Welding phase successfully finishedComplex welding activities |
 The welder at work  The reducer after the removal of the corroded parts. |
Welding phase successfully finishedWednesday June 30 the welding activities on the High Flux Reactor’s reducers were successfully finished. All four corroded locations in the aluminium pipe lines were replaced and the functionality of the cooling water pipes of the High Flux Reactor has been restored. Lloyds assessed the X-ray and ultrasonic inspections. Repair work at the north reducer was very complex. After completion of the first welds, small, superficial imperfections were detected. This caused extra work but with positive results: fully qualified, repaired reducers. There have been no safety incidents during the last repair period and the radiation dose levels for internal and external employees have remained well below the planned limits. Now that the cooling water pipes of the reactor are succesfully repaired, the project will proceed into the phase of the concrete repairs. The following weeks the reactorfloor will be reconstructed by pumping liquid, self-compacting concrete from the bottom upwards into specially prepared formwork. This process will be closely watched with the help of a remote controlled camera. The planned date of the restart remains fixed for the second half of August. Update
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 The PE taped North reducer.  The South reducer with the connection for the dry air pipe. |
Complex welding activitiesThe completion of the welding operation is an important milestone in the High Flux Reactor repair project. The assemblence of the new aluminium parts in the cooling pipe required extensive knowledge and perseverance from all the team members. Mechanical Engineering Sub Project Manager, Mr. John Verbruggen on the welding activities: “The repair of the South reducer went without any problems. However, the North reducer caused more trouble. The welder’s working space was more narrow. After the replacing of the eroded parts, superficial small imperfections were identified in a weld on just one location during an inspection. This was not the case for the South reducer.” The imperfections were formed by a combination of the decreased quality of the reducer’s material and the difficult welding circumstances. The material stress during the welding activities were the direct cause of the imperfections that were hardly visible to the naked eye. “We have solved the problem by sawing out a small part of the new, already repaired, aluminium. This small opening enabled us to sanding the welds from the inside of the reducer”, explains Mr. Verbruggen. “This way, the imperfections in the weld were polished away. After that, the small hole was easily welded shut due to the new aluminium.” All the welds were inspected with the help of X-ray, ultrasonic and penetrating tests. The authorities have subsequently approved the welds. With that the repair project has moved to the next phase with the concrete repair. A content Mr. Verbruggen: “It was an intense period. We are relieved that everything went well. The quality of the reducers has been guaranteed.” |