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.
Explore membership for yourself or for your organization.
Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
August 2025
Fusion Science and Technology
Latest News
The RAIN scale: A good intention that falls short
Radiation protection specialists agree that clear communication of radiation risks remains a vexing challenge that cannot be solved solely by finding new ways to convey technical information.
Earlier this year, an article in Nuclear News described a new radiation risk communication tool, known as the Radiation Index, or, RAIN (“Let it RAIN: A new approach to radiation communication,” NN, Jan. 2025, p. 36). The authors of the article created the RAIN scale to improve radiation risk communication to the general public who are not well-versed in important aspects of radiation exposures, including radiation dose quantities, units, and values; associated health consequences; and the benefits derived from radiation exposures.
Sergio Guarro, David Okrent
Nuclear Technology | Volume 67 | Number 3 | December 1984 | Pages 348-359
Technical Paper | Fission Reactor | doi.org/10.13182/NT84-A33494
Articles are hosted by Taylor and Francis Online.
Logic flowgraph methodology (LFM) is intended to provide a more efficient way of constructing failure models for use in a diagnosis oriented disturbance analysis system. The LFM approach represents a considerable development beyond previous methods and also may be useful in reliability and risk analysis applications. Like the digraph method, LFM produces process models in which the fundamental units of nodes and edges are used to represent process variables and causality relations, respectively. In LFM, however, a more extended set of representation rules allows one to achieve a greater level of modeling capability and flexibility. The LFM models hinge on the interconnection of two distinct networks, namely, the “causality network” and the “condition network.” In a formally defined and organized way the condition network represents the conditions whose occurrence can change or modify the course of process causality flow in the causality network. A test case demonstrates the applicability of LFM to situations of interest in nuclear power plant operation and also shows that once a suitable process flow graph model has been derived, it is possible to obtain any fault-tree structure whose top event can be expressed as a weak or strong perturbation on one of the variables constituting a flowgraph node. This fault-tree construction is performed automatically by a computer routine, accepting as input the logic flowgraph topology and the top event of the desired fault tree. In a disturbance analysis application, this routine also accepts as input a set of field instrumentation signals; using this information on line identifies within a fraction of a second the prime cause of the disturbance by logically developing only those tree branches that the instrumentation indicates as active. In reliability or risk analysis applications, on the contrary, the desired fault tree is developed to its full extent.