• Evaluation of irradiation-induced creep rate: application to the vacancy dislocation loop contribution

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      https://www.ias.ac.in/article/fulltext/pram/012/03/0275-0289

    • Keywords

       

      Stress; creep; irradiation; vacancy dislocation loops; rate theory; distribution functions

    • Abstract

       

      Irradiation (as in a nuclear reactor) drastically affects the defect structure and its time evolution in a material, and induces new creep mechanisms in it. We present a formalism to evaluate the contribution to creep owing to such mechanisms. Beginning with the phenomenological constitutive relation for the strain appropriate to a given mechanism, we put in simple statistical considerations to derive an expression for the corresponding creep rate. This formal expression is in terms of the defect production rate and a non-equilibrium probability distribution function involving the pertinent properties of the defect type concerned. A convenient approximation scheme for practical calculations is employed, that also makes contact with standard rate theory and provides a proper interpretation for the variables occurring there. As an illustration, we evaluate the contribution to irradiation-induced creep from the orientation-dependent shrinkage of vacancy dislocation loops in an applied stress field. The circumstances inducing transient and non-transient creep are clarified and a numerical estimate is given for the latter component.

    • Author Affiliations

       

      K Krishan1 V Balakrishnan1 S K Ray1

      1. Reactor Research Centre, Kalpakkam - 603 102
    • Dates

       
  • Pramana – Journal of Physics | News

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