Ontario Power Gen Case Study
As part of our Think Tank Friday Panel Series, the Deep Trekker team has been hosting experts from various industries to share their experiences and answer questions in live, interactive panels. On May 22, 2020 Deep Trekker was thrilled to host Think Tank Friday: Robotics for Safety and Efficiency in Energy Production.
This panel included informative discussions with energy producers, asset management teams and robotic technology experts who shared their experiences in using robotic technology for energy production and related operations. If you missed the panel live, it is available to watch on demand.
Among our group of esteemed experts was Ontario Power Generation’s Che Swearengen. Swearengen is currently a Commercial Inspection and Maintenance Diver and was able to share his experiences on the panel. Read on to discover three specific cases where Swearengen and his team benefited from the use of an ROV.
Low-visibility ROV visual inspection
The first case discussed by Swearengen was the inspection of an injection water service tank. These large underground tanks house the heavy water used for water injection. In order to meet regulatory guidelines, these tanks must be inspected consistently. Swearengen and his team made the call to use an ROV in lieu of a diver to complete the inspection.
“The benefits of using the ROV versus using an actual diver in the water are numerous,” explained Swearengen. “Number one is the radiological uptake. So there’s (a radiological) dose involved with these tanks as there are some nuclear particles in there causing radiation, but with the ROV we’re not too concerned about it getting contaminated. You can decontaminate the ROV or literally purchase another one. The other reason why we decided to use the ROV in this tank is that there was a valve that was on the bottom, it was passing water and we had no way to shut it off so to introduce a diver into that situation causes a hazard that we weren’t really looking to deal with.”
Using the ROV, Swearengen and his team were able to conduct a thorough inspection of the tank. In four hours the team had safely and accurately completed all required aspects of the inspection. Furthermore, the team was able to inspect the leaking valve as well, confirming that the valve itself was sealed.
Following the inspection, the decontamination process took place, as the ROV had been in a radioactive tank. “It (the decontamination) was very very minimal compared to if it had been a diver.”
“In this instance, costs and safety were the two driving factors. With regards to safety it was the human factor, there was no radiation and no work protection involved for shutting down the systems. Essentially we did this in a hold-op, we informed the station owners that we were going to be doing the inspection and they did not operate any pumps while we were in there. It saves quite a bit of time from trying to lock them all out and going through a lockout, tagout procedure. The other portion of that was the safety. This was a great tool to get in there and do inspection while maintaining cost and safety for everybody.”
In short, using the ROV for the inspection of the injection water tank provided benefits from a safety and cost perspective as radiation dosage was greatly minimized and no work protection needed to be enacted, while operation costs and man-hours were reduced significantly.
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The second case took place at OPG’s Pickering Unit 6. There was a known leak on a calandria however the exact location could not be determined. Housing all of the fuel bundles, the calandria is surrounded by heavy water.
The OPG team made the decision to use an ROV to locate the leak. “The driving factor here was that there was no access to actually get in and do the inspection. There was also fuel still inside the reactor core - which is the calandria - so the radiation dosage was extremely high making it unreachable for humans. We were able to actually access this with the ROV and go down around the core with the fuel bundles and get to the bottom of the tank and continue with the inspection to find the leakage area.”
The ROV saved significant amounts of money in this mission as it was unnecessary to shut the unit down, dewatering and unfuel the unit with the vehicle entering the water in lieu of human divers.
In addition to locating the leak, the team was able to seal the leakage by taking advantage of the ROV’s versatility. “We actually adapted the ROV to deliver a sealant. So while we were on top of the reactor duct with the ROV we were able to apply a sealant and seal the leakage from the inside.”
After use in the calandria, the ROV had to be decontaminated before any further use. “Over the course of a couple of months we were able to decontaminate the ROV and put it back into service.”
As with any hydroelectric facility, inspections of submerged infrastructure at Chats Falls are required to maintain safety and regulatory standards. Swearengen noted that typically these routine inspections are done by divers who look at structures such as turbines, blades and throat rings to examine for cavitation, missing metal, etc. In the past, these inspections required a 6 person dive team and expensive and time consuming lockout work protection procedures.
“We’ve adapted (the inspections) to use ROVs. It’s now a two-person crew, the work protection isn’t involved, as it's a piece of equipment and not an actual human, and we can get some pretty good results with the ROV - this is now pretty much the way we do all of our runner inspections.”
Using the ROV for inspection means that no work protection is required and a smaller crew can be used, significantly reducing both the time and money required. Furthermore, divers are kept safe and out of harm’s way. Swearengen confirmed this saying, “there are significant cost savings and it’s also safer for the people involved.”
Throughout varying missions, the use of an ROV has proven itself to be not only effective, but safe, convenient and economical for use in submerged infrastructure inspections. The versatility and durability of the vehicles allow for a variety of jobs to be completed in an efficient manner.
We sincerely thank Che Swearengen for his time and for sharing his ROV experiences with the Deep Trekker team. You can learn more about ROVs in the energy industry in our case study with Eugene Water and Electric Board and in our Using an ROV to Inspect Confined Spaces blog.