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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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NN Asks: What did you learn from ANS’s Nuclear 101?
Mike Harkin
When ANS first announced its new Nuclear 101 certificate course, I was excited. This felt like a course tailor-made for me, a transplant into the commercial nuclear world. I enrolled for the inaugural session held in November 2024, knowing it was going to be hard (this is nuclear power, of course)—but I had been working on ramping up my knowledge base for the past year, through both my employer and at a local college.
The course was a fast-and-furious roller-coaster ride through all the key components of the nuclear power industry, in one highly challenging week. In fact, the challenges the students experienced caught even the instructors by surprise. Thankfully, the shared intellectual stretch we students all felt helped us band together to push through to the end.
We were all impressed with the quality of the instructors, who are some of the top experts in the field. We appreciated not only their knowledge base but their support whenever someone struggled to understand a concept.
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%.