Physical and numerical problems of computerized simulation of coolant mixing in the primary circuit of a nuclear reactor. Literature survey. Rev. 1

The problems are related to the following topics: effect of low-boric-acid coolant entering the reactor core on reactivity, and the appearance and consequences of pressurized thermal shocks due to the injection of the cold coolant into the primary circuit. The main physical processes occurring during the mixing of coolants with different densities or concentrations in the primary circuit and some approximate mathematical models are described, and numerical problems appearing during the process of solving the applicable partial differential equations are discussed and some ways to eliminate them are indicated. (P.A.)