(For the latest on April 10, 2013, see my latest post with continuous update.)
(For more information, see the previous post on the leak, including photos of the "pond" construction.)
While the Nuclear Regulatory Authority has said there is no other choice but to continue using the in-the-ground water storage (as they themselves are partly responsible for the current mess because of their insistence on ALPS vessel safety, which has significantly delayed the deployment of the system), a blame game is starting between TEPCO and the construction company who built these storage facilities in the ground.
TEPCO, after having speced out the in-the-ground water storage for Fukushima I Nuclear Power Plant, contracted Maeda Construction, a second-tier general construction firm. TEPCO is blaming Maeda Construction for the faulty construction, and Maeda Construction is blaming TEPCO for sloppy specs.
Or both, is my guess. And some more.
Latest information from Mainichi Shinbun (4/9/2013):
Liners used for the in-the-ground storage construction:
1st and 2nd layers: Polyethylene (HDPE) sheet, 1.5 millimeter thick
3rd and the bottom layer: Bentonite sheet, 6.4 millimeter thick
Leak detection pipes were installed through the 1st and 2nd layers
"Similar specifications have been used for constructing agricultural ponds. There is no problem if the leak detection pipes pierce through the layers, as long as the location is above the water."
Maeda Construction's claim:
"In water storage ponds, if such pipes are used that pierce through the liner sheets, the sheets may get pulled by the weight of the water, creating the gap through which the water could leak. Therefore, you don't spec these pipes to pierce through the sheets. As to the sheets themselves, we have used them for the storage facilities for solid objects, but never water."
TEPCO's spokesman Mr. Ono claimed in the press conference that the bentonite sheet must have absorbed a large chunk of radioactive strontium, and that justified TEPCO's announcing 710 billion becquerels of all beta in the leaked 120 tonnes of waste water.
But wait... This is no ordinary waste water. It is extremely saline.
Another Mainichi article (4/7/2013) quotes Professor Hideo Komine of Ibaraki University (civil engineering and geotechnology), who says:
[There is a possibility that] because of the high salt content in the waste water, bentonite did not expand, and didn't function as waterproof material.
The thicker the bentonite sheet, the more waterproof. The sheet used at Fukushima I Nuke Plant may not be thick enough.
Oops. But wait, there's yet some more. It's not just salt in the water. There are also cation (or positive ion). There are people who thinks the effect of radioactive materials, salt, and cation in the waste water on the bentonite sheet must be studied.
On a comical note, TEPCO has sent out the email notice No.20 to the press (which these days they post on their websites, a slight improvement) saying the company has resumed transportation of waste water from the pond No.2 (the one found with 120-tonne leak) to the pond No.1.
Resumed? Yes, resumed. It was stopped. Why was it stopped? Well, it was stopped when they noticed that some of the water they had transported to the pond No.1 was coming back into the pond No.2.
Why? you ask? TEPCO says it must have been a siphon effect.
OH WAIT... TEPCO just published the email notice No.21, and it says:
We conducted the analysis of water taken this morning from the in-the-ground water storage No.1 drains (2 locations) and from the leak detection pipes (2 locations).
According to the result, chloride concentration of the water taken from the leak detection pipe (northeast) rose to 910ppm from 4ppm yesterday.
Transfer of water from the in-the-ground water storage No.2 to No.1 using the temporary pumps was halted at 12:47PM.
So the pond No.1 is leaking. First it was just No.2, then No.3. If they cannot use No.1 and No.3 (they continue to use No.3 despite the leak, which they claim very minor), 27,000-tonne capacity is removed from the total 58,000 tonnes from 7 ponds.
When I saw him yesterday via the vid, Mr. Ono, TEPCO's spokesman, was rather confident that the water leak may not be that bad, because the layers may have effectively absorbed the water.
And the biggest problem: radiation levels. Even though most of gamma nuclides have been removed, the water contains 290,000 becquerels/cubic centimeter of all betas (mostly strontium). The radiation level on the surface of the waste water may be as high as 2 sievert/hour (beta radiation only), says independent journalist Kino, citing the leak from a tank storing the same waste water that happened on February 3, 2012. (Here's TEPCO's document, in Japanese; see pages 2 and 3.)
Let's check in to their latest presser (2:30PM local time) and hear what he has to say.
(Independent journalist Ryuichi Kino just tweeted that he is hurrying to the press conference, but says he got the email notice at 1:35PM, and sighs, "This is so like two years ago...")
(UPDATE) TEPCO press conference is still going on, nearly two hours after the start. My take is that TEPCO are in big trouble, trying to find any empty storage that can take 400 tonnes/day of the waste water after RO... Mr. Ono is very subdued today. A lot of reporters, and the room is almost full.