Environmental Engineering Reference
In-Depth Information
Fully recrystallized, RP
0.2(400°C)
= 120 N/mm
2
f
1
= 0.04-0.05
Partially recrystallized, RP
0.2(400°C)
= 270 N/mm
2
f
1
= 0.04-0.05
Stress relieved, RP
0.2(400°C)
= 350 N/mm
2
f
1
= 0.04-0.05
1.5
-quenched, RP
0.2(400°C)
=154 N/mm
2
f
1
= 0.23
1
0.5
0
0.0E+00
5.0E+21
Fast neutron fluence (>1 MeV, n/cm
2
)
1.0E+22
1.5E+22
2.0E+22
4.62
Irradiation growth of Zircaloy at 300
°
C measured on samples with
different yield strength (CW, recrystallization) and different textures
(f1). (Source: Reprinted, with permission, from Garzarolli
et al.
(1989,
1996), copyright ASTM International, 100 Barr Harbor Drive, West
Conshohocken, PA 19428.)
constant volume assumptions may not be valid. At low fl uence the two
assumptions are reasonable, but at high fl uence the transverse strain is not
zero (as would be predicted by the
f
x
value) and the sum of the strains is
strongly positive. It is also noted that cold worked material and recrystal-
lized material have similar growth behaviour at high temperatures. It is fur-
ther noted that the temperature of this irradiation is at the upper range
(>378ºC) expected for even a hot PWR.
For the high temperature data presented in Fig. 4.64, STEM studies
revealed grain boundary cavities and occasional IG voids (Tucker
et al
., 1984 )
which may explain the observed change of volume. Other studies have not
reported cavities or voids at very high fl uence at 290°C (363K) (Mahmood
et al
., 2000) or high fl uence at 350°C (623K). Holt & Causey (2004) reported
that for Zr-2.5Nb there is a small volume increase (0.05-0.1%) at low fl u-
ence, but at high fl uence the volume change was close to zero.
Materials chemistry of the alloy
Irradiation growth of RXA Zr-Nb alloys (E110, E635, NSF, M5, ZIRconium
Low Oxidation (ZIRLO)) all exhibit a resistance to formation of <c> loops
at low or intermediate fl uence and as a result have lower growth than
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