Core Flow Distribution For The 2MW Thorium Molten Slat Reactor With Liquid Fuel

Molten Salt Reactor(MSR) is one of six generation IV reactor types, which uses liquid molten salt as the coolant and fuel solvent. It has several outstanding advantages: inherent safety, neutron economy, nuclear fuel cycle, miniaturization,online processing, efficiently use of nuclear resources and non-proliferation attributes,etc. The Strategic Priority Program of the Chinese Academy of Sciences-Thorium Molten Salt Reactor(TMSR) Nuclear Energy System has been lunched by Chinese Academy of Science in 2011.One target of TMSR Nuclear Energy System is completing the 2MW Thorium Molten Salt Reactor with liquid fuel(TMSR-LF1).Mass and momentum of molten salt fluid could not exchange between contiguous channels due to the fuel channels of TMSR-LF1 are closed loop channel.In the thermal hydraulics design of reactor, the reactor core inlet flow distribution and pressure distribution are determined according to the condition of the coolant channel's inlet and outlet temperature, mass flow rate, inlet pressure. The temperature distribution of coolant channels are computed on the basis of power distribution at the radial and axial direction in reactor core. In the thermal hydraulics design of TMSR-LF1, the mass flow rate distribution of core inlet match with the release heat distribution. In order to achieve core power distribution flattened in radial, the method were adopted that coolant mass flow rate is not the same in different core regions at radial direction. As a result, molten salt fluid of upper plenum is mixing homogenized,what's more, layered flow of the molten salt fluid and hot spot drafting are avoided.2MW TMSR-LF1 was the study object in this paper, and Solidworks2014 was used to build the 3D geometry of TMSR-LF1. ANSYS Fluent to be used as a primary tool. The research focus on the structure of upper and lower plenum, as well as the flow distribution device in the lower plenum, which play a decisive role for the core flow distribution.It verified that changing the structure of lower plenum and setting the flow distribution device can optimize core flow distribution is feasibility on a 1/4 model of TMSR-LF1 reactor. On the integrated model of TMSR-LF1, many scheme'snumerical simulation results were analyzed and compared, which including the height of standard ellipsoid halved and changing the structure of lower plenum to flared, as well as, setting different kinds of flow distribution device in lower plenum. The flow distribution device has a cylindrical, rectangular-shaped, hemispherical, bowl-shaped,Barrel-shaped, combination-shaped. It determined the optimization core flow distribution scheme according to the numerical simulation results. The scheme are the height of standard ellipsoid halved and changing the structure of lower plenum to flared, in addition to selected the barrel-shaped and combination-shaped flow distribution. Three scheme were selected to compare the temperature distribution's symmetry of molten salt channels' outlet section.The research indicated that changing the structure of upper plenum can eliminate the stagnant flow region effectively and suppress the vortex flow. The flow field distribution was optimized and molten salt fluid was mixed homogeneous. The purpose of molten salt channels' mass flow distribution homogeneous and the core power distribution can be flattened in radical. The research results can provide a reference for the core structure optimization design of TMSR-LF1.