Use of a refueling machine mast sipping system to detect leaking FAs during operational fuel cladding failure detection

Abstract

The paper considers the processes involved in leaking fuel elements during the shutdown and preparation of a reactor for refueling in the case of a defect located at the bottom, in the middle, or at the top of the fuel column. The volume and activity of gaseous fission products released during fuel cladding failure detection were evaluated using the mast sipping system of the refueling machine. It is demonstrated that the sensitivity of the beta-radiometer, which starts at 37 kBq/m³, provides for the detection of leaking fuel elements at any power density located at various locations of the defect along its height. Neglecting to wash all fuel elements in the FA with bubble air may result in a failure to detect leaking fuel elements.