Simulation of the CRUD formation process using the Lattice Boltzmann Method

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 LiBO₂ and nickel-boroferrite Ni₂FeBO₅ (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 Fe³+ ion concentration.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Nuclear, Plasma, Radiolgc Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2012

Author dc:creator

• Li, Zebo

Contributors dc:contributor

• Uddin, Rizwan

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

Statement dc:rights

• Copyright 2011 Zebo Li

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/29727

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/29727