Fracture tests for the verification of WPS (warm prestressing) effect were carried out by using large flat specimens with very low toughness. Tensile and bending loads and thermal shock were applied simultaneously to the specimens with the realistically postulated flaw and the two times larger one in order to make the maximum KI cross the lower bound of KIC data. During the tests, loading was controlled to simulate the shape of KI versus temperature curve for the postulated PTS transient. Both the specimens did not break within the scatter band of KIC when KI was decreasing during cooling. KI values at fracture by reloading were beyond the upper bound of KIC. That is, the effectiveness of WPS was directly demonstrated for the PTS transients. Also, KI values at fracture can be predicted by Chell’s theory. As the test results, Japanese PWRs have sufficient temperature margin against PTS.

1.
Bryan, R. H., Bass, B. R., Bolt, S. E., Bryson, J. W., Edmonds, D. P., McCulloch, R. W., Merkle, J. G., Nanstad, R. K., Robinson, G. C., Thorns, K. R., and Whitman, G. D. 1985, “Pressurized-Thermal Shock Test of 6-in-Thick Pressure Vessels. PTSE-1: Investigation of Warm Prestressing and Upper-Shelf Arrest,” NUREG/CR-4106 (ORNL-6135), Oak Ridge National Laboratory, Oak Ridge, TN.
2.
Bryan, R. H., Bass, B. R., Bolt, S. E., Bryson, J. W., Edmonds, D. P., McCulloch, R. W., Merkle, J. G., Nanstad, R. K., Robinson, G. C., Thoms, K. R., and Whitman, G. D., 1987, “Pressurized-Thermal Shock Test of 6-in-Thick Pressure Vessels. PTSE-2: Investigation of Low Tearing Resistance and Warm Prestressing,” NUREG/CR-4888 (ORNL-6377), Oak Ridge National Laboratory, Oak Ridge, TN.
3.
Buchalet, C. B. and Bamford, W. H., 1975, “Method for Fracture Mechanics Analysis of Nuclear Reactor Vessels under Severe Thermal Transients,” Paper No. 75-WA/PVP-3, ASME Winter Annual Meeting, Houston, TX, November 30-December 4.
4.
Chell, G. G., Haigh, J. R., and Vitek, V., 1979, “A Theory of Warm Prestressing: Experimental Validation and the Implications for Elastic-Plastic Failure Criteria,” CERL Lab. Note RD/L/N63/79, Leatherhead, UK.
5.
Chell
G. G.
,
Haigh
J. R.
, and
Vitek
V.
,
1981
, “
A Theory of Warm Prestressing: Experimental Validation and Implementations for Elastic Plastic Failure Criteria
,”
International Journal of Fracture
, Vol.
17
, No.
1
, pp.
61
81
.
6.
Curry, D. A., 1979, “A Micromechanistic Approach to the Warm Prestressing of Ferritic Steels,” CERL Lab. Note RD/L/N/03/79, Surrey, UK.
7.
Formby, C. L., and Griffiths, J. P., 1977, “The Role of Residual Stress in the Fracture of Steel,” CEGB Research Report NW/SSD/RR/131/77, Berkeley, UK.
8.
Hollstein
T.
,
Blauel
J. G.
,
Kienzler
R.
, and
Nagel
G.
,
1986
Use of Load Path Dependent Material Fracture Toughness Values (WPS) in the Safety Analysis RPV State
,”
Nuclear Engineering and Design
, Vol.
94
, pp.
233
239
.
9.
Ishino
S.
,
Kawakami
T.
,
Hidaka
T.
, and
Satoh
M.
,
1990
, “
The Effect of Chemical Composition on Irradiation Embrittlement
,”
Nuclear Engineering and Design
, Vol.
119
, pp.
139
148
.
10.
Loss, F. J., 1978, “Structural Integrity of Water Reactor Pressure Boundary Components,” Progress Report to Aug. 1977, NRL Memo Report 3700, Washington, DC.
11.
Mishima
Y.
,
Ishino
S.
,
Ishikawa
M.
,
Okamura
H.
,
Yagawa
G.
,
Hidaka
T.
,
Yamamoto
T.
,
Sanoh
J.
,
Koyama
K.
,
Iida
M.
,
Urabe
Y.
,
Sato
M.
, and
Tomimatsu
M.
,
1994
, “
PTS Integrity Study in Japan
,”
International Journal of Pressure Vessel and Piping
, Vol.
58
, pp.
91
101
.
12.
Okamura
H.
,
Yagawa
G.
,
Hidaka
T.
,
Urabe
Y.
,
Satoh
M.
,
Tomimatsu
M.
, and
Iida
M.
,
1994
, “
Verification of WPS Effect under a PTS Event
,”
ASME JOURNAL OF PRESSURE VESSEL TECHNOLOGY
, Vol.
116
, pp.
267
273
.
13.
Pickles
B. W.
, and
Cowan
A.
,
1983
, “
A Review of Warm Prestressing Studies
,”
International Journal of Pressure Vessel and Piping
, Vol.
14
, pp.
95
131
.
14.
Stonesifer, R. B., and Rybicki, E. F., 1987, “Development of Models for Warm Prestressing,” NUREG/CR-4491 (MEA-2122), Material Engineering Associates, Inc., Lanham, MD.
15.
Theiss, T. J., Rolfe, S. T., and Shum, D. K. M., 1992, “Shallow-Crack Toughness Results for Reactor Pressure Vessel Steel,” Shallow Crack Fracture Mechanics, Toughness Tests and Applications, Cambridge, U.K., September 23–24.
This content is only available via PDF.
You do not currently have access to this content.