Computer Programs

NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROBLEM OR FUNCTION, METHOD OF SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, UNUSUAL FEATURES OF THE PROGRAM, RELATED AND AUXILIARY PROGRAMS, STATUS, REFERENCES, MACHINE REQUIREMENTS, LANGUAGE, OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED, OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHORS, MATERIAL, CATEGORIES

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Program name | Package id | Status | Status date |
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FRANTIC-3 | NESC0766/02 | Tested | 02-MAR-1988 |

Machines used:

Package ID | Orig. computer | Test computer |
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NESC0766/02 | CDC 7600 | CDC CYBER 740 |

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3. DESCRIPTION OF PROBLEM OR FUNCTION

FRANTIC3 was developed to evaluate system unreliability using time-dependent techniques. The code provides two major options: to evaluate standby system unavailability or, in addition to the unavailability, to calculate the total system failure probability by including both the unavailability of the system on demand as well as the probability that it will operate for an arbitrary time period following the demand. The FRANTIC time-dependent reliability models provide a large selection of repair and testing policies applicable to standy or continuously operating systems consisting of periodically tested, monitored, and non-repairable (non-testable) components. Time- dependent and test frequency dependent failures, as well as demand stress related failure, test-caused degradation and wear-out, test associated human errors, test deficiencies, test override, unscheduled and scheduled maintenance, component renewal and replacement policies, and test strategies can be prescribed.

The conditional system unvailabilities associated with the downtimes of the user specified failed component are also evaluated. Optionally, the code can perform a sensitivity study for system unavailability or total failure probability to the failure characteristics of the standby components.

FRANTIC3 was developed to evaluate system unreliability using time-dependent techniques. The code provides two major options: to evaluate standby system unavailability or, in addition to the unavailability, to calculate the total system failure probability by including both the unavailability of the system on demand as well as the probability that it will operate for an arbitrary time period following the demand. The FRANTIC time-dependent reliability models provide a large selection of repair and testing policies applicable to standy or continuously operating systems consisting of periodically tested, monitored, and non-repairable (non-testable) components. Time- dependent and test frequency dependent failures, as well as demand stress related failure, test-caused degradation and wear-out, test associated human errors, test deficiencies, test override, unscheduled and scheduled maintenance, component renewal and replacement policies, and test strategies can be prescribed.

The conditional system unvailabilities associated with the downtimes of the user specified failed component are also evaluated. Optionally, the code can perform a sensitivity study for system unavailability or total failure probability to the failure characteristics of the standby components.

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4. METHOD OF SOLUTION

FRANTIC3 uses a set of analytical equations for component unavailabilities and failure intensities with exponential and Weibull time distributions for constant test and duration times. The FRANTIC code determines the state (test, repair, or between test) of each component at each time point and selects the appropriate component unavailability model depending on the state. Using the appropriate logical relationships among the unavailabilities of individual components, the system unavailability (or total failure probability) is also calculated at these time points. Then, the system average unavailability (or total failure probability) is calculated by integrating the instantaneous unavailability (or total failure probability) over the standby time period. A Boolean equation is specified by the user via the SYSCOM subroutine to define the system unavailability functions. The system failure occurrence rate functions needed for the system unreliability evaluation is user defined via the SYSOP subroutine.

FRANTIC3 uses a set of analytical equations for component unavailabilities and failure intensities with exponential and Weibull time distributions for constant test and duration times. The FRANTIC code determines the state (test, repair, or between test) of each component at each time point and selects the appropriate component unavailability model depending on the state. Using the appropriate logical relationships among the unavailabilities of individual components, the system unavailability (or total failure probability) is also calculated at these time points. Then, the system average unavailability (or total failure probability) is calculated by integrating the instantaneous unavailability (or total failure probability) over the standby time period. A Boolean equation is specified by the user via the SYSCOM subroutine to define the system unavailability functions. The system failure occurrence rate functions needed for the system unreliability evaluation is user defined via the SYSOP subroutine.

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6. TYPICAL RUNNING TIME

Execution time is a function of the number of time points generated by the code based on component input. The more nonlinear the system standby unavailability or the system failure occurence rate, the more time points are required. The execution time increases nearly linearly with this number. NESC executed the sample problem in 55 seconds on a CDC CYBER875.

Execution time is a function of the number of time points generated by the code based on component input. The more nonlinear the system standby unavailability or the system failure occurence rate, the more time points are required. The execution time increases nearly linearly with this number. NESC executed the sample problem in 55 seconds on a CDC CYBER875.

NESC0766/02

The test case included in this package has been executed at NEA-DB on a CDC CYBER computer in 219 seconds of CPU time.[ top ]

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8. RELATED AND AUXILIARY PROGRAMS

The first version of FRANTIC was useful only in modeling a period of normal operation when the component is experiencing a relatively constant hazard rate due primarily to random failure. FRANTIC2 incorporated the Weibull distribution allowing it to model burn-in or wear-out phenomena as well as normal operation. FRANTIC3 capability is enhanced further to evaluate standby system unavailability or, in addition to the unavailability, to calculate the total system failure probability or unreliability.

The first version of FRANTIC was useful only in modeling a period of normal operation when the component is experiencing a relatively constant hazard rate due primarily to random failure. FRANTIC2 incorporated the Weibull distribution allowing it to model burn-in or wear-out phenomena as well as normal operation. FRANTIC3 capability is enhanced further to evaluate standby system unavailability or, in addition to the unavailability, to calculate the total system failure probability or unreliability.

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10. REFERENCES

- W.E. Veseley, F.F. Goldberg, J.T. Powers, J.M. Dickey, J.M. Smith, and R.E. Hall,

FRANTIC II - A Computer Code for Time Dependent Unavailability

Analysis,

NUREG/CR-1924 (BNL-NUREG-51355), APRIL 1981.

- W.E. Veseley, F.F. Goldberg, J.T. Powers, J.M. Dickey, J.M. Smith, and R.E. Hall,

FRANTIC II - A Computer Code for Time Dependent Unavailability

Analysis,

NUREG/CR-1924 (BNL-NUREG-51355), APRIL 1981.

NESC0766/02, included references:

- T. Ginzburg and J.T. Powers:FRANTIC-III - A Computer Code for Time-Dependent Reliability

Analysis (Methodology Manual)

A-3230 (April 1, 1984)

- T. Ginzburg and J.T. Powers:

FRANTIC-III - A Computer Code for Time-Dependent Reliability

Analysis (User's Manual)

A-3230 (August 20, 1986)

- P. Johnson:

FRANTIC3 Tape Description and Implementation Information

NESC Note 87-89 (August 31, 1987)

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NESC0766/02

To execute the test case included in this package on a CDC CYBER 740 computer, 170,000 (octal) words of CM and 65,000 (octal) words of ECS were required.[ top ]

NESC0766/02

NOS2.5.1 (CDC CYBER 740).[ top ]

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NESC0766/02

File name | File description | Records |
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NESC0766_02.001 | Information file | 56 |

NESC0766_02.002 | JCL | 16 |

NESC0766_02.003 | FRANTIC3 FORTRAN source | 3410 |

NESC0766_02.004 | Sample problem user-supp. subroutines | 14 |

NESC0766_02.005 | Sample problem input | 39 |

NESC0766_02.006 | Sample problem output | 763 |

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- G. Radiological Safety, Hazard and Accident Analysis
- P. General Mathematical and Computing System Routines

Keywords: availability, engineered safety systems, reliability, systems analysis, testing, time dependence.