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.
Division Spotlight
Aerospace Nuclear Science & Technology
Organized to promote the advancement of knowledge in the use of nuclear science and technologies in the aerospace application. Specialized nuclear-based technologies and applications are needed to advance the state-of-the-art in aerospace design, engineering and operations to explore planetary bodies in our solar system and beyond, plus enhance the safety of air travel, especially high speed air travel. Areas of interest will include but are not limited to the creation of nuclear-based power and propulsion systems, multifunctional materials to protect humans and electronic components from atmospheric, space, and nuclear power system radiation, human factor strategies for the safety and reliable operation of nuclear power and propulsion plants by non-specialized personnel and more.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
June 2025
Nuclear Technology
Fusion Science and Technology
May 2025
Latest News
Argonne’s METL gears up to test more sodium fast reactor components
Argonne National Laboratory has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop), the Department of Energy announced April 23. The upgrade is the first of its kind in the United States in more than 30 years, according to the DOE, and will help test components and operations for the sodium-cooled fast reactors being developed now.
Dong H. Nguyen, Lawrence M. Grossman
Nuclear Science and Engineering | Volume 30 | Number 2 | November 1967 | Pages 233-241
Technical Paper | doi.org/10.13182/NSE67-A17334
Articles are hosted by Taylor and Francis Online.
The space-dependent ion production rate by fission fragments escaping from a fuel plate is studied using: 1) the Bohr stopping equation with the Thomas-Fermi approximation of the effective charge Zeff; 2) the Alexander-Gazdik (A-G) semiempirical velocity-distance relationship for fission fragments. The assumptions are: a) no scattering during slowing down; b) the nonionizing energy loss in nuclear recoils can be taken into account by increasing the w value for fission fragments over that for α particles; c) a delta-function mass distribution for the light and heavy group; and d) a monoenergetic source. The energy current carried by the fragments at a point in the outer medium is first derived, and the energy deposition per unit volume per second is obtained by taking the gradient of the energy current. Dividing the energy deposition by the w value for the medium yields the ion production rate by fission fragments in that medium. The results show that the semiempirical velocity-distance relationship gives a higher ion production rate than that given by the velocity-distance relationship derived from the Bohr stopping equation with the Thomas-Fermi approximation of the effective charge Zeff. The volumetric, spatial average ion production rate is also obtained. For a fuel plate containing 20% 235U and 80% Pt and for a flux of 6 × 1010 n/(cm2 sec), the velocity-distance relationship based on the Bohr stopping equation gives an average ion production rate of 2.0 × 1013 ion pairs/(cm3 sec) in a mixture Ne + 0.1% Ag. Using the same values for the fragment ranges, the semiempirical velocity-distance relationship yields an average volumetric ion production rate in neon higher by about 18% for the light fragment and by about 20% for the heavy fragment. According to existing experimental results on plasmas induced by fission fragments, an ion source of 2.0 × 1013 ion pairs/(cm3 sec) would yield a conductivity of about 1 × 10−3 (Ωm)−1 in the gas mixture Ne + 0.1% Ag, at 200-mm Hg and 400 °K and at an electric field of 560V/m.
