Brazilian nuclear fuel company Industriás Nucleares do Brasil (INB) has completed the underwater repair of a damaged fuel rod canister in the storage pool at unit 2 of the of Angra NPP at the Itaorna Beach in Angra dos Reis, Rio de Janeiro. Damaged fuel rods from a light water reactor such as Angra 2 can release radioactive elements such as iodine-131 into the coolant water. Usually damaged elements removed from the reactor are placed in a sealed canister and stored alongside other used fuel elements in the used fuel pool. In April 2014 when a damaged rod was removed to a canister, the canister was damaged while being manoeuvred. Instead of buying a new container, plant owner Eletronuclear and INB chose to repair it some 12 metres underwater with the damaged fuel elements still inside and undamaged used fuel stored elsewhere in the pool.
The repair required two years of planning and preparation using technical drawings of the canister, and making use of Eletronuclear's capabilities and INB's machining skills. After a test run at an INB facility, the team performed the repair "with a high level of technical sophistication and pinpoint accuracy," said Rogger Faria, the mechanical engineer at INB who led the project. Based on the experience gained, a partnership for a commercial service has been established, offering ultrasound inspection of fuel elements in NPP used fuel pools and INB is now pursuing qualifications in fuel element repair.