Fusion Science and Technology -- ANS / Publications / Journals / Fusion Science and Technology

About ANS
- ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
About Nuclear
- Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Communities
- Division Spotlight
  Nuclear Nonproliferation Policy
  The mission of the Nuclear Nonproliferation Policy Division (NNPD) is to promote the peaceful use of nuclear technology while simultaneously preventing the diversion and misuse of nuclear material and technology through appropriate safeguards and security, and promotion of nuclear nonproliferation policies. To achieve this mission, the objectives of the NNPD are to: Promote policy that discourages the proliferation of nuclear technology and material to inappropriate entities. Provide information to ANS members, the technical community at large, opinion leaders, and decision makers to improve their understanding of nuclear nonproliferation issues. Become a recognized technical resource on nuclear nonproliferation, safeguards, and security issues. Serve as the integration and coordination body for nuclear nonproliferation activities for the ANS. Work cooperatively with other ANS divisions to achieve these objective nonproliferation policies.
Events
- Meeting Spotlight
  ANS Student Conference 2025
  April 3–5, 2025
  Albuquerque, NM|The University of New Mexico
Standards
- 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!
Publications
- Latest Magazine Issues
  Apr 2025
  Jan 2025
  Latest Journal Issues
  Nuclear Science and Engineering
  May 2025
  Nuclear Technology
  April 2025
  Fusion Science and Technology
  April 2025
- Latest News
  General Kenneth Nichols and the Manhattan Project
  Nichols
  The Oak Ridger has published the latest in a series of articles about General Kenneth D. Nichols, the Manhattan Project, and the 1954 Atomic Energy Act. The series has been produced by Nichols’ grandniece Barbara Rogers Scollin and Oak Ridge (Tenn.) city historian David Ray Smith. Gen. Nichols (1907–2000) was the district engineer for the Manhattan Engineer District during the Manhattan Project.
  As Smith and Scollin explain, Nichols “had supervision of the research and development connected with, and the design, construction, and operation of, all plants required to produce plutonium-239 and uranium-235, including the construction of the towns of Oak Ridge, Tennessee, and Richland, Washington. The responsibility of his position was massive as he oversaw a workforce of both military and civilian personnel of approximately 125,000; his Oak Ridge office became the center of the wartime atomic energy’s activities.”
Search

The plasma and machine parameters of a pulsed tokamak reactor with a day-long operation period have been studied, where engineering constraints such as maximum toroidal field strength are preserved at International Thermonuclear Experimental Reactor (ITER) levels so as to realize a fusion reactor with only a short-range extension of currently available technology. To provide the magnetic flux necessary to sustain a plasma current inductively for 1 day or longer, plasmas with a major radius of R > 9.5 m are necessary, and a plasma with an aspect ratio as high as A > 5 should be employed. Typical parameters are as follows: major radius R = 10 m, minor radius a = 1.85 m, plasma elongation κ = 1.8, plasma current I_p = 12.2MA, toroidal field on axis B_t >= 7.56 T, and safety factor at the plasma surface q_ψ = 3. A plasma volume V ∼ 1200 m³ is comparable with that of ITER, even though the major radius of a day-long operation reactor is relatively large. A very small amount of heating power (∼ 15 MW) with a heating time of only a few tens of seconds is sufficient to achieve the ignition condition. This is well within the capacity of auxiliary heating systems currently used in large tokamak devices. A confinement improvement factor (from L mode) of f_L > 1.7 is required to design a reactor with a reasonable machine size and a day-long pulse duration. The operation temperature is chosen to be 〈T〉 = 20 keV with a toroidal beta β_t = 2.6% (Troyon factor g = 3), which gives a fusion power P_fus = 2.5 GW even for an alpha-particle dilution n_α/n_e of 10%. The bootstrap current fraction is 50% or more of the total current, and current profile needed for the beta limit could be achieved with a combination ofohmic current in the plasma center region and bootstrap current in the outer region. If the maximum toroidal field is set much higher, as in proposed recent reactor designs for the Steady-State Tokamak Reactor (SSTR) and ARIES, a more attractive plasma with a larger safety factor can be designed, and the pulse length can be extended remarkably.