Computer Programs

NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROGRAM 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 AUTHORS, MATERIAL, CATEGORIES

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Program name | Package id | Status | Status date |
---|---|---|---|

DOT-4.2 | CCC-0320/04 | Tested | 20-JUL-1984 |

Machines used:

Package ID | Orig. computer | Test computer |
---|---|---|

CCC-0320/04 | IBM 3033 | IBM 3081 |

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3. DESCRIPTION OF PROGRAM OR FUNCTION

DOT-4 determines the flux or fluence of particles throughout a two-dimensional geometric system due to sources either generated as a result of particle interaction with the medium, or incident upon the system from independent sources. The principal application is to the deep penetration transport of neutrons and photons. Criticality (k-type and search) problems can be solved. Numerous printed edits of the results are available, and results can be transferred to output files for subsequent analysis.

DOT-4 determines the flux or fluence of particles throughout a two-dimensional geometric system due to sources either generated as a result of particle interaction with the medium, or incident upon the system from independent sources. The principal application is to the deep penetration transport of neutrons and photons. Criticality (k-type and search) problems can be solved. Numerous printed edits of the results are available, and results can be transferred to output files for subsequent analysis.

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4. METHOD OF SOLUTION

The Boltzmann transport equation is solved using the method of discrete ordinates, diffusion theory, or a special "combined P1" solution. In the discrete ordinates method, the primary mode of operation, balance equations are solved for the flow of particles moving in a set of discrete directions in each cell of a space mesh, and in each group of a multigroup energy mesh. Iterations are performed until all implicitness in the coupling of cells, directions, groups, and source regeneration has been resolved. Methods are available to accelerate convergence by space- dependent rebalance and by successive over-relaxation. Anisotropic cross sections can be expressed in a Legendre expansion of arbitrary order. Output data sets can be used to provide an accurate restart of a previous problem.

Special techniques are available to remove the effects of negative fluxes caused by the finite space and direction meshes, and of negative scattering due to truncation of the cross-section expansion. The space mesh can be described such that the number of first-dimension (I) intervals varies with the second dimension (J). The number of discrete directions can vary across the space mesh and with energy. The order of Legendre expansion can vary with cross- section set and with energy group.

Provision is made to treat sources resulting from the first collision of particles from a point source. In this case, flux due to uncollided particles is included in the output edits.

Direction sets can be biased, with more discrete direction segments per unit solid angle in some directions than in others.

The Boltzmann transport equation is solved using the method of discrete ordinates, diffusion theory, or a special "combined P1" solution. In the discrete ordinates method, the primary mode of operation, balance equations are solved for the flow of particles moving in a set of discrete directions in each cell of a space mesh, and in each group of a multigroup energy mesh. Iterations are performed until all implicitness in the coupling of cells, directions, groups, and source regeneration has been resolved. Methods are available to accelerate convergence by space- dependent rebalance and by successive over-relaxation. Anisotropic cross sections can be expressed in a Legendre expansion of arbitrary order. Output data sets can be used to provide an accurate restart of a previous problem.

Special techniques are available to remove the effects of negative fluxes caused by the finite space and direction meshes, and of negative scattering due to truncation of the cross-section expansion. The space mesh can be described such that the number of first-dimension (I) intervals varies with the second dimension (J). The number of discrete directions can vary across the space mesh and with energy. The order of Legendre expansion can vary with cross- section set and with energy group.

Provision is made to treat sources resulting from the first collision of particles from a point source. In this case, flux due to uncollided particles is included in the output edits.

Direction sets can be biased, with more discrete direction segments per unit solid angle in some directions than in others.

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

External force fields or non linear effects cannot be treated. Flexible dimensioning is used throughout, so that no restrictions are imposed on individual problem parameters. Certain options, especially diffusion and P1 theories, are not compatible with variable mesh and quadrature problems.

DOT-4/VE: The vectorized algorithm is not used with variable mesh and quadrature problems.

External force fields or non linear effects cannot be treated. Flexible dimensioning is used throughout, so that no restrictions are imposed on individual problem parameters. Certain options, especially diffusion and P1 theories, are not compatible with variable mesh and quadrature problems.

DOT-4/VE: The vectorized algorithm is not used with variable mesh and quadrature problems.

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6. TYPICAL RUNNING TIME

Running time is roughly proportional to:

Flux work units (FWU) = number of space mesh cells x number of

directions x number of energy groups x

number of iterations per group.

Depending on the options chosen, a rate of 1.3 to 2.3 million FWU per minute on the IBM 360/195 is typical. Thus, a very large problem with 5000 space cells, 48 directions, 50 energy groups, and 10 iterations per group would require roughly 1 to 1.5 hours fo 360/195 CPU time.

Running time is roughly proportional to:

Flux work units (FWU) = number of space mesh cells x number of

directions x number of energy groups x

number of iterations per group.

Depending on the options chosen, a rate of 1.3 to 2.3 million FWU per minute on the IBM 360/195 is typical. Thus, a very large problem with 5000 space cells, 48 directions, 50 energy groups, and 10 iterations per group would require roughly 1 to 1.5 hours fo 360/195 CPU time.

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CCC-0320/04

GIP Cross-section preparationGRTUNCL First-collision source generation

RTFLUM Flux edits and conversion

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10. REFERENCES

- W.A. Rhoades and F.R. Mynatt:

The DOT-III Two-Dimensional Discrete Ordinates Transport Code

ORNL-TM-4280 (September 1973)

- F.R. Mynatt, F.J. Muckenthaler and P.N. Stevens:

Development of a Two-Dimensional Discrete Ordinates Transport

Theory for Radiation Shielding

CTC-INF-952 (August 1969)

- R. Douglas O'Dell and Raymond E. Alcouffe:

Transport Calculations for Nuclear Analyses: Theory and

Guidelines for Effective Use of Transport Codes

LA-10983-MS and UC-32 (September 1987)

- B. Barbucci, G. Mariotti:

Development of a Vectorized Version of the DOT Code for an

IBM 2090/200 VF Computer.

Proc. of 7th Int. Conf on Radiation Shielding,

Bournemouth (UK), 1988

- W.A. Rhoades and F.R. Mynatt:

The DOT-III Two-Dimensional Discrete Ordinates Transport Code

ORNL-TM-4280 (September 1973)

- F.R. Mynatt, F.J. Muckenthaler and P.N. Stevens:

Development of a Two-Dimensional Discrete Ordinates Transport

Theory for Radiation Shielding

CTC-INF-952 (August 1969)

- R. Douglas O'Dell and Raymond E. Alcouffe:

Transport Calculations for Nuclear Analyses: Theory and

Guidelines for Effective Use of Transport Codes

LA-10983-MS and UC-32 (September 1987)

- B. Barbucci, G. Mariotti:

Development of a Vectorized Version of the DOT Code for an

IBM 2090/200 VF Computer.

Proc. of 7th Int. Conf on Radiation Shielding,

Bournemouth (UK), 1988

CCC-0320/04, included references:

- W.A. Rhoades:Informal Notes (October 1979)

- W.A. Rhoades, D.B. Simpson, R.L. Childs and W.W. Engle Jr.:

The DOT-4 Two Dimensional, Discrete-Ordinates Transport Code with

Space-Dependent Mesh and Quadrature.

ORNL/TM-6529 (August 1978)

- DOT-4 Problem Set Descriptions

(April 1978)

- W.A. Rhoades:

RTFLUM - A Module for Converting, Expanding, and Editing

Standard Flux Files.

(April 1978)

- W.A. Rhoades:

The GIP Program for Preparation of Group-Organized

Cross Sections Libraries

(April 1978)

- ITOM - A Module to Convert ISOTXS Files to MATXS Format

(April 1978)

- W.A. Rhoades:

The FBSAM Data Transmission Package for IBM 360/370 Computers.

ORNL/TM-5199 (January 1976)

- D.B. Simpson and W.A. Rhoades:

The CFLAG Code

(April 1978)

- W.A. Rhoades:

The DOT-IV Variable Mesh Discrete Ordinates Transport Code.

Preprint of Paper 5 of Session P2 to be Included in Proceedings

of 5th International Conference on Reactor Shielding, Knoxville

(April 18-22, 1977)

- W.A. Rhoades:

Discrete Ordinates System Note 5 on "Space-Dependent

Rebalance Parameters (September 1978)

- W.A. Rhoades, R.L. Childs and W.W. Engle, Jr.:

Comparison of Rebalance Stabilization Methods for Two-Dimensional

Transport Calculations.

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11. MACHINE REQUIREMENTS

Memory must be approximately 50,000 words for a small problem, expanding wht problem size. External data storage must be provided for 8 scratch files, of which 4 must be direct (random) access. User-supplied input and output data files must be supplied on sequential-access devices, e.g. tapes or equivalent.

CCC-320/02: Main storage requirements to execute the test case on CDC CYBER 170/740 are 220,600 (octal) words.

Memory must be approximately 50,000 words for a small problem, expanding wht problem size. External data storage must be provided for 8 scratch files, of which 4 must be direct (random) access. User-supplied input and output data files must be supplied on sequential-access devices, e.g. tapes or equivalent.

CCC-320/02: Main storage requirements to execute the test case on CDC CYBER 170/740 are 220,600 (octal) words.

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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

The IBM version uses OS version 21. No special requirements are made of the operating system. Two types of overlay facility can be used if available.

CCC-320/02: The test case has been executed by NEA-DB on CDC CYBER 170/740 under the NOS 4.1 operating system.

The IBM version uses OS version 21. No special requirements are made of the operating system. Two types of overlay facility can be used if available.

CCC-320/02: The test case has been executed by NEA-DB on CDC CYBER 170/740 under the NOS 4.1 operating system.

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CCC-0320/04

File name | File description | Records |
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CCC0320_04.003 | DOT-4.2 INFORMATION FILE | 46 |

CCC0320_04.004 | DOT-4.2 SOURCE (FORTRAN-4) | 11897 |

CCC0320_04.005 | DOT-4.2 SOURCE (ASSEMBLER) | 4094 |

CCC0320_04.006 | GIP SOURCE (FORTRAN-4) | 2464 |

CCC0320_04.007 | RTFLUM SOURCE (FORTRAN-4) | 2369 |

CCC0320_04.008 | ROUTINES NEEDED BY GIP, RTFLUM (ASSEMBLER) | 372 |

CCC0320_04.009 | JCL FOR JOB COMPILE,LINK,RUN | 1737 |

CCC0320_04.010 | DOT-4.2 PRINTED OUTPUT OF TEST CASES | 13720 |

Keywords: anisotropic scattering, discrete ordinate method, legendre polynomials, neutron transport theory, shielding, two-dimensional.