Personnel from the US Department of Energy's Office of Environmental Management (EM) working at Idaho National Laboratory (INL) are using new technology to perform in-situ characterisation of the contents of hundreds of radioactive waste containers prior to shipment for permanent disposal.

Fluor Idaho workers testing the new technology for the EPA (Image: EM)

The in-situ object counting system (ISOCS) is being used to assess more than 320 drums, boxes and other objects at INL's Advanced Mixed Waste Treatment Project (AMWTP) that are not amenable to other non-destructive assay equipment owing to their shape or configuration. The radioisotopes in the containers' contents, which originate from multiple locations including INL and former military sites at Rocky Flats in Colorado and Mound in Idaho, must be characterised before they can be shipped for disposal at the Waste Isolation Pilot Plant (WIPP) in New Mexico.

ISOCS has been deployed by EM cleanup contractor Fluor Idaho, working with Mirion Technologies. Workers measure the dimensions of the waste containers and use a camera to map gamma rays emanating from the containers and locate portions with high levels of radiation. The system then uses this data to characterise the gamma rays and determine specific isotopes and radioactive quantities. It also double checks waste characterisation assessments for consistency.

The system has been approved by the US Environmental Protection Agency [EPA] as compliant with WIPP waste acceptance criteria.

"Putting the system into use allows us to provide the specific characterisation data required by WIPP," Fluor Idaho Manager Ed Gulbransen said. "We just had to demonstrate the ISOCS system [for EPA and EM’s Carlsbad Field Office, which is responsible for WIPP] to give them a level of confidence that we could provide accurate data each and every time the system was used on the waste containers."

Fluor Idaho is scheduled to complete waste treatment at AMWTP later this year. Waste shipments to WIPP and other offsite disposal facilities are expected to continue for a further 10 years.