The Clinch River Breeder Reactor Plant steam generator that transfers the heat from the sodium system to the high-pressure system must maintain integrity and separation of the two fluids. The construction material used for the tubing and tubesheet is high-purity 2¼ Cr—1 Mo alloy steel. To attain confidence in successful manufacturing of the evaporator and superheater modules, key development activities are under way (a) to procure high-quality wrought materials, (b) to assure proper assembly (with emphasis on welding), and (c) to assure that adequate nondestructive testing methods are available to examine the units.