A NEW ESTIMATE OF ATMOSPHERIC C-14 DISCHARGES FROM SELLAFIELD

UNSCEAR has estimated that C-14 discharges from the nuclear fuel repro cessing plant at Sellafield are responsible for about a quarter of the total global release of this radiologically important radionuclide. R eported discharges from the site have been based on direct monitoring of the effluent since 1978. Prior to that date, however, discharges ha ve been estimated from the measurement of C-14 levels in the annual gr owth rings of a locally grown tree. In the present study, discharges p rior to 1978 have been re-calculated based on new measurements of C-14 levels in tree rings. The results indicate that C-14 discharges from Sellafield prior to 1978 were significantly lower than previously thou ght, 124 TBq as opposed to 207 TBq. The total release of C-14 to the a tmosphere from this site from the start of operations up to 1995 is no w estimated to have been 244 TBq. (C) 1998 Elsevier Science Ltd. All r ights reserved.