Design analysis to reduce the equivalent dose rate of the neutral beam injection system in a fusion experimental reactor

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · Fusion Technology

OSTI ID:380831

Shibata, Kei-Ichiro; Maki, Koichi; Otsuka, Michio ^[1]; Inoue, Takashi ^[2]

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1. Hitachi, Ltd., Ibaraki (Japan)
2. Japan Atomic Energy Research Inst., Ibaraki (Japan)

As applied to the common design of the neutral beam injection (NBI) system in the International Thermonuclear Experimental Reactor (ITER) Conceptual Design Activity, a design is proposed and examined that reduces the equivalent dose rate of the NBI system in order to enable access to the outside of the injector. Modifying the current system is necessary because the equivalent dose rate in the NBI room after reactor shutdown is higher than the design limit for radiation workers. The NBI maintenance concept is based on full-remote maintenance. There are, however, some problems that must be solved before full-remote maintenance could be realized - such as connection and disconnection of the electric power cables and complicated coolant pipes, and location of the maintenance equipment - this concept solves the aforementioned problem by enabling worker accessibility to the outside of the injector. The following design points are suggested to reduce the equivalent dose rate. The vacuum vessel should be composed of aluminum to reduce the induced radioactivity. Polyethylene, which has high shielding ability for neutrons, should be installed between the vessel and magnetic shield located outside the vacuum vessel to reduce not only neutron flux coming to the magnetic shield but also gamma-ray flux, caused by in-vessel components, leaking to the NBI room. 18 refs., 11 figs., 3 tabs.

• OSTI ID: 380831
• Journal Information: Fusion Technology, Journal Name: Fusion Technology Journal Issue: 1 Vol. 30; ISSN FUSTE8; ISSN 0748-1896
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
99 GENERAL AND MISCELLANEOUS
ALUMINIUM
DESIGN
DOSE EQUIVALENTS
DOSE RATES
ITER TOKAMAK
NEUTRAL ATOM BEAM INJECTION
NEUTRON FLUX
NEUTRON SPECTRA
PERMALLOY
POLYETHYLENES
RADIATION DOSES
RADIOACTIVITY
REACTOR COMPONENTS
REDUCTION
SHIELDING
STAINLESS STEELS
THERMONUCLEAR REACTORS