1. NAME AND TITLE

FORSS: A Sensitivity and Uncertainty Analysis Code System.

2. CONTRIBUTOR

Oak Ridge National Laboratory, Oak Ridge, Tennessee.

3. CODING LANGUAGE AND COMPUTER

Fortran IV, Assembler language; IBM 360/370 (A) and CDC (B).

4. NATURE OF PROBLEM SOLVED

FORSS is a code system used to study relationships between nuclear reaction cross sections, integral experiments, reactor performance parameter predictions, and associated uncertainties. Results of integral experiments may be incorporated through FORSS to improve uncertainty estimates of reactor performance for devices being designed. The FORSS development is based upon transport theory (there is a diffusion theory option) so that the same tool is applicable to both shielding and reactor core problems in multidimensional geometry.

5. METHOD OF SOLUTION

For a variety of assemblies and performance parameters, the nuclear data sensitivity is tabulated as a function of nuclide, reaction type, and energy. Nuclear data induced uncertainties are quantified and results of integral experiments are incorporated in a consistent fashion resulting in improved uncertainty estimates of reactor performance for devices being designed. A first attempt is made in the quantitative specification of new cross section measurements required to satisfy specific design goals.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

The sample problem required various times to execute each step ranging from 10 seconds to 20 minutes on the IBM 360/91.

8. COMPUTER HARDWARE REQUIREMENTS

FORSS is operable on the IBM 360/370 series (A) or on a CDC computer (B). It uses a maximum of 23 tapes or direct access devices and requires 170 K to 560 K storage.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran H or Assembler compiler is required.

10. REFERENCES

C. R. Weisbin, J. H. Marable, J. L. Lucius, E. M. Oblow, F. R. Mynatt, R. W. Peelle, and F. G. Perey, "Application of FORSS Sensitivity and Uncertainty Methodology to Fast Reactor Benchmark Analysis," ORNL/TM-5563 (December 1976).

J. L. Lucius, C. R. Weisbin, J. H. Marable, J. D. Drischler, R. Q. Wright, and J. E. White, A "User's Manual for the FORSS Sensitivity and Uncertainty Analysis Code System," ORNL-5316 (January 1981).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and one (1.2MB) DOS diskette which contains the source codes and sample problem input and output.

12. DATE OF ABSTRACT

January 1982.