Radiation effects/damage in structural alloys and ceramics

[Astronuc]

I was reading an old thread - Radiation Damage In metals from Gamma rays - https://www.physicsforums.com/threads/radiation-damage-in-metals-from-gamma-rays.826449/ The thread is long dormant and wasn't productive, but based on what I've learned over the last 5 years, I would change my response to indicate that gamma radiation shouldn't be ignored/dismissed, although apparently it has been somewhat. A colleague showed me some radiographs that could only be explained by the presence of gammas, which lead to some of the research I'm now doing.

A useful resource - https://www.oecd-nea.org/jcms/pl_19620 NEA/NSC/DOC(2015)9 - but it does not address gamma radiation.

Gammas are significant due to the interaction with electrons by the photoelectric effect (low energy), Compton Scattering (moderate energy), and pair production (E > 1.022 MeV). As neutron energy increases, pair production becomes more probable, particularly in the presence of high Z atoms, e.g., Zr, Nb, W, U, Pu. It is the Compton electrons and positron-electron pairs that are significant (I use a term 'Compton cascade'). One challenge in understanding the influence of gamma radiation in a reactor is the presence of neutrons, which cause a lot of damage through atomic displacements. For every fission event, there are two or three neutrons, and either 7 or 8 prompt gammas, not including decay gammas (from fission products) and gammas from radiative capture. Obtaining an approximate neutron energy spectrum (0.01eV to 10 MeV) for a given lattice is relatively simple compared to obtaining a gamma energy spectrum, which is considerable more complex.

Another good reference - Fundamentals of Radiation Materials Science
https://link.springer.com/book/10.1007/978-1-4939-3438-6 (but not much on gamma radiation effects).
Gary Was has taught a lot of folks now working on the subject.

 

[Navin A S]

The presence of gamma radiation is often overlooked in reactor calculations, and can lead to significant errors. For instance, the prediction of thermal conductivity and Young's modulus can be significantly off if the effects of gamma radiation are ignored. Gamma radiation can also cause an increase in hydrogen content, which affects corrosion resistance. The presence of high energy gammas (>1MeV) can also lead to embrittlement.At the end of the day, it's important to recognize and consider the effects of gamma radiation in reactor design and operation, especially in high-flux systems.

 

[raining Pete]

I completely agree with your updated response. While it may have been dismissed in the past, it is clear that gamma radiation cannot be ignored in the study of radiation damage in metals. The presence of neutrons and high Z atoms only adds to the complexity of understanding the effects of gamma radiation. Thank you for providing the additional resources, they will definitely be useful in furthering my understanding of this topic.