NESC0510 VIM2/15.
VIM, 3-D Monte-Carlo Analysis of Fast Critical Assemblies Using Point Cross-Sections
NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROBLEM OR FUNCTION, METHOD OF SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, UNUSUAL FEATURES OF THE PROGRAM, RELATED AND AUXILIARY PROGRAMS, STATUS, REFERENCES, MACHINE REQUIREMENTS, LANGUAGE, OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED, 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 |
|---|---|---|---|
| VIM-2/13 | NESC0510/05 | Tested | 03-FEB-1984 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| NESC0510/05 | IBM 3081 | IBM 3081 |
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3. DESCRIPTION OF PROBLEM OR FUNCTION
VIM solves the three- dimensional steady-state multiplication eigenvalue or fixed source neutron or photon (VIM2/15) transport problem using continuous energy-dependent nuclear data. It was designed for the analysis of fast critical experiments. In VIM2/15, the photon interactions i.e., pair production, coherent and incoherent scattering, and photoelectric events, and photon heating are tallied by group, region, and isotope.
VIM solves the three- dimensional steady-state multiplication eigenvalue or fixed source neutron or photon (VIM2/15) transport problem using continuous energy-dependent nuclear data. It was designed for the analysis of fast critical experiments. In VIM2/15, the photon interactions i.e., pair production, coherent and incoherent scattering, and photoelectric events, and photon heating are tallied by group, region, and isotope.
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4. METHOD OF SOLUTION
VIM uses the Monte Carlo technique to estimate eigenvalues by collision, track length, and analog methods. Geometry options include infinite medium, plate cell lattice, general combinatorial geometry, and repeating lattices of hexagonal or rectangular cells constructed using combinatorial geometry. ENDF/B cross section data are used, including thermal scattering law data. Variance reduction options available include several splitting and Russian roulette techniques, any linear combination of analog and absorption neutron weighting, and combined eigenvalue estimators. An easy-to-use restart option is also available.
In VIM2/15, photon cross sections are defined by composition independent microscopic datasets in the energy range from 1 KeV to 100 MeV. Coherent and incoherent scattering, pair production, and photoelectric cross section data are described by pointwise values with log-log interpolation. Photon heating numbers are specified pointwise with linear-log interpolation. Pair production is simulated by creation of a double-weighted photon of energy 0.511008 MeV, and production by fluorescence is treated explicitly. The Klein-Nishina distribution is sampled exactly for secondary angle and energy during incoherent scattering events.
VIM uses the Monte Carlo technique to estimate eigenvalues by collision, track length, and analog methods. Geometry options include infinite medium, plate cell lattice, general combinatorial geometry, and repeating lattices of hexagonal or rectangular cells constructed using combinatorial geometry. ENDF/B cross section data are used, including thermal scattering law data. Variance reduction options available include several splitting and Russian roulette techniques, any linear combination of analog and absorption neutron weighting, and combined eigenvalue estimators. An easy-to-use restart option is also available.
In VIM2/15, photon cross sections are defined by composition independent microscopic datasets in the energy range from 1 KeV to 100 MeV. Coherent and incoherent scattering, pair production, and photoelectric cross section data are described by pointwise values with log-log interpolation. Photon heating numbers are specified pointwise with linear-log interpolation. Pair production is simulated by creation of a double-weighted photon of energy 0.511008 MeV, and production by fluorescence is treated explicitly. The Klein-Nishina distribution is sampled exactly for secondary angle and energy during incoherent scattering events.
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6. TYPICAL RUNNING TIME
The running time of VIM varies widely with problem characteristics. It depends linearly on the number of isotopes and is also dependent on the number of geometrical zones and the desired statistics. A small problem may run in 10 seconds per batch of 1000 neutron histories on the IBM370/195. NESC executed the VIM2/15 sample problem in approximately 1.2 CPU hours on an IBM4331.
The running time of VIM varies widely with problem characteristics. It depends linearly on the number of isotopes and is also dependent on the number of geometrical zones and the desired statistics. A small problem may run in 10 seconds per batch of 1000 neutron histories on the IBM370/195. NESC executed the VIM2/15 sample problem in approximately 1.2 CPU hours on an IBM4331.
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8. RELATED AND AUXILIARY PROGRAMS
The original WIM system was developed at Atomic International by L.B. Levitt and R.C. Lewis. The package includes a number of auxiliary codes:
The original WIM system was developed at Atomic International by L.B. Levitt and R.C. Lewis. The package includes a number of auxiliary codes:
NESC0510/05
XSEDIT BCD-to-binary or binary-to-BCD cross section editing programFILEONE cross section library preparation code for
variable dimensioning
BANDIT selects the isotopes for a specific set of
problems and splits the cross section data into
energy bands to reduce memory requirements
RETALLY reprocesses VIM history data, collapsing the
edit energy groups and homogenizing regions for
processing selected batches
KEFCODE reedits the eigenvalue estimators for a subset
of batches
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10. REFERENCES
- L.J. Milton:
VIM Users' Guide
ANL Applied Physics Division Memorandum, June 24, 1981.
- VIM2/13. NESC No. 510.7600, VIM2/13 CDC Version Tape Description
and Implementation Information,
NESC Note 85-23, October 31, 1984, Rev August 21, 1986.
- R.N. Blomquist:
VIM Users' Guide
ANL Applied Physics Division Memorandum, November 14, 1986.
- R.E. Prael:
Cross Section Preparation for the Continuous-Energy Monte Carlo
Code VIM
Proc. Conf. on Nuclear Cross Sections and Technology,
March 3-7, 1975, NBS Special Publication 425, pp. 447-450.
- R.E. Prael and H. Henryson II:
A Comparison of VIM and MC**2-2 - Two Detailed Solutions of the
Neutron Slowing-Down Problem
Proc. Conf. on Nuclear Cross Sections and Technology
March 3-7, 1975, NBS Special Publication 425, pp. 451-454.
- L.B. Levitt, R.C. Lewis:
VIM1, A Non-multigroup Monte Carlo Code for Analysis of Fast
Critical Assemblies
AI-AEC-12951, May 15, 1970.
- VIM2/15, NESC No. R510.3033B, VIM2/15 Edition B Tape Description,
and Implementation Information
NESC Note 90-130, September 28, 1990.
- L.J. Milton:
VIM Users' Guide
ANL Applied Physics Division Memorandum, June 24, 1981.
- VIM2/13. NESC No. 510.7600, VIM2/13 CDC Version Tape Description
and Implementation Information,
NESC Note 85-23, October 31, 1984, Rev August 21, 1986.
- R.N. Blomquist:
VIM Users' Guide
ANL Applied Physics Division Memorandum, November 14, 1986.
- R.E. Prael:
Cross Section Preparation for the Continuous-Energy Monte Carlo
Code VIM
Proc. Conf. on Nuclear Cross Sections and Technology,
March 3-7, 1975, NBS Special Publication 425, pp. 447-450.
- R.E. Prael and H. Henryson II:
A Comparison of VIM and MC**2-2 - Two Detailed Solutions of the
Neutron Slowing-Down Problem
Proc. Conf. on Nuclear Cross Sections and Technology
March 3-7, 1975, NBS Special Publication 425, pp. 451-454.
- L.B. Levitt, R.C. Lewis:
VIM1, A Non-multigroup Monte Carlo Code for Analysis of Fast
Critical Assemblies
AI-AEC-12951, May 15, 1970.
- VIM2/15, NESC No. R510.3033B, VIM2/15 Edition B Tape Description,
and Implementation Information
NESC Note 90-130, September 28, 1990.
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NESC0510/05
| File name | File description | Records |
|---|---|---|
| NESC0510_05.003 | VIM-2/13 INFORMATION FILE | 81 |
| NESC0510_05.004 | VIM-2/13 JCL | 1418 |
| NESC0510_05.005 | VIM-2/13 SOURCE PROGRAM (FTN-4 & ASSEMBLER) | 24605 |
| NESC0510_05.006 | VIM LINKEDT INPUT (JOB4A) | 38 |
| NESC0510_05.007 | BANDIT LINKEDT INPUT (JOB9) | 9 |
| NESC0510_05.008 | RETALLY LINKEDIT INPUT (JOB12) | 18 |
| NESC0510_05.009 | FILEONE INPUT (JOB8) | 110 |
| NESC0510_05.010 | XSEDIT INPUT FOR BCD-BIN CONVERSION | 10 |
| NESC0510_05.011 | BANDIT INPUT FOR TEST CASE (JOB10) | 2 |
| NESC0510_05.012 | VIM INPUT FOR TEST CASE (JOB11) | 51 |
| NESC0510_05.013 | FILEONE OUTPUT OF TEST CASE (JOB8) | 457 |
| NESC0510_05.014 | BANDIT OUTPUT OF TEST CASE (JOB10) | 1354 |
| NESC0510_05.015 | VIM OUTPUT OF TEST CASE (JOB11) | 8939 |
| NESC0510_05.016 | RETALLY OUTPUT OF TEST CASE (JOB13) | 652 |
| NESC0510_05.017 | KEFCODE OUTPUT OF TEST CASE (JOB15) | 119 |
| NESC0510_05.018 | USER'S GUIDE | 9941 |
| NESC0510_05.019 | ENDF/B-4 X-SEC FOR 100 MATERIALS | 274645 |
Keywords: ENDF/B, Monte Carlo method, ZPPR reactors, ZPR-3 reactors, cell calculation, criticality, hexagonal lattices, neutron transport theory, photon transport, reactor lattices, shielding, slowing-down, zebra reactors.