By Wayne Barber
Power provider Entergy is wrestling with regulatory issues for the spent fuel pool at its Pilgrim Nuclear Power Station, the Nuclear Regulatory Commission said in its latest quarterly report for the Massachusetts facility.
Entergy has announced plans to retire the 680-megawatt Pilgrim reactor by June 1, 2019, primarily due to continued low energy prices. Some locals want it closed earlier following a series of unplanned shutdowns and other incidents that put the plant under heightened NRC scrutiny.
In a May 15 report, the NRC cited two “Green” (very low safety significance) inspection findings and one NRC-identified Severity Level IV violation (which is effectively the same as a “Green” finding), according to a summary of the first-quarter inspection completed on March 31.
In one Green finding, the agency said Entergy had not as of May 27, 2016, ensured corrective measures had been enacted “to ensure compliance with spent fuel storage design requirements beyond September 2017 when testing results revealed gaps in neutron absorber material,” NRC spokesman Neil Sheehan said by email this week.
Since last July Entergy has submitted a licensee event report, along with a supplemental update, regarding the degradation of Boraflex neutron-absorption panels in the spent fuel pool at Pilgrim.
Evaluations conducted since spring 2016 suggested that panel degradation was worse than initially expected. Instead of the earlier estimate that about 534 Boraflex panels had experienced degradation that could make them less effective by September of this year, it was determined that approximately 885 Boraflex panels could face this situation. There are 4,963 Boraflex panels in the plant’s spent fuel pool, used in roughly 66 percent of fuel racks.
“Entergy late last year moved numerous spent fuel assemblies to other (non-impacted) racks to maintain the subcriticality requirements” to ensure there is no self-sustaining fission reaction within the pool, Sheehan wrote.
The latest inspection report says Entergy is preparing a root cause evaluation that will identify corrective actions to maintain Boraflex racks in the spent fuel pool within technical specifics beyond September.
An Entergy spokesman told RadWaste Monitor on Friday the company is working through its issues at the spent fuel pool.
“The NRC inspection report is important and we will carefully review all findings and observations,” Entergy said in a statement: “We work to continuously strengthen our ability to self- identify and resolve issues in a timely, effective manner.”
The company added that the NRC findings were entered into the formal corrective action program for Pilgrim: “We remain focused on safe and reliable operations and we will do everything to meet and/or exceed our regulatory requirements through shutdown in 2019.”
The other Green finding involves Entergy’s lack of compliance by March 1 of this year with internal steps “for exiting a technical specification limiting condition of operation, or the preparatory steps to commence an orderly shutdown of the reactor,” Sheehan said: “Specifically, the plant’s low-pressure coolant injection (LPCI) system’s ability to activate on low-low water level in the reactor vessel was taken out of service for longer than 12 hours, but control room operators did not implement internal procedure steps to prepare for a controlled reactor shutdown.”
The Severity Level IV breach involved Entergy’s failure to notify the NRC within the required four hours of initiation of reactor shutdown. Pilgrim operators initiated a shutdown on Dec. 16, 2016, due to a leakage involving the site’s main steam isolation valves, but did not submit official notification to the regulator until Feb. 13 of this year.
The NRC said in its report it is classifying all three violations as non-cited violations.
