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In order to provide an appropriate level of energy to the whole world, nuclear energy is still going to play an important role. Nuclear energy can help reducing the CO2 emissions, which today are excessive. The problematics of nuclear waste can be solved using long-term geological storage in deep suitable formations. Partitioning and transmutation can help reducing the radiotoxicity of spent fuel to more acceptable durations of time. The MYRRHA project investigates since more than 20 years the possibility to demonstrate transmutation at a reasonable power level. In this paper we present the current state of the MYRRHA reactor design and the associated research and development activities.

The BR2 reactor is a pressurized "tank-in-pool" type reactor, cooled with water and moderated by its beryllium structure and water. Reactor BR2 Belgian Reactor 2 (BR2, Figure 2) was constructed as a materials testing reactor, being (from its start of operation in 1962) one of the most powerful research reactors in the world. Was founded in the 1950s to study the applications of nuclear energy, but since then it has expanded its knowledge to a wide range of research fields, with a strongly future-oriented and international focus. This air-cooled graphite-moderated reactor was commissioned in 1956 and used primarily for research into reactor and neutron physics and the production of radioisotopes. [Extracted from the article]

One of the major challenges that our society faces is the increasing demand for energy in general and electricity in particular. During the last century our energy supply was based on fossil fuels. Nowadays, we are confronted with decreasing hydrocarbon reserves and excessive CO2 emissions. At the same time renewable energy sources cannot satisfy the complete demand. For this reason the European Union, Japan, the United States, Korea, Russia, China, India, and other countries recognize that nuclear energy needs to be part of the “energy basket” of the future. [ABSTRACT FROM AUTHOR]

In some nuclear reactors the core is intended to be cooled by means of liquid metal, for example, lead-bismuth eutectic alloy. For safety and licensing reasons, an imaging method of the interior of reactor has thus to be developed. The paper is devoted to development of ultrasonic imaging and measurement technique suitable for performance in the liquid Pb/Bi alloy. [ABSTRACT FROM AUTHOR]

Closing the nuclear fuel cycle and transmuting Minor Actinides (MAs) can be considered as an application of the duty of care principle which says that, "before the final disposal of any waste, any possible chemical and/or physical treatment has to be applied in order to reduce the waste's toxicity, provided the treatment does not convey unacceptable risks or unacceptable costs". Forty years of complex research and development has shown that Accelerator Driven Systems could provide a solution to the challenge posed by spent nuclear fuels, by enabling the ability to considerably decrease their radiotoxicity lifetime burden and volume. In particular, a multilateral strategy of treatment of the MAs could be a commendable solution for both the countries phasing out the exploitation of nuclear energy and for those pursuing and developing this exploitation. The pre-industrial assessment of the technical and financial feasibility for industrialization is the next step. This applies to the four R&D and Demonstration building blocks: advanced separation, MAs' loaded fuel fabrication, dedicated transmuters demonstration (MYRRHA) and provision for MAs' fuel loaded processing. A global vision of the process leading to a sustainable option is proposed. [ABSTRACT FROM AUTHOR]

In some nuclear reactors or accelerator-driven systems (ADS) the core is intended to be cooled by means of a heavy liquid metal, for example, lead-bismuth (Pb/Bi) eutectic alloy. For safety and licensing reasons, an imaging method of the interior of ADS, based on application of ultrasonic waves, has thus to be developed. This paper is devoted to description of developed various ultrasonic transducers suitable for long term imaging and measurements in the liquid Pb/Bi alloy. The results of comparative experimental investigations of the developed transducers of different designs in a liquid Pb/Bi alloy up to 450 degrees C are presented. Prototypes with different high temperature piezoelectric materials were investigated: PZT, bismuth titanate (Bi4Ti3O12), lithium niobate (LiNbO3), gallium orthophosphate (GaPO4) and aluminum nitride (A1N). For acoustic coupling with the metal alloy, it was proposed to coat the active surface of the transducers by diamond like carbon (DLC). The radiation robustness was assessed by exposing the transducers to high gamma dose rates in one of the irradiation facilities at SCK x CEN. The experimental results proved that the developed transducers are suitable for long-term operation in harsh conditions.