13.8.1 BNL

There are three types of ADS under study at BNL (Takahashi, 1997).

The accelerator driven energy producer (ADEP) (Bonnaue et al., 1986) is intended for energy production, incineration of MA and LLFP. This concept uses a small power accelerator similar to that of a segmented cyclotron.

The concept is close to that of the conventional Pu fuelled fast reactor, but is run in slightly sub-critical conditions of keff equal to 0.98-0.99. The cyclotron with a few mA current and 3 GeV energy protons supplies a small spallation source.

The fuel in the ADEP core region is 9Pu + U, and MA in metal and oxide forms.

The reactor has thorium oxide in the blanket region. For transmuting the LLFP such as 99Tc and 129I (by neutron capture), the moderator region is installed between the outer core and blanket. To increase the production of 233U, the moderator region can be fuelled with thorium oxide.

The second approach, known as the Phoenix concept (Van Tuyle et al., 1993) (Figure 13.1) has the purpose of transmuting large amounts of MAs and LLFPs. It is based on modules of accelerator driven sub-critical lattices containing minor actinide fuel. From 1-8 modules serve as a target for an expanded proton beam of power 104 mA of 1.6 GeV protons. Each module of the core has a keff of 0.9 and is based on the fast flux test facility (FFTF) approach, e. g. oxide fuel elements and sodium cooling; with this specification the power generated would be 3600 MW.

The third concept is the accelerator driven particle fuel transmutator (ADPF) (Takahashi, 1990) which also transmutes MAs and LLFPs but at higher rate. This is achieved by means of a high neutron flux via the use of particle fuel.

Particle fuel can be used to generate high thermal power densities, because of its large heat transfer area (Takahashi, 1990). Helium is taken as the coolant because of the data available from conventional HTR technology.