[en] The report describes the specifications, design principles and the development program to produce irradiated fuel bundle counters for 600 MW CANDU reactors. The safeguards counters will provide the IAEA with a secure and independent means of estimating the number of fuel bundles transferred to the spent fuel bay between inspections. The technical requirements of the bundle couner sound simple. However, location, reliability, security and operating requirements make the counters highly ''intelligent'' instruments. Specifications which are imposed on these unattended safeguards instruments include independence from continuous station services, concealment of operating status, and tamper resistance and indication. Fuel bundles pass sequentially through the field-of-view of four Geiger counters for detection. A microprocessor analyzes the sequence of the Geiger counter signals and determines the number and direction of bundles transferred. The readout for the inspector includes both a bundle tally and a printed log of the times and dates of transfers. (author)