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
Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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.”
William D. Rhodes, Raymond V. Furstenau, Howard A. Larson
Nuclear Technology | Volume 130 | Number 2 | May 2000 | Pages 145-158
Technical Paper | Reactor Safety | doi.org/10.13182/NT00-A3083
Articles are hosted by Taylor and Francis Online.
The generic technique of applying pseudorandom, discrete-level, periodic reactivity perturbation signals to measure the reactivity-to-power frequency response function was extended to the liquid-metal reactor, Experimental Breeder Reactor-II (EBR-II). This technique was developed in the late 1960s and applied in several reactor designs with extensive testing performed at the Molten Salt Reactor Experiment. Signals employed at EBR-II included the pseudorandom binary sequence, quadratic residue binary sequence, pseudorandom ternary sequence, and multifrequency binary sequence. For all the signals employed, the resultant reactor power perturbation was small enough to be acceptable for normal at-power operation and in-place irradiation experiments. The frequency response results are compared with the zero-power frequency response function, yielding a quantitative measure of the EBR-II reactivity feedback effects. The frequency response function results are in good agreement with rod-oscillator data and model predictions. The multifrequency binary sequence concentrated 64% of the total signal power into the four feedback frequencies associated with the predominant feedback time constants. The input signal quality, characterized by the autocorrelation function and power spectra, validated the automatic control rod drive system design and operation as an effective tool for frequency response determination over the range of frequencies where important system dynamic effects occur.