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.
Gwang Seop Son, Dong Hoon Kim, Choul Woong Son, Joon Kyo Kim, Jae Hyun Park
Nuclear Technology | Volume 184 | Number 3 | December 2013 | Pages 297-309
Technical Paper | Reactor Safety | doi.org/10.13182/NT13-A24987
Articles are hosted by Taylor and Francis Online.
This paper presents the architecture of the Safety Programmable Logic Controller (SPLC) for advanced nuclear safety systems and describes the evaluation and analyses of reliability for the SPLC using the Markov model. The SPLC is designed to have structural flexibility for users to select module redundancy according to the requirements of specific applications. To be used for the nuclear safety system, the SPLC is configured for multiple modular redundancy composed of dual modular redundancy and triple modular redundancy. Markov models were developed for three types of existing safety-grade Programmable Logic Controller (PLC) architectures and the SPLC, and the reliabilities of the architectures were then evaluated and analyzed using the models. The results show that the reliability of SPLC is up to 1.6 times better than those of the three PLC architectures, and the mean time to failure (MTTF) of the SPLC is up to 22 000 h better than those of the three. From the reliability analyses, the failure rate of each module in the SPLC should be <2 × 10-4 /h, and the MTTF average increase rate depending on the fault coverage factor (FCF) increment, i.e., MTFF/FCF, is 4 months/0.1.