Development of Models of the Core of a Lead-Cooled Reactor in the Athlet Code

This paper presents the results of thermohydraulic modeling of a lead-cooled reactor, which is based on the design scheme for the ATHLET code, obtained on the basis of open information on the BREST-OD-300 reactor plant. The main goal of the work is to show the influence of detailed modeling of the installation and various models of hydrodynamics in a system of parallel channels on the distribution of coolant parameters in space. The task of this stage of work was to show a step-by-step modeling of one of the options for dividing the in-reactor space into a system of hydraulic channels. The subdivision of the in-core space is based on the type and number of various elements of the core such as: fuel assemblies with fuel, fuel assemblies with regulating devices, reflector unit, etc. This way of modeling the core allows you to see changes in different parts of the reactor plant when calculating transients. Also for this model, two schemes for modeling parallel channels without cross-links between channels and with cross-links have been created. In early works, studies were carried out on the effect of the splitting method on the parameters of the coolant when simulating transients, but the effect of cross-links has not yet been investigated. These schemes will make it possible to carry out the necessary studies and draw a conclusion about the best way to simulate the reactor core in a given partition of the in-reactor space. Earlier results obtained on simpler models showed the efficiency of dividing the inreactor space into a system of hydraulic channels in transient modes. As a result, the partitioning of the incore space allows, in fact, to perform model calculations in 3D representation. These models will make it possible to carry out a number of calculations with various transient modes and justify the use or not use of crosslinks for this type of modeling of reactors with a liquid metal coolant. The main results of the work show the need for further research in the direction of 3D modeling and hydraulics of the in-reactor space for reactors with a liquid metal coolant.

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