1h11m56s20f Liquid Sodium used in Fast-Spectrum Solid-Fuel Breeders is Chemically Reactive TR2016a
Channel: Thorium Remix
Date: 2017-04-28

http://ThoriumRemix.com/ Because the Liquid Metal Fast Breeder Reactor uses liquid sodium as coolant, and because sodium has a higher boiling point than water at atmospheric pressure, the coolant in a liquid metal fast breeder does not need to be pressurized. 

Just got a little tiny thin pipe.

So then- both types of breeder reactors, the Liquid Metal Fast Breeder and the Molten Salt Breeder, can avoid the cost and complexity associated with containing pressurized water coolant which may flash to steam. 

However, the chemical stability of Molten Salt coolant, and the ability of Molten Salt to secure radioactive isotopes within strong chemical bonds is not shared by sodium.
 
It's stored under an oil, to stop air or moisture getting on it.

Reacts very, very quickly with air and also with water.

The hydroxide is a white crust on the outside.

Alright, go.
Booooo.

They built the reactor and put it in a sub and ended up cutting the reactor out of the sub and putting a LWR in it.

They became disenchanted with sodium cooling rather quickly.

What happens if there's a leak? Sodium reacts with the air and the water.

Well you haven't got air next door to your sodium surfaces. It's inerted.

With Liquid Metal Fast Breeders, the advantage of a coolant operating near atmospheric pressure must be weighed against the use of that same coolant which also reacts rapidly to air at high temperature, and violently to water at any temperature.