Nexus of environmental issues and cooling of NPPs. K. Kavvadias V. Anastasov

Transcription

1 Nexus of environmental issues and cooling of NPPs K. Kavvadias V. Anastasov IAEA Training Workshop - September 2017

2 - Context - Cooling systems - Environmental issues - Conclusions

3 Water stress - annual water supplies drop below 1,700 m 3 per person, Water scarcity - annual water supplies drop below 1,000 m 3 per person, Absolute scarcity - below 500 m 3 per person. By 2025, 1.8 billion people will be living in countries or regions with absolute water scarcity, and two-thirds of the world's population could be living under water stressed conditions. With the existing climate change scenario, almost half the world's population will be living in areas of high water stress by Source: FAO

4 Population, energy consumption and water consumption for energy, World Population (million) Energy consumption (EJ) Energy consumption (GJ/capita) Water for energy (billion m 3 /year) Water for energy ( m 3 /capita) Electricity generated from nuclear power (EJ) 2005: 10.4 (15.5%) Water consumption by nuclear power (billion m 3 ) 2005: 7.6 (18.5%) Water withdrawals (Billion m 3 ) Power generated (Billion MWh)

5 Water consumption for primary energy m 3 /GJ Hydro Crude oil Coal Natural gas Uranium mining and processing Source: WWDR4, 2012.

6 Average energy use for water production (in the US). Energy for distribution not included. Source / treatment Energy use (kwh/million L) Surface water 60 Water Wastewater Groundwater 160 Brackish groundwater Seawater Trickling filter 250 Activated sludge 340 Advanced treatment without nitrification 400 Advanced treatment with nitrification 500 Source: WWDR4, 2012.

7 Cooling sources Palo Verde NPP 100% of cooling water from the municipal wastewater system Limerick NPP 40% of cooling water from the coal mine waters. Cooling technologies In the 60s a shift was made towards cooling towers because of the limitations posed by the water quality and availability. Dry cooling still not used due to big penalty on electricity generation

8 Cooling pond Cooling tower Once through - Lake Once through - River Once through - Sea water Number of reactors Source: PRIS

9 - Up to few thousands of meters long, - Pipe profile dimensions 7x7 meters, - Depth of meters, - Embedded in the seafloor, - Typical T = 10 C, - Typical capacity m 3 /s.

10 _ + Ecological damage during construction, Thermal, chemical and physical discharge load to the water body, Entrainment and impingement of living organisms, Withdrawal of large water quantities. Low visual effects, No microclimate changes, Less land use, Efficient.

11 - Natural draft, - Diameter 120m, height 180m, - Surface area 15 ha, - Evaporation cooling, - T same as OTC, - Reduced plant efficiency.

12 _ + Visual impact, Large land use, Possible fogging and icing, Higher water consumption, Noise, Efficiency penalty. Low water withdrawal, limited to make-up water, Variety of water sources, Reduced entrainment and impingement.

13 - Mechanical draft, - Wet/dry cooling mode, - Diameter 160m, height 50m, - Surface area 20 ha, - Enhanced evaporation cooling, - T same as OTC, - Reduced plant efficiency.

14 _ + Higher land use, Higher energy demand to run the system. Further reduction of water withdrawal, Reduction of visual impacts, Reduction of fogging and icing.

15 - Evaporation cooling, typical pond surface 15 km 2, - Enhanced evaporation with sprays, pond surface 1 km 2, - Currently m 2 per MW t, - T same as OTC, - Reduced plant efficiency.

16 _ + Very large land use, Possible microclimate changes, Possible water loss to ground, Efficiency dependant on stochastic environmental conditions. Simple construction, Simpler maintenance, Reduced emissions, Water storage that reduces the need for immediate make-up, May provide new habitat.

17 Water is both, limited and essential for electricity generation. Electricity mainly is used to treat and transport the water for various needs. Environmental mitigation is possible for all the cooling system options, though usually affecting the plant efficiency. Nuclear power can be reliably generated with reasonable water quantities and low environmental impacts.

18 Water and energy must be put in the broader frame of environmental and socio-economic issues. Water use and consumption figures could vary - depending on the life cycle approach used in strategic decision-making. Life cycle assessment should align the water requirements and the climate change implications of the power generating system.

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