The behaviour of plutonium and americium in the shoreline waters of the Irish Sea: A review of Harwell studies in the 1990s

Diagenetic reactivity of the plutonium in marine anoxic sediments (Cumbrian mud patch - eastern Irish Sea)

“…Overall, an estimated 120TBq of 238 Pu, 611TBq of 239, 240 Pu and 22 PBq of 241 Pu have been discharged to the Irish Sea during the period 1952-2000 [1]. Most of the so-called conservative radionuclides are advected northwards and leave the Irish Sea via the North Channel [2], with a smaller proportion being dispersed southwards to the English Channel approaches [3]. In contrast, radionuclides having a strong affinity for sediment particles are quickly removed from the water column by scavenging processes [4][5][6] onto suspended particulate matter, and accumulate in fine-grain deposits.…”

Influence of seasonal circulation on flushing of the Irish Sea

“…Further studies carried out by Jefferies et al (1982), McKay and Baxter (1985) and McKay and Pattenden (1993) delivered estimates of between 12-18 months.…”

“…They enter the region through both the St. George's and North Channels, with the two paths meeting along a line running westward from the south of the Isle of Man (location T15 in Figure 1) (McKay & Pattenden, 1993), where tidal currents are exceptionally weak (< 0.3 m/s) (Hill et al, 1996). Currents of 1-1.5 m/s are usually observed during mid-ebbs and mid-floods in the North and St. George's Channels, where most of the tidal energy is dissipated (MacDowell, 1997).…”

A Comparative Study of the Speciation and Behaviour of Plutonium in the Marine Environment of Two Reprocessing Plants

“…Preliminary experiments, with unfiltered sea water sampled in the near field, show that plutonium present in an oxidized state in sea water is genuinely soluble (no retention is ob- distances from th discharge point are counted negatively to the west and positively to the east, in the Channel, and counted negatively to the south-west (data from [11]) and positively to the north-west (most of the data from [5]) in the Irish Sea. served even by a 1 kDa ultrafilter), while plutonium in a reduced state is retained in increasingly significant quantities by progressively lower NMWLs ultrafilters (Fig.…”

“…The twice-daily tide-induced watermass excursion is ~10km (peak tidal currents velocity: 0.5 ms" 1 ) and is thought to be responsible for the dispersal of the effluent. Effluent advection, on the other hand, appears to be driven by residual currents with velocities in the range 0.1-0.5 cm s 1 [5].…”