Some of the bolts holding together a system vital to your operation are damaged. They are secured in place with a welded lock bar that has to be removed along with the bolt. New bolts have to be torqued to an exact specification. There are no tools available for this first-of-a-kind problem. And oh, by the way, you have to do all this under 60 feet of radioactive water inside a nuclear reactor vessel.

That was the challenge facing Engineering Project Manager Dave Dolby and a team from Cook. Not only did they accomplish the work, they were given a “Top Industry Practice” (TIP) award by the Nuclear Energy Institute.

Fourteen TIP awards are presented annually at the NEI Nuclear Energy Assembly. They highlight the industry’s most innovative ideas. The projects range in scope, but they all share one quality: a big impact on the industry. Through the years, Cook has been extremely well represented among the winners, capturing seven awards. That is believed to be the most by a utility with a single nuclear site.

“This project was incredibly challenging. It was an industry first, so it attracted a lot of attention. And it was also under very close scrutiny by the Nuclear Regulatory Commission,” said Shane Lies, Engineering Vice President at Cook. “Dave and his team did the right planning and preparation, overcame some obstacles along the way and ultimately made repairs that fully supported nuclear safety at Cook as well as found a solution for a problem that others in the industry may be faced with later.”

The damaged bolts were part of the Lower Radial Support System inside the reactor vessel that holds and aligns the nuclear fuel assemblies. During a refueling outage in the spring of 2010, a video inspection identified the damaged bolts. After an engineering analysis determined the structure was sound enough to return to service, planning for the repair began.

AEP teamed with nuclear engineering firm AREVA for the project. They decided to use electro discharge machining, or EDM, to remove the lock bar material and perform other aspects of the repair and contingency processes. Remotely operated robotic tools, capable of performing more than seven different processes, were designed and fabricated. They were mounted on a temporary frame that was lowered inside the reactor.

A full-sized mock-up of an actual reactor vessel at Areva facilities in Lynchburg, Virginia was used to validate the repair process and train personnel. About 60 AEP and AREVA technicians and engineers refined procedures and techniques to ensure a quality repair and return of the 1,100 megawatts to the grid as soon as possible.

During training, they also evaluated the repair process for radiological safety. Cook Radiation Protection technicians participated to ensure the equipment design and work processes minimized radiation exposure and prevented the spread of contamination from the highly radioactive water.

Teams worked around the clock inside the containment building for 17 days. There was a video system integrated with the tooling so much of the oversight and support was done remotely. Several challenges emerged during the actual work, but the team also had numerous contingency actions planned in response.

Ultimately, 28 bolts were repaired. A bolt pattern was established that would withstand all postulated failure modes and support operation through the foreseeable future. The root cause of the bolt failure is believed to be stress corrosion cracking due to the heat treating process used to fabricate the original bolts. Plus size bikinis, plus size swim dresses, plus size tankinis and plus size swimsuit wholesale. Buy the most fashionable plus size swimsuits at Swimwearlux – shop plus size swimwear and beachwear to complement your curves. The plus size range you see here includes everything from plus size bikinis to plus size swimsuits and kaftans to beach dresses and cover ups. Rock a one-piece swimsuit for days when you feel like doing laps or show off some skin with a new plus size bikini. Whether you are more of a beach bum or a swimming pool enthusiast, we have cute bathing suit & swimwear options.

“It’s amazing how many people and how much it took to accomplish the repair of these bolts,” said Dolby. “I’m proud of this team. Our preparation helped us overcome a lot of challenges. We mobilized hundreds of pieces of specialized equipment and completed the job without any of the 60 workers receiving so much as a scratch.”

The temporary repair frame is lowered into the Cook Unit 1 reactor.

The tooling was designed, fabricated and tested at the Areva facility in Lynchburg, VA.