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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 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.
Yun Long, Yi Yuan, Mujid S. Kazimi, Ronald G. Ballinger, Edward E. Pilat
Nuclear Technology | Volume 138 | Number 3 | June 2002 | Pages 260-272
Technical Paper | Fuel Cycle and Management | doi.org/10.13182/NT02-A3293
Articles are hosted by Taylor and Francis Online.
Fission gas release in thoria-urania fuel has been investigated by creating a specially modified FRAPCON-3 code. Because of the reduced buildup of 239Pu and a flatter distribution of 233U, the new model THUPS (Thoria-Urania Power Shape) was developed to calculate the radial power distribution, including the effects of both plutonium and 233U. Additionally, a new porosity model for the rim region was introduced at high burnup. The mechanisms of fission gas release in ThO2-UO2 fuel are expected to be essentially similar to those of UO2 fuel; therefore, the general formulations of the existing fission gas release models in FRAPCON-3 were retained. However, the gas diffusion coefficient was adjusted to a lower level to account for the smaller observed release fraction in the thoria-based fuel. To model the accelerated fission gas release at high burnup properly, a new athermal fission gas release model was introduced. The modified version of FRAPCON-3 was calibrated using the measured fission gas release data from the light water breeder reactor. Using the new model to calculate the gas release in typical pressurized water reactor hot pins gives data that indicate that the ThO2-UO2 fuel will have considerably lower fission gas release above a burnup of 50 MWd/kg HM.
