US nuclear company Holtec International has passed the first step of the UK’s Generic Design Assessment (GDA) with its SMR-300 small modular reactor (SMR) design.

The Office for Nuclear Regulation (ONR) carries out the GDA, along with the Environment Agency and Natural Resources Wales (NRW), to assess the safety, security and environmental protection aspects of the nuclear power plant design, which could be deployed across Britain.

Saffron Price-Finnerty, the Environment Agency’s new reactors programme manager, said: “We are assessing the environmental acceptability of a new small modular reactor design from US-based Holtec International, working with Holtec Britain, who are managing the delivery of the GDA in the UK. Holtec Britain has worked hard to grow the company sufficiently to be able to manage and deliver the project effectively.”

The GDA process has three steps: Step 1 began in October 2023 and focused on agreeing the Step 2 scope and schedule, which has now been successfully completed. Today marks the start of Step 2, which is expected to last for 14 months. 

“Holtec has completed all the requirements for Step 1 from the regulators' guidance with good progress made in developing its organisation and arrangements to support GDA,” the ONR said. “Today marks the start of the fundamental assessment of the design (Step 2), which is expected to last for 14 months.”

In May 2021, the UK's Department for Business, Energy and Industrial Strategy opened the GDA process to advanced nuclear technologies including SMRs.

Last year, the UK Government launched Great British Nuclear (GBN) to support new nuclear builds including the development of SMRs. SMRs, which are smaller and more easily transportable, have a capacity of up to 300MW(e) per unit and are a cornerstone of the GBN project.

Across the Atlantic, Holtec gained approval to restart the Palisades nuclear plant in Covert, Michigan, which ceased operation in May 2022.