During last Fall’s outage season, Preferred Engineering assisted with the installation of
a set of brand-new Hot/Cold Leg Loop Plugs. The process went smoothly thanks to an
outstanding product as well as excellent cooperation and planning with our customer to
develop and document a streamlined approach.

While loop plugs may not require frequent installation, their role in nozzle isolation for
Pressurized Water Reactors (PWRs) is critical. Designed for Hot and Cold leg
applications, Preferred’s loop plugs provide a reliable and secure method of isolating
large-diameter piping, while minimizing protrusion from the vessel wall.

What sets PE’s loop plugs apart is a combination of smart engineering and practical,
field-informed design. They feature:

• a low-profile configuration that protrudes only slightly from the vessel wall, reducing installation complexity in tight or obstructed spaces.
• manual actuation with a simple torquing process, eliminating the need for hydraulic or pneumatic tools and reducing the risk of mechanical failure.
• a secondary inflatable seal for added redundancy and security.

Even the best equipment requires a well-planned procedure for safety and efficiency. In
the case of PE’s recent loop plug installation, the customer worked closely with PE to
understand the loop plug function in advance of the outage. Together, we developed
and documented a detailed installation process, allowing both plugs to be installed in
under four hours, with no unexpected issues.

The key takeaway from this project: documented procedures are essential. Without it,
practical knowledge and valuable insights from prior installations can be lost, forcing
future teams to start from scratch.

Loop plugs serve as a strong example of what can be achieved when quality equipment
meets proactive planning and shared expertise.

For more information on PE’s Loop Plugs, take a look at our Loop Plugs product page.