1. NAME AND TITLE
URR: Calculates Resonance Neutron Cross-Section Probability Tables, Bondarenko Self-Shielding Factors and Self- Indication Ratios for Fissile and Fertile Nuclides.
Oak Ridge National Laboratory, Oak Ridge, Tennessee.
3. CODING LANGUAGE AND COMPUTER
Fortran 77; VAX family.
4. NATURE OF PROBLEM SOLVED
URR was developed to calculate cross-section probability tables, Bondarenko self-shielding factors,
and self-indication ratios for fertile and fissile isotopes in the unresolved resonance region.
5. METHOD OF SOLUTION
URR uses Monte Carlo techniques to select appropriate resonance parameters and to compute the
cross sections at the desired reference energy. The neutron cross sections are calculated by the single-level Breit-Wigner formalism with s-, p-, and d-wave contributions. The cross-section probability
tables are constructed by sampling the Doppler broadened cross-section. The various self-shielded
factors are computed numerically as Lebesgue integrals over the cross-section probability tables.
6. RESTRICTIONS OR LIMITATIONS
7. TYPICAL RUNNING TIME
URR is interactive and executes in a few seconds.
8. COMPUTER HARDWARE REQUIREMENTS
The code runs on any VAX computer.
9. COMPUTER SOFTWARE REQUIREMENTS
The code was written in Fortran 77 and was tested on the VAX 6000 under the VMS operating
L. C. Leal, G. de Saussure and R. B. Perez, "URR Computer Code: A Code to Calculate
Resonance Neutron Cross-Section Probability Tables, Bondarenko Self-Shielding Factors and Self-Indication Ratios for Fissile and Fertile Nuclides," ORNL/TM-11297 (August 1989).
11. CONTENTS OF CODE PACKAGE
Included are the referenced document and one (360 K) DOS diskette including the source and
12. DATE OF ABSTRACT
KEYWORDS: MONTE CARLO; INTERACTIVE, ON-LINE; NEUTRON CROSS SECTION PROCESSING