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.
Lucas P. Tucker, Shoaib Usman, Ayodeji Alajo
Nuclear Technology | Volume 194 | Number 1 | April 2016 | Pages 97-110
Technical Paper | doi.org/10.13182/NT15-67
Articles are hosted by Taylor and Francis Online.
The Missouri University of Science and Technology Subcritical Assembly has been brought back into service and upgraded with a new neutron detection system and Internet accessibility. Before the upgrade, neutron counting was possible in only one location. Using a movable detection system housed in acrylic tubes, measurements can now be taken in any empty fuel location and at any height within the tube, making three-dimensional flux mapping possible. By connecting the new detection system to a Canberra Lynx Digital Signal Analyzer, remote users can have limited data-collecting capabilities. To further enhance the potential of the facility, a Monte Carlo N-Particle transport code (MCNP) model of the subcritical assembly was created and validated by comparing its simulated predictions to experiments conducted at the facility. An approach to the criticality experiment using the 1/M approximation showed that the MCNP model accurately predicts keff if the detectors are placed between 27 and 36 cm from the neutron source. The results of an axial flux measurement experiment taken 20.3 cm from the neutron source differed from the MCNP-simulated results by an average of 12%. Finally, the validated MCNP model was used to show the effect of removing the facility’s fixed detector tube and redistributing its fuel. MCNP simulation predicts that the new configuration would increase the multiplication factor from 0.73481 ± 0.00008 to 0.76844 ± 0.00004.
