Overview of HTTF modelling and benchmark efforts for code V&V for gas-cooled reactor applications

Abstract

Accurate modeling and simulation tools for thermal hydraulics calculations are needed to design and license new advanced reactors including small modular reactors (SMR) and microreactors. Uncertainties in modeling and simulation can have significant safety and economic implications.

The High-Temperature Test Facility (HTTF) at Oregon State University (OSU) is a scaled integral effects experiment designed to investigate transient behavior in high-temperature gas-cooled prismatic-block nuclear reactors. High-quality measurement data is available from the HTTF that is suitable for a thermal hydraulics code validation benchmark for gas-cooled reactor simulations.

This paper summarizes individual HTTF modeling efforts to date for tool validation at Idaho National Laboratory (INL), Argonne National Laboratory (ANL), OSU, and Canadian Nuclear Laboratories (CNL) using system thermal hydraulics codes, computational fluid dynamics (CFD) codes and system-CFD code couplings. Also, the paper introduces the upcoming Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA) HTTF thermal hydraulics benchmark, which will allow better comparisons of results between different international modeling teams. The benchmark will provide well-defined computational problems that include code-to-code comparisons and comparisons to measured data. These problems provide an avenue for quantifying accuracy and identifying sources of uncertainty in thermal hydraulics calculations, including in measured thermophysical properties, as part of validation for gas-cooled reactor simulation tools.