Validation of photoneutron signals during CANDU reactor defuelling

摘要

Photoneutrons are important in CANDU reactors, playing a role in the dynamic properties of the reactors, and acting as neutron sources during subcritical operations. During the defuelling of the Darlington Unit 2 CANDU reactor, delayed photoneutrons provided the neutron source, and the variation of neutron-monitoring signals with time and the configuration of the fuelled core provides a useful set of measure-ments for the validation of the phenomena involved in photoneutron production and detection. The ratio between predictions by MCNP and measured detector signals is on average equal to 1.02 +/- 0.06 over the measured core states between 30 and 450 channels defuelled, and indicates that the methods applied provide an accurate representation of the phenomena related to photoneutrons in CANDU reactors. (c) 2021 Elsevier Ltd. All rights reserved.