Дослідження методом кластерної динаміки впливу зміни температури на нейтронну крихкість α-заліза

Abstract

Метод кластерної динаміки використовується для моделювання впливу температури на зростання межі текучості, яке зумовлено нейтронним опромінюванням. Показана необхідність врахування зміни температури при використанні даних про нейтронну крихкість зразків-свідків для оцінки механічних властивостей корпусу атомного реактору при робочій температурі. The actual issue of using data of neutron embrittlement of reactor materials received under the study of witness-samples, installed at selected points of the atomic reactor, to the assessment of the actual neutron embrittlement of the reactor is considered. Significant difference in the mechanical properties, including neutron embrittlement, of the predicted values based on the results of examination of witness-samples and the results of examinations of the reactor pressure vessel of the nuclear power plant Graiswald (Germany) after its closure in 1990, was found experimentally in 2010-2013 years. Here, the mechanical properties have been measured and the small-angle neutron scattering method has been used to determine the size and density of nanodefects with a size of up to 3 nm, namely clusters of point defects (vacancy clusters and clusters of interstitial atoms), copper precipitates, and clusters composed of point defects and alloying elements of the reactor pressure vessel steel. In the proposed study, one of the possible causes of the mentioned discrepancy is considered, namely, the difference in the surveillance temperature of the reactor (300 °C) and the temperature of the witness-sample (123 °C), which is irradiated for about one year in the reactor, and then extracted from it during routine shutdowns, for example, when replacing nuclear fuel. In order to simplify, we study the effect of temperature change not on reactor steel, but on commercial pure-iron (carbon content is less than 30 ppm).