POWER May 2020 - 36

SAFETY
Unique Fire Protection System
Safeguards Nuclear Plant
When maintenance is required on permanently installed fire protection equipment,
it can jeopardize safety. One nuclear power station added additional fire pumps to
ensure plant needs could be met under any circumstances.
Dave Donahue
A
mong the various types of energy
that keep a city up and running,
none demands the same level
of attention and care as nuclear power
plants. Fire presents a major hazard at
these facilities, posing an increased risk
because it has the potential to result in
serious damage that could affect the ability
of plant operators to safely shut down
the plant, causing the reactor core to
overheat and radiation to leak.
As a result, fire protection systems
at nuclear plants require routine testing
and maintenance to assure a high degree
of reliability in the event of a fire.
Other times, fire protection systems
are taken offline for repairs, equipment
replacement, or upgrades. Fire pump
failure could spell disaster for a nuclear
power plant, but regularly scheduled
testing and maintenance, as well as
emergency backup systems, help minimize
those risks.
Adhering to Fire Protection
Requirements
All nuclear power plant systems are required
to undergo periodic maintenance
and safety checks to ensure systems
are working properly. In order to comply
with enhanced fire protection guidelines
issued by the Nuclear Regulatory
Commission (NRC) in 2004, a nuclear
power plant in the southeastern U.S.
needed to maintain two working primary
fire pumps and two jockey pumps, or
it would be required to take the nuclear
reactor offline.
Even during routine maintenance,
the NRC requires that four pumps be
operational. If repairs are needed and
they cannot be completed within the
mandated maintenance window, which
is typically three to five days, regulations
dictate that the nuclear reactor
must be taken offline-a consequence
that would result in an enormous expense
for plant operators, as well as repercussions
for consumers who have
36
environment of an individual plant. This
can be painstaking and demands a
great deal of expertise.
During the design stage, it didn't take
1. Engineers designed a backup fire protection
system and tied it into a nuclear power
plant's main fire header for use during unplanned
emergencies and when permanently
installed equipment requires maintenance.
Courtesy: Xylem
come to depend on an uninterrupted
supply of power.
In order to meet NRC requirements,
the nuclear plant engaged Xylem Rental
Solutions to provide a temporary backup
fire
protection system that could
be activated when one or more of the
permanent pumps were taken offline
for maintenance (Figure 1). The customer
needed to ensure the temporary
backup fire protection system was designed
to meet the unique flow, head,
system, and operational requirements
of the plant. Additionally, the system
had to be installed quickly and needed
to comply with numerous plant-specific
procedures. Lastly, the facility needed
a guarantee that temporary backup fire
protection equipment would be available
on short notice.
Custom Solution Ensures Continuity
and Compliance
Designing fire protection systems for
nuclear power plants is not a one-sizefits-all
endeavor. Systems must be customized
based on individual plant risks,
layout and schematics, piping infrastructure,
and overall plant conditions.
In addition to addressing unique plant
configurations, custom solutions need
to maintain compliance with licensing
requirements, as well as integrate
strict NRC guidelines into the distinct
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long for Xylem engineers to conclude
that the original nuclear plant layout
was not designed to properly address
routine maintenance of the permanent
fire protection system. To resolve the
issue, Xylem Rental Solutions engaged
its dewatering application experts to design
a custom manifold that could hook
up to a flange connection on the main
fire header, enabling a temporary jockey
or main fire pump-or both-to be connected
to the system.
Based on site conditions and system
needs, the Godwin Dri-Prime HL250
and Dri-Prime HL100 pumps (Figure 2)
were selected to serve as the basis of
the nuclear plant's emergency backup
system.
The high-pressure, dieselpowered
pumping units sit on skids for
plug-and-play installation and quick removal
in an emergency water pumping
situation. The customer and Xylem also
worked together to develop a step-bystep
procedure for the installation and
testing of these temporary pumps to
place them in and out of service during
regular testing and maintenance of
the plant's fire protection system equipment
as required by the NRC.
Once the equipment was manufactured
and delivered, installation took
about a week, followed by a successful
one-day test period. Based on the outcome
of the initial project, the customer
awarded Xylem a multiyear contract to
provide fire protection pumps and ancillary
equipment on an as-needed, willcall
basis. To date, the customer has
renewed that contract annually for more
than 12 years. As part of its ongoing
contracted services, Xylem continues
to work closely with plant management
to update the facility's temporary backup
fire protection pumps as increasing
security measures dictate changes to
overall fire protection system design for
POWER | May 2020
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POWER May 2020

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