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
January 2026
Nuclear Technology
December 2025
Fusion Science and Technology
November 2025
Latest News
What’s the most difficult question you’ve been asked as a maintenance instructor?
Blye Widmar
"Where are the prints?!"
This was the final question in an onslaught of verbal feedback, comments, and critiques I received from my students back in 2019. I had two years of instructor experience and was teaching a class that had been meticulously rehearsed in preparation for an accreditation visit. I knew the training material well and transferred that knowledge effectively enough for all the students to pass the class. As we wrapped up, I asked the students how they felt about my first big system-level class, and they did not hold back.
“Why was the exam from memory when we don’t work from memory in the plant?” “Why didn’t we refer to the vendor documents?” “Why didn’t we practice more on the mock-up?” And so on.
J. G. Carver, W. R. Morgan, C. R. Porter, M. A. Robkin
Nuclear Science and Engineering | Volume 41 | Number 2 | August 1970 | Pages 209-225
Technical Paper | doi.org/10.13182/NSE70-A20708
Articles are hosted by Taylor and Francis Online.
Measurements have been made of relative nuclear-reaction rates within sub-critical water-moderated plutonia-urania fuel lattices, under conditions considered typical for plutonium recycle in central-station power reactors. Measurement conditions included water:fuel ratios of 3:1 and 2:1; temperatures of 70, 235, 330, 430, and 540°F; and three positions within the unit cell. Nuclear reaction rates measured included relative fission rates in 235U, 239Pu, and 241Pu, as well as relative capture rates in 176Lu (principal resonance at 0.143 eV), 168Yb (0.597 eV), 191Ir (0.654 eV), 193Ir (1.303 eV), 197Au (4.906 eV), 139La (73.5 eV), and 63Cu (1/v detector). To facilitate comparison with predicted values, the experimental resonance absorption-rate ratios were normalized to ratios measured within a pure water spectrum. Experimental reaction-rate ratios were compared with values predicted using the THERMØS code in conjunction with a modified version of EPITHERMØS; and agreement varying from fair to good was observed. The internal consistency of the measurements suggests their future utility for evaluating methods of calculating neutron spectra and relative reaction rates within lattices of the type considered.
