Oct 31 2017
Diakont's underwater robotic decontamination service was featured in the September-October issue of the Nuclear Plant Journal as a dose saving, more efficient solution.
Diakont used the robotic decon solution to clean and decontaminate the refueling cavity, dryer and separator pools for a North American nuclear power plant. Historically, nuclear plant operators have conducted cleaning and decontamination of these surfaces manually, after draining water from the space. However manual decon is slow, and can result in excessive personnel dose exposure. Diakont's underwater robotic decon services present a vast improvement over manual decon because it reduces personnel dose exposure, reduces radwaste, doesn't impact plant chemistry, and doesn't risk inadvertently spreading contamination. Also Diakont's decon method avoids the risk of personnel injury and component damage associated with hydrolasing. And by performing the decon robotically while the cavities are flooded, in many cases the critical path outage schedule can be shortened.
Able to decontaminate horizontal, vertical, and curved surfaces, Diakont's tools easily navigate to areas within flooded cavities that are inaccessible to previous solutions, performing decon in parallel to other activities including fuel movement. Also, unlike other legacy solutions, the Diakont tools do not require continuous use of an overhead crane or other method of suspension while performing the decon activities.
The ROV-type decontamination tool attaches and drives along the cavity and component surfaces using a high-force, no-flow vortex generator, even in the presence of Residual Heat Removal (RHR) or shutdown cooling flow. Efficient, effective cleaning is performed using a rugged brushing action to detach the crud, while vacuuming it away at high flow rates to a submerged filter.
During the refueling outage, Diakont's decontamination services were so effective that no additional manual cavity decon was required after drain-down. Using the tool's ability to swim, attach, and crawl, Diakont decontaminated the majority of the surfaces designated by the plant operator. Preliminary surveys indicated that all contamination levels were reduced to <50K dpm/100 cm2, helping the utility meet their INPO/Industry collective radiation exposure goals.
Applications
Diakont cleaning and decontamination services are ideal for servicing various underwater areas within nuclear power plants:
"Diakont's remote decontamination service helped the plant operator meet the INPO/Industry collective radiation exposure goals," says Jacco Goemans, Director of Nuclear Solutions for Diakont. "Diakont's decontamination system provides crucial decontamination services in a safer, more efficient manner."