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Following the instruction to compile
an investigative report in response to pipe thinning phenomena, issued
by the Nuclear and Industrial Safety Agency on August 11, 2004, the Kansai
Electric Power Co., Inc. (Kansai Electric) is now reviewing its inspection
records.
The findings of our investigation to date are shown below.
The investigation has so far revealed
that there was one section at the steam converter heating steam systems
of each of Mihama Unit 3, Takahama Unit 1, and Ohi Units 3 & 4 (four sections
in total) where wall thinning has not been monitored and evaluated.
At present, the only steam converter
in operation is the one at Takahama Unit 1. Kansai Electric will stop
operating the steam converter and isolate it to ensure safety.
The other three converters are not in
operation now.
| Plant |
System |
Position |
Quantity |
Action |
| Mihama 3 |
Steam converter
heating steam line |
Downstream of orifice |
1 |
(Plant shut down) |
| Takahama-1 |
Steam converter
heating steam line |
Downstream of orifice |
1 |
Equipment shut down
and isolated |
| Ohi-3 |
Steam converter heating steam line |
Downstream of control valve |
1 |
(Plant shut down) |
| Ohi-4 |
Steam converter heating steam line |
Downstream of control valve |
1 |
(Plant shut down) |
* The steam converter is part of the
plant auxiliary system, which supplies steam to the air conditioner, helps
heating tank water, etc., provides turbine gland steam during plant startup,
and supplies steam to the seawater desalination unit. This system is not
safetyrelated and so is not subject to operational restrictions imposed
by the safety regulations. Therefore, plant operation would not be compromised
at all even by shutting down the system.
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