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Division Spotlight
Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
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2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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!
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Nuclear new build procurement considerations
It may seem counterintuitive, but the best time to enhance the ability to support operations and maintenance for a new plant is before construction starts. This is one of many lessons learned by the currently operating nuclear fleet. As construction and startup of many nuclear facilities was completed, it quickly became evident that the ability to efficiently support operations and maintenance was limited. Most of the information necessary to establish and manage procurement of spare and replacement items, maintenance, and configuration of the facilities was unavailable and had to be gathered on a case-by-case, “on-demand” basis. Absence of necessary information and the associated challenges resulted in the need for staff augmentation and multiyear-long projects to develop equipment bills of material and maintenance programs and to perform technical evaluations for the huge quantities of spare and replacement items being requested.
Louis M. Shotkin
Nuclear Technology | Volume 117 | Number 1 | January 1997 | Pages 40-48
Technical Paper | Fission Reactor | doi.org/10.13182/NT97-A35334
Articles are hosted by Taylor and Francis Online.
Almost 20 yr ago, the U.S. Nuclear Regulatory Commission (NRC) thermal-hydraulic code development effort made the transition from a homogeneous equilibrium formulation to a two-fluid formulation. The objective was to introduce a more physically based model so that the code analyst would have to make fewer choices in the input deck to simulate expected phenomena. There were still several options left open to the user, especially the noding for the simulation. Recent experience with NRC analyses, as well as with International Standard Problems, has shown that there can still be a considerable “user effect” in the use of even the two-fluid codes. Two specific examples are given. Using the RELAP5 code as a specific prototype to focus the discussion, examples are given of the choices currently available to the analyst. Similar choices are available in almost all thermal-hydraulic system codes. These example choices serve to show that even though thermal-hydraulic system codes are reaching a certain state of maturity, the user must still make many choices in setting up an input deck or in running a calculation. There are several pitfalls that the user can encounter, and there are good practices that can avoid many of these pitfalls. Specific examples of current practices for minimizing pitfalls and increasing good practices are discussed. They apply to any thermal-hydraulic system code. These include the following: training and mentoring for the code analyst; user guidelines documentation; internal review and quality assurance of the input deck by knowledgeable individuals; use of standard noding; and fixed noding for each test facility and reactor system. Guidance for the average code analyst is provided in terms of common pitfalls typically encountered and suggestions for good practices in choosing input deck options.