Chemical processing blanket power

While chemical processing sharply discontinues the growth of in the blanket, the power level in the blanket may markedly overshoot the equilibrium level, as shown in P ig. 2-15(b). An overshoot is obtained when the blankeUU concentration reaches its maximum value before core processing starts. Table 2-14 shows the peak values of blanket power computed for the reactors studied, along with the equilibrium values. 

Results similar to tho.se given above have also been obtained [33] for two-region breeders having various concentrations of thorium in the core. The core diameter was set at 4 ft, the pressure-vessel diameter at 9 ft, and the blanket thorium concentration at 1000 g Th/liter. The core thorium concentrations studied were 100, 150, and 200 g Th/liter. As before, the moderator was heavy water in both core and blanket volumes, and both regions operated at a mean temperature of 280°C the Zircaloy-2 core tank was 0.33 in. thick. Calculations were performed at a constant total power of 60 thermal Mw. The same chemical processing conditions were assumed... 

An economic amxlysis of the effects of changing the blanket power fraction was performed to determine the optimum core-blanket power split under e( uilil)rium operating conditions. The parameters affecting this choice are (1) fission-product poison levels in the blanket, (2) fission-product poison levels in the core, and (3) chemical processing costs. 

Fig. 24-10. Chemical processing cycles vs. blanket power, based on a blanketed sphere with total reactor power of 825 Mw and the removal efficiencies of = 0.25, 13 0.04, — 0.10, Zpp — 1.00.

In tlie PUREX process, the spent fuel and blanket materials are dissolved in nitric acid to form nitrates of plutonium and uranium. These are separated chemically from the other fission products, including the highly radioactive actinides, and then the two nitrates are separated into tv/o streams of partially purified plutonium and uranium. Additional processing will yield whatever purity of the two elements is desired. The process yields purified plutonium, purified uranium, and high-level wastes. See also Radioactive Wastes in the entry1 on Nuclear Power Technology. Because of the yield of purified plutonium, the PUREX process is most undesirable from a nuclear weapons proliferation standpoint,... 

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