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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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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DOE issues new NEPA rule and procedures—and accelerates DOME reactor testing
Meeting a deadline set in President Trump’s May 23 executive order “Reforming Nuclear Reactor Testing at the Department of Energy,” the DOE on June 30 updated information on its National Environmental Policy Act (NEPA) rulemaking and implementation procedures and published on its website an interim final rule that rescinds existing regulations alongside new implementing procedures.
Mei-Ya Wang, Tsung-Kuang Yeh, Hong-Ming Liu, Min Lee
Nuclear Science and Engineering | Volume 174 | Number 2 | June 2013 | Pages 179-187
Technical Paper | doi.org/10.13182/NSE12-16
Articles are hosted by Taylor and Francis Online.
Among the six types of Generation IV reactors, the supercritical water reactor (SCWR) is the only one that adopts light water as the reactor coolant. Different from the boiling, two-phase coolant in the core of a traditional boiling water reactor (BWR), the coolant in an SCWR would remain in one phase throughout the entire primary coolant circuit (PCC) due to its much higher operating temperature (>374°C) and pressure (>22.1 MPa). For a conventional BWR, the coolant is relatively oxidizing due to the presence of hydrogen peroxide and oxygen, directly or indirectly produced via water radiolysis. This outcome eventually leads to degradation of structural materials, primarily stress corrosion cracking. In an SCWR, the solubility of oxygen in the reactor coolant is extremely high. In the absence of the gas stripping effect in a single-phase coolant, worse degradation phenomena are expected to appear in the structural and core components. To ensure proper designs of the structural components and suitable selection of the materials to meet the requirements of operation safety, it would be of great assistance to the design engineers of an SCWR to be aware of the intrinsic state of water chemistry in the entire PCC. Since SCWRs are still at the stage of conceptual design and no practical data are available, a computer model was developed for determining the water chemistry variation and the corrosion behavior of metallic materials in the PCC of a conceptual SCWR. Radiolysis parameters used for calculating the concentrations of major redox species (i.e., [O2], [H2], and [H2O2]) in the reactor coolant were collected from literature reports. However, the lack of sufficient data necessitated that some were derived by extrapolation. Calculations indicated that the concentrations of the two major oxidizing species (H2O2 and O2) could become extremely high at locations inside or near the core, considerably higher than those in typical BWRs. It was therefore speculated that the structural materials in an SCWR may be exposed to an environment not only at a much higher temperature but also one that is more oxidizing than that in a conventional BWR.
