A radiation monitor at the troubled Fukushima Daiichi nuclear power plant says workers there are exposed to immeasurable levels of radiation.

The monitor told NHK that no one can enter the plant’s No. 1 through 3 reactor buildings because radiation levels are so high that monitoring devices have been rendered useless. He said even levels outside the buildings exceed 100 millisieverts in some places.

Pools and streams of water contaminated by high-level radiation are being found throughout the facility.

The monitor said he takes measurements as soon as he finds water, because he can’t determine whether it’s contaminated just by looking at it. He said he’s very worried about the safety of workers there.

Contaminated water and efforts to remove it have been hampering much-needed work to cool the reactors.

The monitor expressed frustration, likening the situation to looking up a mountain that one has to climb, without having taken a step up.

Tuesday, April 05, 2011 19:51 +0900 (JST)

http://www3.nhk.or.jp/daily/english/05_38.html

–bks

So to prevent criticality you need ~ one atom of natural boron per atom of fissile material. If there are 100 tons of uranium at 1% fissile material, you have ~ 1000 kg of fissile material, or about 1000/235 kg/mole = 4.25 kg-mole. So you need 4.25 * 11 kg/mole = 46 kg natural boron to completely prevent criticality in the 100 tons of fuel.

That is not a lot of boron. Reports have been that TEPCO has been putting tons and tons of boron in the water they are using to cool the fuel. If even a fraction of that boron is staying in the reactor, it will prevent criticality.

The report on â??neutron beamsâ? does not seem credible to me.

I share your concerns, and your questioning of official statements that such discharges represent â??no immediate threatâ?. The hazards are actually fairly well documented, if someone is inclined to attend to the historical record (nuclear advocates seem not to be so inclined).

On the one the one hand, we might say that what we have to go on is rough analogies of what may happen as a result of soil and water contamination. On the other hand, we might say instead that we actually have years of experience from around the world what happens when radioactive materials are introduced to the environment. They donâ??t disperse and dilute the way nuclear advocates would want us to believe; the materials settle into the soil and silt and sand, they accumulate not far from the discharge point. And then they just don’t go away. They sit for decades (really, they’re going to sit for centuries), and then they get re-introduced to nearby communities by natural forces, or human activity:

(from http://www.fraw.org.uk/mei/archive/harwell-scram.pdf)

In our first report on safety at Harwell(1) we stated that pollution of the local groundwater from material dumped on the site was a strong possibility, because of the structure of the local geology. In 1990, solvents were discovered in the drinking water of people living around the Harwell area. The source of the water was a borehole three miles from the Harwell site. Later studies showed an underground plume of contamination extending out from the Harwell site towards this borehole.

During the early 1980’s the British Geological Survey conducted extensive surveys of the Harwell area to determine whether or not the local strata were suitable to house a low-level waste disposal site. Their conclusion was that the local geology was very complex, very unpredictable, very porous, and very unsuitable for housing a waste repository. This, to any intelligent scientist, should have set alarm bells ringingâ?¦

To solve the problem it is proposed that a special plants will be built above the waste sites. They will suck up the polluted groundwater, separate the solvents by blowing hot air through the water, and then filtering the air given off to remove the solvents. The groundwater pumped out will be run into the local sewer. Though a practical idea, the Liaison Committee Report does not mention two significant facts. Firstly, low-level radioactive waste is buried alongside the dump sites, and this process will mobilise as much radioactive material as it will chemical contaminants. Secondly, more than 3000 gallons of water per day will be abstracted from beneath the Harwell site. The local water table is already low through abstraction for drinking water. Extra abstraction could have significant effects on the local environment and agriculture.

Downstream AWE Aldermaston has its pipeline, and AWE Burghfield also discharges effluent into the Thames via the River Kennet. What are the cumulative effects of these three discharge points?. It has been noted that an enhanced level of beta activity exist in the silt near the Harwell outfall into the Thames, and that these levels follow a pattern with the levels of caesium and plutonium isotopes within the silt.”

(from: http://www.cdphe.state.co.us/rf/contamin.htm)

Contaminants were released into the air and water during routine manufacturing at the Rocky Flats Plant located 16 miles northwest of downtown Denver, as well as during unplanned incidents. The Historical Public Exposures Studies on Rocky Flats were conducted to identify potential health risks to residents in nearby communities who may have been exposed to chemical and radioactive releases from Rocky Flats during its years of operation (1952 to 1989). After extensive study, researchers determined that nearby communities received the greatest exposure to contaminants through the air, rather than from drinking water.

When the holding ponds on Walnut Creek were drained and reconstructed in 1972-73, some of the pond water and sediments flowed downstream to Great Western Reservoir. Levels of radioactivity in water from Walnut Creek at Indiana Street (the plant’s eastern boundary) increased almost eighty-fold during the peak rebuilding phase. By June 1973, the radioactivity levels had returned to pre-pond reconstruction levels.

In the past, the highest levels of plutonium were detected in water that went into the south branch of Walnut Creek. An estimated one gram of plutonium may have been released to South Walnut Creek from the plant’s start-up in 1952 through 1969. Much of the plutonium in liquid wastes settled to the bottom of the holding ponds and eventually in the sediments at the bottom of Great Western Reservoir.

The greatest amounts of tritium were released to surface water in April 1973, when wastewater containing tritium flowed into Walnut Creek leading to Great Western Reservoir. The highest tritium concentrations measured in the reservoir during this time were from two to 20 times higher than normal.

The discharge of plutonium into Walnut Creek and Woman Creek over many years has resulted in the accumulation of contamination in the sediments at the bottoms of Great Western Reservoir and Standley Lake. Core samples taken of the sediments show low but measurable concentrations of contamination from 5-10 inches deep in the sediments.”

you get this link to a paper about the evidence for possible occurrences of fission (recriticality) since TEPCO attempted to shut down the reactors:

(http://lewis.armscontrolwonk.com/files/2011/03/Cause_of_the_high_Cl38_Radioactivity.pdf)

The key passage in the introduction (from my perspective):

“Most of the nuclear physicists and engineers with whom I have spoken since the incident cannot – will not – believe that it is possible that some of the fuel that is melting could somehow produce little pockets that could go critical.”

If the belief is strong enough, evidence need not be considered. They *will not* believe it. I take it a step further, and say they will not imagine it; criticality should not happen in their world, and so it won’t, hasn’t and bears no further investigation.

And so concerns like this:

“Given these uncertainties it is nonetheless important for TEPCO to be aware of the possibility of transient criticalities when work is being done; otherwise workers would be in considerably greater danger than they already are when trying to working to contain the situation. A transient criticality could explain the observed 13 â??neutron beamsâ? reported by Kyodo news agency (see above). This analysis is not a definitive proof but it does mean that we cannot rule localized criticality out and the workers should take the necessary precautions.”

need not be considered.

http://www3.nhk.or.jp/daily/english/05_25.html

Yesterday it was told that Japan asked Russia to help to deal with radioactive waste. Yes, they have a loong experience in “dealing with” radioactive waste..

http://english.kyodonews.jp/news/2011/04/83116.html

And they are “considering putting up underwater silt barriers at 3 locations, including one near a water intake for the No.2 reactor.”

http://www3.nhk.or.jp/daily/english/05_18.html

Unless South Korea provides a tanker to put the water in now there isn’t much choice. So long as that water is on site they can’t get at the critical systems and the longer they go without critical systems the worse it gets.

http://search.japantimes.co.jp/cgi-bin/nn20110405x6.html

Shanghai is also concerned, I should think.

–bks

The ban was instituted after a few decades of unregulated dumping had resulted in widespread contamination. What the above paper makes clear, we frankly don’t know how much material has already entered the environment over the past fifty years.

We do have some examples of how the materials move through the environemnt. It’s hard to make direct comparisons, but the processes seem to be fairly consistent– concentrations of materials form near the release site, and move slowly though the soil and water. Natural weather conditions (and human activity) cause the material to disperse in locally greater quantities, something than happens periodically as long as the radioactive material remains.

An example from the Chelybinsk nuclear complex in the former Soviet Union illustrates the process:

(from The Bulletin of The Atomic Scientists, May 1991. http://books.google.com/books?id=tAwAAAAAMBAJ&pg=PA28&lpg=PA28&dq=dispersal+of+radioactive+materials++accidents+soil+water&source=bl&ots=oQp9ABViUX&sig=WlmLD3BAXqqioTOLROTemXh3LOU&hl=en&ei=7RuaTbzCA6rk0gHyn_CIDA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBYQ6AEwADge#v=onepage&q&f=false)

“Resevoirs were created to keep water from flowing out of the most contaminated areas, and plant wastes were discharged into Karachay Lake, which has no outlet, instead of into the river.

The lake, actually a bog, eventually accumulated 120 curies of the long-lived radionuclides cesium 137 and strntium 90. In comparison, the Cernobyl accident released one million curies of cesium 137 and 220,000 curies of strontium 90.

In 1967 [about 15 years after dumping began], wind dispersed radiactivity from the lake, contaminating about 1,800 square kilomenters. Today, radioactivity has migrated about about two to three kilometers from the lake. A person standing on the shore near the area where the wastes are discharged from the plant would receive about 600 roentgens of ration, a lethal dose, in an hour.”

And it is important not to get the feeling of being ‘out of the woods’ in the next few months:

(from: http://www.riverkeeper.org/campaigns/stop-polluters/indian-point/radioactive-waste/

“Each reactor routinely emits relatively low-dose amounts of airborne and liquid radioactivity. This radioactivity represents over 100 different isotopes only produced in reactors and atomic bombs, including Strontium-89, Strontium-90, Cesium-137, and Iodine-131. Humans ingest them either by inhalation, or through the food chain (after airborne radioactivity returns these chemicals to earth).

Each of these chemicals has a special biochemical action; iodine seeks out the thyroid gland, strontium clumps to the bone and teeth (like calcium), and cesium is distributed throughout the soft tissues. All are carcinogenic. Each decays at varying rates; for example, iodine-131 has a half-life of eight days, and remains in the body only a few weeks. Strontium-90 has a half-life of 28.7 years, and thus remains in bone and teeth for many years.

These chemicals are different from â??backgroundâ? radiation found in nature in cosmic rays and the earthâ??s surface. Background radiation, while still harmful, contains no chemicals that specifically attack the thyroid gland, bones, or other organs.

â?¦radioactive by-products continue giving off dangerous radioactive particles and rays for enormously long periods â?? described in terms of â??half lives.â? A radioactive material gives off hazardous radiation for at least ten half-lives. One of the radioactive isotopes of iodine (iodine-129) has a half-life of 16 million years; technetium-99 has a half-life of 211,000 years; and plutonium-239 has a half-life of 24,000 years. Xenon-135, a noble gas, decays into cesium-135, an isotope with a 2.3 million year half-life.”