[en] The construction of nuclear power plants necessitates an unusual concentration of projecting, building and assembly resources. On the example of the Mochovce nuclear power plant the economic consequences are shown of such a concentration, namely, the surplus costs borne by the building part contractor. A number of circumstances leading to the surplus costs are discussed: the wages of workers building non-nuclear objects have to be levelled up to those of workers building nuclear objects; the temporary aid of workers from other firms also leads to surplus costs; living-out maintenance and accommodation costs are higher than usual; premiums have to be paid out in campaigning for labour; extra pay is needed for overtime and night work; a lower fulfilment of labour norms is to be expected due to the extreme concentration of workers on the site; etc., etc. (A.K.)