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
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Feb 2026
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
February 2026
Nuclear Technology
January 2026
Fusion Science and Technology
Latest News
DOE announces NEPA exclusion for advanced reactors
The Department of Energy has announced that it is establishing a categorical exclusion for the application of National Environmental Policy Act (NEPA) procedures to the authorization, siting, construction, operation, reauthorization, and decommissioning of advanced nuclear reactors.
According to the DOE, this significant change, which goes into effect today, “is based on the experience of DOE and other federal agencies, current technologies, regulatory requirements, and accepted industry practice.”
T. Cho et al. (17R03)
Fusion Science and Technology | Volume 51 | Number 2 | February 2007 | Pages 11-16
Technical Paper | Open Magnetic Systems for Plasma Confinement | doi.org/10.13182/FST07-A1305
Articles are hosted by Taylor and Francis Online.
(1) Four-time progress in ion-confining potentials c to 3.0 kV in comparison to c attained 1992-2002 is achieved in the hot-ion mode (Ti=several keV). A scaling of c, which favorably increases with plug electron-cyclotron heating (ECH) powers (PPECH), is obtained. (2) The advance in c leads to a finding of remarkable effects of radially sheared electric fields (dEr/dr) on turbulence suppression and transverse-loss reduction. (3) A weak decrease in c with increasing nc to ~1019 m-3 with the recovery of c with increasing PPECH is obtained. (4) The first achievement of active control and formation of an internal transport barrier (ITB) has been carried out with the improvement of transverse energy confinement. Off-axis ECH in an axisymmetric barrier mirror produces a cylindrical layer with energetic electrons, which flow through the central cell and into the end region. The layer, which produces a localized bumped ambipolar potential c, generates a strong Er shear and peaked vorticity with the direction reversal of Err × B sheared flow near the c peak. Intermittent vortex-like turbulent structures near the layer are suppressed in the central cell. This results in Te and Ti rises surrounded by the layer. The phenomena are analogous to those in tokamaks with ITB. (5) Preliminary central ECH (170 kW, 20 ms) in a standard tandem-mirror operation raises Te0 from 70 to 300 eV together with Ti[perpendicular]0 from 4.5 to 6.1 keV, and Ti//0 from 0.5 to 1.2 keV with p0=95 ms for c (=1.4 kV) trapped ions. The on-axis particle to energy confining ratio of p0/E0 is observed to be 1.7 for c trapped ions (consistent with Pastukhov's theory) and 2.4 for central mirror-trapped ions with 240-kW plug ECH and 90-kW ICH (ICH~0.3; nlc=4.5×1017 m-2). (6) Recently, a 200 kW central ECH with 430 kW plug ECH produces stable central-cell plasmas (Te=600 eV and Ti=6.6 keV) with azimuthal Er×B sheared flow. However, in the absence of the shear flow, hot plasmas migrate unstably towards vacuum wall with plasma degradation.
