The mobile solidification system (MOSS) is an in-drum mixer to solidify radioactive waste. In the cementation process, the waste, water and additives are dosed from a tank into the drum at the waste loading station. Then, the waste-loaded drum is transferred to the in-drum mixer, where cement is added and mixed with the waste. The cementation process using the in-drum mixer takes approximately 60 minutes (excluding drum handling). Because mixing is done in-drum, there is no chance of a lost stirrer. Dosing of the liquid and solid components is separate and a special mixer coating provides for better cleaning.