So my lecturer was discussing the use of robotics to deal with the fallout from either decommissioned nuclear reactors or reactors that have gone into meltdown (the example here being Fukushima). Of the hazards that were mentioned, the actual radioactivity was left out. From what I can remember of high school/ college physics wouldn't the radioactive environment interfere with the radio waves used to communicate with the robots? I know they are mostly autonomous due to the challenging environment, but wouldn't this still damage feedback? Thanks
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$\begingroup$ the radioactive environment interferes with the operation and may even destroy the semiconductor electronics. $\endgroup$– hyportnexCommented Oct 2, 2017 at 13:07
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The radioactivity in form of electromagnetic waves would not interfere with radio waves because they have very different energies. Gamma emissions from nuclei (prompted by different radioactive decays) would generally have 100keV-10MeV energies, which puts their wavelengths at 10pm-1fm, while radio-waves have wavelengths of 1mm-10km wavelength. In time scales, a radio-wave antenna is sensitive to time variations between 1ms-10s, while gamma radiation will fluctuate in times smaller than $10^{-18}s$.
However, the dose is what usually causes problems, since such radiation can affect the semiconductor structures and can produce both long range damage and and glitches in real time, if the radiation levels are as high as in Fukushima.
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$\begingroup$ Dose is, in my understanding, related to humans; irrelevant in this case. To add: in the design of these robots the radioactive hazards are noticed: avoiding vulnerable structures and using protective layers. $\endgroup$ Commented Oct 2, 2017 at 13:56
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1$\begingroup$ Dose, is used both for humans and matter. The differences are somewhat expressed by using different units (Sievert for humans, Gray in general) since for humans is important to know how different forms of radiation are effective on ionizing inside the human body, which is accounted in Sievert. Dose $\endgroup$– rmhleoCommented Oct 2, 2017 at 14:16
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1$\begingroup$ While their is awareness of the effect of radiation on electronics, this is still a matter of study, and research, and it is not a solved question, neither from research nor from engineering points of view. Shielding is possible and effective for alpha and beta radiation from reactor fuel, but for gamma rays and neutrons, the shielding needs to be heavier and the intensities might be such that shielding is not an option. Especially when both gamma and neutrons are present, the problem is more complicated since good shielding material for gamma rays is neutron fissile, or neutron activated. $\endgroup$– rmhleoCommented Oct 2, 2017 at 14:28
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$\begingroup$ Gamma rays are the concern. (The long-lived fission products that are still radioactive after a reactor shuts down aren't neutron emitters, and any thin robot shell will block alpha and beta radiation.) Gamma rays require a few feet of steel shielding to block, so the main strategy for radiation-hardened electronics isn't shielding. Rather it's to design with larger semiconductor structures that aren't as vulnerable to a few atoms being knocked around. (E.g. NASA intentionally uses old processors in space probes.) Also some possible semiconductors are a bit less vulnerable than silicon. $\endgroup$– LukeCommented Oct 8, 2020 at 5:44