Establishing a relation between the energy parameters of the research impulse graphite reactor and the tested fuel assembly with a block structure

Abstract

Establishing a connection between the parameters of the fuel assembly (FA) tested at the research reactor and the parameters of the reactor itself is an important step in the procedure for preparing demonstration experiments, the purpose of which is to obtain a set of data on the processes occurring in the core of a nuclear reactor in transient and emergency modes. To set up the research reactor operating mode in a demonstration experiment, it is necessary to know reliably the ratio between the power in the reactor and in the tested FA. In this article, as part of the development of the methodology for the preparation and conduct of reactor tests at Impulse Graphite Reactor (IGR), three independent methods for determining the energy parameters of reactor test facilities with the FA having a block structure have been considered and tested in a series of three calibration reactor experiments and a set of computational studies. The ratio of specific power density in the FA and at the IGR has been determined by the thermal balance method based on the results of measuring the temperature of the structural elements, the gamma spectrometric method based on measurements of the content of fission products in the fuel composition after irradiation, and theoretical computational studies based on the use of computer modeling tools. The resulting ratio value is in the range of (7.73 … 7.78)⋅10⁻⁷ (kJ/g(UO₂))/kJ_IGR. The results of the application of three independent methods are in good agreement with each other, which indicates the absence of contradictions between them and the possibility of using them in the preparation and implementation of experimental testing programs for the reactor fuel at the research.