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 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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
Dec 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
December 2025
Nuclear Technology
Fusion Science and Technology
November 2025
Latest News
Modernizing I&C for operations and maintenance, one phase at a time
The two reactors at Dominion Energy’s Surry plant are among the oldest in the U.S. nuclear fleet. Yet when the plant celebrated its 50th anniversary in 2023, staff could raise a toast to the future. Surry was one of the first plants to file a subsequent license renewal (SLR) application, and in May 2021, it became official: the plant was licensed to operate for a full 80 years, extending its reactors’ lifespans into 2052 and 2053.
Dağıstan Şahin, Kenan Ünlü, Kostadin Ivanov
Nuclear Technology | Volume 194 | Number 3 | June 2016 | Pages 324-339
Technical Paper | doi.org/10.13182/NT15-110
Articles are hosted by Taylor and Francis Online.
The main goal of this study is to verify the accuracy of burnup-coupled neutronic calculations when employing the Monte Carlo Utility for Reactor Evolutions (MURE) and MCNP5 codes for modeling TRIGA-type reactors, in this case the Penn State Breazeale Reactor (PSBR) core. Research and educational requirements mainly direct the PSBR operating schedule. With such operating schedules, one particular area of concern, specifically relating to nuclear analytical applications, is time-dependent changes in the neutronic characteristics of the reactor, specifically within the irradiation positions. Particular concern exists among scientists performing neutron activation analysis measurements as to whether continuous variations in reactor operations would cause significant fluctuations in the neutronic characterization parameters of the irradiation positions. A secondary objective of this study is to analyze fluctuations in the neutronic characterization parameters and their dependence on various core conditions as examined by detailed burnup-coupled neutronic simulations. In this study, a burnup-coupled neutronic simulation model of the PSBR is developed using the MURE and MCNP5 codes. The simulation results are verified by a series of experiments including measurements of the core excess reactivity starting from the first core loading in 1965 to 2012, control rod worth, fission product buildup, temperature-dependent reactivity loss, integral control rod worth curves, individual fuel element worth, and neutron flux. Local neutronic calculations of the simulation are confirmed by measuring neutronic characterization parameters for one of the irradiation positions within the PSBR core, namely, dry irradiation tube 1. Analyzing time-dependent data predicted by the simulation, the neutron temperature and the measure of the nonideal epithermal neutron flux distribution are found to be reasonably static. Conversely, the thermal-to-epithermal neutron flux ratio and spectral index are found to be relatively responsive to alterations in the core.
