September-October 2017 NPJ

Reducing Dose and Saving Time with Robotic Cavity Decon By Michael Olmstead, FirstEnergy Nuclear Operating Company. Michael Olmstead Michael Olmstead is the Reactor Services Project Manager at Perry Nuclear Power Plant in Perry, Ohio. In this role, Mike is responsible for project management and integration of undervessel, refuel floor, in vessel visual inspections, hydraulic control unit refurbishment and in- service inspections. He has been in his current role since June 2015. Mike began his career with the U.S. Navy in 1999. After that he was a Senior Reactor Operator Candidate with Constellation Energy at Nine Mile Point Unit 1, Westinghouse Lead Module Field Engineer in Haiyang, China and Westinghouse Resident Site Manager at Nine Mile and Perry Nuclear Plants. Mike holds a Bachelor’s degree in Naval Architecture from the U.S. Naval Academy in Annapolis, Maryland and a Master’s degree in Engineering Management from Old Dominion University. Robotic Cavity Decontamination BWR and PWR nuclear plant operators effectively reduce personnel dose by decontaminating the surfaces of the refueling cavity, dryer and separator pools, and components within these spaces. Plant operators have employed several methods to handle this task; however, the results vary in effectiveness for meeting ALARA and decontamination coverage goals. Faced with these challenges, many nuclear utilities are constantly seeking to improve decontamination methods and tooling. For this reason, FirstEnergy Nuclear Operating Company (FENOC) approached Diakont to develop an improved underwa- ter robotic decontamination tool. Some of FENOC’s requirements included operation in parallel with other activities, having the mobility to swim/navigate throughout the refueling cavity, ad- hering to walls, floors, and curved surfaces, and reliable and ef- fective surface decon- tamination such that manual scrubbing is not required. During the Spring 2017 out- age, FENOC’s Perry Nuclear Power Plant in Ohio completed its first successful underwater decontamination using the newly developed decon tool, achieving its ALARA goals and saving time over previ- ous methods. Producing 1,268 megawatts of electricity (enough to power more than 1 million homes), the BWR-6 at the Perry site is one of the largest single-unit plants in the United States. Established Decontamination Methods Historically, nuclear plant operators conducted cleaning and decontamination of refueling cavity surfaces by one of five methods: manual scrubbing, the use of strippable coatings, high-pressure washing, hydrolasing, and automated decontamination using robotic tooling. Each of these methods can be effective, but there are advantages and disadvantages of each. Manual scrubbing is a straightforward procedure that doesn’t require expensive equipment or training, however, this method results in extensive personnel dose exposure, requires drain down, and the decontamination results can vary. The use of strippable coatings is an effective decontamination method since the coatings seal any contaminants in place, which are then stripped away. This method is costly and requires trained personnel for the application and removal of the coatings. It also produces considerable radiological waste. The strippable coating is often applied manually, resulting in relatively high dose exposure during application, and generally requires curing time thereafter, making it one of the most time-consuming decontamination methods. Nuclear Plant Journal, September-October 2017 NuclearPlantJournal.com 43 (Continued on page 44)