NUVIA | ADVERTORIAL FEATURE


this information is used to generate a unique calibration for the package under investigation. At the end of a short count time (5-15 minutes) a spreadsheet of results is automatically generated, with the fingerprint factored in and the material category determined. Production of this real-time data enables timely decisions to be made and materials to be transported out of the working area for reuse and/or disposal.


Screening technologies Conveyor-mounted gamma monitors have for many years been successfully used in the coal industry for on-line monitoring of the ash content of coal loads. The technique utilises combined natural gross gamma radiation and on- line mass measurements to provide an estimate of the ash content of raw mined coal. Nuvia have deployed a similar system, the Conveyor Active Particle System (CAPS) which utilises a caesium iodide (CsI) detector, mounted under a conveyor belt and connected to an electronic control box. The 150x75mm CsI crystal and photomultiplier are housed in a compact casing and installed on the underside of the conveyor, with the long axis of the crystal orientated to line up with the centre line of the conveyor belt. The system is designed to alarm when the count per second (cps) rate, detected by the sensor, exceeds a set alarm level. The cps rate may be smoothed over a number of seconds thereby providing the average cps. On top of the electronic enclosure is mounted a combined red flashing beacon and audible alarm. When an alarm condition is detected, both are activated. The alarm may be muted at any time, but the alarm beacon will only reset when the alarm condition is no longer present.


In the event of an alarm caused by the average cps rising above the alarm trip level, the sounder and the flashing light are activated, and the highest counts value, date and time of the alarm are stored in a temporary buffer. When the alarm is reset, information in the temporary buffer is written to an alarm log file, held in the battery-backed RAM of the processor. The alarm log file holds the last 600 alarms, and data may be downloaded from the control box to a laptop.


Continued development Nuvia has built and deployed a suite of monitoring equipment to support operational, decommissioning and remediation projects, both in the nuclear and NORM generating industries. The technologies are subject to continued development to keep pace with the requirements of customers and changes in UK legislation for the management of wastes. In addition, flexibility in the deployment of the equipment is required to accommodate a wide variety of scenarios.


Applications / Projects ● Gamma depth profiles – gross gamma and spectral ● Drain surveys using a sodium iodide detector ● Tank survey using a sodium iodide detector mounted on an ROV


● Combined Groundhog and HRGS surveys to support delicensing


● HRGS of rooms for clearance ● Conveyor belt detector installed at the Olympic Park ● BEPO dose-rate survey of fuel and cooling channels ● Waste storage vault, Aktau BN-350 reactor Kazakhstan ■


Above: 1m3


bags Assayed and processed by NUVIA’s monitoring instruments at LETP, Harwell


CASE STUDY: LETP (Liquid Effluent Treatment Plant) Remediation, Harwell


CLIENT — MAGNOX ● Complete land remediation and characterisation of radiologically contaminated land at the site of a former LETP and restoration of the land to green field condition


● Excavating, Assaying and Processing 555 x 1m3 ● To date, over 60,000 x 1m3


Waste Bags per week bags to be Assayed and processed in total


● Tracking system for every waste bag ● Extensive and stringent standards prescribed by the ONR and the EA (UK regulators) ■


Above: High Resolution Assay Monitor-trailer mounted system


Above: NUVIA’s Gamma Excavation Monitor (GEM) system to enable rapid screening of excavated materials


www.neimagazine.com | October 2021 | 17


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