The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid.

The development of hydrothermal energy for direct heat applications is being aided by twenty-two demonstration projects that are funded on a cost-sharing basis by the US Department of Energy, Division of Geothermal Energy. These projects are designed to demonstrate the technical and economic feasibility of the direct use of geothermal heat in the United States. Twelve of these projects are administered by the DOE-Idaho Operations Office with technical support from EG and G Idaho, Inc. Engineering and economic data for these projects are summarized in this paper. The data and experience being generated by these projects will be an important basis for future geothermal direct use projects.

The US Department of Energy (DOE) is involved in numerous geothermal research, development, demonstration, and loan guaranty projects in the State of California. These projects often require the preparation of both an Environmental Impact Report (EIR), as required by California Environmental Quality Act (CEQA), and an Environmental Assessment (EA) or Impact Statement (EIS) as required under NEPA. DOE adoption or utilization of information contained in EIR's to meet that agency's NEPA requirements and thereby reduce duplication of effort is dependent on four critical issues: (1) the scope of the proposed action analyzed, (2) the completeness of treatment of environmental issues, (3) the level of DOE involvement in EIR preparation, and (4) the timing of DOE involvement in EIR preparation. At this time, several constraints prevent the integration of the DOE Loan Guaranty and CEQA environmental review and documentation processes. First, the time required to complete an EIR (up to 2 years in some cases) is not compatible with DOE's goal of processing loan guaranty applications within a 4 month period. Second, the CEQA process is usually initiated and completed prior to DOE's involvement in the project. Therefore, DOE often has no role in document preparation and must verify the content …