ML20090K386
| ML20090K386 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 12/12/1983 |
| From: | Mager T, Fabian Thomas WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | |
| References | |
| A-093, A-93, NUDOCS 8405240190 | |
| Download: ML20090K386 (3) | |
Text
e mv.
r
-n p
~
7:1 5 7.=ED
~
)
t s1 1'JiR 2 3 n
aa1:B% $.
ga:
v
/
- 1EcY3G,/,
/ng.)Q, p?
q'q i3 i
HEAVY SECTION STEEL TECHNOLOGY PROGRAM I!
1 TECHNICAL REPORT NO. 5 g
P (NOVEMBER, 1969) h EVALUATION BY LINEAR ELASTIC g
FRACTURE MECHANICS OF RADIATI N DAMAGE TO i
5 PRESSURE VESSEL STEELS
- 4
?
by b
p T. R. Mager i
F. O. Thomas j
[$i
.9 5
.i n
October 1969 Y"
f.
- Research sponsored by the U. S. Atomic Energy Commission under contract in part with the Union Carbide Corporation.
[.
i h
sy
)y
\\
/
/
ff APPROVED:
/.
APPROVED; W. S. H 6 elton, Manager
'B. Keh i.
Plant Materials Engineering
\\
Project Engineer g
Fracture Mechanics Programs s
t k
l WESTINGHOUSE ELECTRIC CORPORATION Nuclear Energy Systems g
PWR Systems Divfaion
}i l
P. O. Box 355 l
Pittsburgh, Pennsylvania 15230 I
h
~
8405240190 831212 PDR ADOCK 05000 q
L 0
4 A
%}
4 l
~
I F
s i
Because the microstructure and mechanical properties of the interior of the 12-inch-thick plate (1/4 and 1/2 thickness) were essentially the same and t
each locathca was isolated in a given capsule, the influence of the flux level i
can be evaluated.
Capsule No. 5 contained specimens from the quarter thickness
'j t
location of the 12-inch-thick plate and was exposed to a fluence of approxi-mately 4 x 10 ' n/cm while Capsule No. 6 contained specimens from the center thickness and was expxed to a fluence of 1.3 x 10 ' n/cm. When the 1
30 ft-lb transition temperatu're-shift and K values after irradiation are 1
compared, it is evident that 1.3 x 10 ' n/c does not saturate the material with regard to irradiScion damage.
The final objective of the program was to assess the influence of applied i
(
l tensile stress during irradiation on the fracture toughness of the various j
pressure vessel materials. The data for the pre-stressed fracture mechanics
{
specimens are grouped together in Table 41:
From Tables 40 and 41 it would7 I
I t
appear that an applied tensile stress of 26,700 psi during irradiation neither E
enhances nor reduces the radiation embrittlement sensitivity of the pressure f
vessel steels studied. This a consistent with other investigators' data (
based on Charpy V-notch specimen 4 subjected to an applied tensile stress during irradiaticn. The one exception in this investigation was the European forging grade steel. This material exhibited a KIc "*1"* """
E "#
than expected and resulted in an invalid data point. However, if the plastic i
t zone size during the prestressing is taken into consideration, it can be con-i cluded that the apparent erroneous KIc ** * " * ' * " * " *
"#E*
- l plastic zone size at the crack tip during prestressing, rather than the in-l fluence of the applied stress during irradiation.
6.
CONCLUSIONS I
g 1.
Weldment material of A 533, grade B, c1As's 1 steel produced by the j
submerged arc process exibits a higher fracture toughness (KIc) at a given temperature then base plate material of A. 533, grade B.
I class 1 steel when evaluated prior to irradiation.
2.
European 1.2 MLO7 forging grade steel, while exhibiting a somewhat lower resistance to fracture then the weldment material of A 533,
i I
grade B, class 1 steel, exhibits a higher fracture toughness (Kk) at a given temperature than base plate material of A 533, grade B, I
class 1 steel when evaluated prior to irradiation.
I
},
3.
Weldment material of A 533, grade B, class 1 steel produced by the submerged are process was relatively sensitive to neutron exposure.
The 12-inch-thick plate (HSST Plate No.02) of A 533, grade B, class 1 steel and the European 1.2 MD07 forging grade steel were relatively insensitive to neutron exposure. The material from the 8 -inch-thick plate of A 533, grade B, class 1 steel fell in between f
the two extremes of sensitivity.
19 2
4.
After an exposure to a fluence of 1-5 x 10 n/cm, the shift in j
the K versus temperature curve was always less than 30 ft-lb Ic transition temperature shift. ~
~
5.
The material at the top and bottom surfaces of the 12-inch-thick j
plate (HSST Plate No. 2) of A 533, grade B, class 1 steel was considerably tougher than the interior of the plate.
It was con-j cluded that this phenomenon is due to the quench and prolonged temper treatment that the two surfaces underwent during the quenchinz
.f i
of the 12-inch-thick plate.
4
- 6. ' An applied tensile stress during irradiation neither enhanced nor reduced the radiation embrittlement sensitivity of the pressure vessel steels studied.
l I
7.
EXAMPLE PROBLD{
ihe criterion now used by Westinghouse for safe operation of Reactor Pressure
[.s Vessels is that described by P,orse l, which is based on ductile-brittle transition temperature concepts. The transition temperature approach to design, limits the acceptable stresses in the vessel when the vessel tem-perature is below the design transition temperature (DTT). The design transition temperature is defined as NDTT +60*F and is considered to be the crack arrest temperature (CAT) f.: a stress equal to the yield stress of the material. The allowable hoop stress is temperature-dependent, and is defined
f h
69
/ / /
rr
/
/
l
~
/
l?. 'i
_e
- '/\\/!-
/
/
g
., I.\\/ / 3
,ij N, /
e m
- . 6 O' 4
/
/
}~
4
//jl, i
/f? ! ; l l l
/
'?
y! l
' '/
' l,,l cfD 1
,l
??
/
ej f
U 4' 33 - 3
-/
/
t G
_,,l
~Y i
O
..