TEPCO has done nothing but lie about their incompetence and ineptitude since the beginning of this, so their denial is meaningless, and likely not an accurate assessment of the situation.
Operator TEPCO insists there has been no nuclear reaction and that the reactor can be controlled.
Responding to the increase, the operator began injecting 15 tonnes of water an hour into the reactor in a bid to get the temperature down.
TEPCO says it has not detected any xenon gas, which is created when a nuclear reaction has been triggered.
The company suspects that cooling water has not been flowing freely into the the number two reactor, causing the rise in temperature.
Tepco graph shows spike above 90°C at Reactor No. 2 Exactly how high have temperatures gone?
Q: Why has the temperature started to vary widely since noon?
A: We don’t quite know.
Q: When will you get back to the normal operation under the safety regulations?
A: To do it, we have to make sure it is the instrument failure.
Q: Does the instrument failure have to do with the variance?
A: It’s not that the instrument failure started today, but it may have started late January when this thermometer started to behave differently from the other two at the bottom of the RPV.
Q: Why did you start mentioning “instrument failure” only when the temperature started to approach 80 degrees Celsius?
A: We didn’t think it was behaving erratically. The variance of 1 degrees was understood. The trend changed at the end of January. Also, the temperature remained high as more water accumulate inside the RPV, therefore the instrument failure more likely.
A: We want to see if it is possible to have the instrument failure where the temperature drops, instead of going up.
A: The Containment Vessel is still hot and humid, so we have to make sure the other instruments [with temperatures remaining in the 30s?] are working properly. At this point, we don’t have better alternatives.
Q: Why are you increasing the amount of water if you think it is the instrument failure? What do you think of the safety regulations?
A: We have always informed the NISA and followed the safety regulations.
(No answer on why they are increasing water.)
Fukushima No. 2 reactor temperature up to 82C
TOKYO (Kyodo) — Tokyo Electric Power Co. said Sunday the temperature at the bottom of the No. 2 reactor at its crippled Fukushima No. 1 nuclear plant rose further to 82 C, but the reactor has not gone critical.
While the thermometer reading at shortly after 2 p.m. marked a new high since the reactor attained a cold shutdown in December, the utility known as TEPCO said it has confirmed that sustained nuclear reactions are not taking place in the reactor as no radioactive xenon has been detected inside its containment vessel.
TEPCO reported the latest development immediately to the Nuclear and Industrial Safety Agency of the Economy, Trade and Industry Ministry as the temperature exceeded the limit of 80 C designated by the company’s safety regulation for maintaining a cold shutdown, it said.
It is considered desirable to keep the temperature below 80 C, while the bottom of a reactor pressure vessel must be kept below 100 C in a stable cold shutdown, in view of the margin of error of thermometers, according to TEPCO officials.
TEPCO plans to increase the amount of water injected as a coolant by 3 tons per hour and pour 1 ton of boric acid later Sunday to prevent any event of criticality.
…reactor2 heated over 80℃, he tweeted like this below.
Even if it’s true that the heating gauge is broken, we can’t fix it, and what if other 2 gauges got broken too ? I don’t think it’s broken though. I don’t know the distance of the nuclear debris and heating gauge, nor the flow of cooling water but I think it’s likely that only one part gets heated.
and even if it’s actually broken again, I don’t know how it can be broken but breaking wire or problem of a terminal makes it indicate maximum + or – in case of thermocouple thermometer. It can’t be noise either. I wonder if Tepco will try to repro agian..
Only if they haven’t declared cold shutdown, we could treat it in variety of ways as an accident but because Tepco and Japanese government have to keep it lower than 100℃ not to let it deny the state of cold shutdown, knowing it causes additional problems, they are putting boric acid and increasing water amount.
Temperature inside No 2 reactor may have risen to 82C, and Tepco reportedly steps up cooling efforts
Tepco said there was no evidence that the melted fuel inside had reached criticality. The utility reportedly increased the amount of cooling water being injected into the reactor along with a boric acid solution, which is used to prevent the fuel from undergoing sustained nuclear reactions.
Confirmation that the temperature has risen above 80C could force the government to reverse its declaration two months ago that the crippled plant was in a safe state known as cold shutdown.
Cold shutdown is achieved when the temperature inside the reactors remains below 100C and there is a significant reduction in radiation leaks. Given that Tepco assumes a margin of error of 20C, the actual temperature could have risen to 102C.
Plant workers are unable to take accurate readings of the temperature inside the damaged reactor because radiation levels are still too high for them to enter and examine the state of the melted fuel, which is thought to be resting at the bottom of the reactor’s pressure vessel.
The result has been a series of wildly different readings: two other thermometers positioned at the bottom of No 2 reactor showed the temperature at 35C, local media reported.
Tepco said it did not know the cause of the apparent temperature rise, but speculated that it might be due to problems with the supply of coolant or a faulty thermometer.
from the guradian, uk: