Anomalous Hardening in Model Alloys and Steels Thermally Aged at 290°C and 350°C: Implications to Low Flux Irradiation Embrittlement

2009 ◽  
pp. 88-88-14 ◽  
Author(s):  
GR Odette ◽  
GE Lucas ◽  
D Klingensmith
Keyword(s):  
Irradiation Embrittlement ◽  
Anomalous Hardening

Verification of Warm Prestressing Effect Under a Pressurized Thermal Shock (PTS) Event

1994 ◽  
Vol 116 (3) ◽  
pp. 267-273 ◽  
Author(s):  
H. Okamura ◽  
G. Yagawa ◽  
T. Hidaka ◽  
Y. Urabe ◽  
M. Satoh ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Irradiation Embrittlement ◽  
Predictive Equations ◽  
Warm Prestressing ◽  
Pressurized Thermal Shock ◽  
Reactor Steels ◽  
Fracture Tests ◽  
Integrity Analysis ◽  
Temperature Margin ◽  
Reactor Pressure

Fracture tests for the verification of WPS (warm prestressing) effect were carried out by using large flat specimens and big compact specimens with low toughness. In the case of monotonical KI increasing during cooling, the specimen broke within the scatter band of KIC. On the other hand, when KI was decreasing during cooling, the specimens did not break even if KI values were beyond the scatter band of KIC. That is, WPS effect was confirmed even for the low toughness steel like reactor pressure vessel wall under neutron irradiation. Also, KI values at fracture can be predicted by Chell’s theory. By applying WPS effect and the predictive equations for irradiation embrittlement for Japanese PWR reactor steels to the PTS integrity analysis, much more temperature margin can be expected.

Verification of Probabilistic Fracture Mechanics Analysis Code for Reactor Pressure Vessel

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Yinsheng Li ◽  
Genshichiro Katsumata ◽  
Koichi Masaki ◽  
Shotaro Hayashi ◽  
Yu Itabashi ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Working Group ◽  
Power Plants ◽  
Structural Integrity ◽  
Pressure Vessels ◽  
Irradiation Embrittlement ◽  
Energy Agency ◽  
Probabilistic Fracture Mechanics ◽  
Integrity Assessments ◽  
Reactor Pressure

Abstract Nowadays, it has been recognized that probabilistic fracture mechanics (PFM) is a promising methodology in structural integrity assessments of aged pressure boundary components of nuclear power plants, because it can rationally represent the influencing parameters in their inherent probabilistic distributions without over conservativeness. A PFM analysis code PFM analysis of structural components in aging light water reactor (PASCAL) has been developed by the Japan Atomic Energy Agency to evaluate the through-wall cracking frequencies of domestic reactor pressure vessels (RPVs) considering neutron irradiation embrittlement and pressurized thermal shock (PTS) transients. In addition, efforts have been made to strengthen the applicability of PASCAL to structural integrity assessments of domestic RPVs against nonductile fracture. A series of activities has been performed to verify the applicability of PASCAL. As a part of the verification activities, a working group was established with seven organizations from industry, universities, and institutes voluntarily participating as members. Through one-year activities, the applicability of PASCAL for structural integrity assessments of domestic RPVs was confirmed with great confidence. This paper presents the details of the verification activities of the working group, including the verification plan, approaches, and results.

Prediction of irradiation embrittlement of vanadium alloyed low nickel steel for future reactors

2011 ◽  
Vol 416 (3) ◽  
pp. 327-330 ◽  
Author(s):  
A. Kryukov ◽  
L. Debarberis ◽  
P. Hähner ◽  
F. Gillemot ◽  
F. Oszvald
Keyword(s):  
Nickel Steel ◽  
Irradiation Embrittlement

A regulatory view of irradiation embrittlement

1993 ◽  
Vol 54 (1-2) ◽  
pp. 279-292
Author(s):  
F.M.D. Boydon ◽  
B. Hemsworth
Keyword(s):  
Irradiation Embrittlement

Orientation Dependent Strength and Cross-Slip Structure of Ordinary Dislocations in Single Crystal γ-Ti-56A1

1998 ◽  
Vol 552 ◽  
Author(s):  
Q. Feng ◽  
S. H.
Keyword(s):  
Single Crystal ◽  
High Temperatures ◽  
Slip Plane ◽  
Forward Direction ◽  
Orientation Dependence ◽  
Cross Slip ◽  
Dislocation Loops ◽  
Single Slip ◽  
Anomalous Hardening ◽  
Double Cross

ABSTRACTThe temperature as well as orientation dependence in anomalous hardening occurs in single crystal Ti-56AI between 673K and 1073K under single slip of ordinary dislocations. The ordinary dislocations (1/2<110]) are gliding not only on (111) plane but also on (110) plane in the temperature range where the anomalous hardening occurs in single crystal Ti-56A1. The TEM study shows that the (110) cross-slip of ordinary dislocations is a double cross-slip in nature in which first, the dislocations cross-slip from the primary (111) slip plane to (110) plane followed by cross-slipping again onto another primary slip plane. This double cross-slip leaves a pair of edge segments 'superjogs' in (110) planes. It appears that these superjogs are immobile in the forward direction and act as pinning points. Furthermore, these pinning points would act as a Frank-Read source for the double cross-slipped dislocations, which generate dislocation loops as well as dislocation dipoles. The pinning structure, multiplane dislocation loops, and dipoles of double cross-slip origin all contribute to anomalous hardening at high temperatures in this material.

Development of Toughened, Fine Grained, Recrystallized W-1.1%TiC

2021 ◽  
Vol 1024 ◽  
pp. 103-109
Author(s):  
Shunsuke Makimura ◽  
Hiroaki Kurishita ◽  
Koichi Niikura ◽  
Hun Chea Jung ◽  
Hiroyuki Ishizaki ◽  
...  
Keyword(s):  
Melting Point ◽  
Low Temperature ◽  
Fracture Strength ◽  
Room Temperature ◽  
Target Material ◽  
High Density ◽  
High Melting ◽  
High Melting Point ◽  
Irradiation Embrittlement ◽  
Fine Grained

Tungsten (W) is a principal candidate as target material because of its high density and extremely high melting point. W inherently has a critical disadvantage of its brittleness at around room temperature (low temperature brittleness), recrystallization embrittlement, and irradiation embrittlement. TFGR (Toughened, Fine Grained, Recrystallized) W-1.1%TiC has been considered as a realized solution to the embrittlement problems. We started to fabricate TFGR W-1.1%TiC in 2016 under collaboration between KEK and Metal Technology Co. LTD (MTC). The TFGR W-1.1%TiC samples were successfully fabricated in June, 2018. As a result, the specimen showed slight bend ductility and 2.6 GPa of fracture strength.

Surveillance Program for Irradiation Embrittlement of Reactor Pressure Vessels in Japan

2018 ◽  
pp. 202-218
Author(s):  
Takatoshi Hirota ◽  
Takashi Hirano ◽  
Masayuki Uchihashi ◽  
Tetsuya Toyoda ◽  
Shinichi Takamoto ◽  
...  
Keyword(s):  
Pressure Vessels ◽  
Surveillance Program ◽  
Irradiation Embrittlement ◽  
Reactor Pressure
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