Synthesis and characterisation of brannerite compositions (U<sub>0.9</sub>Ce<sub>0.1</sub>)<sub>1−x</sub>M<sub>x</sub>Ti<sub>2</sub>O<sub>6</sub> (M = Gd<sup>3+</sup>, Ca<sup>2+</sup>) for the immobilisation of MOX residues
RSC advances