Control rod drive mechanisms
Modernized LKP-M linear stepping drive
The modernized LKP-M linear stepping drive is the main part of the control and safety system of the VVER 1000 reactor. Each drive can be either independent of the other drives, or work in tandem with them, depending on the commands from the SGIU-M control and safety system of the reactor, which can be supplied with the said drives. The device has been continuously modernized from the very beginning. The most modern, generation III, drives have a lifespan of nearly 40 years.
From 1990 until now, ŠKODA JS has manufactured more than 900 drives for the VVER 1000 units in the Czech Republic, Bulgaria, and Ukraine. As part of the contract, there was also the requirement to supply nine sets of modernized SGIU-M electronics.
Modernized PRO-M control rod drive
The modernized PRO-M control rod drive is the active part of the control system for the VVER 440 reactor. This type of drive, including the electronic control system and position indicator, was developed to improve the operational characteristics, and reduce the probability of failure. Owing to this improvement, the lifespan of the mechanical parts was gradually extended up to the current 25 years. The original drive version had a lifespan of 10 to 11 years.
The drive, with the position indicator, performs the following functions:
- Moving the VVER-440/V 213 type control rod
- Stops the control rod in extreme positions and in between them.
- Indicates the control rod position gradually and independently every 10 mm and 250 mm, and the extreme positions.
- Drops the control rod in the emergency protection mode.
- Prevents the spontaneous movements of the control rod in case of looseness in the upper part of drive.
Up to now, more than 900 PRO-type (of various design) of control rod drives have been manufactured and supplied to the VVER 440 blocks in five countries. In 2005-2007, a modernized version of this drive (type PRO-M) was supplied to Hungarian Paks NPP (76 pcs.). Based on the up-to-date contracts, more than 200 drives of this type will be supplied at Paks NPP and Mochovce NPP 3&4 till 2012.
AZ/BSM control rod drive
In 2006, 54 pieces of control rod drives were produced for the only operating RBMK-1500-type nuclear power unit of Ignalina NPP in Lithuania.
Photogallery on the topic
PRO-type control rod drive mechanism – detail
PRO-type control rod drive mechanism – detail
PRO-type control rod drive mechanism – testing stand
Linear stepper drive – LKP – blocks of electromagnets
Linear stepper drive – LKP – blocks of electromagnets
Linear stepper drive – LKP – customer acceptance
Linear stepper drive – LKP – detail of a lifting rod
Control rod drive mechanism test stand
