Nuclear performance of the D–D phase of ITER

Improved in situ calibration technique for ITER ex-vessel neutron yield monitor

“…As the tritium concentration in the advanced DD-phase considerably varies according to the tritium removal efficiency, a neutron ratio DT/DD: 0.2-1 in this phase was quoted from reference [1]. In this phase, the plasma neutron source becomes a two-component neutron source consisting of DD and DT neutrons.…”

“…5) and the actual plasma DT/DD neutron ratio. The contribution ratio of the summed calibration curve (DT/DD = 0.5) has been assumed uniformly, while the actual plasma neutron ratio varies from 0.2 to 1 [1] as the operational conditions changes. A real time feedback of measurement results by a neutron spectrometer (DT/DD neutron ratio measurement) in each phase would enable further uncertainty improvement.…”

“…In the high density D plasma called "advanced DD-phase", the plasma becomes a two-component (DD and DT) neutron source because of the high energy triton production from one branch of the DD reactions. It has been reported that the neutron ratio (DT/DD) of the twocomponent neutron source can be increased up to 1 [1]. Taking into consideration the two kinds of neutrons, the neutron diagnostic system should be calibrated to both DD and DT neutrons, otherwise the measurement system would suffer from significant measurement uncertainties.…”

“…the true value due to the energy dependence of the detector response % Neutron source contribution to the calibration curve Early stage of the DD-phase Advanced DD-phase DT-phase DT only -Less than −35 Better than −0.69 DD onlyBetter than + 2.3 Less than +38 -Both DT and DD (contribution ratio DT/DD = 0.5) -±22 -a Reference[1].…”

Neutronics analysis for the test blanket modules proposed for EAST and ITER

“…The main parameters of EAST and ITER are listed in table 1. The neutron yield, which is about 10 15 -10 17 n s −1 in the EAST D-D phase, is comparable to it (about 10 17 -10 18 n s −1 ) in the ITER D-D phase [7]. Therefore, EAST is expected to serve as a valuable pre-testing platform for TBMs, which are not only for electro-magnetics (EM) and thermomechanics but also for neutronics.…”