March 24th, 2011 – New information from AEC casts doubt on GE’s analysis of venting and hydrogen explosions at Fukushima Daiichi

From: Kelly, John E (NE)
To: DL-NERT-AII
Sent: Fri Mar 25 00:10:21 2011
Subject: FW: Hydrogen

Here is new information from the Japan AEC. I know GE thought that the vented via a wetwell line, but this is a different interpretation. This scenario means that the head bolts stretched, which GE didn’t think was what happened. I will need the pressure histories for the first multiple hours of the situation (especially In the containment) in order to provide a response. Have we plotted that info yet?

 

From: Akiraomoto [mailto:l b)(6) -
Sent: Thursday, March 24, 2011 11:46 PM
To: Kelly, John E (NE)
Cc: Lyons, Peter; [email protected]; Binkley, Steve; SCHU; Poneman, Daniel; Connery, Joyce; [email protected]
Subject: Re: Hydrogen

Dear Mr. John Kelly,
Akira OMOTO, a Commissioner in the AEC is writing to you.

Thank you for sending your note.

I thought that the following points need to be considered;

1) SAM (Severe Accident Management) procedure and modifications were finished in the 90’s including containemnt “hardened” scrubbing venting to the main stack (NYT article is wrong) via wetwell air space, makeupo water using fire protection system from large size portable water storage tank, bus inter-connection to other units (this worked very well in unit 5 and 6 since one EDG continued operation), and others.

2) All the three units (IF] -3) experienced containment overpressure in the early phase of the accident, which caused excessive leakage from flange, ailocks and other peentrations. Hydrogen produced by Metal Water reaction in the core damage process must have escaped to the reactor building via this containment leakage path and accumulated on the top and caused deflagration/detonation there. Further, containment was steam inerted and a large fraction of hydrogen escaped -by “hardened” venting.

3) Still radiolysis of water is ongoing and produces hydrogen/oxygen in the containment (hopefilly in the RPV). thus, still the risk of hydrogen deflagration/detonation exists, in my view.
Remeber that if lodene and other Halogen elements exist in the water they function to retard or prevent recombination of hydrogen/oxygen.
My paper on hydrogen control in BWR (Nuclear engineering and Design, 2000) discussed this point.

Study is ongoing in TEPCO;
a) to open vent valve of RPV while keeping steam inert conditionm and
b) to send nitrogen or other inert gas to the containment. However, to inject nitrogen containment isolation must be unlocked first and then valve operation must be done in an extremely harsh environment.

akira OMOTO

 

 

AEC Hydrogen Analysis – Pages From C142015-02B
Related Articles on Page 2…

Useful news and research on the energy and electricity industries.

About author
Our FOIA archives feature collected and sorted FOIA documents, and are sub-categorized by event, topic, importance, and type.Email chains are extracted and published according to date.Press releases are archived by date of publication.Presentation materials and pdfs are summarized and displayed in whole.Each post is titled with the date of transmission of that particular FOIA combined with the subject of the message.
Read More About , ,
2 total comments on this postSubmit yours
  1. joybusey@gmail.com'

    Huh. GE of course must have known better, as their venting system is SUPPOSED to go to the vent stack, not into the ambient atmosphere of the Rx building. If hydrogen blew the building sky high, then it didn’t come from that system. Hence had to have come from the head or some other breach of containment.

    Any decent engineer would know this. Arnie Gundersen pointed it out early on. I am semi-amazed AEC claimed ignorance. It’s really not that hard.

  2. captddd@hotmail.com'

    Head bolts stretching under load AND during the BIG Earthquake makes so much sense; especially since once the quake hit the entire metal reactor Assy. probably was stressed well beyond what it was designed for…

    These “head bolts” can be removed and then tested now since the reactors are no longer reactors and just piles of metal scrap…

    I believe that inspectio will prove that they have been stressed well beyond their designed loading; that is IF TEPCO will release the data!

Submit your comment

Please enter your name

Your name is required

Please enter a valid email address

An email address is required

Please enter your message

*

Enformable © 2014 All Rights Reserved

More in NRC, Top Docs - FOIA
fuku3
April 4th, 2011 – Observation requirements to validate an ocean plume modeling effort – NOAA

" In-situ measurements of radionuclides in the ocean are needed to validate and tune the models. These data will provide insight into the important processes associated with the movement of theseparticles throughout the...

Close