MYRRHA, the Multi-purpose Hybrid Research Reactor for High-tech Applications

The Belgian Nuclear Research Centre (SCK-CEN) is proposing to replace its ageing flagship facility, the Material Testing Reactor BR2, by a new flexible irradiation facility, MYRRHA. Considering the international and European needs, MYRRHA is conceived as a flexible fast spectrum irradiation facility able to work in both sub-critical and critical mode. Initially MYRRHA was designed as a multi-purpose accelerator driven system (XT-ADS) and consisted of a proton accelerator delivering its beam to a liquid Lead-Bismuth spallation target that in turn coupled to a sub-critical fast core, also cooled with Lead-Bismuth. The initial concept has been modified to respond to the objective of operating in critical mode. In this respect it is clear that reactor control and scram systems have to be included in the design. The initial XT-ADS design has evolved into a new concept, called FASTEF. MYRRHA is now foreseen to be in full operation by 2023 and it will be operated first as an Accelerator Driven Systems to demonstrate the ADS technology and the efficient demonstration of minor actinide burning in sub-critical mode. Afterwards it is intended to decouple the accelerator from the reactor and run MYRRHA as a critical facility in support of LFR - Lead-cooled Fast Reactors