1. NAME AND TITLE

LEOPARD: A Spectrum-Dependent Non-Spatial Fuel Depletion Code System.

AUXILIARY ROUTINE

SPS: SPOTS4 Source Routine.

DATA LIBRARY

SGDL: SPOTS4 Group Data Library.

2. CONTRIBUTORS

Electric Power Research Institute, Palo Alto, California.

Westinghouse Electric Corporation, Pittsburgh, Pennsylvania.

Battelle Pacific Northwest Laboratories, Richland, Washington.

Korea Advanced Energy Research Institute through the Nuclear Data Services of the International Atomic Energy Agency, Vienna, Austria.

Georgia Institute of Technology, Atlanta, Georgia.

3. CODING LANGUAGE AND COMPUTER

Fortran IV; CDC CYBER-175 (A) and IBM PC (B).

4. NATURE OF PROBLEM SOLVED

LEOPARD determines fast and thermal spectra, using only basic geometry and temperature data, based on a modified MUFT-SOFOCATE model. The code optionally computes fuel depletion effects for a dimensionless reactor and recomputes the spectra before each discrete burnup step.

LEOPARD will automate the spectra calculations defined by Strawbridge in WCAP-3269-25 and will account for the variation of neutron spectra with fuel depletion. The latter task is achieved by performing the spectra calculations, calculating fuel depletion for a given time increment, recalculating spectra, etc. The burnup calculations are non-spatial.

5. METHOD OF SOLUTION

The user supplies the reactor geometry, compositions and temperatures. The code temperature corrects the input data and computes number densities and three epithermal cross sections (for the fuel pellet, the clad and moderator, and the homogenized cell) to be used in the spectrum calculations.

LEOPARD assumes that every reactor contains a large array of unit fuel cells arranged in either a square lattice or a hexagonal lattice. Each unit cell contains one cylindrical fuel rod, a metallic clad around the fuel rod, and a moderator. In a real reactor this geometry is adequate within a large fuel bundle, but commonly several percent of the core is taken up by control rod followers, water slots, assembly cans, structure, etc. LEOPARD accounts for this by allowing a fictitious region to be defined and described in a manner entirely analogous to the description of the ``real'' regions within the unit fuel cell. Spectrum calculations are then done on an ``equivalent'' unit cell.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

Running time for LEOPARD is one-two complete spectra calculations per minute on the CYBER. The sample input problem LEOIN took 2 minutes on the IBM PC/XT; the sample burnup problem PS7 took about 20 minutes.

8. COMPUTER HARDWARE REQUIREMENTS

The code is operable on the CDC CYBER-175 or IBM PC.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required. The IBM PC version uses the Microsoft Fortran Version 4.1 compiler and can be compiled with or without a math coprocessor. The executable file distributed by RSIC does not require the coprocessor.

10. REFERENCES

Dale Lancaster, information on input modification required for microcomputer version (March 1989).

B. R. Leonard, Jr., D. A. Kottwitz, U. P. Jenquin, K. B. Stewart, and C. M. Heeb, "Cross-Section Standardization for Thermal Power Reactors," EPRI 221 (July 1975).

R. F. Barry, "LEOPARD A Spectrum Dependent Non-Spatial Depletion Code for the IBM-7094," WCAP-3269-26 (September 1963).

Jung-Do Kim and Jong Tai Lee, "SPOTS4 Group Data Library and Computer Code Preparing ENDF/B-IV Data for Input to LEOPARD," IAEA-NDS-36 Rev. 0 (September 1981).

Jung-Do Kim and Jong Tai Lee, "Benchmark Test and Adjustment of an Updated Library from ENDF/B-IV," Draft paper submitted to Journal of Korean Nuclear Society (May 1981).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source code, auxiliary routine and multigroup libraries. The PC version (B) is transmitted on one 5.25 inch DS/DD (360 K) diskette.

12. DATE OF ABSTRACT

January 1982; revised December 1983 and March 1989.