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Abstract ZL187Abstract + Presentation
Internal Fire Probabilistic Risk Assessment for Xe-100 SMR
Internal Fire Probabilistic Risk Assessment for Xe-100 SMR
Zhiping Li, Andy Spotts, Harry Liao, and Luke McSweeney
This paper presents a preliminary internal fire probabilistic risk assessment (PRA) for the Xe-100 small modular reactor (SMR) at the Project Long Mott (PLM) site in Calhoun County, Texas, representing the first site-specific internal fire PRA for this Generation IV pebble bed high-temperature gas-cooled reactor (HTGR) utilizing TRISO fuel embedded in graphite pebbles.
The analysis was developed consistent with ASME/ANS RA-S-1.4-2021 standards for advanced non-light water reactor PRAs, building upon the Xe-100 Version 25 At-Power Internal Events PRA Model (PRA-25). The methodology includes fire ignition frequency analysis using generic data from NUREG-2169 apportioned to site-specific fire areas, and event sequence quantification using Phoenix Architect/CAFTA software with conservative plant response modeling assuming fire-induced total loss of feedwater. A sensitivity case was performed by assuming simultaneous failure of the startup/shutdown system (SSS) and active reactor cavity cooling system (ARCCS) in addition to the total loss of feedwater to assess the resulting challenge to the safety-related passive RCCS.
Key insights include recommendations for spatial separation or fire barriers between redundant feedwater trains to significantly reduce fire-induced total loss of feedwater initiator frequency, independent routing of fail-safe circuits to prevent spurious operations, and addressing instrument air dependency for feedwater control as a potential vulnerability. The analysis recognizes that conservative assumptions due to preliminary design stage likely result in upper-bound risk estimates. This preliminary assessment provides valuable insights for Xe-100 design optimization, identifying areas where fire protection strategies and component separation can enhance plant safety, while demonstrating application of modern PRA standards to advanced reactor designs during the pre-operational phase, with future refinement of cable routing, equipment locations, and fire barrier specifications expected to enable more realistic risk quantification while reducing conservatisms.
Keywords: Internal fire PRA, Xe-100, small modular reactor, HTGR, advanced reactor, ASME/ANS RA-S-1.4-2021
← Check another abstractZhiping Li, Andy Spotts, Harry Liao, and Luke McSweeney
This paper presents a preliminary internal fire probabilistic risk assessment (PRA) for the Xe-100 small modular reactor (SMR) at the Project Long Mott (PLM) site in Calhoun County, Texas, representing the first site-specific internal fire PRA for this Generation IV pebble bed high-temperature gas-cooled reactor (HTGR) utilizing TRISO fuel embedded in graphite pebbles.
The analysis was developed consistent with ASME/ANS RA-S-1.4-2021 standards for advanced non-light water reactor PRAs, building upon the Xe-100 Version 25 At-Power Internal Events PRA Model (PRA-25). The methodology includes fire ignition frequency analysis using generic data from NUREG-2169 apportioned to site-specific fire areas, and event sequence quantification using Phoenix Architect/CAFTA software with conservative plant response modeling assuming fire-induced total loss of feedwater. A sensitivity case was performed by assuming simultaneous failure of the startup/shutdown system (SSS) and active reactor cavity cooling system (ARCCS) in addition to the total loss of feedwater to assess the resulting challenge to the safety-related passive RCCS.
Key insights include recommendations for spatial separation or fire barriers between redundant feedwater trains to significantly reduce fire-induced total loss of feedwater initiator frequency, independent routing of fail-safe circuits to prevent spurious operations, and addressing instrument air dependency for feedwater control as a potential vulnerability. The analysis recognizes that conservative assumptions due to preliminary design stage likely result in upper-bound risk estimates. This preliminary assessment provides valuable insights for Xe-100 design optimization, identifying areas where fire protection strategies and component separation can enhance plant safety, while demonstrating application of modern PRA standards to advanced reactor designs during the pre-operational phase, with future refinement of cable routing, equipment locations, and fire barrier specifications expected to enable more realistic risk quantification while reducing conservatisms.
Keywords: Internal fire PRA, Xe-100, small modular reactor, HTGR, advanced reactor, ASME/ANS RA-S-1.4-2021