Investigation of friction units of nuclear plants operating in heavy high-temperature liquid-metal heat carriers. Part 2. Experimental results

Abstract

The tribological problems posed by heavy liquid-metal heat carriers used in the circuits of nuclear power plants are discussed. The results of experimental study of the vibrational wear of heat-exchanging tubes in the interfaces with the spacing grates are presented. These results are applicable for testing the vibrational strength of the steam generator of a fast neutron reactor with lead heat carrier. Experimental investigation and service-life tests of involute-profile cylindrical tooth gears and sliding bearings working in fast neutron reactors containing the lead heat carrier are conducted. Experimental and theoretical study is performed on the wear of steel and cast-iron sliding bearings in the recycling pumps of reactors operating in lead, eutectic lead-bismuth and lead-lithium alloys. It is shown experimentally that the tooth gears from 40X13 steel and SCh20 grey iron are capable of operating in the lead heat carrier for 500 and 400 hours, respectively, at the temperature 450°C when the concentration of thermodynamically active oxygen in the lead is close to saturation, the contact stress in the gearing is 758 MPa, the gear rotational frequency is 500 min−1 or less, and the gear ratio is 1.5 (the peripheral velocity of the gear and the wheel over the pitchline is 2.1 m/s). The likely causes of destruction of the gear teeth are adhesive wear and insufficient heat resistance (refractorability) of the tooth material at 450–500°C.