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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Spent fuel transfer project completed at INL
Work crews at Idaho National Laboratory have transferred 40 spent nuclear fuel canisters into long-term storage vaults, the Department of Energy’s Office of Environmental Management has reported.
Apoorva Rudra, Masahiro Kawaji (City College of New York), Aleksandr V. Obabko Saumil Patel (ANL)
Proceedings | Advances in Thermal Hydraulics 2018 | Orlando, FL, November 11-15, 2018 | Pages 694-700
Very High Temperature Reactors (VHTRs) have passive safety systems in comparison to the traditional current generation nuclear reactors that have active safety systems. In addition, they have gaseous coolants like helium proposed for them that allow them to operate at a temperature over 1000 oC along with other applications. However, several substantial engineering challenges are expected in VHTRs and can lead to localized hot spots in the reactor core as a result of degraded heat transfer in coolant channels. Our work addresses one such scenario called flow relaminarization. The following work incorporates 3D simulations in a very long pipe wherein turbulence is sustained throughout for the largest aspect ratio (L/D ratio) known in literature (~235). This work is the first step of a two-step process towards the final objective of studying heat driven turbulent gas relaminarization. Simulations are performed using a high order, spectral element and massively parallel CFD code called NEK5000 that combines the geometric flexibility of finite elements with the high accuracy of spectral methods. A replication method along with recycled periodicity is incorporated to successfully sustain turbulence throughout the pipe. The maximum Reynolds number incorporated for these simulations is 5190 which is chosen keeping in mind the flow relaminarization (forced convection) experiments that were performed by the group in the past. A sensitivity study on the polynomial order was performed as well and based on that the polynomial order chosen for the simulations was 6.