energy
8:55 am
Tue July 3, 2012

Federal investigators probe Entergy over leaky tank at Palisades

This story has been modified to correct a metric conversion and the reference to the substance tritium.

The Palisades plant near South Haven has an aluminum water tank that’s used in case of emergencies or when the plant needs to be refueled. Last month, Entergy, the company that owns the plant, shut the reactor down to fix a leak in the tank.

Palisades knew the tank was leaking for longer than the company first said

It appears that the water tank has been leaking for a lot longer than the company first admitted.

When the plant shut down for repairs June 10th Palisades Spokesman Mark Savage said Entergy had been monitoring the leak for “several weeks” (an email he first sent to reporters said "several days"). But it turns out that they really knew about this tank leaking for more than a year.

A nuclear watchdog dug up an inspection published in August 2011. The Nuclear Regulatory Commission, the federal agency that regulates Palisades and other nuclear power plants, does the inspections.

The documents say there was water leaking into the plant’s control room on May 18th, 2011. Workers figured that it was rainwater getting into the control room.

But they also found a tiny leak in this huge water tank that rests above the control room.

Tiny is 400 milliliters (nearly 2 measuring cups of water) from a water tank that holds close to 300,000 gallons. Because it’s such a tiny amount they decide to fix the tank during the next planned refueling outage.

So when the plant shut down this past April to replace its spent nuclear fuel rods spokeman Mark Savage says the tank was drained and repairs began.

“The modification we made to what’s called the nozzle in the tank we thought was the leak source,” Savage said.

But when they fill up the tank it’s still leaking; probably worse than before. 32 days after the plant restarted the leak got as bad as 31 gallons day.

Is the water that leaked safe?

The water does contain "trace amounts" of tritium – a radioactive isotope of hydrogen. That's because the water comes into contact with the fuel at the plant, Savage said. He says the water leaking was collected in “catch basins” and will be reused in the tank once it is fixed.

Federal regulators note the water never left the building and is not a danger to workers or the public.

Federal investigators probe Palisades

Special federal agents launched an investigation into the leaky water tank last week. Entergy declined to comment on the open investigation and there’s not much the Nuclear Regulatory Commission can say about open investigations either.

But NRC Spokeswoman Viktoria Mitlyng would say the investigation isn’t about the current leak issues – it’s about the “historical handling” of the water tank leak.

“How much of a leak, and what did you know, when did you know it? Stuff like that – those are the questions that we have to wait before we can respond,” Mitlyng said.

I don’t know what they’re looking into but there was something that caught my eye in reviewing the federal documents.

When plant workers were figuring out where the water in the control room was coming from they had to go out of their way to check out some of the pipes connected to the water tank. Documents show the pipes hadn’t been inspected in 17 years even though they’re supposed to every 3.5 years.

“From the scaffold, personnel were able to enter the open areas and inspect the piping.  Accumulations of white residue were found on the floors, ceiling, and on some of the piping.  Some slight dripping from the roof was noted as well.  The licensee believes that the residue is a combination of boric acid and washout from the concrete roof.  Determination of the source of the roof leakage is still underway.”

The tank that’s leaking holds water with boric acid in it. The water is used to cool the plant’s reactor during planned refueling and emergencies.

More about the Office of Investigations

We don’t know exactly what these special investigators are looking into. We don’t know when they’ll conclude their probe. We do know that they determine “alleged wrongdoings” against nuclear plant operators, workers and contractors.

  • In 2011 the OI closed 121 cases
  • 85% of cases were closed within 9 months or less
  • They found “substantiated willfulness” in 40 of those cases
  • One of the 12 “significant cases” in 2011 stems from a Palisades employee

In that case a control room operator at Palisades left the control room without permission and without handing over controls to another worker.

“An OI investigation determined that an atthecontrols (ATC) reactor operator deliberately violated ATC procedures by improperly removing himself from his watchstanding responsibilities.  The ATC reactor operator admitted leaving his station despite knowing that he had not been given proper turnover or approval from the control room supervisor.  The ATC reactor operator further admitted leaving his station while the control room supervisor was telling him to stop.  This investigation was referred to DOJ for prosecution consideration.  The case remains under NRC regulatory review.”

The control room operator still works at the plant but Palisades Spokesman Mark Savage says he’s working outside the control room. The NRC outlined a number of steps he must complete before he’d be allowed to work in the control room again.