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Conference Spotlight
2026 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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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.
Weston M. Stacey, Jr.
Nuclear Science and Engineering | Volume 48 | Number 4 | August 1972 | Pages 444-458
Technical Paper | doi.org/10.13182/NSE72-A22512
Articles are hosted by Taylor and Francis Online.
A variational theory is developed for estimating reactivity worths (and other bilinear ratios) and reaction rate ratios in critical nuclear reactors. These estimates embody corrections to first-order perturbation theory which account for the flux change caused by the reactivity perturbation and for the changes in the flux and adjoint when the system is altered. The physical significance of certain generalized functions which arise in the development of the theory is investigated. The relation of the variational theory to generalized perturbation theory is examined, and the additional restrictions required to reduce the former to the latter are established. Finally, the variational theory is demonstrated to yield accurate estimates for reactivity worths and reaction rate ratios in a fast reactor model, subject to a wide range of alterations in nuclear properties and compositions.
