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
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
Meeting Spotlight
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
May 2025
Nuclear Technology
April 2025
Fusion Science and Technology
Latest News
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.
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.