Modeling and comparative analysis of changeover of homogeneous and heterogeneous core of BN-1200 reactor to equilibrium mode

• Published in: Nuclear engineering and design Vol. 386; p. 111549
• Main Authors: Rodina, E.A., Egorov, A.V., Rachkov, V.I., Khomiakov, Iu.S.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2022; Elsevier BV
• Subjects: Breeding; Closed nuclear fuel cycle; Comparative analysis; Core design; Cycle ratio; Equilibrium; Fast nuclear reactors; Fuel cycles; Heterogeneity; Homogeneous and heterogeneous burning; Innovative fast neutron reactor; Life cycle simulation; Minor actinides; Modelling; Nitride mixed fuel; Nuclear energy; Nuclear fuels; Plutonium; Reactivity; Reactor cores; Reactors; Sodium coolant; Software package; Spent nuclear fuels; Thermal reactors; Virtual reality; Closed nuclear fuel cycle; Innovative fast neutron reactor; Sodium coolant; Minor actinides; Software package; Nitride mixed fuel; Core design; Life cycle simulation; Homogeneous and heterogeneous burning
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2021.111549

•Closed fuel cycle is one of the key features developed within the framework of «Proryv» project in Russian Federation.•Equilibrium reactor core is characterized by the stable reactivity isotopic composition of recycled plutonium.•Analytical studies have been made on sodium cooled large size reactor (1200 MW). Equilibrium reactor core operating in closed fuel cycle with breeding ratio close to 1 is one of the key features of reactor designs developed within the framework of «Proryv» project direction (PD). Equilibrium reactor core is characterized by the stable reactivity and power density pattern, as well as isotopic composition of recycled plutonium. When putting into operation fast reactor using plutonium extracted from thermal reactor spent fuel in bicomponent nuclear power, the reactor core would operate rather long (more than 10 years) in transient mode, which requires special studies and special measures for controlling reactivity coast down during reactor run. Virtual-digital modeling of fast reactor (FR) fuel cycle closure is an efficient tool in such study. In this paper, RTM-2 code package option is outlined and used. This option includes updated fuel cycle model allowing to simulate heterogeneous core layout, as well as to use radial and axial blankets. Analytical studies have been made on sodium cooled large size reactor (1200 MW). Reactivity stabilization in such reactor is slightly more difficult as compared to lead cooled reactors, and excess reactivity exceeds βeff value attributed to BREST type reactors. Owing to heterogeneity of the core, the required excess reactivity can be decreased in transient mode down to βeff level. In equilibrium mode of such core, its breeding ratio (BR) is overrated, and this would even cause reactivity increase (although relatively small). Fuel breeding can be used for assurance of equilibrium mode with high fuel burnup. Basically, there is no need to use blankets in the core designs under consideration. However, one should not discount the demand for fuel breeding, which is also one of the potential advantages of fast reactors. Modeling has shown the possibility of adaptable variation of BR of BN-1200 M reactor within the range of values from 1.05 to about 1.4 with the use of additional blankets (axial and radial) and enriched N15.