The National Verification Department for Construction Works asked the Electricity Group of Vietnam (EVN) to invite competent foreign contractors to deal with the leakage problem at Song Tranh 2 hydropower plant.
Vietnamese contractors do not have experience in fixing underwater leakage problems.
The department agreed with the results of EVN's report that the main leakage points were located at 10 expansion joints. These joints were designed to allow concrete to expand in hot temperatures.
EVN made a statement in March in which they said that water flowed downstream with the discharge of 30 litres per second. The Management Board of Hydro power projects 3 tried to resolve the issue, and reduced discharge to 6-7 litres per second on March 27.
According to the department, the first priority is to repair these 10 expansion joints using SR adhesive and polyurethane glue and then repair the water holes, which were designed to receive water absorbed by the concrete walls and divert it into reservoirs before the dam itself began to leak. However, presently some of these holes have been blocked, causing leakage from the joints.
“Vietnamese contractors do not have the experience necessary to deal with this problem," they said. As a result EVN will be required to assess the situation and draw up plans to finish the work before the flood season begins.
The department will be responsible for evaluation of the current situation and for choosing foreign contractors with experience in such work. Their assessment report will be sent to the Prime Minister for approval.
