Cooling tower refurbishment

At the Dětmarovice power plant in the Czech Republic, the concrete shell of cooling tower 3 was repaired in the first half of 2019, for which purpose a range of innovative repair and protection systems from MC were used.
The Dětmarovice coal-fired power plant is located in northern Bohemia near the Polish border. It went into operation in 1975 and today has an installed capacity of 800 MW. It was no coincidence that, in 2019, MC was asked to assist in the repair of cooling tower 3: Because operator ČEZ, a.s. had already opted for MC repair and protection systems in the past – during the first rehabilitation campaign in 1996, to be precise. Offering new and innovative product systems, MC was again the obvious choice for this latest refurb. The planning and execution works were entrusted to REKO PRAHA, a.s., a planning and engineering company that specialises in the construction, repair and maintenance of cooling towers.

 

With the results of tests on SPCC mortars from other manufacturers falling short of the quality requirements specified by REKO, the company consulted MC’s field sales adviser Zdenek Darebnik, and together they developed a new solution based on MC’s Nafufill SM 04 microsilica-modified repair mortar.

 

Success with microsilica-modified repair mortar

The single-component mortar has been optimised for both the partial patching and full-surface repair of horizontal concrete components and can also be applied by dry spraying. Thanks to minimised scatter waste and optimised aggregate composition, it can be perfectly levelled and smoothed. Nafufill SM 04 is classified as non-combustible per building material class A1 according to EN 13501-1, has a high resistance to carbonation and is resistant to external influences such as temperature fluctuations. And although water-impermeable, it is also open to water vapour diffusion.

 

Proven solution for cooling tower coating applications

Nafufill KM 110 fine mortar was then used in the next step to optimise the levelled surface. This in turn was followed by renewal of the protective coatings on the cooling tower surfaces. For the internal areas, the applicator opted for a solution from MC which has already proven its effectiveness in more than 200 cooling tower applications. After priming with MC-DUR 1277 WV, the lower two thirds were coated with a reaction resin coating of MC-DUR VS NR 3, with the upper third being sealed with UV-resistant MC-DUR VS PUR.

Top external protection with MC-Color Flex

The external surfaces were sealed with the innovative MC-Color Flex protection system. The initial layer of MC-Color Primer was coated with MC-Color Flex pure, which is highly resistant to UV, weathering and alkali attack. As a crack-bridging concrete protection coating for exterior surfaces exposed to the elements, this system is colour-fast thanks to its UV-stability and weathering resistance, exhibits integrated greening protection and also offers great benefits due to its low dirt absorption capacity. The repair of cooling tower 3 in Dětmarovice was completed on schedule over a period of just two months between April and May 2019. The client and applicator were highly delighted with the results achieved, sure in the knowledge that the new coating will withstand many years of cooling tower service.