[en] This report analyses the use and qualification of miniature fission chambers for two types of neutron measurements: 1) relative measurements in nuclear power reactors, or nuclear irradiation reactors. We consider the problem of burnable fissile material in detectors, under important neutron exposures and conclude on recommending the use of regenerating neutron detectors. 2) Measurements of integral physical parameters in experimental reactors. This method has been applied to measurements of fission rates in detectors with strong alpha-rays emitter deposits in order to establish standard tables of physical parameters. It has been used in particular for detectors including very radioactive actinium series. After a discussion of the instrumentation choice and data processing, specific to each measurements, we provide results on: 1) the technological and neutron behaviour of regenerating miniature fission chambers, in the swimming pool reactor 'TRITON', under a neutron exposure of 7.10²⁰ n cm^-2 and a gamma-rays exposure of 1,5.10¹¹ rads about. The fissile material is ²³⁵U and the fertile material ²³⁴U. 2) The integral measurements of effective cross sections for ²⁴¹Am and ²³⁸Pu in the experimental reactor 'MINERVE' use for study of problems of fast neutron reactors