Study on the Reliability Improvement of a Mechanical Seal for the Primary Loop Recirculation Pumps (PLR Pump)

Primary Loop Recirculation pump (PLR pump) for Boiling Water Reactor (BWR) uses a mechanical seal as a shaft seal device, which the seal material is made of a ceramic. Recently, a new ceramic suitable as a seal material has been developed. We will explain about the introduction of the material to a mechanical seal for the PLR pump. First, we checked the material characteristics of the ceramic. Next, we carried out the abrasion acceleration test at the mechanical seal test facility for PLR pump, and performed an analysis of seal face deformation for the applied ceramic. Then, we performed a full scale test that simulated the operation pattern of the PLR pump. As a result, we confirmed that the new ceramic property suits for the use as a mechanical seal for the PLR pump.