Software conversion of data for full-scale RBMK calculation with MCU

Software that converts data for precision calculations of an actual state of the RBMK-1000 reactor taking account the configuration, thermohydraulic characteristics, fuel burnup and position of the control rods in the initial data for the MCU software complex is described. The C++ language is used. In the software, the typical elements of the RMBK-1000 (prototypes) core structure are described in the input language of the geometric module of the MCU package (NCGSIM). Together with the files containing libraries of the isotopic composition of the fuel, they make it possible to describe the reactor core in working, heated and cooled states in the language of the initial data for the MCU package. Up to now, the rapid development of computer technology has made it possible to perform full-scale calculations of reactors, including RBMK-1000, with the help of not only engineering but also high-precision computer programs. The MCU complex package based on the Monte Carlo method with a universal description of the core geometry, arbitrary level of accuracy and an evaluated nuclear data library, which makes it possible to take account of the fuel burnup, the position of the rods of the control-and-protection system (CPS) and the thermohydraulic parameters, is used for high-precision calculations of an actual state of different types of reactors [1]. A description of an actual state of the RBMK reactor requires 4‐150 Mb of information depending on the accuracy of the model. The initial data describing the state of the reactor core serve as the source of a portion of this information: load composition, fuel burnup, position of the rods of the control-and-protection systems, temperature of the fuel, coolant and moderator and others. Some of these data are transferred from the reactor control system; the geometric characteristics and the composition of the elements of the core design are represented, as a rule, in the form of blueprints with the standard specification. The fuel characteristics, which vary during the operation of the reactor (material composition), are formed on the basis of data on the three-dimensional distribution of the burnup and preliminary calculations performed using the MCU code with modeling of the variation of the nuclide composition in the burnup regime. The program KDMK, characterized by relative universality, was developed to convert this information into the input data in the language used in MCU package. It uses specialized libraries, which are required in order to describe the structural elements of the RBMK core. The internal data structure of the libraries is fixed. The data are stored as text files with a prescribed format and data can be added without changing the program. The program is written in C++ using a hereditary tree of classes, which makes it possible to control the data conversion process. This is important when working with diverse data, and it makes the problem of modifying the program so as to meet user needs easier to solve. The KDMK program is related with a definite class of reactor plants, in this case RBMK. It converts the description of the initial data on the state of the reactor expressed in engineering language into the specialized language of MCU [2].