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CCC-0520 DCTDOS.

DCTDOS, Neutron and Gamma Penetration in Composite Duct System

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1. NAME OR DESIGNATION OF PROGRAM:  DCTDOS.
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2. COMPUTERS
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Program name Package id Status Status date
DCTDOS CCC-0520/01 Tested 16-OCT-1990

Machines used:

Package ID Orig. computer Test computer
CCC-0520/01 IBM PC IBM PC
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3. DESCRIPTION OF PROGRAM OR FUNCTION

Estimates are made of neutron and gamma-ray fluence rate (flux density), dose, and spectral features due to penetration through a series of duct segments -
straight sections and bends - in arbitrary combinations; and the resulting composite can include computations for a room at the end,  if there is one. This method was developed for the rapid estimates that are needed for analysis of protection problems against nuclear  weapons, but the concepts are more generally applicable.
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4. METHOD OF SOLUTION

The method, called "orders of reflection", involves the following steps: (1) The penetration of the radiation (neutrons or gamma rays) through single straight ducts of various dimensions is first calculated in a one-velocity treatment, assuming an albedo with an angular dependence given by Chandrasekhar's theory, and assuming isotropic scattering. This penetration probability is calculated for the case of 0, 1, 2, ...n reflections  from walls; (2) An estimate of the energy and angular characteristics of the radiation transmitted after 0, 1, 2, ..., n
reflections is then made by using the results of a Monte Carlo calculation in which the energy and angular characteristics of the multiply-reflected radiation is computed in a space-independent treatment; (3) The results of calculations (1) and (2) are combined  to obtain a transfer function which relates the intensities, direction, and energy characteristics of the radiations entering and leaving a single straight duct or duct segment.
Using the output of one such calculation as the input for the next, the transmissions of the radiation through a sequence of ducts can readily be calculated for any spatial configuration of successive duct legs. The approximations made in the orders-of- reflection method are particularly applicable to neutrons. However,  the method, with some adaptation, has also been found to be applicable to gamma rays.
An extensive data base of neutron and gamma albedo data has been incorporated into the system which allows very rapid calculations of radiation penetration of complex duct configurations. Trial calculations have indicated very good agreement with published Monte Carlo calculations. The method may also be applied to shielding problems pertaining to medical radiation sources and accelerators, but the code has not been tested for these applications.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The neutron calculations use 20 reflections from the duct walls while the gamma-ray calculations use 9 (maximum values of "n" mentioned above).
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6. TYPICAL RUNNING TIME

Execution of the sample problems takes a few  minutes on an IBM PC.
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS:
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9. STATUS
Package ID Status date Status
CCC-0520/01 16-OCT-1990 Tested at NEADB
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10. REFERENCES:
CCC-0520/01, included references:
- L.V. Spencer:
  DCTDOS: Neutron and Gamma Penetration in Composite Duct Systems.
  NSBIR 87-3534, National Bureau of Standards  (February 1987)
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11. MACHINE REQUIREMENTS

The minimum hardware requirements for DCTDOS: an IBM PC or compatible with 2 floppy disk drives and 640K Random Access Memory. An 8087 math coprocessor is desirable.
CCC-0520/01
Main storage requirements on an IBM PC/AT are about 190 kBytes.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
CCC-0520/01 FORTRAN-77
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

The Microsoft Version 3.31 was used to compile the program under PC/DOS 3.1. The Microsoft linker LINK.EXE wa used to create two executable files. One (160K bytes) requires the 8087 coprocessor, and the other (227K  bytes) does not. The executable files are included in the package.
CCC-0520/01
The program ran on the PC/AT under MSDOS version 3.20 with the Microsoft FORTRAN version 5.0 compiler.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHORS

      Contributed by:  Radiation Safety Information Computational Center
                       Oak Ridge National Laboratory
                       Oak Ridge, Tennessee, U. S. A.

      Developed by:    National Bureau of Standards
                       Gaithersburg, Maryland, U. S. A.
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16. MATERIAL AVAILABLE
CCC-0520/01
File name File description Records
CCC0520_01.001 NEA DATA BANK information file 135
CCC0520_01.002 FORTRAN source file 598
CCC0520_01.003 FORTRAN source file 406
CCC0520_01.004 FORTRAN source file 402
CCC0520_01.005 FORTRAN source file 354
CCC0520_01.006 Information file 66
CCC0520_01.007 Executable image 0
CCC0520_01.008 Executable image 0
CCC0520_01.009 Output file for the ARF sample case (NEA) 145
CCC0520_01.010 Output file for PROBLEM1 sample case 53
CCC0520_01.011 Output file for PROBLEM2 sample case 157
CCC0520_01.012 Output file for ORNL sample case 526
CCC0520_01.013 Output file for ARF sample case (original) 145
CCC0520_01.014 Input file for PROBLEM1 11
CCC0520_01.015 Input file for PROBLEM2 11
CCC0520_01.016 Input file for ORNL 48
CCC0520_01.017 Input file for ARF 26
CCC0520_01.018 Input data files 119
CCC0520_01.019 Neutron multireflection albedo data 854
CCC0520_01.020 Gamma-ray multireflection albedo data 853
CCC0520_01.021 Precalculated weights 1430
CCC0520_01.022 DOS file-names 21
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17. CATEGORIES
  • J. Gamma Heating and Shield Design

Keywords: ducts, gamma radiation, neutron flux, shielding.