US regulators certify first small nuclear reactor design

NuScale Power Module

The U.S. Nuclear Regulatory Commission (NRC), the regulatory body that regulates nuclear power, announced Friday that it would issue certification for the design of NuScale’s small modular reactor (SMR) for use in the United States.

NuScale Power, a US-based company that designs and markets SMRs, filed a design certification application (DCA) with the NRC on December 31, 2016 to certify the company’s SMR design for use in the United States. It was accepted by the NRC in March 2017.

Later, in August 2020, the NRC released a Final Safety Assessment Report (FSER) for NuScale’s 50-MWe module design as part of a Phase 6 evaluation – the final and final phase – of NuScale’s Design Certification Application (DCA). The design approval is the first issued for a small modular reactor in the US.

“A nuclear power plant single permit application that refers to a certified design does not need to address any of the issues addressed by the design certification rule. Instead, the NRC’s single permit application and safety assessment would address all remaining safety and environmental issues for the proposed nuclear power plant. The design certification approves the NuScale reactor ‘design control document’, which is incorporated by reference into the final rule,” the NRC said Friday.

The small modular reactor consists of a 76-foot-high (23 meters), 15-foot-wide steel cylinder (4.5 meters) cylinder made of steel that can produce up to 50 megawatts of electricity.

The design uses natural, “passive” processes such as convection and gravity in its control systems and safety features, while producing up to about 600 megawatts of electricity. The SMR’s 12 modules, each producing 50 megawatts, are all submerged in a safety-related pool built below ground level.

SMRs have been promoted to facilitate the nuclear power industry by keeping financial costs low. They are smaller than conventional nuclear reactors and typically have an electrical capacity of less than 300 MWe or a thermal capacity of less than 1000 MW.

They are designed to be manufactured in a factory and transported to a site for installation, removing many of the challenges of custom construction on site and increasing containment efficiency. In an emergency, a reactor can be shut down without water, power or the intervention of a computer or operator.

NuScale has a much more traditional design, using uranium fuel rods to heat water in an internal pressurized loop. Its unique design allows the reactor to passively cool itself without the need for additional water, power or even operator action. Nuscale’s scalable design provides the benefits of carbon-free energy while reducing the financial obligations associated with gigawatt nuclear facilities.

The certification will take effect 30 days after the NRC publishes that rule in the federal registry. Upon publication, NuScale’s SMR will become only the seventh reactor design certification issued by the regulatory agency for use in the U.S.

The NRC has previously certified six other designs: the Advanced Boiling Water Reactor, System 80+, AP600, AP1000, the Economic Simplified Boiling Water Reactor and the APR1400.

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