Shell-like features

Shell-like Features and Charge Localization in Protonated Helium Clusters a Density Functional Study... 

Shell-like features and charge localization in protonated helium clusters 103... 

Delayed Reheat Cracking (DRC) was the main mechanism responsible for the cracking problem at 500 C to 520°C in the weldments of the PFR reheater and superheater shells. This is also the case for cracking in secondary pipework weldments in Phenix and it was a major contributory factor in two craqking incidents in PFR secondary pipework which contained notch-like features. All of these incidents have involved the Ti-stabilised Type 321 stainless steel. 

One can note some interesting features from these trajectories. For example, the Mulliken population on the participating atoms in Figure 1 show that the departing deuterium canies a full electron. Also, the deuterium transferred to the NHj undergoes an initial substantial bond stretch with the up spin and down spin populations separating so that the system temporarily looks like a biradical before it settles into a normal closed-shell behavior. 

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