Review on synergistic damage effect of irradiation and corrosion on reactor structural alloys

The synergistic damage effect of irradiation and corrosion of reactor structural materials has been a prominent research focus.This paper provides a comprehensive review of the synergistic effects on the third-and fourth-generation fission nuclear energy structural materials used in pressurized water reactors and molten salt reactors.The competitive mechanisms of multiple influencing factors,such as the irradiation dose,corrosion type,and environmental temperature,are summarized in this paper.Conceptual approaches are proposed to alleviate the synergistic damage caused by irradiation and corrosion,thereby promoting in-depth research in the future and solving this key challenge for the structural materials used in reactors.

Behaviors of fine(IG-110)and ultra-fine(HPG-510)grain graphite irradiated by 7 MeV Xe^26+ions

Developing a molten salt reactor needs molten salt-impermeable nuclear graphite. Ultra-fine grain graphite is a good choice as it is better in permeability than fine grain graphite. In this paper, ultra-fine grain graphite(HPG-510) and fine grain graphite(IG-110) samples are irradiated at room temperature by 7 MeV Xe ions to doses of 1 × 10^(14)-5 × 10^(15) ions/cm^2. Scanning electron microscopy, transmission electron microscopy(TEM), Raman spectroscopy and nano-indentation are used to study the radiation-induced changes. After irradiation of different doses, all the HPG-510 samples show less surface fragment than the IG-110 samples. The TEM and Raman spectra,and the hardness and modulus characterized by nano-indentation, also indicate that HPG-510 is more resistant to irradiation.

Investigation on hydrogen absorption/desorption properties of as-cast La(1-x)Mg_xNi4.25Al0.75(x=0.0, 0.1, 0.2, 0.3) alloys for tritium storage

La_((1-x))Mg_xNi_(4.25)Al_(0.75)(x = 0.0, 0.1, 0.2, 0.3)alloys for tritium storage were prepared by a method of electromagnetic induction melting. The crystal structure and hydrogen storage performance of the as-cast alloys were investigated. The results showed that a single phase of La Ni_4Al was in the alloys with x = 0.0 and 0.1 and that LaNi_4Al and second phase of(La,Mg)Ni)_3 and AlNi_3 were in the alloys with x = 0.2 and 0.3. On the other hand, the plateau pressures of P–C isotherms of the alloys were increased with the rise of the x value from 0.2 to 0.3 and the hydrogen storage capacity was obviously degraded simultaneously. It was found that the alloy had faster absorption kinetics as the proportion of Mg increased from 0.1 to 0.3.

Ion-beam-assisted characterization of quinoline-insoluble particles in nuclear graphite

The irradiation behavior of graphite is essential for its applications in the nuclear industry.However,the behavioral differences of graphite remain obscure because of the very limited comprehension of its microstructural differences.One typical structure,the quinoline-insoluble(QI)particle,was investigated using IG-110 and NBG-18 graphite.After irradiation,the QI particles on the polished surface were proven to become hillocks,which were easily identifiable via scanning electron microscopy(SEM).Thus,a method that combined ion irradiation and SEM characterization was proposed to study the distribution and concentration of QI particles in graphite.During irradiation,the QI particles were found to evolve into densified spheres,which were weakly bonded with the surrounding graphite structures,thereby indicating that the densification of QI particles did not evidently contribute to graphite dimensional shrinkage.A much higher concentration of QI particles in NBG-18 than IG-110,which was suggested to be responsible for the smaller maximum dimensional shrinkage of former over the latter during irradiation,was characterized.