RSICC CODE PACKAGE PSR-392
1. NAME AND TITLE
OCA-P: Pressure Vessel Fracture-Mechanics Code System.
2. CONTRIBUTOR
Oak Ridge National Laboratory, Oak Ridge, Tennessee.
3. CODING LANGUAGE AND COMPUTER
Ryan-McFarland Professional FORTRAN; IBM PC (P00392IBMPC00).
FORTRAN; IBM-3033 (P00392I303300).
4. NATURE OF PROBLEM SOLVED
OCA-P is a probabilistic fracture-mechanics code prepared specifically for evaluating the integrity of pressurized-water reactor vessels subjected to overcooling-accident loading conditions. Based on linear-elastic fracture mechanics, it has two and limited three-dimensional flaw capability, and can treat cladding as a discrete region. Both deterministic and probabilistic analyses can be performed. For deterministic analysis, it is possible to conduct a search for critical values of the fluence and the nil-ductility reference temperature corresponding to incipient initiation of the initial flaw. The probabilistic portion of OCA-P is based on Monte Carlo techniques, and simulated parameters include fluence, flaw depth, fracture toughness, nil-ductility reference temperature, and concentrations of copper, nickel, and phosphorous. Plotting capabilities include the construction of critical-crack-depth diagrams (deterministic analysis) and a variety of histograms (probabilistic analysis).
5. METHOD OF SOLUTION
OCA-P accepts as input the reactor primary-system pressure and the reactor pressure-vessel downcomer coolant temperature, as functions of time in the specified transient. Then, the wall temperatures and stresses are calculated as a function of time and radial position in the wall, and the fracture-mechanics analysis is performed to obtain the stress intensity factors as a function of crack depth and time in the transient. In a deterministic analysis, values of the static crack initiation toughness and the crack arrest toughness are also calculated for all crack depths and times in the transient. A comparison of these values permits an evaluation of flaw behavior. For a probabilistic analysis, OCA-P generates a large number of reactor pressure vessels, each with a different combination of the various values of the parameters involved in the analysis of flaw behavior. For each of these vessels, a deterministic fracture-mechanics analysis is performed to determine whether vessel failure takes place. The conditional probability of failure is simply the number of vessels that fail divided by the number of vessels generated.
6. RESTRICTIONS OR LIMITATIONS
None.
7. TYPICAL RUNNING TIME
The sample problem which analyzes one weld using 10,000 trials takes 8 seconds on an Pentium II (266 MHz) PC with a hard disk.
8. COMPUTER HARDWARE REQUIREMENTS
The PC version requires 512 Kbytes of memory.
9. COMPUTER SOFTWARE REQUIREMENTS
The enclosed PC executables were compiled with PROFORT (Professional FORTRAN, Version 1.0, IBM (R) Personal Computer software by Ryan-McFarland Corp., First Edition, November 1984. There were run in a DOS window of Windows95 on a Pentium II. A Fortran compiler and an assembler are required for the IBM 3033 version.
10. REFERENCES
a) Included in the document:
R. D. Cheverton and D. G. Ball, "OCA-P, A Deterministic and Probabilistic Fracture-Mechanics Code for Application to Pressure Vessels," NUREG/CR-3618 (ORNL-5991) (May 1984).
D. G. Ball and R. D. Cheverton, "Adaptation of OCA-P, A Probabilistic Fracture-Mechanics Code, to a Personal Computer," NUREG/CR-4468 (ORNL/CSD/TM-233) (December 1985).
P. Johnson, "OCA-P, NESC No. 1125.3033, OCA-P IBM3033 Version Tape Description and Implementation Information," NESC 90-87 (April 18, 1990).
P. Johnson, "OCA-P, NESC No. 1125.PC, OCA-P IBM PC Version Flexible Disk Cartridge Descriptions," NESC Note 90-87 (April 18, 1990).
b) Background Information:
D. G. Ball, R. D. Cheverton, J. B. Drake, and S. K. Iskander, "OCA-II, A Code for Calculating the Behavior of 2-D and 3-D Surface Flows in a Pressure Vessel Subjected to Temperature and Pressure Transients," NUREG/CR-3491 (ORNL-5934) (February 1984).
11. CONTENTS OF CODE PACKAGE
Included are the referenced documents in (10.a) and a 3.5" DOS diskette with compressed DOS PkWare (R) file which contains source, executables, sample data for input and output, and data libraries.
12. DATE OF ABSTRACT
May 1999.
KEYWORD: FRACTURE MECHANICS