last modified: 04-SEP-1992 | catalog | categories | new | search |

NEA-1279 MODICO.

MODICO, 1-D Time-Dependent 1 Group, 2 Group Neutron Diffusion with Delayed Neutron Precursors

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1. NAME OR DESIGNATION OF PROGRAM:  MODICO.
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2. COMPUTERS
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Program name Package id Status Status date
MODICO NEA-1279/01 Tested 04-SEP-1992

Machines used:

Package ID Orig. computer Test computer
NEA-1279/01 IBM 3081 DEC VAX 8810
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3. DESCRIPTION OF PROGRAM OR FUNCTION

The program solves the 1-D time-dependent one and two group coarse-mesh neutron diffusion equations, coupled with the equations for the delayed-neutron precursor, in plane geometry.
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4. METHOD OF SOLUTION

The program is based on a simple coarse-mesh cubic approximation formula for the spatial behaviour of the flux inside each interval. An implicit scheme (the time-integrated method) is used for the advancement of the solution. The resulting (block three-diagonal) matrix is inverted at each time step by Thomas' method.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Number of coarse- mesh intervals LE 80; number of material regions LE 10; number of delayed-neutron precursor groups LE 10. Typical mesh sizes range from 5 cm to 20 cm; typical step length (non-prompt critical transients) ranges from 0.005 to 0.1 seconds.
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6. TYPICAL RUNNING TIME

Each time step requires about 0.001 seconds for each spatial interval (with 2 energy groups and 6 delayed neutron groups), on the IBM 3081.
NEA-1279/01
NEADB compiled the program on a DEC VAX 8810 computer and ran the three test cases included in this package in about 10 seconds of CPU time.
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7. UNUSUAL FEATURES OF THE PROGRAM

Analytical quasi-static treatment  of top and bottom reflectors (optional). Time step size automatically adapted to the flux trend (optional).
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8. RELATED AND AUXILIARY PROGRAMS:
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9. STATUS
Package ID Status date Status
NEA-1279/01 04-SEP-1992 Tested at NEADB
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10. REFERENCES

- P. Camiciola, D. Cundari, B. Montagini:
  "A-Course-Mesh Method for 1-D Reactor Kinetics"
  Ann. Nucl. Energy, 13,11, p. 629 (1986)
NEA-1279/01, included references:
- P. Camiciola, D. Cundari and B. Montagnini:
  MODICO - A Coarse Mesh Code for One-Dimensional Reactor Kinetics.
  Draft Report (1989)
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11. MACHINE REQUIREMENTS

MODICO uses three logical units. A problem having 80 meshes can be run using as much as 350K bytes of fast memory.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NEA-1279/01 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:
NEA-1279/01
VMS 5.3 (VAX 8810).
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHORS

- P. Camiciola
  ENEA DISP
  via Vitaliano Brancati 48
  00198 ROME, Italy
- D. Cundari
  ANSALDO S.p.A.
  via G. D'Annunzio 113
  16121 GENOVA, Italy
- B. Montagnini
  Dipartimento di Costruzioni Mecchaniche e Nucleari
  dell' Universita di Pisa
  via Diotisalvi 2
  56100 PISA, Italy
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16. MATERIAL AVAILABLE
NEA-1279/01
File name File description Records
NEA1279_01.001 This information file 52
NEA1279_01.002 JCL and control information 28
NEA1279_01.003 Orig. JCL to run MODICO at ENEA DISP 31
NEA1279_01.004 MODICO FORTRAN source 2092
NEA1279_01.005 Aux. FORTRAN subroutine for test problem 1 16
NEA1279_01.006 Aux. FORTRAN subroutine for test problem 2 57
NEA1279_01.007 Aux. FORTRAN subroutine for test problem 3 49
NEA1279_01.008 Sample problem input 1 18
NEA1279_01.009 Sample problem input 2 18
NEA1279_01.010 Sample problem input 3 18
NEA1279_01.011 Sample problem output 1 147
NEA1279_01.012 Sample problem output 2 183
NEA1279_01.013 Sample problem output 3 139
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17. CATEGORIES
  • C. Static Design Studies
  • F. Space - Time Kinetics, Coupled Neutronics - Hydrodynamics - Thermodynamics

Keywords: delayed neutrons, diffusion, one-dimensional, reactor kinetics, space-time.