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Metz on Harold Denton: Memories of a life in nuclear safety
A number of years ago, historian and writer Chuck Metz Jr. was at the Bush’s Visitor Center in Tennessee’s Great Smoky Mountains when he ran into former Nuclear Regulatory Commission official Harold Denton and his wife. Metz was at the visitor center, which opened in 2010 and is now a tourist hotspot, because, as he explained to the Dentons at the time, he had overseen the development of its on-site museum and had written a companion coffee-table history book.
The chance meeting turned into a friendship and a fruitful collaboration. Denton, who in 1979 was the public spokesperson for the NRC as the Three Mile Island-2 accident unfolded, had been working on his memoir, but he was stuck. He asked Metz for help with the organization and compilation of his notes. “I was about to retire,” Metz said, “but I thought that exploring the nuclear world might be an interesting change of pace.”
Denton passed away in 2017, but by then Metz had spent many hours with his fast friend and was able to complete the memoir, Three Mile Island and Beyond: Memories of a Life in Nuclear Safety, which was published recently by ANS. Metz shared some of his thoughts about Denton and the book with Nuclear News. The interview was conducted by NN’s David Strutz.
Aaron E. Craft, Jeffrey C. King
Nuclear Technology | Volume 172 | Number 3 | December 2010 | Pages 255-272
Technical Paper | Photon and Neutron Transport and Shielding | dx.doi.org/10.13182/NT10-A10934
Articles are hosted by Taylor and Francis Online.
A survey of neutron-attenuating materials is conducted, followed by a systematic optimization of the radiation shield configuration for the Affordable Fission Surface Power System. Water, borated water, boron carbide, boron-doped beryllium, zirconium hydride, and lithium hydride are evaluated for neutron shielding, and tungsten is considered for gamma shielding. Lithium hydride, borated water, and boron carbide are selected for further consideration, and radial, upper axial, and lower axial shield sections are developed separately from these materials and then combined to form complete shields. Two competing effects determine the optimal position of the tungsten layer: increasing secondary gamma production due to fast neutron scattering when the tungsten layer is placed closer to the core, and radially increasing mass when placed farther from the core. The optimal position of the tungsten layer is found for each shield configuration and material. The as-landed configuration of each radiation shield allows a maximum dose of 5 rem/yr to an outpost 1 km from the reactor core. The shield also protects the SmCo magnets in the alternators of the Stirling power converters, allowing a maximum dose of 2 Mrad gamma and 1014 n/cm2 fast neutron fluence to the magnets over the 8-yr design lifetime. A minimum mass is found for each shield section while meeting these dose limits. The radial shield section is cylindrical, and the upper and lower axial shield sections are conical in shape. Axial shields with a range of pitch and thickness are analyzed, and the optimal shapes of the upper and lower axial shields for each material are found. The three sections of the shield are combined to form a complete shield. The lithium hydride shield is the lightest of the final shields at 6215 kg. The borated water shield is the second lightest at 6663 kg, which is 448 kg more than the lithium hydride shield. The boron carbide shield is the most massive at 8315 kg, which is 2100 kg more than the lithium hydride shield.