Xcel, state regulators called in front of Senate committees over tritium leak

Called before a Minnesota Senate panel Wednesday, state regulators and an Xcel Energy executive addressed criticism of why they waited nearly three months to disclose a radioactive water leak at the company's Monticello nuclear power plant.

Xcel seemed to acknowledge it would have been better to notify the public sooner.

"People wanted us to share information earlier," Xcel Minnesota President Christopher Clark said at a joint informational hearing of the Senate energy and environmental committees. "We have definitely learned lessons about working with the communities that have been so supportive of us."

Xcel, the Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Health disclosed on March 16 that the plant had leaked 400,000 gallons of water containing tritium, a mildly radioactive form of hydrogen created in nuclear power production.

Xcel and regulators from both agencies reiterated Wednesday that the leak is contained to Xcel's property and poses no threat to human health or the environment.

Upon discovering high levels of tritium in an onsite monitoring well on Nov. 22, Xcel has said it notified federal and state regulators of a leak that day. On Dec. 19, the company discovered the leak's source: a pipe had broken in a half-inch space between two buildings.

Xcel contained the leak at the time, though the fix stopped working — and "hundreds of gallons" of water leaked — about a week after the March 16 announcement. Xcel then shut down the Monticello plant on March 24 and put in a new section of pipe to stop the leak. The plant reopened March 31.

The MPCA launched an investigation in November when Xcel reported the leak, Kirk Koudelka, an assistant MPCA commissioner, told the joint senate committee. Xcel also informed the MPCA in December about the leak's cause, he said.

"It is the company's duty to collect information and share it," he said. "In this case, we had a cooperative party [in Xcel]."

Xcel started cleaning up the tritiated water in January. In the middle of that month, the company's monitoring wells had shown that an underground tritium plume had moved closer to the Mississippi River, Koudelka said.

However, the plume remained confined to Xcel's property and tritium was not detected in the nuclear plant's drinking water, which is drawn from wells near the site, he said.

In February, the MPCA got its first estimates about the size of the leak. Regulators continued to collect information from Xcel and made a public disclosure when they had a clear picture of what happened.

A premature announcement could cause unwarranted "fear" among the public, Koudelka said. If there was "imminent danger," regulators would have notified the public immediately, he said.

Dan Huff, an assistant commissioner at the Minnesota Department of Health, told the joint committee that the nearest private water wells are more than a mile away from the Monticello plant — and they are uphill.

"We don't anticipate the [tritium] plume will ever reach those wells," he said.

Huff said that even if the 400,000 gallons of leaked water made its way to the river all at once — "and it won't" — it would not pose a threat to the Twin Cities' water supply.

The tritium would be diluted and "probably not even detectable," Huff said. "We do not have a concern it will pollute drinking water."

Xcel said it's doing a full metallurgical analysis of the failed pipe. The company said it will also do a thorough inspection of the plant when it shuts down for refueling for a month starting Friday.