Duke Energy submitted its decommissioning plan to the Nuclear Regulatory Commission (NRC) this week for the company’s retired Crystal River nuclear plant in Florida.

The 860-MW plant, located about 85 miles north of Tampa, went into service on March 13, 1977. It has been shutdown since September 2009 when engineers discovered a delamination, or separation of concrete, within the containment building that surrounds the reactor vessel, while replacing two 500-ton steam generators during a scheduled maintenance and refueling outage. Crews successfully repaired the damage, but additional delamination was discovered in two different areas of the containment building in 2011.

Following a comprehensive, months-long analysis of costs, risks, and other factors, the company determined that retiring the plant was in the best interests of customers and shareholders. The company announced its decision on Feb. 5, 2013.

The NRC allows licensees to choose from three alternative decommissioning strategies: DECON, SAFSTOR, or ENTOMB. Duke Energy selected the SAFSTOR option. Under SAFSTOR, often considered “deferred dismantling,” a nuclear facility is maintained and monitored in a condition that allows the radioactivity to decay; afterwards, it is dismantled and the property decontaminated. Thus, the plant will be placed in a safe, stable condition for 60 years until decommissioning work is completed in 2074.

The estimated decommissioning cost is $1.18 billion in today’s (2013) dollars. Radiological and environmental monitoring will continue during the entire process and the plant’s used nuclear fuel will remain in the existing on-site fuel pool until a new, on-site, dry-cask storage facility is built.

“Decommissioning the Crystal River nuclear plant will be a well-defined process, with significant NRC oversight,” said Duke Energy Crystal River decommissioning director Terry Hobbs. “Nuclear safety will remain Duke Energy’s top priority. The plant will remain in a safe, stable condition, and our comprehensive emergency plan and 24/7 security force will remain in place.”

—Aaron Larson, associate editor (@AaronL_Power, @POWERmagazine)