Fusion neutron diagnostics on ITER tokamak

Abstract

ITER is an experimental nuclear reactor, aiming to demonstrate the feasibility of nuclear fusion realization in order to use it as a new source of energy. ITER is a plasma device (tokamak type) which will be equipped with a set of plasma diagnostic tools to satisfy three key requirements: machine protection, plasma control and physics studies by measuring about 100 different parameters. ITER diagnostic equipment is integrated in several ports at upper, equatorial and divertor levels as well internally in many vacuum vessel locations. The Diagnostic Systems will be procured from ITER Members (Japan, Russia, India, United States, Japan, Korea and European Union) mainly with the supporting structures in the ports. The various diagnostics will be challenged by high nuclear radiation and electromagnetic fields as well by severe environmental conditions (ultra high vacuum, high thermal loads). Several neutron systems with different sensitivities are foreseen to measure ITER expected neutron emission from 10 14 up to almost 10 21 n/s. The measurement of total neutron emissivity is performed by means of Neutron Flux Monitors (NFM) installed in diagnostic ports and by Divertor Neutron Flux Monitors (DNFM) plus MicroFission Chambers (MFC) located inside the vacuum vessel. The neutron emission profile is measured with radial and vertical neutron cameras. Spectroscopy is accomplished with spectrometers looking particularly at 2.5 and 14 MeV neutron energy. Neutron Activation System (NAS), with irradiation ends inside the vacuum vessel, provide neutron yield data. A calibration strategy of the neutron diagnostics has been developed foreseeing in situ and cross calibration campaigns. An overview of ITER neutron diagnostic systems and of the associated challenging engineering and integration issues will be reported.

Neutron diagnostics for the physics of a high-field, compact, Q ≥ 1 tokamak

“…NFMs have been implemented on many tokamaks including Alcator C-Mod [18], DIII-D [19], TFTR [20,21,22,23,24], and JET [25,26,27,28,29], among others, and are planned to be used on ITER [15,30,31]. Examples of these detectors include BF 3 and 3 He proportional counters [16], 235 U and 238 U fission chambers [16], scintillators [19], and diamond detectors [30].…”

“…Neutron spectrometers in various configurations have been used on TFTR [33,34] and JET [35,36], among other devices [37], and are planned for ITER [38]; although, the current design for ITER's high resolution spectrometer is left unspecified [31]. for 95% con-dence of Q 6 1 There are multiple approaches to diagnose neutron energy spectra, many of which show promise for near-burning plasma experiments [39]; examples are magnetic proton recoil (MPR) [40], solid state diamond detection [41], time-of-flight measurements [35], and scintillators coupled to pulse-shape discrimination systems [42].…”

Development of FPGA-Based Real-Time Neutron Spectrometer Using Stilbene Scintillator

“…Neutron diagnostic is an important tool for determining fusion power, power density and the plasma ion temperature in experiments with hot deuterium and tritium plasmas [1]. Furthermore the neutron spectrometer is an ultimate instrument for determining the relative power released in each of the reactions (DD reaction and DT reaction) in the forthcoming experiments with DT plasma.…”

A new concept of fusion neutron monitoring for PF-1000 device

“…All the time when the neutron yield is in use, it has a meaning of total neutron emission in all directions during the time period, which is characteristic for particular device usually the cycle, pulse, or shot. For the International Thermonuclear Experimental Reactor (ITER) tokamak, Y n diagnosis and analysis is expected to provide crucial insight on plasmas, as well as information for protection and control [3]. Neutron diagnostics using the Joint European Torus (JET) neutron camera and the neutron time--of-fl ight spectrometer are used to estimate the fuel density profi le in the JET deuterium plasma [4].…”