Xcel Energy has temporarily shut its Monticello nuclear generating plant in Minnesota to repair a heat exchanger in the reactor's coolant system.

The plant was shutdown with all safety systems functioning, and without any release of radioactivity.

Operators shut the plant after noticing more-than-usual amounts of water in a system that cools its components, reported Star Tribune.

Xcel Energy spokesman Tom Hoen was quoted by the news agency as saying that the leakage occurred in pipes present inside the reactor’s containment structure.

”It was an operational issue that required a plant shutdown,” Hoen added.

The company will either purchase electricity from the Midcontinent Independent System Operator or other utilities or increase electricity production at its other generating plants to ensure an adequate power supply for the customers.

Owned and operated by Xcel Energy, the Monticello nuclear plant has a single-unit boiling water reactor, and generates 600MW of electricity.