Post-irradiation annealing

GE. Youngblood, D.J, Senor, and R.H, Jones, Effects of Irradiation and Post-irradiation Annealing on the Thermal Conductivity/Diffusivity of Monolithic SiC and F-SiC/SiC Composites, J. Nucl. Mater, 329-333, 507-12 (2004),... 

PA studies on RPV steels are important because they have the potential to provide information on matrix defects. However, since interpretation of the data from complex commercial steels is difficult, many studies have focused on model alloys. In Section 9.11.1 we include a brief review of a selection of PA data from the literature, focusing first on model alloys and then on steels. It is shown that, in combination with post-irradiation annealing and other microstructural techniques, positron annihilation techniques can help elucidate the nature of the positron traps. 

Microstructural Characterization of Reactor Pressure Vessel Steels Post-Irradiation Annealing Experiments Joint EPRI-CRIEPI RPV Embrittlement Studies (1999-2004), Electric Power Research Institute, Palo Alto, CA, 2004, 1003531, and CRIEPI, Tokyo, Japan, Q980401. 

The release of tritium from irradiated oxide powders was studied by the method of post-irradiation annealing. At 400 to 660C, the release was a diffusion-controlled process. The diffusion coefficient of T in the two powders used was given by ... 

C by using a post-irradiation annealing technique. The irradiation dose was 1.2 x 10fissions/cm. The effect of the O potential upon the diffiisivity in UO2 was also... 

Post-irradiation annealing results [55] suggest that microvoids or vacancy clusters are responsible for about 20-30% of the embrittlement effect in commercial RPV steels. Although such defects were detected in irradiated model alloys, there is no solid evidence for their detection in commercial RPV steels. 

In addition to its effect of increasing the irradiation sensitivity of steel, there are indications that the high Cu content in RPV steel retards the recovery of its mechanical properties during the post-irradiation annealing process. 

Irradiations at high temperature or post-irradiation annealing resulted in recovery of the microstructure and hardness. This recovery was incomplete after 500 C annealing. 

It is noteworthy that no PBG effect is visible from the as-irradiated samples in both dot- and rod-PhCs. After post-irradiation annealing, transmission dips show up, attributed to the smoothing of internal structures which reduced scattering... 

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