or coping strategies. The procedures would also address the restoration of onsite and offsite AC power sources.
A key difference between EOPs and SAMG is that the former are subject to regulatory oversight (see USNRC, 1982) whereas SAMG are a voluntary industry program. Another important difference is that SAMG anticipate that the engineering staff in the technical support center will be available to guide reactor operators in applying the guidance and evaluating trade-offs that inevitably occur in severe accident management, whereas EOPs enable control room staff to engage in immediate symptom-based responses. Transition points between EOPs and SAMG are defined, but some element of judgment is required to determine whether the transition criteria have been met. Consequently, operator training and education play an important role in making timely decisions.
SAMG make use of both standard and nonstandard plant systems. They include approaches to evaluate plant conditions, select the appropriate guidance, and evaluate the effectiveness of the selected guidance during a severe event. It also includes training plans for staff expected to be involved in any of the following three activities: (1) evaluation of plant damage, (2) making decisions on which strategies to implement, or (3) implementing the selected strategies.
NEI 91-04 (NEI, 1994) recommends that plants self-evaluate their strategies through use of periodic minidrills that ensure that personnel who would be involved in the emergency response are familiar with the implementation of SAMG. However, since SAMG are considered an industry initiative, the USNRC has no specific regulatory control. Instead, the USNRC has accepted the industry’s commitment to assess its capabilities and implement appropriate improvements within the constraints of existing personnel and hardware (Taylor, 1996). In other words, the range of severe accident scenarios that could be managed with the training and steps outlined in the SAMG is limited to those situations that do not require additional resources in staffing or equipment.
Within the last decade, new requirements going beyond this limited approach have been created to respond to potential terrorist attacks. The events at the Fukushima Daiichi plant have further emphasized the need for a more comprehensive approach to severe accident management. Indeed, industry is in the process of developing and implementing new SAMG and associated physical resources.
Following the terrorist attacks of Sept 11, 2001, there was significant concern in the United States about attacks on nuclear power plants using hijacked airplanes or other means (e.g., NRC, 2004b). The USNRC and