Properties of zirconium alloys and their applications in light water reactors (LWRs) - Materials' Ageing and Degradation in Light Water Reactors - page 120

0.5

0.45

0.4

RX-25
RX-300
CW-25
CW-300

0.35

0.3

0.25

0.2

0.15

0.1

0.05

0 0

50 100 150

Hydride blister depth ( μ m)

200 250 300

4.32 Local fracture strain versus hydride blister thickness for both cold
worked stress relieved (CWSR) and recrystallized (RX) Zircaloy-4 sheet
tested at either 25 ° C or 300 ° C. All data are for 3 mm blisters (Pierron
et al ., 2003).

140

120

100

80

60

￿ ￿ ￿ ￿ ￿ ￿

40

Unirradiated
Irradiated: 1.6-9.5 × 10 21 n/m 2

20

0 250 500

Hydrogen, ppm

750 1000

4.33 Strength as a function of hydrogen content for irradiated and
unirradiated Zircaloy-2 tested at 332 ° C (605K) (Wisner & Adamson, 1998).

The factors that affect hydride reorientation in irradiated cladding are:

￿ hoop stress, or tensile and compressive stresses;

￿ maximum temperature;

￿ cool-down rate and fi nal temperature;