1. NAME AND TITLE

CRESO: Resonance Data-handling Code System.

DATA LIBRARY

ZRDATA: Cross Sections for Zirconium-91 FROM CNEN/CEA Evaluations.

2. CONTRIBUTOR

Comitato Nazionale Energia Nucleare, Bologna, Italy, through the OECD NEA Data Bank, Gif-sur-Yvette, France.

3. CODING LANGUAGE AND COMPUTER

Fortran IV and Assembler Language; IBM 370/160 and IBM 3081.

4. NATURE OF PROBLEM SOLVED

CRESO calculates energy-dependent pointwise neutron cross sections from resonance parameters read either from cards or from an ENDF/B tape. Both versions IV and V are accepted. It properly handles the following formalisms: single and multilevel Breit-Wigner, Reich-Moore, Adler-Adler unresolved resonances with all energy-independent and all energy-dependent parameters and with energy-dependent fission widths.

5. METHOD OF SOLUTION

In the resolved resonance region, CRESO calculates the cross section at a set of internally generated energy grid points. The grid is obtained by successively subdividing the intervals between resonances until the cross section estimated from an interpolation formula is sufficiently close to that calculated from resonance parameters. The maximum number of sub-intervals between each resonance is defined by the user. In the unresolved resonance region, cross sections are calculated at a series of logarithmically spaced energies. The entire energy grid covers the range defined by ENDF/B rules; however, it may be extended by inputting additional energy points.

6. RESTRICTIONS OR LIMITATIONS

The maximum number of energy points for any reaction is 5000. If this limit is reached, the calculation proceeds by clearing the buffers and renumbering the points, but it is then no longer possible to plot all the data or generate an output file in ENDF/B format. Doppler broadening is not reliable in this event.

7. TYPICAL RUNNING TIME

A sample problem calculating the elastic scattering, capture and total cross section of zirconium-91 in the energy range 10 MeV to 10 keV requires 6 seconds CPU time on an IBM 370/168.

8. COMPUTER HARDWARE REQUIREMENTS

CRESO requires 240 K bytes on an IBM 370/168 computer. The program requires two scratch devices and two additional decimal units for input and output of cross section data. CRESO was developed on an IBM 370/168 computer and has been tested on an IBM 3081 computer.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran IV compiler is required.

CRESO includes plotting routines designed for a CALCOMP unit but communicates with graphic software through an interface which can be addressed to any device.

10. REFERENCE

G. C. Panini, "CRESO - A Computer Code for Resonance Data Handling," CNEN-RT/FI(81)30 (November 1981).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source code and sample problem input and output.

12. DATE OF ABSTRACT

February 1983; updated March 1984.