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NORM in Scrap Metal...

NORM in Scrap Metal. Richard van Sonsbeek Röntgen Technische Dienst bv Dept. Radiation Protection Services P.O. Box 10065 3004 AB Rotterdam The Netherlands Phone +31 (0)10 2088229 Fax: +31 (0)10 4158022 e-mail: r.van.sonsbeek@rtd.nl. The Dutch approach.

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NORM in Scrap Metal...

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  1. NORM in Scrap Metal... Richard van Sonsbeek Röntgen Technische Dienst bv Dept. Radiation Protection Services P.O. Box 10065 3004 AB Rotterdam The Netherlands Phone +31 (0)10 2088229 Fax: +31 (0)10 4158022 e-mail: r.van.sonsbeek@rtd.nl

  2. The Dutch approach

  3. Melting radioactive material with scrap metal • Health risk for workers and public (neighbours, users of products) • Contamination of foundries and the environment • Financial consequence for company that is held liable Especially with strong artificial sources

  4. Measures to avoid risks • Adding clauses in contracts stating that loads of scrap metal should be free of radioactive materials • Check incoming loads of scrap metal for radioactive materials: portal detectors, crane detectors, portable detectors • Same precautions are taken by the (bigger) scrap metal traders

  5. Portal detector

  6. Legal framework • Dutch Nuclear Energy act: It is prohibited to possess, use, import, export, or dispose of radioactive substances without a license; • Suspicion to be in possession of radioactive substances without a license must be reported to the relevant authorities, i.e. VROM Inspectie, the Dutch Inspectorate for the environment

  7. Radiation Protection Ordinance • Exemption, and clearance levels per radionuclide in terms of activity concentration, and total activity; • Summation rules for mixtures; • Distinction between practices (artificial sources), and work activities (sources of natural origin, i.e. NORM)

  8. Work activities • Two limits for activity concentration • One below which the radioactive substance is exempted from the regulations; • Another one, that is ten times higher, below which “only” reporting of the work activity is required;

  9. Limits for work activities

  10. Guideline for Metal Recycling Industry • First version drawn up in 1997 • After three revisions, and following the publication of the decree on radioactively contaminated scrap (January 2003), a completely new guideline has been published by VROM Inspectie.

  11. Advice in guideline Perform measurements on each incoming load of scrap with appropriate radiation detection equipment, and by sufficiently trained personnel

  12. Further investigation to be performed by the trader • background radiation level; • maximum dose rate; • extent, and shape of the radiation field; • origin, destination, transport company, weight quality, and description of the load • If dose rate > 20 Sv/h or 200 times background: report directly to VROM Inspectie, and keep at a distance.

  13. Report to VROM Inspectie • Result of the further investigation • Scrap Metal trader shall propose a Solution

  14. Two possible solutions • Return container to sender without opening it. • Have load inspected, and sorted out

  15. Returning load to sender • Only permitted if the maximum dose rate is smaller than 5 Sv/h; • No suspicion that the load contains a single concentrated source; • Declaration by sender that he will take back the load, and proof thereof; • Permission from VROM Inspectie • A Dutch sender always has to have the load inspected, and sorted

  16. Inspection, and sorting • Expert company with license (RTD) • Plan of action must be approved by VROM Inspectie

  17. Plan of Action: preparation • Radiation expert, minimum level 3 with sufficient experience • Appropriate radiation detection-, and personal protection equipment • Packing material • Shielding material (if necessary) • Transport container

  18. Plan of action: steps • Perform radiation measurements on the outside of container • Give instruction to assistants • Put on Personal Protection Equipment • Unload container in controlled way on liquid proof floor • Check every batch that is unloaded • Isolate radioactive objects

  19. Analysis of radioactive objects • Dose rate measurements • Contamination measurements • Take Samples • Take Pictures • Record marks

  20. Final actions • Pack radioactive objects or prevent radioactive material to disseminate • Store radioactive objects on location, with appropriate instruction to the customer, or • Transport radioactive objects for further analysis, or storage at RTD’s premises • Check used equipment, floor, and container for contamination

  21. Report • Details of load • Plan of Action • Involved persons • Used equipment • Dose rates measured • Contamination measured • Result of laboratory analysis • Dose to persons, and environment • Conclusion, and advice

  22. Treatment of isolated radioactive objects -1 • Return to an original sender outside the Netherlands (transport regulations, international procedures, permission from VROM Inspectie, declarations from the sender) • Re-use of the objects after decontamination by a licensed company, e.g. Reym

  23. Treatment of isolated radioactive objects -2 • Process the objects at Siempelkamp (Krefeld, Germany), if the criteria set by this company are met; • Dispose of the objects as radioactive waste directly to COVRA, the Central Organisation for Radioactive Waste in the Netherlands

  24. Number of incident reports • Portal detectors are very sensitive • Portal detectors do not distinguish between artificial radioactive sources and other radioactive material  Lot of radioactive objects are intercepted that otherwise would not have been noticed, e.g NORM contaminated objects

  25. Summary of incidents1996-2002 • 1,497 reports to VROM Inspectie, of which • 892 reports (60%) concerned loads of scrap metal • The last figure includes “false alarms” • Most inspections have been performed by radiation experts of RTD

  26. Trends • Number of reports on loads of scrap metal increased almost monotonously from 39 in 1996 to 208 in 2002, and is still increasing;

  27. Maximum dose received by radiation expert • Average effective dose roughly estimated to be maximum 25 Sv per job (10 Sv due to external irradiation, and 15 Sv due to internal contamination) • Total dose received by radiation expert < 0,25 mSv/year (also due to other radiological work)

  28. NORM in scrap metal • In 2001, and 2002, about 70% of the reports on loads of scrap metal, concerned NORM contaminated objects; • About 25% to 35% of these reports concerned objects containing radioactive slag-wool

  29. Contaminated beer barrels

  30. Information on beer barrels • Load originated from Turkey; • 28 contaminated barrels between other contaminated objects; • max. dose rate on surface of barrel: 6.5 Sv/h; • It was decided to make an x-ray before opening one of the Barrels

  31. X-ray of one beer barrel

  32. Content beer barrel

  33. Results • Cans contained Ra-226 scale with an activity concentration of 131 Bq/g; • Wilful action to illegally dispose of radioactive material and / or harm a competitor; • The barrels were processed at Siempelkamp

  34. Conclusion -1 • In the Netherlands a method has been developed in which loads of scrap metal are inspected, and sorted out safely; • Radiation dose received by workers, and general public due to radioactively contaminated loads has been very limited;

  35. Conclusion -2 • The chance that radioactively contaminated scrap metal is intercepted has become higher: • More portal detectors (at the end of 2002 at least 66 companies have installed one or more) • Introduction of crane detectors

  36. Decree on radioactively contaminated scrap • Obligation to perform measurements, and keep registry of these measurements; • Obligation to train personnel

  37. Test protocol Portal detectors • In a separate regulation the minimum requirements for radiation detection equipment are stated. • RTD performed inter-comparison measurements on 32 portal detectors • All, or almost all fulfil the requirements for sensitivity, i.e. to be able to detect a Co-60 source that causes a dose rate of 20 nSv/h

  38. Training of personnel • Currently the training provided by RTD is the only one that is acknowledged by the Dutch authorities • Up to an including April 2004, about 100 employees of scrap metal traders followed our one day course on radiation protection

  39. That’s all folks!!!

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