Validation and Comparison of HI-STORM Overpack Thermal-Hydraulic Model with MOOSE and NekRS

TL;DR

This paper validates and compares a thermal-hydraulic model of the HI-STORM dry cask overpack using MOOSE and NekRS to enhance accuracy in simulating natural air circulation for spent nuclear fuel storage.

Contribution

It introduces a high-fidelity validation approach for the HI-STORM overpack thermal model using advanced simulation tools MOOSE and NekRS.

Findings

NekRS provides detailed turbulent flow results in complex geometries.

The validation improves the accuracy of the thermal-hydraulic model.

Enhanced model capabilities support safer dry cask storage design.

Abstract

Nuclear power is a significant source of electricity in the United States, but the average U.S. nuclear power plant is around 40 years old. Safe management of spent nuclear fuel (SNF) is a crucial aspect of the back end of the nuclear fuel cycle. SNF dry storage systems are increasingly popular as they represent an effective solution in this area, given the absence of a final disposal system. In particular, the spent fuel cask system (dry cask method) provides a feasible solution for maintaining SNF ($\sim$60 years) prior to the final disposal. The HI-STORM overpack and MPC-32 canister are the primary components of the HI-STORM 100 dry cask storage system. They remove heat from the system via natural circulation with no human intervention required. This characteristic provides passive heat removal while requiring little maintenance in dry cask storage systems. This project aims to validate and compare the capabilities of a thermal model of HI-STORM overpack developed using the Multiphysics Object-Oriented Simulation Environment (MOOSE) based on the author's previous study. MOOSE is an open-source framework developed by Idaho National Laboratory for multiscale, multiphysics simulations. This study will improve the capabilities of the thermal-hydraulic model of the HI-STORM dry cask storage system by producing high-fidelity results for the air circulation in the overpack. Large Eddy Simulations (LES) are performed using the open-source spectral element code NekRS, developed by Argonne National Laboratory (ANL), for simulating transitional and turbulent flows in complex geometries. NekRS will produce high-fidelity results for the HI-STORM overpack to assess the validity of the current thermal-hydraulic model.