External Gamma Dose Rates - Temporal and Spatial Studies
Project: Sellafield external gamma dose rate surveys
Customer: Sellafield Ltd
The Challenge
Westlakes Scientific Consuling has the capability to perform external gamma dose rate surveys. For this project we were coimissioned to investigate the temporal and spatial variation of external gamma dose rates along the Cumbrian coastline. This information was used in conjunction with radionuclide content and particle size distribution of the sediments to improve model predictions relating to external gamma dose rates. The objectve was to determine a more realistic dose assessment of the coastline.
Methodologies and Approach
- Survey of Cumbrian coast with portable detectors.
- Variety of coastal substrates investigated – sand, mud, mussel beds, Sabellaria coral reef
- gamma-ray response determined especially for 60Co, 137Cs and 40K
Techniques, Expertise, Equipment Used:
- Mini Instruments type 6-81 survey meters
- MC71 energy-compensated GM tubes
- Malvern Instrument MS17
- High Purity Germanium Detector
- NaI (Tl) gamma-ray detector
- gamma-ray spectrometry
Results of work
- Issue of contract report
- Peer-review publication in the Journal of Radiological Protection:
McDonald, P., Bryan, S. E., Hunt, G. J., Baldwin, M. and Parker T. P. (2005). Field and model investigations of external gamma dose rates along the Cumbrian coast, NW England. J. Radiol. Prot. 25, pp. 67 - 82.
Benefit to customer
- Improved the performance of the model regarding the prediction of external gamma dose rates to the critical group.
- Added more reality than conservatism to the predictions.