Exelon's Limerick Generating Plant in Montgomery County. Credit: Wikimedia Commons Exelon's Limerick Generating Plant in Montgomery County 20 miles outside Philadelphia. Credit: Wikimedia Commons

Three years ago this week, a tsunami caused by an earthquake led to a meltdown at a nuclear power plant in Fukushima, Japan.

Last week, on March 4 around 11:30 p.m., an Exelon Corporation nuclear power plant in Limerick, Pa., about 20 miles northwest of Philadelphia, was shut down after one steam turbine valve malfunctioned and closed.

"Operators in the control room monitor the plant 24 hours a day. When they received indicators that this had occurred, per procedures, they manually shut down the plant," said Exelon Limerick Generating Station communications manager Dana Melia of the incident.


The plant is still offline now as repairs and testing continue.

Melia pointed out that the valve malfunction, which prevented steam produced from nuclear rods heating water from escaping through the turbine, occurred on the "non-nuclear" side of the plant.

While the Fukushima meltdown was directly caused by Japan's natural proximity to tectonic fault-lines, which are not a threat to Pennsylvania as such fault-lines are nowhere near the state, Exelon Nuclear sought changes to make their plant safer after Fukushima, according to Melia.

"Three years after the events in Japan, Exelon’s nuclear facilities are even better prepared for the unimaginable," Melia said in an email.

They've added 17 diesel pumps at their nuclear facilities, and purchasing response trucks, hose trailers, supplies and emergency communication equipment for potential emergency response, and are spending $400 million across the board, Melia said.

They also verified the readiness of 1,700 pieces of equipment, inspected more than 1,900 flood barriers and seals, and invested more than 43,000 worker hours in checking equipment and procedures that could be relevant to an emergency situation, Melia said.


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