Environmental Engineering Reference
In-Depth Information
1.4.4 Reactor pressure vessel (RPV)
The RPV of a PWR is a cylindrical vessel with two hemispherical shells -
one at the top, bolted with fl ange, and one at the bottom, welded - which
contains the core through which pressurized light water is circulated at an
average temperature and pressure of 300°C and 16 MPa, respectively. The
inner surface of the cylindrical vessel is lined with a thin layer (thickness
around 3-10 mm) of austenitic steel (SAE 308/309) to protect the vessel
from corrosion. The vessel is made from plates of low alloy steel (typically
ASTM SA302/SA533B or ASME SA508) with a thickness of about 225
mm. Although many materials are acceptable for reactor vessels accord-
ing to Section III of the ASME Code, the special considerations pertain-
ing to fracture toughness and radiation effects limit the basic materials
for most parts of vessels to SA533 Grade B Class 1, SA508 Class 2 and
(a)
200
100
0
10
18
10
19
10
20
5
Neutron fluence (n/cm
2
, >1 MeV)
5
(b)
60
0.30%
0.25%
50
40
30
0.35%
0.20%
Upper limit
0.15%
0.10%
20
10
10
18
10
19
10
20
5
5
Neutron fluence (n/cm
2
, >1 MeV)
1.35
Trend curves predicting (a) the increase in transition temperature
and (b) the decrease in upper shelf energy as a function of copper
concentration and as a function of neutron fl uence.
93
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