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
Nuclear Installations Safety
Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
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.
Yasuki Kowata, Nobuo Fukumura
Nuclear Science and Engineering | Volume 127 | Number 1 | September 1997 | Pages 89-103
Technical Paper | doi.org/10.13182/NSE97-A1923
Articles are hosted by Taylor and Francis Online.
Plutonium fuel could be utilized in the entire core of a heavy water-moderated, boiling light water-cooled pressure-tube-type reactor (HWR). The coolant void reactivity, however, depends on the various parameters of the lattice. It is especially significant to clarify the effect of plutonium nuclides on the void reactivity.The void reactivities in the infinite HWR lattices have been parametrically analyzed to clarify the effects of changes in the lattice parameters on the void reactivity using the WIMS-D4 code with the JENDL-3.1 nuclear data. At present, it is known that the behavior of the void reactivity can be clarified by separating the components of fuel nuclides, neutron cross sections, energy groups, and regions in the lattice cell from the global reactivity effect, using the important reaction rates.If the fuels are the same in the macroscopic absorption cross section for the 2200 m/s neutron, it has been shown that the void reactivity shifts further to a negative direction in a narrower pitch lattice and in the plutonium-fueled lattice with a higher content of 239Pu rather than in the uranium one. The effect of reducing the void reactivity to the negative by fissile plutonium is caused mainly by the presence of the resonance cross section at ~0.3 eV of 239Pu. The higher the content of 239Pu, the less the recovery of dipped neutron flux within the resonance energy width due to a decrease in the thermal neutron scattering of hydrogen with an increase in coolant void fraction, so that the decreased resonance fission rate for 239Pu contributes to the more negative direction for the void reactivity.On the other hand, resonance at ~0.3 eV for 241Pu does not have an important role for the void reactivity because its resonance cross section is smaller than that of 239Pu.