237Np/129I atom ratios in the Arctic Ocean:: Has 237Np from western European and Russian fuel reprocessing facilities entered the Arctic Ocean?

Radioactive waste discharges from European nuclear fuel reprocessing facilities have introduced a suite of radionuclides (Sr-90, Tc-99, I-129, Cs-134, and Cs-137) into the Arctic Ocean by advection of North Atlantic water through the Norwegian Sea and Fram Strait. Measurements made in 1994 of Np-237 (T-1/2 = 2.14 x 10(6) year) and I-129 (T-1/2 = 15.7 x 10(6) year) in surface waters (0-300 m) of the Arctic Ocean show a strong linear correlation in their concentrations below the Polar Mixed Layer (30-50 m) indicating that Np-237 discharged from these same facilities (principally Sellafield) has entered the Arctic Ocean. Budget calculations indicate that global fallout carried with runoff plus dischargers from Russian reprocessing facilities have contributed Np-237 to the upper Arctic Ocean in about equal proportions, but their combined total is less than half that from Sellafield. Fallout from the Chernobyl accident added insignificant amounts of Np-237 and I-129 to the Arctic Ocean compared to discharges from Sellafield and La Hague. (C) 1998 Elsevier Science Ltd. All rights reserved.