On Friday, the Nuclear Regulatory Commission (NRC) announced it would issue certification for a new nuclear reactor design, making it only the seventh approved for use in the US. But in some ways it’s a first: The design, from a company called NuScale, is a small modular reactor that can be built in a central facility and then moved to where it will be operated.
The move was expected after the design received approval during the latest safety review in 2020.
Small modular reactors have been promoted because they avoid many of the problems that have made large nuclear power plants extremely expensive to build. They are small enough to be assembled on a factory floor and then shipped to the location where they will work, eliminating many of the challenges of custom on-site construction. In addition, they are structured to enable passive safety, requiring no operator action to shut down the reactor if problems arise.
Many of the small modular designs involve technology other than traditional reactors, such as using molten uranium salts as reactor fuel. NuScale has a much more traditional design, transporting fuel and control rods and energy through boiling water. Operatorless safety features include placing the entire reactor in a large pool of water, control rods inserted into the reactor by gravity in the event of a power failure, and convection-controlled cooling from an external water source.
NuScale started the certification process in 2016. According to the NRC, that process required the company to submit technical information that would allow the Commission to assess it as follows:
Applications must accurately analyze the correct response of the design to accidents or natural events. Applications must also include the inspections, tests, analysis and acceptance criteria that will verify the construction of key design features. In addition, the NRC requires design certification applicants to assess how the designs protect the reactor and the nuclear fuel pool against the effects of an impact from a large commercial aircraft.
Once completed, the certification will be published in the Federal Register, allowing the design to be used in the US. Friday’s announcement says the NRC is all set to take the publishing step.
The NRC will still have to weigh in at the locations where one of these reactors will be used. Currently, such a site is in the works: a project called the Carbon Free Power Project, which will be located in the Idaho National Lab. That is expected to be operational by 2030, but has faced some financial uncertainty. Utilities that could use the power produced there are hesitant to spend money on the project.