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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.
Sherly Ray, R. S. Modak
Nuclear Science and Engineering | Volume 170 | Number 1 | January 2012 | Pages 75-86
Technical Note | doi.org/10.13182/NSE10-87TN
Articles are hosted by Taylor and Francis Online.
Numerical evaluation of the steady-state neutron flux distribution in a slightly subcritical nuclear reactor due to the presence of a fixed external source is considered by using neutron diffusion theory. It has been shown in the literature that in the particular case when keff is very close to unity (say, within 1 mk), many solution techniques face severe convergence problems. In this context, an acceleration method called Accelerated SubCritical Multiplication (ASCM), originally suggested in the well-known neutron transport code TORT, is investigated in this paper specifically for such cases. The studies are based on a realistic heavy water reactor test case analyzed by two-group diffusion theory. ASCM is found to work very well. It is useful even when the distributions of the external source and the fission source are vastly different. ASCM is based on iterative scaling of the overall flux level in the reactor. An alternative way to evaluate the “scaling factor” is discussed. A somewhat new ASCM-like scheme is suggested to accelerate the Jacobi and Gauss-Seidel iterations needed for the within-group calculations. Conditions for the effectiveness of this scheme are discussed. Implications of the present work in reactor kinetics and some other fields are indicated.
