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Failure Analysis of CANDU Fuelling Machines and Supporting Equipment

On-site engineering support and metallurgical analysis services for CANDU Fuelling machine and component failure analysis.

​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