Indian scientists have developed for the first time a Local Area Network (LAN) based online 'Gamma Dose' logger to continuously monitor ionising radiation in the environment around nuclear reactors and associated fuel cycle facilities.

"Such continuous monitoring also provides for early detection of excess release in case of an untoward incident and also to estimate the source term, which is essential for emergency response," Dr B Venkatraman, Associate Director, Radiological Safety and Environmental Group (RSEG) of Indira Gandhi Centre for Atomic Research (IGCAR) told PTI in Mumbai. "Our system works on batteries with solar power charging and is thus eco-friendly," he said.

Venkataraman said now real time data access through local area network and real time graphical display of dose rate values was possible. "The system sensitivity is on par with similar international systems and prompt detection of movement of any radioactive materials - both planned and inadvertent, can be detected reliably," he said.

The indigenously developed online 'Gamma Dose' logger will be at least Rs 1.5 lakh cheaper than the imported ones and also have additional features, he said. "The crux is the indigenous development of such system which means enhanced availability, less dependence on imports and more importantly easy serviceability and maintenance which means less down times," Venkataraman added. .

The Radiological Safety division (RSD) had developed indigenous gamma dose logger with capabilities of existing state-of-the-art gamma tracer with advanced features such as transmitting online data through LAN while being eco-friendly, taking into account factors such as requirement of communication towers, data security, cost effectiveness and expandability, senior scientist G Surya Prakash said in the latest IGCAR newsletter.

The system has been successfully installed at four locations --Safety Research Institute (SRI), Materials science laboratory (MSL), Engineering Services Group (ESG) and Reprocessing Development Laboratory (RDL)-- at Kalpakkam atomic establishment.

It has been working smoothly and satisfactorily for the last six months. Besides, one more monitoring location at Waste Immobilisation Plant (WIP) has been added recently, said Prakash, who developed this logger with the help of his colleagues at ICGAR.

The system essentially consists of an energy compensated Geiger-Muller tube (detector), a microcontroller with dedicated software code embedded to organise the data, the scientists said.

The measuring range of the instrument of the ionising radiation is 20-100mGy/h (milli gray per hour), they said.

For simultaneous collection of online data from several stations,the system installed at remote location is assigned an IP address and connected to the local area network to transfer the online data to a server.

Asked about the kind of commercial systems called as Gamma Tracers (off-line) which were installed and operational at Kalpakkam for more than a decade, Prakash said those are stand-alone systems with local data archival feature and data needs to be collected at the actual location.

Also, the tracer had to be brought to the laboratory for downloading the archived data.

"We are using this, still to monitor in and around the construction site of Prototype Fast Breeder Reactor and later plan to replace it by the On-line Gamma Dose Logger," he added.