Bearing vibration during cold starting has now been remarkably mitigated by readjusting gland clearances and coupling alignment, herewith preventing the occurrence of radial gland rubbing.

The effects of gap size, heat flux and inlet subcooling on the boiling incipience, flow pattern, heat transfer coefficient, flow instability and critical heat flux were analyzed and discussed.

In cold state, excessive small gap in partial zone can cause free-clearance under thermal expansion effect and cause the copper bushing damaged.