Monte Carlo Simulation of Atmospheric Neutron Transport at High Altitudes Using MCNP

Abstract

Neutron transport calculations were performed using the Monte Carol code, MCNP. The transport problem considered has a point source at high altitude (40 km). Since atmospheric density decreases with altitude, two-dimensional effects (cylindrical coordinates) can be important. Results were compared to those obtained with the SMAUG-II computer code, which performs mass-integral scaling of approximate fits to one-dimensional spherical discrete ordinates solutions. These comparisons show the importance of two-dimensional computations. The report discusses practical issues of applying MCNP to this problem, without code modifications and includes example input files for MCNP and for SMAUG-II. Computational modelling of neutron transport in the atmosphere is complicated by the variation of air density with altitude.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1990
Accession Number
ADA226773

Entities

People

  • David L. Monti
  • David Wesley
  • Donald R. Culp
  • James R. Shoemaker
  • Kirk A. Mathews

Organizations

  • Air Force Institute of Technology

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Air Force
  • Atmospheric Density
  • Boltzmann Equation
  • Computational Science
  • Computer Programs
  • Computers
  • Coordinate Systems
  • Elevation
  • Equations
  • Geometry
  • High Altitude
  • Mean Free Path
  • Monte Carlo Method
  • Neutron Cross Sections
  • Operating Systems
  • Plastic Explosives
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Calculus or Mathematical Analysis
  • Computational Fluid Dynamics (CFD)
  • Nuclear and Radiation Engineering.