The Palisades nuclear power plant returned to service last week after being shut down for the last four weeks due to leaks from an aluminum water tank which holds 300,000 gallons of critical borated water used for emergency core cooling systems, the containment spray system, or planned refueling outages.
After Palisades spokesman Mark Savage said on June 10th, 2012 that the workers had been monitoring the leak for “several weeks,” a nuclear watchdog found an inspection report which documented water leaking into the plant’s control room on May 18th, 2011.
Entergy voluntary shut down the plant June 12th once the leak reached more than 31 gallons in a day. The tank is 50 feet in diameter, 35 feet tall, and made up of a bunch of aluminum plates welded together. 26 of these plates alone make up the bottom of the tank.
On Tuesday, the NRC issued a Confirmatory Action Letter to Entergy, the utility which operates the Palisades plant.
Some of the Entergy commitments to the NRC include:
– Measure and trend daily leakage from the tank.
– Declare the tank inoperable if the leakage reaches 38 gallons per day.
– If the tank is actively leaking, take actions to repair the tank in accordance with applicable safety standards.
– Continue to inspect the concrete support structure above the control room, control room hallway and control room ceiling.
– Correct the condition related to water seepage through the concrete support structure into the control room prior to the restart from the 2013 refueling outage.
Palisades spokesman Mark Savage says they found “several minor through wall leaks” (Seven through-wall leaks were identified according to a summary of meetings between Palisades and the NRC) in the aluminum walls and some flaws in the welds themselves and repaired them all.
We have a team assembled on site to look at long-term fixes. We continuously monitor tank operation, as it is critical to the plant’s nuclear safety,” Savage added.
As of June 11th, the current leakage from the tank was estimated at 16 gallons per day, according to the NRC summary document, although workers were not certain how much of this leakage was directly from the tank.
Earlier this year nuclear regulators downgraded Palisades’ safety rating to one of the worst in the country.
A third party investigation of the plant was carried out earlier this year by Conger & Elsea Incorporated, which reported evidence of “a lack of accountability at all levels at the plant.”
“The Team believes that there is a lack of confidence and trust by the majority of employees (both staff and management) at the Plant in all levels of management to be open, to make the right decisions, and to really mean what they say. This is indicated by perceptions around the decisions that have been made, the mixed messages and lack of adherence to expectations by management and supervision, and in the repeated emphasis of production over safety exhibited through decisions around resources.”
“There is a lack in the belief that Palisades management really wants problems or concerns reported or that the issues will be addressed,” the report’s executive summary stated.
Source: Michigan Radio
Source: Holland Sentinel