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Atlanta, GA|Atlanta Marriott Marquis
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Wright officially sworn in for third term at the NRC
The Nuclear Regulatory Commission recently announced that David Wright, after being nominated by President Trump and confirmed by the Senate, was ceremonially sworn in as NRC chair on September 8.
This swearing in comes more than a month after Wright began his third term on the commission; he began leading as chair July 31. His term will conclude on June 30, 2030.
John T. Mihalczo
Nuclear Technology | Volume 175 | Number 2 | August 2011 | Pages 498-508
Technical Paper | Radiation Measurements and General Instrumentation | doi.org/10.13182/NT11-A12320
Articles are hosted by Taylor and Francis Online.
Prompt neutron decay at delayed criticality was measured by Oak Ridge National Laboratory for uranium-reflected highly enriched uranium (HEU) and Pu metal spheres (FLATTOP), for an unreflected Pu metal (4.5% 240Pu) sphere (JEZEBEL) at Los Alamos National Laboratory (LANL) and for an unreflected HEU metal sphere at Oak Ridge Critical Experiments Facility. The average prompt neutron decay constants from hundreds of Rossi- and randomly pulsed neutron measurements with 252Cf at delayed criticality are as follows: 3.8458 ± 0.0016 × 105 s-1 , 2.2139 ± 0.0022 × 105 s-1 , 6.3126 ± 0.0100 × 105 s-1 , and 1.1061 ± 0.0009 × 106 s-1 , respectively. These values agree with previous measurements by LANL for FLATTOP, JEZEBEL, and GODIVA I as follows: 3.82 ± 0.02 × 105 s-1 for a uranium core; 2.14 ± 0.05 × 105 s-1 and 2.29 × 105 s-1 (uncertainty not reported) for a plutonium core; 6.4 ± 0.1 × 105 s-1 , and 1.1 ± 0.1 × 106 s-1 , respectively, but have smaller uncertainties because of the larger number of measurements. For the FLATTOP and JEZEBEL assemblies, the measurements agree with calculations. Traditionally, the calculated decay constants for the bare uranium metal sphere GODIVA I and the Oak Ridge Uranium Metal Sphere were higher than experimental by [approximately]10%. Other energy-dependent quantities for the bare uranium sphere agree within 1%.