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
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
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
Jun 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
August 2024
Nuclear Technology
July 2024
Fusion Science and Technology
Latest News
NRC engineers share their expertise at the University of Puerto Rico
Robert Roche-Rivera and Marcos Rolón-Acevedo are licensed professional engineers who work at the U.S. Nuclear Regulatory Commission. They are also alumni of the University of Puerto Rico–Mayagüez (UPRM) and have been sharing their knowledge and experience with students at their alma mater since last year, serving as adjunct professors in the university’s Department of Mechanical Engineering. During the 2023–2024 school year, they each taught two courses: Fundamentals of Nuclear Science and Engineering, and Nuclear Power Plant Engineering.
Tai-Hung Wu, De-Cheng Chen
Nuclear Technology | Volume 205 | Number 6 | June 2019 | Pages 867-880
Technical Note | doi.org/10.1080/00295450.2018.1533320
Articles are hosted by Taylor and Francis Online.
Station blackout (SBO) sequences for a Westinghouse-designed three-loop pressurized water reactor (PWR) with large dry containment are investigated. Recovery of alternating-current power is considered under two separate headings in event trees of loss of off-site power: recovery of the off-site power and recovery of the emergency diesel generators (EDGs) or diesel generator 5. A reactor coolant pump seal leakage model under SBO conditions for a Westinghouse PWR with high-temperature O-rings is used. Seal failure mechanisms, including popping open, binding, and O-ring extrusion, are considered. Success criteria are established based on the results of thermal-hydraulic calculations via the MELCOR and/or RELAP-5 codes. Furthermore, the WinNUPRA software package is used for sequence quantification.
Three primary models are addressed: Basic, WOG2000, and Ultimate Response Guideline (URG). The core damage frequency (CDF) of SBO sequences for the Basic model is found to be very optimistic and underestimated. The improvement on CDF by introducing the URG model is found to be dependent primarily on the reliability of plant operators in performing the procedure URG under SBO situations.
Two sensitivity analyses on the passive shutdown seal (PSDS) are performed: WOG2000 (PSDS) and URG (PSDS). The low-failure-probability PSDS results in a >94% improvement in CDF due to SBO since the CDF contribution from long-term SBO sequences becomes negligible. Furthermore, the URG strategies are shown to have a significant impact on the reduction of CDF since seal leakage is no longer a concern in the presence of the PSDS.
The way that power recovered is distinguished from off-site power or on-site EDGs and the way that SBO CDF is assessed make the present study more realistic than general SBO models.
A key analysis of the confidence bands of the SBO CDF with the aid of the uncertainty measure is also performed to observe the induced effects by the probabilistic seal failure modes and PSDS.