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Explore comprehensive industry case studies for effective workplace dust monitoring strategies, emphasizing air sampling techniques and ALARA implementation. Conclusions from studies highlight the importance of monitoring techniques and exposure categorisation.
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Peter Shaw, HPA-RPD, UK SMOPIE - Work packages 2 and 3Industry case studies and workplace categorisation
Industry Characteristics • Large scale processes • Dusty (in parts) • Many process steps • mechanical plant • manual tasks • multi-tasking • All have workplace/individual monitoring • all do air sampling (personal and/or static)
Air sampling • Personal air sampling (PAS) • for dose estimates - UK1, UK2 and N1 (and F1) • shift and task sampling • radiometric and gravimetric • Static air sampling (SAS) • for dose estimates - F1 and N2 • reassurance monitoring and particle size (N1) • radiometric and gravimetric • Real-time dust sampling (RTDM) • SMOPIE surveys (not dose assessment) • gravimetric and optical (particle counting)
Results and conclusions from different case studies • Each case study is different • Annex 2 to Main Report • A lot of information • strategies and methods • results • advantages and limitations • practical tips • Just a small selection in this presentation
UK1 - Zircon sand, grinding and milling • Existing dust monitoring programme for many years (PAS) • UK industrial hygiene regulations • accepted by workers • Results used to assess radiation doses • Provided limited ALARA information • dusty areas and tasks • long terms trends • More sampling recommended
UK1 - Real-time dust monitoring • Specifically for the SMOPIE project • 200 measurements in 2 days • complete “map” of workplace • day-to-day changes • short-term variations • localised dust levels • dust sources • tasks • leaking pipes/vessels • exhaust air from extractors • cleaning machine!
F1. Case Study - U concentrate conversion • Comhurex, Malvési • Different to other case studies • activity concentration much higher • radiation protection (nuclear) background rather than industrial hygiene • Extensive monitoring programme • SAS, urine and lung • Focus on first step in the process • sampling drums of U concentrates
F1. PAS campaign - sampling stage • Drum unbanding/rebanding • SAS v PAS • both produce same rankings of dusty areas • PAS doses 30-100 times higher • important factors • sampler location • time profile of dust • source of dust
F1 Case study • Improvements to filling station • hopper modified to prevent over-filling • containment installed • Effectiveness demonstrated by PAS (task) • Problems with 1 drum type (from PAS/SAS) • Real-time (optical) particle counting • showing contamination peaks • Further improvements at filling station • drum handling equipment • new (confined) rebanding station
N1. Monitoring programme • Focus on precipitator dust • Leaching tests • lung class S • PAS (on 2% of shifts) • alpha/beta counting • 3 week delay • 5 day count • 245 results from 1998-2001
N1 - PAS results • Doses categorised according to type of work • 0.1 to 2.8 mSv/y • mean = 1.2 mSv/y • Statistical uncertainties are important • worker variation is greater than task variation • varied work patterns • changing air concentrations • Only cleaners (2.8 mSv/y) and control room (0.1-0.2 mSv/y) show significant difference
Conclusions from WP2 Case StudiesCategorisation of workplaces • A strict categorisation is not helpful • Instead focus on characteristics common to ALL case studies • multiple dust sources, from machinery and workers • airborne dust is always present • dust levels always varying with space and time • working patterns are complex and often change
Conclusions from WP2 Case StudiesMonitoring strategies • To implement ALARA • assessment of internal dose, and • information on how/where doses arise • requires a combination of monitoring techniques • Air sampling is better than other methods • dose assessment and ALARA information • Sampling uncertainties • are significant • are not considered enough in practice
Conclusions from WP2 Case StudiesMonitoring strategies • PAS • provides best estimate of worker doses • SAS • to check doses are low (reassurance) • underestimates, always compare with PAS • Real-time • not for dose assessment • only suitable in certain workplaces • can provide best ALARA information
SMOPIE - WP3Categorisation of exposure situations • Case studies indicated that categorisation was not helpful • Same conclusions apply in all cases • Some other factors to consider • gravimetric analysis requires constant Bq/g • alpha/beta counting requires contant radionuclide ratios • Bq/g and dose coefficent influence choice of analysis method (sensitivity)