ADVERTORIAL FEATURE | NUVIA
Supporting waste characterisation
Nuvia offers a full range of services for both the characterisation and remediation of land, and characterisation of waste materials. Services have been provided for over 16 years giving us a wide range of experience and solutions
NUVIA HAS GAINED CONSIDERABLE EXPERTISE and experience working in the field of nuclear-based decommissioning over many years both in the United Kingdom and abroad. This capability has been strengthened by development in-house of a range of assay systems to support decommissioning and land remediation initiatives both within the nuclear sector and industries generating enhanced levels of naturally occurring radioactive material (NORM). Management of resulting wastes is focused on reuse and recycle. The least favoured option is disposal as this can be a costly process and occupies a finite resource. In the past, disposal of wastes to the UK Low Level Waste Repository (LLWR) have required minimal characterisation and frequently materials were consigned by default, hence needlessly occupying space. A change in emphasis at LLWR has now driven the requirement to fully characterise materials to minimise waste going to the national repository, and make use of other disposal facilities that have opened to accept the lower end of the LLW activity range.
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Gamma-based surface mapping Groundhog’s range of radiation monitoring tools and services encompass all gamma-emitting contamination possible to be detected in the field. Using portable or vehicle mounted detectors, Groundhog
provides a high density of survey measurements, automatically records all data, uses GIS to aid analysis and is suitable for areas of all sizes. With a range of options available, particles of radioactive
material the size of a grain of sand or smaller can be detected, with survey results used to support remediation strategies based on in-situ selective sentencing of waste.
Bulk monitoring technologies Technologies used to assay materials need to be capable of measuring to very low levels of radioactivity in accordance with UK legislation. In addition, techniques used to assess bulk materials must be capable of giving accurate results, which, if challenged by the regulator, or other stakeholders, are defensible, and fully traceable back to national standards. Furthermore, contractors are required to keep to tight deadlines as the costs associated with remediation are high; assay technologies therefore need to be rapid so that downtime is minimal. Nuvia has developed a range of gamma based systems
for monitoring wastes. The High Resolution Assay Monitor (HiRAM), Gamma Excavation Monitor (GEM) and the new Information Management System (IMS) to track waste and support transport off site are three tools to support and
16 | October 2021 |
www.neimagazine.com
enhance bulk monitoring systems. The GEM System is fitted with a low resolution gamma spectrometer which is used to measure activity in mechanical excavator buckets and is capable of real-time assay of excavated materials during clearance works. The measured results can then be related to a radionuclide fingerprint, i.e. radionuclide ratios for a particular operational area, to determine the specific activity (Bq/g) of the material, which may be soil, concrete, brick etc. The presence of the bucket, placed over the GEM, triggers the proximity switch to initiate the counting routine. At the end of the count time (typically 10 seconds), a coloured light is illuminated to indicate the determined material category. At all times the display lights can be seen by the mechanical digger operator, and the data for each bucket load is automatically stored, and can be downloaded onto a laptop. The system, therefore, eliminates the need for operatives to be near the moving bucket thereby improving the safety aspects of the process and increasing throughput. The HiRAM comprises a cabin and turntable mounted
on a trailer. High Resolution Gamma Spectrometry (HRGS) equipment is installed in the cabin, which is powered at 110 volts by a petrol-fuelled generator, or can be run from a mains supply using a step-down transformer. The turntable is operated from inside the cabin, which is equipped with lighting, heating and storage space for safety documents, user manuals and maintenance records. The Information Management System (IMS) helps to speed up the data handling process, improve quality controls and reduce transcription errors. To track waste bags and manage the data, Nuvia designed and developed the IMS, comprising a database and associated software. Bags generated in remediation zones have barcode labels applied, and upon receipt into the waste assay facility, tablet devices, with barcode reader technology, are used to scan and log the bags into the database. The tablets are also used to interrogate the IMS, enabling the operators to locate bags and confirm their status. HRGS offers the advantage of being able to measure and quantify several individual radionuclides at the same time. Easily measureable radionuclides (eg Cs-137, Co-60, Eu-152) are used to factor in other radionuclides from a predetermined fingerprint. Packaged materials (eg 200-litre drums, 1m3
bags, Dolav
boxes) are rotated on the turntable, which reduces the effects of heterogeneity by averaging over the complete lateral surface of the package. The HRGS system is fully automated so that the operator simply keys in, when prompted on the laptop, physical dimensions such as waste package weight, fill height and material composition, and
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