Mechanical Analyses Of The Cans In AP1000 Reactor Coolant Pump

As one of the most significant parts in canned motor reactor coolantpump, the cans means a lot to the normal operation of the primary loop ofthe plant. The cans are equipped inside the motor, influenced by rotarymagnetic field and coolant flow field. The cans tend to break for thecomplicated loads. There are few academic achievements on cannedmotor pump published, due to its special application field. The purposesmainly focus on the factors which have extreme influence on fatigue lifeof the cans, action style, and mechanical function on the cans.Main contents of this paper are as follows:Investigate on the research achievements of design, manufacture,and installation in canned motor pump, also the methods of theoreticalcalculation on magnetic field inside induction motor and mechanicalproperties of thin-wall at home and abroad.Based on the given data and structure of canned motor reactorcoolant pump, primarily designed detailed sizes by the empirical formula.The design meets the qualification of canned motor reactor coolant pumpin power and performance.Analyze on 2D harmonic field inside the motor of canned motorreactor coolant pump to get the distribution of magnetic field inside, andcircumferential distribution of magnetic induction, ampere density,Lorentz force on the cans. They are all periodic arrays. Tangentialcomponent of the Lorentz force is an overwhelming majority. Amperedensity and Lorentz force in stator can are about 35 times larger thanthose in rotor can.Analyze on 3D harmonic field at the end of the motor of canned motor reactor coolant pump to get the distribution of magnetic field there,and axial distribution of magnetic induction, ampere density, Lorentzforce on the cans. The Lorentz force on stator can decreases with distanceto the end of stator iron core. The rate is larger by 3×108 N/m when awayfrom stator iron core. At the edge of stator core, Lorentz force falls to105N.On the basis of gotten distribution of magnetic field inside the motor,calculate various losses in motor, ampere density and Lorentz force ofdifferent thicknesses (0.381mm, 0.5mm 0.6mm 0.7mm) of stator can. Theresults show that ohm loss in stator can increases with thickness of thecan with the rate of 3.12×106 W/m. Ohm loss and iron loss in rotor can,iron loss and Lorentz force in stator can are not sensitive to the thicknessof stator can. Ampere density in stator can decreases with the thickness.Analyze on 3D steady flow inside the motor of canned motor reactorcoolant pump to get distribution of pressure and temperature on surfacesof stator can and rotor can. Except area around the inlet, pressure andtemperature decrease with distance to the outlet. The temperature of theoutlet in the model is 347K, which is actually in the range of bearingsnormal operation. The wall shear stress on surfaces of stator can and rotorcan keeps steady, except some turbulence around the inlet. At the meantime, boundary layer plays extremely important role in the flow field.By all the analyses above, the failure pattern of the cans is known.Analyze the stress on the cans of canned motor reactor coolant pump tocompare with yield strength of Hastelloy C276. The results show that thepart of cans inside motor is safe.