Westinghouse Electric Corporation

The United States of America As Represented by the United States

Sidney Diamond

Arthur F Rowcliffe

Melvin L Bleiberg

John A Spitznagel

Ram Bajaj

An essentially gamma-prime precipitation-hardened iron-chromium-nickel alloy has been designed with emphasis on minimum nickel and chromium contents to reduce the swelling tendencies of these alloys when used in liquid metal fast breeder reactors. The precipitation-hardening components have been designed for phase stability and such residual elements as silicon and boron, also have been selected to minimize swelling. Using the properties of these alloys in one design would result in an increased breeding ratio over 20% cold worked stainless steel, a reference material, of 1.239 to 1.310 and a reduced doubling time from 15.8 to 11.4 years. The gross stoichiometry of the alloying composition comprises from about 0.04% to about 0.06% carbon, from about 0.05% to about 1.0% silicon, up to about 0.1% zirconium, up to about 0.5% vanadium, from about 24% to about 31% nickel, from 8% to about 11% chromium, from about 1.7% to about 3.5% titanium, from about 1.0% to about 1.8% aluminum, from about 0.9% to about 3.7% molybdenum, from about 0.04% to about 0.8% boron, and the balance iron with incidental impurities.

Alloys for a liquid metal fast breeder reactor

An alloy consisting essentially of from about 14% to 19% chromium, from 25 to 35% of nickel, from about 2% to 3% molybdenum, from about 0.1% to 1% of silicon, up to 0.5% of manganese, from about 0.03 to 0.05% carbon, up to about 0.01% sulfur, up to about 0.01% of phosphorus, up to 0.01% boron, up to about 0.01% oxygen, up to about 0.02% nitrogen, small amounts of incidental impurities, and the balance being iron, the alloy having an N.sub.v (average electron vacancy number) value of between 1.6 and 2.8, has an unexpected combination of properties enabling it to be formed by hot and cold working and heat treatment into components and members particularly suitable for use in nuclear reactors wherein the components are subjected to molten sodium, where the corrosion of the surface of the alloy is not in excess of the order of 1 to 2 mils per year, and the alloy exhibits low swelling when exposed to intense radiation, while exhibiting good physical properties at temperatures of up to 1325.degree. F. Worked and heat treated alloy members are usable as fuel cladding, grid supports, ducts and other sodium contacting in-core components that may be spaced in close predetermined relationship to ensure high reactor performance, particularly in breeder reactors, for the desired useful life thereof.

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Monroeville, PA, United States of America

Sidney Diamond