Fusion Studies in Japan

Abstract

Abstract.A new strategic energy plan decided by the Japanese Cabinet in 2014 strongly supports the steady promotion of nuclear fusion development activities, including the ITER project and the Broader Approach activities from the long-term viewpoint. Atomic Energy Commission (AEC) in Japan formulated the Third Phase Basic Program so as to promote an experimental fusion reactor project. In 2005 AEC has reviewed this Program, and discussed on selection and concentration among many projects of fusion reactor development. In addition to the promotion of ITER project, advanced tokamak research by JT-60SA, helical plasma experiment by LHD, FIREX project in laser fusion research and fusion engineering by IFMIF were highly prioritized. Although the basic concept is quite different between tokamak, helical and laser fusion researches, there exist a lot of common features such as plasma physics on 3-D magnetic geometry, high power heat load on plasma facing component and so on. Therefore, a synergetic scenario on fusion reactor development among various plasma confinement concepts would be important. IntroductionJapanese government is promoting fusion research and development based on so-called Phase Basic Program formulated by Atomic Energy Commission (AEC). Currently the third phase basic program started in 1992 has been on progress. This program sets forth key elements of research and development for a DEMO reactor, and is aiming at achieving necessary conditions for the self-ignition and at realizing the long pulse burning plasmas in a tokamak experimental reactor.Based on this principal policy, the ITER has been assigned as a core device in the third phase basic program. While, just before the start of ITER project, this third phase basic program has been reviewed, and report entitled by Future Fusion Research and Development Strategy in the Third Phase Basic Program of Fusion Research and Development was issued in 2005 [1]. In this report action items of recent research and development including ITER project have been described.In 2011 we had a Great East Japan Earthquake, and quite serious nuclear accidents have taken place in Fukushima nuclear power plants. Therefore, in Japan the government has reconsidered energy strategy, and the Cabinet has decided a new strategic energy plan in 2014. In this new strategic energy plan, the Government declares that although nuclear power is expected to be a baseload power supply, Japan will minimize its dependency on nuclear power. While, concerning to nuclear fusion, this report declares that the Japanese government steadily promotes nuclear fusion development activities, including the ITER project, which is being implemented through international cooperation, and the Broader Approach Activities from the long-term viewpoint [2].

Structure of pellet cloud emission and relation with the local ablation rate

“…In this paper, an emission model is used for computing the emission spectra of the ablation clouds all along the pellet lifetime. Synthetic spectra and cloud images are built and compared with measurements of a well documented pellet 4 injected in the Large Helical Device (LHD): stellarator at the National Institute for Fusion Science, Japan [10] (it is noticeable that the characteristics of ablation clouds, which are only function of the local plasma properties, do not depend on the magnetic configuration). The first part of this paper-sections 2 and 3describes the diagnostics used in this study and the procedure for cross calibrating the data.…”

Highly porous tungsten for plasma-facing applications in nuclear fusion power plants: a computational analysis of hollow nanoparticles

“…In the case of ICF with direct-drive targets, shrapnel is not a concern, but the buffer gas is incompatible with target cryogenics during injection [11]. Alternative solutions [12] have been proposed, such as magnetic intervention [13] or wetted wall concepts [14,15]. Many years after the first proposals of wetted walls [16], aspects like the formation of aerosols, the vapour pressure inside the chamber or the maintenance of a liquid layer over all the internal surfaces of the chamber remain unaddressed [17], despite their paramount importance for this approach.…”

Recent progress of the JT-60SA project

“…The principle of the Japanese fusion research and development activities is laid down in the 'Third Phase Basic Program of Fusion Research and Development' [8] formulated by the Atomic Energy Commission in Japan, which was released in June 1992. The achievement of the self-ignition condition, the demonstration of long pulse (1000 s) burning plasma and the development of fundamental fusion technology necessary for DEMO are the main targets.…”