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Conference Spotlight
2026 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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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!
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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.
Nelson Jarmie
Nuclear Science and Engineering | Volume 78 | Number 4 | August 1981 | Pages 404-412
Technical Note | doi.org/10.13182/NSE81-A21375
Articles are hosted by Taylor and Francis Online.
We investigated the accuracy of the basic fusion data for the T(d, n)4He, 3He(d, p)4He, T(t, 2n)4He, D(d, n)3He, and D(d, p)T reactions in the 10- to 100-keV bombarding energy region, and assessed the effects of inaccuracies on the design of fusion reactors. The data base for these reactions /particularly the most critical T(d, n)4He reaction/ rests on 25-yr-old experiments whose accuracy (often assumed to be ±5%) has rarely been questioned: Yet, in all except the D + D reactions, there are significant differences among data sets. The errors in the basic data sets may be considerably larger than previously expected, and the effect on design calculations should be significant. Much of the trouble apparently lies in the accuracy of the energy measurements, which are difficult at low energies. Systematic errors of up to 50% are possible in the reactivity values of the present T(d, n)4He data base. The errors in the reactivity will propagate proportionally into the errors in fusion probabilities in reactor calculations. The 3He(d, p)4He reaction cross sections could be in error by as much as 50% in the low-energy region. The D(d, n)3He and D(d, p)T cross sections appear to be well known and consistent. The T(t, 2n)4He cross section is poorly known and may be subject to large systematic errors. Improved absolute measurements for all the reactions in the low bombarding energy region (10 to 100 keV) are needed, but until they are done, the data sets should be left as they are [except for T(t, 2n)4He data, which could be lowered by ∼50%]. The apparent uncertainties of these data sets should be kept in mind.
