Molten-salt reactor blanket salts

A molten-salt reactor system requires structural materials which will effectively resist corrosion by the fluoride salt mixtures utilized in the core and blanket regions. Evaluation tests of various materials in fluoride salt systems have indicated that nickel-base alloys are, in general, superior to other commercial alloys for the containment of these salts under dynamic flow conditions. In order to select the alloy best suited to this application, an extensi e program of corrosion tests was carried out on the available commercial nickel-base alloys, particularly Inconel, which typifies the chromium-containing alloys, and Hastclloy B, which is representative of the molybdenum-containing alloys. 

The AHTR appears to have excellent safety attributes. The combined thermal capacity of the graphite core and the molten salt coolant pool offer a large time buffer to reactor transients. The effective transfer of heat to the reactor vessel increases the effectiveness of the RVACS and DRAGS to remove decay heat, and the excellent fission product retention characteristic of molten salt provides an extra barrier to radioactive releases. The low-pressure, chemically nonreactive coolant also greatly reduces the potential for overpressurization of the reactor containment building and provides an important additional barrier for fission product release. The most important design and safety issue with the AHTR may be the performance and reliability of the thermal blanket system, which must maintain the vessel within an acceptable temperature range. 

D-plan Dry reprocessing of spent fuel and target/blanket salts including not only molten salt but solid fuel of ordinary reactors such as the LWR, fast breeder reactors (FBR), heavy water reactors (HWR), etc. for producing molten fluoride fuel salt of the FUJI or target/blanket salt of the AMSB ... 

Figure 7.7 Influence of the batch reprocessing rate on the breeding ratio in the core and in the whole molten salt fast reactor system (core + fertile blanket).

Ajou University developed AMBIDEXTER-NEC (Advanced Molten-salt Breakeven Inherently-safe Dual-function EXcellenTly-Ecological Reactor Nuclear Energy Complex). The objective of the reactor is to bum DUPlC fuel, minimize minor actinides production, and of course, generate electric power. To achieve the objectives, the AMBIDEXTER reactor core consists of two parts, a blanket and a seed. The blanket consists of only molten salt fuel (LeF-BeF2-(Th,U,Pu)F4), and the seed consists of the molten salt fuel and graphite moderator channel. The blanket area has very hard neutron spectrum, almost looks like fast reactor neutron spectium, and the seed area has a soft neutron spectium almost looks like PWR. Therefore, AMBIDEXTER can achieve low conversion ratio, about 0.298, ie, it is a burner reactor. The code developed to analyze AMBIDEXTER is called AMBIKIN2D. The code system consists of HELIOS, AMDEC, and AMBIKIN2D. 

Fig. 14-4. Initial fuel regeneration in two-region, homogeneous, molten fluoride-salt reactors fueled with U . Total power, 600 Mw (heat) external fuel volume, 339 ft core and blanket salts No. 1.

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