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Division Spotlight
Operations & Power
Members focus on the dissemination of knowledge and information in the area of power reactors with particular application to the production of electric power and process heat. The division sponsors meetings on the coverage of applied nuclear science and engineering as related to power plants, non-power reactors, and other nuclear facilities. It encourages and assists with the dissemination of knowledge pertinent to the safe and efficient operation of nuclear facilities through professional staff development, information exchange, and supporting the generation of viable solutions to current issues.
Meeting Spotlight
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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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Latest News
WIPP improves utility shaft safety, begins infrastructure project
Harrison Western Shaft Sinkers (HWSS), the company drilling a new utility shaft at the Department of Energy’s Waste Isolation Pilot Plant in New Mexico, has retained a safety culture expert following a near-miss accident in the shaft late last year. The safety expert will conduct monthly facilitated discussions with crews working on the shaft to reinforce expectations for identifying concerns regarding unsafe circumstances, according to a recent report by the Defense Nuclear Facilities Safety Board (DNFSB).
Jan Peter Hessling
Nuclear Science and Engineering | Volume 184 | Number 3 | November 2016 | Pages 388-399
Technical Paper | doi.org/10.13182/NSE16-8
Articles are hosted by Taylor and Francis Online.
For evaluation of the uncertainty of nuclear power calculations, the Wilks approach has the appearance of an ideal tool. A conservatively estimated bound is obtained as the r’th most extreme model result, of a random sample of size determined by r. The methodology is noninvasive and simple and seems efficient and adequate. However, as this paper shows, these attributes come with a high price of large bias and substantial sampling variance. This jeopardizes its utilization as well as lowers its credibility and perceived efficiency. The unfortunate combination of random sampling and faithful estimation may result in a relative sampling uncertainty of the estimated bound(s) of no less than 100%. What is defined as credibility, i.e., the probability that the estimated bound is conservative relative to the true result, is well below the confidence relating the targeted bound(s) to the true result, which for the default application of the Wilks method translates into an expected failure rate of up to 10% (instead of 5%) of estimated bounds. To compensate for this deficit in credibility compared to the chosen level of confidence, adjustments of current practice are proposed. The application to modeling uncertainty is to be clearly distinguished from the original experimental sampling problem addressed by Wilks. Here, more is known but not utilized. A viable novel alternative based on so-called deterministic sampling with higher accuracy, precision, and efficiency will therefore be briefly discussed and illustrated.