Worker Action after MA Nuke Errors

Wednesday, July 12, 2017 @ 01:07 PM gHale


Pilgrim Nuclear Power Station management took action against employees for errors made in late March and early April that could have prevented safety systems from controlling the release of radioactive material if there had been an accident.

A March 27 incident at the Plymouth, MA-based facility, involved two technicians who heat-tested the wrong switch and caused the high-pressure coolant system to shut down temporarily. The two lost their qualifications to conduct such testing and were temporarily restricted from the plant, according to a report supplied by Pilgrim management to federal regulators.

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Under federal regulations, plant licensees must turn in reports looking at why certain events that could degrade safety systems occurred, who was at fault, what management did about it and what measures will be taken to prevent a recurrence.

Pilgrim had three such events within two weeks in late March and early April, for which management submitted the required reports.

On March 31, operators in the control room failed to follow standard procedure, shutting some valves in the wrong order after flushing some systems. The mistake caused water to flood from a massive storage tank into a reservoir at the base of the reactor known as the torus.

The torus plays a role in depressurizing and cooling down the reactor in a severe accident. It took operators about four hours to return the water level in the torus to its proper amount.

Based on that incident, the control room supervisor and reactor operator “were disqualified,” plant management said in its recent report to the Nuclear Regulatory Commission (NRC).

It was unclear just what action was taken, based on the wording in the report, said NRC spokesman Neil Sheehan.

“With respect to the control room operators who were disqualified because of the torus event, that can involve anything from a temporary removal from duties up to permanent dismissal,” Sheehan said.

Patrick O’Brien, spokesman for plant owner-operator Entergy Corp., said he could not provide more detail on the disciplinary action taken because it was a personnel matter.

The third event requiring a follow-up report occurred April 5, when operators rendered both trains in a standby gas treatment system inoperable for 49 minutes while they did testing.

Workers had shut down both fans in the treatment system at the same time.

The safety function of the treatment system is to reduce reactor building pressure so it limits the ground level release of airborne radioactive material.

“The actual consequences were a loss of safety function for the secondary containment system for about 49 minutes,” Entergy said in its report.

The solution was to train workers not to do it again.

The report noted the system had previously been inoperable in 2012, 2010 and 2004.

Entergy filed another event report on a more recent incident. With the reactor at full power, operators noticed both doors in one of the airlocks used to access the secondary containment room were open — an occurrence that should never happen.

Procedure calls for a worker opening one door in the airlock by turning a handwheel to release the locks, then stepping inside and shutting the door before opening the second one to prevent any release of radioactive material.

“Our resident inspectors are following up on this issue but have no safety concerns,” Sheehan said.



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