Abstract:
The present invention relates to a method of manufacturing tubes of zirconium based alloys for usage in nuclear reactors. According to the invention one can achieve good resistance towards general corrosion, improved transversal creep strength and reduced irradiation induced growth by subjecting a .beta.-quenched tube a vacuum anneal in the .alpha.-phase range at a temperature and a time sufficient to obtain an annealing parameter value A in the range 3.4 .times.10.sup.-16 to 3.4 .times.10.sup.-13.
Abstract translation:PCT No.PCT / SE95 / 00749 Sec。 371日期1997年04月17日 102(e)日期1997年4月17日PCT提交1995年6月20日PCT公布。 出版物WO95 / 35395 日期:1995年12月28日本发明涉及一种用于核反应堆的锆基合金管的制造方法。 根据本发明,可以在足以获得退火参数的温度和时间下对β淬灭的管进行α相范围内的真空退火,从而获得对一般腐蚀,改进的横向蠕变强度和减小的辐射诱导生长的良好抵抗力 值A在3.4 x 10-16到3.4 x 10-13之间。
Abstract:
A tube for constituting all or part of a cladding or guide tube for a fuel assembly is made from an alloy containing, by weight, 0.4% to 0.6% of tin, 0.5% to 0.8% of iron, 0.35% to 0.50% of vanadium, and 0.10% to 0.18% of oxygen, 100 ppm to 180 ppm of carbon and 50 ppm to 120 ppm of silicon. The alloy contains nothing else apart from zirconium and unavoidable impurities and it is completely recrystallized.
Abstract:
A tube for constituting all or part of a cladding or guide tube for a fuel assembly is made from an alloy containing, by weight, 1.4% to 0.6% of tin, 0.5% to 0.8% of iron, 0.35% to 0.50% of vanadium, and 0.10% to 0.18% of oxygen, 100 ppm to 180 ppm of carbon and 50 ppm to 120 ppm of silicon. The alloy contains nothing else apart from zirconium and unavoidable impurities and it is completely recrystallized.
Abstract:
In a zirconium-alloy fuel element cladding, a method for generating regions of coarse and fine intermetallic precipitates across the cladding wall is provided. The method includes steps of specific heat treatments and anneals that coarsen precipitates in the bulk of the cladding. The method also includes at least one step in which an outer region (exterior) of the cladding is heated to the beta or alpha plus beta phase, while an inner region (interior) is maintained at a temperature at which little or no metallurgical change occurs. This method produces a composite cladding in which the outer region comprises fine precipitates and the inner region comprises coarse precipitates.
Abstract:
The invention relates to a fuel element for a pressurized-water reactor comprising a number of fuel rods arranged in a square lattice and wherein certain positions in the lattice contain guide tubes for receiving control rods, wherein the fuel element can be used for higher burnup by manufacturing the guide tubes of the element such that their irradiation-induced growth is reduced and their corrosion resistance is increased compared with conventionally manufactured guide tubes. This is achieved by finally heat-treating the guide tubes in two steps, the first step being a beta quenching and the second step a heat treatment in the alpha-phase region.
Abstract:
A process for hydrothermal oxidation of combustible materials in which, during at least a part of the oxidation, corrosive material is present and makes contact with at least a portion of the apparatus over a contact area on the apparatus. At least a portion of the contact surface area comprises iridium, iridium oxide, an iridium alloy, or a base metal overlaid with an iridium coating. Iridium has been found to be highly resistant to environments encountered in the process of hydrothermal oxidation. Such environments typically contain greater than 50 mole percent water, together with oxygen, carbon dioxide, and a wide range of acids, bases and salts. Pressures are typically about 27.5 to about 1000 bar while temperatures range as high as 800.degree. C.
Abstract:
A Zircaloy cladding having an outer region comprising fine precipitates and inner region comprising coarse precipitates is provided. The outer region comprises about 10% and the inner region comprises about 90% of the cladding wall thickness. Such Zircaloy tubing is resistant to propagation of cracks and at the same time resistant to corrosion in boiling water reactors (BWR). Resistance to damage caused by the pellet-cladding-interaction can be achieved by standard application of a zirconium or zirconium-alloy liner on the tubing inside surface.
Abstract:
In a zirconium-alloy fuel element cladding, a method for generating regions of coarse and fine intermetallic precipitates across the cladding wall is provided. The method includes steps of specific heat treatments and anneals that coarsen precipitates in the bulk of the cladding. The method also includes at least one step in which an outer region (exterior) of the cladding is heated to the beta or alpha plus beta phase, while an inner region (interior) is maintained at a temperature at which little or no metallurgical change occurs. This method produces a composite cladding in which the outer region comprises fine precipitates and the inner region comprises coarse precipitates.
Abstract:
A method for controlling the release of nuclear fission products (including Mo, Tc, Ru, Rh, and Pd) associated with spent nuclear fuel heats the spent nuclear fuel to a predetermined temperature for a predetermined period of time. The predetermined temperature is sufficiently high to diffuse the nuclear fission products within the spent nuclear fuel and sufficiently low to avoid the release of volatile fission products from within the fuel. The predetermined period of time is sufficiently long to cause an optimal degree of phase redistribution of the nuclear fission products within the spent nuclear fuel. The product of the process is spent nuclear fuel characterized by separation of the nuclear fission products into discrete Mo-Tc-Ru-Rh-Pd phases within the spent nuclear fuel. The Mo-Tc-Ru-Rh-Pd phases make the spent nuclear fuel safer for long-term disposal in geologic repositories.
Abstract:
In a method of fabricating a channel box for use in a nuclear reactor, Zr-alloy sheet material is formed into a tubular channel box. The method includes solution heat treatment of the Zr-alloy sheet material including quenching from a temperature at which .beta.-phase is present. After the solution heat treatment, portions of the Zr-alloy sheet are thinned relative to other portions by a non-stressing thinning process, such as chemical etching in a bath. The corrosion resistance imparted by heat treatment is retained, and the heat treatment itself is easily performed on material of uniform thickness.