DT-Plasma Driven Sub-Critical Systems

Introduction

Development and introduction of innovative closed fuel cycle options and technological solutions for the spent nuclear fuel problem are essential for nuclear power to be a long-term sustainable option for the world’s energy mix.

Scenarios for the transmutation and incineration of various long-lived isotopes (actinides and fission products) are being put forward and studied internationally, both as national, bi- or multi-lateral R&D efforts. One of the novel scenarios being proposed is to use sub-critical assemblies driven by an external neutron source. Potential advantages of this approach as compared to critical fast reactors are:

Currently, the most prominent example of external neutron sources is an accelerator driven spallation neutron source. More recently, the possibility of driving a sub-critical fission blanket with 14 MeV neutrons from a DT-plasma source has generated increasing interest. DT-fusion-plasma/fission systems promise some advantages when compared to other sub-critical concepts under consideration. The 14 MeV neutrons offer additional flexibility with regard to, the neutron economy [additional neutrons from (n,2n), (n,3n), and other threshold nuclear reactions] allowing even lower keff regimes. The volumetric nature and associated lower power density of the neutron source (i.e., of the plasma) as compared to a spallation neutron source opens new design possibilities for the sub-critical fission blanket. Further, the technical demands on a DT-fusion-plasma neutron source are lower by more than an order of magnitude compared to those of a pure fusion system. This reduction in technical demands is thought to lead to lower costs compared to pure fusion systems.

IAEA’s Department for Nuclear Energy (NE) is enhancing its activities in the field of DT-fusion-plasma/fission systems for energy production and transmutation, and to closely coordinate and cooperate with the Division of Physical and Chemical Sciences within the Department of Nuclear Sciences and Applications (NA). These activities are implemented in the Nuclear Power Technology Development Section (NPTDS) within the framework of the Technical Working Group on Fast Reactors (TWG-FR).

Meeting Report

Consultancy on the "Potential of Fusion/Fission Sub-Critical Neutron Systems for Energy Production and Transmutation", Vienna, 15-17 June, 2005 Meeting Report