Residues Management
Residues/Waste Management  

The best option for managing residues or waste is their minimization, what first of all requires critical analysis of relevant processes and could also involve recycling or re-use.

However, if all possibilities for minimization are exhausted, through certain operational processes or decommissioning activities NORM waste still can (unintentionally) accumulate. Regulators might require well-planned corresponding measures as precondition for issuing operation permits. Moreover, a good NORM waste management helps to operate efficiently and avoids related liability risks.

Managing NORM waste requires a well-considered sequence of safe processing due to their potential hazardousness as well as full compliance with regulatory requirements, waste acceptance criteria etc.:

1. Radiological characterization (and analysis of operational processes),
2. Treatment (also called pre-disposal and including conditioning) and subsequent
3. Disposal (i.e. long-term safe containment/storage).

In all these steps GeoEnergy Consult supports affected projects to handle NORM waste compliant and safely, process NORM waste (if necessary) efficiently as well as prevent from adverse scenarios like purposeless on-site accumulation. 

Important objectives of waste treatment are volume reduction and foremost fixation/immobilisation of radionuclides to prevent from spreading. For various waste types different treatment options apply:

Suitability of treatment options for different NORM waste types.

Conventionally, processing of uranium ore (or other NORM bearing ore) results in large amounts of tailings, which can still contain radionuclides in remarkable amount. Radionuclide Extraction from tailings resulting from high-grade ore was conceptualized to encounter the hazards of usual deposition in surface impoundments.

Purification (link to partner website) employs technologies which treat liquid waste, i.e. clean from radionuclides and other contaminants. Often wastewater is purified by (e.g. membrane) filtration, ion exchange and/or dosing of chemical reagents. Due to high energy consumption (and potentially high wastewater volumes) we do not regard evaporation technology as efficient.

By contrast, when basically solid NORM waste like sludges need to be dewatered dehydration techniques are applied. These can range from simple settling and decantation, over centrifugation or filtration until enhanced desiccation (e.g. in-drum-drying). In case of high volumes and high contamination above mentioned radionuclide extraction approach can also be a solution.

Combustible waste is usually incinerated with the main aim of drastic volume reduction. Fine-tuned emission processing ensures that radionuclides are safely kept back.

Actually decontamination is a kind of pre-treatment, which prepares NORM waste for subsequent treatment, if necessary. In general, decontamination separates the radionuclides from other residues, which can become available for easier conventional disposal.

High-force compaction, performed by encapsulated hydraulic presses often achieving a pressure equivalent to 2,000 tons, also leads to a dramatic volume reduction of suitable waste types. However, it is restricted to compactable waste types or even to spent IEX resins from processing.

Cementation is the worldwide proven standard for safe fixation/immobilization of suitable radioactive waste, though volume and weight are increased. Contaminated inorganic solutions (e.g. waste water) can be used as tempering water. Anyway, usual activity levels of NORM waste seldomly require cementation.

For radionuclide separation from bulk material like contaminated soil Remediation technologies can be indicated, e.g. soil washing or separation through radiation scanning conveyor belt technology.

Often packing of NORM waste in big bags is sufficient. To further enhance achieved immobilisation/confinement waste treatment can be finalized by packing in e.g. steel drums and/or containers. Furthermore, a waste accounting system (e.g. barcode) throughout
the management steps will ensure reliable tracking of every item.

If treatment is accomplished NORM waste is ready for final disposal. Often the state is assumed to be responsible for actual waste disposal, i.e. projects only deliver (treated) NORM waste to licensed disposal facilities. However, e.g. in case of high waste volume it can be justified that projects have an own onsite disposal facility. Anyway, in a technical view several disposal options are given, like

- Backfill in mined-out underground spaces or open pits
- Reinjection into original deposit (of liquid/flowable NORM waste),
- Surface/Near-Surface Disposal (e.g. landfill-like repository)
- Borehole disposal (if above options cannot be realized)
- Underground Disposal (e.g. co-disposal of NORM with radioactive waste).

Which option will be realized depends both on technical/radiological properties and on country-specific regulatory requirements. 

If waste comprises long-lived radionuclides of increased amount/concentration, the IAEA recommends underground disposal. However, often countries might accept surface disposal of eligible NORM waste.

In the end the duration disposal is necessary mainly depends on radiological criteria like concentration, half-life and activity of contained radionuclides as well as on country-specific requirements. By consequence, safe containment can be required over a range of hundreds to hundredthousands of years.

If you have any specific question, feel free to contact us.
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