Complex sentence: As the water serves as the solvent for the uranium salts, it serves as the fuel; as it is also the coolant it serves to cool the reactor as well, hence the name'homogeneous' (as coolant and fuel are one substance).
Split into simpler sentences: As the water serves as the solvent for the uranium salts, it serves as the fuel. As it is water, it serves to cool the reactor as well-hence the name'homogeneous' (as coolant and fuel are one substance).