What not use a proportional relief valve?

[tsutsuji]

There is this talk in the New York Times about venting valves :

But the consensus in the nuclear industry supports the existing systems. Douglas E. True, the president of ERIN Engineering and Research of Walnut Creek, Calif., said: “In some cases you can argue it might be better to have a rupture disk. In other cases, it would certainly be better to have a manually controlled system.” For example, he said, the disk is backed up by a valve that is normally in the open position. If the disk ruptured and there was no electricity, it might be impossible to close the valve, and the venting would be permanent.
http://www.nytimes.com/2011/05/19/science/earth/19nuke.html?partner=rss&emc=rss

What not use a proportional relief valve ?

 

[tsutsuji]

I Found the following comment :

I don't know what happened to pressure release valves. They are opened by excessive pressure and close themselves when the pressure drops. You will find them on your water heater and even simpler versions on a pressure cooker. They were used on the test loops at the Idaho test reactors in the late 60's and presumably still are.
(...)
I'm curious why they aren't used.
http://green.blogs.nytimes.com/2011...eatens-to-blow-its-stack/?partner=rss&emc=rss

So am I.

 

[jlduh]

Very interesting article Tsutsuji, thanks!

All this venting subject is totally unclear in this Fukushima disaster, obviously it's not the primary cause of the disaster but it revealed that a lot of things didn't work as expected ALSO in this department... which ended up making things worse i think.

We will need time and torough expertise to clarify what really happened...