MONITORING OF 14 MeV NEUTRONS

Long-lived fission products and minor actinides produced in nuclear power plants are the most radiotoxic nuclear wastes. They can be transmuted into stable nuclei or into nuclei with shorter lifetime thanks to the so-called Accelerator Driven Systems (ADS), consisting of the coupling of an intense high energy proton beam, a spallation target and a sub-critical reactor core. For safety reasons, an on-line and robust measurement of the reactivity during loading and power operation is mandatory. The investigation of the relationship between the current of the accelerator and the power level (or neutron flux) of the reactor appears to be powerful, any change in reactivity being accessible through the measurement of the current and the flux. Such a relationship will be studied in an experiment to be performed at the YALINA facility (JIPNR Sosny - Belarus) in the framework of the EUROTRANS IP (6 th FP). At this installation, 14 MeV neutrons are produced in T(d,n) 4 He reactions by a deuteron beam impinging on a TiT target. Due to the tritium consumption over time, the intensity of the deuteron beam cannot be used for the monitoring of the neutron beam. The source neutron yield itself has to be accessed. This contribution describes the performance of a three-element silicon telescope dedicated to the detection of recoil protons produced in reactions induced by 14 MeV neutrons.