DKM, division of Clextral SAS, provides extra-borating pumps for the new third generation EPR nuclear reactors. The technology equips in particular new generation nuclear power plants located on the Olkiluoto site in Finland (EBS pumps) and the site of TAISHAN China (RBS pumps).
The extra-borating pump is a triplex pump with a mechanical drive, and with three parallel pumping heads. These pumping heads have three plungers, placed at an angle of 120 degrees from one another. Power is supplied to them by a constant high speed motor and a gear box.
Specifications:
- Fixed flow rate: up to 12 m3/hour
- Pressure: up to 260 bar (3770 psi)
- Maximum Stroke: 130 mm
- Maximum thrust: 130 kN
- Maximum power of motor: 160 kW
Mechanical drive:
The movement of the plunger piston is achieved by an eccentric rod system. Ball bearings guide the part’s rotating movement. The mechanical assembly is housed in an oil casing for lubrication.
The three pumping modules are interconnected by a splined shaft with an angular offset of 120 °. The use of 3 pumping heads reduces the flow variation at the pump outlet (<3%).
The gearbox reduces the speed of the moving parts to approx. 100 cycles per minute and thus minimizes the risk associated with moving part lubrication. As a result no auxiliary lubrication pump is required, eliminating the additional risk of failure; and there is no need for cooling other than that provided by heat exchange with the pump’s environment.
Another advantage of this low operating speed at the pumping level is that our valves are free, and are not equipped with a spring return system (reduced NPSHr or Net Positive Suction Head Required). Gravity force is sufficient to ensure proper positioning, tight on the seat.
The power transmission between the various elements constituting the pump (motor, gear and shaft) is provided by elastic couplings.
Pumping part:
Lining
Sealing is provided by two sets of self-lubricated chevron braids: a high pressure stage and a low pressure stage with guide rings.
Nomex / PTFE and Carbon/ PTFE have replaced the asbestos used as lining on the first generation of RIS011PO pumps.
Check valves
We have acquired most of our experience in the field of nuclear programs for French and overseas contracts, so we use the same design of balls, without springs. The absence of springs enables to decrease the required NPSH.
Accumulators
A pulsation damper is mounted to the pump discharge to reduce the residual pulses of the triplex pump.
Qualification
All system pumps are designed and manufactured in accordance with ASME and RCCM nuclear manufacturing codes.
The principle of the qualification of our pumps is based on the calculation and / or testing to prove the good performance of our equipment in normal and seismic operating conditions.
| DC 100 DKM PUMP | DC 130 DKM PUMP |
|
|
