Nuclear quantum effects in water arise from the noncommutative character of momentum and position, which in turn is related to the potential energy surface onto which the atoms move. These effects are mostly prominent on the hydrogen atoms, due to their low mass. However, theory predicts a considerable quantum excess in kinetic energy for oxygen atoms in ice at 269 K, i.e. 21 meV above the classical value of 35 meV. Do these effects originate from oxygen-atom localisation of the oxygen atoms (water centre of mass) that occurs in the solid as compared to the liquid? A DINS experiment optimised for the measurement of oxygen for heavy and light water across the melting point is proposed to test the above predictions. The primary aim is to elucidate the role played in water by the local environment and ultrafast dynamics of the oxygen atom