Archive for Tchernobyl

Decontamination After Radiation Exposure: Simpler Than You May Think

Posted in 2020, Health with tags , , , , on April 21, 2020 by theboldcorsicanflame

 

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https://www.npr.org/sections/health-shots/2011/03/17/134627643/decontamination-after-radiation-exposure-simpler-than-you-may-think?t=1587310914375

A boy evacuated from Koriyama, some 37 miles from the Fukushima Dai-ichi plant, gets scanned with a Geiger counter Wednesday.

Ken Shimizu/AFP/Getty Images

The Japanese government says 20 workers at the disabled Fukushima Dai-ichi power plant have been decontaminated after exposure to radioactive material.

Dozens more, at least, have reportedly been decontaminated within the 12-mile evacuation zone around the plant after Geiger counters picked up evidence of radiation exposure.

That made us wonder just how someone gets decontaminated from radiation – which, after all, is invisible, odorless, tasteless and generally insidious. Most people think of it as “rays,” which is partially correct.

The answer might surprise you.

“Decontamination is very simple,” says Dr. Eric Toner of the University of Pittsburgh’s Center for Biosecurity, who has studied what might happen in the wake of a terrorist’s “dirty bomb” attack.

“As a rule of thumb, 80 percent of decontamination is removing your clothes,” says Toner, an emergency physician. “And 95 percent is removing your clothes and taking a shower — if possible, shampooing your hair. That’s all that’s involved. No fancy chemicals.”

That’s because radiation is carried on dust particles. “The air isn’t radioactive, but small dust particles are,” Toner explains. “You’re essentially washing off the dust.”

So a rain is a good thing at the time of, or after, a radiation leak. Rain washes the dust from the air, diluting it in runoff. (Yes, the runoff would be radioactive, but diluted — and presumably, the ground would also be getting radiation exposure already.)

Dry air, when dust gets kicked up in the air and disbursed over longer distances, is bad.

By the way, the dusty clothes can often be decontaminated simply by washing them, but it depends on the amount of radiation detected. “If you have reason to think they’re heavily contaminated, they should be disposed of properly,” Toner says. That means put in a plastic bag and, if possible, taking them to authorities for disposal.

All this raises another question – how to decide if somebody needs to be decontaminated.

At a place like the Fukushima power plant, where workers wear dosimeters that constantly record exposure and the environment is being continually monitored for radioactivity levels, the decision is clear-cut.

But it’s far less so out among the general public. In a situation like the current one, there’s a profound lack of information on radiation levels at different distances from the power plant and how they might be fluctuating over time.

In an emergency room or post-disaster setting, Toner says doctors would usually use a Geiger counter to screen people – before decontamination, to see if they’ve had any detectable exposure to start with, and afterward, to see if they still have traces of radioactive dust.

There is a lot of Geiger-countering going on in northern Japan right now – as most TV-watchers know by now. But using Geiger counter readings, given in “counts-per-minute,” or cpm, is not necessarily a great way to know if you need decontamination. Or whether it’s time to start taking potassium iodide pills to protect against thyroid cancer.

Steve Herman knows about that. He’s a correspondent for Voice of America who got a Geiger counter scan Thursday in Koriyama, a town 37 miles from the Fukushima Dai-ichi plant as the crow flies.

“My body 1,500 cpm, my boots 3,000 cpm. Another reporter: 10,000 cpm on her shoes,” Herman tweeted.

What to make of those readings? It’s hard to know.

“It is really hard to interpret Geiger counter cpm’s,” Toner says. “They vary from machine to machine. For example, they depend on the size of the probe – the bigger the probe, the more counts detected. And each machine must be calibrated against a known source (of radiation). Translating the cpm’s to an actual exposure does take a health physicist.”

In addition, Geiger counter readings don’t tell you a thing about the type of radiation a person may be exposed to – whether it’s a fairly weak and short-lived isotope that doesn’t pose a health risk, a form of radioactive iodine that signals the need to take protective tablets, or a more sinister isotope, such as cesium-137, that can raise long-term health risks if it gets inside the body.

And this is the most worrisome form of contamination – internal contamination. The bad stuff on skin and clothes is easily washed off. But once radiactice particles get inside the body – through breathing in, but more importantly from ingestion – it can remain in tissues, possibly wreaking submicroscopic havoc, for a lifetime.

That’s why Thursday, Japanese authorities activated provisions of its Food Sanitation Act, which allows the government to test food for radioactive contamination and pull it from the market.

Experts say it was the Soviet Union’s failure to do that, for many weeks after the 1986 Chernobyl power plant disaster, that caused most of the health consequences – which continue to this day

 

 

 

NUCLEAR ENERGY: RADIATION VS. CONTAMINATION

Posted in 2020, Health with tags , , , , on April 16, 2020 by theboldcorsicanflame

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Pripyat in Ukraine had to be abandoned after the Chernobyl accident due to the high amount of radioactive contamination

A common misconception is the idea that exposure to radiation in turn makes someone radioactive. This is, usually, not the case. It’s important, then, to understand the differences between radiation, and radioactivity.

WHAT DOES IT MEAN TO BE RADIOACTIVE?

An atom is said to be “radioactive” if it is unstable due the excess of either energy or mass, and is therefore likely to decay at some point and give off radiation. A substance or material is said to be “radioactive” if it is made up of or contains a large quantity of a radioactive material. These radioactive materials, such as bananas, the uranium glaze in vintage fiestaware, or NORM generated in the process of natural gas exploration, give off radiation over time as the radioactive atoms in them decay.

Uranium Ore, a naturally radioactive substance
Uranium Ore, a naturally radioactive substance

Over time, as the number of unstable atoms decreases, the material becomes less radioactive. This time is measured by the “half life” of different radioactive elements. This is the amount of time it takes for half of the atoms in a given sample to decay and give off radiation. For example, carbon-14 has a half-life of 5730 years, so after that amount of time, a quantity of 100 atoms of C-14 would have turned into 50 C-14 atoms and 50 Nitrogen-14 atoms. Iridium-11, a radioactive isotope used in medicine as a tracer, has a half-life of 2.8 hours; whereas another isotope of iridium at the other end of the scale, iridium-115 has a half-life of 441 trillion years. It’s commonly held that a sample of radioactive material will be completely decayed after 7 half lives, though after that time there would still be about 0.78% left, which with a large enough starting sample would still be significant. For smaller samples like those typically used in medicine, though, it’s a good rule of thumb.

WHAT IS CONTAMINATION?

Put simply, radioactive contamination is just radioactive material somewhere it shouldn’t be. This could be anything from nuclear fallout from a dirty bomb (the whole purpose of which would be to disperse radioactive contaminant), to a lab worker splashing some of a radioactive solution on his pants and taking them home. The most common source of contamination is from mistakes or accidents in the production of radionuclides, like those used in the medical field.

Pripyat in Ukraine had to be abandoned after the Chernobyl accident due to the high amount of radioactive contamination
Pripyat in Ukraine had to be abandoned after the Chernobyl accident due to the high amount of radioactive contamination

Contamination on or in a surface can be either “fixed” or “removable.” An example of fixed contamination, or contamination that isn’t able to be removed, would be in metal recycling: If a batch of recycled metal included something with radioactive material in it, the final product would have that radioactive material mixed in and permanently part of it. Removable contamination is, of course, removable, such as a loose powder or something that can be cleaned and safely disposed of. Disposal of radioactive waste can consist of reprocessing it for commercial use, though in some cases where this isn’t possible the best solution is burying it in concrete, rock, as this helps prevent the spread of the contamination any further.

DOES BEING EXPOSED TO RADIATION MAKE ME RADIOACTIVE?

Exposure to radiation does not immediately make a person radioactive. The only type of radiation that is capable of directly causing other material to become radioactive is neutron radiation, which is generally only found inside nuclear reactors or in a nuclear detonation. Anyone in those conditions is, put plainly, going to have bigger problems.

CT Scans and other routine medical procedures expose someone to radiation without leaving that person radioactive afterward
CT Scans and other routine medical procedures expose someone to radiation without leaving that person radioactive afterward

However, the ingestion of radioactive material does have the potential of making a person radioactive, at least on a temporary basis. This is the principle behind the medical use of many radioactive materials, as it aids in imaging, diagnosis, and other areas. Between the short half-lives of the elements involved and the body’s natural means of disposing of many radioactive elements, a person’s individual radioactivity is usually short-lived. However, certain types of contamination, depending on the isotopes involved and the availability of treatment, can become more permanently deposited in a person’s organs or bones.

 

TO BE CONTINUED ON

https://www.mirion.com/learning-center/radiation-safety-basics/radiation-vs-contamination

March 16th 2011: 508 Replicas since the Magnitude 9. Earthquake, Today A 5.8 Earthquake – Fukushima Out of control !

Posted in Uncategorized with tags , , , , , , , , , , , on March 16, 2011 by theboldcorsicanflame


Unprecedented disaster tests resilience of society BY KEIJI TAKEUCHI

READ FULL ARTICLE ON
http://www.asahi.com/english/TKY201103150148.html

EXCERPT
Extremely serious levels of radiation have escaped. Dangerously high doses of radiation have been detected in or near the compounds of the quake-hit Fukushima No. 1 nuclear power plant in Fukushima Prefecture.

Japan’s worsening nuclear crisis will now be compared to the Chernobyl disaster in the former Soviet Union in 1986.

The Fukushima plant has six reactors. Of them, the No. 2 reactor has begun to release radioactive substances as the suppression pool connected to the reactor containment vessel was apparently damaged.

The No. 1 and No. 3 reactors are also in a perilous situation with their nuclear fuel rods exposed out of cooling water.

An apparent hydrogen explosion has rattled the No. 4 reactor, whose operation had been suspended for inspection when the magnitude-9 earthquake struck March 11. Spent nuclear fuel rods kept in a pool with circulating water appear to have produced hydrogen. If they are exposed above water, then the dangers from the extremely strong radiation would hamper work to bring the situation under control.

Now, four nuclear reactors standing in a line are simultaneously spinning out of control.

Unprecedented disaster tests resilience of society BY KEIJI TAKEUCHI

TO BE CONTINUED ON
http://www.asahi.com/english/TKY201103150148.htm

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