A leak too small to measure, discovered during a scheduled outage at the Davis-Besse nuclear power plant, has been classed as a "non-emergency".
In a report to the US Nuclear Regulatory Commission (NRC), First Energy Nuclear Operating Co (Fenoc) noted that a crack in the decay heat removal system at the Davis-Besse nuclear power plant was discovered by a welding operator preparing to work on the line, who spotted a small leak. The reactor, near Toldeo, Ohio, is currently off line for refuelling and maintenance. The leakage was too small to quantify the leak rate, and the event has been categorized as a "non-emergency". Planned refuelling activities are continuing.
According to press reports, Fenoc is planning to conduct ultrasonic testing on the weld and then come up with a repair plan. The discovery of the leak is not expected to have a significant impact on the length of the outage.
The unit spent two years offline after the discovery in March 2002 of severe corrosion in the reactor pressure vessel head caused by an undetected leak of boric acid.
US Nuclear Regulatory Commission