Saturday, April 6, 2013

#Fukushima I Nuke Plant: At Least 120 Tonnes of Contaminated Water with 710 Billion Bq of Beta Nuclides Leaked from One of In-The-Ground Water Storage Locations


(4/9/2013 The latest on the leak in the new post)

===============================

That's according to TEPCO as of April 6, 2013.

The latest is that there may be additional 47 tonnes of the water leaked (Kyodo News 4/6/2013), and that may be from the in-the-ground storage No.3 (TEPCO, latest email to the press (No.12) on 4/7/2013).

And there is a possibility that instead of 710 billion becquerels of all beta in the water there may be 35 trillion becquerels of all beta.

But first thing first, here's my best effort of summarizing the leak incident.

Yesterday, I watched part of the press conference, I read articles, I read tweets, togetters, and I still didn't clearly get what exactly happened and how - why the water was leaking, how much was leaking, when they found out about it, what was their plan, why the water was stored there in the first place.

At least I sort of figured out the last question. The in-the-ground storage, where the leakage occurred, was not supposed to be used for storing the waste water after the Reverse Osmosis (desalination) treatment with high salt content and high beta nuclides. But the multi-nuclide removal system ALPS couldn't start as planned (September last year; TEPCO is now doing the hot trial run), the water treated by SARRY or Kurion's system (cesium removal) had to be stored somewhere to wait for the treatment by ALPS. So, this water is stored in the tanks made for the post-RO waste water. So, for the post-RO waste water, they started to use in-the-ground storage (there are 7 of them) in early February this year, which was originally meant for post-ALPS treatment water.

For the leak of contaminated water, this is what I have gathered from Jiji, Asahi, NHK, and TEPCO:

  • TEPCO dug up 7 locations in the Fukushima I Nuke Plant compound to create in-the-ground water storage, and has started to use them on February 1, 2013. Total capacity of these 7 storage locations is 58,000 cubic meters (tonnes).

  • Construction was carried out by Maeda Construction. They dug up the ground, installed layers of liners, poured concrete to protect and secure the liners, and put in the plastic water storage devices (see the photos below).

  • The storage location 2 holds 13,000 tonnes of the waste water, with max capacity of 14,000 tonnes. This is where they noticed the leak.

  • They measured beta nuclides (35 Bq/cm3) during the routine sampling test of water on April 3 in the drain hole on the northeast corner, and on April 5, 5,838 Bq/cm3 of all beta from the leak detection hole on the northeast corner between the bentonite sheet and unwoven fabric sheet/HDPE sheet. That's when TEPCO determined that the water was leaking into the ground.

  • The storage location 2 is 60 x 52 x 6 meters. TEPCO had confirmed the strength of the protective sheets, but the company did not do a leak test prior to actual use.

  • TEPCO estimated the amount of leak using the data from the water gauge in the storage, and came up with the number of about 120 tonnes, or slightly under 1 percent of the waste water stored. Calculating from the all beta from the detection hole (5,838 Bq/cm3), TEPCO says 710 billion becquerels of radioactive materials may have leaked.


There is also confusing information as to how full these in-the-ground storage locations already are.

BUT WAIT, THAT MAY BE MUCH, MUCH MORE BECQUERELS.

Why? Because the number TEPCO used to calculate the amount of radioactive materials in the leaked water was from the water taken from the leak detection hole in the bottom protection layer, and NOT the waste water in the storage.

So, how many becquerels of all beta does the waste water in the storage have?

  • Asahi Shinbun article which I consulted did say "290,000 Bq/cm3 strontium" in the water in the storage, and that's the number reported by TEPCO on March 6, 2013 as the amount of all beta in the waste water after the Reverse Osmosis treatment. Again, that is the waste water being stored in the holes in the ground with several layers of sheets...

  • Using that number, 290,000 Bq/cm3, instead of 5,838 Bq/cm3, there could be nearly 35 trillion becquerels of all beta in 120 tonnes of the leaked waste water.

  • In the press conference on April 6, TEPCO didn't disclose the radioactivity of the stored waste water, and none of the reporters at the press conference seems to have asked about it.


Here's the link to a togetter in Japanese discussing the above points.

From TEPCO's handout for the press, here's what a in-the-ground water storage facility looks like:





The quality of information coming out of TEPCO's press conference has markedly gone downhill in the past few months.

In the first few weeks of the nuclear accident in 2011 when one of TEPCO's managers who gave press conference was Vice President Muto, very few reporters understood what Mr. Muto was saying. Not because Mr. Muto, who is a nuclear engineer, was obfuscating but because reporters didn't know much about nuclear reactors/plants at all. They didn't know what to ask, they didn't comprehend the answers they got. Mr. Muto himself didn't seem to understand that the (mostly) young reporters didn't have a clue of what he was talking about.

Then came Mr. Matsumoto, TEPCO's PR spokesman, sometime in late March-early April time frame. The reporters were getting up to speed, and Mr. Matsumoto, after initial bureaucratic awkwardness, turned out to be OK, giving out technical information in more or less straight-forward manner. I was impressed when he explained with a straight face, no pretense, in the press conference how his company was trying to stop the leak of highly contaminated water (probably from Reactor 2 turbine building) in early April of 2011 with baby diaper polymers and shredded newspaper, using onsen bath salts as tracer.

Then came Mr. Ono, new spokesman, starting this year. Suddenly, TEPCO's press conference has become muddled again. Mr. Ono, whose manner of speech is not clear to begin with, has a convoluted and confusing way of explaining things to the reporters who are by now quite knowledgeable about things nuclear and particularly about Fukushima I Nuke Plant. I've seen them often lose patience with Mr. Ono, who often becomes defensive. He does not seem to know well enough of the subject matter (nuclear, and this plant in particular) to be able to speak clearly. The reporters, in turn, reacting to this muddled-through way of communication, have reverted back to the initial state of not knowing what to ask.

People say "It's the company, TEPCO". I'm inclined to say it's this particular spokesman who is wiping out what credibility TEPCO had accumulated in the past 2 years by trying to be straight-forward in disclosing information.

18 comments:

Anonymous said...

Sadly, this was predictable, and sadly, the wrong conclusions will be taken.
The priority is treating the excess water and getting rid of it (yes, that means running it out into the ocean, where the ulra-dilute and little radiotoxic tritium is essentially going to be harmless).
This will allow people to concentrate on the clearing the fuel pools and then working on the reactors themselves.
ALPS was basically ready months ago, but the bureaucrats thought out some crazy new tests, so it is only starting a hot test run now.

And the strontium-contaminated water is accumulating and now leaking…

But wait: someone flicked a wrong switch, and ALPS hot run stopped.
So now, they will ponder some more weeks about how to change the system (and write a new rule book, and submit this to NRA, which will comment, which will prompt new changes, new rules, etc.).

And meanwhile, the contaminated water is leaking…

Oh, no time to work on ALPS, we first have to write a report about the tank leak, and work on 50x redundancy for SFP cooling, because the pool would risk overheating after a few weeks(!) without it.

And meanwhile, the contaminated water is leaking…

Somehow, this reminds me of the story about the batteries missing during the accident, because regulations didn't allow their transport!
Neither TEPCO nor the regulators seem to have learned anything useful from the accident, though…

Anonymous said...

laprimavera, I think you missed a "など" after strontium.

「…セシウム吸着装置で処理した後のストロンチウムなどが含まれた高濃度の汚染水。1立方センチメートルあたり約29万ベクレル。」って

arevamirpal::laprimavera said...

Nah. など is mostly for the reporters and TEPCO to cover their behinds.

ALPS used the touch screen that was too sensitive, and the worker had to use a very blunt touch-pen. They decided to stick with using the mouse (computer, not the living one).

Anonymous said...

In this case it just indicates that the only isotopes that have been removed are Cs-134 and Cs-137, so any other beta would be there (among them strontium.)

Atomfritz said...

Wow, thank you LaPrimavera for the effort finding out this information about these "tanks"!

So Tepco seems unsure whether "tank" #3 is also leaking or it's just radioactivity from "tank" #2's leak.

By the way, Tepco stating that no new unexpected water level decrease is being observed at "tank" #2 should be treated with caution, as we know which difficulties Tepco often has in measuring/estimating water flows.

In fact, this Tepco statement can thus serve as a reassurance only in the sense that at the moment a flood caused by a collapsing "tank" is possibly not yet imminent.

Vyse Legendaire said...

Good write up, I'd be kind of clueless about this without this blog's collating skills. I have to concur with above poster about "where the **** is the dilution system"?

Anonymous said...

Primavera-san,
if the water had only cesium removed the strontiumなど means strontium and all the rest of the arsenal, right?

Beppe

arevamirpal::laprimavera said...

TEPCO says "all beta", as I wrote in the post. Strontium is the most abundant beta.

Atomfritz said...

Beppe, according to Tepco the "tank" #2 water seems to be SARRY output.

LaPrimavera posted a link to a table containing the decontamination statistics of SARRY some time ago, iirc.

Thus, the water probably contains the whole cocktail of beta and the lesser (i.e. non-cesium) gamma radiators, and the alpha radiators which were washed out from the molten cores.

At least workers can approach and study the leak and the contaminated soil without being insta-roasted by cesium gamma :) Isn't this good news? :)

Anonymous said...

I had a liking for Matsumoto and I felt sad when he left the press conferences.

arevamirpal::laprimavera said...

Atomfritz, as far as I know the radioactive slurry from SARRY is stored in the metal vessels. What's in these in-the-ground storage areas is the waste water after RO, which comes after SARRY treatment.

Yosaku said...

arevamirpal::laprimavera,

You can find the activity of the stored water here on page 15: http://www.tepco.co.jp/nu/fukushima-np/handouts/2013/images/handouts_130407_02-j.pdf

This shows total beta of 290,000 Bq/cm3.

As for how much of this water actually leaked, that will be hard to put a number on, especially until we see it hitting the main monitoring wells on site. Bentonite in a geosynthetic clay liner such as this is an extremely effective barrier and the last line of defense because it can soak up an incredible amount of water, often increasing 10 to 15 times in volume (and is often self-healing because of this). Depending on the thickness and type of sheet used, I wouldn't be surprised if it soaked up much of the leak.

Anonymous said...

Right, so など means the whole assortment but Cesium.

Also, the credibility of Tepco should not be measured on how likable their propaganda spokesman is. Recently Tepco has been summoned at the diet to explain why they "allegedly" obstructed an attempt of the nuclear regulatory commission to asses the damages caused to unit 1 by the quake (Tepco would prefer most of the damage to have been caused by the tsunami). On that occasion Tepco admitted to have lied even on the weight of portable safety equipment in order to discourage the commission.

As reported by this blog, Tepco has also failed to disclose that they knew that half of the water from the firetrucks did not reach the reactor.

Tepco still has a long, long way to go before it becomes credible.

Beppe

arevamirpal::laprimavera said...

Beppe, I'm not talking about likeability. I didn't like or dislike Matsumoto. I was impressed with his straight face day after day as I watched the presser, reporting horrendous, amusing, or technical news. He was more or less open to the reporters, said he didn't know when he didn't know.

The current one always tries to spin it as if he knew something (he doesn't, that's very apparent if you watch). No trust.

Atomfritz said...

LaPrimavera,
is there any information how thick the PE sheets are?
Even more information, type/manufacturer etc?
How were the sheets glued together to form the "tank"?

Yosaku,
did you know the bentonite layer there is only 1/4 inch thick, according to Asahi?
To provide effective pit tightness, there is needed 10 inches clay at the minimum, I always believed.
Even more if the tightness is a critical issue, like at industrial wastes.
Every common sewage pit is tighter than this "radwaste storage tank"...

arevamirpal::laprimavera said...

I'm trying to figure out what's going on with these sheets right now.

TEPCO sure has a PR disaster in the person of Ono.

Yosaku said...

Hey Atomfritz, Good to hear from you. Thanks for confirming the thickness of the GCL, which appears to be average. GCLs are often used to replace compacted clay liners in certain applications. The key is not the thickness but rather the hydraulic conductivity, and here GCLs generally outperform CCLs. In addition, GCLs are less prone to cracking than CCLs and are better at self-healing. On the flipside, GCLs are more susceptible to punctures given their thinness. I've used both GCLs and CCLs under different applications. Back in the day, as the junior engineer on the team, my office became the repository for all of the samples of GCLs, HDPE liners, non-wovens, etc. the firm received from different manufacturers. In fact, I still have an example of an HDPE weld sitting somewhere around my house.

Anyway, my biggest question is why they poured the concrete directly on to the HDPE liner (or at least it appears this way from the photos). This seems like a bad idea to me. I would have thought they would put in a 3 or 6-inch lift of soil or other material between the two to protect the liner. Landfill and storage ponds like this generally leak the most during seasonal changes as the land shifts to reflect changing temperatures and groundwater levels and having the HDPE directly against the concrete could lead to significant damage as the concrete adjusts differently than the surrounding soil.

Yosaku said...

arevamirpal::laprimavera,

I just saw the discussion about salinity affecting adsorption in your most recent post on this topic. Excellent point.

Post a Comment