Japan Atomic Energy Research Institute

About: Japan Atomic Energy Research Institute is a based out in . It is known for research contribution in the topics: Neutron & Irradiation. The organization has 7707 authors who have published 14471 publications receiving 207688 citations.

On the heating mix of ITER

Abstract: This paper considers the heating mix of ITER for the two main scenarios. Presently, 73 MW of absorbed power are foreseen in the mix 20/33/20 for ECH, NBI and ICH. Given a sufficient edge stability, Q = 10-the goal of scenario 2-can be reached with 40MW power irrespective of the heating method but depends sensitively inter alia on the H-mode pedestal temperature, the density profile shape and on the characteristics of impurity transport. ICH preferentially heats the ions and would contribute specifically with Delta Q 0.5, and strong off-axis current drive (CD). The findings presented here are based on revised CD efficiencies gamma for ECCD and a detailed benchmark of several CD codes. With ECCD alone, the goals of scenario 4 can hardly be reached. Efficient off-axis CD is only possible with NBI. With beams, inductive discharges with f(ni) > 0.8 can be maintained for 3000 s. The conclusion of this study is that the present heating mix of ITER is appropriate. It provides the necessary actuators to induce in a flexible way the best possible scenarios. The development risks of NBI at 1 MeV can be reduced by operation at 0.85 MeV.

Ripple-trapped loss of neutral-beam-injected fast ions in JT-60U

Abstract: Toroidal field ripple loss of neutral-beam-injected fast ions is measured from the heat load on the first wall in JT-60U. The heat load is localized in both toroidal and poloidal directions and increases with both ripple size and safety factor. The overall measured ripple loss is in good agreement with an orbit-following Monte Carlo calculation. Nevertheless, there is a small difference between the experimental and the calculated location of the maximum heat load, which suggests that the radial electric field shifts the impinging points of ripple-trapped ions on the first wall.

Effect of crosslinkers on the preparation and properties of ETFE-based radiation-grafted polymer electrolyte membranes

Abstract: This study concerns a comparative study of three crosslinkers, divinylbenzene (DVB), 1,2-bis(p,p-vinylphenyl)ethane (BVPE), and triallyl cyanurate (TAC) crosslinked poly(ethylene-co-tetrafluoroethylene) (ETFE)-based radiation-grafted membranes, which were prepared by radiation grafting of p-methylstyrene onto ETFE films and subsequent sulfonation. The effect of the different types and contents of the crosslinkers on the grafting and sulfonation, and the properties such as water uptake, proton conductivity, and thermal/chemical stability of the resulting polymer electrolyte membranes were investigated in detail. Introducing crosslink structure into the radiation-grafted membranes leads to a decrease in proton conductivity due to the decrease in water uptake. The thermal stability of the crosslinked radiation-grafted membranes is also somewhat lower than that of the noncrosslinked one. However, the crosslinked radiation-grafted membranes show significantly higher chemical stability characterized in the 3% H2O2 at 50°C. Among the three crosslinkers, the DVB shows a most pronounced efficiency on the crosslinking of the radiation-grafted membranes, while the TAC has no significant influence; the BVPE is a mild and effective crosslinker, showing the moderate influence between the DVB and TAC crosslinkers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4565–4574, 2006

Nuclide Composition Benchmark Data Set for Verifying Burnup Codes on Spent Light Water Reactor Fuels

Abstract: To establish a nuclide composition benchmark data set for the verification of burnup codes, destructive analyses of light water reactor spent-fuel samples, which were cut out from several heights of spent-fuel rods, were carried out at the analytical laboratory at the Japan Atomic Energy Research Institute. The 16 samples from three kinds of pressurized water reactor (PWR) fuel rods and the 18 samples from two boiling water reactor (BWR) fuel rods were examined. Their initial 235U enrichments and burnups were from 2.6 to 4.1% and from 4 to 50 GWd/t, respectively. One PWR fuel rod and one BWR fuel rod contained gadolinia as a burnable poison. The measurements for more than 40 nuclides of uranium, transuranium, and fission product elements were performed by destructive analysis using mass spectrometry, and alpha-ray and gamma-ray spectrometry. Burnup for each sample was determined by the 148Nd method. The analytical methods and the results as well as the related irradiation condition data are compil...