Patent Number: 048636827
Section: claims

1. A stainless steel alloy composition for service exposed to irradiation, having resistance to irradiation promoted stress corrosion cracking and reduced long term irradiation induced radioactivity, consisting of a low carbon content austenitic stainless steel alloy composition comprising about 18 to 20 percent weight of chromium, about 9 to 11 percent weight of nickel, about 1.5 to 2 percent weight of manganese, a maximum of about 0.04 percent weight of carbon, a minimum of about 14 times of the carbon percent weight contents of a combination of niobium and tantalum together with the niobium of the combination limited to about 0.25 percent weight of the alloy composition, and the balance of the composition comprising iron with only incidental impurities. 2. The stainless steel composition of claim 1, wherein the alloy composition contains carbon within the range of about 0.02 to about 0.04 percent weight. 3. The stainless steel composition of claim 1, wherein the alloy composition contains tantalum in amounts up to about 0.4 percent weight. 4. The stainless steel composition of claim 1, wherein the alloy composition contains a combination of niobium and tantalum together in amounts of at least about 0.28 percent weight. 5. A stainless steel alloy composition for service exposed to irradiation, having resistance to irradiation promoted stress corrosion cracking and reduced long term irradiation induced radioactivity, consisting of a low carbon content austenitic stainless steel alloy composition comprising about 18 to 20 percent weight of chromium, about 9 to 11 percent weight of nickel, about 1.5 to 2 percent weight manganese, a maximum of about 0.04 percent weight of carbon, a minimum of about 14 times of the carbon percent weight contents of a combination of niobium and tantalum together with the niobium of the combination limited to no more than about 0.25 percent weight of the alloy composition, a maximum of about 0.005 percent weight of phosphorus, a maximum of about 0.004 percent weight of sulfur, a maximum of about 0.03 percent weight of silicon, a maximum of about 0.03 percent weight of nitrogen, a maximum of about 0.03 percent weight of aluminum, a maximum of about 0.01 percent weight of calcium, a maximum of about 0.003 percent weight of boron, a maximum of about 0.05 percent weight of cobalt, and the balance of the alloy composition comprising iron with incidental impurities. 6. The stainless steel composition of claim 5, wherein the alloy composition contains carbon within the range of about 0.02 to about 0.04 percent weight. 7. The stainless steel composition of claim 5, wherein the alloy composition contains tantalum in amounts up to about 0.4 percent weight. 8. The stainless steel composition of claim 5, wherein the alloy composition contains a combination of niobium and tantalum together in amounts of at least about 0.28 percent weight. 9. The stainless steel composition of claim 5, wherein the alloy composition contains a combination of niobium and tantalum together in a maximum amount of about 0.65 percent weight, with the niobium in a maximum amount of about 0.25 percent weight. 10. A stainless steel alloy composition for service exposed to irradiation, having resistance to irradiation promoted stress corrosion cracking and reduced long term irradiation induced radioactivity, consisting of a low carbon content austenitic stainless steel alloy composition comprising about 18 to 20 percent weight of chromium, about 9 to 11 percent weight of nickel, about 1.5 to 2 percent weight of manganese, about 0.02 to about 0.04 percent weight of carbon, a minimum of about 14 times of the carbon percent weight contents of a combination of niobium and tantalum together and a maximum amount of about 0.65 percent weight of said combined niobium and tantalum with the niobium in a maximum amount of about 0.25 percent weight of the alloy composition, a maximum of about 0.005 percent weight of phosphorus, a maximum of 0.004 percent weight of sulfur, a maximum of about 0.03 percent weight of silicon, a maximum of about 0.03 percent weight of nitrogen, a maximum of about 0.03 percent weight of aluminum, a maximum of about 0.01 percent weight of calcium, a maximum of about 0.003 percent weight of boron, a maximum of about 0.05 percent weight of cobalt, and the balance of the alloy composition comprising iron with incidental impurities.