Why does the NRC allow post-fire OMAs in lieu of physical protection?
Significant plant fires are unusual events. Often, adequate safety may be ensured through the use of OMAs that have been analyzed and demonstrated to be effective in ensuring safe-shutdown capability. In such cases, the NRC’s paramount goal of safety is achieved without unnecessary regulatory burden being imposed on the licensees. However, where physical protection is needed to ensure adequate safety, the NRC will require physical protection.
