Computer Programs
NEA-0391 DLS.
last modified: 01-JUL-1975 | catalog | categories | new | search |

# NEA-0391 DLS.

#### DLS, 2-D Diffusion with Line-of-Sight Method for Cavities

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1. NAME OR DESIGNATION OF PROGRAM:  DLS.
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2. COMPUTERS
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Program name Package id Status Status date
DLS NEA-0391/01 Tested 01-JUL-1975

Machines used:

Package ID Orig. computer Test computer
NEA-0391/01 CDC 6600 CDC 6600
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3. NATURE OF PHYSICAL PROBLEM SOLVED

DLS is a two-dimensional diffusion program supplemented by the line-of-sight technique for the treatment of cavities.
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4. METHOD OF SOLUTION

Within material-filled regions, diffusion theory is used, while cavities are treated using the line-of-sight method.  The numerical solution of the diffusion equation is based upon balance formulae for all volume elements containing terms for source, absorption, and leakage. At the boundary of a cavity, the term for the entering currents used in the balance equation include  the contributions of all other elements at the boundary of the cavity which can be seen from the element considered. These contributions are calculated with the aid of leakage factors and view factors. The leakage factors describe the ratio between the leaving current and the flux density. The program contains various options to calculate these leakage factors. The view factors describe the probability that a neutron leaving the cavity surface of an arbitrary volume element hits the considered volume element directly. The calculation of the factors proceeds upon the assumption that the neutrons emitted into the cavity will have a cosine shaped directional distribution.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The program is written for r-z geometry.
Only cavities with strictly rectangular cross sections can be considered. For example, L-shaped cavities cannot be treated.
Maximum number of - energy groups - 26
view factors - 20000
cavities - 5
materials - 15
The sum of radial and axial mesh intervals may not exceed 170.
The total mesh number is restricted by machine size.
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6. TYPICAL RUNNING TIME

10 to 40 minutes for practical reactor shields (26 groups).
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7. UNUSUAL FEATURES OF THE PROGRAM:  Treatment of cavities.
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8. RELATED OR AUXILIARY PROGRAMS: RELATED AND AUXILIARY PROGRAMS
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9. STATUS
Package ID Status date Status
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10. REFERENCES

- H. Vossebrecker:
Two-Dimensional Shielding Calculations Using a Combination of Diffusion Theory and Line-Of-Sight Method
Atomkernenergie vol.19 (1972) LFG. 1 pp. 14-16.
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11. MACHINE REQUIREMENTS

CDC 6400 - minimum 48k words core storage. One tape unit. Disk with random access.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NEA-0391/01 FORTRAN-IV
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13. OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED:  SCOPE 3.3.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

ANY OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS
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15. NAME AND ESTABLISHMENT OF AUTHOR

H. Vossebrecker and G. Groenefeld
INTERATOM
506 Bensberg, Germany
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16. MATERIAL AVAILABLE
NEA-0391/01
File name File description Records
NEA0391_01.001 SOURCE PROGRAM (F4) 10071
NEA0391_01.002 SAMPLE PROBLEM DATA 278
NEA0391_01.003 SAMPLE PROBLEM PRINTED OUTPUT 6077
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17. CATEGORIES
• C. Static Design Studies
• J. Gamma Heating and Shield Design

Keywords: absorption, cavities, diffusion equations, leaks, shielding, two-dimensional.