  At the 120-GeV proton accelerator facilities of Fermilab, USA, water samples
were collected from the cooling water systems for the target, magnetic horn1,
magnetic horn2, decay pipe, and hadron absorber at the NuMI beamline as well as
from the cooling water systems for the collection lens, pulse magnet and
collimator, and beam absorber at the antiproton production target station, just
after the shutdown of the accelerators for a maintenance period. Specific
activities of {\gamma} -emitting radionuclides and 3H in these samples were
determined using high-purity germanium detectors and a liquid scintillation
counter. The cooling water contained various radionuclides depending on both
major and minor materials in contact with the water. The activity of the
radionuclides depended on the presence of a deionizer. Specific activities of
3H were used to estimate the residual rates of 7Be. The estimated residual
rates of 7Be in the cooling water were approximately 5% for systems without
deionizers and less than 0.1% for systems with deionizers, although the
deionizers function to remove 7Be from the cooling water.
