Nuclear reactor question

[SMF]

I get a small e-mail newsletter, What's New, from Bob Park (U. of Maryland physicist). In his discussion of what happened at the reactors in Japan he states the following regarding the hydrogen explosion-

 

"A hydrogen bubble is explosive only when mixed with a critical level of oxygen. During the 1979 Three-Mile Island accident, it was feared that a large hydrogen bubble in the containment dome would explode rupturing the building. It did not happen, but I have repeatedly urged that a tuft of "platinum wool" always be attached at the high points of nuclear containment buildings where hydrogen bubbles would be expected to collect. The platinum would catalyze the oxidation of hydrogen back to water before the mixture reaches an explosive level. The one-time cost would be trivial."

 

This suggestion seems very simple. Can someone evaluate this claim? SM

Edited April 2, 2011 by SMF

[swansont]

I don't see any downside right off. Platinum has a high melting point.

[insane_alien]

I can see a downside.

 

Yes, a one time installation at the time of construction would be trivial.

 

however, catalysts foul up really easily This isn't much of a problem when its just water but your primary coolant loop (which this catalyst will be in) will be full of fission products such as iodine and caesium among others. these, and their decay products will fould the catalyst and inactivate it.

 

to replace the catalytic converter would likely require a shutdown.

 

I think a better solution would to attach a simple flare system (well, maybe not quite as simple as a petrochem flare). I suppose you'd need to have it enclosed to prevent radiation release but its better to burn the threat in a controlled manner than have it explode on you.

[John Cuthber]

I foresee a different problem.

A hydrogen escape that met a tuft of platinised glass wool ( which is what the stuff is really made from) would explode.

Initially the reaction would take place on the surface of the Pt, but that reaction generates a lot of heat. The Pt would get hotter until it ignited the gas.

This was used many years ago ( before they had reliable matches) as a fire lighter.

[ydoaPs]

This isn't much of a problem when its just water but your primary coolant loop (which this catalyst will be in) will be full of fission products such as iodine and caesium among others. these, and their decay products will fould the catalyst and inactivate it.

Fission products are supposed to stay inside the cladding.

[swansont]

I can see a downside.

 

Yes, a one time installation at the time of construction would be trivial.

 

however, catalysts foul up really easily This isn't much of a problem when its just water but your primary coolant loop (which this catalyst will be in) will be full of fission products such as iodine and caesium among others. these, and their decay products will fould the catalyst and inactivate it.

 

to replace the catalytic converter would likely require a shutdown.

 

I think a better solution would to attach a simple flare system (well, maybe not quite as simple as a petrochem flare). I suppose you'd need to have it enclosed to prevent radiation release but its better to burn the threat in a controlled manner than have it explode on you.

 

The Pt would be in the containment building, but not inside the reactor pressure vessel.

 

I foresee a different problem.

A hydrogen escape that met a tuft of platinised glass wool ( which is what the stuff is really made from) would explode.

Initially the reaction would take place on the surface of the Pt, but that reaction generates a lot of heat. The Pt would get hotter until it ignited the gas.

This was used many years ago ( before they had reliable matches) as a fire lighter.

 

That's the goal, though. To light it before large amounts build up.

[John Cuthber]

By the time it reaches the roof, you already have a significant amount of it and it is mixed with air. If you ignite that you will have an explosion.

[swansont]

By the time it reaches the roof, you already have a significant amount of it and it is mixed with air. If you ignite that you will have an explosion.

 

But if you wait until you release even more, you have a bigger explosion.

[insane_alien]

Fission products are supposed to stay inside the cladding.

 

yes, and the majority do but it is common knowledge that the primary coolant almost always contains fission product.

 

Its a high temperature system, there is going to be some diffusion through the cladding whether you like it or not.

 

swansont, i didn't realise the plan would be to have the catalyst outside the reactor.