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Hilti diamond systems
in atomic power plants
The controlled demolition of
atomic power plants is a complex
and demanding operation.
Projects of this kind often have
to be undertaken by companies
with specific experience in this
field.
Hilti has decades of experience with diamond systems
for cutting, grinding and coring. But controlled demolition
in atomic power plants not only demands
comprehensive know-how, contractors also often need
special solutions for complex tasks that cannot be carried
out using standard tools and equipment.
One example of a job that required a specially
manufactured solution was a project carried out by
the company Norbert Braun GmbH of Münster,
Germany. A stainless steel vapour drier in a reactor had
to be cut into several sections to allow it to be packed
in radiation-tight containers. Braun’s concept involved
placing the vapour drier inside formwork and filling
the formwork with a special low-viscosity concrete
before subsequently using a wire saw for the cutting
process. The water-cooled sawing operation was
monitored by cameras and remotely controlled so that
the time spent by the workforce within the hazardous
radiation zone could be kept to a minimum. This was
an extremely demanding and innovative procedure,
for which Norbert Braun GmbH recently received
the “Diamond Award 2009” from the International
Association of Concrete Drillers.
Hilti supplied a special high-capacity diamond
wire saw system for the project, featuring a higher
power output, a pneumatic wire tensioning system
and continuously adjustable wire speed control. With
this equipment Braun was able to prevent sudden
rises in the tension on the wire and greatly reduce the
risk of wire breakage. In addition, Braun used special
diamond wires supplied by Hilti in three different
diameters, which allowed trouble-free completion
of each cut.
Pioneering role in dry cutting
Project engineering with tailor-made
solutions makes Hilti a reliable partner
for controlled demolition in atomic power
plants. The photo shows an automatic
drilling system developed by Hilti in use
on a concrete container.
Other methods of controlled demolition in atomic
power plants make use of dry cutting techniques.
In 2002, Hilti was one of the first companies to
supply dry-cutting wire sawing solutions for demolition
work in atomic power stations. This technique
allowed considerable cost-savings when removing
contaminated concrete or steel structures as the costly
and time-consuming task of sealing off the cutting
area and the evaporation processes required for the
disposal of contaminated concrete slurry were no
longer necessary.
As part of a demolition project in 2008 at a reactor
in Germany a Hilti dry-cutting diamond wire saw was
used to cut an access opening in a curved concrete wall
to allow removal of material from the reactor core.
Comprehensive range of products
Hilti diamond systems provide a broad range of
solutions incorporating dry-cutting techniques for
use on reinforced concrete and steel. These include
diamond wire saws with continuously variable speed
control, adjustable wire guidance systems and highperformance
diamond wires.
The know-how incorporated in Hilti diamond systems
is in big demand for technical demolition in
atomic power plants, especially with the dry-cutting
technique.
Hilti also supplies a range of core drilling machines
and dry-cutting core bits featuring the innovative polycrystalline
diamond technology. Core bits of this type
achieve higher coring performance than conventional
segment-type core bits, and only one specification is
required for use on various types of concrete.
For surface decontamination Hilti recommends
hand-guided diamond grinding systems in conjunction
with the appropriate vacuum removal system for dry
dust. These power tools, discs and appliances have been
developed together to form matched systems providing
high suction performance.
Individual solutions
Hilti is also a source of support provided by teams of
engineers with experience of controlled demolition
projects in atomic power plants. The manufacturing
of special solutions and customization of standard
tools and equipment for special jobs is also a field in
which Hilti excels. Hilti’s specialists can also provide
technical advice, training and repairs where protective
measures against radiation are essential.
www.hilti.com
Is s u e 1 - 2009 • Fe b - M a r c h • PDi 23