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American Society for Testing and Materials

Microencapsulated fuel technology for commercial light water and advanced reactor application

Development of new materials for current and advanced reactor concepts is hampered by long lead times and high cost of reactor irradiations coupled with the paucity of test reactors. Ion irradiation offers many advantages for emulating the microstructures and properties of materials irradiated in reactors but also poses many challenges. Nevertheless, there is a growing body of evidence, primarily for light ion (proton) irradiation showing that many, if not all of the features of the irradiated microstructure and properties, can be successfully emulated by careful selection of irradiation parameters based on differences in the damage processes between ion and neutron irradiation. While much less has been done to benchmark heavy- or self-ion irradiation, recent work shows that under certain conditions, the complete suite of features of the irradiated microstructure can be emulated. This study summarizes the contributions of ion irradiation to our understanding of irradiation effects, the options for emulating radiation effects in reactors, and experience with both proton irradiation and heavy ion irradiation.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0884291415000734

Challenges to the use of ion irradiation for emulating reactor irradiation

Zirconium Alloys in Nuclear Applications

In this chapter, the effects of neutron irradiation on zirconium alloys are described. Irradiation effects on the microstructure are first discussed, describing damage creation and point-defect evolution leading to loops formation and secondary-phase evolution under irradiation. Then, in the second part, irradiation effects on postirradiation mechanical behavior and deformation mechanisms, especially during tensile test and also after postirradiation thermal treatment or postirradiation creep tests, are given. Finally, the in-reactor deformation behavior, growth, and irradiation creep, as well as the related deformation mechanisms, are analyzed.

Radiation Effects in Zirconium Alloys

Irradiation creep and growth of zirconium alloys: A critical review

Grain boundary sinks in neutron-irradiated Zr and Zr-alloys

Precipitation in Zr-2.5Nb enhanced by proton irradiation

Delayed hydride cracking in zirconium alloys in a temperature gradient

Zirconium alloys are susceptible to a stable cracking process called delayed hydride cracking (DHC). DHC has two stages: (a) crack initiation that requires a minimum crack driving force (the threshold stress intensity factor, K{sub IH}) and (b) stable crack growth that is weakly dependent on K{sub l}. The value of K{sub lH} is an important element in determining the tolerance of components to sharp flaws. The rate of cracking is used in estimating the action time for detecting propagating cracks before they become unstable. Hence, it is important for reactor operators to know how these properties change during service in reactors where the components are exposed to neutron irradiation at elevated temperatures. DHC properties were measured on a number of components, made from the two-phase alloy Zr-2.5 Nb, irradiated at temperatures in the range of 250 to 290 C in fast neutron fluxes (E {>=} 1 MeV) between 1.6 {times} 10{sup 17} and 1.8 {times} 10{sup 18} n/m{sup 2} {center_dot} s to fluences between 0.01 {times} 10{sup 25} and 9.8 {times} 10{sup 25} n/m{sup 2}. The neutron irradiation reduced K{sub IH} by about 20% and increased the velocity of cracking by a factor of about five. The increase in crackmore » velocity was greatest with the lowest irradiation temperature. These changes in the rack velocity by neutron irradiation are explained in terms of the combined effects of irradiation hardening associated with increased -type dislocation density, and {beta}-phase decomposition. While the former process increases crack velocity, the latter process decrease it. The combined contribution is controlled by the irradiation temperature. X-ray diffraction analyses showed that the degree of {beta}-phase decomposition was highest with an irradiation temperature of 290 C while -type dislocation densities were highest with an irradiation temperature of 250 C.« less

CE Coleman

Papers

Irradiation creep and growth of zirconium alloys: A critical review

Grain boundary sinks in neutron-irradiated Zr and Zr-alloys

Precipitation in Zr-2.5Nb enhanced by proton irradiation

Delayed hydride cracking in zirconium alloys in a temperature gradient

The Effect of Fluence and Irradiation Temperature on Delayed Hydride Cracking in Zr-2.5Nb