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
Nuclear Installations Safety
Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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
Jul 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
August 2024
Nuclear Technology
Fusion Science and Technology
Latest News
Vogtle-3 shuts down for valve issue
One of the new Vogtle units in Georgia was shut down unexpectedly on Monday last week for a valve issue that has since been investigated and repaired. According to multiple local news outlets, Georgia Power reported on July 17 that Unit 3 was back in service.
Southern Company spokesperson Jacob Hawkins confirmed that Vogtle-3 went off line at 9:25 p.m. local time on July 8 “due to lowering water levels in the steam generators caused by a valve issue on one of the three main feedwater pumps.”
Kwang-Il Ahn, Joon-Eon Yang
Nuclear Technology | Volume 154 | Number 2 | May 2006 | Pages 155-169
Technical Paper | Reactor Safety | doi.org/10.13182/NT06-A3725
Articles are hosted by Taylor and Francis Online.
This paper provides a formal approach for integrating systematically the decoupled levels 1 and 2 probabilistic safety assessment (PSA) models that are developed sequentially and differently in nature into a single PSA model for risk-informed applications (RIAs), with which the change of the level 1 events can be directly reflected in the level 2 model, and thus, the plant is able to evaluate easily the risk associated with important operational issues at the system and component levels. Its fundamental concept is the direct propagation of the level 1 core damage sequence cut sets into the level 2 model so that they are directly linked to the level 2 risk metrics [such as large early release frequency (LERF) and large late release frequency] as well as the level 2 accident sequences. Practical implementation of this approach is achieved through a sequential integration of matrix functions that would be made at successive stages for the level 2 risk calculation. Then, the final result of the integration process is given as a type of Boolean function for the level 1 core damage sequences (or cut sets) solution of each plant damage state (PDS) and PDS solution of the level 2 containment event tree sequences and the release frequencies. The plant-specific application has shown that while the present approach gives a well-formulated single operational model for RIAs, there is no essential difference with results obtained from the conventional level 2 PSA approach that directly uses the numerical results of the level 1 core damage sequences to obtain the level 2 risk metrics.