likelihood of occurrence of a malfunction of a system, structure, or component important to safety previously evaluated in the UFSAR. Particularly, the inspectors needed additional information on the specific inputs, assumptions, and evaluation methodology used to determine the increase in EDG failure probability. This issue was identified as URI 05000390/2015002-05, Review of 10 CFR 50.59 Evaluation for the EDG Heat Exchanger. |
| 05000390/FIN-2015007-03 | 2015Q1 | Watts Bar | Break In Non-Seismic ERCW Discharge Piping | The team identified an unresolved item (URI) related to the licensees failure to consider the effects of an open break in the non-seismic portion of the ERCW discharge flow path to the cooling tower basin in the calculation used to determine the net positive suction head (NPSH) available to the AFW pumps. This URI is to determine if the performance deficiency is More-than-Minor. The non-seismic normal discharge flow path of the ERCW system is to the cooling tower basin. The team noted that ERCW system description document WBNSDD- N3-67-4002, Essential Raw Cooling Water System, System 67, Revision 0028, stated, in part, that nonsafety-related ERCW system components shall be designed such that their failures do not jeopardize safety-related components. The team also noted that calculation EPMJKJ011191, WBN AFW System Pump Net Positive Suction Head (NPSH) Available Calculation, Revision 010, was used to determine the available NPSH for the AFW pumps. Upon review of this calculation, the team determined that the licensee failed to model the ERCW system considering an open break in the non-seismic portion of the discharge flow path to the cooling tower basin. A break of this type could result in a lower backpressure on the ERCW system, which could result in a reduction of available NPSH to the AFW during accident conditions. Subsequent to the inspectors questioning, the licensee entered the issue into their CAP as PER 979323. The licensee is performing an evaluation to determine the magnitude of the loss of available NPSH. This issue will remain open pending the teams review of the licensees evaluation in order to determine if the performance deficiency is More-than-Minor. |