Windscale Fire Research Articles

Assessment of dose rates to non-human biota from radioactive discharges from Sellafield Ltd. using PC-CREAM

PC-CREAM is a tool for assessing the radiological impact of routine discharges of radionuclides to the environment. It can be used for prospective assessments, to calculate doses to members of the public for authorisation of proposed discharges, or for retrospective assessments of previous discharges where doses are compared with dose limits. These types of assessment are a fundamental requirement of regulations governing the control of radioactive discharges. However, the latest publications of the basic safety standards for radiation protection, EU (Council of the European Union, 2014) and the IAEA (IAEA, 2014), now include the requirement to demonstrate protection of the environment as well as members of the public. To this end, a module has been added to PC-CREAM for calculating dose rates to non-human biota (Anderson et al., 2022). The methodology used for this calculation is based on the recommendations contained in ICRP Publication 108 (ICRP, 2008), which provides a general framework for protection of the environment. The additional module means that PC-CREAM can be used to assess doses to humans and dose rates to biota in an integrated way, for the same set of discharges and using the same dispersion models. This paper describes an assessment of dose rates to biota living in the vicinity of the Sellafield nuclear site, carried out using the new biota module of PC-CREAM. Historical discharges from Sellafield to the sea and atmosphere were considered for the period 1951 to 2017, excluding those from the Windscale fire in 1957. Dose rates calculated for marine biota (flatfish, crabs and brown seaweed) are less than 1 mGy d−1 and are below the lower derived consideration reference level (DCRL) for the ICRP marine reference animals and plants (RAPs). Dose rates for terrestrial biota (bees, deer, earthworms, frogs, wild grass, pine trees and rats) are less than the relevant lower DCRL for terrestrial RAPs, ie 0.1 mGy d−1. Dose rates were also calculated for a user defined organism ‘seabird’ to represent birds which inhabit both marine and terrestrial environments near Sellafield. For seabird, the lower DCRL of 0.1 mGy d−1 is exceeded throughout the 1950s, 1960s and 1970s, when the discharges were at their highest, due to exposures from the marine environment. Since the mid-1980s, no dose rates were calculated that exceeded the lower DCRLs.

Births and male:female birth ratio in Scandinavia and the United Kingdom after the Windscale fire of October 1957.

The Windscale (UK) fire of 1957 carried radioactive fallout according to the then prevailing wind patterns, in a North-Easterly direction across the Nordic countries, toward Norway. The male:female ratio at birth (M/F) is known to be increased after parental exposure to ionising radiation due to foetal losses that affect female more than male pregnancies. This study was carried out in order to ascertain whether the Windscale fire had any effects on M/F and birth rates in the United Kingdom and Scandinavia. Annual live births by gender were obtained from a World Health Organization dataset. The null hypothesis was that there were no significant changes in M/F or in births in temporal association with the 1957 Windscale event in abovementioned countries. There were no significant effects on the UK and most of Scandinavia but there was a significant rise in M/F for Norway and Finland with an aggregate deficit of around 4000 births in each country. A recent study suggests that the plume from the reactor extended further east than previously believed. This study confirms that contamination from the Windscale fire had a negligible impact on the UK (as measured by birth effects) but had a significant impact on births in Norway and Sweden.

Mortality and cancer registration experience of the Sellafield workers known to have beeninvolved in the 1957 Windscale accident: 50 year follow-up

This paper studies the mortality and cancer morbidity of the 470 male workers involved intackling the 1957 Sellafield Windscale fire or its subsequent clean-up. Workers werefollowed up for 50 years to 2007, extending the follow-up of a previously published cohortstudy on the Windscale fire by 10 years. The size of the study population is small, but thecohort is of interest because of the involvement of the workers in the accident. Significantexcesses of deaths from diseases of the circulatory system (standardised mortality ratio(SMR) = 120, 95%CI = 103–138; 194 deaths) driven by ischaemic heart disease (IHD) (SMR = 133, 95%CI = 112–157, 141 deaths) were found when compared with the population of Englandand Wales but not when compared with the population of Northwest England (SMR = 105, 95%CI = 90–120and SMR = 115, 95% CI = 97–136 respectively). When compared with those workers in post at the time of the firebut not directly involved in the fire the mortality rate from IHD among thoseinvolved in tackling the fire was raised but not statistically significantly (rate ratio(RR) = 1.11, 95%CI = 0.92–1.33). A RR of 1.11 is consistent with an excess relative risk of 0.65 Sv − 1 as reported in an earlier study of non-cancer mortality in the British NuclearFuels plc cohort of which these workers are a small but significant part.There was a statistically significant difference in lung cancer mortality (RR = 2.18, 95%CI = 1.05–4.52) rates between workers who had received higher recorded external doses during thefire and those who had received lower external doses. Comparison of the mortality rates ofworkers directly involved in the accident with workers in post, but not so involved, showedno significant differences overall. On the basis of the use of a propensity score theaverage effect of involvement in the Windscale fire on all causes of death was − 2.13% (se = 3.64%,p = 0.56) thoughthis difference is not statistically significant. The average effect of involvement in the Windscale firewas − 5.53% (se = 3.81,p = 0.15) for all cancersmortality and 6.60% (se = 4.03%, p = 0.10) for IHD mortality though neither figure was statistically significant.This analysis of the mortality and cancer morbidity experience of those Sellafield workersinvolved in the 1957 Windscale fire does not reveal any measurable effect of the fire upontheir health. Although this study has low statistical power for detecting small adverseeffects, due to the relatively small number of workers, it does provide reassurance that nosignificant health effects are associated with the 1957 Windscale fire even after 50 years offollow-up.

Fifty years of hopes and fears

Atomic energy was cutting edge when the Windscale fire showed the world the effects of a nuclear accident. Fifty years on, we have more innovative ways to generate electricity. This week Walt Patterson offers what is virtually an obituary for the nuclear power industry in the United Kingdom. But 50 years on from the serious nuclear accident at Windscale, it is not the safety record that spells the end of the industry. It's pure economics. With the investment risks now transferred to private industry, small-scale gas turbine generation is the obvious choice for a quick return on capital. Nuclear power was worth a try, says Patterson, but without governments pumping the money in to sustain it, it can't pay its way.

A study of the movement of radioactive material released during the Windscale fire in October 1957 using ERA40 data

In October 1957 a fire in Pile Number 1, a nuclear reactor at the Windscale Works, Sellafield, resulted in the accidental release of radionuclides to the atmosphere. Previous studies have described the atmospheric transport of the resultant radioactive plume from its release on the Cumbrian coast of Northwest England to its passage across mainland Europe. Those past studies have suffered from uncertainties concerning the quantity and timing of emissions and meteorological conditions. Crabtree [1959. The travel and diffusion of the radioactive material emitted during the Windscale accident. Quarterly Journal of the Royal Meteorological Society 85, 362] initially produced estimates of plume transport based on weather observations and radiosonde profiles. Later, ApSimon et al. [1985. Long-range atmospheric dispersion of radioisotopes—I. The MESOS model. Atmospheric Environment 19(1), 99–111] based estimates of plume transport on trajectories calculated from weather charts. More recently, Nelson et al. [2006. A study of the movement of radioactive material discharged during the Windscale fire in October 1957. Atmospheric Environment, 40, 58–75] used a full three-dimensional dispersion model using digitised weather data from similar charts. This study aims to further reduce uncertainty in the plume's behaviour by using the latest available Numerical Weather Prediction Model reanalysis of meteorological data from the European Centre for Medium Range Weather Forecasts (ERA-40) coupled with current best estimates of the radioactive emissions profile. The results presented here generally support the findings of previous studies though an improvement in model comparisons against observational measurements has been found. The opportunity was also taken to extend the time horizon, and hence geographical coverage, of the modelled plume. It is considered that this paper presents the best estimate to date of the plume's behaviour.

A study of the movement of radioactive material discharged during the windscale fire in October 1957

In October 1957, an accident involving a fire in a nuclear reactor at Windscale Works, Sellafield, on the Cumbrian coast of England released a quantity of radioactive material into the atmosphere. Past studies have examined the resultant ground-level concentrations of radioactivity in the UK and the rest of Europe using trajectory models or the analysis of milk samples taken at the time. Presented here is the latest study into the levels of radioactivity attributed to these releases which has been undertaken using the Met Office's Nuclear Accident Model, NAME. The study examines the direction and timing of the transport, indicating the most likely spread within Europe of radioactive material from the accident. Best estimates are presented of likely time-integrated air concentrations and ground-level air concentrations of radioactivity throughout the initial few days after the accident. Although these estimates were not expected to be very accurate due to the source term being ill-defined, the results have been presented for completeness. The report concludes that NAME manages to successfully recreate the general movement of the radioactive plume and is in broad agreement with previous analyses. Discrepancies between modelled and measured plume arrival and activity for certain locations are primarily associated with errors in the calculation of the wind fields used by the model. Model predictions for this event could be improved by reducing the uncertainties in the release scenario and Met data used by NAME, and this possibility will be explored in future work.

Retrospective Search for Evidence of the 1957 Windscale Fire in NE Ireland Using 129I and Other Long-Lived Nuclides

The accident at Windscale in October 1957 resulted in the release to the atmosphere of a large quantity of radioactivity. The presented work is a retrospective search for evidence of contamination from the accident in the northeastern region of Ireland. A lake yielding a high-resolution sedimentary record was identified near the northeast coast of Ireland. This site was used to reconstruct the history of radionuclide input to the region, based on the analysis of a set of cores extracted from the lake. A chronology for sediment accumulation within the lake was established using radioisotopic dating techniques (including 270Pb). High-resolution gamma and alpha spectrometry techniques were used to quantify concentrations of 137Cs, 239,240Pu and 241Am, all of which were released during the accident. The primary radioactive component of the release was 131I (T1/2 = 8 days), but this short-lived isotope has long since decayed. However, 129I (T1/2 = 1.57 x 10(7) years) was also released during the accident, and in a known ratio to 131I. Recent advances in accelerator mass spectrometry now make it feasible to measure 129I at ultra-trace level and thereby retrospectively reconstruct 131I deposition. Clearly resolved concentration profiles for 137Cs, 239,240Pu and 241Am in the lake cores reflect known historical fallout trends. The data suggest that any contamination from the Windscale fire that might have reached this catchment has been overwritten by input from the testing of nuclear weapons in the atmosphere. A time-series for 129I in lake sediment shows that concentrations in recent sediments are approximately 10 times greater than concentrations recorded in strata corresponding to the period of maximum fallout of other radionuclides from atmospheric testing of nuclear weapons (1964). These recent increases in 129I are attributed to increased emissions from the nuclear industry. The study yields no evidence of any enhancement in radioisotope concentrations, over and above global fallout, in strata dated to 1957, and we conclude that contamination from the Windscale fire had negligible impact on the northeastern region of Ireland.

The medical effects of postulated accidental release of radioactive material from Heysham nuclear power station

The effects of a postulated reactor accident at one of the four AGRs at Heysham, NW England, have been studied, assuming a 10% release of the radioactive core. Methods used are a computer program TIRION, analysis of the radiation doses from the Chernobyl release of 1986 and the Windscale fire of 1957. Fatal cases predicted are 200 on-site, 3000 within 30 km and 250,000 in the cloud paths over Northern England. The results would suggest the incidence of fatal cancer would increase from roughly 20% to 27% in the postulated exposed population of 3.6 million.

Acid rain — pollution for export

In recent months we have all become saturated with media coverage of the happenings at Sellafield. The exploits of the Greenpeace organisation, the no-go beaches in Cumbria, the claims and counter-claims about contaminated fish in the Irish Sea and even the alleged linking of a previous Windscale fire with the birth of Down's syndrome babies are all topics on which physicists could probably contribute, in a meaningful way, to any after-dinner discussion or common room debate.