CSNI Technical Opinion Paper No. 17: Fire Probabilistic Safety Assessments for Nuclear Power Plants: 2019 Update provides an authoritative review of the current status and use of the fire PSA in nuclear power plants. The report demonstrates that while fires at a particular plant site are highly dependent on plant and site specific factors, they are nonetheless an important contributor to overall risk. Insights from fire PSAs are generally found to be aligned with operating experience and to be representative of the expected plant response, making them valuable in addressing risk. This report should be useful for regulators overseeing the use of fire PSAs in nuclear installations, practitioners in understanding the considerations for performing or reviewing fire PSAs, and researchers in identifying areas requiring further study.