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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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The Frisch-Peierls memorandum: A seminal document of nuclear history
The Manhattan Project is usually considered to have been initiated with Albert Einstein’s letter to President Franklin Roosevelt in October 1939. However, a lesser-known document that was just as impactful on wartime nuclear history was the so-called Frisch-Peierls memorandum. Prepared by two refugee physicists at the University of Birmingham in Britain in early 1940, this manuscript was the first technical description of nuclear weapons and their military, strategic, and ethical implications to reach high-level government officials on either side of the Atlantic. The memorandum triggered the initiation of the British wartime nuclear program, which later merged with the Manhattan Engineer District.
Tsuyoshi Misawa, Seiji Shiroya, Keiji Kanda
Nuclear Technology | Volume 116 | Number 1 | October 1996 | Pages 9-18
Technical Paper | Fission Reactor | doi.org/10.13182/NT96-A35308
Articles are hosted by Taylor and Francis Online.
Experiments on the reactivity worth of beryllium metal were performed using the Kyoto University Critical Assembly, and they were analyzed to examine the validity of the computational method to treat (n,2n) reactions in calculations. The experimental results demonstrated that beryllium metal has positive reactivity worth compared with graphite. In the analysis, (n,2n) reactions were treated as modifying scattering cross sections in a transport calculation, whereas both scattering and absorption cross sections should be modified in a diffusion calculation. The results of calculations for the reactivity worth of beryllium agreed with experimental data within a few percent in the calculated-to-experimental ratio. Calculated results indicated that (n,2n) reactions of beryllium contribute by ∼85% to the positive reactivity worth compared with graphite in these experiments at a thermal reactor. Moreover, through the improved neutron and gamma-ray coupled calculation, the effect of (γ,n) reactions of beryllium on reactivity was estimated. It was found that (γ,n) reactions of beryllium can be negligible so far as this reactivity worth is concerned.