New techniques for modeling the reliability of reactor pressure vessels
In recent years several probabilistic fracture mechanics codes, including the VISA code, have been developed to predict the reliability of reactor pressure vessels. This paper describes new modeling techniques used in a second generation of the VISA code entitled VISA-II. Results are presented that show the sensitivity of vessel reliability predictions to such factors as inservice inspection to detect flaws, random positioning of flaws within the vessel walls thickness, and fluence distributions that vary through-out the vessel. The algorithms used to implement these modeling techniques are also described. Other new options in VISA-II are also described in this paper. The effect of vessel cladding has been included in the heat transfer, stress, and fracture mechanics solutions in VISA-II. The algorithm for simulating flaws has been changed to consider an entire vessel rather than a single flaw in a single weld. The flaw distribution was changed to include the distribution of both flaw depth and length. A menu of several alternate equations has been included to predict the shift in RTNDT. For flaws that arrest and later re-initiate, an option was also included to allow correlating the current arrest thoughness with subsequent initiation toughnesses. 21 refs.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (USA)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 5594264
- Report Number(s):
- PNL-SA-13617; CONF-860722-16; ON: TI86013596
- Resource Relation:
- Conference: ASME pressure vessel and piping conference and exhibit, Chicago, IL, USA, 20 Jul 1986
- Country of Publication:
- United States
- Language:
- English
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VISA-II: a computer code for predicting the probability of reactor pressure vessel failure
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Related Subjects
36 MATERIALS SCIENCE
FRACTURE MECHANICS
V CODES
HEAT TRANSFER
PRESSURE VESSELS
IN-SERVICE INSPECTION
RELIABILITY
PWR TYPE REACTORS
STRESSES
ALGORITHMS
COMPUTERIZED SIMULATION
PROBABILISTIC ESTIMATION
COMPUTER CODES
CONTAINERS
ENERGY TRANSFER
INSPECTION
MATHEMATICAL LOGIC
MECHANICS
REACTORS
SIMULATION
WATER COOLED REACTORS
WATER MODERATED REACTORS
210200* - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
360103 - Metals & Alloys- Mechanical Properties
360104 - Metals & Alloys- Physical Properties