By Wayne Barber
Duke Energy expects to finish building a dry cask storage facility at the retired Crystal River 3 nuclear plant in Florida sometime this year, and all used nuclear fuel assemblies will be transferred from the fuel pool into dry casks by February 2018, a utility spokesperson said this week.
Crews will begin moving used nuclear fuel assemblies from the spent fuel pool storage to the dry cask storage facility this summer, said Duke’s Heather Danenhower.
Following a competitive bid process, Duke selected SGT LLC as the engineering, procurement, and construction (EPC) contractor for the dry cask storage project. Based in Charlotte, N.C., SGT has extensive experience working with Duke at the Crystal River, Brunswick and Robinson nuclear power plants.
AREVA Nuclear Materials is the contractor for the fuel loading campaign, which will fill 40 dry casks, according to Danenhower.
Visible construction of the dry cask storage facility started in August 2015. Crews first removed the top layer of loose soil (called grubbing) and leveled the foundation, then drilled holes up to 60-feet deep and filled them with grouting, Danenhower said. This work provided a solid platform for 20-feet of backfill material that will hold the weight of 40 fully loaded dry casks.
Workers demolished one 90-foot-by-120-foot building, which was necessary to install a new security system for the dry cask storage project. The project team has placed all horizontal storage modules on the foundation, and preparations for the fuel loading campaign have begun, Danenhower said.
Duke is using the NUHOMS dry cask storage system from AREVA Nuclear Materials affiliate TN Americas. The NUHOMS system consists of stainless steel canisters that provide a confinement boundary for the assemblies and an overpack concrete housing. This housing provides structural and environmental support against natural disasters, such as hurricanes and tornadoes, and radiological shielding during storage. Duke Energy’s Oconee Nuclear Station near Seneca, S.C., and H.B. Robinson nuclear plant in Hartsville, S.C., have implemented a similar dry cask storage system, said the Duke official.
“The Crystal River Nuclear Plant decommissioning is progressing as expected – safely, on time and within budget,” according to Danenhower. “We are meeting our milestones, complying with all regulations, keeping state and federal regulators informed and currently focusing on the construction of an on-site dry cask storage facility.”
Duke Energy announced the retirement of CR3 in February 2013. The facility had been offline since its last refueling outage in October 2009 when a concrete separation problem was discovered.
Duke Energy would have needed to build a dry cask storage facility at Crystal River regardless of the decision to retire the facility because the on-site used fuel pool had nearly reached its capacity. Crystal River has stored its spent fuel on site since its first refueling in 1978.
Duke expects to spend $183 million to build the storage facility and move the fuel.
In July 2015, Crystal River 3 was placed in SAFSTOR mode, under which completion of decommissioning and decontamination can be delayed for up to 60 years. The site will remain in SAFSTOR condition until restoration is completed in 2074, according to a Duke website.
Decommissioning is expected to cost $1.18 billion in 2013 dollars, covering roughly $265 million for spent fuel management, $862 million for license termination, and $52 million for site restoration. The decommissioning trust fund for the power plant held about $715 million at the end of 2016. “With the SAFSTOR option, we believe the nuclear decommissioning trust fund, including future growth of the fund, is currently sufficient to decommission the plant without increasing customer bills. However, annual analysis will be needed,” Danenhower said.
