geneva, switzerland5-7 april, 2004 monitoring of radioactively contaminated scrap metal in latvia...

Geneva, Switzerland5-7 April, 2004

Monitoring of radioactively contaminated scrap metal in Latvia

A.Dreimanis (Radiation Safety Centre, Latvia)


Procedure on bulk purchase & realization of ferrous and non-ferrous metal cuttings and scrap (Cabinet Regulation No.757)

Article 32: The company engaged in a bulk purchase of ferrous and non-ferrous cuttings and scrap, ensures tests of radioactivity of these materials using:

- fixed contamination meters if the annual total purchase amount > 100 000 t,

- portable contamination meters for each load of such materials being delivered for further realization, if the annual total purchase amount < 100 000 t.


Procedure on bulk purchase & realization of ferrous and non-ferrous metal cuttings and scrap (Cabinet Regulation No.757)

- the companies engaged in bulk purchase of such items, tests them in order to prevent import in Latvia of radioactively contaminated scrap metal and radioactive waste (RW),

when exporting scrap metal, the company joins to the attendant documentation a statement testifying the load to be exported is not contaminated in a level leading to overflow of dose limits and doesn’t contain RW,


Procedure on bulk purchase & realization of ferrous and non-ferrous metal cuttings and scrap (Cabinet Regulations, No.757)

Companies performing radioactivity level testing of these materials, are responsible for:

• Observance of Regulations of running and maintenance of contamination meters,

• The quality and precision of performed contamination measurements

The personnel engaged in radiological measurements shall be trained and to be able

(i) to prepare detectors for measurements (ii) to test radioactivity level of the load, to process the

results and draw up a deed.A scrap company may sign a contract with a licensed

company for monitoring services


Cab.Regulation N 129 on Requirements for Operations with RW and Related Materials

Nuclide H-3 C-14

Fe-55 Co-60

Ni-63 Nb-94

Spec.act-ty of Fe-containing scrap (Bq/g)

1000 80 3000 0,6 3E+05 0,4

Spec. act-ty of Al-contain.scrap (Bq/g)

20000 600 70000 1 1E+05 0,6


Supervision of scrap monitoring

Supervision control on practical implementation Regulations - by Radiation Safety Centre (RDC)

1. annually checks the list of companies having valid licenses for bulk purchase & realization of scrap met.

2. has organized at university a special training course3. performs regular on-site inspections, uses mobile

gamma survey laboratory 4. gives methodological assistance+practical

instructions 5. the RDC Early Warning Sector – the National Early

warning contact point - provides the 24-hour duty and response in case of incident


Actions in case of alarms

Distinguish between nuisance and real alarms – each alarm is investigated by the use of portable monitors:

1. if the measured value with stationary device >30% of the background, the load is tested with portable unit,

2. if the portable device shows 50% above the background, a detailed inspection is accomplished,

3. repeated exceed by > 50% means radioactive contamination of scrap,

such case is reported to RDC Early warning sector


Actions in case of found sealed source

1. Detected sources are disposed by the Emergency response team by the RadWaste Management Agency (RAPA) based on request from the owner, all owners are informed on the reporting procedures to RDC and/or RAPA

2. Cases with sealed sources are reported to IAEA, as well as registered in RAPA data base for RW disposal if the load was not sent back to the state of origin,

3. The State is financing the expenses of transport of detected source/radioactive waste, other expenses are covered by the owner.


Location and sensitivity of scrap monitors

1. Stationary monitors are located at the entrance/exit of the scrap yard, portable – for screening and investigation,

2. Melting facilities routinely monitor scrap before melting and, occasionally, afterwards

Energy range of detectors– between 60 keV – 1,5 MeVMinimal gamma-sensitivity:

Stationary device – 0,1 mkSv/h, for Portable device – 0,05 mkSv/h


Service and testing of monitors

1. Monitors are annually calibrated by National Secondary standard dosimetry laboratory – the Radiation Metrology and Testing Centre

2. Functionality checks are accomplished according to instructions of monitor suppliers, sensitivity of portable monitors shall be verified daily

3. There are two special companies for monitor supply and service


Lessons and events

1. Visual inspection practices: In 2001, in a scrap yard an empty source was found; was a full incident, Response: – report to the Regulatory Body, preliminary test by radiation safety inspectors, isolation of container, delivery to RAPA disposal site.

2. In 2001, at Liepaja harbour in a scrap yard a neutron source IBN-6 (12.5 GBq), Ra-226 and Sr-90 sources (total - 2 MBq) were found

Response: - the case was managed by involving a contracted service company, the sources were disposed at the RAPA disposal site.

1. Since then no more radioactive sources have been detected in scrap metal in Latvia.

geneva, switzerland5-7 april, 2004 monitoring of radioactively contaminated scrap metal in latvia...

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