Inspections at several PWR plants have revealed a potential safety hazard caused by leakage around the nozzle penetrations on the reactor vessel top head. Left unchecked, a resulting nozzle ejection or RPV head rupture could cause a loss of coolant accident. Because of this situation, the NRC now mandates bare metal vessel head inspections for all US nuclear power plants in addition to normal in-service inspections.

The original reactor vessel top head insulation was never designed to accommodate the visual inspections now required by the NRC, and its semi-permanence is problematic. Removing the old top head insulation is time-consuming and increases personnel dose levels. The process can also damage instrumentation. So to facilitate the new inspections and prevent problems associated with future inspections, Transco offers a two step solution.

Trust Transco

First, Transco has the experience to safely and effectively remove the old insulation once considered to be permanent. Second, Transco will custom design metal reflective insulation tailored to the specific geometry and inspection needs of each vessel head. This new insulation can be easily removed for visual and NDE inspections.

Transco’s experience in the replacement of old insulation with new removable insulation is unparalleled. Our expertise extends across a range of plant requirements including shroud clearance, airflow and thermal inspection locations and vessel head geometries. To date we have provided solutions for:

• 39+ U.S. Reactor Top Head Insulation Projects
• 5+ U.S. Reactor Vessel Bottom Head Insulation Projects
• 8 International Reactor Vessel Top Head Projects