The pressure tubes in the CANDU power reactors

Abstract Nuclear power reactors using zirconium alloy pressure tubes generate electricity in several countries. Such reactors are particularly important in Ontario, where CANDUs generate about 30% of the total electricity produced in the Province. Starting with the commitment of NPD-2 in 1956, the pressure tubes of the first five CANDU reactors were made of cold-worked Zircaloy-2, an alloy of Zr and Sn. This alloy was developed by the US Navy, but the decision to use it in a cold-worked condition was based on AECL work. In 1958, the USSR published information on a new alloy, Zr-2.5 wt% Nb. The Nb promotes stabilization of the β-phase in the material, thus presenting opportunities of exploiting metallurgically strong pressure tubes analogous to the heat-treatable α-β titanium alloys. After construction of two reactors using Zr-2.5 wt% Nb in a quenched and aged condition, an extensive development program on cold-worked Zr-2.5 wt% Nb pressure tubes resulted in them becoming the reference tubes for all CANDU reactors committed since 1966. Anticipating the future needs of the domestic and export markets, AECL have pressure tubes of Zr-3.3 wt% Sn-0.8 wt% Nb-0.8 wt% Mo (Excel) in an advanced state of development. These tubes will be used in an annealed condition; our projections show that they will have improved dimensional stability over the lifetime of the reactors. These improvements result from experimental programs leading to an understanding of the relationship between microstructures and fabrication variables and effects of the environment during service in nuclear reactors.
Keywords: Technology, Metallurgical sciences, Pressure tubes, Reactors, CANDU reactor, Alloys, Zircaloy, Niobium.
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Summary: This paper discusses the changing nature of reserve/consumption ratios, using data from Canadian operations and focus-sing particularly on copper.
Publication: CIM Bulletin
Author(s): F.-W. WELLMER
Keywords: Mineral economics, Reserves, Consumption, Copper deposits, Production, Lead, Zinc.
Issue: 831
Volume: 74
Year: 1981
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Summary: The recent development of the continuous casting process for steel has required basic understanding in a number of areas in the metallurgcal sciences. In some areas, information is still lacking. The success of the application of basic knowledge and research to the process is evidenced by the fact that a large percentage of the steel now produced in the world is produced by continuous casting.A number of areas in which metallurgical science has contributed and is currently contributing to...
Publication: CIM Bulletin
Author(s): F. WEINBERG
Keywords: Technology, Metallurgical sciences, Casting, Continuous casting, Steel, Heat transfer, Fluid flow, Solidification, Strength, Ductility.
Issue: 831
Volume: 74
Year: 1981
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Summary: In describing the alteration of porphyry systems, the term "secondary K-feldspar" appears to be an oversimplification. A better term would be "alkali feldspar" alteration, because in actual fact the replacement feldspars show gradational changes from an albite, which is important in some systems, to an alkali feldspar containing minor orthoclase molecule, to true orthoclase.There are several textural varieties of secondary alkali feldspar present in the porphyry systems...
Publication: CIM Bulletin
Author(s): CRAIG H. B. LEITCH
Keywords: Mineralogy, Feldspars, Alkali feldspars, Porphyry systems, Alteration, Mineralization, Exploration, Albite, Orthoclase.
Issue: 831
Volume: 74
Year: 1981
Text
Summary: The need to make repairs is seldom a major consideration in the design, fabrication and installation of major components of electrical generation plants. Repair welding, however, is a fact of life in the electrical generation industry, for restoration of degradation in service, from cavitation of hydraulic turbine runners, to corrosion and fatigue damage in pressure vessels. In making weld repairs to carbon and low-alloy steels, the largest source of trouble is hydrogen embrittlement and...
Publication: CIM Bulletin
Author(s): W.H.S. LAWSON, D. MILLS
Keywords: Technology, Metallurgical sciences, Welding, Repair welding, Power plants, Hardness
Issue: 831
Volume: 74
Year: 1981
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Summary: Cryogenic engineering is concerned with components and machines which operate for long periods of time at temperatures within a few degrees of absolute zero. The absence of a ductile-brittle transition is thus the prime component of the specification for a suitable low-temperature alloy. The word "cryo" means "frost-forming", and this leads to the second component of the alloy specification, which is resistance to corrosion in humid atmospheres. Further, although most...
Publication: CIM Bulletin
Author(s): H.W. KING
Keywords: Technology, Metallurgical sciences, Stainless steels, Cryogenics, Phase equilibrium, Ferromagnetic transitions, Alloys, Magnetization, Steel.
Issue: 831
Volume: 74
Year: 1981
Text
Summary: Plastic yielding and flow in metals is dependent on the microscopic process of simple shear along crystallographic planes and directions known as slip. Thus, by altering the crystallographic direction of the stress axis or placing constraints in the direction of plastic flow, anisotropy of yield strength for the same material is observed. This phenomenon is called texture strengthening. The application of this concept to highly anisotropic crystal structures such as the hexagonal group of...
Publication: CIM Bulletin
Author(s): S. SAIMOTO, L COLLINS, G.B. HOBBS
Keywords: Technology, Metallurgical sciences, Strengthening, Texture strengthening, Heat exchangers, Shear, Stress, Plastic flow, Yield strength, Alloys, Titanium alloys, Zirconium alloys, Copper sheet, Cupro-nickel sheet, Aluminum wire, Steel.
Issue: 831
Volume: 74
Year: 1981
Text
Summary: Most unconformity-type uranium deposits in Saskatchewan occur within a few tens of metres above and/or below the basal unconformity of the 1.45-b.y. Athabasca Sandstone. Graphitic basement rocks coincident with post-Athabasca faulting or brecciation at or near the unconformity are important in localizing uranium deposits which form as tabular, ribbon-like bodies with grades averaging over 2 per cent uranium and containing up to 50,000 tonnes U3O8. Some of these deposits have similar contents...
Publication: CIM Bulletin
Author(s): L.A. CLARK, G.H.R. BURRILL
Keywords: Ore genesis, Uranium ore, Saskatchewan, Australia, Exploration, Jabiluka deposits, Ranger deposits, Rabbit Lake deposit, Midwest deposit, Key Lake deposit, Alligator Rivers deposits.
Issue: 831
Volume: 74
Year: 1981
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Summary: A semi-continuous belt of Aphebian magnesian extrusive and related subvolcank rocks has been delineated by the authors over a distance of 150 kilometres in the central La Ronge lithostructural domain in Saskatchewan. They range in composition from peridotite to basalt and attain true thicknesses of up to 800 metres. For the most part, they are confined to a basal position in the La Ronge/Wasekwan metavolcanic sequence, and appear to have been extruded onto sialic crust. However, at Lynn Lake,...
Publication: CIM Bulletin
Author(s): J.S. FOX, W.G.Q. JOHNSTON
Keywords: Volcanics, Magnesian volcanics, Waddy Lake, Reindeer Lake, Agassiz Mine, Exploration, Nickel exploration, Gold exploration, La Ronge area, Saskatchewan, Manitoba.
Issue: 831
Volume: 74
Year: 1981
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