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Atlanta, GA|Atlanta Marriott Marquis
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Latest News
The Frisch-Peierls memorandum: A seminal document of nuclear history
The Manhattan Project is usually considered to have been initiated with Albert Einstein’s letter to President Franklin Roosevelt in October 1939. However, a lesser-known document that was just as impactful on wartime nuclear history was the so-called Frisch-Peierls memorandum. Prepared by two refugee physicists at the University of Birmingham in Britain in early 1940, this manuscript was the first technical description of nuclear weapons and their military, strategic, and ethical implications to reach high-level government officials on either side of the Atlantic. The memorandum triggered the initiation of the British wartime nuclear program, which later merged with the Manhattan Engineer District.
N. Hosogane, the JT-60 Team, JFT-2M Group
Fusion Science and Technology | Volume 47 | Number 3 | April 2005 | Pages 363-369
Technical Paper | Fusion Energy - Experimental Devices and Advanced Designs | doi.org/10.13182/FST05-A717
Articles are hosted by Taylor and Francis Online.
For steady state advanced tokamak research with long pulse operations, JT-60U tokamak discharge, NBI and RF heating injection durations have been extended from 15 s to 65 s and from 10 s to 30 s respectively mainly by means of modifying their control systems and using derated power levels. In addition, technological issues for their long pulse injections with the heating systems have been solved as follows. The ion source of the negative ion NBI system was modified to increase gas conductance in the accelerator, which reduced the heat load to the grounded grid due to stripping loss to a level that enables operations of 2 MW for 30 s. A new method of controlling the anode voltage has been developed for sustaining the oscillation condition of a gyrotron in the electron cyclotron (EC) system. With this method, the EC injection duration has reached 16 s at 0.4 MW. To avoid serious damage of the LH launcher, a heat-resistant carbon grill LH antenna was implemented on the original stainless steel grill. To date, the advanced tokamak operations have been extended to N = 2.1 for 20 s. In JFT-2M, high N plasmas had been investigated with the vacuum vessel covered with ferritic steels. N of ~3.5 was obtained with rwall/a~1.3-1.6 without serious influence of ferromagnetic walls (rwall is distance of the wall from a plasma center and a is minor radius of a plasma). This encourages the utilization of ferric steel as a structural material for future reactors.
