Used-fuel recycle and actinide burning to reduce waste and enable the sustainable use of fuel resources.
Other Generation IV goals include enhancing reliability and safety and increasing proliferation resistance and physical security.
From 2002 to 2005, since the publication of the Generation IV Technology Roadmap (DOE, 2002), the Generation IV program was reviewed by the DOE Nuclear Energy Research Advisory Committee (NERAC) on an ongoing basis. In those years, the primary goal of the program was the use of high-temperature (850°C to 1000°C) process heat and innovative approaches to yield energy products, such as hydrogen, that might benefit the transportation and chemical industries. To that end, DOE published an Expression of Interest (DOE, 2004) in the development of industrial and international partnerships for the Next-Generation Nuclear Plant (NGNP), with the VHTR reactor concept as its key focus. This initiative resulted in reviews of the VHTR concept by the Independent Technology Review Group (ITRG, 2004) as well as by NERAC.1 These reviews recommended a faster schedule for the NGNP but a technologically less aggressive approach for the VHTR concept—for example, lower gas outlet temperature, more traditional materials, and proven UO2 particle fuel. These recommendations have largely been adopted as the NGNP program reaches performance-phase R&D. The DOE VHTR effort was reinforced by the passage of the Energy Policy Act of 2005 (EPAct05),2 which authorized $1.25 billion in funding for the NGNP and identified the VHTR as its lead concept. Since FY 2003, over 90 percent of the line item program funds for the Generation IV systems were used for NGNP (see Table 1-1).
In that same time period (2002 to 2005), the secondary goals of the Generation IV program were to examine innovative reactor concepts for managing spent fuel inventories to minimize waste products as well as improve the power conversion efficiency and minimize the cost of advanced reactor systems. These goals were implemented by much smaller efforts in the other four reactor nuclear energy systems. Each reactor concept research program was focused on its main viability issues:
SCWR: advanced materials, chemistry, and heat transfer (T > 500°C),
GFR: alternative fuel types and innovative safety concepts,
LFR: lead corrosion and materials studies, modular reactor design, and
SFR: development of actinide transmutation fuels, and reduction of capital costs through improved design features and power conversion technologies.
At the end of 2005, DOE shifted the fundamental emphasis of the overall AFCI and the Generation IV program, making spent fuel management using a closed fuel cycle the main goal of the NE program by introducing GNEP in early 2006 as part of the budget request for FY 2007. This new priority had a number of effects on the projected funding for the other programs starting in FY 2007:
Reduced funding for the NP 2010 and NGNP programs;
Phasing out of the SCWR, GFR, and LFR R&D programs;
Refocusing the SFR effort on near-term demonstration (Chang et al., 2006; DOE, 2006).
With these changes, NGNP’s VHTR remains the only major reactor concept that is not integrated into the GNEP program. In the sections that follow, the NGNP concept is reviewed first, and the current status of its program plan and its R&D results are assessed. Subsequently, the Nuclear Hydrogen Initiative (NHI) is addressed. Finally, the progress made on the other Generation IV reactor concepts and their current status are examined. The SFR concept, as applied to near-term demonstration, is discussed in greater detail in Chapter 4 because responsibility for its development has been shifted to the GNEP program.
During the development of the Generation IV Technology Roadmap (DOE, 2002), three different R&D phases were defined, going from conceptual design to commercialization:
Viability assessment phase R&D. Viability phase R&D examines the feasibility of key technologies. Its objective is to prove out, on a laboratory scale, the basic concepts, technologies, and processes under relevant conditions and to identify and resolve all potential technical show-stoppers.
Performance assessment phase R&D. Performance phase R&D undertakes the development of performance data and optimization of the system on an engineering scale. The objective is to verify and optimize engineering-scale processes, phenomena, and materials capabilities under prototypical conditions.
Demonstration phase R&D. Demonstration phase activities undertake the licensing, construction, and operation of a prototype or demonstration system in partnership with industry or, perhaps, other countries. The detailed design and licensing of the system are performed during this phase. Its objective is to create a new product that is then selected by industry for wide-scale commercial deployment.