Modern HTR nuclear power plants which are now under development (projects GT-MHR, PBMR)
are based on the direct cycle concept. This concept leads to a more important efficiency compared to
the steam cycle but requires the use of high performance components such as an helium/helium heat
exchanger called recuperator to guarantee the cycle efficiency. Using this concept, a net plant
efficiency of around 50% can be achieved in the case of an electricity generating plant. As geometric
constraints are particularly important for such a gas reactor to limit the size of the primary vessels,
compact heat exchangers operating at high pressure and high temperature are attractive potential
solutions for the recuperator application. In this frame, Framatome and CEA have reviewed the
various technologies of compact heat exchangers used in industry. The first part of the paper will give
a short description of the heat exchangers technologies and their rcinges of application. In a second
part, a selection of potential compact heat exchangers technologies are proposed for the recuperator
application. This selection will be based upon their capabilities to cope with the operating conditions
parameters (pressure, temperature, flow rate) and with other parameters such as fouling, corrosion,
compactness, weight, maintenance and reliability.