Reactor coolant pump sealing surfaces with titanium nitride coating

摘要

A pump has a shaft and a housing containing pressurized fluid and employs a rubbing-type sealing assembly for sealably and rotatably mounting the shaft within the housing. The sealing assembly includes an annular runner mounted around the shaft for rotation therewith and an annular seal ring mounted within the housing in non-rotational relationship thereto. The runner and seal ring have surfaces facing and in rubbing contact with one another. A coating of titanium nitride is incorporated on at least one of the surfaces. The coating of titanium nitride can be deposited as an outer hardface layer on the one surface, or, alternately, as an inner passivating barrier layer upon the one surface and then a coating of chromium carbide can be deposited as an outer hardface layer on the coating of titanium nitride.