San Diego, California, 17-19 June 2002

Safety and Environmental Aspects of Inertial Fusion Energy: An Overview of Recent Activities and Developments^*

S. Reyes¹ , J. F. Latkowski¹ , L. C. Cadwallader²

¹Lawrence Livermore National Laboratory

²Idaho National Engineering and Environmental Laboratory

reyessuarez1llnl.gov

During the past two years significant progress has been made in several areas related to the safety and environmental (S&E) aspects of inertial fusion energy (IFE). Domestic and international collaboration has been essential for this development. In particular, the S&E efforts at Lawrence Livermore National Laboratory (LLNL) and at the Idaho National Engineering and Environmental Laboratory (INEEL) have produced a substantial advancement in accident analyses for fusion energy power plant designs. An updated methodology has been developed consisting of a state-of-the-art set of codes and libraries for neutron transport and activation, heat transfer calculations and thermal-hydraulics capabilities. Detailed accident analyses have been completed for two IFE power plant conceptual designs: HYLIFE-II and SOMBRERO. To some degree, these designs represent the extremes in IFE power plant designs. Parallel to the consequence analyses of different accident scenarios, ongoing studies of accident initiating events are being used to support safety assessment and create a basic framework of types of events to consider in future risk characterization of new plant designs. Also, a preliminary safety assessment has been performed for a generic target fabrication facility producing various types of targets with leading fabrication techniques. Target designers/fabrication specialists have been provided with ranking information related to the S&E characteristics of candidate target materials from a radiological point of view (e.g., ability to recycle, accident doses, and waste management). Ongoing work in this area will help guide research directions and the selection of target materials.

Besides the radioactive safety issues, special attention is recently being paid to the chemical toxicity hazards of various potential target and coolant materials. For some target material candidates, results show that chemical toxicity may be a critical safety issue. Ongoing work is also addressing chemical hazards of liquid coolants such as the molten salt Flibe (2LiF, BeF₂).

From the environmental perspective, we have recently re-visited waste management options for IFE, introducing the concept of clearance versus the traditional shallow land burial. We have assessed the preferred waste disposal option for each component of the power plant, considering not only the activation level but also the waste stream volume. A brief summary of results in each of these activities is given, and plans for future work are outlined.

^*Work performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract W-7405-Eng-48.