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NESC0704 COMCAN3/COMCAN.

COMCAN, Fault Tree Analysis, Minimal Cut Sets for Common Cause Failure

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1. NAME OR DESIGNATION OF PROGRAM:  COMCAN3/COMCAN.
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2. COMPUTERS
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Program name Package id Status Status date
COMCAN-3 NESC0704/04 Tested 20-JAN-1986

Machines used:

Package ID Orig. computer Test computer
NESC0704/04 CDC CYBER 176 CDC CYBER 740
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3. DESCRIPTION OF PROBLEM OR FUNCTION

The COMCAN fault tree analysis  codes are designed to analyze complex systems, such as nuclear plants for common causes of failure. A common cause event, or common mode failure, is a secondary cause that could contribute to the failure of more than one component and violates the assumption of independence. Analysis of such events is an integral part of system  reliability and safety analysis. A significant common cause event is a secondary cause common to all basic events in one or more minimal  cut sets. Minimal cut sets containing events from components sharing a common location or a common link are called common cause candidates. Components share a common location if no barrier insulates any one of them from the secondary cause. A common link is a dependency among components which cannot be removed by a physical  barrier (e.g., a common energy source or common maintenance instructions).
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4. METHOD OF SOLUTION

The COMCAN programs search the fault tree minimal cut sets for shared susceptibility to various secondary events (common causes) and common links between components. In the case of common causes, a location check may also be performed to determine whether barriers to the common cause exist between components. The programs can locate common manufacturers of components having events in the same minimal cut set. A relative rankling scheme for secondary event susceptibility is included in the programs.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

COMCAN is limited to the analysis of fault tree minimal cut sets produced by other programs while COMCAN3 is an independent program, utilizing the fault tree code FATRAM, which is incorporated as a program module, for a thorough analysis of the fault tree for sources of common cause failures.
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6. TYPICAL RUNNING TIME

Less than 2 seconds is required to execute either the COMCAN sample problem on an IBM370/195 or COMCAN3 problem on the CDC CYBER176.
NESC0704/04
NEA-DB ran the test cases included in this package on a CDC CYBER 740 computer. Required CPU times were 17 seconds for test  case 1, and 7.5 seconds for test case 2.
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS

The format used for COMCAN is compatible with the input format of programs for qualitative and quantitative reliability and safety analyses, such as MOCUS (NESC Abstract 653) and PREP,KITT (NESC Abstract 528). The cut set input deck can be punched by MOCUS. COMCAN3 is based on the earlier EG&G Idaho fault tree analysis codes - COMCAN, RAS (NESC Abstract 889), COMCAN2, and COMCAN2A.
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9. STATUS
Package ID Status date Status
NESC0704/04 20-JAN-1986 Tested at NEADB
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10. REFERENCES

- Gary R. Burdick, Neldon H. Marshall, James R. Wilson,
  COMCAN: A Computer Program for Common Cause Analysis,
  ANCR-1314, May 1976.
- J.B. Fussell, G.R. Burdick, D.M. Rasmuson, J.R. Wilson, J.C.
  Zipperer,
  A Collection of Methods for Reliability and Safety Engineering,
  ANCR-1273, April 1976.
- W.E. Vesely and R.E. Narum,
  PREP and KITT: Computer Codes for the Automatic Evaluation of
                Fault Tree,
  IN-1349, August 1970.
- J.B. Russell, E.B. Henry, N.H. Marshall,
MOCUS: A Computer Program to Obtain Minimal Sets from Fault Trees,    ANCR-1156, August 1974.
- D.M. Rasmuson and N.H. Marshall,
  FATRAM: A Core Efficient Cut-Set Algorithm,
  IEEE Transtactions on Reliability, Vol. R-27, No. 4, pp. 250-253
  October 1978.
NESC0704/04, included references:
- D.M Rasmuson, J.C Shepherd, N.H Marshall and L.R Fitch:
  Use of COMCAN III in System Design and Reliability Analysis.
  EGG-2187 (March 1982).
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11. MACHINE REQUIREMENTS

136K octal words of memory for COMCAN3 and 140K bytes of memory for COMCAN.
NESC0704/04
To run the test cases on a CDC CYBER 740, main storage  requirements are 163,000 (octal) words for case 1, and 165,100 (octal) words for case 2.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC0704/04 FORTRAN-77
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

NOS/BE 1.4 (CDC CYBER176), NOS 1.4 (CDC CYBER175, and OS/360 (IBM360).
NESC0704/04
NOS 1.4 + 531 (CDC CYBER 740)
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

The
four Assembly language routines included in the IBM360 COMCAN package are the FORTRAN input-output and abnormal termination dump routines: FABEND, FIOCS, IBCOM# and INFILQ. These are a part of the  NRTS Environmental Routines package (NESC Abstract 613).
COMCAN3 uses CMM (Common Memory Manager) to allocate main memory, but can be modified to eliminate use of CMM.
COMCAN3 uses GETPARM, the CDC FTN5 library routine, to pass parameters to the program during execution.
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15. NAME AND ESTABLISHMENT OF AUTHOR

    COMCAN      G.R. Burdick, N.H. Marshall and J.R. Wilson

    COMCAN3     D.M. Rasmuson, J.C. Shepherd, N.H. Marshall
                and L.R. Fitch
                EG&G Idaho, Inc.
                P.O. Box 1625
                Idaho Falls, Idaho 83401
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16. MATERIAL AVAILABLE
NESC0704/04
File name File description Records
NESC0704_04.003 INFORMATION FILE 70
NESC0704_04.004 JCL 13
NESC0704_04.005 COMCAN3 FORTRAN UPDATE SOURCE 11316
NESC0704_04.006 UPDATE DIRECTIVES 3
NESC0704_04.007 SAMPLE PROBLEM 1 INPUT 47
NESC0704_04.008 SAMPLE PROBLEM 2 INPUT 34
NESC0704_04.009 PRINTED OUTPUT OF BOTH SAMPLE PROBLEMS 1709
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17. CATEGORIES
  • G. Radiological Safety, Hazard and Accident Analysis
  • P. General Mathematical and Computing System Routines

Keywords: fault tree analysis, reliability, system failure analysis.