Northern European Seas environment has different sources of radionuclide contamination, both natural and artificial. In present work the radionuclide content of sediment samples (obtained in 2016-2018) of Keret Bay of Chupa Estuary, Kandalaksha Gulf of a semi-enclosed Arctic sea - White Sea, Russia has been studied. Keret Bay is a small semi-isolated tidal estuary in the South-West part of Kandalaksha Gulf. The mouth of Keret river affected by strong tidal motion and spring flood. We have taken sediment samples in two sites in this estuary, one in the mouth of Keret river and second at the shoe side of one of the straits of estuary. Collected sediment samples were originated from bottom of small unnamed rivulet and Keret river. Samples consist of sand, gravel and silt with the low content of detritus. The radionuclide analysis of the samples was done by using of ORTEC High-Purity Germanium Coaxial Detector System with high energy resolution. For the verification of the obtained results also the Ge-Li detector with the low background shielding has been used. The measurements were performed for seven samples. The information about natural radionuclides and also about artificial nuclide contaminations has been obtained.