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
Fusion Energy
This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
Meeting Spotlight
2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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
Aug 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
October 2024
Nuclear Technology
Fusion Science and Technology
August 2024
Latest News
New laws offer nuclear industry incentives for existing power plant uprates
This year, the U.S. nuclear industry received a much-needed economic boost that could help preserve operating nuclear power plants and incentivize upgrades that extend their lifespan and power output.
Signed into law in 2022, the Inflation Reduction Act offers production tax credits (PTCs) for existing nuclear power plants and either PTCs or investment tax credits (ITCs) for new carbon-free generation. These credits could make power uprates—increasing the maximum power level at which a commercial plant may operate—a much more appealing option for utilities.
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.
