radiation

70 Articles

The Radioactive Source Missing In Australian Desert Has Been Found

February 1, 2023 by 66 Comments

Nuclear material is relatively safe when used, stored, and managed properly. This generally applies to a broad range of situations, from nuclear medicine to nuclear power generation. Some may argue it’s impossible to use nuclear weapons safely. In any case, stringent rules exist to manage nuclear material for good reason.

Sometimes, though, things go wrong, mistakes are made, and that nuclear material ends up going AWOL. That’s the situation that faced authorities in Australia, as they scoured over a thousand kilometers of desert highway for a tiny missing radioactive source with the potential to cause serious harm. Thankfully, authorities were able to track it down.

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Broken Genes And Scrambled Proteins: How Radiation Causes Biological Damage

January 24, 2023 by 31 Comments

If decades of cheesy sci-fi and pop culture have taught us anything, it’s that radiation is a universally bad thing that invariably causes the genetic mutations that gifted us with everything from Godzilla to Blinky the Three-Eyed Fish. There’s a kernel of truth there, of course. One only needs to look at pictures of what happened to Hiroshima survivors or the first responders at Chernobyl to see extreme examples of what radiation can do to living tissues.

But as is usually the case, a closer look at examples a little further away from the extremes can be instructive, and tell us a little more about how radiation, both ionizing and non-ionizing, can cause damage to biochemical structures and processes. Doing so reveals that, while DNA is certainly in the crosshairs for damage by radiation, it’s not the only target — proteins, carbohydrates, and even the lipids that form the membranes within cells are subject to radiation damage, both directly and indirectly. And the mechanisms underlying all of this end up revealing a lot about how life evolved, as well as being interesting in their own right.

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New Study Tells Us Where To Hide When The Nukes Are Coming

January 19, 2023 by 70 Comments

Geopolitics is a funny thing. Decades can go by with little concern, only for old grudges to suddenly boil to the surface and get the sabers a-rattlin’. When those sabers happen to be nuclear weapons, it can be enough to have you mulling the value of a bomb shelter in your own backyard.

Yes, every time the world takes a turn for the worse, we start contemplating what we’d do in the event of a nuclear attack. It’s already common knowledge that stout reinforced concrete buildings offer more protection than other flimsier structures. However, a new study has used computer modelling to highlight the best places to hide within such a building to maximise your chances of survival.

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The Robots Of Fukushima: Going Where No Human Has Gone Before (And Lived)

December 8, 2022 by 9 Comments

The idea of sending robots into conditions that humans would not survive is a very old concept. Robots don’t heed oxygen, food, or any other myriad of human requirements. They can also be treated as disposable, and they can also be radiation hardened, and they can physically fit into small spaces. And if you just happen to be the owner of a nuclear power plant that’s had multiple meltdowns, you need robots. A lot of them. And [Asianometry] has provided an excellent synopsis of the Robots of Fukushima in the video below the break.

Starting with robots developed for the Three Mile Island incident and then Chernobyl, [Asianometry] goes into the technology and even the politics behind getting robots on the scene, and the crossover between robots destined for space and war, and those destined for cleaning up after a meltdown.

The video goes further into the challenges of putting a robot into a high radiation environment. Also interesting is the state of readiness, or rather the lack thereof, that prompted further domestic innovation.

Obviously, cleaning up a melted down reactor requires highly specialized robots. What’s more, robots that worked on one reactor didn’t work on others, creating the need for yet more custom built machines. The video discusses each, and even touches on future robots that will be needed to fully decommission the Fukushima facility.

For another look at some of the early robots put to work, check out the post “The Fukushima Robot Diaries” which we published over a decade ago.

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Detecting Radiation For Fun And Profit

November 9, 2022 by 19 Comments

It used to be that every well-stocked doomsday bunker had a Geiger counter. These days, you don’t have to have a big tube-based meter. You can inexpensively get a compact digital instrument to handle your radiation detection needs. [DiodeGoneWild] reviews and tears down such a unit from FNIRSI. The case looks like several other similar instruments we’ve seen lately, so presumably, someone is mass-producing these handheld meter cases. You can see the video, below. The meter reads the absolute radioactivity and can also measure cumulative exposure.

After measuring a few common radioactive items, we get to the teardown. Inside, of course, is an ordinary tube. A few screws reveal a typical rechargeable battery, a fairly simple PCB with a microcontroller and battery backup for the real-time clock. A lot of the board is involved in multiplying voltage up to the several hundred volts required for the Geiger tube.

The other side of the PCB has only buttons, a vibration motor, and, of course, the LCD. We don’t know how you might test the relative accuracy other than comparing it to a known-good meter. The bare tube was, of course, more sensitive without the plastic cover, but that could be calibrated out, too.

A Geiger counter doesn’t have to have a lot of parts. Either way, a surprising number of things will set them off.

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Dosimetry: Measuring Radiation

November 7, 2022 by 21 Comments

Thanks to stints as an X-ray technician in my early 20s followed by work in various biology labs into my early 40s, I’ve been classified as an “occupationally exposed worker” with regard to ionizing radiation for a lot of my life. And while the jobs I’ve done under that umbrella have been vastly different, they’ve all had some common ground. One is the required annual radiation safety training classes. Since the physics never changed and the regulations rarely did, these sessions would inevitably bore everyone to tears, which was a pity because it always felt like something I should be paying very close attention to, like the safety briefings flight attendants give but everyone ignores.

The other thing in common was the need to keep track of how much radiation my colleagues and I were exposed to. Aside from the obvious health and safety implications for us personally, there were legal and regulatory considerations for the various institutions involved, which explained the ritual of finding your name on a printout and signing off on the dose measured by your dosimeter for the month.

Dosimetry has come a long way since I was actively considered occupationally exposed, and even further from the times when very little was known about the effects of radiation on living tissue. What the early pioneers of radiochemistry learned about the dangers of exposure was hard-won indeed, but gave us the insights needed to develop dosimetric methods and tools that make working with radiation far safer than it ever was.

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Probably The Simplest Radiation Detector You Already Own

September 26, 2022 by 77 Comments

Over the years we’ve featured quite a few radiatioactivity detectors, which usually include a Geiger-Muller tube, or perhaps a large-area photodiode. But in the event of radiation exposure from a nuclear attack, how does the man in the street gauge the exposure without owning a dedicated instrument? This was a question of note at the height of the Cold War, and it’s one that [Dr. Marshall Brucer] answered in a 1962 paper entitled “When Do You Leave A Fallout Shelter“. The full paper is behind a paywall but the part we’re interested in is on the freely available first page.

Dr. Brucer‘s detector is simplicity itself, and it relies on the erosion of a static electric charge by radiation. Should you rub a plastic comb in your hair it will accumulate enough charge to pick up a small piece of paper, and under normal background radiation the charge will ebb away such that it will drop the piece of paper after about 15 seconds. His calculation is that once the field reaches around 10 roentgens per hour it will be enough to erase the charge and drop the paper immediately. There’s a comtemporary newspaper report (Page 7, just to the left of the large advertisment) which tells the reader that since the exposure limit is 100 roentgens (one sievert), this test failing indicates that they have nine hours to create a better shelter. For obvious reasons we can’t test this at the Hackaday bench, but those of us who remember the days when such topics were a real concern will be searching for a handy comb anyway.

Thanks [Victor Matthew] for the tip.