Gamma rays from Fukushima rubble worse than radioactive cesium coming from plant, say officials

TEPCO admitted unit 2 is spewing 8 million bq/hour on July 24th. Did they suddenly solve all the problems at the plant? That number seems impossible, to only have .1 bq/hour leaving the plant now.

Seems a little misleading, Gammer rays are interfering with the clean up? To a higher degree than the radiation? Is that the point? Is this a glass half full good news story?

There must be a mistake here. 0.01 becquerels per hour is too small to be measured. Maybe they mean 0.01 billion becquerels per hour?

In Shinichi Kuroki's world some mysterious natural phenomenal must have contaminated all the rubble with something (not cesium) that emits gamma rays... way to go Shinichi Kuroki :) He probably never heard of Fukushima or radiation before, got some numbers on his desk and even managed to misread them.

As many suggested, the release of the plant should still be 10million bq/h or more.

Error or not the US nuclear industry has been running this as proof nothing is wrong at all in Fukushima. :( You can't have 8-10 million bq/hour AND .1 bq/hour at one plant. Unless TEPCO has invented the miracle radiation sucking machine..

CrickyAug. 28, 2012 - 09:04AM JST

Seems a little misleading, Gammer rays are interfering with the clean up? To a higher degree than the radiation?

Gamma rays ARE radiation, as are high energy beta particles. The difference is in how they affect the human body. Beta particles are stopped at the skin or never get there if there's even a thin sheet of metal, while gamma rays can go through your body and several cm of lead as well. Unless ingested beta particles pose little long term problems, no more than a similar amount in UV light. However, gamma rays bypass your skin and can strike anywhere, and as such pose a higher long term issue from external exposure.

ScroteAug. 28, 2012 - 09:16AM JST

There must be a mistake here. 0.01 becquerels per hour is too small to be measured. Maybe they mean 0.01 billion becquerels per hour?

If you increase your sample time you can measure the smallest of amounts as long as the electrical noise levels allow. It is regularly used to determine if wine is actually older than 70 years or not, as older wine will not have any Cs137 while 70 year old wine will have less than 1mBq. It can take days to read the mBq range, so perhaps a few hours for 0.01Bq.

Nancy FoustAug. 28, 2012 - 10:47AM JST

You can't have 8-10 million bq/hour AND .1 bq/hour at one plant.

That's like saying you can't overfill a cup without your neighbor's floor getting flooded. The 8-10 million figure is at the reactor, 0.01 figure is at the plant boundary. This means 99.9999999999% of the radiation is contained within the nuclear plant site, and likely 99.999% is within the reactor building itself.

In fact:

the combined external and internal radiation exposure level at the main gate of the plant facility about one kilometer from the nuclear plant was 0.02 millisievert over the course of a year.

This extra radiation represents a 1-2% increase over background radiation, and falls in line with the new readings.

Steve it's a news release not an investigative news article, PR at best. You will get used to it in a country that has a media who relies on being in a club to earn their wage.

IAEA chief Yukiya Amano urged delegates to maintain their “sense of urgency” on post-Fukushima nuclear safety.

Unfortunately, the urgency and priority for the nuke companies, corrupt politicians, the nuke village and cheer-leaders seems to be how quickly they can lie Japanese to restart as more nuke plants as possible. This year's unusually hot summer months let them down the other day, when it was clear Japan can after all function even during the summer without nuke electricity! Once sold and accepted as safe and clean, the silent killer nuke electricity has instead proven to be environmentally suicidal, inconveniencing, dirty, expensive, unsustainable and unethical.

Basroil said

If you increase your sample time you can measure the smallest of amounts as long as the electrical noise levels allow. It is regularly used to determine if wine is actually older than 70 years or not, as older wine will not have any Cs137 while 70 year old wine will have less than 1mBq. It can take days to read the mBq range, so perhaps a few hours for 0.01Bq.

It's true that levels in the mBq range can be measured, but these measurements are made in underground laboratories shielded with lead and water. Even then, the sensitivity of such measurements is a few mBq/litre of wine, not 1 mBq. Such measurements cannot be made outdoors, where the reactors are, and where the background radiation level is far higher than 0.01 Bq/hour. Hence, the figure of 0.01 becquerels per hour makes no sense.

Um... Just a quick correction here. Your skin does not stop beta radiation. You need a thin strip of metal to do that. Yes, it doesn't damage as much as gamma, but it does still hurt.

Gamma radiation is of a very high energy, the most damaging to living organisms. You don't want to be near it when it's coming from a 'constant' source. You need lead, thick concrete etc to stop it. The others, alpha and beta you can use paper and foil respectively to shiled, they do the damage when consumed, internal emitters.

You Maniacs! You blew it up! Ah, damn you! God damn you all to hell!

@Nancy Foust

TEPCO admitted unit 2 is spewing 8 million bq/hour on July 24th. Did they suddenly solve all the problems at the plant? That number seems impossible, to only have .1 bq/hour leaving the plant now.

Don't worry, @Nancy. Nothing serious, they've just misplaced a decimal point again! Nothing to get excited about, move along now!

The PR machine just continues randomly reporting numbers, out of context and round it off with "no immediate risk to health", and Bob's your uncle! Sorted! This media lark's a piece of cake, when it's a private club.

Weasel

The Prussian Blue coming into Japan via Heyl Chemisch-pharmazeutische Fabrik GmbH & Co, is distributed by Nihon Medi-Physics and it all goes to J Govt for J Govt. Stock piling Prussian Blue for themselves since it costs $100 US per 30 grams. Heyl is the only company who produces Prussian Blue to my knowledge.

Read more about Prussian Blue on this link:

http://www.japantoday.com/category/commentary/view/fukushimas-cesium-spew-deadly-catch-22s

blackbaggerAug. 28, 2012 - 12:31PM JST

Um... Just a quick correction here. Your skin does not stop beta radiation. You need a thin strip of metal to do that. Yes, it doesn't damage as much as gamma, but it does still hurt.

As with most things in life, you are correct only depending on your assumptions. Lowest energy beta can be stopped by as little 6 micrometers of soft tissue, while the very high energy ones will go several cm in addition to releasing gamma. In this case however, we are discussing energy from Cesium, both 134 and 137 which are a significant issue compared to other isotopes. A little less than 5% of the total radiation energy is released above 600keV, and the maximum is 1.3MeV (Cs134, most of the high energy peaks at 1.1MeV from Cs137). At 1.3MeV, there is a maximum of about 5mm of soft tissue penetration and will allow a small portion of energy to go past even the thickest parts of skin.

However, at the average energy level, you can expect about 1mm of penetration, which will be stopped by all but your eyelids. As such, the gamma is far more damaging, especially when considering many people will have layers of clothing to further minimize beta absorption but have practically no effect on gamma.

ScroteAug. 28, 2012 - 12:29PM JST

It's true that levels in the mBq range can be measured, but these measurements are made in underground laboratories shielded with lead and water. Even then, the sensitivity of such measurements is a few mBq/litre of wine, not 1 mBq. Such measurements cannot be made outdoors, where the reactors are, and where the background radiation level is far higher than 0.01 Bq/hour. Hence, the figure of 0.01 becquerels per hour makes no sense.

I used wine as an example, but there are some differences. The main being that in the case of wines, you must measure gamma radiation rather than beta, as glass can stop even the highest energy beta from Cs137 within two mm. It's that many opt for geiger counters due to that, and lose the ability to measure the type of radiation, but some might stick with scintillators to double check. On top of external cesium contamination, non-cesium sources of gamma rays would also interfere and likely mask any possible measurements.

However, you do bring up a good point that it is almost impossible to actually measure that level in the field due to background contamination. The instruments would likely need to detect Cs137/134 to nearly a dozen decimal places in some cases, as well as account for both decay and particle motions (wind, rain, trucks picking up dust, etc) that are likely orders of magnitude larger. In areas that are already 1 MBq, you would have about 2.6Bq/hr lower rate each hour (bit more complicated) from decay of the material alone, which is much larger than the number. The number given is likely not a measurement as much as an estimate from relative measurements taken before. In fact, the article never states it was measured, so we should assume it was estimated.

Rest assured that the immediate plant environment --and its surrounding locality, including the seabed-- are NOT 'only' contaminated with the contaminants some are mentioning to pacify the reality. Every isotope produced by fission, other than those with a short half-life, will be present. Gamma radiation --as this article, which is TEPCO sourced, clearly explains in simpe / accessible English-- is a bigger problem than the cesium still being emitted from the crippled nuclear plant... That, even to the layman, should strike a sense of understanding.

Gamma Rays? O.o

I thought they were the stuff of science fiction?

YongYangAug. 28, 2012 - 12:42PM JST

Gamma radiation is of a very high energy, the most damaging to living organisms.

Actually alpha radiation is most dangerous to most living organisms (bacteria make up most of the biological mass of the earth) due to much higher kinetic energy dissipation. Gamma radiation, unlike beta radiation, cannot be contained by simple means, and is more dangerous to workers. On the other end of the spectrum are alpha emitters like heavy elements that found in reactors, which all isotopes of significant production above Radon are, including all trans-uranium metals.

All alpha emitters released by Fukushima amount to a few dozen grams. Alpha radiation is entirely harmless to workers unless ingested in significant quantities. As they are heavy metals with no biological functions and pathways, workers could eat several hundred milligrams of the alpha emitter mixture without increasing cancer risk above a level that is statistically significant. The workers and public have nothing to worry about from alpha emitters.

Beta and Gamma emitters are the significant risk, especially gamma radiation for workers in already high risk jobs.

Cesium seems to be the only thing the government and TEPCO know about. Packs of useless morons.

@Basroil

Do you know what are the alpha emitters at Fukushima? Because for certain of them a "few dozen of grams" is not a trivial thing at all.

zichiAug. 28, 2012 - 04:40PM JST

Several hotspots of plutonium have been found around the plant.

What do you mean by "around the plant?" Immediate environs? Farther afield?

Forget that last post Zichi, followed your later link. Obviously follow-up work is needed on Pu contamination.

Open MindedAug. 28, 2012 - 09:20PM JST

Do you know what are the alpha emitters at Fukushima? Because for certain of them a "few dozen of grams" is not a trivial thing at all.

Total radioactive release is in the magnitude of 10TBq, most of it from Pu241 and other similarly short lived transuranium isotopes. Most of the mass however is in long lived isotopes, where a vast majority of that is >6000 years half life, which have activities ten (or more, most Pu present is over a hundred times smaller) times lower than Pu241 which accounts for less than a gram. Not including the more active Pu241, the remaining isotopes added together amount to several GBq, which is on the same order of magnitude as polonium released into the air each year by cigarettes in Japan. As mentioned before, this is not harmful unless internally administered, and due to the fact most of these metals tend to clump, it is very easy to filter them out. A few dozen grams also covers all Cs137 released into land outside the plant, but as you mentioned it is far less trivial than alpha emitters, and itself eclipsed by gamma emissions .

With all this talk of gamma rays I am wondering if we will soon see the Incredible HULK!