Prosecutors on Tuesday raided the office of the state-run nuclear power plant operator’s senior executive in Seoul, as part of its investigation into the company’s corruption scandal.

Investigators have been widening their probe into Korea Hydro and Nuclear Power Corp. since last year for turning a blind eye to the falsification of test certificates for parts and materials used in nuclear reactors.

The Busan District Prosecutors’ Office confiscated hard drives and documents from KHNP executive vice president Lee Chung-goo’s office to look for evidence that he took bribes from parts suppliers.

“We have yet to find out about the raid this morning,” said Kim Tae-seok, a public relations official at the company.

According to the KHNP officials, Lee was promoted in January from operating the Wolseong Nuclear Power Plant in Gyeongju, North Gyeongsang Province.

So far, more than 100 officials from the operator, parts suppliers and certifiers have been indicted on charges of forgery and corruption since the scandal broke in May. Prosecutors are also believed to be investigating several minister-level government officials over their involvement.

The discovery came to light when several nuclear reactors were unexpectedly shut down. The stoppages were later found to be due to substandard parts from JS Cable and fake quality certificates.

By Suk Gee-hyun (monicasuk@heraldcorp.com)