Decomposition of the Mathematical Model of Precision Neutron-Physical Calculations of Nuclear Reactors

Abstract

The main goal of the work is to assess the possibility of minimizing the design time of nuclear reactors. The achievement of the goal is facilitated by the development of hierarchical models of neutron-physical calculation of the reactor. The models assume the use of a single software package, which eliminates errors associated with the inconsistency of mathematical models used at different levels. The work uses the well-known MCU code, developed by specialists of the NRC “Kurchatov Institute” and the author’s codes. To analyze the void reactivity effect in fast reactors with a traditional geometric shape of the core, a two-level model is used. For studies of a strip zone reactor, an intermediate level of hierarchy is required: a three-level model is used. The subsystem of the lower level is characterized by the minimum time spent on calculations. It allows you to estimate the exact upper bound of the void reactivity effect. Thus, at the stage of preparing a technical proposal, it is possible to limit ourselves to using only the lower-level model, which will reduce the research time by an order of magnitude. This model made it possible to quickly solve a number of practical problems. The significance of research is determined by the possibility of easy adaptation of the model to reactors of different types and to use as the base code of any software package for precision neutron-physical calculation of the reactor. There is no need to use a third-level subsystem to analyze the void reactivity effect in reactors with an unconventional core or low-power reactors. The subsystem gives highly overestimated void effect results. The proposed models are used for post-optimization analysis, computational experiment, and parameterization procedures.