Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 75
Book Description
Canmet Review 1982-83
Author: CANMET Review 1982-1983
Author: Canada Centre for Mineral and Energy TechnologyPublisher:
ISBN: 9780660116150
Category :
Languages : en
Pages : 66
Book Description
CANMET Review 1982-1983
Author: Canada Centre for Mineral and Energy TechnologyPublisher:
ISBN: 9780660116150
Category :
Languages : en
Pages : 66
Book Description
CANMET Review
Author: Summaries of CANMET Energy Research Contracts, 1982-1983
Author: T. P. LanzerPublisher:
ISBN:
Category : Power resources
Languages : en
Pages : 68
Book Description
Summaries of CANMET Minerals Research Contracts 1979-1983
Author: Publisher:
ISBN:
Category : Mineral industries
Languages : en
Pages : 122
Book Description
Stress corrosion cracking can potentially cause fuel failures at circumferential ridges in the sheath. finite element computer codes elestres and feast are used to calculate two-dimensional, axisymmetric, elastic-plastic sheath stresses at and near the circumferential ridges. the level of stresses is given by the fuel design (such as pellet/sheath diameters, pellet length, pellet density) and by the operating conditions (such as power history). the accuracy, convergence, and cost of the stress calculations, however, are determined by the discretization used in the calculations: the number of nodes in the finite element mesh; the shape of the individual finite elements; the pattern into which the finite elements are arranged; and the size of the calculation-steps into which the power history is subdivided. in this study, we determined the discretization that gives a reasonable compromise of accuracy, convergence, and cost for the stress calculations. the highest accuracy is obtained by using triangular finite elements of aspect ratios close to one, and assembling them into hexagonal patterns. to caputure the stress gradients, five nodes are required across the sheath wall at the ridge, but two nodes are sufficient near the midplane of the pellet. the resulting mesh contains about 200 nodes and about 300 finite elements. calculation-steps of 6 kw/m provide a convergent solution, with a factor of two margin against numerical divergence. with the above arrangement, feast needs about 2.4 seconds on a cdc/cyber 175 computer to calculate sheath stresses per calculation-step. six radial nodes at the ridge would double the computing cost. decreasing the size of the calculation-steps means more calculations are needed to analyze a given power history, giving a linear increase in computing cost.
CANMET Report
Author: Canada Centre for Mineral and Energy TechnologyPublisher:
ISBN:
Category : Metallurgy
Languages : en
Pages : 434
Book Description
Review of the Coprocessing of Coals and Heavy Oils of Petroleum Origin
Author: Canada Centre for Mineral and Energy TechnologyPublisher:
ISBN:
Category : Coal gasification
Languages : en
Pages : 24
Book Description
CANMET Catalogue of Publications
Author: Canada Centre for Mineral and Energy TechnologyPublisher:
ISBN:
Category : Government publications
Languages : en
Pages : 100
Book Description
Canmet review 1982-83
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Zircaloy-4 fuel sheath specimens 15.2 mm diameter by 0.42 mm wall thickness with beryllium-brazed appendages have been laboratory tested at high temperature with internal gas pressurization and inert gas shielding of the outer surfaces. with sufficient hoop stress at temperatures less than 1073 k cracks, which were due to a beryllium assisted crack penetration mechanism, were found to occur at the appendages. formulae to predict the beryllium penetration and rupture have been derived by westinghouse canada ltd. based on data from direct resistance-heated specimens. the formulae are thought to be able to predict the phenomenon in fuel sheaths with changing temperature/pressure histories. a series of tests was done by canadian general electric to determine the formulae ability to predict the occurrence of beryllium assisted crack penetration in specimens heated indirectly with internal heaters. the tests showed: 1) there is an incubation period before any beryllium assisted crack penetration occurs. 2) at sheath temperatures below approximately equal to 1073 k sheath rupture by excessive mechanical strain will preclude rupture by beryllium assisted crack penetration. 3) the formulae predicted rupture times above and below the braze alloy melting temperature within the previously determined confidence limits. 4) predictions of beryllium assisted crack penetration rupture for specimens with changing temperature/pressure histories were of similar accuracy to predictions of isothermal tests. 5) specimens with an appendage plane of one bearing pad and three spacer pads behaved similarly to the specimens with four spacer pads on which the formulae were based.