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.
Explore membership for yourself or for your organization.
Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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
Sep 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
October 2025
Nuclear Technology
September 2025
Fusion Science and Technology
Latest News
U.K.’s NWS gets input from young people on geological disposal
Nuclear Waste Services, the radioactive waste management subsidiary of the United Kingdom’s Nuclear Decommissioning Authority, has reported on its inaugural year of the National Youth Forum on Geological Disposal forum. NWS set up the initiative, in partnership with the environmental consultancy firm ARUP and the not-for-profit organization The Young Foundation, to give young people the chance to share their views on the government’s plans to develop a geological disposal facility (GDF) for the safe, secure, and long-term disposal of radioactive waste.
Claude Mounier, Pietro Mosca
Nuclear Science and Engineering | Volume 179 | Number 2 | February 2015 | Pages 130-147
Technical Paper | doi.org/10.13182/NSE13-63
Articles are hosted by Taylor and Francis Online.
The fast neutron fluence is an important parameter for the reactor pressure vessel (RPV) lifetime. The uncertainty estimation of this parameter is crucial to manage the RPV with a suitable safety margin. This work focuses on a facet of the problem that concerns the uncertainty contribution of the spectrum of the fission source for different burnups in a thermal neutron reactor. The main goal of this paper is to assess the effect of a possible uncertainty correlation among the spectra of the fissile nuclei, involved in the fission source, on the response uncertainty. Two main simplifications are assumed to reduce the complexity of the problem. The first simplification concerns the geometry of the transport problem that is chosen to calculate as fast as possible the sensitivities and the different responses. The second simplification is related to the way by which one can take into account the correlations among spectra of different fissile nuclei. Simple ENDF-6 models of the fission spectrum (Maxwell, Watt, and simplified Madland-Nix) are used to define correlations among the fissile spectra through the mean neutron energy of the prompt fission spectrum. Results are given to quantify the effect of these postulated correlations on response uncertainties and are compared to the ones using JENDL-4.0 covariances.