http://www.ambersharick.com/Day%2027.html
Update from Dr. Saji- former Secretariat of Japan’s Nuclear Safety Commission
Last Update: 9 April 2011
Dear Colleagues:
27th day!
I. Stop that leak?
After the successful operation performed yesterday, the sea water sampling at the sea water discharge inlet reduced down to 5700 Bq/cm3, a factor of 50 decrease from the value of samples taken on April 2. Likewise, Cs-137 concentration was 3200 Bq/cm3. These values indicate that the leakage from the pit to the sea water was stopped.
It was reported yesterday that the water level in the trench of 1F2 has increased by 5 cm, however, it went back to the original level on the morning of April 7. This may indicate that the water leaking from the basement of the turbine hall of 1F2 found its way to the trench. TEPCO is keeping a close eye on the water level, as well as possible leak to other locations.
II. Nitrogen gas injection into the containment vessels
TEPCO announced last night that they started to inject nitrogen gas into the 1F1 containment vessel, starting at 10:30 PM on April 6. According to their press release, this operation is to reduce a risk of air seepage into the containment vessel with its temperature expected to go down with further cooling. It is a kind of a vacuum breaking operation, when there is no damage in the containment vessel. However, there is some indication of potential damage in 1F2. Currently, there is a possibility that the atmosphere inside of the containment vessel contains high concentration of hydrogen gas. There is very little risk of hydrogen explosion at this stage, since it is filled with steam supplied from the reactor vessel being cooled by water injection. Following trial N2 gas filling into 1F1, whose containment vessel appears to be only with a minor damage, both 1F2 and 1F3 containment vessels will also be filled with nitrogen gas.
The injection is being done from a N2 gas generator (from a liquid nitrogen tank car?) temporary connected to the inert gas-charge line. The isolation valve of this charge line was opened to fill the drywell of the containment vessel with nitrogen gas.
They intend to charge as much as 6000m3 in the coming 6 days. Since there is no appreciable change in the area monitoring indication, it appears that no appreciable leak is taking place during the current nitrogen charging.
I think it is prudent to inject nitrogen, since the water injection into the reactor vessel also introduces dissolved oxygen, in addition to the oxygen produced by decomposition of hydrogen peroxide generated through water radiolysis. However, depending on the amount of nitrogen injected, the hydrogen may also leak from the damaged portion of the containment vessel. Therefore a very careful operation is necessary.
III.Total capacity necessary for storage of the contaminated water
The extended feed and bleed operation, as well as sea water injection into the reactor vessels and into the spent fuel pits, resulted in unprecedented quantity of highly contaminated water during the recovery operation being performed. The contamination level is further aggregated by suspected leakages of the reactor water from the containment vessels. A news source from NISA (Nuclear and Industrial Safety Agency) revealed the following estimation.
Source of the contaminated water:
Turbine halls:
1F1 20,000 tons (including 3,100 tons of likely sea water in the trench left by the tsunami)
1F2 20,000 tons (including 6,000 tons of highly contaminated water)
1F3 20,000 tons (including 4,200 tons of likely sea water in the trench left by the tsunami)
Condensers:
1F1 1600 tons
1F2 3000 tons
1F3 3000 tons
Capacity for storage:
Condensate storage tanks:
1F1: 1,900 tons
1F2: 2,500 tons
1F3: 2,500 tons
1F4: 2,500 tons
Central waste processing facility: 30,000 tons
Suppression pool water storage: 2 X 3,400 tones (currently almost full)
Mega-float facility:10,000 tons (being tugged from Shizuoka to Fukushima)
Planned temporary storage tanks: 20,000 tons
Total capacity: Approximately 70,000 tons (including approximately 20,000 tons already in full)
Shortage in capacity is approximately 10,000 tons.
In view of these statistics, TEPCO has started to construct large temporary storage tanks, as well as ordered approximately 400 smaller sized tanks with capacity of 10-40 tons. The manufacturers of the catalogue-sized tanks are being collected from stocks by the middle of this month.
Even if the contaminated water is filled with these tanks, the waste disposal is already expected to be a headache, with its high activation level, complicated with the seawater injection. Some people are investigating for application of zeolites as well as layered hydrazinium titanate for sorbent for radionuclide absorption.
A research on effects of competition reactions has been initiated. The sorption is prevented by anions in the sea water, such as Ca and Mg.
The most recent activation data of the contaminated water at the basements are not available now, due to some errors found in the earlier press releases from TEPCO. The following data taken at the trench of 1F2 is said to be close to the water inside of the basement of turbine hall.
Unit 2 trench water sampled on March 30.
Species Half Life Concentration (Bq/cm3)
Nb-95 35d ND
Tc-99m 6.04h 1.6E+04
Sr-89 50.5d (estimated value is 2.7E+07. Not measured?)
–
Sr-90 29.12y (estimated value is 1.8E+06. Not measured?)
Te-129m 33.6d ND
Te-132 3.26d ND
I-131 8.04d 6.9E+06
I-132 2.3h ND
Cs-134 2.06y 2.0E+06
Cs-136 13.1d 1.8E+05
Cs-137 30.0y 2.0E+06
Zr-95 64d –
La-140 2d 2.0E+05
Ba-140 12.7d 3.7E+05
The estimated concentration of Sr-89 and 90 are supplemented in the above table, by scaling from the Cs-137 concentration, since no values have been reported from TEPCO. Considering the beta-ray burn incident of the three electricians irradiated in the skin of their feet, it is obvious that these radioactive species should be included in the contaminated water. It is likely the radiation injury was though Sr-89, considering its high concentrations.
This table also indicates a possible strategy of processing the waste water. It should be practical to store the contaminated water for an order of a few years, waiting until the activities from Sr-89 and I-131 reduced lower than the Cs-137 activation. Find an appropriate sorbent material for removal of Sr-89 and Cs-137 under the competition of impurities of sea water such as Ca and Mg.
IV. A memo for lessons learned from the tsunami-induced nuclear disaster (continued)
For memory sake, let me add lessons learned.
(34) Radiation detectors for beta-emitting spices, in particular Sr-89 and Sr-90.
It is very strange that the radiation concentration data by TEPCO continue to ignore presence of Sr-89 and Sr-90 in spite of the beta-burn radiation injuries affected by three workers. The strontium isotopes are particularly important in an event of discharges of contaminated water to the sea, since there is a concern of food chain through fish, concentrated in the fish bone, together with calcium.
end quote.
As suspected. Awaiting US DOE soil sample analysis of radionuclide characteristics gathered from fallout zone 9 April 2011.
Strong possibility the above mentioned radionuclides will be present not only in the pooled water, but in the soil off site.
Information not published in the mass media.
Thanks to Andrew Kishner and partner for finding the above information source
and posting it at their http://www.idealist.ws/ site