**RSICC CODE PACKAGE PSR-380**

**1. NAME AND TITLE**

SETS: Set Equation Transformation System.

**2. CONTRIBUTORS**

Sandia National Laboratories, Albuquerque, New Mexico, through the Energy Science and Technology Software Center, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

Fortran Extended Version 4; CDC CYBER180 (P00380/CDCMF/00).

**4. NATURE OF PROBLEM SOLVED**

SETS is used for symbolic manipulation of Boolean equations, particularly the reduction of equations by the application of Boolean identities. It is a flexible and efficient tool for performing probabilistic risk analysis (PRA), vital area analysis, and common cause analysis. The equation manipulation capabilities of SETS can also be used to analyze noncoherent fault trees and determine prime implicants of Boolean functions, to verify circuit design implementation, to determine minimum cost fire protection requirements for nuclear reactor plants, to obtain solutions to combinatorial optimization problems with Boolean constraints, and to determine the susceptibility of a facility to unauthorized access through nullification of sensors in its protection system.

Two auxiliary programs, SEP and FTD, are included. SEP performs the quantitative analysis of reduced Boolean equations (minimal cut sets) produced by SETS. The user can manipulate and evaluate the equations to find the probability of occurrence of any desired event and to produce an importance ranking of the terms and events in an equation. FTD is a fault tree drawing program which uses the proprietary ISSCO DISSPLA graphics software to produce an annotated drawing of a fault tree processed by SETS. The DISSPLA routines are not included.

**5. METHOD OF SOLUTION**

The SETS program is used to read, interpret, and execute the statements of a SETS user program which is an algorithm that specifies the particular manipulations to be performed and the order in which they are to occur.

**6. RESTRICTIONS OR LIMITATIONS**

Any properly formed set equation involving the set operations of union, intersection, and complement is acceptable for processing by the SETS program. Restrictions on the size of a set equation that can be processed are not absolute but rather are related to the number of terms in the disjunctive normal form of the equation, the number of literals in the equation, etc. Nevertheless, set equations involving thousands and even hundreds of thousands of terms can be processed successfully.

**7. TYPICAL RUNNING TIME**

Running time varies with respect to the particular equations being processed and the symbolic manipulations being performed. NESC executed the SETS sample problem in 20 CP seconds on a CDC CYBER 175.

**8. COMPUTER HARDWARE REQUIREMENTS**

SETS ran on CDC Cyber computers.

**9. COMPUTER SOFTWARE REQUIREMENTS**

SETS was developed on a CDC Cyber running NOS 2.3 with the FTN 4.8+528 compiler. A Fortran compiler is required to install the code. Modifications will certainly be necessary to run on other computers. This release was first distributed by NESC in December 1974. It was not tested or modified when it was released by RSICC in March 2002. The files in this package were obtained through the NEA Data Bank (identifier NESC06023/02).

**10. REFERENCES**

** a: Included in document:**

R.B. Worrell, "SETS Reference Manual," NUREG/CR-4213 (SAND83-2675) (May 1985).

M.D. Olman, "Quantitative Fault Tree Analysis Using the Set Evaluation Program (SEP)," NUREG/CR-1935 (SAND80-2712) (September 1982).

A. W. Shiver, "Notes on Using the Fault Tree Drawing Program," Sandia National Laboratories Memorandum (June 25, 1981).

D.A. Oliver, "Fault Tree Drawing Program Users Instructions," SLA-73-0409 (April 1973).

** b: Background information:**

D. W. Stack, "A SETS User's Manual for Accident Sequence Analysis," NUREG/CR-3547 (SAND83-2238) (January 1984).

D. W. Stack and K. A. Francis, "Vital Area Analysis Using SETS," NUREG/CR-1487 (SAND80-1095) (May 1980).

D. W. Stack and M. S. Hill, "A SETS User's Manual for Vital Area Analysis," NUREG/CR-3134 (SAND83-0074) (April 1984).

G.B. Varnado, W.H. Horton, and P.R. Lobner, "Modular Fault Tree Analysis Procedures Guide, Volume 1 Main Report," NUREG/CR-3268/1 (SAND83-0963/1) (August 1983).

G.B. Varnado, W.H. Horton, and P.R. Lobner, "Modular Fault Tree Analysis Procedures Guide, Volume 2 Appendices A, B, and C," NUREG/CR-3268/2 (SAND83-0963/2) (August 1983).

G.B. Varnado, W.H. Horton, and P.R. Lobner, "Modular Fault Tree Analysis Procedures Guide, Volume 3 Appendices D, E, F, G, and H," NUREG/CR-3268/3 (SAND83-0963/3) (August 1983).

G.B. Varnado, W.H. Horton, and P.R. Lobner, "Modular Fault Tree Analysis Procedures Guide, Volume 4 Appendix I," NUREG/CR-3268/4 (SAND83-0963/4) (August 1983).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents in 10.a and a CD with a GNU compressed tar file which includes the SETS source, JCL, data and test case input and output.

**12. DATE OF ABSTRACT**

March 2002.

** KEYWORDS:** REACTOR SAFETY; RISK ASSESSMENT