Concept of the cascade subcritical molten salt reactor (CSMSR) for harmonization of the nuclear fuel cycle

For solving the problem of closing the nuclear fuel cycle (NFC) it is suggested to develop a new element, reactor-burner of long living radioactive wastes (RW), and integrate it into nuclear power (NP) industry. Cascade subcritical molten salt reactor (CSMSR) is suggested as such reactor-burner. CSMSR combines three ideas: the subcritical scheme of a nuclear reactor, the cascade principle of primary neutrons' multiplication, and molten salt nuclear fuel allowing correction of its composition during operation. The cascade scheme of the subcritical reactor allows to reduce by an order of magnitude the power of the extemal neutron source to the level 2-5 MW, which enables one to use proton cyclotrons and electron accelerators as drivers. According to preliminary calculations the sufficient quantity of excess neutrons per fission are released in CSMSR. It is enough both for reproduction of the nuclear fuel (in the converter regime) and for burning the most dangerous long living RW. CSMSR, in contrast to critical molten salt reactors (MSR), can operate in a regime of burner of actinides without adding plutonium in transmutation zone for providing the neutron balance. In this case one reactor burner with thermal power 1 GW can burn ∼300 kg of actinides per year, and the total power of CSMSR should be several percent of the total NP