Dry storage licence change supports faster decommissioning

10 April 2019

Orano TN's NUHOMS dry storage systems will be allowed to store used nuclear fuel with significantly shorter cooling times and higher decay heat under licensing amendments approved by the US Nuclear Regulatory Commission (NRC).

Orano TN's NUHOMS MATRIX dry storage module (Image: Orano)

The reduced cooling times - as short as two years - create flexibility for transferring used nuclear fuel from storage pools to dry storage pads at both operating and shut-down nuclear reactor sites, the company said. This is of particular significance for reactor sites scheduled for permanent shutdown, as it means the decommissioning milestone of "pool-to-pad" fuel transfer can potentially be completed years sooner. This in turn reduces site emergency planning requirements and costs, while enabling the site to accelerate plant decommissioning and achieve partial licence termination.

"These important evolutionary steps in our dry fuel storage technologies address the changing needs of the nuclear energy industry and deliver solutions that maximise value for all stakeholders," Orano USA CEO Sam Shakir said. "This expanded capability is another step forward in responsibly and safely managing used fuel while enabling shutdown reactors to efficiently transition into accelerated decommissioning."

When fuel is initially discharged from a nuclear reactor it is placed into "wet" storage in a used fuel pool, using pumps to ensure the circulation of cooling water. When it is subsequently placed in dry storage, it is typically transferred from the used fuel pool to metal canisters, which are then loaded into heavy concrete overpacks. These dry fuel storage systems do not require any power supply for active heat removal systems and have no moving parts. The higher heat dissipation capabilities of the NUHOMS system allows "short-cooled" fuel assemblies to be stored in configurations in the canisters that maximise shielding while maintaining safe temperatures, even under extreme conditions, the company said.

The amended licence also authorises the use of NUHOMS canisters to store and transport used nuclear fuel assemblies with increased burnup levels, rod and assembly damage, higher enrichment content, additional advanced cladding materials and new fuel assembly designs.

NUHOMS systems are currently in use at more than 30 sites around the USA, the company said.

Researched and written by World Nuclear News