Holtec International's canister-based dry used fuel storage technology is set to be deployed in Japan following its signing of a Memorandum of Understanding with Hitachi-GE Nuclear Energy. Holtec said its technology provides an alternative option to the technologies currently used in Japan.
The final canister of used fuel was loaded into the HI-STORM UMAX dry storage system at the San Onofre plant in California in August (Image: Holtec)Holtec noted the used fuel storage technology options traditionally used in Japan are challenged by certain unique conditions such as "regulator-mandated extremely low radiation limits, conservative regulatory release limits and extremely high seismic levels".
"The team believes an ideal candidate that can be optimised to meet Japan's industry's needs is Holtec's HI-STORM UMAX (Universal MAXimum shielding) dry storage system with a strength-welded transportable canister," Holtec said. "The HI-STORM UMAX stores the canister vertically inside stainless-steel structures surrounded by a concrete overpack and the canister is laterally supported at its top and bottom extremities to render it capable of withstanding ultra-strong earthquakes.
"The HI-STORM UMAX system is qualified for 2.12g resulting horizontal and 1.0g concurrent vertical seismic loadings, which exceeds that of any other licensed system in the world; indeed, it exceeds the strongest recorded earthquake in human history."
Holtec said this design provides the highest level of safety and security to the public by offering high reliability for radiation shielding and containment of radioactive materials, even in the most severe environmental events. The HI-STORM UMAX system is currently in use at two nuclear power plants in the USA, it noted.
Used fuel held within a Holtec storage system can be temporarily stored on-site at the power plant until a final location is identified for long-term storage. Holtec said the compatible transportation cask is the HI-STAR 190, which was licensed by the US Nuclear Regulatory Commission in 2017.
The HI-STAR 190ML - a slight variation of the HI-STAR 190 accepted by Ukraine's State Nuclear Regulatory Inspector of Ukraine for VVER fuel - has already been manufactured and delivered for transportation of canistered fuel to the Ukraine Central Storage Facility from Ukraine's nine nuclear reactors.
Holtec's agreement with Hitachi-GE, whose metal casks have been previously licensed and implemented in Japan for storage, will introduce its technology to Japan.
"The MoU will synergise the expertise of both team members to offer a solution that addresses the unique conditions and regulatory regimen in Japan and the heightened need for stringent storage requirements focused on protecting public health and safety in the country," said Rick Springman, Holtec's senior vice president of international projects.
Researched and written by World Nuclear News