MIT wants to build an add-on 1 MW sub-critical molten salt reactor beside their 6MW light water reactor to avoid 10 years of regulatory approvals

MIT plans a one-megawatt demonstration molten salt reactor. It would be incapable of sustaining a fission reaction on its own, the researchers believe they could avoid building a standalone experimental prototype, which the Nuclear Regulatory Commission generally requires. That site selection and licensing process can take a decade or longer, so the hope is that this approach could cost hundreds of millions of dollars less and take half as much time to build.

The university lab operates a six-megawatt light-water-cooled research reactor on the northwest side of campus, housed within a powder-blue steel and concrete containment building. The proposed “subcritical facility” would be built adjacent to the hexagonal core, taking over a pair of medical irradiation rooms once used for experimental cancer treatments.

It would be about half the size of a typical demonstration reactor and would depend on neutrons generated by the main reactor to instigate the fission chain reaction in its fuel. That means the project would probably require only an amendment to the existing permit on MIT’s reactor, which went online in 1974, says Lin-wen Hu, the principal research scientist at the lab and the proposal’s developer.

Lin-wen Hu, the principal research scientist at the MIT Nuclear Reactor Laboratory, developed the proposal for the “subcritical facility.”