Work on the 4 788 MW Medupi power station by the LP Services consortium is progressing well. A hydro test of parts of the firewater system and the raw water line is scheduled for April and May 2012. Installation of the south plant compressed air equipment began at the end of March,” says consortium partner Lesedi Nuclear Services non- nuclear projects manager Ian Boggon.
The consortium is comprised of Lesedi Nuclear Services, French nuclear firm Areva’s South African engineering, pro- curement and construction subsidiary, fabrication and construction company Wetback Contracts and cooling systems provider Industrial Water Cooling. It achieved one-million working hours and two years of zero lost-time injuries (LTIs) in February owing to strict safety measures and practices.
The installation of the 18 low-pressure systems has progressed well, with little time lost. These low-pressurised systems include the supply and distribution of auxiliary cooling water, raw water, potable water, demineralised water, firewater, compressed air and conditioned water for various ash and coal requirements, as well as fuel oil and lubrication oil, says Boggon.
“The south compressor house is not yet ready for occupation,” says Lesedi site and project manager Armin Müller.
“We only expect to have access to install the air compressors and air dryers by the end of March. However, we have put contingency plans in place to provide the station with compressed air using alter- native solutions.”
Further, various sections of the fire- water distribution system are receiving high priority. This is required to enable the commissioning of the electrical installations and to bring coal and fuel oil onto the site.
The provision of water from the nearby Mokolo pipeline is also making good progress. This will be the primary source of water for the power station once it goes into production, adds Boggon.
“All rainwater and used process water are collected, stored and treated. The clean and dirty drains dams are used for the storage of this water and their construction is also nearing completion. The pipelines used to transport the water are also nearing completion,” explains Lesedi project manager for civil works Francois Visser.
Further, Müller emphasises that the water from the main terrace and from the coal stockyard flows into a pollution control dam, from where it is treated and reused. This also prevents it from entering the natural water system.
Meanwhile, Visser notes that the raw water line construction was hampered because the company encountered about five times more underground rock than it had expected. The granite rock was also exceedingly hard.
“It is difficult to predict underground conditions. We used rock hammers and mechanical peckers where possible and conventional drill and blast methods in areas of solid rock. One example of this is the culvert under the existing Matimba ash conveyor lines. To date, 120 m of horizontal blasting and 12 m of vertical blasting have been completed.
“The raw water pipe is laid between 1.5 m and 1.8 m underground over a distance of 3.6 km and above ground for 5 km. The line takes water from the Mokolo tie-in to a buffering dam and then from the buffering dam into the power station,” says Visser.
“Further, all the topsoil removed is collected and stored to be used for rehabilitation because parts of the line go through sensitive areas. Logistics are a challenge,” he adds.
The consortium celebrated its achievement of two years and one-million work hours without injury or incident in February.
“This safety achievement is [the result] of the way our teams work. We have to be passionate and behave in the right way to ensure that everyone goes home safely every day,” says LP Services (LPS) consortium project lead Horst Lakemeier. He gave significant credit to all the LPS consortium’s subcontractors working on site who played an integral role in the achievement.
The consortium’s site workers agreed to work at achieving another million LTI-free working hours over the next phase of the construction after being challenged by management at the milestone’s celebrations.
Lesedi Nuclear Services MD Francis Carruthers says the zero LTI achievement is remarkable because of the nature of the work carried out on site, including dangerous work at height.
“Please continue doing what you are doing and achieve the goal of two-million LTI-free work hours. We still have a lot of work to do,” he concluded.