Cleaning Machines

Increasing functionality by cleaning the connecting elements of primary circuit components

Cleaning machines and sets are further products in our product range. Gentle and efficient cleaning of the connecting elements reduces material wear and increases the service life.

NIS cleaning machines perform dry cleaning with brush heads. The brush heads are easy to handle, electrically or pneumatically driven and equipped with a suction device.

Our cleaning equipment includes:


  • cleaning kits for internal and external threads,

  • cleaning equipment for RPV (Reactor Pressure Vessel) thread holes,

  • cleaning equipment for RPV bolts,

  • cleaning equipment for RPV nuts.


Example of operating principle for Cleaning device for threaded RPV holes:

  • Precise guidance of the cleaning head in the threaded hole - crane not required due to low weight (46 kg).

  • Thread cleaning is performed by lifting and lowering the rotating and adjustable cleaning head.

  • Particle extraction via vacuum suction through a tube installed centrally in the cleaning head.


Stud hole cleaning device

We have recognized, based on the experience feedback from our customer service department, the need to carefully maintain and inspect the blind hole threads of the reactor bolts. This involves cleaning the threads of the blind holes from the hardened grease so that you can inspect the threads and, if necessary, rework them if they are damaged to ensure that the reactor bolts can be screwed in safely and without problems.

You can choose between simplified cleaning equipment and automated cleaning machines.

The simplified version of the stud hole cleaning machine works with a purely pneumatic brush module. Here, the brush head is pneumatically driven and the lifting movement is performed by a pneumatic cylinder. The device is placed on the reactor vessel flange by two persons and operated on site. In addition to the cleaning device, a suction device must be connected during the cleaning process. Moving the unit from one blind hole to another is done manually. Moving by means of a rotary crane is also possible. The appropriate attachment points for transport are provided on the cleaning device.

Furthermore, NIS has developed a stud hole cleaning machine in a modular design in order to adapt the machine to the specific requirements of the clientele. The stud hole cleaning machine is controlled and operated from a control panel located at the edge of the reactor pit. The modules of the blind hole cleaning machine are built on a self-propelled platform. The traversing of the platform is automated by means of two walking gears attached to the right and left sides of the platform. Traversing and positioning on the reactor vessel is carried out in such a way that it is ensured that the machine stands in a tilt-proof position during traversing or cleaning.

The electrical cabinet with the control equipment is mounted on the platform. Furthermore, the suction device with the HEPA filter is also mounted on the platform. The suction device is directly connected to the brush module, so that the dust particles that occur during dry cleaning are sucked off directly via the brush head.

The suction device prevents contaminated dust particles from entering the environment and thus being carried away. Stainless steel or nylon brushes can be used, depending on customer requirements.

Other options for stud hole cleaning would be a thread inspection module (high resolution camera) and a module for greasing the stud hole threads. The two modules are built on a separate platform so that the inspection or grease module does not interfere with the cleaning process of the stud holes.