A nuclear power plant had numerous valves in both the steam and boiler feed water systems operating at high temperature and pressure. Pressure seal type valves in this service rely on the system's pressure to activate the "pressure seal" on the valve. During use, the pressure seal ring, which is the sealing element, may be damaged by corrosion, wear, or deposits. When this happens the valve leaks, requiring costly replacement of the seal ring, machining of the seal seat, or replacement of the valve.

The customer was looking for a quick, economical way to repair the plant's leaking pressure seal valves and get them back in service.

The utility's research lab tested Hi-Pro Seal^® and found it had good physical properties for use in hot water and steam. However, plant personnel wanted to test Hi-Pro Seal^® before utilizing it plant-wide.

Three leaking pressure seal valves were chosen to test Hi-Pro Seal^®. Two of the three valves, when disassembled, showed visible pitting, corrosion, or wear on the seal ring. Hi-Pro Seal^® was applied to those valves with pitted and corroded seal rings before re-assembly. The third valve showed no visible defects; so, it was reassembled without application of the compound. When the three valves were put back into service, the two treated with Hi-Pro Seal^® performed without leakage. The third valve that had no visible defects leaked as before. The leaking valve was again taken out of service, it's seal ring coated with Hi-Pro Seal^® and successfully put back on-line; this time with no leakage.

The plant then incorporated Hi-Pro Seal^® into regular maintenance applications.