Xcel said Friday that the leakage began earlier this week and spilled an estimate of “hundreds of gallons” of contaminated water at the Minnesota plant, caused by temporary repairs made to a defective section of the pipe.
“Upon investigation, operators discovered the temporary solution was, over the past two days, no longer capturing 100% of the leaking water,” the utility said.
Officials said that some 32% of the contaminated water had been captured so far and that there was no risk to the public or the environment.
The tritiated water did not make it into the drinking water supply and had not yet reached the Mississippi River, which runs alongside the plant.
However, it is the second time Xcel was forced to take its plant offline in the last two years due to a defective section of a pipe at the nuclear plant.
In November, the pipe leaked 400,000 gallons of tritium-contaminated water — news that was revealed to the public for the first time last week.
The first leak forced Xcel to make short-term repairs to solve the problem while it awaited a new, permanent pipe, which was scheduled for installation in April.
But the repair efforts may have fallen short since the new leak appears to be the result of the temporary fix.
Xcel said it would shut down the plant permanently until the damaged pipe section is replaced “to allow it to more quickly perform the repairs needed to permanently resolve” the spill.
It is unclear when the power plant will come back online for operations.