Assessing the Impact of Effective Thermal Conductivity on Gas-Cooled Reactor Transients in RELAP5-3D

Robert F. Kile, Aaron S. Epiney, Nicholas R. Brown

Research output: Contribution to journalConference articlepeer-review

Abstract

High-temperature gas-cooled reactors (HTGRs) are a relatively mature advanced reactor concept that are of interest to industry and government for near-term deployment. These systems feature passive safety through low power density, coated particle fuels, and large graphite volumes that lead to slow heatup. In loss of flow transients, cooldown is achieved through conduction and radiation heat transfer. In prismatic block-type reactors, such as the mHTGR-350, the presence of coolant holes and fuel compacts alters the flow of heat through the blocks. To capture this effect in systems codes like RELAP5-3D, relationships for effective thermal conductivity (ETC) must be used to appropriately degrade the thermal conductivity. This work presents an assessment of the impact of ETC on performance of block-type gas-cooled reactors in a pressurized conduction cooldown (PCC) and depressurized conduction cooldown (DCC) transients. Models for PCC and DCC with bulk material thermal conductivity and ETC were run for both the mHTGR-350 and the High-Temperature Test Facility (HTTF) to determine the impact of ETC on transient performance.
Original languageEnglish
Pages (from-to)747-750
Number of pages4
JournalTransactions of the American Nuclear Society
Volume127
Issue number1
Early online dateNov 17 2022
DOIs
StatePublished - Nov 22 2022
Event2022 Transactions of the American Nuclear Society Winter Meeting and Technology Expo, ANS 2022 - Phoenix, United States
Duration: Nov 13 2022Nov 17 2022

INL Publication Number

  • INL/CON-22-69965
  • 143395

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