WASHINGTON, D.C.--Employees of Omaha Public Power District at Fort Calhoun nuclear energy station have been honored with the nuclear energy industry’s B. Ralph Sylvia Best of the Best Award for developing a method to accurately assess the susceptibility of stainless steel and other alloys to stress corrosion cracking.
Untreated, stress corrosion cracking can weaken piping and other components. But the onset of stress corrosion cracking has been difficult to predict given that it can take 20 years or more to develop. Through extensive research, the OPPD team determined that eddy current testing, an electromagnetic process that can detect tiny flaws in metals, can accurately measure subtle changes on the inner surface of a metal component to determine if so-called “incubation” of this phenomenon is occurring at a microscopic level and, therefore, if the onset of stress corrosion cracking is imminent.
The initial area of concern at Fort Calhoun was in the housings that enclose the control rod drives within the reactor coolant system. Some housings were unnecessarily replaced because stress corrosion cracking was suspected, but was not actually present. By creatively using eddy current testing to accurately project the start of stress corrosion cracking, the Fort Calhoun team has helped avoid the unnecessary replacement of expensive plant components, saving money and significantly reducing radiation exposure to project teams. Since its inception in 1999, the eddy current testing program has saved nearly $7 million and 10 to 50 person-rem of combined radiation exposure to workers at Fort Calhoun. The Nuclear Regulatory Commission’s limit for radiation exposure to an industry worker is five rem per year.“The team at Fort Calhoun developed a very important diagnostic tool that will improve safety and efficiency across the entire nuclear energy industry,” said Tony Pietrangelo, NEI senior vice president and chief nuclear officer. “Their ingenuity and extraordinary effort in researching this important breakthrough deserves this recognition.”The Best of the Best Top Industry Practice (TIP) award was presented at NEI’s annual meeting. The TIP awards recognize industry employees in 14 categories – four vendor awards, nine process awards for innovation to improve safety, efficiency and nuclear plant performance, and one award for vision and leadership. The Best of the Best Award honors the late B. Ralph Sylvia, an industry leader who was instrumental in starting the TIP awards in 1993. NEI this year received 134 entries for awards.Other companies with employees who received awards are: Duke Energy, Entergy Nuclear, Exelon Generation Co., Exelon Nuclear, Public Service Electric &Gas Co. (PSE&G), and Tennessee Valley Authority (TVA).
TIP VENDOR AWARDS
• TVA employees collaborated with AREVA NP to win the AREVA Vendor Award for developing a reactor vessel flange repair platform at the Browns Ferry nuclear plant in northern Alabama. The platform enabled workers to safely and efficiently repair the surfaces of the reactor pressure vessel (RPV) flange and the opposing closure head surface. TVA’s work with AREVA NP incorporated sophisticated 3-D modeling techniques to design a stable, shielded, movable work platform needed to weld and machine the surfaces.
Placed over the reactor cavity, the work platform provided shielding that reduced worker exposure by 40 percent, and it provided an air-conditioned, ergonomically favorable work environment that enhanced safety and productivity. The platform also eliminated the need to remove the RPV studs, saving at least $1 million in lost electricity generation, outage staffing and worker costs. The use of two platforms allowed multiple repairs to be performed simultaneously. This reduced the total repair time by at least 29 hours, saving $470,000 in outage staffing costs and $363,000 in lost electricity generation.
• Employees of Exelon Nuclear at Pennsylvania’s Peach Bottom power station collaborated with Global Nuclear Fuel (GNF) to earn the GE Hitachi Nuclear Energy Vendor Award for their use of the Defender Debris Filter to prevent debris from entering and potentially damaging fuel assemblies. The Defender Debris Filter, developed by GNF, captures small segments of wire, metal shavings and the like that can lead to fuel rod damage.
Exelon installed the first Defender Debris Filters in Peach Bottom 2 in 2006, after debris-related fuel damage at two reactors there. It subsequently performed the first inspection of the filters during Unit 2’s refueling outage in 2008, finding their performance excellent. To date, all of the 544 fuel assemblies with Defender Debris Filters in Peach Bottom Unit 2, and the 276 fuel assemblies installed in Peach Bottom Unit 3 are damage free.
By preventing fuel damage, the Defender Debris Filter decreases personnel radiation exposure, increases electric generating capacity, and maximizes use of reactor fuel rods. Exelon estimates the use of the filter will reduce exposure 1 to 10 person-rem and avoid $7.25 million in costs over each plant’s two-year fuel cycle.
• PSEG Nuclear LLC employees at the Salem nuclear power plant were recognized with the Westinghouse Design Vendor Award for their Mechanical Stress Improvement Program (MSIP) that mitigated cracking of metal welds on reactor vessel nozzles. The MSIP process compresses the outside of a pipe, and subsequently compresses the inside of the pipe, to eliminate tensile stresses that contribute to stress corrosion cracking. PSEG partnered with Westinghouse to implement MSIP and successfully completed the mitigation of all eight Salem Unit 1 reactor vessel nozzles in less than six days in the fall 2008 maintenance outage. It marked the first time MSIP was successfully performed on nuclear plant piping of this size.
Through the successful completion of MSIP at the New Jersey power station, PSEG has developed an innovative solution that has lead to a 10-year inspection cycle on the Salem nozzles. This schedule will reduce worker exposure by 5 to 10 person-rem and reduce costs. The MSIP application at Salem 1 saves $3.6 million when compared to other mitigation techniques.
• Omaha Public Power District employees at Fort Calhoun were honored with the Westinghouse Combustion Engineering Design Vendor Award and the nuclear energy industry’s B. Ralph Sylvia Best of the Best Award for the use of eddy current testing to assess the susceptibility of stainless steel and inconel alloys to stress corrosion cracking (as described above).
TIP PROCESS AWARDS
• Duke Energy employees won the Community Relations Process Award for implementing a public outreach program at all of its nuclear energy stations, including the proposed William Lee nuclear plant near Gaffney, S.C. The program’s goal is to educate the public and instill confidence in the safety, reliability and cost-effectiveness of nuclear energy. All outreach efforts focus on activities that are education-driven, sustainable, cost-efficient and easily adaptable to different audiences and locations. Original outreach programs focused on students and neighbors. The program has been expanded to include real estate agents, community leaders, Boy Scouts and Girl Scouts, preschool children, teachers, wildlife organizations and others.
Features of the public outreach program include: energy education centers, art show exhibitions, McGuire Nuclear Station Homeschooler’s Day, Oconee Outdoor Family Adventure Festival, Catawba Pen Pal Project, family tour days, community newsletters, employee newsletters, employee meetings, science teacher workshops, school presentations, Movies at McGuire, Take a Child Outside Day, Charlotte Symphony Event at the McGuire nuclear plant (6,000 attendees in 2008), Oconee Arts Partnership, and annual “state of the plant” update meetings. The effectiveness of the program is measured through annual community surveys. Virtually every activity that comprises Duke Energy’s outreach program is transferable to the rest of the U.S. nuclear industry.
• Exelon Nuclear employees collaborated with Plastocor Inc. to earn the Equipment Reliability Process Award for managing condenser tube aging with internal epoxy coating. Main condenser tubes are subject to several modes of degradation over time. The most significant degradation mechanism is microbiologically influenced corrosion (MIC) that can cause pitting and penetrations through tube walls. Replacing main condenser tubes takes 60 to 100 days, costs $50 million to $80 million, and produces up to 70 person-rem exposure for boiling water reactors. The epoxy coating application can arrest MIC and repair leaking tubes, including tubes that were previously plugged due to leakage.
Exelon partnered with Plastocor Inc. to improve the condenser tube application that has been used in fossil plants. The inside of each tube is cleaned and dried. The epoxy is then injected into the tube and applied by a squeegee that is either propelled by air or pulled with a string through the tube. The epoxy coats the entire inner surface of the tube and plugs any holes. The thin coating prevents MIC, has little effect on heat transfer, and initial tests indicate that formerly plugged tubes can be returned to service. Exelon has four nuclear plants that may need to have their main condensers tubes replaced by 2014. A viable alternative is the in-situ epoxy coating of the tubes. Exelon estimates it will save at least $400 million and reduce radiation exposure to workers by a minimum 300 person-rem. Exelon is the first electric utility to apply in-situ epoxy coating to the main condenser tubing at nuclear plants.
• Entergy Nuclear employees at the Vermont Yankee nuclear energy plant are recipients of the Maintenance Process Award for developing innovative tooling for the inspection of a boiling water reactor steam dryer. The steam dryer is located in the top of the reactor. Working with Entergy Nuclear at Vermont Yankee, AREVA NP Inc., designed two remotely operated inspection systems, one to inspect the outer diameter (OD) of the dryer and the other to inspect the inner diameter (ID). The HawkEYE II Remote Mechanized Steam Dryer OD Inspection System uses a rail and trolley system with a telescoping mast and camera to inspect all 213 welds and components. The ROCKY ID Remote Mechanized ID Inspection System uses an underwater crawler with a telescoping mast and camera to inspect all 253 welds and components.
Advantages common to both inspection systems include: improved safety, higher inspection quality, greatly reduced radiation exposure and parallel inspection capability. An annual reduction of 3.6 person-rem of radiation exposure is expected along with a minimum $500,000 cost reduction per outage. The tooling is highly transferable. It was developed so it can be used on all makes and sizes of dryers, regardless of the rail configuration on the refuel floor. The new dryer inspection tools can be used for dryer inspections at all boiling water reactors.
• Exelon Nuclear employees earned the Nuclear Fuel Process Award for their Next Generation Core Design strategy for boiling water reactors. Collaborating with Global Nuclear Fuel (GNF), the team developed a multifaceted approach that improves reactor core designs. The challenges addressed include: minimizing reactivity manipulations by operators, meeting the demand for long fuel cycles with high energy demands, managing increasing uranium prices, and minimizing control rod interference with fuel assemblies.
The next generation core designs provide important benefits. Safety is improved by eliminating at least four reactivity manipulations per two-year fuel. Also, fewer control rods need to be inserted into the fuel, thus minimizing interference with fuel assemblies. And fuel cycle economics are improved through fuel cycle extension techniques that reduce the number of, or uranium concentration of, replacement fuel assemblies.
Fuel cost savings for Exelon BWRs that fully implemented Next Generation Core Designs from 2006 through 2008 was approximately $55 million. Outage time for maintenance has been reduced because fewer new fuel assemblies are loaded into the reactor. There also are back-end fuel cycle savings through a reduction in the amount of used fuel that is generated. The strategy also improves fuel efficiency by placing fuel assemblies entering their third cycle of operation in the outer three rows of fuel assemblies. This has a secondary benefit of extending the use of the reactor pressure vessel and internals by reducing their radiation exposure.
Exelon’s core design strategy is applicable to other boiling water reactors.
• Duke Energy employees at the Catawba nuclear station and AmerenUE employees at the Callaway nuclear plant shared the Materials and Services Process Award for the use of high-density polyethylene piping for plant service water systems. South Carolina’s Catawba station was the first U.S. nuclear plant to use polyethylene piping for the replacement of a water system. Missouri’s Callaway was the first U.S. plant to use polyethylene piping in a nuclear safety-related application. Unlike carbon steel piping, high-density polyethylene piping is not subject to corrosion, and it eliminates the need for system pipe cleaning that increases costs and decreases system availability. It also is less costly to install and maintain.
In 1998, Duke Energy employees at Catawba replaced six-inch, low-pressure water piping that provides cooling water to the generator hydrogen coolers. Following the replacement of more than 90 percent of the carbon steel piping with polyethylene piping, flow in the system greatly improved. Catawba is planning to replace 4,000 feet of buried, 10-inch carbon steel piping in the safety-related water system. The use of polyethylene piping will cost $12 million less than the alternative molybdenum piping, and it offers the long-term benefits of being non-corrosive and not requiring cleaning. In 2008, AmerenUE employees at Callaway successfully used high density polyethylene piping to replace 1,600 feet of underground piping in the safety related essential water system (EWS). The original carbon steel piping required numerous inspections and costly repairs. Callaway completed the replacement of one-half of the buried EWS piping in just eight days in December 2008. It will replace the other half in 2009.
Both Catawba and Callaway share information and technology with the nuclear industry for the use of polyethylene piping as a safe and cost effective alternative for replacement of service water piping systems. Their findings and achievements can yield benefits to the entire U.S. nuclear industry, including new nuclear plants.
• Exelon Nuclear team members earned the Operate Plant Process Award through their development of a modification to the handles of ball valves. A ball valve handle is designed for ease of operation, but the handle can be inadvertently bumped, causing the valve to be mispositioned. By shortening the ball valve handle so it no longer protrudes, the risk that it will be bumped is eliminated. This also removes the risk of worker injury through impact with a handle. Simple, inexpensive tools can be used to operate the modified valves.
Exelon Engineering developed a process to change the handles and greatly reduce engineering time and labor. The process saves at least 40 person hours for each valve modification compared to other modification options. Over Exelon’s 17 reactors, the new ball valve handle modification process will save at least $2.38 million and 1 to 10 person-rem of radiation to workers. All U.S. nuclear energy plants can use this effective innovation.
• Exelon Nuclear employees won the Plant Support Process Award for their initiative to improve the performance of its supplemental workforce. Prior to fall 2007, Exelon’s outage planning and services was not performing to the same level of excellence as the Exelon fleet as a whole. The goal was to improve their performance to reduce errors and improve safety and efficiency. Beginning in September 2007, Exelon integrated its Alliance partners (AREVA, GE, Shaw, Siemens, Westinghouse) into this outage human performance program. In 18 months, training was provided to more than 3,000 supplemental workers, and more than 18,000 observation cards allowed for daily and historical outage performance trending. The trends were communicated daily to all Exelon and alliance partner managers, supervisors and appropriate supplemental workers. Performance Indicators were developed to measure outage performance, enabling Exelon and its alliance partners to monitor and adjust performance.
The initiatives taken by Exelon and its alliance partners improved safety and worker performance, and reduced radiation exposure and costs. In 2008, the number of worker-related events dropped 67 percent from 2006. The alliance partners experienced significant event declines as well. A total reduction of 100 person-rem of radiation exposure was achieved for the 2008 outage season. Outage days over schedule fell by 38 percent from 2007 to 2008, and $8.2 million was saved in 2008. This cooperative effort is a model that can be used throughout the industry.
• Entergy Nuclear corporate employees were honored with the Management Processes and Support Services Process Award for their formation of the Innovations Group. The purpose of the Innovations Group, launched in 2008, is to identify opportunities to use cutting-edge technologies and concepts at the company’s nuclear power plants. The group is comprised of employees with diverse backgrounds and excellent teamwork skills who demonstrate “out-of-the-box” thinking and innovative problem solving. Team members have direct plant experience in operations, information technology, radiation protection, emergency planning and maintenance.
The Innovations Group’s main areas of focus are process improvement, automation & wireless technology, on-line equipment monitoring, university R&D and vendor partnerships, plant upgrades and modernization, organizational efficiencies, and advanced nuclear technology. Ideas come from internal sources and external sources not limited to the nuclear industry. Some of the major improvements implemented by the Innovations Group in its first year include implementation of SmartSignal Predictive On-Line Monitoring at Waterford 3 to prevent major equipment failures; wireless technology to connect the River Bend plant’s intake structure to the control room; and piloted “business genetics” with a potential to reduce 13,000 work-hours per year.
Entergy is the first company to implement a group of subject matter experts dedicated full-time to driving innovation across all nuclear energy departments. The Innovations Group concept is transferable to all nuclear energy companies.
• Exelon Nuclear employees were recognized with a Nuclear Training Process Award for their Web Qual Tools that allows workers and their supervisors to easily check the status of their qualification data and facilitate requalification training as needed. The Web Qual Tools program created one qualification management system for the entire corporation and provided all individuals with easy access to their qualification data. Individuals can simply check a web link or use strategically placed touch screen Web Qual Kiosks to quickly view their qualification data. Each Exelon nuclear plant site has three web Qual Kiosks. The system also enables supervisors to quickly check the status of their workers qualifications, improves the scheduling of training, provides web courses and web exam hosting, produces individual and department reports, forecasts and schedules.
Since its implementation Web Qual Tools has improved safety margins and reduced costs by preventing rework of activities. Likewise, the reduction in rework has reduced personnel radiation exposure by at least four person-rem per year, per site Because of its ease of operation, the system saves the corporation $6.1 million a year in employee time spent checking qualifications, and an estimated $350,000 per outage.
The Web Qual Tools were copyrighted based on strong interest from the nuclear industry and other business sectors. Exelon is working to license Web Qual Tools.
TIP VISION & LEADERSHIP AWARD
• Exelon Nuclear employees are recipients of a special combined Vision & Leadership Award for its international technical exchange program and industry group leadership and industry participation plan.
In its international technical exchange program, Exelon Nuclear has partnered in technical exchange with three of the largest international nuclear utilities: Korea Hydro and Nuclear Power Co. (KHNP), Tokyo Electric Power Co. (TEPCO), and Electricity de France (EDF). Together, the four companies represent 22 percent of the nuclear energy plants worldwide. All four have benefitted from sharing operating experience, best practices, lessons learned, equipment reliability, risk management, predictive and preventative maintenance. Lessons learned by Exelon from its three counterparts regarding new plant construction will save more than $200 million with its potential new plant in Texas.
With its industry leadership and industry participation plan, Exelon Nuclear works collaboratively with numerous industry counterparts to solve technical issues confronting the industry. It also stays abreast of emerging technologies and developments that can improve safety and performance. Exelon has more than 100 primary and secondary advisors that perform leadership and support roles in organizations including; Electric Power Research Institute, Institute of Nuclear Power Operators, PWR Owners Group, BWR Owners Group, Nuclear Energy Institute, and others. They participate in boards of directors, executive committees, advisory councils, committees, subcommittees, task forces, working groups, etc. Solving problems and addressing industry issues have implications for the entire industry.