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
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
Meeting Spotlight
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
May 2025
Nuclear Technology
April 2025
Fusion Science and Technology
Latest News
General Kenneth Nichols and the Manhattan Project
Nichols
The Oak Ridger has published the latest in a series of articles about General Kenneth D. Nichols, the Manhattan Project, and the 1954 Atomic Energy Act. The series has been produced by Nichols’ grandniece Barbara Rogers Scollin and Oak Ridge (Tenn.) city historian David Ray Smith. Gen. Nichols (1907–2000) was the district engineer for the Manhattan Engineer District during the Manhattan Project.
As Smith and Scollin explain, Nichols “had supervision of the research and development connected with, and the design, construction, and operation of, all plants required to produce plutonium-239 and uranium-235, including the construction of the towns of Oak Ridge, Tennessee, and Richland, Washington. The responsibility of his position was massive as he oversaw a workforce of both military and civilian personnel of approximately 125,000; his Oak Ridge office became the center of the wartime atomic energy’s activities.”
Antonio F. Dias, Laurance D. Eisenhart, Diane M. Bell, Terry J. Garrett, Glenn J. Neises, Lance J. Agee
Nuclear Technology | Volume 100 | Number 2 | November 1992 | Pages 193-202
Technical Paper | Nuclear Reactor Safety | doi.org/10.13182/NT92-A34742
Articles are hosted by Taylor and Francis Online.
The steamline break accident is one of several specified severe transients addressed in the final safety analysis report for any pressurized water reactor plant as part of the licensing procedure. A rupture in a main steamline in the secondary system causes a sudden cooling of the water in the corresponding primary loop. The cold water flowing into part of the core represents a positive reactivity insertion that must be contained by control rods, which are scrammed into the core almost immediately. Later in the scenario, soluble boron reaches the core from the emergency core cooling system. When simulating a steamline break accident during the licensing procedure, many conservative assumptions are added to the transient description. Historically, a steamline break analysis is performed with a system analysis code like RETRAN, using a rather simplified (point kinetics) description of the core. The three-dimensionality of the event within the core is accounted for by constant “blending factors,” which are used to calculate the evolving point kinetics parameters based on a simplistic cold and hot partition of the core. The ARROTTA-01 and VIPRE-02 computer codes are coupled to allow a detailed three-dimensional simulation of the reactor core during a steamline break event. The results show that a much milder transient is observed than when a point kinetics treatment was used. Test cases study the influence of different core modeling considerations on the overall simulation. The advent of very fast and extremely affordable computing machines (e.g., workstations) should cause the review of some of the simplified approaches initially adopted for many core simulations. More complex and detailed codes can now be routinely employed.