Juan de Fuca
Emergency Management

South coast of Vancouver Island
BC, Canada
JDFEM.com
Radiation
Stephen Holland softwaves.net
What is Radiation?
Understanding Units
EXTERNAL RADIATION
Reference Charts to compare Units, Rates and Dose, and analyze news stories
Demo - Analyzing a typical news story
Acute Radiation Sydrome
INTERNAL Radiation and Fallout
The Big Three and decay patterns
Iodine 131 and Half-life-- scary in the short term
Some short-term solution for a city water supply
Cesium 137 ---- Strontium 90 -- the bigger worry in the long term
Other major reactor accidents - - a comparison chart
Background Radiation Radon in your basement?

The public needs Information

A company or government will be criticized for mistakes, but usually quickly forgiven if it acknowledges the mistakes. However if it comes out later (days, years) that bad news was hidden from the public, the public is much less forgiving. Honesty and transparency always leaves the best long-term legacy.

And it is hoped that reporters hearing the news given out by company or government spokesmen will read this and dig for meaningful information and comparisons.

For example, External and Internal radiation should be treated very differently. The body can handle a fair amount of external radiation, which can send Geiger counters soaring, yet very small amounts of Iodine, Strontium or Cesium in the body can produce cancer.

Also, the public wants to know how current and future disasters compare with past ones. At the bottom of this page are numerous comparisons between disasters, even comparing with the Hiroshima A-bomb.


What is Radiation?


Understanding Units


EXTERNAL Radiation
External radiation is easy to monitor and control. A simple Geiger Counter tells how much you are getting, and you can just walk away, or put on protective clothing (or lead aprons for dental X-rays).



Demo -- How to analyze a typical news story

RATE x Time = DOSE

On Thursday, you volunteer to work 8 hours between Reactors #2 and #3. 30 mSv/hr x 8 hours = DOSE = 240 mSv

The dose on Thursday of 240 mSv was about double a whole-body scan, and may likely give you some mild radiation symptoms like fever, headaches, nausea.

On Friday you feel a bit odd in the morning, but volunteer to work another 8 hours in the wreckage of Reactor #3 to fix an important water pump 400mSv/hr x 8 hours = DOSE of 3200 mSv = 3.2 Sv

By Friday night, you have absorbed 240 + 3200 = total dose = 3440 mSv Any dose over 1000 mSv, or 1 Sv, might give you Acute Radiation Syndrome. Based on the symptoms chart below, with over 3 Sv of dose, you may have a 50% chance of dying in 4-6 weeks.


Acute Radiation Syndrome
The total dose of 3440 mSv in the above example is extremely high, bringing on the "Acute Radiation Syndrome" There woud be about a 20-50% chance of dying within a few weeks and it's not a nice way to die. This is a chart from Wiki for symptoms of extreme exposure, typical only of people near A-bomb, or during major accidental exposure at nuclear reactors (click to enlarge)


INTERNAL radiation and "Fallout"
Internal radiation is much more complicated. The radioactive products get in the body and may stay for years. They are very difficult to monitor and to control. We can't stop the "falling out" except monitor weather patterns. We can only try to minimize the radioactive isotopes from getting into the food chain and people.

Also, fallout radiation can have massive effects economically as agricultural land and towns can be declared off limit for production, habitation and tourism, and exports are curtailed. A vibrant city and agricultural area may turn into a forest. But often the FEAR factor does more harm economically and psychologically than the radiation danger.


Fision Products (broken halves of the uranium nucleus)
Very radioactive "waste" including Iodine, Cesium, Strontium, and many others.This is what makes old fuel rods so dangerous for centuries.
When carried by smoke or wind, it can land on soil and be taken into plants, then animals or it can land on water and be taken up by fish or get into drinkng water systems.

Biomagnification in the Food Chain
This chart is made from DDT data from Silent Spring by Rachel Carson, the book that launched the Environmental Movement in 1963. Numbers will vary for different situations, animals and chemicals, but the principle is valid.

Like DDT, radioactive fallout concentrates as it goes up each level of consumption in the food chain.

In other words, people who eat lots of animal products (beef, fish, chicken, eggs, cheese) would get much higher doses than pure vegetarians ("Vegans").

A kg of meat or milk or fish may have many times the radiation of a kg of bread.





Farm animals like beef, pork, sheep, goats and chickens which eat vegetation are much better than fish which are higher in the food chain.


Iodine Fallout in the US from nuclear tests in Nevada
Fallout of radioactive Iodine from Nevada Atom Bomb tests

This shows how fallout tends to fall in patterns. Heavy materials like cesium will fall closer, whereas Iodine as a vapour can carry long distances.

More maps on fallout patterns are on Nuclear Files.

Worries about fallout stopped the above- ground tests of A-bombs. But we can learn from that experience how to cope with fallout from nuclear reactor accidents.


The Big Three - decay patterns
Uranium nuclei split into two parts during fission. Three isotope products -- Iodine 131, Strontium 90, and Cesium 137 -- are most important for fallout danger, based on experience with Chernobyl and A-bombs.

Iodine-131 --- WIKI ------------ I-134 has a half-life of 52 minutes "Due to its mode of beta decay, iodine-131 is notable for causing mutation and death in cells within 2 mm. It accumulates in the thyroid gland in the neck...and can cause Thyroid cancer."
Iodine supplements saturate the thyroid with non-radioactive iodine

Cesium-137 --- WIKI ------------ Ce-134 has a half-life of 2 years "Together with caesium-134, iodine-131, and strontium-90, Ce-137 was among the isotopes with greatest health impact distributed by the Chernobyl reactor explosion.
"Caesium-137 is biologically similar to that potassium.
After entering the body, caesium gets more or less uniformly distributed through the body, with higher concentration in muscle tissues and lower in bones. "The biological half-life of caesium is rather short at about 70 days" (time the body flushes out half of it).

Strontium-90 --- WIKI --- "it was among the most important isotopes regarding health impacts after the Chernobyl disaster.

Strontium-90 is a "bone seeker" that exhibits biochemical behavior similar to calcium.
After entering the organism, most often by ingestion with contaminated food or water, about 70-80% of the dose gets excreted. Virtually all remaining strontium-90 is deposited in bones and bone marrow, with the remaining 1% remaining in blood and soft tissues. Its presence in bones can cause bone cancer, cancer of nearby tissues, and leukemia."


HALF-LIFE -- How long to worry

Iodine -- Bad in the short term
Half-life
If you have 1 kg of radioactive material, in the time of one "half-life" half of the radioactive atoms will decay, leaving only 500 grams, and in another "half-life" you have 250 grams, and in another "half-life" you will have 125 grams, so on.

Cesium and Strontium -- Bad in the long-term

Strontium and Cesium follow the same rule as Iodine, losing half their radioactivity during their "half-life", but have a half-life around 30 years instead of 8 days. They will have a much longer and more important impact than Iodine.

This graph shows proportion of each element in the long-term after the Chernobyl disaster in 1986.

Iodine with a half-life only 8 days quickly fades to low importance, while Cesium with a half-life of 30 years becomes the dominant radioactive problem.
This does not show how much they radiate, which will be decreasing, only the importance of cesium for long-term planning.

Basically....
Iodine is a short-term problem, big in the news and for children, but fading over weeks.

Cesium is a long-term problem affecting future generations, agriculture, industry, exports, tourism, etc.


Major reactor accidents
before Japan
Chernobyl disaster on 26 April 1986 in Ukraine. Poor design and operating mistakes led to the reactor having a steam explosion and catching fire. The reactor was a mix of uranium and graphite, and had no modern containment vessel. The graphite reactor core burned like a bonfire spreading tons of radioactive smoke and material around Europe and beyond.
Kyshtym disaster in 1957, where containers of radioactive waste overheated and had a chemical explosion, releasing a cloud over a long, narrow area
Windscale fire in 1957 at a reactor in England. It was an early graphite reactor that had design problems, plus the science of reactors was still being invented. It caught fire, letting out radioactivity in the smoke.

Three-Mile Island meltdown accident in 1979 in Pennsylvania had a serious meltdown of the reactor core, due to control and training problems, but little escaped the containment vessel except Xenon.

Release of Radioactivity

This is a chart to compare the radioactivity released in past important disasters for comparison.
The data comes from WIKI.

JDFEM.com -- Juan de Fuca Emergency Management resource


Sources of Background Radiation
for an average person

About half comes from natural sources. The other half comes from manmade sources.
Any one of these radiation sources, as well as the non-radiation causes like
chemicals, heredity, smoking, sun tans, and other factors could lead to cancer

RADON
Radon is a natural gas given off by soil and rocks, and tends to accumulate in basements and houses, especially with little ventilation in winter. Radon is considered the second leading cause of lung cancer.
See Health Canada Page 2, Page 2and video

What if you had no X-rays?
Radon gas becomes even more important for your exposure to background radiation

JDFEM.com
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