Relatively new to this. Heard Barry Brook talk recently in Melbourne. A follow up question having heard his talk. I see that some people challenge the use of liquid sodium due to it reacting when exposed to water (and some say air). Has there been industrial scale experience of liquid sodium circuits used to generate steam? So do we know enough about the materials selection and long term mechanical reliability to make accurate assessments of running cost and % up time?
Post by QuarkingMad on Aug 18, 2012 13:47:57 GMT 9.5
In the event of something going wrong the Monju reactor in Japan had an incident where liquid sodium did leak (from secondary coolant loop, i.e. non radioactive) it did burn quite hotly ~700C.
BUT, remember in high school chemistry when the teacher put the block of sodium in water? It reacted very quickly and then nothing.
This is what happened at Monju. It burnt very quickly and once the reaction finished it solidified into 3 tonnes of Sodium metal (other reports say 700kg). IIRC the leak was sealed from the solidification. Add into that the material properties fo the metals around it and a very quick 700C fire may not do as much damage as first though. It only warped, not failed, surrounding steel structures.
Yes it will react. But it does it very quickly and can (reliant on the conditions) end up fixing a leak. Also an operator would be stupid not to situate fire retardant countermeasures in these areas. From the following video of Monju it looks like they had one (the white powder substance over everything). You can see a hardened sodium pile near the end of the video when they look to the right under a large pipe, with the pile situated near a wall (6.13 in video).
A lot of the panic seems to stop at the "sodium reacts violently" observation without going into too much detail of the chemistry or material properties of the reaction.
Since this has happened and the investigation found the fault, poor welding and oversight, operators will look to neutralise this threat in the future. Airline industry does this very well i.e. Trent 900 engine failure (on a Qantas A380) in 2010 and subsequent fix.
Last Edit: Aug 18, 2012 13:48:22 GMT 9.5 by QuarkingMad
The two power reactors now running, one each in France and Russia, are using sodium coolant. The two power reactors now under construction, one each in Russia and India are also being constructed to use sodium. On the other hand, the reason the US,UK and many other countries have discontinued fast reactor development, is sodium fires. It can, therefore, be said that sodium is quite reliable till the fear sodium fires grips your mind. A secondary coolant of molten salts or some other safer coolant should therefore be introduced as early as possible.