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CRAs for SMRs
Interest in SMRs ( small modular reactors ) is on the rise in governmental circles , at corporate level and even amongst environmental bodies . High time for SSW to investigate materials options for SMRs .
By KCI Editorial
The use of corrosion resistant alloys in conventional nuclear power plants ( NPPs ) is well established and documented , as evidenced by a quick visit to the websites of stainless steel mills and stockists . Hence Outokumpu , which has been supplying the nuclear industry from the 1960s onwards , notes that ‘ austenitic stainless steels in both standard grades and special grades to nuclear specifications are generally used in reactors . Outside the nuclear island duplex grades are growing in popularity . Stainless steel also plays a key role in ensuring the secure , longterm storage of nuclear waste ’. Alleima also offers specialized materials to the nuclear power sector . For example , zirconium alloy nuclear fuel cladding tubes . To date , well over 60,000,000 meters of nuclear fuel tubes have been supplied to more than 100 reactors worldwide .
Meanwhile , a blog post by Corrotherm highlights the potential of nickelbased alloys such as Inconel 600 and 625 . With properties including high strength , excellent corrosion resistance , resistance to stress cracking and good pitting resistance , 625 has apparently been used for reactor-core and controlrod components . Both austenitic and ferritic stainless steel can be found in a typical reactor , according to a Special Piping Materials ’ blog item , although ‘ austenitic stainless steel ( mainly 304L and 316L grades ) is often the top choice for operators and engineers as it thought to be the most effective in hot and corrosive environments ’. Noteworthy advantages of austenitics include high corrosion resistance to oxidising media , relatively easy to decontaminate , excellent impact resistance ( even in sub-zero temperatures ), easy to weld and fabricate , and ready availability . Montanstahl too sees plenty of applications of 304L and especially 316L , such as for containment vessels , piping systems , fuel rods , storage tanks and also structural components . Further , many companies stress that the presence of cobalt ( a trace element in nickel deposits ) in alloys can create a major challenge for nuclear plants as it transforms into a highly radioactive isotope . Over time , this can create a risk for maintenance technicians . When preparing alloys for use in nuclear power plants , nickel is therefore sourced from deposits that naturally have very low cobalt contents .
Materials research Looking for more specific information as regards the ( potential ) use of stainless steels in SMRs , this magazine quickly
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