Jdietz

47 times nothing is still nothing. If there's a biologist in the room I would love to get an opinion on how:

4,700 Bq/kg Cs-137 in soil translates into crop radiation level, and subsequently what added yearly dosage an average human can expect when eating these crops.

Here's a couple of quotes so far I hope to get things back in perspective. Though like I said, I would love to be educated by a nuclear biologist, if you're here, please raise your hand!

One more thing about the radioactive Iodine, if you can store the produce for 80 days, it'll be gone. (10 half-life periods)

temperature in the No. 1 reactor vessel briefly topped 400 C degrees,[/b] requiring large amounts of seawater injected into the reactor to cool it down, according to the agency.

Some sources are not saying anything about " briefly topped " ?

How serious is this if stays at that level ?

Not serious at all, as the pressure in the reactor vessel has been reduced to around atmospheric by venting. The design is for 300C -under pressure- while operating. Steel won't melt until much much higher, not even soften at 400C

You're absolutely right, Iodine levels are a short-term problem, Cesium a long-term.

But let's start with something that has been irritating me for a few days, the '14,000 times normal' etc claims. True as that may be, when dealing with very small (close to zero) numbers, they don't actually mean anything.

Let's take for example electricity, a microvolt is hardly detectable by instruments. You won't feel a thing probing with your tongue. 14,000 times that would be 14millivolt. You will still need a highly sensitive instrument to detect it, and as a human you have no way to differentiate it from the microvolt level.

Now starting at a Volt, you will maybe taste a little sour taste probing with your tongue, or the slightest of tingles. 14,000 times that will be 14kV, and you will basically disintegrate touching that with anything.

So these 'x times something tiny' mean absolutely squat, and is part of the normal scaremongering. What we need is the real numbers -and- the hard part, how much radiation is absorbed short and long term in the human body. This is hard, converting between Bq/Kg and mSv/year for spinach means you need to know what part just 'passes through' the body once, and what part is incorporated long-term.

It is unlikely that veggies will be grown again right outside the reactor site perimeter, but at current levels it is likely that a rainy season followed by a good plowing will be enough a bit further out. Iodine will be undetectable in a couple of months anyways.

I will need to defer the food -> dose conversion to biologists though, it's not just a 'divide by 100' problem.

Edit: one more tidbit: When Iodine (radioactive or not) is absorbed in the body, it concentrates in the thyroid, specifically endangering it. Cesium is distributed fairly uniformly throughout the body's soft tissues, so it doesn't form 'hotspots'

Indeed, the suits are meant to protect you from contamination, not irradiation.

So to tie in with another post, a lead apron doesn't stop gamma rays, you'd need a nice thick wall of lead to make a real difference. Although it needs to be mentioned that most gamma rays pass right through a human body without hitting anything.

Gamma rays can pass through a thin sheet of lead with very little effect. You need about 10 cm of lead to stop most gamma rays completely.

Edit: Here is a nice link explaining types of radiation (alpha, beta, gamma) for the general public: http://www.furryelephant.com/content/radioactivity/alpha-beta-gamma-radiation/

Maybe one of the scientists among us can explain this... The large value 250-300 uSv amounts are listed as a symbol that looks like a "y ray", whereas there are very small values listed separately as "neutron ray" with values of less than 0.01 microsievert per hour.

the y is actually a Greek Gamma.

Source: http://www.gtcceis.anl.gov/guide/rad/index.cfm

Alpha Particles

An alpha particle consists of two protons and two neutrons and is identical to the nucleus of a helium atom. Because of its relatively large mass and charge, an alpha particle produces ions in a very localized area. An alpha particle loses some of its energy each time it produces an ion (its positive charge pulls electrons away from atoms in its path), finally acquiring two electrons from an atom(s) at the end of its path to become a helium atom. An alpha particle has a short range (several centimeters) in air and cannot penetrate a sheet of paper or the outer layer of skin. Alpha particles are a hazard only if they are taken into the body. A number of the radionuclides in sealed sources and other wastes decay by emitting an alpha particle (e.g., Plutonium-238, Plutonium-239, Americium-241, Curium-244).

Beta Particles

A beta particle can be either negative (negatron) or positive (positron). Negatrons are identical to electrons and originate in the nucleus of an atom that undergoes radioactive decay by changing a neutron into a proton. The only difference between a negatron and electron is its ancestry. A beta particle originates in the nucleus whereas an electron is external to the nucleus. Unless otherwise specified, the term "beta particle" generally refers to a negatron, which is the context in which it is used for GTCC LLRW. Beta particles are much smaller and more penetrating than alpha particles, but their range in tissue is still limited. Although lower energy beta particles are generally a hazard only if taken into the body, high energy beta particles represent an external radiation hazard and can produce significant skin doses. Beta particles can pass through a sheet a paper or thin clothing, but are stopped by a thin layer of aluminum foil, plastic, or glass. Many of the radionuclides in GTCC LLRW decay by emitting a beta particle (e.g. Iron-55, Nickel-63, Cesium-137).

Neutrons

A neutron is one of the two primary building blocks of the nucleus, the other being the proton. A neutron has no charge, and high energy neutrons are very penetrating and present an external hazard. Neutrons can be produced by the fissioning or splitting of atoms. Some transuranic atoms such as certain isotopes of plutonium and curium fission spontaneously, i.e., the fission process occurs without the need for additional neutrons to initiate the process. These transuranic radionuclides are present in some GTCC LLRW. Shielding for high energy neutrons generally consists of materials having high concentrations of hydrogen including water, concrete, sheets of paraffin, and plastic.

Gamma Rays

A gamma ray is electromagnetic radiation(similar to visible light, but at a much higher energy in the electromagnetic spectrum) given off by the nucleus of an atom as a means of releasing excess energy, and is oftentimes released when an atom undergoes decay by emitting an alpha or a beta particle. Gamma rays are bundles (quanta) of energy that have no charge or mass and can travel long distances through air (up to several hundred meters), body tissue, and other materials. A gamma ray isextremely penetrating and represents an external hazard. A gamma ray can pass through a human body without hitting anything, or it may hit an atom and give that atom all or part of its energy. Because a gamma ray is pure energy, it no longer exists once it loses all of its energy. Some GTCC LLRW has very high concentrations of radionuclides that emit high energy gamma rays, such as cesium-137. These wastes must be remotely handled or adequately shielded to protect workers. Thick layers of concrete, lead, steel and other comparable shielding materials are necessary to stop the penetration of gamma rays.

X-Rays

An X-ray is the same as a gamma ray, but originates external to the atom by the movement of electrons between energy shells (from a higher to lower energy shell). The excess energy associated with thiselectron movement is released as an X-ray. X-rays have less energy than gamma rays, are less penetrating, and require less shielding. In all other aspects, X-rays behave in the same manner as gamma rays.

Here you see someone refilling the model storage pool I talked about earlier (bad jpg screen grab)

It's like a Papal election in the Vatican.

White smoke is good

Black smoke is bad

In other news, Americans are advised to go home, lock the doors and watch Fox News.

OK enough US bashing for now

JF: The graph you've posted earlier is now updated and shows the same peak (albeit attenuated) I talked about in the SPEEDI data:

http://mextrad.blob.core.windows.net/page/08_Ibaraki_en.html

http://www.bousai.ne.jp/eng/

SPEEDI still reports 1.153 microSievert/h @ Ibaraki

BTW the Japanese really like their models, right now they are showing some very pretty reactor mock-ups complete with little storage pools you can fill with water. Somebody must have put in some overtime into those..

I'm waiting on the first anime.

We will know more as soon as they get some instrumentation back up in the control room. Right now it's all observation / reaction in reactors #1 to #4. Pressure and temperature gauges don't need power, but that's mostly it.

- There is steam, there must be water

- Pressure is rising, let's vent some air

- Temperature is rising, let's add some water

Nobody really wants to take the lid off and have a good look at this stage.

Don't forget it may be just the wind direction change and rain. Doubling/halving at this level (delta of half a microSievert) doesn't really mean much, order or magnitude changes do.

The monitors are situated at nuclear plants, they don't really build those inside big cities for now obvious reasons. If you hover your mouse over the measure points it mentions the location of the detectors.

Re: the elevated radiation levels:

It is indeed raining, and the wind is quite strong NE according to Google

Weather for Ibaraki Prefecture, Japan

7°C | °F

Current: Rain

Wind: NE at 21 km/h

Humidity: 92%

But the site you're looking at seems to show dozens of different readings from Ibaraki prefecture, some low... some up to 1+ microsievert per hour.

SPEEDI http://www.bousai.ne.jp/eng/ is a live interactive map of the whole of Japan, explains the different readings It is updating its readings several times an hour (I think every 10 minutes) from its monitoring stations, sites 'under survey' are down (not surprisingly as there is no power at Daiichi)

NKH world reporting higher radiation levels due to change in wind and weather, confirming SPEEDI observation.

Excerpted Monday Updates from Daily Yomiuri

http://www.yomiuri.co.jp/dy/

TEPCO said the number of its workers whose radiation exposure exceeded 100 sieverts increased to seven from six as of 5 a.m. Sunday. The government had raised the upper limit of the radiation exposure for workers at the Fukushima plant from the ordinary 100 sieverts to 250 sieverts as an exceptional measure.

They mean milliSievert, everything over 7 Sievert or so is quite deadly, 100 would mean instant incineration.

Good morning everyone.

I just noticed the Ibaraki radiation level according to SPEEDI http://www.bousai.ne.jp/eng/ doubled overnight to 1151nGy/h (1.1 microSievert/h). Is it raining? Levels have been falling steadily over the last 4 days, but now they're back to the point of around the 17th.

No, you'll have to do that in Bangkok. See here.

http://www.netherlan...t_in_Chiang_Mai

Nederlands consulaat in Chiang Mai

Bent u woonachtig in het noorden van Thailand dan kunt u zich ook wenden tot het Honorair Consulaat in Chiang Mai

Openingstijden

iedere maandag, woensdag en vrijdag van 09.00 - 12.00 uur

Paspoortuitgifte

Nee

Uitgifte Nederlandse identiteitskaart

Nee

Hoofdpost

Ambassade Bangkok

Honorair Consul

Dhr. Peter van Loo

Here, have some comma's, full stops and capitals, they may make your rant readable.

...,,,III

The sea can be used as a heat sink, not the same as pumping seawater directly in the reactor core.

More on Japan reactor setback: Radioactive gas will be released to ease pressure/RT@BreakingNews

This is worrying. Last time they vented unit 3, the building exploded soon after....... Let's hope they do it slowly so any hydrogen has chance to disperse.

Nothing much left to explode in #3, outside 'structure' is all but gone, Hydrogen won't have a problem to escape that pile of rubble, even if it ignites.

True at the top of the building..... But bear in mind that the plant is partly underground. And they were considering venting the reactor into the pressure suppression pool. Which is the toroid structure at the bottom. An explosion down there could potentially send the core shooting up into the air like a rocket

Suppression pool is made exactly for that: emergency venting, it has no use during normal reactor operation. Instead of venting to atmosphere, you vent through water, forcing water out the overflow. This way you trap more radioactive isotopes compared to venting directly.

Venting directly through the top escape valve of the reactor is the back-up scenario, when there are troubles with the suppression pool. This will directly release radioactive isotopes in the atmosphere, and increase levels around the plant more, so first option is preferred.

Pool is inside the wetwall, but outside the drywall, containing the steel reactor vat.

More on Japan reactor setback: Radioactive gas will be released to ease pressure/RT@BreakingNews

This is worrying. Last time they vented unit 3, the building exploded soon after....... Let's hope they do it slowly so any hydrogen has chance to disperse.

Nothing much left to explode in #3, outside 'structure' is all but gone, Hydrogen won't have a problem to escape that pile of rubble, even if it ignites.

I don't think it has come up today but the readings at http://www.bousai.ne.jp/eng/ seem to be lower across the board again, with Ibaraki now at 650nGy/h (0.65 microsievert/h), down from about 750/850/950 last three days.