A CANDU fuelling machine contains numerous moving/rotating components (ball screws, linear and rotating bearings, mechanical gears, mechanical seals, etc).
Premature wear and/or failure of key fuelling machine components and support equipment can result in the need for unscheduled or excessively frequent overhauls and repairs, with associated negative effects: maintenance costs, radiation exposure, reduced fuelling rates, and upsets to the general head overhaul schedule.
A Team Approach
Kinectrics forensics experts work closely with station investigation teams and equipment suppliers to quickly identify and analyze the cause of fuelling machine failures.
During disassembly inspections, rapid response, on-site engineering support assists with preliminary failure mode identification and the selection of sub-components for detailed forensic examinations.
Active samples are shipped to Kinectrics’ Radioactive Materials Laboratory for detailed metallurgical analysis, failure component analysis and confirmation of the apparent cause. The failure analysis results and recommendations are reviewed by station staff to ensure that the immediate and longer term corrective actions are appropriate to mitigate similar failures in other units.
Recent Projects
Examples of recent CANDU fuelling machine investigations include:
stress corrosion cracking of a ram ball screw
fuel carrier/endfitting liner galling issues
overload failure of a ram spline
abnormal charge tube ball nut wear
failure of a ram extension tube weld
ram tape drive failure
endurance testing of hard chromium coatings
fatigue failure of bell gear shoulder bolts
condition assessment of reactor area bridge ball screw
corrosion failure of a nitrided guide sleeve latch key
power track trolley chain link failures
reactor area bridge bearing failure
investigation of catenary hose leaks
flow injection metal bellows hose failure analysis of wear debris from FM filters