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DOE OSTI · 3394710

Phenomena Identification and Ranking Tables for High Temperature Gas-Cooled Microreactors

Bindra, Hitesh [Purdue Univ., West Lafayette, IN (United States)]·Gougar, Hans [X-Energy, LLC, Rockville, MD (United States)]·Schunert, Sebastian [Radiant Nuclear, Idaho Falls, ID (United States)]·Windes, William E [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0000000188030885)·Matulis, John [Purdue Univ., West Lafayette, IN (United States)]·Sieh, Broderick [Purdue Univ., West Lafayette, IN (United States)]·Kawaji, Masahiro [City College of New York, NY (United States)]·Kalaga, Dinesh [City College of New York, NY (United States)]·Sabharwall, Piyush [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:000000032567205X)·Hassan, Yassin [Texas A&M Univ., Kingsville, TX (United States)]·Bajorek, Stephen [US Nuclear Regulatory Commission (NRC), Washington, DC (United States)]·Gutowska, Izabela [Oregon State Univ., Corvallis, OR (United States)]·Brooks, Caleb [Univ. of Illinois at Urbana-Champaign, IL (United States)]·Lou, Xiaoyuan [Purdue Univ., West Lafayette, IN (United States)]·Reger, David Alan [Idaho National Laboratory (INL), Idaho Falls, ID (United States)]·Thome, Ted [BWX Technologies, Lynchburg, VA (United States)]·Owston, Becky [BWX Technologies, Lynchburg, VA (United States)]·Strydom, Gerhard [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0000000257128553)·McEligot, Donald M [Idaho National Laboratory (INL), Idaho Falls, ID (United States)]·Schultz, Richard [Idaho State Univ., Pocatello, ID (United States)]·Yilgor, Ilyas [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0000000169986662)
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Abstract

Micro-scaled high-temperature gas-cooled reactors (micro-HTGRs) offer a promising option for reliable power in remote or off-grid locations. While the safety characteristics of modular HTGRs have been widely studied, a micro-HTGR configuration alters several key thermal-fluid phenomena that govern both normal operation and passive decay-heat removal. In many proposed concepts, the reactor vessel is oriented horizontally and integrated into an ISO shipping container to enhance transportability and modular deployment. This report documents a Phenomena Identification and Ranking Table (PIRT) exercise focused on the thermal hydraulic safety phenomena relevant to all micro-HTGRs. The objective is to systematically identify, describe, and rank the importance, uncertainty, and modeling complexity of the key phenomena that control core and vessel temperatures during normal operation, pressurized conduction cooldown (PCC), and depressurized conduction cooldown (with air ingress) conditions.

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22 - GENERAL STUDIES OF NUCLEAR REACTORS22 GENERAL STUDIES OF NUCLEAR REACTORS42 - ENGINEERING42 ENGINEERING99 - GENERAL AND MISCELLANEOUS99 GENERAL AND MISCELLANEOUSAdvanced ReactorsHigh Temperature Gas-Cooled ReactorsHorizontalMicroreactorsPhenomena Identification And Ranking TablePIRTThermal HydraulicsVertical

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Bindra, Hitesh [Purdue Univ., West Lafayette, IN (United States)], Gougar, Hans [X-Energy, LLC, Rockville, MD (United States)], Schunert, Sebastian [Radiant Nuclear, Idaho Falls, ID (United States)], Windes, William E [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0000000188030885), Matulis, John [Purdue Univ., West Lafayette, IN (United States)], Sieh, Broderick [Purdue Univ., West Lafayette, IN (United States)], Kawaji, Masahiro [City College of New York, NY (United States)], Kalaga, Dinesh [City College of New York, NY (United States)], Sabharwall, Piyush [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:000000032567205X), Hassan, Yassin [Texas A&M Univ., Kingsville, TX (United States)], Bajorek, Stephen [US Nuclear Regulatory Commission (NRC), Washington, DC (United States)], Gutowska, Izabela [Oregon State Univ., Corvallis, OR (United States)], Brooks, Caleb [Univ. of Illinois at Urbana-Champaign, IL (United States)], Lou, Xiaoyuan [Purdue Univ., West Lafayette, IN (United States)], Reger, David Alan [Idaho National Laboratory (INL), Idaho Falls, ID (United States)], Thome, Ted [BWX Technologies, Lynchburg, VA (United States)], Owston, Becky [BWX Technologies, Lynchburg, VA (United States)], Strydom, Gerhard [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0000000257128553), McEligot, Donald M [Idaho National Laboratory (INL), Idaho Falls, ID (United States)], Schultz, Richard [Idaho State Univ., Pocatello, ID (United States)], Yilgor, Ilyas [Idaho National Laboratory (INL), Idaho Falls, ID (United States)] (ORCID:0000000169986662). 2026-07-30. Phenomena Identification and Ranking Tables for High Temperature Gas-Cooled Microreactors. https://doi.org/10.2172/3394710

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