Nuclear Power Plants

Nuclear Power Plants

Nuclear Power Plants

Compact deaerator design results in significant cost saving

The flow rate of return condensate in nuclear power plants is very high. The sprayers in a Stork deaerator can easily handle these large flows and in combination with the integral vessel design this offers significant cost reductions. Not only is the deaerator vessel smaller compared to a tray type design but also the total height of the deaerator is considerably lower. Consequently the structure on which the deaerator is placed is also lower in height. After all , the required NPSH of the boiler feed water pump is determined by the water level in the tank and for a Stork deaerator the total building height can be reduced by a significant number of meters.

Steam turbine by-pass (trip) operation is accommodated

Identical to conventional power plants the steam turbine by-pass (trip) will determine the design of the deaerator. When the steam turbine trips, the steam supply from the steam turbine to the deaerator is cut-off. The temperature in the deaerator drops and a large amount of steam is produced from the water contained in the deaerator. Shortly after this happens, the control system of the plant will direct steam from the boiler to the deaerator. 
Due to the large steam space in the vessel there is sufficient volume in the the Stork spray type deaerator available to accommodate this steam volume and to route it to the sprayer section.

Flawless pre-heater by-pass operation possible

Exceptional operating cases such as by-pass conditions of preheaters are easily accommodated in a Stork spray type deaerator. Due to the high range ability of the steam distribution system and the fact that more heat sources can be combined to deliver sufficient heat in these by-pass conditions.

Name: Olkiluoto Nuclear Power Plant

Location: Finland
Fuel type: Nuclear
Output: 2 x 880 MW
Features: First Evolutionary Power Reactor
Deaerator size: Total length 30800 mm x Dia 4000 mm
Year of delivery: 2006
Outlet flow: 1670 kg/s
Operating pressure: 9.25 Bara
Gross volume: 365 m3
Total weight: 137 tons
Performance: 7 ppb
Design code:  EN13445/PED