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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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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.
Ji Bok Lee, Byong Whie Lee, Byung Chul Lee
Nuclear Science and Engineering | Volume 121 | Number 2 | October 1995 | Pages 334-344
Technical Paper | doi.org/10.13182/NSE95-A28569
Articles are hosted by Taylor and Francis Online.
A radiation streaming analysis for the radial and tangential beam tubes of a 250-kW TRIGA reactor was performed using the MCNP-MCNP coupling method. The measurements of the neutron flux and dose rate in the beam tubes were also conducted using gold-aluminum foils and thermoluminescent dosimeters. When compared with the experimental results, the calculated thermal neutron flux reproduces the measurement well, i.e., within 2 to 90%. The calculated nonthermal neutron and gamma-ray dose rates show about the same distribution along the beam tube as the measurements. For the neutron dose rate, there is a big discrepancy between the calculation and the measurement for the radial beam tube but good agreement for the tangential tube. The calculational method using MCNP-MCNP coupling, which is used here, may well be applicable to analyzing the particle streaming phenomena in the beam tube of a research reactor. The beam characteristics of the radial and tangential tubes were investigated based on MCNP calculations. The thermal neutron fluxes are about the same in both beam tubes, but the ratios of the thermal-to-nonthermal neutron flux and the thermal neutron-to-gamma-ray flux in the tangential beam tube increase from only 12% and 18% higher at the nose to 2.4 times and 2.8 times higher at 130 cm from the nose, respectively, compared with those for the radial tube. Thus, the tangential beam tube gives a better neutron beam quality, i.e., the same thermal neutron flux and lower nonthermal neutron and gamma-ray fluxes at the tangential beam tube exit as compared with the radial one.
