Environmental Studies

I first became heavily involved in studies of radioactivity in the environment in 1996 when the recently-formed Magnox Electric had a need to establish its liabilities for contaminated land on a much firmer basis. Prior to then, I had looked at contaminated land studies as a potentially useful field of work although my involvement was fairly low-key and restricted to managing a small number of very localised characterisation studies where contamination was known or expected.

I was largely responsible for the development of the first version of “LARCh”, the Large Area Radiological Characterisation equipment. This comprised a high-resolution gamma ray spectrometer, coupled via software to an accurate GPS receiver or an ATS (automatic total station, which tracked position using a laser). LARCh was first deployed on 6 January 1997, at which time it was rather crudely assembled on the back of a tea-trolley pushed by a student. It first worked on 8 January 1997 (there were time pressures...) Later versions were mounted on a small, four-wheel drive vehicle or could be used man-portable.

LARCh was developed under my leadership for many years, and was deployed on all of the Magnox sites as well as several other civil nuclear sites. LARCh was well-suited for searching for diffuse contamination, and could detect man-made gamma radiation at levels suitable for demonstrating trivial risk (i.e. < 1E-6 annual risk of fatality to an individual) in a short period. It was less suitable for looking for discrete particulate contamination, although I have some ideas up my sleeve for improving its sensitivity to individual particles by approaching an order of magnitude.

I managed development and deployment of several other measurement methodologies: BIRCh, the Below Ground Investigation of Radiological Contamination (BIRCH) equipment was used for investigating drains, and with minor modification could be used in boreholes. BIRCH used a low-resolution spectrometer to survey drains, with the results being quantified as activity within the pipe bore. For freshly-drilled boreholes, the preferred method was to use high resolution spectrometry of retrieved cores, which interrogated a similar volume of material to an in-situ measurement with much more confidence as to what was being measured. The methodology enabled roughly 4 m of core per hour to be assayed to well below 0.4 Bq g-1 Cs-137 .

Equipment was deployed for environmental studies on many sites. The largest individual project that I led was to undertake studies for characterisation of large parts of the Berkeley nuclear licensed site, to justify its delicensing. My involvement was in developing methodologies and strategies for determination of residual man-made contamination, followed by the management of deployment of technologies. In very brief summary, the project started with a desk study, which categorised buildings and areas on a range of risk levels, from known contamination to no reason to believe that any contamination was likely. A variety of different techniques were then proposed to the customer, including sampling on-and off-site (to determine the normal regional background of bomb-test and Chernobyl contamination), high resolution gamma ray surveys to establish the man-made gamma ray component of the site environment down to “no danger” levels, drains surveys, dust sampling, swabbing and a comprehensive LARCh survey.

Other environmental projects which I have managed have looked at the free-release of bulk wastes, by a combination of sampling and direct measurement, underpinned where appropriate and feasible by assessment of the history of materials. I have specified measurements of environmental radon in and around landfill sites. Environmental radon is a subject which I have studied in detail and which interests me, and I would welcome opportunities to advise or work in that area.

In 1995/6 I worked as a consultant to IAEA in production of TECDOC 1017 on the Characterization of Radioactively Contaminated Land for Remediation Purposes.