NESC1146 DORIAN.

1. NAME OR DESIGNATION OF PROGRAM:  DORIAN, Bayes method plant aging
risk analysis

3. DESCRIPTION OF PROGRAM OR FUNCTION

DORIAN is an integrated package for performing Bayesian aging analysis of reliability data; e.g. for identifying trends in component failure rates and/or outage durations as a function of time. The user must specify several alternative hypothesized "aging models" (i.e., possible trends) along prior probabilities indicating the subject probability that each trend is actually the correct one. DORIAN then uses component failure and/or repair data over time to update these prior probabilities and develop a posterior probability for each aging model, representing the probability that each model is the correct one in light of the observed data rather than a priori. Mean, median, and 5th and 95th percentile trends are also compiled from the posterior probabilities.

4. METHOD OF SOLUTION

DORIAN carries out a Bayesian analysis of failure data and a prior distribution on a time-dependent failure rate to obtain a posterior distribution on the failure rate. The form of the time-dependent failure rate is arbitrary, because DORIAN approximates the form by a step-function, constant within specified  time intervals. Similarly, the parameters may have any prior distribution, because DORIAN uses a discrete distribution to approximate this. Likewise, the database file produced by DORIAN approximates the entire range of possible failure rates or outage durations developed by means of a discrete probability distribution  containing no more than 20 distinct values with their probabilities.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Prior distribution is discrete with up to 25 values. Up to 60 times are accommodated in the discrete time history.

6. TYPICAL RUNNING TIME:

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

DORIAN is compatible with the RISKMAN system for risk analysis, Pickard, Lowe and Garrick, Inc. proprietary workstation software. The MicroEMACS 3.8 editor is provided as part of the DORIAN software package.

10. REFERENCES

- DORIAN, NESC No. 1146, DORIAN Flexible Disk Cartridge Description,   National Software Center Note 92-07, October 8, 1991.
- Charles Petzold, "Just Looking, Thank you", PC Magazine, March
  25, 1986.

- Vicki M. Bier and al:
  Development and Demonstration of Methods for Nuclear Power Plant
  Aging Risk Analysis: Dorian Users Manual,
  EGG-SSRE-8991 (April 1990).

11. MACHINE REQUIREMENTS

DORIAN requires an IBM PC or compatible computer with 640 Kbytes of memory, a fixed disk, one 3.5-inch 720 Kbyte flexible disk drive, a colour monitor (CGA, EGA, or VGA), and  math coprocessor.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  MS-DOS 3.3 or higher.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:  The
source is not supplied as part of this package.

15. NAME AND ESTABLISHMENT OF AUTHORS: , C.L. Atwood, EG&G Idaho, Inc.

test-case data   mag tapeDORGEN.BAT Batch File                      DATTP
test-case data   mag tapeDORGRF.BAT Batch File                      DATTP
test-case data   mag tapeDORIAN.BAT Batch File                      DATTP
load module      mag tapeDORI.EXE Executable File                   LODTP
load module      mag tapeDORIA.EXE Executable File                  LODTP
load module      mag tapeDORWIN.EXE Executable File                 LODTP
load module      mag tapeEMACS.EXE Executable File                  LODTP
test-case data   mag tapeDEFIII.GRD Auxiliary Information           DATTP
test-case data   mag tapeDORIN.GRD Auxiliary Information            DATTP
test-case data   mag tapeEMACS.HLP Auxiliary Information            DATTP
test-case data   mag tapeDEFIII.INP Sample Problem Input            DATTP
test-case data   mag tapeDUPIII.INP Sample Problem Input            DATTP
test-case data   mag tapeEXPIII.INP Sample Problem Input            DATTP
test-case data   mag tapeLINIII.INP Sample Problem Input            DATTP
test-case data   mag tapePERIII.INP Sample Problem Input            DATTP
test-case output mag tapeDEFIII.LST Sample Problem Output           OUTTP
test-case data   mag tapeDORIAN.MOD Auxiliary Information           DATTP
test-case data   mag tapeEMACS.RC Auxiliary Information             DATTP
test-case data   mag tapeDORIN.TMP Auxiliary Information           DATTP
test-case data   mag tapeBROWSE.COM Command File                    DATTP
test-case data   mag tapeBROWSE.DOC Documentation File              DATTP
report                   EGG-SSRE-8991 (April 1990)                 REPPT