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NuScale’s newly approved reactor module could generate 77 megawatts of electricity, compared with 50 megawatts in its earlier approved design. That increase—54% per module—was the central commercial change behind a May 29, 2025, Nuclear Regulatory Commission decision.
The NRC granted standard design approval for US460, a plant configuration with six modules. At 77 megawatts each, their combined electrical output would be 462 megawatts. The approval gave prospective developers a reviewed design to reference in their applications for specific nuclear projects.
It did not authorize a power station to begin construction or operation. The NRC expressly said companies using the design would still have to apply for those permissions. For a customer considering nuclear electricity, May settled a design-review question while leaving project development ahead.
More output from the modular approach
The US460 configuration retained natural processes, including convection and gravity, in its operating systems and safety features. Its modules would be partially immersed in a safety-related pool below ground. NuScale described the uprated design as retaining the fundamental safety case of its earlier module, with selected changes to accommodate higher power.
The numbers also require attention to units. NuScale rated each module at 250 megawatts thermal and 77 megawatts electric. The former measures heat from the reactor; the latter describes electrical output. The two ratings should not be added together or treated as competing estimates of the same thing.
DOE’s May 30 account described the design as using factory-built modules. That manufacturing approach is part of the proposed delivery model. Approval of the design does not demonstrate that a complete plant has been assembled, commissioned or operated at the stated output.
The NRC accepted the US460 application for review in July 2023 and based its approval on a final safety evaluation issued in May 2025. The earlier US600 design, with 50-megawatt modules, had received certification in 2023. Keeping the names and outputs separate avoids attributing the new design’s capacity to the older approval.
The commercial work continues
NuScale said its partner ENTRA1 held exclusive global commercialization, distribution and deployment rights for its technology. In the May announcement, the company described a goal of deployment by 2030. That was a forward-looking business schedule, rather than a date established by the regulator.
DOE also reported that NuScale was performing front-end engineering for RoPower’s planned 462-megawatt station in Romania. Engineering a proposed project is another distinct stage: it helps define what might be built without itself establishing an operating asset or a completed financing package.
For prospective buyers, increased module output can change how a proposed plant fits their electricity needs. The effect on actual power cost still depends on construction, financing, operations and the eventual contract. Neither the module rating nor the approval supplied a delivered electricity price.
May’s result was therefore useful and bounded. Developers could advance applications around a larger, reviewed NuScale design. Turning that design into dependable electricity would require the remaining permits, investment and physical execution to follow.
Sources
- NRC Approves Standard Design for NuScale US460 Small Modular Reactor — Nuclear Regulatory Commission · 2025-05-29.
- NRC Approves NuScale Power’s Uprated Small Modular Reactor Design — U.S. Department of Energy · 2025-05-30.
- NuScale Power’s SMR achieves standard design approval for 77 MWe — NuScale Power / U.S. Securities and Exchange Commission · 2025-05-29.