The U.S. Nuclear Regulatory Commission (NRC), the regulatory body that governs nuclear energy, on Friday announced that it would be issuing a certification to NuScale’s small modular reactor (SMR) design for use in the United States.

NuScale Power, a U.S.-based company that designs and markets SMRs, submitted a design certification application (DCA) to 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, the NRC issued a final safety evaluation report (FSER) for NuScale’s 50-MWe module design in August 2020 as part of a Phase 6 review — the last and final phase —of NuScale’s Design Certification Application (DCA). The design approval is the first issued for a U.S. small modular reactor.

“An application for a nuclear power plant combined license that references a certified design will not need to address any of the issues resolved by the design certification rule. Instead, the combined license application and the NRC’s safety review would address any remaining safety and environmental issues for the proposed nuclear power plant. The design certification approves the NuScale reactor’s ‘design control document,’ which is incorporated by reference in the final rule,” the NRC said on Friday.

The small modular reactor measures 65 feet tall x 9 feet in diameter. It sits within a containment vessel measuring 76 feet tall x 15 feet in diameter that can produce up to 50 megawatts of electricity.

The design uses natural, “passive” processes such as convection and gravity in its operating systems and safety features while producing up to approximately 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 energy sector by keeping financial costs lower. They are smaller than conventional nuclear reactors and typically have an electrical power output of less than 300 MWe or thermal power output of less than 1000 MW.

They are designed to be manufactured at a plant and transported to a site to be installed, eradicating many of the challenges of custom, on-site construction, and increasing containment efficiency. In the event of an emergency, a reactor could be shut down without water, power, or intervention from 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 any need for additional water, power, or even operator action. Nuscale’s scalable design offers the benefits of carbon-free energy and reduces the financial commitments associated with gigawatt-sized nuclear facilities.

The certification will be effective 30 days after the NRC publishes that rule in the Federal Register. Once published, NuScale’s SMR will become only the seventh reactor design certification that the regulatory body has issued for use in the U.S.

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