Update #64: Sept 24 & 25
From 1% to 4% to 100% Hydrogen
The lead story in our last report concerned the hydrogen concentration in a pipe at Unit 1.
Prior to cutting the pipe to install a device to control radioactive gases, TEPCO measured the concentration of hydrogen in the pipe and reported it at over 1% (10,000 parts per million). Now it appears the company has brought in proper testing equipment and found 100% flammable gas in the pipe, likely mostly hydrogen. Now we await the report from TEPCO on the reading from the instrument which measures only hydrogen, not all flammable gases. SKF reports as follows:
TEPCO: It May Be 100% Hydrogen Gas Inside the Pipe Connecting to Reactor I Containment Vessel
First it was reported that "over 10,000 ppm" or over 1% of hydrogen gas was detected at 2 locations in the pipe that connects to the Containment Vessel of Reactor 1 at Fukushima I Nuclear Power Plant. Then it was allegedly "over 40,000 ppm" or 4%.
According to Jiji Tsushin, TEPCO thinks the hydrogen gas concentration in the pipe may be 100%. 1,000,000 ppm.
Still, TEPCO says possibility of explosion is not necessarily high because there is no source nearby that could cause sparks. (Never mind that they were going to use blow torches to cut the pipes…)
Jiji Tsushin (12:28PM JST 6/24/2011): [Japanese characters removed]
Concerning the detection of hydrogen gas in more than 1% concentration inside the pipe that connects to the Containment Vessel of Reactor 1 at Fukushia I Nuclear Power Plant, TEPCO announced on September 24 that it is highly probable that almost all the gas inside the pipe is hydrogen gas. TEPCO's Matsumoto said in the press conference, "Since there is no source for sparks, it cannot be said that there is a high risk of explosion immediately".
According to TEPCO, they measured the gas at the pipe exit several times in the afternoon of September 23. Each time, the result showed "flammable gas including hydrogen gas, over 100%". [One assumes they mean the instrument went off-scale at 100%.] The company plans to use the instrument that only measures hydrogen, in order to accurately measure the concentration of hydrogen.
It's so TEPCO. First they used the device that could only measure up to 10,000 ppm, and that maxed out. Then they apparently used the device that could only measure up to 40,000 ppm, and that maxed out. So they brought in a bit more powerful instrument, but it measures all flammable gases including hydrogen.
I suppose they were hoping that one of these devices would suffice. But now, even they have admitted that the air inside the pipe may be 100% hydrogen.
Source: http://ex-skf.blogspot.com/2011/09/tepco-it-may-be-100-hydrogen-gas-inside.html
SARRY Decontamination System Down
The next story this weekend concerns the shut-down of the new SARRY decontamination system.
TEPCO had such high hopes for this system they announced that as of October 1st they would be shutting down the other 2 decontamination systems (Areva & Kurion) which experienced 32 shutdowns in first 2 months of their operation. Here is the post from Physics Forum which quotes the TEPCO press release on this shutdown.
________________________________________
SARRY line A was used for the first time on 23 September:
9 / 23 16:53 We activated second cesium adsorption facility (System A and System B). At 17:03, the flow rate achieved steady state (approx. 40 m³)
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110923_03-e.pdf
Then on 24 September:
*At approx. 8:30 pm on September 24, the second Cesium adsorption facility
of water treatment facility has automatically shut down. Investigations
are now underway. Water treatment by Cesium adsorption facility is
continuing. As there are sufficient treated water stored in the tank,
there is no impact on the water injection into the reactors.
http://www.tepco.co.jp/en/press/corp-com/release/11092502-e.html
So it seems that both lines A and B of SARRY are down. The Kurion system is running. The status of the Areva system is unclear.
Source Physics Forum: http://www.physicsforums.com/showpost.php?p=3521255&postcount=11353
Reactor Data: What does "Cold Shutdown" Mean at Fukushima?
An interesting discussion unfolded on Physics Forum following the release of a TEPCO video on the status of the measuring instruments in the reactors. This is a short video with English voice-over translation and well worth watching. The link is in the first comment posted below.
As recently mentioned in these reports there have been many questions regarding the reliability of the instrument data on the state of temperature, pressure, radioactivity and water levels in the reactor units. As you will see in the first post below, those concerns are well justified and led to a fuller discussion of "cold shut down" at Fukushima.
(Not all comments in the string are reprinted below. I have put my interjections in brackets this, [N: …])
________________________________________
Comment #11320
New video released by TEPCO on the status of the measuring instruments.
http://www.youtube.com/AtomicPowerReview
Fantastic link thank you!
Regarding the thermocouples on which 'cold shutdown' claims will be based, some are deemed to be 'overscale', some 'underscale', and some destroyed.
Of the remaining:
"we think that the data collected at the moment is reliable to some extent. We are not sure if the accuracy of the detectors of each thermometer is within the limits of the calibration or not, but according to the overall trend, we think that such temperature estimates will be probable. Also, recently, we can change the water injection rate to the reactor, and it appears as the temperature shift, therefore we think that the soundness of the thermometer is secured"
[N: So what TEPCO is saying is that the thermometer measures changes in temperature; but they cannot guarantee the actual temperature reading is accurate. That of course would be fine if they were not basing their definition of "cold shutdown" on the temperature at the bottom of the RPV being below 100 degrees C. ]
Comment #11333
Actually in US GE BWRs [boiling water reactors], Standard Technical Specifications define the mode called "Cold Shutdown" as the Reactor Temperature less than 200 degrees Fahrenheit, the mode switch in "Shutdown" and all RPV head bolts fully tensioned.
In the current condition of the Fukushima plants I would not say the plants have achieved "Cold Shutdown in a legal sense because:
1. Mode switch may be in shutdown, but Reactor Core subcritical reactivity cannot be guaranteed.
2. The physical condition and accuracy of thermocouples measuring reactor temperatures is unknown.
3. RPV damage may have occurred making the condition of the RPV head bolts (assuring the coolant system integrity) meaningless.
Since the Unit 4 RPV Head is removed and the core is located in the spent fuel pool, that unit is in Refuelling Mode.
Once core degradation started and the geometric integrity of the core was altered the normal meaning of shutdown went out the window. I think that Japan and TEPCO accident need to be careful using terms that can be misunderstood.
Comment #11338
… I think perhaps the media are bit cautious of the cold shutdown stuff because they are tending to write it inside speech marks, slightly implying that it isn't exactly cold-shutdown in the very routine sense of the term. And plenty of media still casts a less-rosy picture of the situation as they talk about things like the reactors 'still billowing out radiation'. But at the same time they do not go completely nuts about the way the Japanese are portraying the situation.
Will just have to wait and see what happens if/when the Japanese decide to use this 'cold shutdown' stuff to relax evacuations. Spinning seems understandable, but if they try to use that spin to expose people to unforgivable risk, then we need to shout more about this stuff.
[N: This final comment really speaks to the essence of the problem of using the term "cold shutdown" in relation to the Fukushima reactors, namely how it will affect public safety.]
TEPCO Video Releases Show Steam Venting at Units 2 & 3
The video for Unit 2 is shot through the blowout panel on the side of the reactor building. You can only see the very top cap of the reactor in the video, but the large amount steam is evident.
The video of Unit 3 shows the devastation at Unit 3 which experienced the largest explosion. You see puffs of steam near the "rust stain" at the bottom of the exposed portion of the reactor.
This short clip from a Japanese news broadcast is the best way to see the steam venting from the reactors.
Japanese newscast with good shots of steam from the videos.
Source: http://www.youtube.com/watch?v=wYxYWS75iVs&NR=1
The full Unit 3 video is here
http://www.youtube.com/AtomicPowerReview#p/a/u/0/YQWT538Hn9Q
and the full Unit 2 video here.
http://www.youtube.com/AtomicPowerReview#p/a/u/1/VoS7nbgboag
Contamination
Most of the press is carrying the story of radioactive contamination of rice above government limits in Fukushima prefecture. Here is the Mainichi news story:
Fukushima finds cesium in Nihonmatsu rice, to hold more tests before shipment decision
The Fukushima Prefectural Government said on Sept. 23 that it had detected 500 becquerels of radioactive cesium per kilogram – the government-set allowable limit – in a sample of "Hitomebore" rice collected in Nihonmatsu's Obama district. It will greatly increase the number of testing locations there for a second test to decide whether to allow shipments of rice from the city. […]
According to the prefectural government, 500 becquerels of radioactive cesium were detected in a rice sample collected on Sept. 12, and soil in its paddy field contained 3,000 becquerels of cesium per kilogram. Rice crops from 11 other locations in the Obama district had from undetectable amounts up to 212 becquerels of cesium.
Note that the sampling is not being done on ALL rice crops. It is selective sampling only.
[…] Preliminary tests such as the one that found the problem rice in Nihonmatsu are being conducted about one week before harvesting in 370 zones covering the whole prefecture. Those municipalities where rice with 200 becquerels or more of cesium are found are designated as "priority test areas." Such areas get two testing locations per 15 hectares of land for a later second test that determines whether shipments from the zone will be allowed.
Full story at source: http://mdn.mainichi.jp/mdnnews/news/20110924p2a00m0na017000c.html
Meanwhile, this is how the Yokohama City workers (or the contract workers) "cleaned" the highly contaminated (42,000 becquerels/kg cesium) dirt from the side of the road. No protection, no masks, no rubber boots.
Yokohama City Assembly recently voted down the citizens' petition asking the city not to accept radiation-contaminated disaster debris from Tohoku by the majority vote by the DPJ and LDP and Komei Party.
The city temporarily halted the dumping of radioactive sludge ashes into the ocean as the citizens' protests were fast and furious once they knew about the scheme, but the mayor in the press conference took pains to emphasize that only thing that had gone amiss was that the city officials under her clearly didn't "explain" well enough to the Yokohama residents living in the area around the final dumping site in Minami Honmoku Pier in advance. "We should have explained better to soothe the fear and anxiety of the residents", she said.
The mayor, who fed 80,000 elementary school children in the city with radioactive beef, then went to an APEC's women's meeting in San Francisco and appealed Yokohama. (As what?) […]
And finally SKF carries this contamination story.
105,600 Bq/Kg of Radioactive Cesium from Apartment Bldg Rooftop in Yokohama City
The apartment building is located in the same Kohoku-ku in Yokohama City where 63,000 becquerels/kg of radioactive cesium was found also from the rooftop of another apartment building, and 42,000 becquerels/kg was found from the dirt around the side drain on the road.
It looks like this person had the dirt on the rooftop tested on his own, and posted the test result sheet on his blog.
Cesium-134: 49,900 becquerels/kg
Cesium-137: 55,700 becquerels/kg
Total radioactive cesium: 105,600 becquerels/kg
[Test sheet at link]
Meanwhile, Yokohama City workers (or the contract workers) "cleaned" the highly contaminated (42,000 becquerels/kg cesium) dirt from the side of the road. No protection, no masks, no rubber boots.
Yokohama City Assembly recently voted down the citizens' petition asking the city not to accept radiation-contaminated disaster debris from Tohoku by the majority vote by the DPJ and LDP and Komei Party.
The city temporarily halted the dumping of radioactive sludge ashes into the ocean as the citizens' protests were fast and furious once they knew about the scheme, but the mayor in the press conference took pains to emphasize that only thing that had gone amiss was that the city officials under her clearly didn't "explain" well enough to the Yokohama residents living in the area around the final dumping site in Minami Honmoku Pier in advance. "We should have explained better to soothe the fear and anxiety of the residents", she said.
The mayor, who fed 80,000 elementary school children in the city with radioactive beef, then went to an APEC's women's meeting in San Francisco and appealed Yokohama. (As what?) […]
Source: http://ex-skf.blogspot.com/2011/09/105600-bqkg-of-radioactive-cesium-from.html