1. NAME AND TITLE OF DATA LIBRARY

CTR: 73-Group P₃ Coupled Neutron and Gamma-Ray Cross Sections for Fusion Reactor Calculations.

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAM

LIBGEN: A Computer Program to Generate an Unformatted Cross-Section Tape for Input to ANISN.

3. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

4. HISTORICAL BACKGROUND AND INFORMATION

The data in DLC-28/CTR were developed for calculating fluxes in conceptual fusion reactor designs. It is planned that the library will be improved and updated at frequent intervals.

5. APPLICATION OF THE DATA

The DLC-28/CTR library can be used for neutron and secondary gamma-ray transport in fusion reactor neutronics studies. The data were collapsed from a fine-group structure using a weighting function typical of the average spectrum in a fusion reactor blanket. Thus, the application of this data for problems not similar to the fusion reactor type should be done with caution.

The retrieval program supplied with the library can convert the data into cross-section input forms required for codes such as CCC-82/ANISN-CEA, CCC-89/DOT, and CCC-127/MORSE.

6. SOURCE AND SCOPE OF DATA

DLC-28/CTR is a coupled set of cross sections for materials typically considered for use in some conceptual fusion reactor neutronics studies. These materials include:

⁶Li, ⁷Li, Nb, C, Fe, Cu, LiH, Al₂O₃, Mg, H, O, Pb, Ta, V, and B.

In some cases, more than one data set is provided for a given material. These materials are identified and the difference between data sets for the same material are described in the packaged documentation.

With the exception of lead and boron, 100 energy-group neutron cross sections were obtained from ENDF/B or Defense Nuclear Agency data sets using PSR-13/SUPERTOG. A flux weighting of 1/E was used in SUPERTOG and all resonance nuclides were treated as infinitely dilute. The energy-group structure coincided with the GAM-II group structure for the top 99 groups, and the 100th group was a thermal group (a Maxwellian distribution was assumed).

For lead and boron, the GAM-II library at Oak Ridge National Laboratory was employed to obtain the 100-group neutron cross sections.

SMUG, an updated version of MUG, was used to calculate 21 energy-group gamma-ray transport cross sections for all nuclides except lead and boron. The gamma-ray transport cross sections for lead and boron are from MUG.

Secondary gamma-ray production cross sections for 100 neutron groups and 21 gamma-ray groups were obtained from several data bases.

A coupled 100 neutron energy-group and 21 gamma-ray energy-group cross section set was formed and then collapsed to 52 neutron groups + 21 gamma-ray groups using the group collapsing feature of the ANISN code. The spectrum used for the collapsing was, therefore, a spatial average of the energy distribution in a fusion reactor blanket.

The energy-group structures used are given in the packaged documentation. A P₃ Legendre expansion was used to represent neutron elastic scattering and photon Compton scattering.

7. DISCUSSION OF THE DATA RETRIEVAL PROGRAM

LIBGEN is a modified version of the Library Generation Routine available in the CCC-82/ANISN code package. This version reads the card image CTR tape and converts it into an unformatted library tape for direct use in CCC-82/ANISN-CEA, CCC-89/DOT, and CCC-127/MORSE.

8. DATA FORMAT AND COMPUTER

BCD/EBCDIC card images; IBM 360/370.

9. TYPICAL RUNNING TIME

On an IBM 360/91 computer, it requires 45 seconds to convert to an unformatted tape using the retrieval program.

10. REFERENCES

J. T. Kriese, "Coupled Neutron and Gamma-Ray Cross Section Sets for Fusion Reactor Calculations," ORNL-TM-4277 (August 1973).

"LIBGEN: A Special Version of the ANISN Library Generation Routine."

11. CONTENTS OF LIBRARY

Included are the referenced documents and one (1.2MB) DOS diskette which contains the cross section data, the ANISN Library Routine plus sample problem input and output.

12. DATE OF ABSTRACT

September 1973; reviewed May 1984.