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
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Mar 2026
Jan 2026
Latest Journal Issues
Nuclear Science and Engineering
April 2026
Nuclear Technology
February 2026
Fusion Science and Technology
Latest News
Swiss nuclear power and the case for long-term operation
Designed for 40 years but built to last far longer, Switzerland’s nuclear power plants have all entered long-term operation. Yet age alone says little about safety or performance. Through continuous upgrades, strict regulatory oversight, and extensive aging management, the country’s reactors are being prepared for decades of continued operation, in line with international practice.
Jae-Woong Song, Jong-Kyung Kim
Nuclear Technology | Volume 103 | Number 2 | August 1993 | Pages 157-167
Technical Paper | Fission Reactor | doi.org/10.13182/NT93-A34840
Articles are hosted by Taylor and Francis Online.
An efficient nodal method for the solution of two-group, multidimensional neutron kinetics problems is presented. In this method, correction factors called discontinuity factors are calculated in advance by the nodal expansion method (NEM) at steady-state conditions, and the nodewise flux and power distributions during steady-state and transient conditions are calculated based on the discontinuity factors. The nodal balance equation using the discontinuity factors is expressed logically in a less complicated manner than in other nodal methods since the factors reflect all of the approximations, including classic spatial truncations. Additionally, the convergence of the transient problem can be greatly accelerated through a thermal leakage-to-absorption ratio (TLAR) scheme. The test results for the two-group, two-dimensional benchmark problems demonstrate that this new method has acceptable accuracy and is about two times faster without the TLAR scheme and about ten times faster with the TLAR scheme than other nodal methods (NEM or analytic nodal method) for transient applications in which assemblysize coarse nodes are used.