Influence of crack depth on the fracture toughness of reactor pressure vessel steel
The Heavy Section Steel Technology Program (HSST) at Oak Ridge National Laboratory (ORNL) is investigating the influence of flaw depth on the fracture toughness of reactor pressure vessel (RPV) steel. Recently, it has been shown that, in notched beam testing, shallow cracks tend to exhibit an elevated toughness as a result of a loss of constraint at the crack tip. The loss of constraint takes place when interaction occurs between the elastic-plastic crack-tip stress field and the specimen surface nearest the crack tip. An increased shallow-crack fracture toughness is of interest to the nuclear industry because probabilistic fracture-mechanics evaluations show that shallow flaws play a dominant role in the probability of vessel failure during postulated pressurized-thermal-shock (PTS) events. Tests have been performed on beam specimens loaded in 3-point bending using unirradiated reactor pressure vessel material (A533 B). Testing has been conducted using specimens with a constant beam depth (W = 94 mm) and within the lower transition region of the toughness curve for A533 B. Test results indicate a significantly higher fracture toughness associated with the shallow flaw specimens compared to the fracture toughness determined using deep-crack (a/W = 0.5) specimens. Test data also show little influence of thickness on the fracture toughness for the current test temperature ({minus}60{degree}C). 21 refs., 5 figs., 3 tabs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- NRC; Nuclear Regulatory Commission, Washington, DC (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5849477
- Report Number(s):
- CONF-9105188-1; ON: DE91012537
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
220200* -- Nuclear Reactor Technology-- Components & Accessories
36 MATERIALS SCIENCE
360103 -- Metals & Alloys-- Mechanical Properties
ALLOYS
CONTAINERS
CRACK PROPAGATION
CRACKS
DATA
DEFECTS
EXPERIMENTAL DATA
FRACTURE MECHANICS
FRACTURE PROPERTIES
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
LOW ALLOY STEELS
MATERIALS
MECHANICAL PROPERTIES
MECHANICS
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
NUMERICAL DATA
POWER PLANTS
PRESSURE VESSELS
REACTOR MATERIALS
STEEL-ASTM-A533
STEELS
THERMAL POWER PLANTS