BRATTLEBORO -- Vermont Yankee nuclear power plant in Vernon reduced its power level Tuesday to 14 percent to allow technicians to repair an oil leak in one of the plant's two water recirculation pumps.
According to Neil Sheehan, spokesman for the Nuclear Regulatory Commission, on Tuesday, control room operators at Yankee received a low-oil-level warning for the "B" recirculation pump.
Power was reduced to allow technicians to enter the drywell surrounding the plant's reactor vessel to get a visual of the pump. They found a compression fitting on a pipe linking the oil reservoir to the pump was leaking. The seal was repaired and the oil reservoir was topped off.
"This is a maintenance issue," said Sheehan. "The kind that occurs from time to time in these plants."
The reactor was still at reduced power Wednesday afternoon following the repairs to allow the drywell to be refilled with nitrogen, an inert gas, which was drained during repairs.
"They believe that resolved the problem," said Sheehan.
While that repair was conducted, technicians discovered a blown fuse in the plant's steam jet air ejector, which removes gases from the condenser via suction and sends them to the plant's stack for disbursal to the atmosphere. The kinds of gases released during normal operations are xenon, krypton and argon, which have a very short half-life and rapidly decay.
Though the two recirculation pumps direct water through the plant's nuclear fuel during routine operation, they are not considered safety related. Boiling water reactors have other safety systems that are designed to inject coolant into a reactor vessel during emergencies.
Yankee's recirculation pumps have experienced problems in the past 10 years.
In the summer of 2012, power was reduced to 33 percent when the "A" recirculation pump tripped due to an electrical fault associated with the "A" recirculation pump motor generator set. In 2009, technicians replaced a circuit card in the motor generator control unit for the "A" recirculation pump. In 2003, a faulty seal in one of the pumps was replaced.
On Aug. 27, Entergy announced it would be closing Yankee sometime in the fall of 2014. Entergy representatives cited the effects of natural gas prices on Yankee's financial viability as the major reason for its decision to cease operations at the plant, which went online in 1972.
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