Temporal evolution of activation products in a zircaloy –4 guide tube and the estimation of its external gamma dose rate for decommissioning activities

The dismantling of structural objects during the decommissioning of nuclear facilities needs
radioactive source characterisation for the planning of decommissioning strategies in compliance
with the ALARA (as low as reasonably achievable) principle. The sources may arise from neutron
activation of the structural components in the reactor core as well as contamination due to the
radioactive release from the fuel occurred during normal operation or unplanned events in a nuclear
power plant (NPP). In a pressurised heavy water reactor (PHWR), various in-core components are
predominantly made of either zircaloy –2 or 4. The nuclides present as impurities in the zircaloy,
playing a crucial role in the activity inventory due to neutron activation of those nuclides, which
in turn determine the external gamma dose rate. The activity of the activation products depend on
the neutron flux seen by the component, duration of irradiation and cooling period, half-lives of
the daughter products a...

Source: Journal of Radiological Protection - January 14, 2020 Category: Physics Authors: Riya Dey, Tanmay Sarkar, Chitra Subramanian, Srinivasan Anand, Kapil Deo Singh and Mukund Shrinivas Kulkarni Source Type: research