Orano achieves industry first in used fuel transfer

16 January 2020

Orano TN has completed the first transfer and storage of used fuel canisters with a higher than usual heat load using its Extended Optimised Storage (EOS) dry storage system. The use of EOS, which is licensed by the US Nuclear Regulatory Commission for heat loads of up to 50 kW per canister, means used fuel can be transferred to secure dry storage after a shorter period of time.

An EOS canister is 'down-ended' onto the horizontal transfer trailer for movement and loading at the onsite dry storage facility (Image: Orano)

On removal from a nuclear reactor, used fuel is transferred to a pool where it is allowed to cool sufficiently to be moved into dry storage or, in some countries, for reprocessing. Typically used fuel will remain in a pool for at least five years before this can take place. Heat load is a measurement of the used fuel's decay heat. Averaging a total heat load per EOS canister of 44.75 kilowatts, the EOS system is the first dry storage system to load and store used nuclear fuel with heat loads well above industry experience to date, which has ranged between 14-34 kW per canister, Orano said.

The transfer of 296 used nuclear fuel assemblies from the wet storage pool at a US reactor to the onsite dry storage Independent Spent Fuel Storage Facility (ISFSI) used eight EOS 37PTH canisters to securely store the used fuel in eight NUHOMS EOS Horizontal Storage Modules (HSM), Orano said.

Being able to transfer hotter fuel assemblies and fuel cooled for less time from wet to dry storage benefits operating nuclear facilities by simplifying the management of the pools and continuously reducing the wet-stored inventory of high heat and short-cooled fuel assemblies.

"The benefit is even greater for shutdown reactor sites. The EOS system allows a shutdown site to accelerate the transfer of used fuel from the pool to the ISFSI, enabling the site to shorten its transition period and accelerate updates to the facility’s emergency response plan," Orano said.

The Orano TN-designed EOS canisters are manufactured at Orano’s TNF site in Kernersville, North Carolina, and can store 37 high burnup pressurised water reactor fuel assemblies with the highest total heat load per canister, and the highest heat load per used fuel assembly, of any system in the industry, the company said. The EOS HSMs are manufactured at Orano’s precast concrete facility in Moyock, North Carolina, and engineered to provide maximum physical protection from external events, highest heat load dissipation capability and lowest radiation dose, with nearly half the dose rate of a vertical module system.

The loading campaign also saw another industry first, when the final two EOS canisters were loaded in an average of three-and-a-half days per canister. The previous record for an average canister loading was four days, Orano said.

Researched and written by World Nuclear News