NPRE researchers are taking the lead in a $5 million project to fabricate and test modified nuclear reactor cladding.
The goal of the project is to develop an accident tolerant nuclear fuel cladding for commercial power applications.
The U.S. Department of Energy has awarded a Nuclear Energy University Programs grant of $3.5 million for the work to the Nuclear, Plasma, and Radiological Engineering (NPRE) Department at the University of Illinois at Urbana-Champaign to explore advanced nuclear fuel cladding concepts for greater accident tolerance of light water nuclear reactors. The United Kingdom’s Research Council Energy Programme will provide an additional $1.5 million toward collaborative activities directly related to the project, leading to a total investment of $5 million. This international research effort represents a proactive response of the DOE, the U.S. nuclear industry, and the United Kingdom following the March 2011 events in Fukushima, Japan, when an earthquake and tsunami hit the northern part of the country, leading to the eventual destruction of reactors at the Daiichi site.
Lead investigator for the three-year project is NPRE Prof. Brent J. Heuser. Joining him from NPRE will be Department Head James F. Stubbins, Prof. Rizwan Uddin and Assistant Prof. Tomasz Kozlowski. Heuser will lead the work on reactor cladding performance and Kozlowski will take the lead on reactor systems.
Also from Illinois, Materials Science and Engineering Department faculty Associate Prof. Dallas Trinkle and Prof. Robert S. Averback will participate in the work. Fifteen additional principal investigators from the University of Florida, the University of Michigan, Idaho National Laboratory, the University of Manchester in the United Kingdom, and industrial partner ATI Wah Chang, an Albany, Oregon-based nuclear cladding fabricator, will be involved.
Heuser said the scientists will examine two concepts to develop accident tolerance during off-normal event scenarios: 1) the application of a coating to the cladding and 2) bulk composition changes that promote self-healing in the cladding.
Nuclear fuel cladding separates the water coolant and fuel, representing the first engineering barrier for the reactor. The reactor pressure vessel and the reactor containment structure are additional engineering barriers. The material used in cladding is Zircaloy, a zirconium-rich alloy containing small amounts of tin, iron, nickel, and chromium.
In the case of the Fukushima accident, the Zircaloy cladding reacted with steam to form thick oxide scale. This oxidation reaction adds additional heat to the fuel during the transient and releases hydrogen gas.
Heuser and his group believe that applying a coating to the cladding will inhibit oxide formation, thus preventing hydrogen release and additional fuel heating. With the self-healing option, an additive is included in the cladding material. During an off-normal event, the additive will migrate to the surface and form a coating. This change in the surface composition is anticipated to inhibit oxide formation.
The NPRE scientists’ work in this project is related to existing research, also funded by the DOE, to study used nuclear fuel in storage. The new project is anticipated to leverage the technical expertise and facilities at the Urbana campus and the other partner institutions to further promote nuclear reactor safety.
Six new graduate students will be needed within NPRE to participate in the project, Heuser said, with more students supported at the partner academic institutions both in the United States and overseas.