New York-based Terrestrial Energy USA announced on 24 January that it had informed the US Nuclear Regulatory Commission (NRC) of plans to license a small modular reactor (SMR). Terrestrial said it intends to start "pre-application interactions" with NRC this year and to make its licensing application in late 2019.

NRC recently published a letter from Terrestrial responding to the agency's Regulatory Issue Summary (RIS) published on 7 June last year. An RIS is an NRC request for information regarding future nuclear reactor licence filings.

In its letter in November 2016, Terrestrial  included the status of the design, analyses, testing, licensing, and project planning for its Integral Molten Salt Reactor (IMSR), which is a liquid-fuelled, high-temperature, 400MWt advanced reactor power plant design. NRC is developing a specific licensing framework for advanced reactor designs, Terrestrial noted, adding it has "confidence in the capability" of the regulator to review and reach safety, security, and environmental findings on the IMSR design, "in a timely manner".

Terrestrial is examining four sites for its first commercial plant, which include the Idaho National Laboratory (INL) and additional sites east of the Mississippi River. Terrestrial says the IMSR "extends the applicability of nuclear energy far beyond its current footprint in on-grid electric power markets" and "promises to increase industrial competitiveness and energy security while concurrently driving deep and rapid decarbonisation by displacing fossil fuel combustion across a broad industrial front".

Last year, Terrestrial Energy USA's parent, Canada's Terrestrial Energy Inc, announced its plans to engage with the Canadian Nuclear Safety Commission in a pre-licensing design review, a first step towards an eventual licence application.