Radiation-thermal changes in serpentinite concretes of “dry” shield of Water-Water Energetic Reactors of NPP during extension of their operation
Abstract
Radiation-thermal changes in serpentinite concretes of “dry” shield of Water-Water Energetic Reactors of NPP during extension of their operation
Incoming article date: 15.02.2024Calculation and analytical studies have been carried out on the influence of the duration of operation of nuclear power plants (NPP) when extending their service life on radiation and radiation-thermal changes of volume and compressive strength in serpentinite concrete of “dry” radiation-thermal shield (hereinafter referred to as “dry” shield) of Water-Water Energetic Reactors (WWER /VVER) different power. Concrete based on typical serpentinite aggregate from the Bazhenov deposit, used for the production for concrete of “dry” shield, is considered. It has been established that with increasing operating duration, radiation changes of the serpentinite concretes in “dry” shield of NPPs with VVER will generally increase monotonically and, in terms of volume changes, can become commensurate with or even exceed permissible values. In this regard, radiation changes in the concrete of «dry» shield should be taken into account when extending the operating life of nuclear power plants. It has been shown that radiation changes in the concrete of “dry” shield for NPPs with VVER-440 are 2 - 4 times more significant than of “dry” shield concrete for NPPs with VVER-1000. Radiation changes in the concrete of "dry" shield increase with decreasing average operating temperature. Thermal changes in serpentinite concretes of "dry" shield when exposed to operational and emergency temperatures increase with temperature and make a significant contribution to radiation-thermal changes in dry-shield concretes. The results obtained can be used to establish the permissible period for extending the operation of nuclear power plants with reactors of the VVER 440 and VVER-1000 types based on radiation-thermal changes in serpentinite concrete of "dry" shield.
Keywords: radiation, thermal, radiation-thermal changes, serpentinite concrete, “dry” radiation-thermal shield, water-water energetic reactors, extension of the operating life of NPP