Natural draft cooling tower is preferred JEK2 option

The results of the feasibility study were released as part of the latest reports made public before the country prepares for a planned referendum on new nuclear.

Bruno Glaser, Technical Director of GEN energija, said that the precise height of the cooling tower would depend on the type of reactor selected. The four options considered in the study, by engineering firm John Cockerill Hamon, were a natural draft tower, two designs with combined natural and mechanical draft, and mechanical cooling cells with induced draft.

The key advantages for the natural draft cooling tower were said to be "reliable operation, very low electricity consumption and reduced maintenance requirements … it does not require fans to create the airflow, which makes its electricity consumption the lowest among the technologies considered, and it is also characterised by less demanding maintenance. A suitable alternative was identified as a solution with combined natural and mechanical draft, which would require two towers of approximately 75 to 80 metres in height, but would have higher operating costs".

The project company said that the impacts of climate change were taken into account and the final choice "will be subject to further technical verification and spatial placement procedures. It will be necessary to weigh all aspects and choose the most optimal solution that will also be socially acceptable".

A separate preliminary transport study was released to "verify the feasibility of transporting key components to the JEK2 location and to compare possible transport routes from the perspective of technical, logistical and infrastructure requirements".

Eight potential routes were studied from sea and river ports to Krško, with the most suitable one for further consideration judged to be the 274-kilometre road route from Koper via Ljubljana and Celje to Krško. This route would require modifications at 112 places, for additional height or width clearance or the provision of bridging facilities.

"The preliminary study thus represents the starting point for the preparation of the final transport study, which will address more detailed technical planning of the route, determination of potential infrastructure adjustments and further preparation of transport implementation in the next phases of the project. Given the timeline of the planned project, the final transport study could be completed by the end of 2028," the company reports.

The current plan is for a Final Investment Decision to be taken on the project in 2028 or 2029. The estimated overnight construction costs, in 2024 prices, of the project are EUR9.8 billion (USD11.2 billion) for a 1,000 MWe unit and EUR15.4 billion for a 1,650 MW unit.

With financing costs added, JEK2 says, "in the case of a real weighted average cost of capital (WACC) of 2% (at 2% inflation, ie 4% nominal), we estimate the average price of electricity from the power plant to recover the investment at EUR65/MWh, and at a WACC of 4%, the real price is EUR103/MWh".

The project company says: "JEK2 is an investment of exceptional strategic importance, as it enables the decarbonisation of Slovenia's electricity supply and also the self-sufficiency of Slovenia's electricity supply. The nuclear power plant will ensure a stable and reliable electricity supply for at least 60 years (80 or more years if extended). The investment will have an exceptional impact on the Slovenian economy."

Background

Slovenia's JEK2 project is for a new one or two-unit nuclear power plant, with up to 2,400 MW capacity, next to the existing Krško NPP which has a 696 MWe pressurised water reactor generating about one-third of the country's electricity. Krško is owned and operated by Nuklearna Elektrarna Krško, which is jointly owned by Croatia's Hrvatska elektroprivreda (HEP Group) and Slovenia's GEN Energija. The indicative timeline is a Final Investment Decision by 2029, with construction beginning in 2033 and commercial operation in 2041.

Prime Minister Robert Golob has said there will be a referendum before the new nuclear project gets to the construction phase - there had been one due to be held in November 2024, but that was called off amid a political row over how it was being conducted. Last year the two technology contenders - Westinghouse’s AP1000 and EDF’s EPR and EPR1200 reactors - were all judged to be suitable for the JEK2 site by the project company.