05000348/LER-2012-001
| Joseph M. Farley Nuclear Plant, Unit 1 | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3482012001R00 - NRC Website | |
Westinghouse -- Pressurized Water Reactor Energy Industry Identification Codes are identified in the text as [XX]
Description of Event
On February 15, 2012, with both Units 1 and 2 operating 100 percent power, during review of the new interpretation provided in NRC Information Notice 2012-01, it was determined that one of the items described in the information notice was applicable to the Farley Nuclear Plant (FNP).
Specifically, the information notice identified a utility that had received a non-cited violation (NCV) for crediting administrative controls to close a boundary valve to isolate the non-seismic piping system from the seismically qualified Refueling Water Storage Tank (RWST) [BP and BQ]. During the review, it was recognized that, considering the information provided in NRC Information Notice 2012-01, the RWST would be considered inoperable regardless of the administrative controls established when the RWST was aligned to non-seismic piping in Modes 1 — 4.
At FNP, the RWST is seismically qualified, safety related and within the scope of the plant Technical Specifications (TS). The plant design includes the capability to align the Spent Fuel Pool Purification (SFPP) system [DA] for cleanup of the RWST. The SFPP system is a non-safety, non- seismic system that is normally isolated from the RWST by a normally closed, safety related manually operated valve.
A review of system operating procedures identified that FNP allowed the SFPP system boundary valve to be opened under administrative controls while the unit was operating in Modes 1-4 without declaring the RWST inoperable per TS LCO 3.5.4 Condition B. TS LCO 3.5.4 Condition B requires that the RWST be returned to operable status with a completion time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. If the RWST is not returned to operable status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, TS LCO 3.5.4 Condition C requires that the unit be placed in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. FNP had a previous practice of aligning the seismically qualified RWST to the non-seismic SFPP system and a skid mounted Boric Acid Recovery System (BARS) for silica removal prior to refueling outages while in Modes 1 — 4. In addition, the RWST was also aligned to the non-seismic SFPP system piping during routine recirculation of the RWST to support TS required boron concentration verification. The BARS was placed in service for a period of approximately 22 days, on average, prior to each outage over the last five refueling cycles for each unit. The RWST on each unit was aligned to the SFPP system for recirculation on approximately a weekly basis for sampling purposes. Since the RWST was not declared inoperable during these periods, TS LCO actions were not entered. This resulted in operation of the units, which under the interpretation provided by NRC Information Notice 2012-01, is considered to be a condition prohibited by TS and is reportable pursuant to 10 CFR 50.73(a)(2)(i)(B),
Cause of Event
The direct cause of this event was an incorrect application of compensatory measures (i.e., manual operator actions) when placing the non-seismic SFPP system in service on seismically qualified systems/components (RWST) during modes of operation when they are needed to perform their safety function. Prior to the issuance of NRC Information Notice 2012-01, manual operator actions had been evaluated and deemed acceptable in accordance with procedures in place at that time.
However, it has been determined that licensees cannot use compensatory measures when compromising the seismic qualification of a system/component.
Safety Assessment This event had no significant safety consequence since a seismic event had not occurred while the SFPP system was in service on the RWST. Additionally this event did not involve a safety system functional failure since administrative controls were established and a designated operator was assigned to close the valve within a short period of time. This ensured the minimum required inventory in the RWST would have been available for accident mitigation requirements. This event would be considered low risk based on the following mitigating factors: very low frequency for a seismic initiating event; very low frequency of an accident requiring the use of the RWST safety function; operator action to isolate the non-seismic piping after a seismic initiating event; and a relatively small exposure time. The operator had sufficient response time based on a documented engineering analysis, had multiple cues, and had simple, proceduralized actions. Therefore, the health and safety of the public were not affected by this event.
It should be noted that subsequent to the NRC Information Notice 2012-01, a proposed Technical Specification (TS) was submitted that approved use of the alternate controls which were in place at the time of the event.
Corrective Action The BARS, in service for silica removal prior to the upcoming refueling outage, was isolated from the Unit 1 RWST. All RWST alignment to non-seismic piping was suspended for both units.
Procedures on both units were revised to use the seismically qualified Containment Spray system as an alternate means of recirculating the RWST prior to sampling.
Causal analysis was initiated and corrective action to strengthen procedure guidance related to 10 CFR 50.59 implementation was entered into the corrective action program (CAP). An additional condition report was entered into the CAP to resolve this seismic issue on a permanent basis.
Additional Information
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