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NuclearPlantJournal.com Nuclear Plant Journal, July-August 2016
Fig. A: OEM casting variations in spare parts cause pump to miss design requirement
quality surface finishes were specified
and the assembly processes optimized.
The packing box was redesigned for a
seal-less construction. The corrosion
of the foundation was mitigated by
implementing a HydroSeal design
which allows any water to leak before
reaching the packing box. Size and
shape constraints also were considered
because the new pumps would have to be
assembled in the existing pit hole, limiting
the maximum allowable pump size.
Technology used in
design, prototyping, and
fabrication:
Prior to the development of certain
technologies and computer-aided analyses,
a custom pump such as this would have
been financially unfeasible, and certainly
would not have been possible to develop
from concept to finished product in just
16 months. During that short time frame
Hydro was able to create a fully-functional
prototype that could then be tested to ensure
that it would perform as needed as well
as manufacture the final deliverable. [See
Diagram 1] In addition to manufacturing
the pump, Hydro’s team developed a
comprehensive installation and operation
manual to accompany the pump.
Among the technologies applied
in this innovative solution were 3-D
printed sand molds and cast-flow
simulation software. 3-D printed molds
have revolutionized the custom-foundry
side of the pump industry allowing cost-
effective casting of complex parts with
rapid turnaround time. The solidification
modeling that casting-flow software
facilitates ensures that the castings will
be high quality and allow for virtual
prototyping that enables changes to
the mold designs before any metal is
poured. Both of these innovations have
greatly reduced the kind of trial and
error processes that cost money and take
time when developing a new product.
The overall cost of the finished product
is reduced, and the delivery window is
improved.
Quick delivery time for a
complicated material:
Due to the nature of the corrosive
cooling media, the customer decided to
have the new pump manufactured out of
AL-6XN stainless steel. This required
sourcing material that met the stringent
ASME Section III criteria. AL-6XN
has a proven track record for corrosion
resistance (it is often used in seawater
applications), 50% greater strength than
standard stainless steel, and the capacity
to be welded and machined. Delivery time
on this material can often be quite long,
Custom-Built...
