Thermal feed-back effects in a pool-type LMFBR: theoretical and experimental results on PHENIX reactor

A physical description of the different thermal feedback effects occurring in a pool-type LMFBR of the PHENIX or SUPER PHENIX type is made (sodium density, clad and hexcan expansion, axial fuel expansion, radial grid plate and pad expansion, differential expansion between the core and the control rods, Doppler effects). Theoretical values are given for each of these effects occurring in the PHENIX reactor, as well as for different sets of effects which can be measured on the reactor itself. The experiments on the reactor which lead to these measurements are described and the corresponding values are given and compared with the theoretical ones. Some interpretations, and quantitative conclusions for SUPER PHENIX are made