An alternative to nuclear research reactors: The ADONIS-concept

To replace the ageing nuclear reactors used to day for radioisotope production, research and industrial applications, we propose to use a spallation neutron source, with neutron multiplication by fission. A 150 MeV cyclotron will be used to produce a proton beam hitting a molten Pb-Bi primary target producing about 0.8 primary neutron per incident proton. The primary spallation neutrons, moderated, strike a number of secondary targets containing a subcritical amount of ²³⁵U. Typical neutron fluxes at the targets location will be around 6.10¹³n/cm².s. Such a system can be used, for example, to supply more than 50 % of the worlcbdemand in ⁹⁹Mo, the most frequently used radioisotope in nuclear medicine. The non-critical nature of the system makes it more acceptable for the public than a nuclear reactor and simplifies the licensing process. The foreseen investment and operational cost, including radiowaste and decommissioning, of such a system are more favourable than for nuclear reactors. In extra, the licensing procedure is considerably simplified and the time from planning to commissioning might be shorter than four years. This paper discusses the current status of the ADONIS-project and more particularly one of its applications: the optimization of this system as a dedicated ⁹⁹Mo production plant.