Kyodo News (2/18/2012):
福島第１原発２号機で圧力容器底部の温度計が異常な高温を示した問題で、東京電力は１８日、同じ高さにある別の温度計の値を代表的な温度として採用することとし、３０度前後になったと発表した。
Regarding the thermocouple that exhibited abnormal temperatures at the bottom of the Reactor 2 Pressure Vessel at Fukushima I Nuclear Power Plant, TEPCO announced on February 18 that the company had decided to pick another thermocouple at the same height as representing the temperature at the RPV bottom. The official RPV bottom temperature was now about 30 degrees Celsius, the company said.
東電は「同じ底部にあり、健全性が確認されている」と説明している。
TEPCO explained that "the new thermocouple is also located at the bottom of the RPV, and it has been confirmed to be working".
圧力容器底部には、容器を囲むように同じ高さに温度計が三つ設置されている。これまで代表点としてきた温度計の数値が２月初めごろから大幅に上昇したため、東電は故障と判断。配線がほぼ断線状態になったとみている。
There are three thermocouples at the bottom of the RPV at the same height, surrounding the RPV. The temperature at the thermocouple that had been used as official temperature gauge for the RPV bottom [of Reactor 2] started to rise sharply in early February. TEPCO has determined that it is the instrument failure in which the wires have been nearly severed.
The new and improved official thermocouple for the RPV bottom is "69H2", as of 5PM on February 17, 2012 when "69H1" exhibiting -3 degrees Celsius was unceremoniously ditched. (See TEPCO's plant parameters for Reactor 2 RPV temperature as of 2/19/2012 11AM.) The ever-incurious TEPCO also stopped measuring the Reactor 2 RPV temperatures every hour.
The temperature at the CRD Housing is now 212.6 degrees Celsius, after it started the steady rise on February 14 from 112 degrees Celsius. Conveniently, the thermocouple there is also suffering the instrument failure.
On the other hand, the temperature at the "RPV Drain Pipe Upper Part" has plunged from about 50 degrees Celsius in mid January to -0.3 degrees Celsius on February 19, but it is not considered the instrument failure.
Nothing to see here, move on, say TEPCO and the government.
30-Day free trial by following the link.
Tokyo Time
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15 comments:
They are incurious as they know if they open pandora's box further it is over. We remain in a state of wondering where the Waldos went.
#&@%$&#*@$:%#*!!!!!!!
They make me sick. No pun intended
Thermocouples are failing left and right, probably the insulation material has reached its limits. I think soon there won't be working ones left. Then there will be problems with deciding how much water to pump in.
I don't know what a good proxy measurement would be. All I can think of right now is dig through the walls and pop IR cameras into the PCV, at various levels.
What is wrong with this "Picture"?
1. Tepco is one the "GANGS" that runs Japan.
2. What is good for TEPCO is good for Japan.
3. The Japanese people MUST OBEY TEPCO for the
... "GOOD" of the Country.
4. The financial health of TEPCO is more important than
....The physical health of the Japanese People and all
... Their FUTURE children!
5. Only TEPCO knows what is best, all others must BOW
... To TEPCO's Rule.
+
Japan is now a majority TEPCO Stock Owner, where is their TEPCO Board seat and who is asking questions and demanding answers for all those in Tokyo receiving TEPCO's radioactive fallout?
This is UNACCEPTABLE!
Who wants to star in a Japanese radioactive pollution Film!
It's just the messenger of the bad news who gets shot, like in ancient times.
Nothing new.
If Tepco actually would be interested in what happenens in the containments, they'd drill measurement and surveillance holes, as anon 2:39 stated.
The fact they didn't publish any data and did no actual measurements (radiation, temperature, humidity etc) through the existing peephole of Unit #2 indicates that this recent "reactor video" was pure show business.
My personal guess is that they'll "shoot" all thermocouples that read undesirable values, and some time later declare that no more water cooling is necessary.
Basic question: where is all this water going?
It's going to the basement.
Given almost a year of malign neglect, with huge overtemperatures and periodic inundations, it is a miracle these thermocouples are still giving any useful signal.
'Anonymous' is exactly right, the thermocouples will all soon become useless.
At that point, the only way to monitor the reactors will be to check diligently for fission byproducts which would indicate a recriticality has occurred.
Imho, the reactors are in a reasonably stable state, they are spitting out contamination still, but at an irrelevant level compared to the massive emissions early in the accident.
So if nothing else breaks, TEPCO has a clear shot at cleaning up the site gradually, over the next several decades. It is quite possible however that flooding the reactor vessels could lead to recriticality, so TEPCO will be very cautious about any aggressive initiatives.
There has been earlier work highlighting this risk
http://www.osti.gov/bridge/purl.cover.jsp?purl=/16911-VGVXER/webviewable/
identified by Jim Lagerfeld here:
http://www.physicsforums.com/showthread.php?t=480200&page=774
What this really means is that we are stuck, there is no known way to clean up these reactors and we are more likely to do enormous additional harm than good with any aggressive new interventions.
It would be a useful question to ask NISA or TEPCO or JAIF or the Japanese government:
Assuming the current TEPCO cleanup timeline, how much additional contamination is expected to be emitted from the Fukushima 1 site and what impact does this have on the contamination of the surrounding countryside?
@12:40,
Is there a defined figure for "irrelevant level" of contamination available from physicsforums ? While the amount is no doubt smaller than the days during the explosions, there are still continuing emissions to the air and water. It would be useful to hear the experts opinion on what constitutes a harmful amount.
The initial emissions were estimated at around 10**17 bequerels, possibly more.
Current emissions are around 10**9 bequerels/day and declining, so in the next thirty years, about 10,000 days, that will be around 10**13 bequerels, only one ten thousandth of the initial blast.
That is why I use the word 'irrelevant'.
Things in Japan are about as contaminated as they will get. There may be more problems locally if that contamination is concentrated through runoff or human activity, but the reactors have done their worst, barring a recriticality.
Do note that a recriticality would be quite unpredictable, as the only control mechanism is pouring on borated water.
As a side note, the annual emission of radioactive materials from an operating nuclear plant is in the range of 10**11 bequerels, mostly from noble gases and tritium. The Fukushima situation however is different, because these emissions include cesium, which is normally only about 10**6 bequerels worth annually.
The statement that there won't be massive new contamination spewing from Fuku-1 bases on the assumption that from now on there won't happen any more onforeseen unpleasant things.
But there are plenty of possibilities.
For example, a new tsunami now, while this temporary "wall" stands there, would flood the deteriorated reactor buildings, turbine halls etc and distribute a good part of the perhaps 20 kilograms of radioactive cesium contained in the basements water in the puddle that would submerge the buildings for a while, because the water got trapped in the provisional "wall".
When this water dries out, it cannot shield the radiation of the stuff it contains anymore.
The whole contaminated plant area around the reactors might become then inaccessible for carbon-based creatures due to high gamma radiation.
Then the spent fuel pools would dry out eventually.
And, somehow almost no media talks about the spent fuel pools.
This is possibly not without good reason.
In fact, there are some hints that a big part of the radiation emission occurred from the reactor 4 spent fuel pool, and not, as repeated over and over again by Tepco, without revealing any reason or proof, from reactor 2.
Actually, it's really contradictory.
We get told that most of the radiation release would have come from reactor 2.
But, now they work mainly at reactor building #2, because it is the least radioactively contaminated one and #1 and especially #3 are way too radioactive to do anything there.
This somehow doesn't match.
Christian Mueller, a german nuclear safety professional, has published an interesting report on his web site tec-sim.de, in which he explains that the big secret about Fukushima is that the true source of the massive radiation releases could have been the spent fuel pool of #4 which fell dry.
There are plenty of possibilities for the nuclear nightmare flaring up again.
Something very radioactive did come down from Fukushima all the way to Tokyo on March 15, 2011, elevating the radiation level in parts of Tokyo to as high as 17 microsieverts/hour. Citizens weren't told of anything, and those who knew kept silent until much later.
Reactor 2 suppression chamber probably blew up, and something did blow up in Reactor 4 bldg. on March 15. RSMC Beijing says Reactor 3 had the second explosion on March 15. Any, or all could be the source of the massive release.
Sorry miketokyorogers, your wind pattern post is so wrong you should go back to your middle school and learn again. I don't even know where to start.
I can't believe you write for Lew Rockwell.
Given the recent video of the reactor 4 spent fuel pool looking pretty normal, it is less likely that this was the source of a major meltdown/explosion.
That said, the massive damage at reactor 4 is still not that well explained.
Moreover, it is certainly true that the situation at Fukushima remains tenuous and will be that way for decades, because there is no way to quickly fix things.
Anonymous 6:08,
It is JIM Rogers who writes for Lew Rockwell.
Different guy.
JIM Rogers seems to have a good head on his shoulder.
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