Radiation embrittlement solute clusters

Regarding the neutron fluence value at the time of annealing, no substantial effects were found. Residual embrittlement, as well as the rate of further re-embrittlement, is practically independent of this neutron fluence. The lateral (horizontal) shift approach was also confirmed in the IAEA Round Robin Exercise on radiation embrittlement of WWER-440 weld metal, as shown in Rg. 5.16. The microstructure investigation results demonstrate that copper clusters, which are formed in material under primary irradiation, are not recovered during annealing to a structure of solid solution such as that in the unirradiated state. 

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