New detection technology to help decommissioning

Tuesday, 11 August 2020

Raman spectroscopy works by firing lasers at a target and measuring the resulting molecular vibrations. Although a highly effective technique for identifying specific chemical compounds, it has rarely been used in nuclear decommissioning due to access constraints and high radiation fields, which can prevent the spectrometer from working at its typical effective range. The new system can still detect a weak laser signal when several metres from the target, Jacobs said.

"Standard equipment often cannot detect specific chemical agents, either because it can't get close enough or because the signals are crowded out by the overall radiation levels," Jacobs Critical Mission Solutions International Senior Vice President Clive White said. "This new type of Raman system is an important breakthrough for the nuclear industry because it provides greater certainty about the presence of hazardous materials in high radiation waste facilities, making the materials easier, cheaper and safer to detect."

The probe can be mounted onto either a remotely operated vehicle or robot arm, which enables it to be positioned within two metres of the target. It can then send a signal down an optical cable to the main Raman instrument, safely positioned tens of metres away.

Funding to take the system from proof-of-concept to commercial application has been provided by Jacobs and UK government agency Innovate UK. It is now being used to detect uranium and also substances such as kerosene and tributyl phosphate, which are used in reprocessing operations and can indicate the presence of plutonium or uranium contamination.

Legacy nuclear facilities sometimes contain significant amounts of poorly unidentified or unknown waste materials, so improved characterisation capability can reduce decommissioning costs and timescales, Jacobs said. Raman technology is also a key feature of a new integrated decommissioning system built by the company which will be demonstrated inside highly radioactive former fuel reprocessing facilities at Sellafield later this year.

This will also be a valuable tool outside the nuclear sector, in areas where human access is impossible or problematic, Jacobs said.