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
Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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.
Yue Guan, Fei Li, Mohammad Modarres
Nuclear Technology | Volume 133 | Number 3 | March 2001 | Pages 290-309
Technical Paper | Reactor Safety | doi.org/10.13182/NT01-A3175
Articles are hosted by Taylor and Francis Online.
A method of integrating traditional thermal-hydraulic (TH) analysis with probabilistic assessment (PA) (called the TH-PA method) has been developed. This method allows for an exhaustive search through a set of individually developed but subsequently linked logic models to screen and identify accident scenarios. The logic models consist of a probabilistic risk assessment (PRA) used for probabilistic screening purpose and an ensemble of integrated behavior logic diagrams (IBLDs). The PRA model represents the functional/logical relationships of the components and accident scenarios, the same way as is modeled in the conventional PRAs. The IBLDs hierarchically represent system interactions/dependencies due to TH phenomena and human actions. This hierarchy also shows causal factors and consequences of plant states, and identifies induced system failures. The TH-PA method relies on two types of scenario screening: probabilistic screening (PA screening) and TH screening. The PA screening eliminates scenarios with low frequencies (e.g., <10-10/reactor-yr). The traditional frequency-based screening method used in the PRAs has been adopted for PA screening. The TH screening eliminates scenarios that do not expect to result in core uncovery. For the TH screening, a simple accident trajectory approach has been devised. A trajectory represents the collapsed liquid volume fraction in the reactor primary system as a function of primary pressure. The trajectories are based on simple mass and energy conservation equations (if the TH-PA method is applied to a system where mechanical energy transfer is important, momentum conservation should also be considered). The roles of each plant system are then identified by indicating whether the system is a "source" or a "sink" for mass and energy at a given time during accident progression. Based on an input set that represents the plant system failures and the stage of the transient, the accident trajectory is developed. The accident trajectory allows for the evaluation of safety significance of scenarios. The trajectory also determines whether the core becomes uncovered, should the input conditions (i.e., conditions described by the input set) remain unchanged.