Idaho National Laboratory, ID

Idaho National Laboratory, Advanced Test Reactor (INL ATR) SPRA


The Department of Energy uses the Advanced Test Reactor (ATR) at Idaho National Laboratory to test nuclear fuel systems and materials. The light-water moderated and cooled reactor has a four-leaf clover design that allows for a variety of testing options. The structures, systems, and components (SSCs) essential to plant safety include coolant system piping, pumps and heat exchangers, diesel generators, switchgear, transformers, control panels, batteries, battery chargers, and instrumentation. The majority of the SSCs are contained in the TRA-670 building, which consists of a reinforced concrete substructure and steel superstructure. In response to evolving seismic criteria and knowledge, Battelle Energy Alliance decided to update the 1991 seismic probabilistic risk assessment (SPRA) of the ATR and SGH developed seismic fragilities in support of the new SPRA.

SGH developed seismic fragilities of risk-significant SSCs, which constitute one of the key inputs to the SPRA. For this project, we:

  • Implemented an efficient approach to utilize existing seismic qualification data for Performance Category 4 (PC-4) criteria
  • Supported development of the PRA Components List
  • Conducted seismic walkdowns of SSCs that were not seismically qualified following DOE/EH-0545 procedures
  • Screened SSCs that satisfied PC-4 seismic criteria from detailed fragility evaluation
  • Developed seismic fragilities for selected risk-significant SSCs using current Electric Power Research Institute guidelines
  • Accounted for sliding and rocking of unanchored equipment in developing seismic fragilities for functional failure
  • Modeled and analyzed older steel-framed and masonry buildings that were not designed or detailed to current criteria

Project Summary



Completion Date
Repair & Rehabilitation
Structures | Advanced Analysis
Battelle Energy Alliance
Specialized Capabilities
Seismic Engineering | Nuclear

Key team members

Philip Hashimoto
Philip Hashimoto
Senior Principal