[en] The possibility of diverting D₂O for use in clandestine reactors capable of weapons grade nuclear material production has created interest in safeguarding D₂O. As part of a program to investigate the technological aspects of safeguarding D₂O, several proposed nuclear based non-destructive measurement methods have been proposed which do not require the D₂O containers to be opened. These nuclear techniques all proved workable and could lend themselves, in principle, to field application. They are neutron transmission measurements, neutron capture gamma detection, photoneutron production, and measurements of the lifetime of neutrons injected in the barrel. Since much of the instrumentation is common to several methods, more than one technique may be employed to give added assurance. 6 figures, 2 tables