Sunday, February 5, 2012

#Fukushima I Nuke Plant Reactor 2: Temperature Has Been Rising at the Bottom of RPV

So much for "cold shut down" and "end of the accident". Maybe the reactor didn't like the endoscopy done in January...

From FNN News (2/5/2012):

福島第1原発2号機の原子炉の温度が、2月2日以降、上昇を続けていて、東京電力は5日未明、原子炉への注水量を増やし、温度が低下するか確認することにしている。

Temperature of the Reactor Pressure Vessel of Reactor 2 at Fukushima I Nuclear Power Plant has been rising since February 2. TEPCO will increase the amount of water being injected into the reactor to see if that lowers the temperature.

2号機の原子炉圧力容器下部の温度は、2月2日におよそ52度だったが、その後、上がり続けていて、5日午前5時の時点で67.4度と、およそ15度上昇している。

The temperature at the bottom of the Reactor Pressure Vessel of Reactor 2 was about 52 degrees Celsius on February 2, but it kept rising. As of 5AM on February 5, it was 67.4 degrees Celsius, 15 degrees increase.

これを受けて、東京電力は5日未明、原子炉への注水量を1時間あたり8.6トンから9.6トンに増やし、温度が低下するか監視するとしている。

On February 5 TEPCO increased the amount of water injected into the reactor from 8.6 tonnes/hour to 9.6 tonnes/hour to see if it lowers the temperature.

原因について東京電力は、現時点で明確にはわからないとしているが、「冷温停止状態」の判断には影響はないとしている。

TEPCO says it doesn't know what is causing the temperature to rise, but says it doesn't affect the decision of "cold shutdown state".

According to the latest plant parameter data from TEPCO, the temperature at the bottom of the RPV of Reactor 2 at 11AM is 68.6 degrees Celsius, up over 1 degrees from 5AM.

By the way, the temperature at the CRD Housing Upper Part, which went up to 142 degrees on January 14, and dropped down to -197 degrees on January 19, is now back up at 124.7 degrees Celsius ("instrument failure", according to TEPCO):

Here's what TEPCO said in the handout for the press on February 4, 2012:

【Unit 2】19:20 on February 3: To improve reliability of water injection to the reactors, the injection line connecting to the reactor injection pump on the hill was replaced with polyethylene pipes and we have been changing the route for reactor injection from feed water system to reactor core spray system in a stepwise manner. After completion of adjusting water flow amount as planned on February 2, tendency of temperature rise at the bottom of PCV was observed. Thus, we changed the injection amount into Unit 2 reactor through feed water system from 2.9 m3/h to 4.9 m3/h and changed that though reactor core spray system from 5.8 m3/h to 3.8 m3/h . As for the temperature rise, the temperature at the upper head of the bottom of PCV has risen to approx. 67.2 ℃ at the highest (as of 4 pm on February 4: reference), but currently, it is approx. 65.1℃*1 (as of 5 pm on February 4). The trend of the temperature seems to be going flat and we will monitor it continuously.

The worker who tweets from Fukushima I Nuke Plant is more worried about Reactor 2 than Reactor 4.

11 comments:

Anonymous said...

Reactor 2 and Reactor 1. One other comment--how does anyone know if the two reactors corium are interacting with each other..or making a layer of corium cojoined. Temperatures going up..not what anyone wants to hear.

Now how can one gage be "broken" when it reports what TECPO does not want to hear..and OK when it does. Is this scientific in any way?

Hélios said...

Hello Ultraman,

As you read, of course, japanese, is there anything interesting in this report ?
http://fukushima-diary.com/2012/02/actual-disaster-report-of-fukushima/

Thank you.

Anonymous said...

Tepco has been on the vicious fireman's water cycle of feed and bleed for nearly 11 months. Fighting nuclear fire with water cannons is an exercise in futility, but it does forestall Armaggedon.

Thank you Japan for being the martyr of the 21st century and proving nuclear energy is neither cheap nor safe. The entire economy of Japan is obviously at risk and that worries the leaders even more so than millions of radiation deaths.

SP

Atomfritz said...

These developments in these black boxes of reactora remain highly interesting.

Corium garbage movement?
Things crashing down, changing water flow paths?
Or another instrumentation failure?

@anon 5:12
The three reactor's coriums don't interact directly, as they are contained in three separate buildings.

netudiant said...
This comment has been removed by the author.
netudiant said...

netudiant said...
Broadly speaking, a more useful definition of cold shutdown would be that the reactors have quit steaming radioactive vapor into the atmosphere. We are still far from that happy day.

Meanwhile, the water temperatures are at best an indirect measure of the situation, as Atomfritz correctly observes.
The main comfort is that the decay heat of the fuel is now down to about a megawatt for the larger reactors and continues to diminuish.
That eases the concerns about some massive new escalation of this disaster.
Of course it is plenty bad enough as is.

It is unsurprising that the workers are more concerned about reactor 2 than 4. Reactor 2 was previously identified as the source of the majority of the radioactive pollution that is hurting Japan.
Reactor 4 was offline with its fuel mostly in the spent fuel pool, which seems to be reasonably intact. I am surprised we hear so little about reactor 3, even though it experienced the largest and most destructive explosion, while fuelled partly with MOX fuel.

arevamirpal::laprimavera said...

From what I understand, radiation levels in Reactor 3 is too high to do anything (such as sending in workers).

Anonymous said...

When are the tepco management going to be gaoled for life? Or simply executed on the spot!

It's well past time to start taking revenge against these bastards. They are destroying the world, kill them!

Anonymous said...

Just read the activity reports on what has occurred to the units 1 -6. And on page 21..read about Unit 6 and 7 Sv/hr. HOPE that is a translation issue..
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110819e2.pdf

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