Icone11-36571 Study of Solid Moderators for the Thermal-Spectrum Supercritical Water-Cooled Reactor (Neutronics)

A Solid Moderator Physics Assessment for the Canadian SCWR

“…Significant reductions in the cycle length, as achieved by previous work on the Canadian SCWR [1], due to perturbations in the concept would render the proposed perturbations nonviable. An earlier study by Buongiorno and MacDonald [6] has shown that zirconium hydride is the best candidate for a solid moderating material in SWCR conditions, as it most mimics the moderating behavior of light water. A number of possible solid moderators were investigated including beryllium, beryllium oxide, carbon, silicon carbide, and zirconium hydride [6].…”

“…An earlier study by Buongiorno and MacDonald [6] has shown that zirconium hydride is the best candidate for a solid moderating material in SWCR conditions, as it most mimics the moderating behavior of light water. A number of possible solid moderators were investigated including beryllium, beryllium oxide, carbon, silicon carbide, and zirconium hydride [6]. The study concluded that zirconium hydride was the only viable option from a reactor physics perspective for use in a thermal spectrum SCWR as the other solid moderators failed to provide sufficient moderation [6].…”

“…A number of possible solid moderators were investigated including beryllium, beryllium oxide, carbon, silicon carbide, and zirconium hydride [6]. The study concluded that zirconium hydride was the only viable option from a reactor physics perspective for use in a thermal spectrum SCWR as the other solid moderators failed to provide sufficient moderation [6]. Therefore, zirconium hydride has been selected in this study based primarily on the Buongiorno and MacDonald study [6] and additionally on its merits in other applications.…”

“…The study concluded that zirconium hydride was the only viable option from a reactor physics perspective for use in a thermal spectrum SCWR as the other solid moderators failed to provide sufficient moderation [6]. Therefore, zirconium hydride has been selected in this study based primarily on the Buongiorno and MacDonald study [6] and additionally on its merits in other applications. Other applications include the Japanese SCWR concept, which employs the use of zirconium hydride as a solid moderator in their fast spectrum reactor option [7]; MOX-fuelled fast reactors [8]; and lastly, it has been in use in TRIGA type reactors for decades [9].…”

“…As there will likely be hydrogen released from the solid moderator, this will provide a means of hydrogen gas interacting with the flow tube clad. Further study is required to evaluate the estimated concentration of hydrogen gas and the potential effects of hydrogen embrittlement from a materials perspective, though this issue can also potentially be mitigated with hydrogen impermeable coatings such as molybdenum [6].…”