Computer Programs

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 |
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SIXTUS-2 | NEA-0905/01 | Tested | 19-SEP-1983 |

Machines used:

Package ID | Orig. computer | Test computer |
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NEA-0905/01 | CDC CYBER 174 | CDC CYBER 174 |

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4. METHOD OF SOLUTION

A solution in terms of face averaged partial currents and node averaged flux is obtained from the response matrix equations for irreducible symmetry components of partial currents at nodal interfaces. The response matrix elements are generated from the base set of analytical fundamental solutions spanned on an exact spectrum of the node reaction matrix. The RM equations are solved by an explicit scheme in which all the nodes are scanned in a pre- scribed order and the energy group vector of outgoing currents is used to form the irreducible symmetry components of the energy group vector of incoming currents for neighboring nodes. The effective multiplication constant is iterated directly from the neutron balance. Because the method does not use a conventional group-by- group solution but deals with all energy groups simultaneously, the presence of upscattering does not influence adversely the convergence rate. This iteration is accelerated by Lyusternik-Wagner extrapolation of currents and flux values.

A solution in terms of face averaged partial currents and node averaged flux is obtained from the response matrix equations for irreducible symmetry components of partial currents at nodal interfaces. The response matrix elements are generated from the base set of analytical fundamental solutions spanned on an exact spectrum of the node reaction matrix. The RM equations are solved by an explicit scheme in which all the nodes are scanned in a pre- scribed order and the energy group vector of outgoing currents is used to form the irreducible symmetry components of the energy group vector of incoming currents for neighboring nodes. The effective multiplication constant is iterated directly from the neutron balance. Because the method does not use a conventional group-by- group solution but deals with all energy groups simultaneously, the presence of upscattering does not influence adversely the convergence rate. This iteration is accelerated by Lyusternik-Wagner extrapolation of currents and flux values.

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

(1) The problem size designated LIM should not exceed 12000. This number, however, can be readily increased.

(2) External sources are not permitted, only eigenvalue (keff) solutions.

(3) Because of rounding error problems the number of energy groups should not exceed 10 for the present version of the program.

(1) The problem size designated LIM should not exceed 12000. This number, however, can be readily increased.

(2) External sources are not permitted, only eigenvalue (keff) solutions.

(3) Because of rounding error problems the number of energy groups should not exceed 10 for the present version of the program.

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6. TYPICAL RUNNING TIME

About 2.4 milliseconds of CP time on CDC6400 per one sweep, node and group. To reach an accuracy of the order of 10**(-7) for keff and fission source and 10**(-6) for nodal flux, the code requires 80 to 120 sweeps depending on the nature of the problem.

NEA-DB executed the test case on CDC CYBER 174 in 151 CPU seconds.

About 2.4 milliseconds of CP time on CDC6400 per one sweep, node and group. To reach an accuracy of the order of 10**(-7) for keff and fission source and 10**(-6) for nodal flux, the code requires 80 to 120 sweeps depending on the nature of the problem.

NEA-DB executed the test case on CDC CYBER 174 in 151 CPU seconds.

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10. REFERENCES

- J.J. Arkuszewski:

"A Solution to the Benchmark Problem ID9-A1 of the Benchmark

Problem Book"

EIR Internal Report TM-22-82-19 (1982)

- J.J. Arkuszewski:

"A Solution to the Benchmark Problem ID9-A1 of the Benchmark

Problem Book"

EIR Internal Report TM-22-82-19 (1982)

NEA-0905/01, included references:

- J.J. Arkuszewski:SIXTUS-2 - A Two Dimensional Multigroup Diffusion Theory Code in

Hexagonal Geometry. Part 1: Theory, Code Description and User's

Manual. EIR-Bericht 470 (September 1982).

- J.J. Arkuszewski:

SIXTUS-2 - A Two Dimensional Multigroup Diffusion Theory Code in

Hexagonal Geometry. Part 2: Code Validation.

EIR-Bericht 471 (September 1982).

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Package ID | Computer language |
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NEA-0905/01 | FORTRAN-IV EXTENDED |

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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

Installation of the program on computers with shorter than 60-bit word length may require a replacement of EISPACK routines for the algebraic eigenvalue problem of a real general matrix. The same pertains to the general matrix inversion algorithm (routine TRIX).

Installation of the program on computers with shorter than 60-bit word length may require a replacement of EISPACK routines for the algebraic eigenvalue problem of a real general matrix. The same pertains to the general matrix inversion algorithm (routine TRIX).

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NEA-0905/01

File name | File description | Records |
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NEA0905_01.003 | SIXTUS-2 INFORMATION FILE | 44 |

NEA0905_01.004 | SIXTUS-2 SOURCE CARD-IMAGES (FORTRAN-4) | 2394 |

NEA0905_01.005 | SIXTUS-2 JCL FOR TEST CASE EXECUTION | 22 |

NEA0905_01.006 | SIXTUS-2 INPUT DATA FOR TEST CASE | 82 |

NEA0905_01.007 | SIXTUS-2 OUTPUT OF TEST CASE | 1012 |

Keywords: diffusion equations, hexagonal configuration, multigroup theory, two-dimensional.