| Version | Summary | Created by | Modification | Content Size | Created at | Operation |
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| 1 | Camila Xu | -- | 6074 | 2022-11-15 01:32:51 |
A molten salt reactor (MSR) is a class of nuclear fission reactor in which the primary nuclear reactor coolant and/or the fuel is a molten salt mixture. Only two MSRs have ever operated, both research reactors in the United States . The 1950's Aircraft Reactor Experiment was primarily motivated by the compact size that the technique offers, while the 1960's Molten-Salt Reactor Experiment aimed to prove the concept of a nuclear power plant which implements a thorium fuel cycle in a breeder reactor. Increased research into Generation IV reactor designs began to renew interest in the technology, with multiple nations having projects and, as of September 2021, China is on the verge of starting its TMSR-LF1 thorium MSR. MSRs are considered safer than conventional reactors because they operate with fuel already in a molten state, and in event of an emergency, the fuel mixture is designed to drain from the core where it will solidify, preventing the type of nuclear meltdown and associated hydrogen explosions (like what happened in the Fukushima nuclear disaster) that are at risk in conventional (solid-fuel) reactors. They operate at or close to atmospheric pressure, rather than the 75-150 times atmospheric pressure of a typical light-water reactor (LWR), hence reducing the need for large, expensive reactor pressure vessels used in LWRs. Another characteristic of MSRs is that the radioactive fission gases produced are absorbed into the molten salt, as opposed to conventional reactors where the fuel rod tubes must contain the gas. MSR's can also be refueled while operating (essentially online-nuclear reprocessing) while conventional reactors must be shut down for refueling (Heavy water reactors like the CANDU or the Atucha-class PHWRs being a notable exception). A further key characteristic of MSRs is operating temperatures of around 700 °C (1,292 °F), significantly higher than traditional LWRs at around 300 °C (572 °F), providing greater electricity-generation efficiency, the possibility of grid-storage facilities, economical hydrogen production, and, in some cases, process-heat opportunities. Relevant design challenges include the corrosivity of hot salts and the changing chemical composition of the salt as it is transmuted by the neutron flux in the reactor core. MSRs offer multiple advantages over conventional nuclear power plants, although for historical reasons they have not been deployed.