An International Spent Nuclear Fuel Storage Facility Exploring a Russian Site as a Prototype: Proceedings of an International Workshop (2005) / Chapter Skim
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The Use of Sodium-Cooled Fast Reactors for Effectively Reprocessing Plutonium and Minor Actinides
The Use of Sodium-Cooled Fast Reactors for Effectively Reprocessing Plutonium and Minor Actinides
Pages 59-72
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From page 59... ...
To date, studies have been made at the conceptual level regarding various means of using reactor technology to recycle wastes from the nuclear power industry. These studies primarily focus on fast reactors, although VVER-type thermal reactors, for instance, might also be used for the effective reutilization of plutonium.
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From page 60... ...
This report considers various means of using sodium-cooled fast reactors for reprocessing plutonium and minor actinides produced in nuclear power industry operations. THE CONCEPT OF FAST REACTORS AS ACTINIDE BURNERS In analyzing the possible use of BN-type fast reactors1 to recycle wastes from the nuclear power industry, let us highlight two problems: reprocessing of plutonium and reprocessing of minor actinides.
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From page 61... ...
Meanwhile, about 100 kilograms of minor actinides per year could be burned in specialized cores in BN-800-type fast reactors using fuel without uranium-238, replaced instead with an inert matrix. In the long term it may be possible to burn minor actinides more efficiently in subcritical reactors using accelerators (an accelerator-driven system)
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From page 62... ...
O2 MgO Effective fuel density, g/cm3 4.5 Actinide content (Pu, MA) in fresh fuel, g/cm3 1.6 SVRE in core, %k/k ~0 Doppler effect in active zone, %k/k 0.235 Rate of reactivity change, %k/k/month 3.5 Time between reloadings, in months 3.0 Maximum fuel pin linear power Wt/cm 500 TABLE 2 Quantity of Actinides Produced in Spent Fuel from Thermal Reactors, kg/year/GW (electrical)
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From page 63... ...
Table 2 shows the actinide content of the spent fuel from the VVERtype thermal reactors. The dynamics of changes in fuel cycle characteristics have been studied for TABLE 3 Established Isotope Composition of Fresh Fuel for Fast Reactors (kg/t)
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From page 64... ...
RECYCLING MINOR ACTINIDES IN A BN-800-TYPE REACTOR The previously discussed study has shown that by repeatedly recirculating plutonium fuel containing 7 percent minor actinides through the core of a BN800 reactor using fuel without uranium-238, it is possible to burn approximately 36 kilograms of minor actinides per year, thus processing the output of 1.8 VVER-1000 reactors. The amount of minor actinides increases in a stable manner toward a state of equilibrium at the level of about 12 percent.
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From page 65... ...
FAST REACTORS AS BURNERS OPERATING IN THE OPEN FUEL CYCLE In developing cores for fast burner reactors it is essential to select fuel compositions that would ensure the high stability of the spent fuel during its subsequent burial for storage. A number of Japanese researchers have developed a proposal for using highly stable practically insoluble rock-like fuel (ROX fuel)
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From page 66... ...
Special parametric studies showed that the greatest burning in the active zone could be achieved by using fuel based on pure plutonium dioxide (without a matrix)
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From page 67... ...
. In the initial option the inert matrix substantially mitigates the spectrum, and a significant proportion of intermediate neutrons appears, as a result of which the SVRE goes from a positive to a negative value and the Doppler effect increases by almost two orders of magnitude.
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From page 68... ...
. The fuel subassemblies in this model were loaded with common MOX fuel, but part of the fuel subassemblies were replaced with burn subassemblies containing only minor actinides (AmO2 and NpO2)
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From page 69... ...
2. The efficient burning of minor actinides in a strong moderator is accompanied by noticeable flashes of power at the borders of neighboring fuel subassemblies.
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From page 70... ...
This burning is carried out in special burn subassemblies loaded with elements containing zirconium hydride as well as other elements containing minor actinides in an inert matrix. When 84 such burn subassemblies are installed in the expanded core of a BN-800 reactor using oxide fuel, it is possible to burn about 65 kilograms of americium or neptunium per year.
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From page 71... ...
1996. Concept of fast reactors -- plutonium burners and their fuel cycle.
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