Holtec International's HI-STAR 100MB transport package has been certified by the US Nuclear Regulatory Commission (NRC). The company says the cask is "destined to become America's workhorse for transporting used nuclear fuel".

Typical transport configuration of the HI-STAR 100MB cask (Image: Holtec)

The HI-STAR 100MB is an enhanced version of the HI-STAR 100 package - which was initially licensed in 1998 - to transport high burn-up fuel in either a multipurpose canister (MPC) or in a basket. It is based on the HI-STAR 190 cask designed for retrieval of large-diameter canisters from US nuclear power plants with on-site storage facilities. The HI-STAR 100MB is the counterpart that will retrieve medium-sized canisters containing fuel with high burn-ups and shorter cooling times than allowed by the HI-STAR 100.

"Among the technology differentiators of the HI-STAR 100MB are its ability to ship contents packaged in an MPC or in a 'bare basket', to transport both moderate burn-up and high burn-up fuel in the various sizes employed in light water reactors, and to transport fuel with as little as 3.5 years of decay after discharge from the reactor," the company notes.

Holtec submitted its application for the HI-STAR 100MB to the NRC in February 2018. At that time, the company said that as the cask and fuel package designs were directly based on current designs approved by the NRC, it expected an "efficient review process".

Holtec announced yesterday that the design had received certification from the NRC.

"The certification of HI-STAR 100MB at present includes the high capacity canister, MCP-32M, and 'bare baskets' F-24M and F-32M, all using Metamic-HT as basket material for optimal performance," the company said. "The cask is however sized to hold any canister loaded in the industry up to 68.5 inches (1.74 metres) in diameter which means almost every canister commissioned into dry storage in the US before 2014."

Together with the larger HI-STAR 190 - which is sized to transport the extra-large canisters deployed in the past five years as well as some larger legacy canisters - Holtec says the HI-STAR 100MB will provide the means to safely transport used fuel from nuclear power plants across the USA to its consolidated interim storage facility, HI-STORE CIS, or directly to a repository.

In March 2017, Holtec submitted a licence application with the NRC for the HI-STORE CIS facility, which will be located in the US state of New Mexico. The company proposes to install its Hi-Storm UMax system, which would see casks of used fuel placed below ground in a concrete lot. The initial storage capacity of HI-STORE CIS is 10,000 storage canisters.

"Developing ever more robust transport casks with ever more versatility to make fuel transport on our nation's railroads ever safer is a core mission of our Nuclear Power Division," said Stefan Anton, Holtec's vice president of engineering and licensing. "HI-STAR 100MB exemplifies our new generation of transport casks that fulfil the above mission in full measure."

Holtec also expects "strong demand" for the HI-STAR 100MB from overseas customers. In March 2018, it announced that the design had won an international tender launched by China National Nuclear Corporation.