The Reactor Physics Group at LPSC

Formerly called the Hybrid Reactor Group

The research group on Reactor Physics of LPSC belongs to Université Joseph Fourier, INPG (Institut National Polytechnique de Grenoble) and CNRS/IN2P3. It is, thus, essentially an academic group.

Why should such an academic group do research on nuclear reactors?

Our answer is that, considering the degree to which nuclear energy could contribute to the satisfaction of future worldwide energy needs, the field should not be left to industry alone, nor to biased ideologists, nor to the market. Energy planning requires long term projections and a thorough exploration of any promising concepts. Our areas of interest are hybrid reactors, i.e. sub-critical reactors, and critical molten salt reactors. Physicists, like C.D. Bowman and C. Rubbia, have shown that such reactors could help solve the difficulties associated to standard critical reactors.

The evaluation of any nuclear energy production system for the future requires that the following questions be answered:

  What are the competitive energy production systems?

  What are their environmental impact?

  What are the corresponding reserves?

  What is the present and future relative competitivity of each energy production system?

The issues related to energy reserves and environmental problems associated to the production of energy are examined in some detail in World Energy Perspectives. It appears that, if the greenhouse effect is to be taken seriously, fossil fuel burning has to be drastically reduced in the course of this century. While renewable energies like Wind and Solar, should be developed and used wherever possible, it seems that the only large scale, economically competitive, source which can be used as a substitute for fossil fuels is nuclear fission. Nuclear reactors can be used to produce electricity, as they are now; they could also be used to produce hydrogen, as a replacement for fossil fuels in transportation. Thus, if political decision makers were to decide to fight the greenhouse effect efficiently, it seems likely that the contribution of Nuclear Power would have to increase dramaticaly. However, it is conceivable that, as a first step, gas replace coal in emerging countries like China, India and South America, essentially because this could allow an increase in energy production with reduced initial Capital needs while limiting the volume of greenhouse gas emissions.

If a significant extension of the use of nuclear fission in the production of world energy were to occur, it is clear that the systems would have to be breeders. This is true of the systems we are studying in our group:

  Hybrid reactors. These, by associating an accelerator to a sub-critical reactor, have excellent safety characteristics (they could, in particular, be used to test new types of reactors). They are a very attractive option for the incineration of radioactive wastes, thanks to their external neutron source. We have done computer simulations of a solid fuel, liquid lead coolant sub-critical hybrid reactor and of a molten salt sub-critical reactor.

  Critical molten salt reactors. The Thorium-Uranium233 fuel cycle allows breeding with both a thermalized and a fast neutron spectrum. The thermalized spectrum allows a reduced inventory, and this is a major advantage. The results that we have obtained from our simulations of a molten salt reactor with a thermalized spectrum are so encouraging that we are setting up an experiment PEREN in order to verify our findings experimentally.

Last update: 9 April 2003