ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Materials Science & Technology
The objectives of MSTD are: promote the advancement of materials science in Nuclear Science Technology; support the multidisciplines which constitute it; encourage research by providing a forum for the presentation, exchange, and documentation of relevant information; promote the interaction and communication among its members; and recognize and reward its members for significant contributions to the field of materials science in nuclear technology.
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!
Latest Magazine Issues
May 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
June 2024
Nuclear Technology
Fusion Science and Technology
Latest News
Strontium: Supply-and-demand success for the DOE’s Isotope Program
The Department of Energy’s Isotope Program (DOE IP) announced last week that it would end its “active standby” capability for strontium-82 production about two decades after beginning production of the isotope for cardiac diagnostic imaging. The DOE IP is celebrating commercialization of the Sr-82 supply chain as “a success story for both industry and the DOE IP.” Now that the Sr-82 market is commercially viable, the DOE IP and its National Isotope Development Center can “reassign those dedicated radioisotope production capacities to other mission needs”—including Sr-89.
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.