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Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
Nermin A. Uckan
Fusion Science and Technology | Volume 21 | Number 3 | May 1992 | Pages 1444-1448
International Thermonuclear Experimental Reactor | doi.org/10.13182/FST92-A29924
Articles are hosted by Taylor and Francis Online.
The ranges of confinement-relevant (dimensional and dimensionless) plasma parameters for major tokamaks (JET, JT-60U, TFTR, DIII-D, …) that are expected to contribute to the ITER Physics R&D in the 1990s have been analyzed to characterize confinement and plasma performance in ITER-like designs. We find that the largest tokamaks (JET, JT-60U) should be able to demonstrate H-mode operation (with ELMs, as in ITER) with nτETi values within an order of magnitude of those required in ITER and have relevant dimensionless plasma parameters (ρ/a, ν*, etc.) within a factor 2 of those in ITER. Extrapolations from dimensionally similar discharges in DIII-D and JET show high-Q/ignition operation in ITER-like plasmas at plasma currents (∼16 MA) well below the nominal (22-MA) design value. Another critical issue for achieving ignition-level plasma performance is the anomalous alpha particle effects, mainly the “toroidal Alfvén eigenmode” (TAE mode). The D-T experiments in TFTR and JET (and simulations using fast beam ions) should realize alpha particle (fast-ion) parameters roughly similar, in relation to TAE mode thresholds, to those projected for ITER. We judge that present-day tokamaks will provide a sufficient database (by the mid-1990s) on H-mode confinement (with ELMs) and possible anomalous alpha particle effects at relevant dimensionless parameters that are expected to be adequate for ITER purposes.
