A method of assembling a pump for use in a radioactive environment includes positioning tubing between a rotor and a clamp of the pump. The pump includes a pump head that includes a casing, the rotor, and the clamp. The rotor rotates in relation to the casing. The method also includes rotating the rotor for a first period to compress the tubing against the rotor. The tubing is in a dry condition throughout the first period. The method further includes directing liquid into the tubing and rotating the rotor for a second period to compress the tubing against the rotor and direct the liquid through the pump head. The method also includes calibrating the pump.