ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Oct 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
November 2025
Nuclear Technology
October 2025
Fusion Science and Technology
Latest News
NRC nominee Nieh commits to independent safety mission
During a Senate Environment and Public Works Committee hearing today, Ho Nieh, President Donald Trump’s nominee to serve as a commissioner at the Nuclear Regulatory Commission, was urged to maintain the agency’s independence regardless of political pressure from the Trump administration.
M. Seki, Y. Ikeda, S. Maebara, S. Moriyama, O. Naito, K. Anno, S. Hiranai, M. Shimono, S. Shinozaki, M. Terakado, K. Yokokura, T. Yamamoto, T. Fujii
Fusion Science and Technology | Volume 42 | Number 2 | September-November 2002 | Pages 452-466
Technical Paper | doi.org/10.13182/FST02-A240
Articles are hosted by Taylor and Francis Online.
Development and operation of a lower hybrid range of frequency (LHRF) system for JT-60U are presented. The LHRF system was constructed in 1986 to study current drive and plasma heating at high injection power. Its main specifications are the total output power 24 MW with 24 high power klystrons, the frequency 1.74 to 2.23 GHz, and the injection power ~10 MW with three conventional antennas. To improve the antenna capabilities such as the current drive efficiency, N//peak controllability and the power injection properties, a 3-divided multi-junction type (CD1' launcher) and a 12-divided multi-junction type (CD2 launcher) are developed. The CD2 launcher can also reduce the number of the transmission lines to one fourth of the original system. The injection power ~7 MW is attained, and then the highest current drive efficiency 3.5 × 1019 m-2AW-1 and the highest non-inductive driven current 3.6 MA are achieved. The high power klystron capable of the cathode-heater operation times more than 3000 hours is improved. The outgassing rate is estimated with the CD2 launcher as 1-10 × 10-6 Pam3/sm2, which is sufficiently small not to need the vacuum pumping system for the launcher. Heat load onto the launcher due to the ripple enhanced banana drift loss is first observed in NBI or ICRF heating. From investigation on antenna-plasma coupling, the gas puffing improves distant coupling.
