Simulation of the CRUD formation process using the Lattice Boltzmann Method

Chalk River Unidentified Deposits (CRUD);CRUD Induced Power Shift (CIPS);formation;deposition;lattice Boltzmann method (LBM)

Li, Zebo ; Uddin ; Rizwan

关键词: Chalk River Unidentified Deposits (CRUD);    CRUD Induced Power Shift (CIPS);    formation;    deposition;    lattice Boltzmann method (LBM);   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/29727/Li_Zebo.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The Axial Offset Anomaly (AOA) is a major impediment to increases in reactor fuel performance preventing PWRs from operating with even more efficient core designs than they are at present. It is a phenomenon where boron compounds such as lithium metaborate LiBO$_2$ and nickel-boroferrite Ni$_2$FeBO$_5$ (known as mineral bonaccordite) concentrate and precipitate during reactor operation in corrosion products deposited on high-duty fuel assemblies at subcooled nucleate boiling conditions and cause the reactor neutron flux and core axial power distribution to deviate from the predicted distribution. The purpose of the present work is to describe the fundamentals in CRUD formation, transport, and deposition, in order to provide a theoretical basis for evaluating and analysing any fuel operational problem due to CRUD deposits. A Lattice Boltzmann Method model is proposed for simulating thermal hydraulic and chemical conditions in the coolant and the formation process of the CRUD. Simulation results show that existence of CRUD in the nuclear reactors, not surprisingly, leads to an increase in the clad temperature. Presence of CRUD also affects the temperature, molecule and ion concentrations, and electrical potential distribution in the coolant. This effect is especially strong near the CRUD surface. In addition, the results imply that the CRUD formation rate increases approximately linearly with the zeta potential (surface charge density), and Fe$^3+$ ion concentration.