Westinghouse asks the U.S. nuclear regulator to treat its small reactor as a smaller AP1000

Westinghouse is asking the U.S. Nuclear Regulatory Commission to treat its new small modular reactor as a scaled-down AP1000 rather than a clean-sheet design. The AP1000 is the 1-gigawatt design already operating in China and forming the spine of the U.S. deployment pipeline.

The vehicle is a set of collaboration agreements with Amentum, the engineering and federal-services contractor spun out of AECOM in 2020. Amentum is not a customer buying reactors. Its role covers two tracks: AP300 design certification and early site licensing at the NRC, and engineering and project-execution support for AP1000 units as Westinghouse scales deployment. Amentum CEO John Heller tied the work to "powering the growth of AI and other energy critical industries" and to firm baseload demand (Westinghouse and Amentum sign AP1000/AP300 collaboration agreements).

The AP300 was unveiled in 2023 as a one-loop derivative of the AP1000, intended to inherit fuel design, steam generators, and the operating record of the larger plant. Westinghouse has set a target of NRC design certification by 2027, then roughly three years of site-specific licensing and three years of construction, implying first power about a decade from launch. The target unit cost is around USD1 billion, and the company says the plant fits in roughly a quarter of a soccer pitch. None of those dates or numbers are NRC-confirmed; they are company targets, and the regulator's clock is the only one that will set the real timeline. The AP300 sits in an NRC pre-application review that has not yet produced a design-certification schedule, and the SMR Intel NRC approval tracker currently shows no SMR with a completed design certification.

Westinghouse calls the combined AP1000 and AP300 strategy the "APX" platform. The logic is that the same fuel, the same major-equipment suppliers, and the same operating procedures carry across both sizes, so a customer that needs 1 gigawatt orders an AP1000 and a customer that needs 300 megawatts orders an AP300, and Westinghouse runs one supply chain. The deal lands the same week Westinghouse filed a draft registration statement for a potential initial public offering, putting the platform in front of public-market investors. Cameco owns 49 percent and Brookfield 51 percent of Westinghouse after the 2023 acquisition that valued the business at about USD8 billion in enterprise value.

The pipeline the IPO disclosure leans on is large on paper. Cameco, in the Amentum announcement, cited 91 potential AP1000 deployments totalling about 105 gigawatts-electric across Westinghouse's markets. In the United States that includes up to 10 reactors funded through DOE American Nuclear Supply Chain Loans in the mid-2030s, up to 10 more through a Cameco/Brookfield/U.S. Commerce Department partnership announced in 2025 for the mid-to-late 2030s, and the resumption of the two-unit VC Summer project in the early-to-mid 2030s. A stated pipeline of 91 opportunities is not a contracted backlog, and the DOE's USD17.5 billion loan commitment is conditional and undrawn, gated by USD500 million of Westinghouse equity and USD500 million of utility-partner equity per project before any federal funds flow.

The small modular reactor segment's most-watched U.S. project, the NuScale-UAMPS six-reactor plan in Idaho, was cancelled in late 2023 after cost estimates roughly doubled. The AP300 is a different design from a different company, but that cancellation reset investor and utility expectations about how fast an SMR moves from announcement to first concrete, and any cold reader weighing this deal is weighing it against that record.

The first test is the NRC. The agency has to accept the inheritance argument for the timeline to hold. Beyond that, the long-lead forging and casting supply chain has to scale in time for first-of-a-kind construction, and the equity gating on DOE loans has to clear for at least one U.S. project site. The next concrete milestone is the design-certification response, which Westinghouse is targeting for 2027.