Prosecutors in South Korea raided the Ministry of Trade, Industry and Energy, Korea Gas Corporation(KOGAS) and Korea Hydro and Nuclear Power Company(KHNP) as part of an investigation into suspicions of data manipulation in an economic feasibility study of the Wolsong No. 1 nuclear reactor.

On Thursday, the Daejeon District Prosecutors' Office sent prosecutors and investigators to obtain files and computer hard disks related to the allegations.

The Board of Audit and Inspection(BAI) earlier found that the ministry and the public corporations intentionally undervalued unit sales and labor costs in the feasibility evaluation before a decision was made on the reactor's early closure in June 2018.

The closure of the Wolsong No. 1 reactor has remained controversial since President Moon Jae-in decided in 2017 to decommission the reactor earlier than scheduled in line with his green energy policy.

The main opposition People Power Party(PPP) filed complaints against former Energy Minister Paik Un-gyu, KOGAS CEO Chae Hee-bong, KHNP CEO Chung Jae-hoon and nine others, accusing them of manipulating data to influence the early shutdown decision.