Product Description

The GE BWR Main Steam Isolation Valve (MSIV) sits on each main steam line penetrating primary containment and closes rapidly on demand to isolate the reactor. According to publicly filed asbestos litigation records, MSIV body-to-bonnet joints, disc-seat sealing surfaces, and associated pneumatic actuator assemblies allegedly used asbestos-fiber sheet gaskets and asbestos-fabric insulation pads to survive main-steam temperatures. Removable insulation blankets wrapping the valve body were allegedly sewn from asbestos textile. Grinding old gasket residue off flange faces during outage repacking allegedly generated respirable asbestos dust.

Workers Exposed

Nuclear plant pipefitters and steamfitters allegedly performed MSIV gasket and packing replacements. Nuclear plant mechanics and I&C technicians allegedly serviced the pneumatic actuators and limit switches mounted to the valves. Operators and refueling outage contractors allegedly worked near open MSIV assemblies during isolation logic testing.