Preliminary assessment of the fracture behavior of weld material in full-thickness clad beams
- Oak Ridge National Lab., TN (United States)
This report describes a testing program that utilizes full-thickness clad beam specimens to quantify fracture toughness for shallow cracks in material for which metallurgical conditions are prototypic of those found in reactor pressure vessels (RPVs). The beam specimens are fabricated from a section of an RPV wall (removed from a canceled nuclear plant) that includes weld, plate, and clad material. Metallurgical factors potentially influencing fracture toughness for shallow cracks in the beam specimens include material gradients due to welding and cladding applications, as well as material inhomogeneities in welded regions due to reheating in multiple weld passes. A summary of the testing program includes a description of the specimen geometry, material properties, the testing procedure, and the experimental results form three specimens. The yield strength of the weld material was determined to be 36% higher than the yield strength of the base material. An irradiation-induced increase in yield strength of the weld material could result in a yield stress that exceeds the upper limit where code curves are valid. The high yield strength for prototypic weld material may have implications for RPV structural integrity assessments. Analyses of the test data are discussed, including comparisons of measured displacements with finite-element analysis results, applications of toughness estimation techniques, and interpretations of constraint conditions implied by stress-based constraint methodologies. Metallurgical conditions in the region of the cladding heat-affected zone are proposed as a possible explanation for the lower-bound fracture toughness measured with one of the shallow-crack clad beam specimens. Fracture toughness data from the three clad beam specimens are compared with other shallow- and deep-crack uniaxial beam and cruciform data generated previously from A 533 Grade B plate material.
- Research Organization:
- US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10189507
- Report Number(s):
- NUREG/CR-6228; ORNL/TM-12735; ON: TI95001501; TRN: 94:021186
- Resource Relation:
- Other Information: PBD: Oct 1994
- Country of Publication:
- United States
- Language:
- English
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42 ENGINEERING
PRESSURE VESSELS
WELDED JOINTS
NUCLEAR POWER PLANTS
FRACTURE PROPERTIES
REACTOR MATERIALS
MATERIALS TESTING
EXPERIMENTAL DATA
RELIABILITY
DATA ANALYSIS
HEAT AFFECTED ZONE
THERMAL STRESSES
THERMAL SHOCK
FRACTURE MECHANICS
STEEL-ASTM-A533
STAINLESS STEELS
CLADDING
COMPOSITE MATERIALS
220200
420500
COMPONENTS AND ACCESSORIES