Butterfly valve failure causing Nuclear Submarine sinking 2

Dear All,
maybe I'll go off the Forum topics, but I'd like to draw your attention on something it happened to me to read in these almost-summer-holiday days...

I'm talking about "The Hunt for Red October" novel by Tom Clancy*, where the sinking of the fictional Soviet submarine "Politovskij" is described.
It found interesting to read how the imminent cause for the nuclear reactor explosion (in the writer's tale) was the breakdown and drifting of a butterfly valve part in a refrigeration circuit...!
The various steps leading to the incident are described in details: well, I feel that is just... techno-babble**, more than a realistic scenario; but I would like to know the opinion of the other Members who have read the book...
;-)

This curiosity arises also because, unluckily, I've only got the Italian translation of the novel, at the moment, a translation that seems to me very inaccurate, especially from the technical standpoint: so the part of the valve which cracked and teared away is called "àncora della valvola" = "valve anchor"...? (Just one more example: I suspect that "computer chips" was translated with "coriandoli dell'elaboratore", where "coriandoli" means the small bits of colored paper usually thrown around during carnival parties...!)


Thanks for your attention, 'NGL

- - - - - - -

* see:

http://en.wikipedia.org/wiki/The_Hunt_for_Red_October

** see:

http://en.wikipedia.org/wiki/Technobabble

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[zdas04]

I don't have any Itallian, but I've read the book (actually several times) and found the reactor failure you mention to be credible in the original. I don't know why anyone would use a butterfly valve in critical on/off service, but I know that sometimes they do. As I recall the valve was in the main cooling loop which might be called a "refridgeration" loop in a translation, but I've never heard it called that for primary cooling of a reactor (usually I see the term used for loops that include phase change).

Maybe someone with direct experience in Soviet submarine design will address your more specific issues, but with experience in U.S. submarine power cycles I found it credible.

David

 

[NGiLuzzu]

David,
I don't have the book here in my office now (it's at home), but - as far I can remember - yes, the valve was in a circuit containing both steam and liquid water (during the reactor operation); but I don't know if its function was on/off or throttling.

In addition, I recall it was made of titanium (and Clancy develops some considerations about the thermal and mechanical resistance of such a metal, in comparison with the stainless steel of other components of the same circuit...).

Thank you very much for your contribution!!

Ciao, 'NGL

 

[BigInch]

Young's Modulus of Titanium is about half that of steel. Makes for about twice the expansion with pressure. I think its only advantage is strength/weight ratio. Something which, to my limited knowledge, is not a particular advantage on a submarine.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[NGiLuzzu]

Some more information:

- the episode in object is narrated in the chapter entitled "Eighth Day (December 10th, Friday)";

- the butterfly valve seems to be a 4" one installed on a 6" stainless steel pipeline;

- the valve is closed at the moment of failure, and the component that comes adrift ("anchor" as per the approximative Italian translation) is evidently the valve disc, even if the valve stem is not mentioned (while the seat ring is)...



As far as I can understand, the causes for valve failure were:

- the mechanical vibration and fluid mass oscillations (approaching to a system resonance frequency, and mainly due to a high pressure pump which was not repaired to avoid stopping the hunt...), and

- the titanium instability caused by the long exposure to neutron emissions.


Clancy justifies the titanium material selection with the resistance to high temperature corrosion (but it makes little sense to me, also because the rest of the piping is in stainless steel...).

 

[stanier]

Shows you if you want to avoid waterhammer dont use butterfly valves in your system!

Geoffrey D Stone FIMechE C.Eng;FIEust CP Eng

http://www.waterhammer.bigblog.com.au

 

[BigInch]

Good one. I was going to offer a waterhammer explanation. Beat me too it.

Going the Big Inch!

http://virtualpipeline.spaces.msn.com

 

[JimCasey]

Tom Clancy does a better job describing techie stuff than a lot of engineers I know. When he wrote HFRO, he was an insurance salesman.

 

[NGiLuzzu]

Unluckily, the same may not be said about the Italian translator!!
There's no choice, I must get the original English version...
;-)