Analysis of attractiveness of nuclear materials as applied to the on-site fuel cycle of inherently safe fast reactors

As of the present moment a fairly well-established concept of “attractiveness of nuclear materials” is widely used in scientific publications. This term implies that nuclear materials which are involved in the civil fuel cycle may be used for fabricating primitive nuclear explosive devices or even nuclear weapons. This concept serves as an instrument for comparative analysis of various nuclear materials as pertains to their possible diversion for unauthorized application. Attractiveness of nuclear materials is determined in the first place by the neutronics properties inherent to these materials. These properties include the capability of the material under examination to initiate self-sustained chain reaction because otherwise this material will be absolutely unattractive for the above-mentioned purposes. Besides that, the main properties and important characteristics of nuclear materials influencing their attractiveness are the intrinsic neutron background and heat release. The present paper presents the analysis of fuel compositions involved in the fuel cycle of inherently safe BR-1200 fast reactors (BREST-1200) incorporating on-site NFC infrastructure in terms of their attractiveness. The object of investigation are the elementary systems in the form of spheres containing nuclear materials of the BR-1200 fast reactor fuel cycle both without neutron reflectors and surrounded with such reflectors made of different materials. Here, critical conditions are defined for each system for which the main properties characterizing the attractiveness of nuclear materials are calculated taking into account the reflector material and thicknesses.