Dr. Viorel-Ioan Arimescu


Dr. Viorel-Ioan Arimescu Senior Expert at Framatome Inc, Richland site, retired from the company in September 2022, after almost 24 years of R&D and engineering. Ioan started his career in the nuclear field at the Institute for Nuclear Reactors in Romania in 1980; he obtained a PhD from the Bucharest University in 1987 with a thesis on transient CANDU fuel behavior, developing an original code and performing RIA-type transients in the pulsed-core of the on-site TRIGA reactor. Ioan continued to work for CANDU fuel at Chalk River (CRNL, currently CNL) from 1990 until 1999, serving as Leader of the Modeling Group in the Fuel Safety Branch. Main topics during the CRNL tenure included, high burnup degradation of fuel thermal conductivity, upgrades to the CRNL fuel codes ELESIM and ELOCA, coupling fuel and T/H codes for comprehensive analysis of fuel behavior during accidental conditions, etc.

The work portfolio at Framatome included all aspects of fuel and cladding behavior under normal operating and accidental conditions. Regarding fuel, main contributions were related to fission gas release and swelling, chromia-doped fuel modeling and various upgrades to other fuel phenomena. Cladding topics included free-stress irradiation growth of Zr alloys, modeling plastic deformation of Zircaloy-2 after irradiation based on in-house mechanical tests in hot-cells, hydrogen uptake of Zircaloy-2 in BWRs. An integrated project was the development of the realistic methodology for thermal-mechanical fuel rod performance based on a statistical method and using a best-estimate fuel rod code (RODEX4) and accounting for uncertainties to determine margins for design and licensing analyses.

Fuel reliability and BWR operating guidelines to prevent PCI failures was another area of activity; the power ramp performance of LWR fuel was the subject of the 3rd SCIP Modeling Workshop, which Ioan was invited to lead, and the results were communicated at Topfuel 2014 with a numerous international co-authorship. Ioan was also an active member of the NFIR industry-wide research program, resulting in co-authoring of Zirconium Symposium papers on Zr structural material dimensional stability and hydrogen uptake. Ioan has a long list of conference and journal papers; very recently Ioan was the principal investigator of a white paper on the topic of FFRD with support from an industry-wide review panel.

A summary of Ioan’s qualifications encompasses the following topics: fuel and cladding behavior and performance analysis, modelling fuel rod behavior, design review, manufacturing QC/QA, and safety and licensing aspects.