NESC0889 RAS.
RAS, Fault Tree Analysis, Reliability, Minimal Cut Sets for Common Cause Failure
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 AUTHOR, MATERIAL, CATEGORIES
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| Program name | Package id | Status | Status date |
|---|---|---|---|
| RAS | NESC0889/02 | Tested | 01-JUN-1982 |
Machines used:
| Package ID | Orig. computer | Test computer |
|---|---|---|
| NESC0889/02 | CDC 7600 | CDC 7600 |
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3. DESCRIPTION OF PROBLEM OR FUNCTION
The Reliability Analysis Sys- tem, RAS, is an integrated package of computer programs for the quantification of fault trees. In particular, RAS has the capability of performing phased mission analysis. A phased mission is a task to be performed by a system during which the logic model and/or the component failure mode characteristics change at predetermined times. RAS is capable of finding minimal cut sets from fault trees and of calculating reliability characteristics for the basic events, the minimal cut sets, and the top event of a fault tree. In addi- tion, mission cut set cancellation and four methods of bounding mis- sion unreliability have been incorporated into RAS.
The Reliability Analysis Sys- tem, RAS, is an integrated package of computer programs for the quantification of fault trees. In particular, RAS has the capability of performing phased mission analysis. A phased mission is a task to be performed by a system during which the logic model and/or the component failure mode characteristics change at predetermined times. RAS is capable of finding minimal cut sets from fault trees and of calculating reliability characteristics for the basic events, the minimal cut sets, and the top event of a fault tree. In addi- tion, mission cut set cancellation and four methods of bounding mis- sion unreliability have been incorporated into RAS.
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4. METHOD OF SOLUTION
RAS is based upon the MPCUS, POCUS, KITT1, SRTPRN, and COMCAN programs. A new FATRAM algorithm for determining minimal cut sets is included in RAS. MOCUS is used to determine the minimal cut sets from a fault tree. POCUS and KITT1 are used to cal- culate reliability characteristics for the basic events, the cut sets, and the top event of a fault tree. SRTPRN sorts minimal cut sets into groups according to the importance of the cut sets. COMCAN is used, in common cause failure analysis, to search basic events in minimal cut sets for shared secondary failure event susceptibilities or common linking conditions among components.
RAS is based upon the MPCUS, POCUS, KITT1, SRTPRN, and COMCAN programs. A new FATRAM algorithm for determining minimal cut sets is included in RAS. MOCUS is used to determine the minimal cut sets from a fault tree. POCUS and KITT1 are used to cal- culate reliability characteristics for the basic events, the cut sets, and the top event of a fault tree. SRTPRN sorts minimal cut sets into groups according to the importance of the cut sets. COMCAN is used, in common cause failure analysis, to search basic events in minimal cut sets for shared secondary failure event susceptibilities or common linking conditions among components.
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10. REFERENCES
- Dale M. Rasmuson, Neldon H. Marshall, and Gary R. Burdick,
Users's Guide for the Reliability Analysis System (RAS),
TREE-1168, September 1977.
- RAS, NESC No. 889.C176, RAS Tape Description and Implementation
Information,
National Energy Software Center Note 81-62, June 8, 1981.
- J.B. Fussell, F.B. Henry, and N.H. Marshall,
MOCUS: A Computer Program to Obtain Minimal Sets from Fault Trees, ANCR-1156, August 1974.
- W.E. Vesley and R.E. Narum,
PREP and KITT: Computer Codes for the Automatic Evaluation of a
Fault Tree,
IN-1349, August 1970.
- C.A. Dolan,
SRTPRN: A Program to Sort and Prune Fault Tree Cut Sets,
TREE-1012, December 1976.
- G.R. Burdick, N.H. Marshall, and J.R. Wilson,
COMCAN: A Computer Program for Common Cause Analysis,
ANCR-1314, June 1976.
- Dale M. Rasmuson, Neldon H. Marshall, and Gary R. Burdick,
Users's Guide for the Reliability Analysis System (RAS),
TREE-1168, September 1977.
- RAS, NESC No. 889.C176, RAS Tape Description and Implementation
Information,
National Energy Software Center Note 81-62, June 8, 1981.
- J.B. Fussell, F.B. Henry, and N.H. Marshall,
MOCUS: A Computer Program to Obtain Minimal Sets from Fault Trees, ANCR-1156, August 1974.
- W.E. Vesley and R.E. Narum,
PREP and KITT: Computer Codes for the Automatic Evaluation of a
Fault Tree,
IN-1349, August 1970.
- C.A. Dolan,
SRTPRN: A Program to Sort and Prune Fault Tree Cut Sets,
TREE-1012, December 1976.
- G.R. Burdick, N.H. Marshall, and J.R. Wilson,
COMCAN: A Computer Program for Common Cause Analysis,
ANCR-1314, June 1976.
NESC0889/02, included references:
- Dale M. Rasmuson, Neldon H. Marshall, and Gary R. Burdick:Users's Guide for the Reliability Analysis System (RAS)
TREE-1168 (September 1977)
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11. MACHINE REQUIREMENTS
If the program is segmented, 42,000 (octal) words of small core memory (SCM) and 10 (octal) words of large core memory (LCM) are required for execution on a CDC7600. For the CDC 6600, 135,000 (octal) words of central memory and 10 (octal) words of Extended Core Storage (ECS) are required. Without segmentation, additional memory will be required.
If the program is segmented, 42,000 (octal) words of small core memory (SCM) and 10 (octal) words of large core memory (LCM) are required for execution on a CDC7600. For the CDC 6600, 135,000 (octal) words of central memory and 10 (octal) words of Extended Core Storage (ECS) are required. Without segmentation, additional memory will be required.
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NESC0889/02
| File name | File description | Records |
|---|---|---|
| NESC0889_02.002 | RAS INFORMATION | 39 |
| NESC0889_02.003 | RAS JCL FOR SAMPLE CASE | 25 |
| NESC0889_02.004 | RAS SOURCE (FORTRAN-4) | 11233 |
| NESC0889_02.005 | INEL ENV. ROUTINES FOR SCOPE 2.1 | 535 |
| NESC0889_02.006 | INEL ENV. ROUTINES FOR NOS/BE | 566 |
| NESC0889_02.007 | RAS INPUT FOR SAMPLE CASE | 91 |
| NESC0889_02.008 | COMCAN SUSCEPTIBILITY TABLES | 28 |
| NESC0889_02.009 | SEGLOAD DIRECTIVES | 16 |
| NESC0889_02.010 | RAS OUTPUT OF SAMPLE CASE | 802 |
Keywords: LMFBR reactors, failures, fault tree analysis, reliability, safety, system failure analysis.