We have developed a new type of the LKP-M/4 drive mechanism

Linear stepper drives for VVER reactors are one of the strategically important products of our company. Therefore, we are constantly striving to improve them and to develop new types. The latest LKP-M 4 model successfully passed the extended durability test in summer and designer Igor Martinec, who was in charge of its development, told us how innovative this type is.

LKP-M/4 control rod drive tests

“Compared to the previous types, this model differs mainly in the innovative design of the flange joint between the drive housing and the top of the position indicator, which is on the border of the primary circuit. The joint replaces the original two flange joints, making it much easier for the operating staff and lighter in terms of seismic properties.

Another significant innovation is the adjustment of the UP-4 position indicator stepper sensor, thanks to which the position of the control rod can be determined even in the case of a simple failure of conductor in the sensor winding. Practically it means that the LKP-M/4 drive can be operated despite of failure of any of the coils until the reactor is shut down properly, without completely losing information about the position of the control rod. The development of the new stepper sensor winding was also connected with development of a new suspension rod with a modified shunt, necessary for determining the position of the control rod. The development of the stepper sensor was also aimed at reducing the number of connection outlets from 18 to 12, so that the new UP-4 stepper sensor could be used without increasing the supply routes to the NPP beyond the project.

Thanks to these modifications, the new LKP-M 4 is more versatile than the previous model, and can be newly used also at VVER 1200 reactors.”

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