May-June 2019 NPJ

NuclearPlantJournal.com 43 Nuclear Plant Journal, May-June 2019 EPRI Quick Guides Make Condition- Based Maintenance Easier By Michael Taylor, Electric Power Research Institute. Michael Taylor Michael Taylor is a Principal Technical Leader for EPRI’s Nuclear Sector Integrated Monitoring and Diagnostics. His experience in nuclear and fossil generation, data analytics, and plant diagnostics allows him to provide insight as an end-user during development phases of research projects. Michael leads the Condition- Based Maintenance and Monitoring & Diagnostics aspects of EPRI’s Plant Modernization initiative. Prior to joining EPRI in 2016, Michael held several positions at Luminant’s Power Optimization Center and he was a Senior Reactor Operator at Exelon’s Dresden Nuclear Power Plant. Michael holds a Master of Business Administration and a Master of Science in Information Technology and Management from the University of Texas at Dallas. Plant modernization can equip nuclear plants with updated technologies and improved processes to deliver greater economic efficiency and reliability. The Electric Power Research Institute (EPRI) is leading and coordinating a global industry effort for implementing new processes and value-adding technologies in plants. Among the first modernization opportunities we saw early on and rolled out in the past 15 years was conditioned- based maintenance (CBM). CBM is simply a maintenance strategy whereby preventive maintenance is based on the condition of the equipment, not a date on the calendar. CBM is not a new concept, but implementing a CBM strategy is new to the nuclear industry. To ensure continued safety and reliability, the industry has been risk-averse in its approaches to engineering and maintenance. Transitioning to a 100-percent CBM strategy can be a daunting task. However, EPRI research has hown that properly mplementing a CBM rogram can maintain afety and reliability nd potentially cut osts. The key to mplementing a CBM trategy is data – a lot of eal-time data for each iece of equipment eing monitored that rovides information n its health. To get his data, sensors must be installed on he equipment. Plant perators need to determine: what sensors do they need, where do they need to be located and what will the benefit be from each of them. To support nuclear staff in answering those questions, EPRI developed Continuous On- Line Monitoring (COLM) Quick Guides. The Quick Guides are built on a solid technical basis and spell out exactly which sensors are required. They provide monitoring methods, and match them with the preventive maintenance (PM) tasks that can be eliminated or extended – without increasing risk – so implementation is easy. The COLM Quick Guides are component specific but not application specific, which means they are applicable in nuclear, fossil, or renewable electricity generation, petro-chem, manufacturing, or any other number of industries. The Technical Basis With traditional PM, manual inspections are performed with degradation mechanisms and failure modes in mind. Consumables are replaced based on some periodicity. Other components are inspected for unusual wear, cracking, corrosion, or any multitude of mechanisms and modes. Traditional PM sensors and measuring equipment – human eyes and hands – are manually deployed. The Quick Guides use different sensors and measuring equipment. Implementing CBM is almost as simple as replacing one sensing technology – what you did by eye and hand – for another – automated, digital sensors and measurement methods. Each Quick Guide starts with EPRI’s Preventive Maintenance Basis Database (PMBD). For each piece of equipment, the PMBD contains information on potential failure locations. It provides the engineer with the information needed to select proper PM tasks to detect the various degradation mechanisms and failure modes, the severity of each, PM task effectiveness, and average repair time. From there, each and every degradation mechanism is evaluated for a sensor or sensors that would detect the anomaly, and a detectability rating is assigned to each. Once sensors and detectability are assigned to each degradation mechanism, the same process is followed for each failure mode. The list is then compiled through an EPRI proprietary algorithm and one of three final determinations is made:  Replace the PM Task with Continuous On-Line Monitoring.  Extend the PM Task Interval Coupled with Continuous On-Line Monitoring.  No Change Recommended. EPRI developed a meticulous 4-step review process for the Quick Guides that includes utilities and component experts. The reviews ensure the algorithm outcomes make sense, the sensors can provide the needed information to substitute for a manual PM task, s i p s a c i s r p b p o t t o (Continued on page 44)