Overview of Allegro Project
25th Symposium of AER on VVER Reactor Physics and Reactor Safety (2015, Balatongyörök, Hungary)
Nuclear fuel Cycle Perspectives and Sustainability
The goal of the ALLEGRO Project is to design, build and operate the first Gas cooled Fast
Reactor (GFR) Demonstrator. The GFR belongs to the 4th generation of nuclear reactors.
Prototype of the gas cooled reactor ALLEGRO is a subject of common interest of association
of countries France, Slovakia, the Czech Republic and Hungary with the goal to deploy
prototype of the reactor in Central Europe and present its functionality. Nuclear research
institutions of the four Visegrad countries (V4) agreed on establishment of “V4G4 Centre of
Excellence” on July 18, 2013, for performing common R&D in the area of Generation IV
reactors. The agreement allows participants to join their resources for development of
Generation IV reactors and thus contribute to meeting the goal of sustainability of nuclear
energy while maintaining the highest safety standards.
OBJECTIVE AND MISSION
An ALLEGRO demonstrator is an essential step to establish confidence in the innovative Gas
Cooled Fast Reactor (GFR) technology. The proposed demonstrator, would be the first ever
gas cooled fast reactor to be constructed. The objectives of ALLEGRO are to demonstrate the
viability and to qualify specific GFR technologies such as fuel, the fuel elements, heliumrelated technologies and specific safety systems. In particular, the decay heat removal
function, together with demonstration that these features can be integrated successfully into a
representative system 1 is of great interest.
The attractive GFR concept aims to combine the benefits of fast spectrum and high output
temperature (up to 850 ?C), using helium as a coolant.
The high coolant temperature allows targeting high energy conversion efficiency (43-48 %)
and opens the possibilities for new application of nuclear energy, such as heat intensive
processes (metallurgy, hydrogen or synthetic hydrocarbon fuel production?). The GFR
concept aims to provide these new potentialities by affording a sustainable energy supply in
the long term.
In comparison with sodium, gas coolants have the following advantages for fast reactor
? Chemical compatibility with water, obviating the need of an intermediate coolant loop,
and generally good chemical compatibility with structural materials.
? Negligible activation of coolant.
? Optical transparent, simplifying fuel shuffling operations and inspection.