Dirk Vandeplassche

Euratom MAX Project: The MYRRHA Accelerator eXperiment R&D Program

The goal of the MYRRHA project is to demonstrate the technical feasibility of transmutation in a 100 MWth accelerator-driven system (ADS) by building a new flexible irradiation complex in Mol (Belgium). The MYRRHA facility requires a 600 MeV accelerator, delivering a maximum proton flux of 4 mA in continuous operation, with an additional requirement for exceptional reliability. This paper will briefly describe the present status of this ADS accelerator design, and will then focus on fault tolerance aspects and their impact on the beam operation, and the ongoing R&D activities.

Cryogenic system for the MYRRHA superconducting linear accelerator

SCK⋅CEN, the Belgian Nuclear Research Centre, is designing MYRRHA, a flexible fast spectrum research reactor (80 MWth), conceived as an accelerator driven system (ADS), able to operate in sub-critical and critical modes. It contains a continuous-wave (CW) superconducting (SC) proton accelerator of 600 MeV, a spallation target and a multiplying core with MOX fuel, cooled by liquid lead-bismuth (Pb-Bi). From 17 MeV onward, the SC accelerator will consist of 48 β=0.36 spoke-loaded cavities (352 MHz), 34 β=0.47 elliptical cavities (704 MHz) and 60 β=0.65 elliptical cavities (704 MHz). We present an analysis of the thermal loads and of the optimal operating temperature of the cryogenic system. In particular, the low operating frequency of spoke cavities makes their operation in CW mode possible both at 4.2 K or at 2 K. Our analysis outlines the main factors that determine at what temperature the spoke cavities should be operated. We then present different cryogenic fluid distribution schemes, important charact...

MYRRHA, A MULTIPURPOSE ACCELERATOR DRIVEN SYSTEM FOR R&D - PRESENT STATUS

One of the SCK.CEN core competencies is and has at all times been the conception, design and realisation of large nuclear research facilities such as BR1, BR2, BR3, VENUS reactors, LHMA hot-cells, or HADES underground research laboratory (URL) for waste disposal. SCK.CEN has then operated these facilities successfully thanks to the high degree of qualification and competency of its personnel and by inserting these facilities in international research networks, contributing hence to the development of crucial aspects of nuclear energy. One of the main SCK.CEN research facility, namely BR2, is nowadays arriving at an age of 40 years just like the major materials testing reactors (MTR) in the world and in Europe (HFR (EU-Petten), OSIRIS (F-Saclay), R2 (Sw-Studsvik)). MYRRHA has been conceived as a potential facility for replacing BR2 and to be a fast spectrum facility complementary to the thermal spectrum RJH (Reacteur Jules Horowitz) facility in France. This situation would give Europe a full research capability in terms of nuclear R&D. Furthermore, the disposal of radioactive wastes resulting from industrial nuclear energy production has still to find a fully satisfactory solution, especially in terms of environmental and social acceptability. As a consequence, most countries with significant nuclear power generating capacity are currently investigating various options for the disposal of their nuclear waste. Scientists are looking for ways to drastically reduce (by a factor of 100 or more) the radio-toxicity of the High Level Waste (HLW) to be stored in a deep geological repository, and to reduce the time needed to reach the radioactivity level of the fuel originally used to produce energy. This can be achieved via the development of the Partitioning and Transmutation and burning MAs and to a less extent LLFPs in Accelerator Driven Systems. The MYRRHA project contribution will be in helping to demonstrate the ADS concept at reasonable power level and the demonstration of the technological feasibility of MA and LLFP transmutation in real conditions.