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Power Jacks has revealed that a specially designed electric linear actuator unit is being used in a machine designed to carry out reactor core inspections at nuclear power stations.

Reactor core inspections of nuclear reactors is an essential function of operating a nuclear power station that must achieve the highest quality to ensure continued power supply with the best plant safety and efficiency.

A key part of the maintenance programme is the inspection of the nuclear reactor cores.

To perform this operation a specialist machine with TV inspection and bore measuring is used.

The machine is lowered to engage with the reactor standpipes by an electric linear actuator supplied by Power Jacks.

The machine is called the NICIE (New In-Core Inspection Equipment).

It was developed by BNS Nuclear Services with whom Power Jacks worked to design and manufacture the main linear actuation unit engaging the machine with the reactor standpipe.

Four additional jacks act as stabilisers when the machine is coupled to the standpipe.

The NICIE inspects nuclear reactors by lowering a camera down into the reactor fuel channel to provide measurement and maintenance checks.

The main body of the machine is raised and lowered to engage it with the reactor stand pipes.

A specially designed electric linear actuator from Power Jacks performs this actuation.

The actuator is designed to lift and lower the 20kN load over a stroke of 525mm with the end of travel signalled by proximity sensors installed in the actuator.

To maintain a rigid column over the stroke the actuator has two internal guidance mechanisms for the ram.

As a safety feature the ram is fitted with a proprietary clutch to act as a mechanical fail-safe to prevent an overload condition should external control systems fail.

Powering the actuator is a 0.75kW motor with integral brake for position holding and an auxiliary hand drive shaft should manual operation be required.

The machine itself is mounted on wheels for easy transportation.

However, when positioned for use, four screw jacks at the base of the machine take the weight off the wheels similar to stabiliser jacks on mobile cranes.

Hinckley Point Power Station will be operating the hoist, currently being tested by BNS Nuclear Services at Whetstone in England.

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