Belgian nuclear research centre SCK•CEN has signed an agreement with accelerator manufacturer IBA to jointly design and develop a demonstration plant for a new type of sub-critical reactor. The project, to be called MYRRHA, would be the first demonstration of a new class of safer nuclear reactors in which the core is sub-critical, (ie it is kept below critical mass) and so cannot on its own go into uncontrolled chain fission. In operation, fission is maintained by the injection of a stream of high energy neutrons driven by a high powered accelerator. The other major advantage of the system is its ability to burn nuclear waste. Under the agreement SCK•CEN will develop the nuclear core and the spallation neutron source and IBA will design and manufacture the accelerator. Construction of the prototype is due to begin in 2004.