Particle emission from irradiated VVER-1200 fuel with Am burnable absorber

Abstract

For long-term and safe operation of the reactor, nuclear fuel is modified by doping with various homogeneous compounds and heterogeneous inclusions. Such modified fuel has demonstrated satisfactory performance when irradiated at elevated temperatures and high burnup. However, the issues of radiation safety when handling modified fuel remain less studied. Elements of low and medium atomic mass are often targets for (α, n) reactions, so their use as alloying additives, as well as the use of α-emitting additives, can complicate the radiation situation at the stages of the nuclear fuel cycle. In this work, the neutron components of the radiation characteristics of UO2 with Gd2O3 and AmO2 additives were analyzed. Americium has been investigated as a possible alternative to gadolinium. In fuel containing AmO2, the neutron yield is higher compared to Am-free fuel and is formed mainly by (α, n) reactions in AmO2 in fresh fuel and spontaneous fission of 244Cm nuclides in spent fuel. The research was carried out with the aim of developing procedures and regulations for handling new fuel during its manufacture and after irradiation in the reactor. This work contributes to the study of the neutronic and radiation characteristics of Am-containing fuel, which has the potential for use in modern reactors. Calculations were performed using verified computational codes SOURCES-4C and WIMS-D5B.