1. NAME AND TITLE

SENSIT: One-Dimensional, Multigroup Cross Section and Design Sensitivity and Uncertainty Analysis Code System Generalized Perturbation Theory.

2. CONTRIBUTOR

Los Alamos National Laboratory, Los Alamos, New Mexico.

3. CODING LANGUAGE AND COMPUTER

Fortran, Assembler language; CDC 7600.

4. NATURE OF PROBLEM SOLVED

SENSIT computes the sensitivity and uncertainty of a calculated integral response (such as a dose rate) due to input cross sections and their uncertainties. Sensitivity profiles are computed for neutron and gamma-ray reaction cross sections (of standard multigroup cross-section sets) and for secondary energy distributions (SED's) of multigroup scattering matrices.

5. METHOD OF SOLUTION

In the design sensitivity mode, SENSIT computes changes in an integral response due to design changes and gives the appropriate sensitivity coefficients. Cross-section uncertainty analyses are performed for three types of input data uncertainties: (a) cross-section covariance matrices for pairs of multigroup reaction cross sections, (b) spectral shape uncertainty parameters for secondary energy distributions (integral SED uncertainties), and (c) covariance matrices for energy-dependent response functions. For all three types of data uncertainties, SENSIT computes the resulting variance and expected standard deviation in an integral response of interest, based on generalized perturbation theory. SENSIT uses angular-flux files from one-dimensional discrete-ordinates code systems such as ONETRAN, ANISN, and DTF and reads multigroup cross-section sets in three different formats.

6. RESTRICTIONS OR LIMITATIONS

None noted.

7. TYPICAL RUNNING TIME

On the CDC 7600, sample problems 1 through 6 (each) ran in under 1 second, sample problem 7 required 12.9 seconds CPU time, and sample problem 8 executed in 62 seconds CPU time.

8. COMPUTER HARDWARE REQUIREMENTS

SENSIT is operable on the CDC 7600 computer.

9. COMPUTER SOFTWARE REQUIREMENTS

A Fortran compiler is required.

10. REFERENCE

S. A. W. Gerstl, "SENSIT: A Cross-Section and Design Sensitivity and Uncertainty Analysis Code," LA-8498-MS (August 1980).

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one (1.2MB) DOS diskette which contains the source code and input and output from the sample problems.

12. DATE OF ABSTRACT

February 1982; revised February 1983.