Discharges to the environment from the Sellafield site, 1951-1992

Abstract

The history of liquid and atmospheric discharges from the Sellafield nuclear complex in Cumbria, UK over the period from 1951 (the start of operations at the site) to 1992 has been reviewed. The chronology of liquid effluent discharges is essentially unchanged from previously published figures, but the chronology of aerial effluent discharges has been very substantially amended, reflecting the results of experimental work to assess the efficiency of aerial effluent sampling systems on the site, the analysis of previously unreported data on plant based measurements of aerial effluents in the 1950s, and a number of other factors. The amended discharge chronologies have been validated by reference to the extensive environmental monitoring data which are available for the Sellafield site, comparing environmental concentrations predicted from the discharge chronology and environmental models with those actually measured. The revised discharge chronologies together with the model account for all the major features of spatial and temporal variations in environmental concentrations of radionuclides in the vicinity of the site, but overestimate the body content of plutonium in local residents compared to the limited number of available measurements. The revised discharge chronologies do not lead to any major changes in the assessed lifetime doses to local residents and do not alter the conclusion that doses from discharges appear to be far too small to account for the excess of childhood leukaemia in the local village of Seascale.

Record of anthropogenic impact on the Western Irish Sea mud belt

“…These radionuclides correlate with records of radioactive discharges from the Sellafield power plant Gray et al, 1995) (Fig. 7).…”

“…6 and 7), it is possible to interpret the first detectable amounts of 137 Cs as correlating with the beginning of operations at the Sellafield power plant in 1952. Following this trend, the prominent peaks at 30 cm and 25 cm depth in Core 1 and Core 2, respectively, equate with the peak in Sellafield 137 Cs discharge in 1978 (Gray et al, 1995). Similarly, sub-maximum peaks in both cores correlate with a period of increased discharges in the early 1970s, preceding this 1978 peak.…”

“…It is one of two such Mud Belts within the Irish Sea that mark areas where deposition is the dominant process under a low energy regime (Dobson, 1977;Pantin, 1977;1978) ( Fig.1). The second of these Mud Belts is located just offshore from the Sellafield nuclear complex (located in Cumbria, west coast of the UK), which has been discharging low-level waste into the Eastern Irish Sea Mud Belt (EISMB) since 1951 (Gray et al, 1995) (Fig. 1).…”

“…The annual mean discharge from Sellafield in 1986 for 137 Cs was approximately 100 TBq . The decline in 137 Cs levels in the top portion of each core also corresponds with an overall decrease in discharge from Sellafield after 1978 (Gray et al, 1995). Therefore, considering the top of the cores as representing 2009 (year of collection), it is possible to calculate an average apparent sedimentation rates of 2.7 cm a -1 and 2.1 cm a -1 for the time interval of 1952 -1978 in Core 1 and Core 2, respectively.…”

Spatial trends on an ungrazed West Cumbrian saltmarsh of surface contamination by selected radionuclides over a 25 year period

“…The liquid effluents contained actinide and fission elements which are discharged 34 via pipeline and are comprised of the purge water from waste storage ponds and process liquors 35 from spent fuel reprocessing. Discharge histories showed the activity concentrations for 36 radionuclides including 137 Cs, Pu-α and 241 Am reached a maximum in the 1970s and then 37 substantially declined (Gray et al, 1995). 38…”