Speaker
Nicola Fonnesu
(Department of Fusion and Nuclear Safety Technology)
Description
The assessment of the Shutdown Dose Rate (SDR) due to neutron activation is a major safety issue for fusion devices and in the last decade several benchmark experiments have been conducted at JET during Deuterium-Deuterium shutdown for the validation of the numerical tools used in ITER nuclear analyses. The future Deuterium-Tritium campaign at JET (DTE-2) will provide a unique opportunity to validate the codes under ITER-relevant conditions and a novel SDR experiment is in preparation in the frame of the NEXP-JET3 subproject within EUROfusion Consortium. The experimental setup for the future SDR experiment has been accurately designed to reduce risks and uncertainties and preliminary tests and calibration of the active system were performed. Spherical air-vented ionization chambers (ICs) will be used for on-line ex-vessel decay gamma dose measurements during JET shutdown following DT operations. Activation foils have been selected for measuring the neutron fluence near the ICs during operations. The systems will be located at the side port of Octant 1 (close to the radial neutron camera) and on top of the ITER-like Antenna (ILA) in Octant 2 on proper low activation shelves. Neutron irradiation tests were carried-out at the Frascati Neutron Generator (FNG) with the aim of assessing the correct functioning of the detector after 14 MeV neutron irradiation and for checking the self-activation of the detector induced by neutrons.
The present work is dedicated to the preparation of the Shutdown Dose Rate experiment for the next Deuterium-Tritium campaign. The selected experimental equipment together with results of calibration and irradiation tests of ICs are described. Tests at the FNG confirmed the capability of the dosimetry systems to perform on-line decay gamma dose rate measurements, to follow gamma dose decay at the end of neutron irradiation as well as insignificant activation of the detectors.
Co-authors
Axel Klix
(Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Karlsruhe, Germany)
Nicola Fonnesu
(Department of Fusion and Nuclear Safety Technology, ENEA, 00044 Frascati (Rome), Italy;Department of Industrial Engineering, University of Rome 'Tor Vergata', 1, Via del Politecnico, 00133 Rome, Italy)
Paola Batistoni
(Department of Fusion and Nuclear Safety Technology, ENEA, 00044 Frascati (Rome), Italy)
Riccardo Pilotti
(Department of Fusion and Nuclear Safety Technology, ENEA, 00044 Frascati (Rome), Italy;Department of Industrial Engineering, University of Rome 'Tor Vergata', 1, Via del Politecnico, 00133 Rome, Italy)
Rosaria Villari
(Department of Fusion and Nuclear Safety Technology, ENEA, 00044 Frascati (Rome), Italy)
Stefano Loreti
(Department of Fusion and Nuclear Safety Technology, ENEA, 00044 Frascati (Rome), Italy)
contributors JET
(EUROfusion Consortium, JET, Culham Science Centre, Abingdon, OX14 3DB, United Kingdom)
