The Nuclear Regulatory Commission is closely reviewing an April incident at Nine Mile Unit One that led to a failure of the shutdown cooling system. Our Candace Hopkins tells us what that means and if public safety was ever compromised.
SCRIBA, N.Y. -- Back on April 16th, Nine Mile Unit One was shut down for a scheduled refueling outage, when maintenance contractors accidentally cut the power to the shutdown cooling system.
The power was off for 32 minutes and during that time the temperature of the water inside the reactor rose 27 degrees. That water provides shielding and cooling for the nuclear fuel below and if it boils down enough, the fuel could melt.
"There's still a very large volume of water above the fuel, regardless, we don't want to see this type of event happen at any plants and this is a matter where there should have been greater adherence to procedure, greater precautions taken to ensure this didn't occur in the first place," said Nuclear Regulatory Commission Public Affairs Officer Neil Sheehan.
The NRC estimates it would have taken two hours for the water to boil and nine hours before that boiling would have damaged the fuel. Therefore, they say while this was a rare event, the public's safety was not compromised. Some nuclear power opponents, like the Alliance for a Green Economy, disagree.
"To me, this just underlines what a dangerous technology nuclear power is and how probably every day we're on the brink of a nuclear accident, it just takes one small error and not knowing what to do to fix the error, that could lead us down the road to a catastrophic accident," said the Alliance for a Green Economy Staff Organizer Jessica Azulay.
The Alliance for a Green Economy says one of their main concerns is that due to the scheduled refueling outage, some of the reactor's containment systems were not in use at the time. But the NRC and Nine Mile staff says that the risk of a radioactive release via the containment hatch was small, due to the backup water systems that were in place.
"We had water being added to the reactor vessel at that time from a system and we had four additional back up sources of water that could have been utilized, should it have been needed," said Constellation Energy Nuclear Group Spokesperson Jill Lyon.
So what does all of this mean? The NRC is now reviewing the incident and says it will determine the corrective actions needed going forward. The likely result would be increased NRC inspections at Unit One.
Unit One is already receiving additional oversight from the NRC, after exceeding the amount of unplanned shutdowns a reactor can have during a 7,000 hour operating period. They are scheduled to undergo a specialized inspection this November.