1. NAME AND TITLE OF DATA LIBRARY

COBB: 123-Group Neutron Cross Section Data Generated from ENDF/B-II Data for Use in the XSDRN Discrete Ordinates Spectral Averaging Code.

2. NAME AND TITLE OF DATA RETRIEVAL PROGRAMS

JUANITA: A Program to Convert from Formatted to Unformatted XSDRN Master Library Tapes and Vice Versa.

SUP: A Program to Update an Unformatted XSDRN Master Library Tape.

SECS: A Program to Edit an Unformatted XSDRN Master Library Tape.

3. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

4. HISTORICAL BACKGROUND AND INFORMATION

This library was compiled during the course of investigations by W. R. Cobb of the Reactor Division at Oak Ridge National Laboratory. Portions of the data included were prepared by R. Q. Wright of the ORNL Mathematics Division.

5. APPLICATION OF THE DATA

DLC-16/COBB is intended to be a source of evaluated data for the cross-section preparation code CCC-123/XSDRN. It supplements, rather than replaces, the existing XSDRN master library which is distributed with the code package.

6. SOURCE AND SCOPE OF DATA

The library contains ENDF/B version II cross sections processed through several steps (primarily by PSR-13/SUPERTOG) into the standard XSDRN 123-group energy structure. These steps are:

a. Process fast cross sections with PSR-13/SUPERTOG into standard 99-group GAM-II energy structure (14 MeV - 0.414 eV), using a "1/E" weighting function, and produce a GAM-II tape. (This step was performed by R. Q. Wright, Mathematics Division, ORNL.)

b. Process thermal cross sections with PSR-13/SUPERTOG into standard 30-group THERMOS energy group structure (1.86 eV - 0.0047 eV), using a Maxwell-Boltzmann distribution with temperature 293° K as a weighting function for E < 0.125 eV coupled to a "1/E" weighting function for 0.125 eV < E < 1.86 eV.

c. Compute room temperature free-gas kernels, using the THERMOS tape-making program, and combine with results of step b into a THERMOS tape.

d. Combine the GAM-II and THERMOS tapes into a 123-group XSDRN tape using an unpublished ORNL code written specifically for this purpose.

This library contains data for a P3 approximation to the angular scattering for all ENDF/B version II nuclides except hydrogen; however, an older set of cross sections for hydrogen in water were included for completeness. Nuclides whose cross sections are not given by ENDF/B in elemental form have been processed both as resonance and infinite dilute cross sections.

The XSDRN I.D. numbers of nuclides on this tape are of the form

where Z is the atomic number of the element, A is the atomic weight of the isotope, and S is 0 or 1, depending on whether the cross sections are in the form of resonance parameters or are given at infinite dilution. An I.D. number for which A=0 implies that the cross sections are for the naturally occurring element.

The library contains data for:

H, D, He, ⁹Be, ¹⁰B, ¹²C, ¹⁶O, ²³Na*, Mg, ²⁷Al, Ti, V, Cr, ⁵⁵Mn*, Fe, Ni, Cu, ⁶³Cu*, ⁶⁵Cu*, ⁹³Nb*, Mo, ¹³⁵Xe, ¹⁴⁹Sm*, ¹⁵¹Eu*, ¹⁵³Eu*, Gd, ¹⁶⁴Dy*, ¹⁷⁵Lu*, ¹⁷⁶Lu*, ¹⁸²W**, ¹⁸³W**, ¹⁸⁴W**, ¹⁸⁶W**, ¹⁸⁵Re*, ¹⁸⁷Re*, ¹⁹⁷Au*, ²³³U, ²³⁴U*, ²³⁵U*, ²³⁶U*, ²³⁸U*, ²³⁷Np*, ²³⁹Pu*, ²⁴⁰Pu*, ²⁴¹Pu*, ²⁴²Pu*, ²⁴¹Am*, ²⁴³Am*, ²⁴⁴Cm*.

Two XSDRN I.D. numbers given, one for resonance nuclide treatment and one for infinite dilution treatment.

** Resonance nuclide treatment only.

7. DISCUSSION OF DATA RETRIEVAL PROGRAMS

Three programs are provided for manipulating DLC-16/COBB data; these were written by N. M. Greene of ORNL for use with data for the XSDRN discrete ordinates spectral averaging code. The first code, JUANITA, will convert an unformatted XSDRN master library tape to a formatted one, or vice versa. XSDRN requires an unformatted (binary) tape for input, but DLC-16/COBB has been put in formatted (BCD card images) form for easy transmittal between installations. The second code, SUP, can be used to update and the third code, SECS, to edit an unformatted XSDRN master library tape.

8. DATA FORMAT COMPUTER

BCD card images; IBM 360/370.

9. TYPICAL RUNNING TIME

JUANITA: On the IBM 360/91 computer, compilation and execution time for converting the entire DLC-16/COBB library from an unformatted to a formatted tape took 2 minutes. No study has been made by RSIC of typical running times for SUP or SECS.

10. REFERENCES

W. R. Cobb, "New XSDRN Library," Informal note (November 1970).

N. M. Greene, "JUANITA: Instructions for Master Cross Section Library Converter Program," Informal note (January 1971). "XSDRN Tape Format," Informal note.

N. M. Greene, "SUP: Input Requirements for XSDRN Master Cross Section Library Update Program," Informal note.

N. M. Greene, "SECS: Instructions for Master Cross Section Library Listing Code," Informal note.

11. CONTENTS OF LIBRARY

Included are the referenced documents and one tape cartridge in TAR format which contains the entire library plus the retrieval programs.

12. DATE OF ABSTRACT

January 1971; reviewed May 1984.