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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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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Latest News
Denver Airport may go nuclear
Colorado’s first nuclear power plant of the 21st century could be built at an unconventional site: the Denver International Airport (DEN).
In its mission to gain energy independence and become the greenest airport in the world, DEN has announced that it will conduct a feasibility study to determine the viability of building a small modular reactor on its 33,500-acre campus.
Praneel P. Gulabrao, Kevin T. Clarno
Nuclear Science and Engineering | Volume 195 | Number 2 | February 2021 | Pages 161-172
Technical Paper | doi.org/10.1080/00295639.2020.1794455
Articles are hosted by Taylor and Francis Online.
Photon buildup is a function of energy, medium, and geometry and therefore must be specifically calculated for the case of interest. The Martian atmosphere, mostly comprising carbon dioxide, is becoming more relevant to radiation researchers and therefore warrants the study of this gas mixture’s buildup properties for ionizing photon flux resulting from the secondary effects of galactic cosmic rays and solar flares. Specifically, this work uses the MCNP6 code to develop energy absorption buildup factors in finite slab models for energies ranging from 40 keV to 15 MeV with Martian regolith as the backscattering medium. The Martian carbon dioxide cycle is accounted for by determining maximum and minimum mean densities as a function of orbital position. An isotropic point source model for the atmosphere is also developed using the geometric progression fitting function. Buildup is bounded to a factor of approximately 23 at 100 keV for normally incident photons at the top of the atmosphere. For conservatism, the design problem neglects coherent scattering but assumes bremsstrahlung effects and uses Klein-Nishina free-electron cross sections for Compton scattering.