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
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Mar 2026
Jan 2026
Latest Journal Issues
Nuclear Science and Engineering
April 2026
Nuclear Technology
February 2026
Fusion Science and Technology
Latest News
NRC to add new items to categorical exclusions list
The Nuclear Regulatory Commission has identified five categories of action to add to its list of categorical exclusions to reduce its documentation work under National Environmental Policy Act (NEPA) procedures.
These revisions are included in the final rule, “Categorical exclusions from environmental review,” which was published in the Federal Register on March 30. The final rule will become effective on April 29.
Rodney R. Gay
Nuclear Technology | Volume 36 | Number 2 | December 1977 | Pages 229-237
Technical Note | International Safeguard / Reactor | doi.org/10.13182/NT77-A31930
Articles are hosted by Taylor and Francis Online.
The thermohydraulics of a nuclear reactor during the reflood phase of a hypothetical loss-of-coolant accident can be represented by moving control volume methodology in which six control volumes are used to represent the downcomer, lower plenum, and reactor core. The one-dimensional, homogeneous, equilibrium constitutive equations for two-phase steam/water flow are solved in each control volume and connecting junctions. One of the three core control volumes represents the quench region; it changes size and position based on the axial location of the clad quench temperature and the condensed liquid level in the flow channel. The lengths of the remaining two core control volumes are determined by the position of the quench region. Simulation of actual reflood experiments demonstrates that the methodology predicts reflood-like flow oscillations and reproduces the correct trends in experimental data. The moving control volume methodology has proven itself as a valid concept for reflood hydrodynamics, but further development of the existing EFLOD code is required for simulation of actual reflood experiments.