1. NAME AND TITLE

FEDGROUP-R: Multigroup Neutron Cross Section Processing System from Data in ENDF/B Format.

2. CONTRIBUTOR

Nuclear Research Institute, Rez near Prague, Czechoslovakia.

3. CODING LANGUAGE AND COMPUTER

Fortran on IBM PC and compatibles (P00349/MNYCP/00) with implementations on DEC VAX and Robotron 1040 (IBM type).

4. NATURE OF PROBLEM SOLVED

Evaluated nuclear data from files in ENDF/B format are processed to prepare group cross sections for reactor physics calculations. In particular, data for ABBN and WIMS group libraries can be generated. Program LIBCOM (as a part of FEDGROUP-R) is used to compile calculated group constants into a file with desired format.

5. METHOD OF SOLUTION

FEDGROUP-R has been developed on the basis of programs FEDGROUP-2 and FEDGROUP-3 (PSR-123) and includes some parts of those codes, conserves the scheme of processing data in two steps, structure and format of some data files. There are some completely new modules included, in particular the module for calculating cross sections in the resonance region, including calculation of self-shielded quantities. In the calculation of cross sections in the resonance region in general the methods described for LINEAR and RECENT codes (by D.E. Cullen, PSR-351/PREPRO-94) have been applied. Some simplified schemes of calculation are still included as an option in order that the running time can be reduced if necessary.

6. RESTRICTIONS OR LIMITATIONS

Resonance parameters can be processed using only Breit-Wigner (both single- and multi-level) formalism. Doppler effect is calculated approximately, using functions. Scattering matrices in thermal region cannot be calculated (only calculation for nucleus at rest is available). Data from MF=6 files of ENDF/B-VI are not processed.

7. TYPICAL RUNNING TIME

For the sample problem run time was 4 minutes 21 seconds on a Norhtgate 486/66 using the included executable and sample data.

8. COMPUTER HARDWARE REQUIREMENTS

Program was operated on the following computers: EC 1040 (as IBM 360), DEC VAX 3900, PC AT 286/287 (basic memory of 640 kb is not sufficient for some tasks).

9. COMPUTER SOFTWARE REQUIREMENTS

Standard compilers for FORTRAN on IBM OS/360 and DEC VMS systems were used. Executables included in the package for both FEDGROUP-R and LIBCOM were created on a Northgate 486/66 running MS-DOS 6.2 using MS FORTRAN v5.1. The system has also been run on PC's under OS/2 which is more suitable for complex tasks.

10. REFERENCES

a: included in documentation:

A. Holubar, "FEDGROUP-R: A Program for Calculation of Group Cross Sections on the Basis of Evaluated Nuclear Data Libraries," Nuclear Research Institute, UJV 9683-R (1992).

b: background information:

P. Vertes, "FEDGROUP-3: A Program System for Processing Evaluated Nuclear Data in ENDF/B, KEDAK, or UKNDL Format to Constants to be Used in Reactor Physics Calculation," KFKI-1981-34 (1981). (RSIC: PSR-123/FEDGROUP-3).

11. CONTENTS OF CODE PACKAGE

The referenced document in 10.a. and 1 DS/HD 3.5" (1.44 MB) diskette are included. The DOS diskette contains Fortran 77 source files, a DOS executable, sample input and output, and an information file written in self-extracting compressed DOS files.

12. DATE OF ABSTRACT

June 1995.