Background
As plants age, inevitably the high pressure seal fittings on the thimbles and conduits of the seal table are used — and sometimes misused — requiring the complete changeout of the fittings and ferrule sets.
BCP can refurbish (remove and replace) the high pressure seals, and it has been proven that these fittings can be safely replaced in the same locations with optimum results: ZERO LEAKAGE. It is unnecessary to shorten the thimbles or use deeper bore thimble and conduit fittings to avoid leakage.
BCP seal table high pressure seal refurbishment personnel use special tools and procedures to remove and replace the Swagelok tubing compression seal (5/8″, 3/4″, and 5/16″ sizes) ferrule sets at the plant specified locations of the thimble-to-conduit seal table locations.
This picture shows the tool as it is used for ferrule removal. Take note of the“thimble extension” that is inserted into the top of the thimble to enable the tool to guide above and below the cutting wheel.
The BCP method of refurbishment of the high pressure seals consists of :
- Providing the special refurbishment tooling, adapters, guides, gauges, and procedure for removal of the old Swagelok ferrule sets from their originally installed upper, middle, and lower seal locations.
- Polishing and reconditioning the seal surfaces.
- Replacing the components of the 5/8″ or 3/4″ conduit x 5/16″ thimble Swagelok reducing unions and the 5/16″ tube Swagelok flare unions.
The new 5/8″ and 3/4″ conduit lower high pressure seal ferrule set and nut replacement requires the complete removal of the middle and upper 5/16″ tube ferrule sets and components. New replacement connector components and seals are provided by the plant and installed by BCP to produce excellent sealing for the high pressure reactor operating conditions at the specified seal table thimble-to-conduit.
This closeup shows the adjustable top V guide that enables variable clearance adjustment as the cutting wheel wears down. This adjustment allows us to keep a one to two mil clearance between the wheel and the thimble wall, while enabling the ferrule to be slit apart and removed.
Description of Service
BCP designs and manufactures the special tooling and adapters used in these carefully performed ferrule removal and replacement operations. Each set of adapters for thimble and conduit extensions are custom fitted to plant specific dimensions. Site work is performed by a three or four-man crew on a single shift, or a full 24-hour around the clock critical path time frame. The seal removal operation is theoretically simple to perform, but is very conscientiously controlled due to the close clearances required. Only the most experienced personnel are approved for these removal operations.
The new seals are made up so that the thimble height is set to exactly match its pre-refurbishment position for consistent remake-up to the guide tube rack jumper tube connections. This height setting is the single most frustrating and time consuming experience that plant personnel are faced with when they have allowed others to make thimble height adjustments. They find upon reassembly that the rack won’t seat properly due to different thimble heights. Variances as little as 1/8” cause substantial misalignment.
This attention to detail is what sets BCP above the competition.
Experience
BCP High Pressure Seal Refurbishment tooling and procedure has been used for a total of over 1400 seals refurbished with 100% success (no leakage). In just the last two years, we’ve completed successful refurbishment projects at Turkey Point, DC Cook, Shearon Harris, Vogtle, and Ginna.
Click Here to Subscribe and receive the latest job postings and news directly to your email inbox!
