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The Young Members Group works to encourage and enable all young professional members to be actively involved in the efforts and endeavors of the Society at all levels (Professional Divisions, ANS Governance, Local Sections, etc.) as they transition from the role of a student to the role of a professional. It sponsors non-technical workshops and meetings that provide professional development and networking opportunities for young professionals, collaborates with other Divisions and Groups in developing technical and non-technical content for topical and national meetings, encourages its members to participate in the activities of the Groups and Divisions that are closely related to their professional interests as well as in their local sections, introduces young members to the rules and governance structure of the Society, and nominates young professionals for awards and leadership opportunities available to members.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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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Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
Tarek Zaki, Peter Yarsky
Nuclear Science and Engineering | Volume 184 | Number 3 | November 2016 | Pages 346-352
Technical Paper | doi.org/10.13182/NSE16-14
Articles are hosted by Taylor and Francis Online.
In a related paper (L. Cheng et al., “TRACE/PARCS Analysis of Anticipated Transient Without Scram with Instability for a MELLLA+ BWR/5,” Nucl. Technol. Vol. 196), the results of TRACE/PARCS calculations for representative anticipated transient without scram (ATWS) events leading to core instability (ATWS-I) were presented. In that analysis, instability onset was observed in response to changing plant conditions of power, flow, and feedwater temperature. The baseline calculations were performed without using a PARCS feature to simulate noise in the reactor.
When a simulated reactor is unstable but is in a steady-state condition, an analytical tool may not show the onset of instability because there would not be a perturbation to excite oscillation. Such a condition of artificial stability could not persist in an actual reactor where subtle variation of local conditions (e.g., void fraction) would provide a constant source of perturbation, or “noise.” The regulatory purpose of the current work is to study the reliability of the TRACE/PARCS prediction of instability onset and oscillation growth during ATWS-I by providing a source of noise in the simulation. In addition, the results of this study support a generic methodology recommendation for any future studies.
PARCS has a feature that can simulate the reactivity effect of perturbations in the local void fraction. This feature, referred to as the white noise feature, is used to provide an artificial source of constant, local perturbation that would more closely mimic the actual reactor condition where local void fractions are constantly changing. Sensitivity of the onset timing and growth was studied by varying the magnitude, frequency, and contour of the perturbations applied by the white noise feature.
The study concludes that the onset timing and growth of both the initial corewide and subsequent bimodal oscillation stabilized at a certain combination of perturbation magnitude, frequency range, and frequency resolution. With the appropriate range of these parameters, the instability onset occurs ~20 s earlier, and peak oscillation amplitude is achieved ~15 s earlier when compared to the baseline calculations. Given the importance of oscillation onset and growth on potential fuel damage, this study recommends a specific methodology with respect to white noise to ensure reliable prediction with TRACE/PARCS for future studies.
