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Division Spotlight
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
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!
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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.
J. Chernick, S. Oleksa Moore
Nuclear Science and Engineering | Volume 6 | Number 6 | December 1959 | Pages 537-544
doi.org/10.13182/NSE59-A15516
Articles are hosted by Taylor and Francis Online.
The breeding potential of thermal reactors is re-evaluated on the basis of present nuclear data. It is concluded that positive breeding on the U233, thorium cycle is possible with a variety of moderators including heavy water, graphite, beryllium, and ordinary water. Current measurements indicate that the accepted thermal value of η23 = 2.28 ± 0.02 is somewhat conservative. Neutron spectrum considerations show that η23 decreases gradually with increasing resonance absorption to a minimum of 2.14 ± 0.04. When neutron losses to the moderator are considered, maximum breeding gains of 0.26, 0.22, 0.21, and 0.19, respectively, are obtained for D2O, graphite, Be, and H2O moderated reactors. The breeding gain in reactors partially or completely moderated by beryllium can be considerably increased if use is made of the fast effect, presently estimated at 1.075 ± 0.02 for pure beryllium. Probable breeding gains in proposed full-scale fluid fuel breeders are estimated at 0.09 for the Aqueous Homogenous Reactor and 0.05 for the graphite moderated Liquid Metal Fuel Reactor and Molten Salt Reactor. Breeding in predominantly thermal, solid fuel reactors also appears within reach if neutron losses are minimized. The possibility of positive breeding in near thermal, plutonium fuelled reactors is unsettled although this goal can be approached by maximum use of the fast effect in U238. Estimates of breeding ratios in plutonium fuelled reactors depends on the variation of η49 with neutron temperature which is still inadequately known.