Increased sensitivity of fuel cladding failure detection

The present paper considers the processes occurring in a failed fuel element during fuel cladding failure detection in the mast sipping system of the refueling machine. The time taken for water and fission gas products to leak from a failed fuel element during its lifting was estimated depending on the size of the defect. A period of 10–12 min exposure prior to bubbling was demonstrated to be applicable for detecting defects with a size of about 30 μm. The sizes of gas bubbles leaving the fuel element during the failure detection were estimated along with their rate of ascent. An algorithm for conducting fuel element failure detection that increases the sensitivity of the method without extending the refueling is proposed.