Company ROEZ, s.r.o. within the contract „IPR EMO 18028 - Modifikácia dýz merania prietoku NV za VTO“, as a one of two main contractors within modernization and total power output increasing of nuclear power plant, successfully realized for Slovenské elektrárne, a.s. project of design, fabrication, testing, installation and commissioning of measuring nozzles of feed water flow and completion of measuring devices of the secondary circuit of common island on both units of NPP EMO1,2.

The subject of the work was the design, manufacture, supply and installation of 4 pieces of new nozzles DN450 designed and manufactured according to ASME PTC 6-2004 and 20 pieces of new cone meters DN150-DN400 designed and manufactured according to ISO 5167-5.


Measuring nozzles are installed as an important element for guarantee measurement of turbine efficiency, resp. as a replacement for previously installed measuring orifices on the following routes:

  • feed water pipeline out of VTO2,
  • main condensate pipeline from NTO5 to NN,
  • pipeline from the collector to the main condensate pipeline before NN,
  • steam condensate pipeline from VTO1 to NN,
  • steam condensate pipeline from SPP to NN,
  • steam condensate pipeline from NTO5.


Measuring nozzles according to ASME PTC 6-2004

Measuring nozzles DN450 are included in safety class BT3 according to ÚJD Decree no. 430/2011 and in seismic category 2b. The nozzles are made of P265GH with internal armor made of 1.4404. After wet calibration of measuring nozzles, they have a maximal measurement uncertainty 0,35%.

Due to the layout of existing technology in turbine hall in NPP EMO1,2 we had to solve the problematic issue of transport. It was necessary to design a sophisticated technical solution for splitting the nozzles into 3 parts already in the production phase, what allows multiple connection and disconnection of the nozzles, without affecting the calibration results.


Cone meters according to ISO 5167-5

Existing orifices had to be replaced with calibrated cone meters with an inspection hole due to unsatisfactory straight pipeline lengths. Cone meters have the same classification as the original measuring orifices, ie. are included in safety class BTN and in seismic category 2b. The cone meter body is made of P265GH, while the cone is made of 1.4541. The cone meters were calibrated by wet calibration.


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