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New Alloys for Nuclear Waste Handling

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Development of Scientific Bases and Technological Aspects of Creation of New Generation Hard Deformation of Cr-Ni Staainless Steels with the High Contents Boron (1,0-1,9% of Weights) on the Basis of Principles of Metallurgy of Atomized Powders of an Alloy

Tech Area / Field

  • MAT-ALL/High Performance Metals and Alloys/Materials

Status
3 Approved without Funding

Registration date
19.07.1998

Leading Institute
All-Russian Scientific Research Institute of Non-Organic Materials named after A. Bochvar, Russia, Moscow

Supporting institutes

  • Institute of Aviation Materials, Russia, Moscow\nNIKIET (Sverdlovsk Branch), Russia, Sverdlovsk reg., Zarechny\nNETRAMM, Russia, Moscow

Collaborators

  • Siemens, Germany, Offenbach am Main

Project summary

PURPOSE of PROJECT

1. Development conceptual approach to creation chrome-nickel stainless steel of austenitic class with high 1.0–1.9 % of weights contents boron and elements of base technology of manufacturing these steels, their remake in thin sheets, strips or pipes.

2. Definition of possibility of creation composite multilayer boron content material on the base of stainless chrome-nickel steel of аustenitic class and evaluation of their characteristics.

3. Experimental of confirm of fitness developped steel for reliability long-duration storage high-level radioactive of fissile materials and nuclear waste, in particular, spent fuel assembly (FA) nucleus reactors.

TECHNICAL APPROACH

With increasing a contents boron adaptibility to manufacture of stainless austenitic chrome-nickel steel is sharply worsenned and for steel containing more 1.2% of weigths boron, make thin sheet product on the traditional processing scheme (melting of ingot with following its hot and cool deforming) becomes impossible. Main reason this is coarsening of structures of ingot and irregular localization boron in the form of nondeformed, non-soluble borides by the size before 200 mm, locating on borders granes.

In the world practical increasing ductility of hard deformation material, basically nickel alloys, attain using methods an granule metallurgy for the fabrication of products. On this scheme melted material atomize in small particals of powder, mainly spherical form, then received powder compacting under high temperatures and pressures in the semifinished item, which then carry to required products, using traditional technologies of processing by the deformation.

Using the principles of metallurgy of atomized powders for аustenitic stainless chrome-nickel steel with the boron must raise its deformation ability, will allow to carry out hot and cool deforming to making sheet or pipes of required size and under more high contentses boron in steel. High homogeneity of composition, which reached on account of mixing powder steel, will allow raises corrosion resistant steel and its mechanical properties.

On the complex of characteristics an using a new material new аustenitic stainless steel with the high contents boron for storage of high level radioactive of fissile material and nuclear waste, in particular spent fuel assembly nucleus reactors, will raise reliability and safety, as well as will increase long-duration storage of nucleus material. However for getting optimum corrosion and mechanical properties at such high contents boron is required correction of chemical composition steel.

In work is also planned carry out corrosion and radiation tests an аustenitic stainless chrome-nickel steels containing before 1.9 % of weight boron. Evaluation of influence of duration of irradiating on characteristics and structure steels will be made on the base of reactor test up to fluence 1017 n/cm2. In the project is provided searching possibility of getting composition multilayer material containing before 1.9 % of weight boron on the base of аustenitic stainless chrome-nickel steel.

EXPECTED RESULTS

1. Making a conceptual approach to making chrome-nickel stainless steel of аustenitic class with high 1.0–1.9 % of weight contents boron and elements of base technology of manufacturing these steels, their remake in thin sheets, strips or pipes.

2. The determination of experimental dependencies of structure and characteristics of material from kinds and main parameters of processing an alloy.

3. Making the mathematical models of main technological process of manufacturing the products from high boron steel (atomization, compaction).

4. Evaluation of influence of irradiating in the reactor up to fluence 1017 n/cm2 and corrosion resistence of new material.

5. Formation of scientifically motivated recommendations for industrial manufacturing items from аustenitic stainless chrome-nickel steel with the boron contents 1.0–1.9 % of weight, including determination of main technical requirements for the specialized equipment.

SCIENTIFIC BENEFIT

For the first time will be studied influences superhigh, about several millions degrees Celsius in a second, speeds of coolling a melt on the structure an chrome-nickel stainless steels with the high boron contents, tracked hereditary changing a structure under following fabrication and installed communication between the structure and properties of material from types and main parameters of processing an alloy.

COMMERCIAL BENEFIT

Using the products from аustenitic stainless chrome-nichel steel for long 50–100 years of compacted keeping spent fuel assembly (FA) of nucleus reactors will allow to abandon to high-priced reprocessing of spent nucleus fuel for the whole storage life, before the appearance of new approaches to salvaging the nucleus wastes.

INDUSTRIAL EVALUATION

Proposed approach will allow to create an industrial pipe production from chrome-nichel stainless steel with the contents boron more than 1,2% of weight, impossible when using a traditional metallurgical technology. Herewith, comparative evaluation of factors of new and traditional technologies, conducted for steels with the contents boron before 1% of weight shows that proposed approach for getting the thin sheet products on the base of principles of metallurgy of atomizing powder raises an output of metal initial ingot in the prepared pipe in four–five time in contrast with the standard processing scheme once. On standard technologies in the pipe will be realized only 10% from initial ingot, on the proposed scheme is expected that output fit will form not less than 40%. On available evaluations in conditions of Russia one pipe cost by the dimension 150–200ґ3–5ґ3000 mm from аustenitic stainless chrome-nichel steel will not exceed 3500 dollars.


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