Environmental impact of particles emitted from windscale piles, 1954–1957

Abstract

During 1954-7 particles of irradiated uranium oxide were emitted from the Windscale Piles. The particles were large compared with most ambient aerosols, 85% by weight being between 10 and 100 micron diameter, and they mostly fell within a few kilometers of the works. From measurements of activity in soil in 1958 onwards, it is estimated that about 12 kg of uranium, 20 Ci of 137Cs, 18 Ci of 90Sr and 0.3 Ci of 239+240Pu were emitted. To estimate the concentrations of 90Sr and 137Cs in milk during the emissions, comparison is made with the fallout of fission products from bomb tests, which also began in 1954, but continued longer. It is calculated that the average level of 90Sr in milk at Seascale, 1954-7, was 36 pCi per g Ca, with higher concentrations, 100-200 pCi (g Ca)-1, in milk from farms immediately surrounding the Windscale plant. For comparison, in 1963/5 the average level of 90Sr in milk in the UK was 20-30 pCi (g Ca)-1, with 90-170 pCi (g Ca)-1 in milk from certain hill farms. Since the oxide particles were larger than those derived from bomb tests, and the conditions of deposition different, an extended review is given (Appendix 1) of the factors determining the entry of radioactive or stable contaminants from fallout into food chains. It is concluded that the oxide particles would have been less efficient in this respect than bomb fallout, mainly because their relatively large size and high density would have given impact velocities sufficient to cause them to bounce off leaves, leaving little activity on the edible herbage. For this reason, the calculations are on the safe side.

Radionuclides released to the environment following nuclear events

“…As history has shown, radioactive particles are released more often than was previously anticipated, and releases of radioactive particles containing refractory radionuclides should be expected following nuclear accidents in the future. A significant fraction of refractory radionuclides such as U and Pu released during high‐temperature and high‐pressure nuclear events, such as nuclear weapons tests in the 1950–1960s (e.g., Maralinga, Australia; Mururoa and Marshall Islands, in Micronesia; and Nevada, USA), nuclear reactor explosions (e.g., Chernobyl, Soviet‐era Ukraine, in 1986), and fires in nuclear reactors (e.g., Windscale, UK, in 1957) are present as radioactive particles in the environment (e.g., Crocker et al 1966; Cooper et al 1984; Chamberlain 1987; Kuriny et al 1993; Salbu et al 1998). These entities, ranging from submicrometer‐sized particles to larger fragments, can carry substantial amounts of refractory fission products, activation products, and transuranics.…”

Radioactive particles released from various nuclear sources

“…The particles were inert towards leaching with 1 M HCl [4]. Following the fire in Pile No 1 in 1957, localised heterogeneities in the environment were observed by autoradiography [20]. Particles varying within 20-500 µm were observed up 4 km from the site.…”

Radioactive Particles in the Environment

“…Windscale) (Chamberlain, 1987). Alternatively, the release of colloids and particles is associated with authorised discharges from fuel reprocessing and waste disposal (IAEA CRP).…”

“…Radioactive particles containing refractory radionuclides such as uranium (U) and plutonium (Pu) were released during severe nuclear events such as nuclear weapons tests (e.g., Maralinga, Mururoa, Nevada Test Site, Marshall Islands), use of depleted uranium ammunition (Kosovo, Kuwait), and nuclear explosions (e.g., Chernobyl) and fires in nuclear reactors (e.g., Windscale) (Crocker et al, 1966;Anspaugh and Church, 1986;Chamberlain, 1987;Cooper et al, 1994;Simon et al, 1995;Kashparov, 1996;Danesi et al, 1998;Salbu et al, , 2004. Radioactive particles have also been released in authorized discharges from nuclear installations to rivers (e.g., Krashnoyarsk, Russia), authorised discharges to sea (Sellafield, UK; La Hague, France), in air emissions during operations (Windscale, early 1950s) and released from radioactive material dumped at sea, for instance at the shores of Novaya Zemlya (Salbu et al, , 1997Kjerre, 2006).…”