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Monday, March 14, 2011

Very Helpful Radiation Converter

Update: There is going to be a lot of news because today radiation levels in and around Tokyo are going to spike (although not to dangerous levels according to what we now know) and TEPCO reports that it is having problems getting water into the spent fuel pond on Reactor 4 at Daiichi End update.

Reading the news is going to get very confusing. This calculator will help you convert the sieverts and picos into something meaningful.

1 millisievert is a tenth of a rem. You can consider a rem equivalent to a rad for many types of radiation.

You also might need this calculator, which gives you the grays (absorbed doses). Or in table format.

If all that completely confuses you, you might want to start here.

In general, radiation you ingest is a lot more harmful than just exposure. So the type of particle fallout that gets in air and water is very harmful. The fire at number 4 reactor at Daiichi would appear to be the final blow; radiation levels have gone ballistic. A microsievert is a thousandth of a millisievert. Earlier we were getting numbers in microsieverts. Now we are getting numbers in millisieverts. A millisievert is a thousandth of a Sievert. I can no longer type, I swear.

1 milliSievert is supposed to be the max annual nuclear exposure to the public from a nuclear plant. But there are quite a few places in the world where person would get far more than that just from natural radiation. So you certainly have a safety margin. When they say that radiation 400 times the annual legal limit was tested at a plant, they are reporting 400 millisieverts. Usually these reported levels are very short term. Also they drop sharply with distance.

However if you were exposed to 400 millisieverts/h for 20 hours, your net would be 400 X 20 = 8 sieverts. This would not be good because it would be equivalent to 800 rem and you would become very sick and have a good chance of death. 5-8 sievert is considered severe exposure. 1-2 could make you quite ill, even though it is considered "mild" exposure.

So I do not think they can keep workers at Daiichi for very long. Also they are asking everyone for 30 kilometers around to stay indoors.

US residents do not need the duct tape and plastic sheets. If you start to feel nervous, draw the curtains and/or let down the blinds and have sex. It will do far more for your health.

TEPCO says the fire at No 4 reactor at Daiichi is out. They think.

PS: And for the humor only, S&P is considering a possible credit downgrade of Tokyo Electric (TEPCO).

PPS: Mark does the Seattle math.


"US residents do not need the duct tape and plastic sheets. If you start to feel nervous, draw the curtains and/or let down the blinds and have sex. It will do far more for your health."

"Oh yeah, they're really scared."

Radiation did cause me to run a few times in my life. It was an advanced physics class and I had to run silver down the hall to measure its half-life.

The experiment was this one. Time was not on my side!



Ag-108: 2.4 minutes
Ag-110: 24.6 seconds

I was not fast enough apparently. We measured 2.3 minutes and 27 seconds.

I really enjoyed that experiment. The math fascinated me. It was possible to extract two half-lifes with just one set of observations. It's not like we had the ablility to only look at only one of the two decays using a geiger counter.

I wish I could apply that math to our economy. The half-life count seems near infinite though. So many things are decaying at so many different rates. Sigh.
Silver has a 1/2 life? Oh crap, please don't tell my wife, we just got on speaking terms again following my last investment foray.

Poor man's gold... well, no sh*t!

And for the record, this scenario was what I feared when I took exception that there was no US danger. And the distinction between ingested fallout vs. radiation exposure was what I meant in my comment about trans-atlantic flights vs. radio-iodine in my goiter. Hey, it's a big goiter.

One last thing, all the online sources of KI sold-out sometime between Saturday morning and Saturday evening. My problem with panicking is that my procrastination streak is much stronger.
Just saw this. Seemed somehow apropos:



You'll be happy to know that silver isn't radioactive without exposing it to radiation first. That said, when I think of silver I do think of "hot" money these days. ;)
The math really is everything, and a failure to understand it leads people to dumb decisions.

For instance, let's say that you are worried about radio waves from cell towers. You want them further away, right? Wrong, on two counts.

First, if you use a cellphone, you get thousands of times more power from the phone than from the tower. It's the inverse square law--1 cm squared versus (say) 1000 meters squared. That will overcome a huge difference in power levels. And the closer to the tower, the less power your phone will transmit.

If you're worried about the birds, then realize that the cell tower adjusts its power according to how far away the phone is, and the power is still subject to the inverse-square law. The closer the phone, the less power it will transmit.

But an ignorance of physics and math leads people to choose exactly the wrong policies: few towers, far away.

You think it's any better with nuclear power? My grandmother was scared of damaging her microwave oven because it might release "radiation" even when it wasn't plugged in.

She had the excuse of being born before WWII. Most of the cell tower people have half an excuse: their deficient education. But they also have an obligation to educate themselves before advocating for public policy, and only a blessed few do.
MOM, I just wanted to thank you for collecting and filtering the information on this. I really appreciate the time and effort you've spent.
Well, after "sleeping" on it (hey, thanks for the advice MoM), I've decided not to worry about my silver.

As long as it doesn't decay into another element my savings will be OK. This might even be a good thing. Picking up a few extra neutrons should add to the mass, increasing its value.
Dow Jones reporting there is another fire at building 4 and work is under way to put it out.

No more details available at this point.
NHK also mentioning that water level in number 5 spent fuel pool is "lower than usual"

The trend is not their friend.
TEPCO is saying that the latest plume observed may be from reactor 3. They say they cannot confirm the temperature there. They give a count of 514 spent fuel rods in the pool at reactor 3.

At this point, a strategy change is critical.
I mean that TEPCO is saying that smoke may be coming from the suppression pool at reactor 3.

The idea of dumping water via chopper on the Reactor 4 suppression pool, which is on the fourth floor, is not a very good one.

Perhaps they can get boric acid in there. Whether it will help or not is questionable.
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