Microstructure and Modelling of RPV Embrittlement

1996 ◽  
Vol 439 ◽  
Author(s):  
C. A. English ◽  
W. J. Phythian ◽  
R-J. McElroy
Keyword(s):  
Mechanical Properties ◽  
Pressure Vessel ◽  
Experimental Techniques ◽  
Copper Clusters ◽  
Recent Advances ◽  
Pressure Vessel Steels ◽  
Potential Benefits

AbstractIn this paper we review the advances in understanding ofmicrostructural evolution during irradiation in pressure vessel steels. A particular focus is the benefits that arise from combining microstructural techniques on characterising the microstructure, especially the copper clusters. In addition to experimental techniques the importance of developing microstructurally based models linking the microstructural features to mechanical properties behaviour will be demonstrated. This paper will consider the recent advances in understanding in this area, and highlight the potential benefits that can be gained from a thorough understanding of the materials response to irradiation.

Experimental Program to Monitor the Irradiation Induced Embrittlement of the French Reactor Pressure Vessel Steels

2004 ◽  
Author(s):  
Guillaume Chas ◽  
Nathalie Rupa ◽  
Josseline Bourgoin ◽  
Astrid Hotellier ◽  
Se´bastien Saillet
Keyword(s):  
Mechanical Properties ◽  
Pressure Vessel ◽  
Mechanical Tests ◽  
Nuclear Industry ◽  
Experimental Program ◽  
Surveillance Program ◽  
Base Metals ◽  
Vessel Steel ◽  
Pressure Vessel Steels ◽  
Reactor Pressure

By monitoring the irradiation-induced embrittlement of materials, the Pressure Vessel Surveillance Program (PVSP) contributes to the RPV integrity and lifetime assessments. This program is implemented on each PWR Unit in France; it is mainly based on Charpy tests, which are widely used in the nuclear industry to characterize the mechanical properties of the materials. Moreover, toughness tests are also carried out to check the conservatism of the PVSP methodology. This paper first describes the procedure followed for the Pressure Vessel Surveillance Program. It presents the irradiation capsules: the samples materials (low alloy Mn, Ni, Mo vessel steel including base metals, heat affected zones, welds and a reference material) and the mechanical tests performed. Then it draws up a synthesis of the analysis of about 180 capsules removed from the reactors at fluence levels up to 7.1019 n/cm2 (E > 1 MeV). This database gathers the results of more than 10,000 Charpy tests and 250 toughness tests. The experimental results confirm the conservatism of the Code-based methodology applied to the toughness assessment.

Intergranular segregation in pressure-vessel steels

1993 ◽  
Vol 51 ◽  
pp. 854-855
Author(s):  
M.G. Burke ◽  
E.A. Kenik
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Neutron Irradiation ◽  
Pressure Vessel ◽  
Analytical Electron Microscopy ◽  
Nuclear Industry ◽  
Transmission Electron ◽  
Pressure Vessel Steels ◽  
Scanning Transmission ◽  
Induced Changes

The degradation of low alloy pressure vessel steels in the presence of neutron irradiation is of fundamental importance in the nuclear industry. Numerous studies have been performed to evaluate the irradiation-induced changes in mechanical properties, and to a lesser extent, the changes in microstructure, of these pressure vessel materials. Irradiation results in an increase in the ductile to brittle transition temperature and a decrease in the upper shelf energy of the steels. The exact contribution of intergranular segregation to the concomitant degradation in mechanical properties is, however, unclear. To understand the microstructural changes caused by neutron irradiation and to clarify this contribution, it is important to fully characterize the material prior to irradiation. In this initial investigation, the techniques of analytical electron microscopy (AEM), high spatial resolution field emission gun scanning transmission electron microscopy (FEG-STEM) and energy dispersive x-ray spectroscopy (EDS) microanalysis have been employed to evaluate the microstructure of a low alloy steel as a first step in addressing this issue.

Sign in / Sign up

Export Citation Format

Share Document