norm in scrap metal

The R

TD

Group

NORM in Scrap Metal...

Richard van SonsbeekRöntgen 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 R

TD

Group

The Dutch approach

The R

TD

Group

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

The R

TD

Group

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

The R

TD

Group

Portal detector

The R

TD

Group

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

The R

TD

Group

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)

The R

TD

Group

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;

The R

TD

Group

Limits for work activities

Activity concentration(Bq/g)

Radionuclidea

limit forreporting

limit forlicense

Activity (Bq)

Pb-210+ 110+2 110+3 110+4

Ra-226+ 1 110+1 110+4

Ra-228+ 1 110+1 110+5

Th-228+ 1 110+1 110+4

Th-232sec 1 110+1 110+3

U-238sec 1 110+1 110+3

The R

TD

Group

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.

The R

TD

Group

Advice in guideline

Perform measurements on each incoming load of scrap with appropriate radiation detection equipment, and by sufficiently trained personnel

The R

TD

Group

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.

The R

TD

Group

Report to VROM Inspectie

Result of the further investigation Scrap Metal trader shall propose a

Solution

The R

TD

Group

Two possible solutions

Return container to sender without opening it.

Have load inspected, and sorted out

The R

TD

Group

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

The R

TD

Group

Inspection, and sorting

Expert company with license (RTD) Plan of action must be approved by

VROM Inspectie

The R

TD

Group

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

The R

TD

Group

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

The R

TD

Group

Analysis of radioactive objects

Dose rate measurements Contamination measurements Take Samples Take Pictures Record marks

The R

TD

Group

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

The R

TD

Group

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

The R

TD

Group

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

The R

TD

Group

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

The R

TD

Group

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

The R

TD

Group

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

The R

TD

Group

Trends

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

The R

TD

Group

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)

The R

TD

Group

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

The R

TD

Group

Contaminated beer barrels

The R

TD

Group

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

The R

TD

Group

X-ray of one beer barrel

The R

TD

Group

Content beer barrel

The R

TD

Group

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

The R

TD

Group

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;

The R

TD

Group

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

The R

TD

Group

Decree on radioactively contaminated scrap

Obligation to perform measurements, and keep registry of these measurements;

Obligation to train personnel

The R

TD

Group

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

The R

TD

Group

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

The R

TD

Group

That’s all folks!!!