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The aim of this work is to characterize the oxidation behaviour of different nickel-base alloys exposed to high-temperature and high-pressure water for short oxidation times. The behaviour of Alloy 600 (74% Ni, 16% Cr, 9% Fe), Alloy 690 (60% Ni, 30% Cr, 9% Fe) and Alloy 800 (47% Fe, 32% Ni, 21% Cr) exposed to simulated, pressurised water reactor primary water at 325• C has been compared. From the combination of chemical and structural data obtained by XPS, nuclear reaction analysis and scanning electron microscopy, the chemical composition and the morphology of the oxide formed on the surfaces have been determined. All alloys present a duplex oxide layer composed of Fe-rich crystals in the external layer and an inner Cr-rich layer that is compact and continuous.

Several crack tip stress intensity factor solutions have been published for semielliptic. surface breaking cracks in plates subjected to tension or bending forces. These solutions do not agree with each other particularly well and the basis for choosing which one is the best has not been established. In this paper, the development of fatigue crack shape is used as a diagnostic tool to test the accuracy of these theoretical stress intensity solutions in predictive fatigue crack growth calculations. Those solutions giving the best engineering estimate of crack tip stress intensity factors are identified. Single equations are also given for each loading case a t the deepest point or surface intersection point of semi-elliptic cracks in order to facilitate calculations on programmable calculators. A rational basis for calculating the progress of a crack which snaps through the thickness and continues to propagate in a stable way by fatigue is suggested.Nomenclature plate or cylinder wall thickness plate width inside radius of a cylinder outside radius of a cylinder crack depth, half the minor axis of a semi-elliptical crack half surface length or half the major axis of a semi-elliptical crack crack tip stress intensity factor crack tip stress intensity at surface intersection points of a semi-elliptical crack, 8 = 0 crack tip stress intensity factor at the deepest point of a semi-elliptical crack, 0 = 742 front face magnification factor as a function of 0 product of the front face and finite thickness magnification factors as a function of 0 fatigue crack growth rate per cycle oscillating range of the stress intensity factor angle subtended between any radius and the surface (or major axis) uniform tension or membrane stress pure bending stress

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A home-based self-help rehabilitation package is an effective tool alongside hospital-based rehabilitation classes and can be given to all age groups.