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NESC1084 TEMAC.

TEMAC, Top Event Sensitivity Analysis

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1. NAME OR DESIGNATION OF PROGRAM:  TEMAC.
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2. COMPUTERS
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Program name Package id Status Status date
TEMAC NESC1084/01 Tested 26-OCT-1988

Machines used:

Package ID Orig. computer Test computer
NESC1084/01 DEC VAX 8650 DEC VAX 8810
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3. DESCRIPTION OF PROGRAM OR FUNCTION

TEMAC is designed to permit the user to easily estimate risk and to perform sensitivity and uncertainty analyses with a Boolean expression such as produced by the SETS computer program. SETS produces a mathematical representation of a fault tree used to model system unavailability.  In the terminology of the TEMAC program, such a mathematical representation is referred to as a top event. The analysis of risk involves the estimation of the magnitude of risk, the sensitivity of risk estimates to base event probabilities and initiating event frequencies, and the quantification of the uncertainty in the risk estimates.
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4. METHOD OF SOLUTION

Sentivity and uncertainty analyses associated with top events involve mathematical operations on the corresponding Boolean expression for the top event, as well as repeated evaluations of the top event in a Monte Carlo fashion. TEMAC employs a general matrix approach which provides a convenient general form for Boolean expressions, is computationally efficient, and allows large problems to be analyzed.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of -
   4000 cut sets
    500 events
    500 values in a Monte Carlo sample
     16 characters in an event name
These restrictions are implemented through the FORTRAN 77 PARAMATER statement.
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6. TYPICAL RUNNING TIME

NESC executed each of the sample problem in less than 5 CPU seconds on a DEC VAX11/785.
NESC1084/01
The two test cases included in this package were run at NEA-DB on a VAX 8810 computer in 2.6 seconds of CPU time.
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS

SETS (NESC 623) is used for symbolic manipulation of Boolean equations, particularly the reduction of equations by the application of Boolean identities. LHS (NESC 1085), the Latin Hypercube Sampling program, generates multivariate samples either completely at random or by constrained randomization.
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9. STATUS
Package ID Status date Status
NESC1084/01 26-OCT-1988 Tested at NEADB
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10. REFERENCES

- Ronald L. Iman and Michael J. Shortencarier
  A FORTRAN 77 Program and User's Guide for the Generation of Latin
  Hypercube and Random Samples for Use With Computer Models,
  NUREG/CR-3624 (SAND83-2365), March 1984.
- R.B. Worrell
  SETS Reference Manual
  NUREG/CR-4213 (SAND83-2675), May 1985.
NESC1084/01, included references:
- R.L. Iman and M.J. Shortencarier :
  A User's Guide for the Top Event Matrix Analysis Code (TEMAC)
  NUREG/CR-4598 SAND86-0960 (August 1986)
- L. Eyberger :
  TEMAC Tape Description and Implementation Information
  NESC Note 87-99 (september 21, 1987)
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11. MACHINE REQUIREMENTS:  3.6 Mbytes of virtual memory are required for execution.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC1084/01 FORTRAN-77
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  VMS 4.3, 4.5.
NESC1084/01
VAX/VMS V5.0-1 with compiler FORTRAN V5.0-1.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHORS

           R.L. Iman and M.J. Shortencarier
           Sandia National Laboratories, ALbuquerque
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16. MATERIAL AVAILABLE
NESC1084/01
File name File description Records
NESC1084_01.001 Information file 79
NESC1084_01.002 TEMAC FORTRAN source 5426
NESC1084_01.003 Sample problem 1 (Input file 1) 9
NESC1084_01.004 Sample problem 1 (Input file 2) 4
NESC1084_01.005 Sample problem 1 (Input file 3) 7
NESC1084_01.006 Sample problem 1 (Input file 4) 8
NESC1084_01.007 Sample problem 1 (Input file 5) 50
NESC1084_01.008 Sample input to LHS program/to create file 7 18
NESC1084_01.009 Sample problem 2 (Input file 1) 10
NESC1084_01.010 Sample problem 2 (Input file 2) 37
NESC1084_01.011 Sample problem 2 (Input file 3) 16
NESC1084_01.012 Sample problem 2 (Input file 4) 17
NESC1084_01.013 Sample problem 2 (Input file 5) 150
NESC1084_01.014 Sample input to LHS program/to create file13 29
NESC1084_01.015 Output file of Sample problem 1 369
NESC1084_01.016 Output file of Sample problem 2 576
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17. CATEGORIES
  • P. General Mathematical and Computing System Routines

Keywords: Monte Carlo method, correlations, fault tree analysis, matrices, probabilistic sys assessment, risk assessment, sensitivity analysis.