Abstract: A steam generator, used in a helical coil type steam generator for a sodium-cooled fast reactor which has heat transfer tubes of a double-wall tube structure, with high heat transfer efficiency and a heat transfer tube damage detection unit that can detect on-line in real-time whether the heat transfer tube is damaged or not. The heat transfer tube of a steam generator for a sodium-cooled fast reactor, includes an inner tube formed with a first material; an outer tube formed with a second material that is in close contact with the inner tube and which has a thermal expansion coefficient less than that of the first material; and a plurality of helium flow grooves formed between the inner tube and the outer tube along a lengthwise direction of the heat transfer tube for flowing helium gas.

Abstract: A steam generator, used in a helical coil type steam generator for a sodium-cooled fast reactor which has heat transfer tubes of a double-wall tube structure, with high heat transfer efficiency and a heat transfer tube damage detection unit that can detect on-line in real-time whether the heat transfer tube is damaged or not. The heat transfer tube of a steam generator for a sodium-cooled fast reactor, includes an inner tube formed with a first material; an outer tube formed with a second material that is in close contact with the inner tube and which has a thermal expansion coefficient less than that of the first material; and a plurality of helium flow grooves formed between the inner tube and the outer tube along a lengthwise direction of the heat transfer tube for flowing helium gas.