August 2011
Review of Requirements and Capabilities for Analyzing and Responding to Beyond Design Basis Events
The U.S. Department of Energy (DOE) has established a rigorous nuclear safety regulatory infrastructure for the protection of workers, the public, and the environment. Part of this infrastructure includes processes for evaluating events to foster continuous improvement. In this spirit, DOE (including the National Nuclear Security Administration) took the following actions to review the safety of its nuclear facilities and identify opportunities for improvement in light of the March 2011 accident at the Fukushima Daiichi nuclear power plant:
- Issued Safety Bulletin 2011-01, • Events Beyond Design Safety Basis Analysis, which requested DOE Program and Field Offices to review their nuclear facilities and report on (1) the analyses that have been performed for beyond design basis events and controls in place that could mitigate them, (2) the ability to safely manage their nuclear facilities during a total loss of power, (3) the operability of important safety systems, and (4) the readiness of emergency management plans and procedures.
- Conducted an analysis of DOE requirements and guidance for safety analysis, facility design, and • emergency response as they relate to beyond design basis events.
- Performed a review of commercial nuclear power industry requirements and guidance related to • beyond design basis events, including recent efforts by the U.S. Nuclear Regulatory Commission and the European Union to evaluate and enhance these requirements and guidance.
- Conducted a Nuclear Safety Workshop that was attended by senior nuclear safety managers and • technical experts from DOE, other Federal agencies (such as the Nuclear Regulatory Commission, the Defense Nuclear Facilities Safety Board, and the Federal Emergency Management Agency), and the commercial nuclear power industry.
These actions focused on learning how DOE can better prepare to manage potential beyond design basis events (i.e., events more severe than the events that formed the basis of the design for DOE’s nuclear facilities, such as extremely unlikely earthquakes). While DOE nuclear facilities significantly differ from commercial nuclear power reactors (particularly in regards to energy and decay heat removal needs during accidents), there are lessons from review of the accident at the Fukushima Daiichi nuclear plant. This report describes the opportunities for improvement identified by DOE’s review and provides recommendations for short-term and long-term actions for improving DOE’s nuclear safety.