TEPCO posted a section in a larger roadmap in Japanese about an investigation into the torus of unit 1 over gas build up concerns. Below is a rough machine translation of the document section.
Update: Fukushima-Diary just posted an NHK video explaining the hydrogen & krypton buildup in the torus. Apparently it has been an issue since April and TEPCO thought they needed to intervene.
For the nitrogen injection to the S / C Unit 1
October 22, Heisei 24
Tokyo Electric Power Co., Inc.
Method of estimation and verification mechanism
Pressure drop ① S / C pressure (← D / W
Due to) lowering of water level and PCV
Water level in the S / C that is reduced,
The top gas in the closed space (water
Iodine, Kr85) is vacuum break device
Discharged to the D / W through the 置管
At the top of the gas ② S / C emissions
When, inland S / C again
Place to rise, stop the spill
Repeat ③ ① ⇔ ②
In order to validate the estimation mechanism, which is filled with nitrogen into the S / C, check the response
2. As a result of the nitrogen injection to S / C (implementation inclusion 9/4)
After the start of inclusion N2, pressure S / C rise
Pressure gauge (S / C is the same as the line inclusion N2
Pene has been removed from the X205)
Pressure D / W minutely rise
N2 is sealed through the X205 Pene
Has been determined that the
With a lag time of about 1 hour, 12
Kr85 concentration, hydrogen concentration is up from at around
No increase in oxygen concentration
Street-estimation mechanism, or S / C
Those that are extruded to D / W from
– The concentration of oxygen in the S / C is almost zero
3. Continuous inclusion of nitrogen into the S / C
For gas retention in the S / C, which is confirmed by nitrogen injection 9/4 last
Carried out by the inclusion of continuous nitrogen purge.
※ root inclusion S / C is the same as when carrying out 9/4
4. The basic idea of the continuous inclusion of nitrogen
The hydrogen concentration in the (PCV is sufficiently low hydrogen concentration in the S / C is about 2% until the estimated
I do a continuous inclusion) until.
Upper limit of the concentration of hydrogen in the PCV is 2%.
From the results of simulation, the nitrogen injection flow rate is 1Nm3
/ and degree h, about one month
Carried out in the period hydrogen concentration (S / C drops sufficiently, 3Nm3
/ increase in degree h).
<Process at the start of nitrogen injection more>
This article would not be possible without the extensive efforts of the SimplyInfo research team
Join the conversation at chat.simplyinfo.org
© 2011-2018 SimplyInfo.org, Fukuleaks.org All Rights Reserved Content cited, quoted etc. from other sources is under the respective rights of that content owner. If you are viewing this page on any website other than http://www.simplyinfo.org (or http://www.fukuleaks.org) it may be plagiarized, please let us know. If you wish to reproduce any of our content in full or in more than a phrase or quote, please contact us first to obtain permission.