Japan Earthquake: Nuclear Plants at Fukushima Daiichi

Click For Summary
The Fukushima Daiichi nuclear plant is facing significant challenges following the earthquake, with reports indicating that reactor pressure has reached dangerous levels, potentially 2.1 times capacity. TEPCO has lost control of pressure at a second unit, raising concerns about safety and management accountability. The reactor is currently off but continues to produce decay heat, necessitating cooling to prevent a meltdown. There are conflicting reports about an explosion, with indications that it may have originated from a buildup of hydrogen around the containment vessel. The situation remains serious, and TEPCO plans to flood the containment vessel with seawater as a cooling measure.
  • #14,011
http://www3.nhk.or.jp/news/genpatsu-fukushima/20130625/0730_tritium.html Seawater samples taken on 21 June 2013 in the northern part of the harbour were found with 1100 Bq/l of tritrium instead of around 100 Bq/l until last April. Although this is 50 times lower than the legal maximum level, this raises the concern that contaminated groundwater may be leaking into the sea. Tepco says the reason for the concentration rise is still unknown.

http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/2013/images/2tb-east_130625_02-e.pdf Tritium Analysis Results of Seawater in the Port at Fukushima Daiichi NPS
 
Engineering news on Phys.org
  • #14,012
Last edited:
  • #14,013
Your PDF reader seems to have not parsed the symbol for micro in front of the dose given (in microsieverts/h)
 
  • #14,014
Pf... Bummer.
Thanks.
 
  • #14,016
  • #14,017
Bandit127 said:
Do we think this is groundwater contaminated in the original accident now slowly making its way down to the sea?

Err... no. It has to be cooling water injected some time after the accident, which is leeching out from the cores in some way or another.

Its origin is rather inconsequential anyway...
 
  • #14,018
Are we perhaps measuring the diffusion rate of the plume of radioactive material from the damaged reactors?
I had thought that the initial plan was to keep the reactor area water level slightly below that of the surrounding area, because that would ensure ground water flows would be into, not out of, the contamination zone.
What I have no insight into is what is the diffusion rate of the various contaminants from the reactor area. That process will gradually spread the contamination, even against an inflow, because the inflows tend to be localized, while diffusion works everywhere. However, faster inflows help limit diffusive outflows.
It is probably true that TEPCO had expected to dump the treated water fairly quickly, in order to have space available for an aggressive water recirculation treatment program. That they are currently stuck storing huge volumes of basically clean water was predictable, but only in Japan. The result I believe has been that water processing has been slowed for want of storage space and that the contamination has spread more rapidly, because the rate of water inflow into the reactor area has been reduced by the slower water treatment withdrawals.
Can anyone with better physics know how that I confirm this, or put me straight if this is false?
 
  • #14,019
I fail to understand why water is stored instead of being processed by evaporator and discharged in the ocean.
Are there other isotopes beside tritium which won't be separated by distillation?
 
  • #14,020
Masao Yoshida Passes Away

Masao Yoshida, TEPCO Executive Officer (former Plant Chief of Fukushima Daiichi Nuclear Power Station), passed away aged 58, at 11:32AM on Tuesday, July 9 at a hospital in Tokyo due to esophageal cancer. He had been battling the disease for some time.
[...]


From first TEPCO press statement, 9 July 2013 (http://www.tepco.co.jp/en/press/corp-com/release/2013/1228822_5130.html).

We will remember that guy.
 
  • #14,026
  • #14,027
zapperzero said:
Any idea how much it was before the steam?
EDIT: google translate says it's the shield plug area. So the steam could be coming from the RPV.

The whole press release translated:
July 18, is the follow-up about what it was confirmed that the Unit 3 reactor building 5 floor near the center from (equipment storage pool side), steam is in the air.

I will inform you (July 23), so we conducted a radiation dose rate measured in the vicinity of the (whole shield plug) today.

The results of measurement of the 25 locations of the portion near the maximum value 2170mSv / h, a minimum 137mSv / h, the radiation dose rate of the place where it has been confirmed steam was 562mSv / h.

We will continue to watch the situation.

Seems to me like the steam is not carrying radiation with it.
 
  • #14,028
Bandit127 said:
Seems to me like the steam is not carrying radiation with it.

Based on what?
 
  • #14,029
Bandit127 said:
Seems to me like the steam is not carrying radiation with it.
How could that be? In the weeks after the meltdown they had a lot of "steam" coming out, and they got the whole shield plug activated. Here's more data (of today):
http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_130724_05-e.pdf

Seems rather they have a (one?) hotspot that occasionally, unpredictably comes in contact with water. That they cannot find with the remaining thermometers. And a containment that is incontinent not only at the bottom but also at the top (not really a new observation). Worst is the message that no plant parameters have changed. Steam was "found" on 18 July, so what happened before?

This is not what a "cold shutdown" should look like.
 
  • #14,030
zapperzero said:
Based on what?
Less radiation where the steam was coming from than the maximum they found.
 
  • #14,032
Bandit127 said:
Less radiation where the steam was coming from than the maximum they found.

It does not follow.
 
  • #14,033
  • #14,035
triumph61 said:
TEPCO's spokesman said the steam coming out of Reactor 3 in March 2011 after the explosion was from inside the Containment Vessel, and that is known to everybody.
http://ex-skf.blogspot.de/2013/07/fukushima-i-nuke-plant-reactor-3s-steam.html

So 2 1/4 years the TEPCO PR dept. found it feasible (without "losing honor") to admit what, at that time, indeed everybody understood. We then might prepare for lots of additional data that was supressed then.

On the "rainwater theory" here's a nice comment from the same Ex-SKF thread:
mscharisma said:
The fire-breathing dragon explanation for the rising steam is at least as plausible as the "rain hitting the 40 degree containment cap" explanation. My vote goes to the dragon.
*mscharisma*
July 25, 2013 at 7:43 AM

Then, even as rainwater sickers down it will eluate radioactive substances, when heated (to 40 °C!) go to gas phase, the steam will carry more particles and droplets out (most will condense though), and the expelled stuff will not be radioactive? There are two things that are not consistent.

a) The 40 °C thing. But TEPCO claims it's all cold shutdown, right?

b) The remarks by Bandit127 on the non-radioactive steam.
Bandit127 said:
Seems to me like the steam is not carrying radiation with it.
 
  • #14,036
ronaldkr said:
heated (to 40 °C!)

this is the one bit that is very grating
outside temp ~20°, humidity ~90%, but somehow water heated to 40° manages to turn into observable amounts of steam. How does that work?
 
  • #14,037
from what i understand, new temperature measures are 30.7° - 40 m above the roof - , and 34.3° - 5 m above - (Infrared thermography of the location of the steam on July 24, 2013). I'm not sure how they came up with that 40° thing they used in the first press release about the steam.

Today Tepco in a new press release stated (from ex-skf translation) :

Mechanism of steam generation

In addition to rainwater seeped in from a gap in the shield plug and warmed by the Containment Vessel head, there is an observable difference(3 m3/hr) between the amount of nigrogen gas being injected into the Reactor Pressure Vessel and Containment Vessel (16 m3/hr) and the amount of nitrogen gas being extracted (about 13 m3/hr), and it is possible that this gaseous body (3 m3/hr) containing enough water vapor is leaking through the Containment Vessel head. We presume that when the vapor leaks through the gap in the shield plug onto the 5th floor of the reactor building, it is chilled by the air which is relatively colder than the vapor, and is visualized as steam.
 
  • #14,038
Ronaldkr - I would like to retract my previous comment. Prompted by other posts I have given this further thought.

Should the steam be carrying radiation, it would deposit it if it condenses. It may condense more favourably somewhere cooler than the place it escapes from and this would explain a higher reading somewhere else.

The fact that Tepco have withdrawn workers from the area while they investigate may be due to the high readings (2.0 Sv/hr). It may also be due to them suspecting the steam is carrying radiation. "While they investigate" suggests the latter.

I don't want to believe the fire breathing dragon analogy. But if there is one, it's rear end is down in the water table I think.
 
  • #14,039
  • #14,040
Do they also get a year end bonus for helping to keep Fukushima out of the news until after the elections?
Cynicism aside, is this not the first public sanction imposed on any member of TEPCO management?
 

Similar threads

Fukushima Fukushima Daiichi nuclear disaster discussions
  • · Replies 12 ·
Replies
12
Views
49K
Ukraine nuclear power plant Zaporizhzhia on fire
  • · Replies 41 ·
2
Replies
41
Views
5K
Fukushima Japan Earthquake: nuclear plants Fukushima part 2
  • · Replies 2K ·
60
Replies
2K
Views
450K
Fukushima Are US Nuclear Power Plants Prepared for Earthquakes?
  • · Replies 5 ·
Replies
5
Views
6K
Fukushima Critiques of Fukushima Thyroid-Cancer Study
  • · Replies 2 ·
Replies
2
Views
2K
What if a nuclear power plant loses outside electricity?
  • · Replies 6 ·
Replies
6
Views
20K
Japan Earthquake: Political Aspects
  • · Replies 763 ·
26
Replies
763
Views
274K
Fukushima How will they end the Fukushima disaster?
  • · Replies 38 ·
2
Replies
38
Views
16K
Thoughts on nuclear power and disasters [long, rant/tangenty]
  • · Replies 6 ·
Replies
6
Views
4K
Fukushima The geological issues of the Fukushima Daiichi
  • · Replies 4 ·
Replies
4
Views
11K