×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Three Mile Island - Stuck open PORV
2

Three Mile Island - Stuck open PORV

Three Mile Island - Stuck open PORV

(OP)
I'm doing some reading on the TMI incident.

There were human factors at play, but a critical pilot operated relief valve was also faulted. I've seen this noted in many reports (Rogovin report) as well as all over the net and unfortunately also Wikipedia which everyone references.

What I don't find is what exactly was the mechanical fault of this particular valve. As it turns out there were other failures in plants of similar design in the same valve (from different manufacturers).

I've done what scouring I can do to find out. What do you know about it? As valve designers, it seems like this is the kind of 'learning from history' is a good thing.

RE: Three Mile Island - Stuck open PORV

About a year ago I spoke with someone at Ferris engineering on the matter of failing PORV's. He himself said that the PORV sales have descresed rapidly over the past decade. They are useful in some applications, but I would much rather have a mechanically controlled relief valve than one that uses system pressure. IMHO

RE: Three Mile Island - Stuck open PORV

I think that the TMI relief valve problem was some type remotely activated electrical device instead of a traditional section VIII process or section I safety valve.  The failure issue would be good information.

RE: Three Mile Island - Stuck open PORV

2
You might want to read some of the Nuclear Regulatory Commission documents published at the time. (www.nrc.gov then follow links to > Electronic Reading Room > Document Collections> Generic Communications or > Electronic Reading Room > Document Collections > NUREG Publications).  Ones that you might be interested in are Bulletins 79-05, 79-06 and their supplements, Information Notice 79-016, and NUREG 0578, "TMI-2 Lessons Learned."  These are all available electronically.
You may also want to look at NUREG 0462 "Technical Report on Operating Experience with BWR Pressure Relief Systems",
dated July 1978.  It's mentioned in Generic Letter 79-027.  I couldn't find the NUREG itself in an electronic format.  

However, there is a link on the NRC public website to contact the public document room staff (www.nrc.gov then follow links to > Electronic Reading Room > Public Document Room > Contact the PDR Staff.)  They may be able to provide you a copy or be able to locate it for you.

Just a final word though -- be careful what conclusions you draw from these 31 year old documents about today's components.

Patricia Lougheed

******

Please see FAQ731-376: Eng-Tips.com Forum Policies: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

RE: Three Mile Island - Stuck open PORV

Patricia..

Just curious..... The need for pressure release is still there in the new PWR and BWR plant designs.

Do you know what the design details are for these new valves in the new generation of nuclear plants ?

-MJC

   

RE: Three Mile Island - Stuck open PORV

MJCronin

Not off the top of my head; I'm not involved in new construction at all.

Would you want me to find out (can't promise results as I'm not sure how much is publicly available)?  I think my profile mentions how to get hold of me.

 

Patricia Lougheed

******

Please see FAQ731-376: Eng-Tips.com Forum Policies: Eng-Tips.com Forum Policies for tips on how to make the best use of the Eng-Tips Forums.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources