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Information × Registration Number 0216U001564, 0112U007508 , R & D reports Title Development of design and technology production of fuel rods and fuel assemblies for subcritical assembly, conduct their tests in justification of reliability and security popup.stage_title Head Krasnorutskyy Volodymyr Semenovich, Registration Date 25-02-2016 Organization "Nuclear Fuel Cycle "Science and Technology Establishment National Science Center "Kharkov Institute of Physics and Technology" popup.description2 At the stage of FA-Kh Preliminary Design for the sub-critical assembly there was developed design documentation and a Preliminary Design Concept Note describing the fuel rod and fuel assembly design and main manufacturing technologies, as well as calculation and research results to substantiate selection of the fuel rod and FA-Kh option. 10. Fuel rod and fuel assembly designs with fuel materials in the form of dispersion fuel Al +UO2 and UO2 ceramic pellets with a 235U enrichment of 4.95-5.10% were studied. Fuel rod design documentation was developed. 11. Fuel assembly designs with 6 and 7 fuel rods were studied. Design documentation for the FA-Kh with 6 fuel rods proposed for elaboration at the Advanced (Engineering) Design stage was developed. 12. Structural materials were selected, studied, and tested to substantiate their use for fuel rod and fuel assembly elements: - structural material of the fuel rod cladding - zirconium alloy E110; - structural material of the fuel assembly skeleton - stainless steels 08Kh18N10T and 12Kh18N10T; - fuel materials in the form of Al + UO2 pellets with dispersion systems and ceramic UO2. 13. We worked through the main process operations and control methods for manufacturing of UO2 pellet fuel with a diameter of 7.57 mm and a height of 8-10 mm (preparation of powders, press mixture, pressing with a binding agent, sintering, dimension control, density control, oxygen coefficient control) and developed a process instruction "Manufacturing of Uranium Dioxide Pellets" P515-01 TI. 14. We worked through the main process operations and control methods for manufacturing of container-type fuel rods with the pellet fuel (welding of the cladding and end plugs, loading the fuel rod with fuel pellets and filling with helium, fuel and fuel rod weight control, fuel rod geometry control, visual control, weld joint sealing control, and overall fuel rod control). Electric-arc welding with a tungsten electrode in a guaranteed protective atmosphere was selected as the main fuel rod sealing method and the optimum welding parameters were identified. 15. We studied the selected structural materials of fuel rods and FA-Kh, as well as FR and FA weld joints to predict their long-term performance. Two materials were considered and studied as the structural material of the FA-Kh skeleton - E110 zirconium alloy and Kh18N10T stainless steel. We worked through the main operations on manufacturing of the FA skeleton structural elements, as well as skeleton and FA assembly technology (manufacturing and close-fitting the parts, selection of the technology for connecting the skeleton parts, and assembly and securing of fuel rods in the FA). Several options of parts and their connection were considered, the best ones were further elaborated, and a pilot skeleton and one design of the FA-Kh was manufactured using steel 12Kh18N10T as the structural material. 16. The FA-Kh design described in the Technical Proposal was optimized. To ensure FA-Kh compatibility with the reference WWR-M2 FA in the case of their simultaneous use in the mixed sub-critical assembly core, their hydraulic parameters were equalized by increasing the flow area in the FA-Kh top grid. 17. Corrosion tests were done on samples of cladding tubes and weld joints with the end plugs of E110 fuel rods after machining and chemical polishing. The oxide films, including their outer layers formed at temperatures in the range of (50...350) C, have high mechanical strength parameters. According to gravimetric data and oxide film examination, the machined and chemically polished samples have high corrosion resistance. 18. Long-term prediction of E110 sample corrosion kinetics based on experimental data obtained in the course of this work, demonstrates that the E110 corrosion rate in the sub-critical assembly coolant environment is very low. The E110 and weld joint material samples, both with a mechanically treated and a chemically polished surface, have a sufficient corrosion resistance margin for the sub-critical assembly design operation period. 19. A study of corrosion compatibility of the aluminum alloy SAV-1 with Kh18N10T-type stainless steel and zirconium alloy E110 in deionized water at a temperature of 200 C for the duration of 150 hours demonstrated that the samples of contact pairs SAV-1/E110, which electrically contact with each other, did not reveal any significant changes in the SAV-1 appearance. For the contact of SAV-1 and Kh18N10T samples, the aluminum alloy had a higher degree of oxidation, which is testified to by a lighter oxide film. An overview of reference sources points to a possibility of galvanic corrosion of aluminum and its alloys as a factor of certain conditions. Therefore, research should continue, since corrosion of aluminum alloys in high-purity water is a complicated process and depends on a great number of interdependent factors, whose impact on SAV-1 alloy stability needs to be identified and taken into account during design, implementation, and operation of components of the sub-critical assembly's core internals. 20. There were completed nuclear, thermal physics, hydraulic, mechanical, and strength analyses to substantiate selection of materials, reliability, and performance of the developed fuel rod designs with UO2 fuel and E110 cladding for normal operating conditions of fuel rods, fuel assemblies and sub-critical assembly core taking into account the results of studies and developments completed at the stage of Preliminary Design. The calculations demonstrated high strength and thermal physics reliability and structural integrity of the FA-Kh fuel element within the design operation time of 43,800 effective hours with a maximum linear thermal power of 2.36 kW/m. 21. Samples were subjected to a number of studies and tests to substantiate the use of materials, FR and FA component manufacturing technologies, and predict their performance. 22. It is recommended that the following areas be further pursued at the Advanced (Engineering) Design stage: - develop and substantiate the use of fuel rods with UO2 pellet ceramic fuel; - develop a FA with 6 fuel rods; - substantiate selection of the FA structural material to exclude electrochemical corrosion of materials in the sub-critical assembly core. Product Description popup.authors Абдулаев А.М.о Бєлаш М. Грицина В. Красноруцький Володимир Семенович Кулиш Г. Остапов А. Слепцов О. Солдатов С. Татарінов Володимир Романович Чернов І. Черняева Т. popup.nrat_date 2020-04-02 Close