Nanostructure Self-Organization as Cause of Wavelike Radiation Embrittlement of the RPV Steel

Influence of neutron irradiation on reactor pressure vessel (RPV) steel degradation are examined with reference tothe possible reasons of the substantial experimental data scatter and furthermore-nonstandard (non-monotonous)and oscillatory embrittlement behavior. In our glance this phenomenon may be explained by presence of the wavelikerecovering component in the embrittlement kinetics.In our opinion controversy in the estimation on neutron flux on radiation degradation impact may be explained bypresence of the wavelike component in the embrittlement kinetics. Therefore flux effect manifestation depends onfluence level. At low fluencies radiation degradation has to exceed normative value, then approaches to normativemeaning and finally became sub normative. As a result of dose rate effect manifestation peripheral RPV’s zones insome range of fluencies have to be damaged to a large extent than situated closely to core.Moreover as a hypothesis we suppose that at some stages of irradiation damaged metal have to be partially restoredby irradiation i.e. neutron bombardment. Nascent during irradiation nanostructure undergo occurring once orperiodically evolution in a direction both degradation and recovery of the initial properties. According to ourhypothesis at some stage(s) of metal nanostructure degradation neutron bombardment became recovering factor. Asa result oscillation arise that in tern lead to enhanced data scatter. In this case we have to consider irradiation as arecovery factor.Disclosure of the steel degradation oscillating is a sign of the steel nanostructure cyclic self-recovery transformationas it take place in self-organization processes.