A low head safety injection pump rotor seized in its casing, bringing a
nuclear power plant to critical operation status and requiring emergency
repairs. Hydro’s Chicago nuclear qualified repair service center was
engaged to work on the pump 24/7.
From decontamination all the way
through testing, Hydro’s engineering and operations team responded quickly,
providing a lasting solution at a critical time. Flexibility, qualified and thorough
engineering analysis, and essential resources led to fast and reliable uptime
– and a very satisfied customer.
HydroAire Inc., A Hydro Company l
Chicago, IL
800.223.7867 l
Emergency Response
Is What We Do.
Engineering Expertise
Is How We Do It.
Critical Pump Seizes
Rotor was damaged due to pump running
dry for approximately 30 minutes.
Pump Decontamination
and DCI
While the damaged pump was being
decontaminated at a dedicated facility,
numerous spare parts from the plant's
inventory were reviewed by Hydro's
engineering team. Equivalencies
such as dimensional and functional
conformity were studied.
Spare Parts Analyzed
A spare OEM impeller supplied by the
customer ostensibly manufactured to
the same pattern and drawing
numbers initially appeared to be a
drop-in replacement. However, upon
close inspection, Hydro's engineering
team discovered the OD and vane
underfiling geometry deviated from
the OEM's specs. Expected loss of
hydraulic performance due to this
deviation was calculated and brought
to the customer's attention, with
suggested additional improvements.
Diminished Axial Float
Diagnosed/Adjusted
While analyzing the pump assembly,
engineers noted that the impeller's
overall exit width was larger than
spec, obstructing lowering of the
casing's upper half. To meet the
drawing requirements, machining
the shroud was recommended.
Evaluations and justifications
confirmed that the original design's
mechanical strength, axial thrust,
and hydraulic performance would
not be negatively impacted.
Final Testing and
Turnaround
Hydro’s performance test lab had
been on standby throughout the
repair process, with the preliminary
test layout. When repairs were
completed, the pump was
immediately tested and approved by
the customer. The pump was shipped
to the customer only eight days after
its arrival, and was up and running
immediately after successful results
of pre-service tests.
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