Research and analysis

Merger of the BNFL, UKAEA and AWE worker epidemiology studies into NRRW

Updated 18 December 2023

Three long term epidemiological studies of radiation and other workers formerly employed by British Nuclear Fuels Ltd, by the UK Atomic Energy Authority and by the Atomic Weapon’s Establishment are planned to be merged into the National Registry for Radiation Workers (NRRW) on 1 January 2024.

At the same time, an historic archive of biological samples retained from studies of radiation workers at Sellafield that have taken place over a 25-year period up to 2010 have also been passed to the care of UKHSA by the Nuclear Decommissioning Authority. This archive is now stored in the UKHSA Culture Collections facility at Porton Down.

Background

The NRRW was set up in 1975 to enable the surveillance of the health of UK radiation workers and provide direct evidence to assess whether radiation protection regulations and guidelines provide an adequate level of protection for UK radiation workers and the public.

The study population, or cohort, was drawn from workers from a wide range of industrial employer organisations. The largest of which is the Ministry of Defence (MoD) followed by workers from sites formerly managed by British Nuclear Fuels Ltd (BNFL), workers employed by the UK atomic energy authority (UKAEA), the Atomic Weapon’s Establishment (AWE) and workers employed at UK nuclear power generation sites.

Completely separate to this study, in the 1980s BNFL, UKAEA and AWE each set up their own similar but independent epidemiological studies, which were for many years managed by these organisations. Over the years a number of scientific papers were published, based on data from these studies. However, as they contained fewer workers, the results tended to be less statistically powerful than those based on the NRRW, but they did provide employer-specific results to reassure those organisations workers.

British Nuclear Fuels Ltd (BNFL) study

This cohort consists of those employees of BNFL who were employed at the Capenhurst, Chapelcross, Sellafield and Springfields nuclear sites prior to 2003. It comprises records for about 65,000 workers of whom about 42,000 are radiation workers. No new workers were added to the cohort after BNFL was wound up by the UK government in 2004, at which time responsibility for the study passed to the Nuclear Decommissioning Authority (NDA).

UK Atomic Energy Authority (UKAEA) study

This cohort consists of workers employed by UK Atomic Energy Authority (UKAEA) and its successor organisations including Magnox and Dounreay Site Restoration Limited. In around 2010, ownership of this cohort passed from UKAEA to the NDA. It comprises over 100,000 workers of whom around 75,000 are radiation workers. New workers continued to be routinely added to the cohort until 2020.

Atomic Weapons Establishment (AWE) study

This cohort comprises of the 22,500 members of the workforce of the AWE between 1951 and 1982 of whom about 9,000 are radiation workers. The data controller for this cohort is the Ministry for Defence (MoD).

Since 2012, all 3 of these cohorts have been managed by UKHSA (and previously Public Health England (PHE)) under contract to NDA for the BNFL and UKAEA studies and MoD for the AWE study.

Justification for the merger

For a decade PHE and later UKHSA have operated these studies completely separately and independent of NRRW. However, almost all radiation workers in the BNFL, UKAEA and AWE studies are also members of the NRRW study.

It was recognised that this was an inefficient way to manage these studies and did not allow the best use of the data to provide evidence about the health risks of occupational exposure to radiation.

Therefore, UKHSA proposed to NDA and MoD that ownership of the BNFL, UKAEA and AWE studies be transferred to UKHSA, and these studies be merged into the NRRW to create a single national resource to study radiation risks.

Benefits of this merger

Increased statistical power to provide evidence about the risks of radiation exposure

1. NRRW was set up originally only with the capability to provide evidence about the risks of external radiation exposure. As such all it holds is an indicator as to whether workers were also monitored for internal contamination by radionuclides such as plutonium, uranium and tritium. However, there is now great interest in the international scientific community for gathering evidence about the possible effects of internal exposures. Each of the BNFL, UKAEA and AWE studies have information not just about whether workers were monitored for internal contamination but bioassay measurements from which internal doses can be calculated.

As a result of the merger, the expanded NRRW will have record of approximately 30,000 workers who were monitored for internal exposure and for whom internal organ doses can be calculated from the bioassay data transferred from the BNFL, UKAEA and AWE cohorts.

2. A non-radiation worker group to provide a comparison group to the radiation workers. When the health of radiation workers is compared to the general public, they are almost always found to be healthier because they are preselected (via a pre-employment medical) to be healthy – this is known as the ‘healthy worker effect’.

A comparison of the radiation workers health to that of non-radiation workers employed at the same site, and who often undergo the same enhanced level of health monitoring as the radiation workers provides a better comparison group than the general population, particularly for diseases where lifestyle factors such as smoking, alcohol consumption, obesity and hypertension that vary round the country are important factors.

The non-radiation worker components of the BNFL, UKAEA and AWE cohort will provide an idea comparison control group for the NRRW.

Note: the size non-radiation worker group is fixed and will not be added to in the future as NRRW only has a remit to collect new data on radiation workers. UKHSA has received specific ethical approval to hold this fixed control group as part of NRRW.

Reduced administrative burden

1. Cost saving in the management of the cohorts: data about a worker would only be entered into the NRRW once and not into NRRW and at least one other of these databases.

2. A reduction in time spent on information governance issues, as such issues would only need to be considered for one study (NRRW) and not all 4 studies.

3. Improved data security: the data about a worker will be held in only one database and not 4 separate databases.

Information governance issues

Prior to the transfer of control of the BNFL, UKAEA and AWE studies to UKHSA, the opinion of an NHS research ethics committee was sought to confirm that the merger was appropriate. The South Central - Oxford C Research Ethics Committee provided a ‘favourable opinion’ for the proposed merger in May 2021 (REC reference 21/SC/0063). This approval lasts 5 years and will be renewed periodically.

A new NRRW data governance group was set up to oversee the use of data for surveillance and research from the merged study. This group has representatives of UKHSA management, major employers whose workers are part of NRRW and trade union representatives. There is also a lay member of the cohort to represent the interests of members not in trade unions. See the terms of reference and minutes of the meeting of the group.

Each of the studies held a section 251 exemption under Regulation 3 or 5 of the Health Service (Control of Patient Information) Regulations 2002 to process personal data. A new application for a section 251 exemption to support the ongoing processing of personal data without informed consent in the expanded study was made to the PHE Caldicott Guardian. Approval was granted in June 2021 (to be reviewed annually).