1. NAME AND TITLE OF DATA LIBRARY

GROUPSTRUCTURES: Standard Energy Group Structures Of Cross Section Libraries For Reactor Shielding, Reactor Cell and Fusion Neutronics Applications: VITAMIN-J, ECCO-33, ECCO-2000 and XMAS

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAMS

A computer program is provided with the package for producing a weighting spectrum for group averaging purposes.

3. CONTRIBUTORS

NEA Data Bank, Gif-sur-Yvette Cedex, France.

4. HISTORICAL BACKGROUND AND INFORMATION

Within the International Evaluation Cooperation, four energy group structures for multigroup cross section libraries were defined and adopted. The main purpose is to facilitate the inter-laboratory benchmarking of the evaluated files: ENDF/B-VI, JEF-2, JENDL-3.

5. APPLICATION OF THE DATA

The energy group structures were created for use in reactor shielding, reactor cell and fusion neutronics applications.

6. SOURCE AND SCOPE OF DATA

The four group structures are described herein.

The VITAMIN-J group structure was defined in the framework of the JEF-1 benchmarking for use in reactor shielding and fusion neutronics application. It is based on the group structures of VITAMIN-C (DLC-41) and VITAMIN-E (DLC-113). VITAMIN-J has 175 neutron groups and 42 gamma groups.

ECCO-33 is a 33-group structure containing a subset of the VITAMIN-J energy group boundaries. It is aimed at benchmark studies of fast critical experiments.

XMAS is a 172-group neutron structure designed for thermal and intermediate energy reactor cell calculations.

ECCO-2000 is a 1968-group neutron structure containing a subset of both the VITAMIN-J and XMAS energy group boundaries. It is aimed at fine group reactor cell calculations for fast, intermediate and thermal reactor applications. The basic lethargy grid is 1/120 with a few exceptions from 20 MeV to 5eV.

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAMS

A computer code for producing the weighting function in tabular form is provided.

8. DATA FORMAT AND COMPUTER

Card images; IBM 3090, VAX 8810.

9. TYPICAL RUNNING TIME

The test problem took about 4 seconds of CPU time on a VAX 8810.

10. REFERENCES

a. Included in the package:

Enrico Sartori. Standard Energy Group Structures Of Cross Section Libraries For Reactor Shielding, Reactor Cell and Fusion Neutronics Applications: VITAMIN-J, ECCO-33, ECCO-2000 and XMAS, JEF/DOC-315, Revision 3, NEA Data Bank, Gif-sur-Yvette Cedex, France, December 11, 1990.

11. CONTENTS OF PACKAGE

The package contains reference listed above and the data library. The data library is transmitted on one DS/DD 5.25-inch diskette (360 kb).

12. DATE OF ABSTRACT

February 1991.