On the fuel cycle and neutron fluxes of the high flux reactor at ILL Grenoble

The fuel evolution and neutron uxes of the High Flux Reactor at ILL Grenoble were investigated for the full fuel cycle. Two di erent code systems, namely Monteburns and MCNP+CINDER'90, were employed for a realistic 3D-geometry description of the reactor core and experimental channels of interest. Both codes reproduce correctly the history of the fuel burnup. Calculated neutron ux in the reactor core is 2.16 10 n s cm and decreases down to 1.65 10 n s cm and 6.7 10 n s cm in the experimental channels V4 and H9 respectively. Thermal neutron contribution is 85.2% in V4 and 98.3% in H9. We show that neutron uxes in the experimental channels V4 and H9 are not perturbed/changed due to the burnup of the fuel element and/or move of the control rod. This result should simplify most of the irradiation experiments (and data analysis in particular), which employ the experimental channels as above. To be published in the Proceedings of the 5th Int. Specialists' Meeting SATIF-5, OECD/NEA Paris (2000). E-mail: ridikas@cea.fr