Thermal fatigue crack growth : Modelling and experimental verification
The first wall of tokamak type fusion reactors such as NET or ITER, which suffer thermal fatigue damage as a result of discontinuous loading due to plasma disruptions, have been investigated. As well as a general purpose out-of-pile testing rig, the experimental testing facilities of the project included an in-pile rig for measuring the crack growth rate in tubular components exposed to thermal fatigue conditions under neutron irradiation in the HFR reactor. The crack growth rates in the in-pile and out-of-pile rig were measured in situ by means of the AC and DC potential drop techniques, respectively. A series of notch initiated crack growth tests was run in the out-of-pile rig on the 316L steel considered for first wall application in NET. The test results served as a thermal fatigue life database, and as a basis for the verification of the model prediction of crack growth rates under LEFM conditions. The model encompassed temperature and stress calculations over the uncracked tube wall by means of a finite element formulation. The stress intensity factors were obtained by means of a combined line spring/weight function method. Growth rates of longitudinal surface cracks in the time and space variable temperature and stress field in the tube wall were calculated on the basis of the Paris law. The model has been incorporated in the computer code PREDI-N.
Bibliographic Reference: Paper presented: 6th International Conference on Fusion Reactor Materials (ICFRM-6), Stresa (IT), September 27 - October 1, 1993
Availability: Available from (1) as Paper EN 37900 ORA
Record Number: 199311433 / Last updated on: 1994-11-28
Original language: en
Available languages: en