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At the heart of Itaipu: radiator maintenance
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23/03/2009

The closing lids on U07, the red cover at quota 108, are opened early in the morning on the 16. The heart of Itaipu is exposed and ready for the maintenance work.  

 

 

While other teams spread out to the sections of the generator units (like "rappelling" to rescue fish from the suction pipe), the mechanical maintenance crew removes four radiators, the devices responsible for cooling the generator.

 

There are 16 radiators in all surrounding the generator. Every year, four of them are taken apart for inspection; in four years, maintenance on all radiators is complete. Removing each radiator is a slow process that takes place in an area that understandably requires extreme care.

 

That is where the Itaipu power is generated, in the harmonious interaction between rotor and stator. That is why the temperature in the first hours after the machine stops is still impossible to deal with. After “running in the void” for four hours, large fans are set up on the removed lids and cool the environment to allow technicians to work.

 

According to expert technician Ewerton Arbão da Silva, from the Generator Units Mechanical Maintenance Division (SMMU.DT, in Portuguese), in charge of the generator at the U07 downtime, after the radiators are removed they are taken apart into two sections – lids and body. The lids are taken for maintenance and replaced with others that have already been repaired. “We do that to save time”, said Ewerton. According to him, Itaipu has eight sets of spare radiator lids per machine.

 

During maintenance, the radiator lids undergo a full check-up: golden mussels (a sort of two-shell mollusk) are removed by water jets; cleaning is done via steel shot jets, and a new coat of paint is applied. Occasional machining repairs, if required, are performed at the Electro-mechanics Shop. The body of the radiator has its apron repaired via cold soldering, and the tubes where the cooling water flows are cleaned.

 

Red zone

 

Each unit’s 16 radiators are extremely important because they prevent the generator from overheating. Just imagine the rotor turning at top speed and creating a magnetic field with the stator, which is spinning around it.

 

Through the radiators runs the water that cools the air, decreasing the generator’s internal temperature. However the water, albeit filtered, brings foreign matter capable of damaging the radiator over time. Regular maintenance becomes paramount.