The MYRRHA spallation target must fulfil a number of requirements imposed by the general concept of the MYRRHA ADS:
- The target should produce enough neutrons to feed the sub-critical core at its keff value of 0.95. Approximately 2.1017 neutrons are produced by a 600 MeV, maximum 4 mA proton beam delivered by an accelerator and impinging on a heavy metal spallation target.
- In the process, about 65 % of the total beam power, i.e. ≈ 2.1 MW, is deposited as heat in the target. Consequently the target has to be able to evacuate this heat.
- In addition, the target must fit in the central hole of the sub-critical core assembly and be as compact as possible to generate the highest possible neutron fluxes in the immediate surroundings of the target.
- Finally, the spallation target must reach an appropriate lifetime and it must comply with the fundamental role of MYRRHA as a flexible high intensity experimental irradiation device
A liquid metal, for which lead-bismuth eutectic (LBE) has been chosen, is selected as target material to obtain a high neutron gain and to allow forced convective heat removal.
Two fundamental design options
In order to match all requirements, two fundamental design options are considered:
A proton impinges upon a heavy metal atom and initiates the spallation process during whichneutrons and protons are set free.
More information: R&D programme > Lead-Bismuth technology