NEA-0384 TRIGON.
TRIGON, 2-D Homogeneous and Inhomogeneous Fixed Source Neutron Diffusion for Triangular or Hexagonal Mesh
NAME OR DESIGNATION OF PROGRAM, COMPUTER, NATURE OF PHYSICAL PROBLEM SOLVED, METHOD OF SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, FEATURES, RELATED AND AUXILIARY PROGRAMS, STATUS, REFERENCES, MACHINE REQUIREMENTS, LANGUAGE, OPERATING SYSTEM OR MONITOR UNDER WHICH PROGRAM IS EXECUTED, ANY OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHOR, MATERIAL, CATEGORIES
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| Program name | Package id | Status | Status date |
|---|---|---|---|
| TRIGON | NEA-0384/01 | Tested | 01-NOV-1979 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| NEA-0384/01 | UNIVAC 1110 | UNIVAC 1110 |
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3. NATURE OF PHYSICAL PROBLEM SOLVED
The program solves the multigroup time-independent neutron diffusion equations with arbitrary group to group scattering in two space dimensions. In addition to homogeneous or K-effective calculations also inhomogeneous or fixed source calculations can be made. The problem may be specified with both external and internal logarithmic derivative boundary conditions.
Using pointwise flux distribution the program calculates automatically the average flux and power distributions over equal hexagons of arbitrary size into which the area of solution is divided by the user.
The program solves the multigroup time-independent neutron diffusion equations with arbitrary group to group scattering in two space dimensions. In addition to homogeneous or K-effective calculations also inhomogeneous or fixed source calculations can be made. The problem may be specified with both external and internal logarithmic derivative boundary conditions.
Using pointwise flux distribution the program calculates automatically the average flux and power distributions over equal hexagons of arbitrary size into which the area of solution is divided by the user.
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4. METHOD OF SOLUTION
The diffusion theory equations are approximated by 7-point difference equations for the uniform triangular or hexagonal mesh grid. In the former case, the mesh points are situated at the cross sections of the mesh lines separating different materials and in the latter case at the centre points of the homogeneous mesh hexagons. The difference equations are solved iteratively by the line over-relaxation technique utilizing an exponential over-relaxation procedure. Coarse mesh rebalancing and special asymptotic flux extrapolations are used to improve the convergence.
The diffusion theory equations are approximated by 7-point difference equations for the uniform triangular or hexagonal mesh grid. In the former case, the mesh points are situated at the cross sections of the mesh lines separating different materials and in the latter case at the centre points of the homogeneous mesh hexagons. The difference equations are solved iteratively by the line over-relaxation technique utilizing an exponential over-relaxation procedure. Coarse mesh rebalancing and special asymptotic flux extrapolations are used to improve the convergence.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM
Because a variable dimensioning technique is employed, the only restriction on problem size is the available core storage. The option of using auxiliary storage (drum, disk or tape) during iteration allows to run large problems even with rather small core storage.
Because a variable dimensioning technique is employed, the only restriction on problem size is the available core storage. The option of using auxiliary storage (drum, disk or tape) during iteration allows to run large problems even with rather small core storage.
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6. TYPICAL RUNNING TIME
For entirely core contained problems, the running time is about 0.2 msec per space-energy point per iteration. Since the program is designed for use in multiprocessing environment there is no simultaneous performance of computation and data transfer. Thus the running time will be increased in batch processing if auxiliary storage is used during iteration.
For entirely core contained problems, the running time is about 0.2 msec per space-energy point per iteration. Since the program is designed for use in multiprocessing environment there is no simultaneous performance of computation and data transfer. Thus the running time will be increased in batch processing if auxiliary storage is used during iteration.
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NEA-0384/01, included references:
- E. Kaloinen:TRIGON, A Two-Dimensional Multigroup Diffusion Code for Trigonal
or Hexagonal Mesh
Nuclear Engineering Laboratory, Report 1 (May 1973)
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NEA-0384/01
| File name | File description | Records |
|---|---|---|
| NEA0384_01.001 | SOURCE (F4 AND ASSEMBLER) | 2840 |
| NEA0384_01.002 | SAMPLE PROBLEM INPUT | 57 |
| NEA0384_01.003 | SAMPLE PROBLEM OUTPUT | 240 |
| NEA0384_01.004 | JCL AND INFORMATION | 82 |
Keywords: difference equations, flux distribution, hexagonal configuration, iterative methods, multigroup, neutron diffusion equation, neutron flux, power distribution, two-dimensional.