Special Maintenance List
It’s difficult to control the amount of radiation workers are exposed to during the course of their work at nuclear power plants, but we have come up with some ways to reduce the levels of exposure so that they can perform their duties as efficiently and safely as possible.
Reduction of exposure by
performing chemical decontamination on valves.
performing chemical decontamination on valves.
Overview
Remove the radioactive material that has attached to the inner surface of the valve by applying a chemical decontamination agent to the inside of the valve (upper valve body , bonnet + valve disc).(DF value 20) Decontamination of a polluted tool and a disposable part can be performed at the same time by placing a decontamination container on the decontamination loop.
Decontamination Time
Approximately for 3 days
Image of the chemical decontamination
Effect of Decontamination on the Valve Disc
| Location | Before(mSv/h) | After(mSv/h) |
|---|---|---|
| Stellite Part | 45.0 | 0.8 |
| Center | 25.0 | 0.6 |
* An example of our past result
Before Valve Disc VT
After Valve Disc VT
