The Myrrha linear accelerator

Ac­cel­er­a­tor Driv­en Sys­tems (ADS) are promis­ing tools for the ef­fi­cient trans­mu­ta­tion of nu­cle­ar waste prod­ucts in ded­i­cat­ed in­dus­tri­al in­stal­la­tions, called trans­muters. The Myrrha pro­ject at Mol, Bel­gium, placed it­self on the path to­wards these ap­pli­ca­tions with a mul­ti­pur­pose and ver­sa­tile sys­tem based on a liq­uid PbBi (LBE) cooled fast re­ac­tor (80 MWth) which may be op­er­at­ed in both crit­i­cal and sub­crit­i­cal modes. In the lat­ter case the core is fed by spal­la­tion neu­trons ob­tained from a 600 MeV pro­ton beam hit­ting the LBE coolant/tar­get. The ac­cel­er­a­tor pro­vid­ing this beam is a high in­ten­si­ty CW su­per­con­duct­ing linac which is laid out for the high­est achiev­able re­li­a­bil­i­ty. The com­bi­na­tion of a par­al­lel re­dun­dant and of a fault tol­er­ant scheme should allow ob­tain­ing an MTBF value in ex­cess of 250 hours that is re­quired for op­ti­mal in­tegri­ty and suc­cess­ful op­er­a­tion of the ADS. Myrrha is ex­pect­ed to be op­er­a­tional in 2023. The forth­com­ing 4-year pe­ri­od is fully ded­i­cat­ed to R&D ac­tiv­i­ties, and in the field of the ac­cel­er­a­tor they are strong­ly fo­cused on the re­li­a­bil­i­ty as­pects and on the prop­er shap­ing of the beam trip spec­trum.