Application of the International Safety Standards to Radon and NORM Denis Wymer, IAEA Shengli Niu, ILO

International Safety Standards Promoting international harmonization of radiation protection and safety IAEA Statute – establish Safety Standards and provide for their application In consultation/collaboration with competent organs of the UN and the specialized agencies concerned (e.g. ILO, WHO, FAO etc.) International consensus

International Safety Standards Safety Fundamentals Safety Requirements Safety Guides

Safety Guides: Occupational exposure to Rn & NORM

Documents supporting the Standards – Safety Reports

Other Safety Reports in preparation General: “Assessing the need for radiation protection measures in work involving minerals and raw materials” Practice-specific: Phosphates Zircon TiO2 Industrial uses of thorium Monazite and rare earths Production of metals Coal & coal ash Aim to publish in 2006

IAEA Safety Glossary – definition of “NORM” “Radioactive material containing no significant amounts of radionuclides other than naturally occurring radionuclides” Radioactive material = material designated in national law or by a regulatory body as being subject to regulatory control because of its radioactivity Note: TENORM is not in the Safety Glossary and its use is discouraged: It does not serve any useful purpose for radiation protection -- some material in its natural state is more radiologically hazardous than some “technologically enhanced” material The real issue is whether the material is classified as radioactive (i.e. whether it needs to be controlled)

Application of the Standards – (1) Radon Normally considered as chronic exposure subject to intervention Optimization of protection -- optimized action level for intervention through remedial action Guideline action level 1000 Bq/m3 for workplaces No action required below action level If remedial action cannot reasonably achieve reduction to below action level, apply requirements for practices (usually an issue only in underground workplaces)

Application of the standards – (2) NORM As with radon – optimization of protection Usually unnecessary to regulate material below: 1 Bq/g (U, Th series radionuclides) 10 Bq/g (K-40) irrespective of quantity, or whether natural or processed Building materials below these levels may require consideration – separate guidance being developed Does not apply to Rn in air, drinking water, foodstuffs, residues in environment, transport Can also be used as clearance levels

What happens if the levels for Rn (after attempted remediation) and/or NORM are exceeded? Again – optimization of protection Graded approach to regulation Consider existing OHS and environmental controls Then select appropriate regulatory approach Decide not to apply regulatory requirements (for instance, by exempting the practice or source) Notification alone Notification + registration Notification + licensing

(1). Guideline criteria for deciding not to apply (1) Guideline criteria for deciding not to apply requirements (gamma and dust) Guideline level for occupational exposure – 1 to 2 mSv/a (Safety Guide RS-G-1.1, based on ICRP 75) Safety Guide RS-G-1.7: materials for which regulation is usually unnecessary on the basis of activity concentration are unlikely to give rise to worker or public doses >1 mSv/a Experience (see, for instance, UNSCEAR 2000): doses to public << doses to workers, especially if wastes subject to normal industrial controls Therefore, we can use occupational guideline level of 1-2 mSv/a, in the knowledge that, below this level, doses to public will be <<1 mSv/a

(2) Guideline criteria for “notification alone” International Basic Safety Standards (BSS) – notification alone could be sufficient where exposures are unlikely to exceed a small fraction of the relevant limits Useful where regulatory body simply needs to be kept informed

(3) Guideline criteria for “notification + registration” Appropriate for many types of activity involving exposure to radon and/or NORM Most of such operations by their nature cannot give rise to extreme exposure scenarios Some OHS and environmental controls already likely to be in place Minimal additional requirements may be needed for radiological purposes, e.g. monitoring, good work practices – basic ALARA considerations

(4) Guideline criteria for “notification + licensing” The highest level in the graded approach Appropriate only where specific measures needed to control the actions of workers, formalized procedures to keep within dose limits and maintain doses ALARA Likely to be needed only in certain operations, e.g. involving significant quantities of material with very high activity concentrations

Future development of the Standards The BSS are now nearly 10 years old At the time of publication of the BSS, explicit ICRP recommendations on natural sources existed only for radon Additional standards material has since been included in various Safety Guides BSS now starting to be reviewed

Review of standards: Issues for natural sources Possible need for some clarification and consolidation, but otherwise relatively few issues have been raised Some gaps, e.g. cosmic radiation, building materials Existing exemption levels are based on doses of the order of 10 μSv/a – not applicable to NORM The radon action level does not apply to uranium mining, but uranium ore is just one type of NORM – why should we have different standards for the nuclear fuel cycle?

The standards are in place The standards are in place. So …… what are the implications for industrial processes? Activity concentrations and doses: Facility-specific measured data are becoming more plentiful Many previously-modelled worker doses are gross overestimates IAEA Safety Reports will include new, previously unpublished data based on facility-specific measurements and dosimetry The list of materials >1 Bq/g (U, Th series) is not that large (44) The list of processes giving rise to worker doses from gamma and dust >1-2 mSv/a, or to Rn >1000 Bq/m3, is even smaller (9) Non-excluded exposures to K-rich materials can be disregarded – doses always <1 mSv/a, irrespective of K-40 concentration

Typical activity conc. (Bq/g) NORM needing regulatory consideration on the basis of activity concentration – (1) raw materials Material Typical activity conc. (Bq/g) Monazite sand 40 to 600 232Th+ Metal ores e.g. Nb/Ta, Cu Up to 10 238U+, 232Th+ Zircon sand 1 to 4 232U+ Phosphate rock 0.03 to 3.1 238U+ Feedstocks, TiO2 production 0.001 to 1.9 238U, 226Ra Bauxite 0.035 to 1.4 232Th+

Typical activity conc. (Bq/g) NORM needing regulatory consideration on the basis of activity concentration – (2) bulk residues Material Typical activity conc. (Bq/g) Niobium slag 20 to 120 232Th Tin slag 0.07 to 15 232Th Phosphogypsum, HCl process 2 to 10 226Ra Red mud, alumina production 0.1 to 3 232U, 232Th Phosphogypsum, H2SO4 process 0.015 to 2.1 226Ra Copper slag 0.4 to 2.1 226Ra Phosphorus slag 0.3 to 2 238U

Typical activity conc. (Bq/g) NORM needing regulatory consideration on the basis of activity concentration – (3) scales Material Typical activity conc. (Bq/g) Oil & gas production scale 0.1 to 15 000 226Ra Phosphoric acid wet process scale 0.003 to 4000 226Ra TiO2 pigment production scale <1 to 1600 228Ra, 226Ra Rare earth extraction scale 1000 226Ra, 228Th Scale, mines with Ra-rich water Up to 200 226Ra, 228Ra Iron smelting scale Up to 200 210Pb, 210Po Coal combustion scale >100 210Pb

Typical activity conc. (Bq/g) NORM needing regulatory consideration on the basis of activity concentration – (4) sludges, sediments Material Typical activity conc. (Bq/g) Rare earth extraction residue 23 to 3150 228Ra Oil and gas production sludge 0.05 to 800 226Ra Niobium extraction precipitate 200 228Ra Iron smelting sludge 12 to 100 210Pb TiO2 pigment production residue <1 to 15 232Th, 228Ra Water treatment sludge 0.1 to 14 226Ra

Typical activity conc. (Bq/g) NORM needing regulatory consideration on the basis of activity concentration – (5) precipitator dust Material Typical activity conc. (Bq/g) Elemental phosphorus furnace dust 1000 210Pb Fused zirconia furnace dust 600 210Po Niobium extraction furnace dust 100 to 500 210Pb, 210Po Metal smelting furnace dust Up to 200 210Pb, 210Po

Typical activity conc. (Bq/g) NORM needing regulatory consideration on the basis of activity concentration – (6) intermediate products Material Typical activity conc. (Bq/g) Thorium compounds Up to 2000 232Th Thorium concentrate Up to 800 232Th Pyrochlore concentrate 80 232Th Cerium concentrate 10 232Th Fused zirconia 2.1 to 3.9 238U

Typical activity conc. (Bq/g) NORM needing regulatory consideration on the basis of activity concentration – (7) products Material Typical activity conc. (Bq/g) Gas mantles 500 to 1000 232Th Thoriated glass 200 to 1000 232Th Th-containing polishing powders 150 232Th Thoriated welding electrodes 30 to 150 232Th Thorium alloys 46 to 70 232Th Zircon refractories 2.6 238U Phosphate fertilizers 0.4 to 2.3 238U Technical grade phosphoric acid 0.14 to 2 238U Phosphogypsum plasterboard 0.004 to 0.7 226Ra

Type of operation Worker dose (mSv/a) Types of operation identified as requiring regulation on the basis of gamma/dust worker doses >1-2 mSv/a or Rn >1000 Bq/m3 Type of operation Worker dose (mSv/a) Rare earth extraction Approaching (exceeding?) dose limit Production of thorium compounds Typically 6 to 15 Th-containing product manufacture Processing Nb/Ta ore Doses can vary from <1 up to a Some underground mines significant fraction of dose limit Scale removal, oil & gas Scale removal, TiO2 pigment prod. <1 to 6 Thermal phosphorus production 0.2 to 5 Fused zirconia production 0.25 to 3

To summarize …………… The international standards provide the necessary requirements and guidance for protection of workers against radon and NORM No major changes in standards anticipated Supporting material (Safety Reports), much of it practice-specific, is being developed in order to assist in the application of the standards (cont’d)………………..

cont’d ……………. The standards provide clear criteria for identifying what can be disregarded from a regulatory point of view – these criteria are expressed in terms of activity concentrations The standards provide for a graded approach to regulation, consistent with the optimization of protection Important to take into account existing OHS and environmental controls – these may provide sufficient protection against radiological hazards (cont’d)…………………….

cont’d…………… One option in the graded approach is a decision not to apply regulatory requirements Guideline criterion for gamma and dust exposure is a worker dose of 1-2 mSv/a – corresponding doses to the public are likely to be <<1 mSv/a Therefore, availability of reliable information on worker doses is important Studies based heavily on modelling can be misleading -- tend to overestimate worker doses (cont’d)……………………..

Possibility of doses >>1-2 mSv/a: cont’d………………… Possibility of doses >>1-2 mSv/a: Rare earths extraction Manufacture of Th compounds & Th-containing products Nb/Ta ore processing Some underground mines (Rn exposure) Some scale removal operations (e.g. oil & gas industry) Possibility of doses moderately >1-2 mSv/a: Some underground mines Some scale removal operations (e.g. TiO2 production) Fume & precipitator dust (phosphorus, ZrO2 production) This is not a very long list !

To conclude………………. The so-called “NORM problem” is not a problem We have the necessary standards – an optimized approach to defining: the scope of regulation the degree of regulation Existing OHS and environmental controls must be taken into account We know what we are up against – on the basis of international standards, the number of industrial processes requiring specific radiological controls is not that great !