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Division Spotlight
Operations & Power
Members focus on the dissemination of knowledge and information in the area of power reactors with particular application to the production of electric power and process heat. The division sponsors meetings on the coverage of applied nuclear science and engineering as related to power plants, non-power reactors, and other nuclear facilities. It encourages and assists with the dissemination of knowledge pertinent to the safe and efficient operation of nuclear facilities through professional staff development, information exchange, and supporting the generation of viable solutions to current issues.
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!
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Latest News
Digital control system installed at China’s Linglong One
Earlier this month, the first digital control system was put in place at Linglong One, a small modular reactor demonstration project being built at the Changjiang nuclear power plant in Hainan Province. This is the world’s first land-based commercial SMR and is controlled by China National Nuclear Power Co. Ltd., a subsidiary of the China National Nuclear Corporation (CNNC).
Hee-Jin Shim, Chang-Kyun Oh, Hyun-Su Kim, Myung-Hwan Boo, Jong-Jooh Kwon
Nuclear Technology | Volume 190 | Number 1 | April 2015 | Pages 88-96
Technical Paper | Materials for Nuclear Systems | doi.org/10.13182/NT13-150
Articles are hosted by Taylor and Francis Online.
Metal fatigue is a well-known phenomenon whereby material characteristics are deteriorated when even a small load is applied repeatedly. Therefore, an accurate fatigue evaluation is very important in terms of component integrity and reliability. In the design stage, the fatigue evaluation of nuclear class 1 components has to be performed in accordance with Sec. III of the ASME Boiler and Pressure Vessel Code. However, operating experience shows that the design transients are very conservative compared to the actual ones in terms of the heating/cooling rates and the number of transient occurrences. Considering that these two factors affect the thermal stress and thereafter the fatigue usage factor (FUF), the actual fatigue damage can differ from the design fatigue evaluation result. In order to evaluate and monitor the FUF exactly, therefore, various methods have been proposed and widely implemented. Among these, the cycle-based approach (CBA) utilizes the stresses for the design transients and reflects only the actual number of transient occurrences. For this reason, the CBA provides a conservative FUF, although it is very simple and easy to implement. Therefore, a simple and accurate fatigue monitoring method is still needed.
The purpose of this paper is to develop a new approach for effective fatigue damage monitoring. To do this, a thorough review is conducted for the design transients and actual transients for the Westinghouse-type pressurized water reactors in Korea. In addition, a wide range of finite element analyses are carried out varying the heating/cooling rates and the pattern of the transients. Based on this result, a new CBA is proposed incorporating the simple correction factors for both the heating/cooling rates and the transient patterns. A case study is also carried out for the reactor pressure vessel outlet nozzle to verify the validity and applicability of the proposed method. The result indicates that the proposed method can provide a realistic FUF, and more importantly, it is very easy to implement. From these, it is anticipated that the new approach can be widely used in practical fatigue monitoring of nuclear components and piping.