IFJ PAN Contribution to the ITER Radial Neutron Camera

D. Bocian, J. Kotuła (Inst. of Nuclear Physics PAS, Poland), R. Kantor, P. Młynarczyk (Cracow University of Technology, Poland)

The Radial Neutron Camera (RNC) is a diagnostic system developed for ITER by international consortium lead by ENEA, Frascati. The RNC, located in the Equatorial Port Plug 1 (EPP1) is designed as a multichannel detection system to measure the uncollided neutron flux from the plasma. The measured neutrons, generated in the tokamak vacuum vessel, provides information on total intensity of the neutron source, neutron emissivity/temperature profile of plasma and tritium/deuterium ratio. The RNC is the array of cylindrical collimators located in ITER diagnostic structures: the ex-port system and the in-port system. The ex-port system measures the plasma core with two sets of lines of sight, lying on two neighbouring cross-section planes of toroidal vacuum vessel. The in-port system is dedicated for measurements of neutron flux generated in the plasma edge and it consists of two sets of lines of sight, lying on two neighbouring cross-section planes, as well. The operating temperature and radiation are vital parameter of nominal operation of RNC system, especially in-port system. The expected temperature in ITER equatorial ports is of order of 125°C during normal operation whereas during the ITER baking process the maximum water outlet temperature is ~240 °C, causing the maximum temperature of the in-port structure at the same level. In addition the maximum target temperature for the diamond detectors used in RNC is set to be of order of 150 °C. The conditions described above require a cooling system with a function of temperature protection of RNC sensitive components during the ITER baking phase. The developed in-port cassette includes the cooling system active during baking phase, based on the concept of a water jacket for each detector module. The current status of design and development work is presented. In order to verify the thermal properties of diamond detectors a dedicated experimental system was designed and build in IFJ PAN. The technical details of the system and results obtained during measurement campaign are presented as well. Also, the concepts of rotating collimators and rotating detectors were disigned by IFJ PAN team. This paper presents the overview of IFJ PAN contribution to the development of Radial Neutron Camera (RNC) developed for ITER project.