Authors & Affiliations
Scientific and Engineering Centre for Nuclear and Radiation Safety, Moscow, Russia
The original concept of the boiling water reactor core with the reduced moderation of neutrons is proposed, in which a negative void reactivity effect is provided not by increase leakage of neutrons in the axial direction, but by an another physical principle.
Instead of the traditional core flattening, a special heterogeneous arrangement is proposed, in which, along with tight lattice fuel assemblies (fuel rod diameter is 13.5 mm, the distance between the fuel rods is 1.3 mm) containing uranium-plutonium (MOX) fuel, there are fuel assemblies with uranium-thorium fuel (UO2+ThO2) with a small (~1 %) initial content of 233U or 235U and an increased water-fuel ratio (fuel rod diameter is 12.6 mm, the distance between the fuel rods is 2.2 mm). Urani-um-thorium assemblies provide a negative component of the reactivity effect during dehydration of the core.
The results of the calculation of the reactor with a capacity of 3000 MW (t) showed the possibility of achieving a breeding ratio of fuel within 0.96-1.0 with a negative void reactivity effect (-0.2 %).
The main advantages of the proposed concept are a direct-circuit scheme, medium technological parameters close to traditional boiling reactors, allowing the use of available construction materials and equipment.
light-water boiling reactor, tight lattice fuel assembly, fast neutron spectrum, neutronic characteristics
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