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Contractor Employees Exposed to Radiation at Hekinan Thermal Power Station No. 2

March 25, 2007
Chubu Electric Power Co., Inc.

At approximately 10:00 PM on March 23, three employees of a Chubu Electric contractor performing a scheduled inspection at Hekinan Thermal Power Station No. 2 were exposed to radiation while performing non-destructive testing* of pipes by using radiation for filming.

Special equipment was used to analyze glass badge dosimeters which the workers were carrying. The readings showed the exposure was as high as 38.6 millisieverts (provisional results), indicating that the workers are not at risk of harm from the radioactivity, since the exposure did not exceed the annual threshold (50 millisieverts).

No changes were observed in the physical well-being of the three workers, and professionals at a nearby medical institute found no irregularities in the workers' health during a March 24 diagnosis.

This incident has not caused any leakage of radioactivity.

Overview

• Place of accident: Hekinan Thermal Power Station Unit 2 boiler facility
• Job being performed at the time: Using radiation to check welded portions of heat transfer pipe inside boiler
• Source of radiation: Iridium 192
• Cause: Ordinarily, the source of radiation would be collected into a container by remote control. While the workers were doing this work, however, the material was not contained because of a radioactivity joint connection defect.

Overview of Hekinan Thermal Power Station

1 Address: 2-8-2, Konan-machi, Hekinan-city, Aichi
2 Output

No. 1:	700,000 kW
No. 2:	700,000 kW
No. 3:	700,000 kW
No. 4:	1 million kW
No. 5:	1 million kW

Total:	4,100,000 kW

*Non-destructive testing: A testing method that seeks to detect defects within a material and small surface imperfections without physically destroying the object of inspection.