PLYMOUTH — Pilgrim Nuclear Power Station leads the nation’s fleet of 99 reactors for incidents or conditions over the last 40 years that could have led to core damage and an accompanying release of radiation, according to a division of the Nuclear Regulatory Commission that conducts risk analysis.
While not among the 11 reactors on the 2016 list published June 8 by the NRC’s Division of Risk Analysis, Pilgrim has made the list for “accident sequence precursors” 23 times since 1980.
Such precursors are defined by the NRC as observed events or conditions that, when combined with one or more factors such as human error or equipment failure, could result in damage to the reactor’s core and a massive release of radiation.
“The accident sequence precursors are like golf scores, in that the low score wins,” said David Lochbaum, director of the Nuclear Safety Program for the Union of Concerned Scientists.
While the 45-year-old Plymouth plant, owned by Entergy Corp., was on the annual list only four times in the past 20 years, all four of the potentially dangerous incidents have been recent, occurring since 2011.
Since the fall of 2015, Pilgrim has been ranked by federal regulators in a performance category just one step above ordered shutdown, based on standards set by the Nuclear Regulatory Commission. Because of its ranking as one of the three worst performers in the country, Pilgrim was required to undergo 12,000 hours of federal inspection last year.
Lochbaum called the nature of the Pilgrim events on the accident sequence precursor list over the years “not surprising.”
“The list includes safety relief valve problems, losses of offsite power, and high pressure coolant system failures — the same problems that factored in recent Nuclear Regulatory Commission findings and sanctions,” he said.