Grant: Collaborative Research and Development Grants
University of Western Ontario
$40,000.00
Intergranular residual stress analysis of irradiated Zr-2.5Nb pressure tube material
FY 2019-20
Summary
Nuclear energy contributes to more than 50% of power production in Ontario. In the core of the CANada Deuterium Uranium (CANDU) reactors, zirconium and its alloys have been used extensively. This is due to having good mechanical properties, and being transparent against the neutrons generated during fission reactions. At micro-level, zirconium alloys comprise of crystals, also known as grains, with specific atomic arrangement that are oriented in specific direction. Two of the main atomic arrangement observed in zirconium alloys are Hexagonal Close-Packed (HCP) and Body-Centred Cubic (BCC). When zirconium crystals are deformed, their response to the applied load depends on the direction of the load. This is called anisotropy. The crystal structure and orientation are the reasons for such observation.In CANDU reactors, pressure tubes are the primary pressure boundary between the heavy water coolant and the cold moderator. These tubes are made of a zirconium-niobium alloy called Zr-2.5Nb. The alloy has about 5% BCC and 95% HCP crystals that are formed during manufacturing process. During service, hydrogen atoms from water coolant can penetrate into the crystals of the pressure tube and form hydrides. These hydrides are brittle and reduce the expected life-span of the tube. One of the parameters that affects the rate of hydride formation is the state of the stress in the tube's crystals. It has been observed that the orientation of the hydrides formed in the two ends of the tube are not consistent. This will significantly affect the fracture toughness of the tubes. It is hypothesized that this is due to microstructural variations and development of different level of residual stresses at the two ends of the tube. In this project, samples will be extracted from the two-ends of neutron irradiated pressure tubes to investigate such variations. Finite element modelling will be used with experiments to understand the level of stress variation along the tube. This project will be in collaboration with the Canadian Nuclear Laboratories. The long term goal of this project is to modify manufacturing routes to increase life-expectancy of the pressure tubes.
Program
Collaborative Research and Development Grants
Recipient
Location
Ontario, Canada
Recipient Type
Academia
Type
Grant
Source
NSERC's Awards Data
As published
Application id
531068-2018
Name nom
Abdolvand, Hamidreza
Department département
Mechanical and Materials Engineering
Organization id
36
Institution établissement
University of Western Ontario
Province en
Ontario
Province fr
Ontario
Country en
CANADA
Country fr
CANADA
Fiscal year exercice financier
2019
Competition year année de concours
2018
Award amount
40000
Program id
CRDPJ
Program name en
Collaborative Research and Development Grants
Program name fr
Subventions de recherche et développement coopérative
Group en
RESEARCH PARTNERSHIPS
Group fr
PARTENARIATS DE RECHERCHE
Committee code
96
Committee name en
RPP Internal Decision Cttee
Committee name fr
Cté de décision interne - PPR
Area of application code
302
Area of application group en
Energy resources
Area of application group fr
Ressources d'énergie
Area of application en
Nuclear energy
Area of application fr
Énergie nucléaire
Research subject code
2001
Research subject group en
Materials science and technology
Research subject group fr
Science et technologie des matériaux
Research subject en
Materials structure, properties and testing
Research subject fr
Structure, propriétés et essais des matériaux
Installment
inst:2 - 2
Partie
2
Nb partie
2
Application title
Intergranular residual stress analysis of irradiated Zr-2.5Nb pressure tube material
Keyword
NSERC
Application summary
Nuclear energy contributes to more than 50% of power production in Ontario. In the core of the CANada Deuterium Uranium (CANDU) reactors, zirconium and its alloys have been used extensively. This is due to having good mechanical properties, and being transparent against the neutrons generated during fission reactions. At micro-level, zirconium alloys comprise of crystals, also known as grains, with specific atomic arrangement that are oriented in specific direction. Two of the main atomic arrangement observed in zirconium alloys are Hexagonal Close-Packed (HCP) and Body-Centred Cubic (BCC). When zirconium crystals are deformed, their response to the applied load depends on the direction of the load. This is called anisotropy. The crystal structure and orientation are the reasons for such observation.In CANDU reactors, pressure tubes are the primary pressure boundary between the heavy water coolant and the cold moderator. These tubes are made of a zirconium-niobium alloy called Zr-2.5Nb. The alloy has about 5% BCC and 95% HCP crystals that are formed during manufacturing process. During service, hydrogen atoms from water coolant can penetrate into the crystals of the pressure tube and form hydrides. These hydrides are brittle and reduce the expected life-span of the tube. One of the parameters that affects the rate of hydride formation is the state of the stress in the tube's crystals. It has been observed that the orientation of the hydrides formed in the two ends of the tube are not consistent. This will significantly affect the fracture toughness of the tubes. It is hypothesized that this is due to microstructural variations and development of different level of residual stresses at the two ends of the tube. In this project, samples will be extracted from the two-ends of neutron irradiated pressure tubes to investigate such variations. Finite element modelling will be used with experiments to understand the level of stress variation along the tube. This project will be in collaboration with the Canadian Nuclear Laboratories. The long term goal of this project is to modify manufacturing routes to increase life-expectancy of the pressure tubes.
