Computer Programs

NAME, COMPUTER, PROBLEM, SOLUTION, RESTRICTIONS, CPU, FEATURES, AUXILIARIES, STATUS, REFERENCES, REQUIREMENTS, LANGUAGE, OPERATING SYSTEM, OTHER RESTRICTIONS, AUTHOR, MATERIAL, CATEGORIES

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Program name | Package id | Status | Status date |
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FX2-TH | NESC0862/001 | Tested | 26-MAY-1981 |

Machines used:

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

NESC0862/001 | IBM 3033 | IBM 3033 |

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3. DESCRIPTION OF PROGRAM OR FUNCTION

FX2-TH solves the steady-state and time-dependent two-dimensional multigroup neutron diffusion equations with thermal and hydraulic feedback. The following geometry options are available: x, r, x-y, r-z, theta-r, and triangular. FX2-TH contains two basic thermal and hydraulic models: a simple adiabatic fuel temperature calculation and a more detailed model consisting of an explicit representation of fuel pin, gap, clad, and coolant. FX2-TH allows feedback effects from both fuel temperature (Doppler) and coolant temperature (density) changes.

The code is designed for nuclear reactor analysis.

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4. METHODS

The multigroup diffusion equations are discretized in space using mesh-centered finite differences. The steady-state solution of these equations is found by accelerating a fission source iteration through the use of Chebyshev polynomials. The neutron fluxes for each energy group at each power iteration are found using the successive line over-relaxation method. A consistent set of steady-state conditions is established by iterating between the steady-state neutronics and thermal-hydraulics equations. The time-dependent solution is then found using the improved quasistatic method. The shape calculations required by the quasistatic method utilize the same calculational methods as described above for the steady-state calculation.

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Variable dimensioning is used throughout the program so that computer storage requirements depend on a variety of problem parameters. The amount of memory required can range from 300K bytes for a small problem up to the maximum limit of computer storage for very large problems.

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10. REFERENCES

R. Douglas O'Dell,

Standard Interface Files and Procedures for Reactor Physics Codes, Version IV, LA-6941-MS.D.A. Meneley, Gary Leaf, A.J. Lindeman, T.A. Daly, and W.T. Sha,

A Kinetics Model for Fast Reactor Analysis in Two Dimensions, Dynamics of Nuclear Systems, The University of Arizona Press, Tucson, Arizona, pp.483-500, 1972.

NESC0862/001, included references:

- R.A. Shober, T.A. Daly, and D.R. Ferguson:FX2-TH - A Two-dimensional Nuclear Reactor Kinetics Code with Thermal-Hydraulic

Feedback, ANL-78-97 (October 1978).

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11. HARDWARE REQUIREMENTS

FX2-TH will dynamically allocate problem variables either on disk or in computer memory depending on the total amount of computer memory available. For any problem a certain minimum amount of memory is required; this amount is dependent on the size of the problem. In general, FX2-TH operates more efficiently if sufficient computer memory is available to retain most of the variables permanently. The sample problem executed by NESC required 900K bytes of memory.

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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

FX2-TH may be compiled using either FORTRAN H or Extended compilers with OPT=2 optimization. Skeleton versions of standard routines as specified by the Committee of Computer Code Coordination (CCCC) and in the document LA-6941-MS are part of the FX2-TH package. These standard routines are REED, RITE, LRED, LRIT, TIMER, and SEEK; they may be replaced by suitable local environment routines for enhanced operation.

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NESC0862/001

File name | File description | Records |
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NESC0862_01.001 | INFORMATION FILE | 103 |

NESC0862_01.002 | FX2-TH FORTRAN SOURCE (F4,EBCDIC) | 38175 |

NESC0862_01.003 | FX2-TH ASSEMBLER SOURCE | 547 |

NESC0862_01.004 | OVERLAY CARDS | 68 |

NESC0862_01.005 | SAMPLE PROBLEM 3 INPUT DATA | 283 |

NESC0862_01.006 | A.ISO MICROSCOPIC CROSS SECTIONS | 38 |

NESC0862_01.007 | A.DLA DELAYED NEUTRON PARAMETERS | 1 |

NESC0862_01.008 | MANUAL DOCUMENTATION | 4891 |

NESC0862_01.009 | PRINTED OUTPUT OF SAMPLE PROBLEM | 5885 |

NESC0862_01.010 | JCL TO RUN FX2-TH AT NEA/DATA BANK | 295 |

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- F. Space - Time Kinetics, Coupled Neutronics - Hydrodynamics - Thermodynamics

Keywords: diffusion equations, feedback, hydraulics, kinetics, multigroup theory, thermal conduction, two-dimensional.