The Nuclear Regulatory Commission (NRC) said April 27 that it will tighten its oversight of the Exelon (NYSE:EXC) Oyster Creek nuclear plant in New Jersey after regulators reviewed problems linked with design aspects of electromatic relief valves, or EMRVs.
NRC said it was increasing oversight following the finalization of one “yellow” and one “white” inspection finding for the Lacey Township (Ocean County), N.J., facility. A yellow classification indicates substantial safety significance while a white finding means low-to-moderate safety significance.
“These enforcement actions underscore the need for plant owners to be vigilant when it comes to maintaining essential safety equipment,” NRC Region I Administrator Dan Dorman said. “In the case of these issues, two components that can play an important role during a reactor shutdown either experienced or may have experienced material failures that could have prevented them from performing their functions when needed,” he added.
“The company has since corrected the equipment problems. The NRC will now carry out additional inspections to ensure the underlying issues have been fully addressed,” Dorman went on to say.
Oyster Creek is about 60 miles east of Philadelphia in Ocean County, N.J. The plant produces 636 MW (net).
The boiling water reactor (BWR) was commissioned in 1969, according to GenerationHub data. The plant will retire by the end of 2019.
With respect to the “yellow” finding, the EMRVs would be used to depressurize the reactor during a pipe break to allow coolant to be injected into the reactor core. This is necessary to keep the nuclear fuel in the reactor covered and cooled as the shutdown progresses.
During refurbishment work in June 2014 on two EMRVs removed from the plant in 2012, the company found an alignment problem with the valve’s actuator. When the valves were tested, they did not open.
Once the issue was identified, Exelon immediately tested five of its then-installed EMRVs. All five actuated successfully. Further, the company installed redesigned actuators for the valves during a refueling and maintenance outage at the plant in October 2014.
Even though the violation involving the EMRVs has been classified as “yellow,” the NRC has determined it represents an old design issue. That is, the issue stems from an inspection finding involving a past design-related problem and does not reflect a current performance deficiency associated with existing programs, policies or procedures used by the company.
As a result, the finding will not lead to Oyster Creek moving into the Degraded Cornerstone Column of the NRC’s Action Matrix. However, the NRC will carry out a team inspection that will review Exelon’s root-cause evaluation and corrective actions for the issue.
On the issue involving one of the plant’s emergency diesel generators, the back-up power source may not have been available to operate because of the degradation of its cooling fan drive shaft.