Arlington, TX—(ENEWSPF)—June 27, 2011. The U.S. Nuclear Regulatory Commission (NRC) is monitoring events at the Fort Calhoun nuclear power plant after a protective berm holding back floodwaters from the Missouri River collapsed early Sunday.
The plant, located about 19 miles north of Omaha, Neb., remains in a safe mode under an Unusual Event declared on June 6 because of flooding along the river. It is operated by Omaha Public Power District.
The 2,000 foot long water-filled berm provided supplemental flood protection to the plant, but was not required under NRC regulations.
It collapsed about 1:25 a.m. Sunday as a result of onsite activities. This allowed floodwaters to surround the auxiliary and containment buildings, which are protected by design to a floodwater level of 1014 mean sea level. The Missouri River is currently at 1006.3 feet. River levels are not expected to exceed 1008 feet.
The collapse of the berm also allowed floodwaters to surround the main electrical transformers. Operators transferred power from offsite sources to the emergency diesel generators as a precautionary measure due to water leakage around the concrete berm surrounding the main transformers. Efforts are underway to reconnect to offsite power once all safety checks have been completed.
NRC inspectors were onsite at the time and responded to the event. They have verified that reactor shutdown cooling and spent fuel pool cooling remain unaffected. NRC augmented its resident inspection staff on June 6, to provide around the clock coverage of site activities. The plant has been shutdown since April 7 for a refueling outage. In response to the event, the NRC has activated its Incident Response Center from which it is monitoring events. NRC Chairman Gregory Jaczko plans to visit the site today.