학술논문

Crack-Arrest Testing of Irradiated Nuclear Reactor Pressure Vessel Steels at the Oak Ridge National Laboratory
Document Type
journal paper
Source
Journal of Testing and Evaluation, Nov 1998, Vol. 26, No. 6, pp. 546-554.
Subject
crack-arrest toughness
shift of toughness curve
American Society of Mechanical Engineers (ASME) KIR curve
ASME KIa curve
pressure vessel steels
reference temperature
RTNDT
effect of neutron irradiation on crack-arrest toughness
Language
English
ISSN
0090-3973
Abstract
Crack-arrest testing of nuclear pressure vessel steels has been conducted at Oak Ridge National Laboratory for many years. Four methods have been used to initiate fast-running cracks in crackarrest specimens: (1) the deposition of a brittle weld bead using hardfacing weld electrodes, (2) water quenching a chevron crack tip, (3) quenching the crack tip by discharging a large current into the crack tip region, and (4) the use of duplex specimens. A problem often encountered with Methods 1 and 4 is the control of the width of the heat-affected zone (HAZ). The HAZ is generally tough and can arrest crack propagation before it has run into the test section. Irradiated crack-arrest specimens were prepared using Methods 1, 3, and 4. Method 1 was the most successful, while Method 4 was the least successful. This paper will discuss some of the reasons for the success, or lack of, as well as the results of testing both a high-copper weldment and a low-copper forging in terms of the shift and shape of the Ka toughness curve compared to the Charpy V-notch shift. The present ASTM Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, KIa, of Ferritic Steels (E 1221-88) validity criteria will also be discussed in light of the results.