The 2005 Long Term Plan was renamed the Framework for Nuclear Energy Policy and established a new fast breeder reactor commercialization target of 2050.7 In 2006, the Sub-committee on Nuclear Energy Policy of the Government’s Advisory Council on Energy published Japan’s Nuclear Power National Plan, which laid out detailed policy measures based on the JAEC’s framework.8 The Nuclear Power National Plan reiterates the 2050 commercialization target for the fast breeder reactor and announced a goal of developing a post-Monju demonstration fast breeder reactor by 2025. The associated Phase II "Feasibility Study on Commercialization of Fast Reactor Cycle Systems" compared various types of fast reactor designs and associated fuel cycle technologies, and tentatively identified a sodium-cooled fast reactor with advanced wet reprocessing technology as the preferred option.9

The study compared four fast-neutron reactor designs: sodium-cooled (1.5 gigawatt electric (GWe)) with metallic fuel, helium-cooled (1.5 GWe) with nitride fuel, lead-bismuth-cooled (0.75 GWe) with nitride fuel, and water-cooled (1.356 GWe) with mixed oxide fuel (MOX). Unit construction cost estimates for a sodium- cooled fast breeder reactor would be the lowest ¥180,000/kilowatt compared with approximately ¥200,000/kilowatt electric for the other designs. Four basic options for advanced reprocessing and fuel technologies were evaluated:

1. Advanced wet reprocessing plus simplified pelletized MOX fuel;

2. Metal electro-refining reprocessing plus injection cast metallic fuel;

3. Advanced wet reprocessing plus vibration packing (Sphere-pack) MOX fuel; and,

4. Oxide electro-refining reprocessing plus vibration packing (Vipac) MOX fuel.

The most economical option would be the advanced wet reprocessing plus simplified pelletized MOX fuel in a large (200 ton/year) plant (~¥0.5-0.66/kWh) with the alternatives costing up to ¥1.6/kWh. None of these cost estimates are engineering estimates. All represent development targets required for fast breeder reactors to be competitive with light-water reactors.

The Nuclear Power National Plan also set out important principles for the future development of fast breeder reactor and fuel cycle systems. First, it established a cost-sharing principle to distribute demonstration fast breeder reactor project costs between the utility companies and the Government. It specified that the private sector would invest an amount equivalent to the cost of a commercial light-water reactor, significantly reducing the financial risk for utilities.10

Another important principle of the Nuclear Power National Plan was that the second commercial reprocessing plant after the Rokkasho plant should be timed to match the pace of fast breeder reactor development and deployment. It suggested that planning for the second reprocessing plant start around 2010.

In 2007, the Government increased the fast breeder reactor R&D budget for the first time since the late 1990s to ¥44 billion in response to these new programs and principles. It is now approximately 10 percent of the total nuclear budget. This budget increase was prompted partially by international developments, notably the announcement of GNEP, which had an initial emphasis on using fast-neutron reactors to fission plutonium and other transuranic elements in light-water reactor spent fuel.

The socio-political factors behind Japan’s entrenched commitment to fast breeder reactor technology

Despite the marked slippage of fast breeder reactor commercialization targets, why have Japanese commitments to the fast breeder reactor remained, at least publicly, unchanged? There are three possible explanations.