Structural Design for ITER Gas Injection System Gas Fueling Gas Valve Box
FUSION SCIENCE AND TECHNOLOGY
Authors: Xia, Z. W.; Li, W.; Liu, X. G.; Huang, X. M.; Pan, Y. D.; Liu, S.; Jiang, T.; Li, B.; Maruyama, S.; Yang, Y.; Kiss, G.; Kruezi, U.
Abstract
The ITER gas injection system delivers gases from the tritium plant to the vacuum vessel, fueling pellet injection system, and neutral beam for plasma operation and fusion power shutdown. In this system, the gas fueling (GF) gas valve box (GVB) is an indispensable part that mainly provides functions of gas throughput control and measurement of gas pressure, flow rate, and temperature. The preliminary structure design is largely driven by the requirements of magnetic field compatibility and limited integration space. A strong magnetic field of over 0.2 T exists around the GVB locations, so a magnetic shielding design is required to ensure the normal function of susceptible components. Instead of the previous overall shielding, a local magnetic shielding has been developed by a validated analysis method. As a result, the total weight of the shield has been reduced from over 7000 kg to about 200 kg. Furthermore, considering the limited space reservation, a highly compact flat layout for the GF GVB has been developed to ensure enough maintenance space in front of it. In addition, other requirements such as structure integrity under various load combinations, leak detectability, in situ maintainability, etc., have all been taken into account.
Combining rival -space descriptions of O-3 and of SO2
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
Authors: Penotti, Fabio E.; Cooper, David L.
Abstract
Two rival solutions have emerged from applications of spin-coupled (SC) theory, also known as the full-generalized valence bond (full-GVB) approach, to the system of O-3. The lowest solution (SCd) corresponds to significant diradical character but there is a second solution (SCc) which lies fairly close in energy. Combining these two descriptions, it turns out that both of them make significant contributions, with neither being dominant. The situation is entirely different for SO2, with the SCc description being overwhelmingly dominant over SCd. It can be concluded from an examination of various combinations of rival -space descriptions for both molecules that neither of the SCc nor SCd solutions provides a very satisfactory description on its own of the system in O-3, but that SO2 is already fairly well described by SCc before the explicit incorporation of any SCd character. (c) 2016 Wiley Periodicals, Inc.