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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Shifting the paradigm of supply chain
Chad Wolf
When I began my nuclear career, I was coached up in the nuclear energy culture of the day to “run silent, run deep,” a mindset rooted in the U.S. Navy’s submarine philosophy. That was the norm—until Fukushima.
The nuclear renaissance that many had envisioned hit a wall. The focus shifted from expansion to survival. Many utility communications efforts pivoted from silence to broadcast, showcasing nuclear energy’s elegance and reliability. Nevertheless, despite being clean baseload 24/7 power that delivered a 90 percent capacity factor or higher, nuclear energy was painted as risky and expensive (alongside energy policies and incentives that favored renewables).
Economics became a driving force threatening to shutter nuclear power. The Delivering the Nuclear Promise initiative launched in 2015 challenged the industry to sustain high performance yet cut costs by up to 30 percent.
J. J. Rush, D. W. Connor, and R. S. Carter
Nuclear Science and Engineering | Volume 25 | Number 4 | August 1966 | Pages 383-389
Technical Paper | doi.org/10.13182/NSE66-A18558
Articles are hosted by Taylor and Francis Online.
The leakage flux from an 18 × 18 in. cylinder of D2O with a beam of pile neutrons incident at its center has been studied at D2O temperatures from 22° to 293°K. Intensities through beryllium and graphite filters, as well as indium foil transmissions, have been measured to determine cold-neutron fractions and neutron temperatures for the emerging spectra. The results of these measurements show that large volumes of D2O ice can be useful as low-temperature moderators in reactors. The percentage of leakage neutrons with λn ≥ 3.95 Å is 21% at 22°K, a 20-fold increase over the fraction at 293°K, and about twice the value at 100°K. The neutron temperature of the leakage spectrum, calculated from the transmission data assuming a Maxwellian distribution, decreases with moderator temperature, reaching a value of about 75° for D2O at 22°K. An abrupt increase in the fraction of cold neutrons is observed at the D2O freezing point, which appears to reflect a change in the transport rather than the moderating properties of the D2O, due to a decrease in the cross section for long-wavelength neutrons.
