Analysis of Methods and Technologies for Assessing the Composition of the Corium Formed as a Result of the Accident at the Fukushima Daiichi NPP

摘要

This article analyzes methods and technologies for assessing the way of formation, composition, characteristics, and features of corium, i.e., a mixture of nuclear and structural materials of a nuclear reactor core, which formed as a result of an accident that is accompanied by partial or complete melting of the core. The analysis is based on data from studying the corium formed as a result of the accident at the Fukushima Daiichi nuclear power plant, which are in the public domain and are the result of the work of many scientific organizations around the world. The study of corium is a main problem in improving nuclear safety in the future and an objective in developing the successful procedure for eliminating the consequences of the accident at the Fukushima Daiichi nuclear power plant. Without a detailed analysis of the neutron physics, materials science, gravimetric, and other characteristics of the corium and without creation of a corium data set that combines these characteristics, it is impossible to create a full fledged model of the corium in the future and to organize an efficient and safe process for removing nuclear materials from the damaged units of the Fukushima Daiichi nuclear power plant. This study is aimed at combining the existing research results into a data set, which can later be used to simulate the corium using neutron physics codes. The set being created includes data, such as the size, density, and morphology of corium samples and their approximate nuclide composition. The created data set will allow one not only to perform tasks related to increasing the level of safety when accomplishing the procedure for eliminating the consequences of the accident at the Fukushima Daiichi nuclear power plant through simulation but also will serve as a basis for creating an international benchmark for simulating a mixture that contains nuclear materials (NMs).