Nuclear, Reactors

The four Ps of outage management

Issue 1 and Volume 100.

The four `Ps` of outage management

By Steven E. Kuehn, Senior Editor

Boasting the best production costs in a decade, the U.S. fleet of nuclear reactors is performing better than ever. Industry wide, production costs fell 7 percent to $20.02 per net megawatt hour (MWh) and output climbed 3 percent to 634 million MWh. It doesn`t take a nuclear physicist to realize that when base-loaded nuclear units are operated for long periods of time, near their technical potential, costs will fall and relative performance improves.

Statistics for 1994 compiled by the Institute of Nuclear Operations (INPO) and the World Association of Nuclear Operators (WANO) showed the industry has steadily improved in most of the 10 industry-recognized categories. In 1994, Unit Capability Factor (the percentage of maximum energy generation a plant can supply to the grid) reached just under 82 percent, beating the 1995 goal and proving just how far the industry has come (62.7 percent in 1980) when improving plant operations.

Controlling outages

Unit Capability Factor is limited only by the factors within the control of plant management. Among the factors that impact this measure of nuclear unit performance is the refueling outage, a fundamental and mandatory operation for all pressurized and boiling water reactors (PWR/BWR). Conducted on a fixed schedule with the reactor shut down, cutting outage length to a minimum has, for the past several years, been an operating goal as well as a performance goal-post for those U.S. utilities fielding nuclear units.

Reducing downtime from refueling outages is one of the most effective ways to trim costs and increase overall performance. Every day a nuclear unit is off line it can cost approximately $300,000 (source: Nuclear Energy Institute) in direct costs and does not include replacement power costs that could easily equal that amount. If one really crunched the numbers hard, it`s likely that every day trimmed from an outage schedule means about $1 million in deferred costs and associated risk.

Average refueling outage duration figures have nearly been cut in half since 1989. Today, the median stands at 48 days, a week less than 1994 and a month better than the 1989 average. All of this might not seem as impressive if exchanging reactor fuel was the only task being conducted during an outage. Refueling outages typically include a great deal of maintenance, repair, modification, and safety system verification activity. Logically enough, such operations are carried out at this time because the unit has to be shut down for refueling anyway, but with so many things to accomplish in a given timeframe, there is a great deal of pressure to expand the schedule.

Utilities operating nuclear units have become extremely adept at managing the refueling outage and have, for the past few years, applied the latest concepts in project planning and preparation to shrink schedules and get more work done at the same time. Solutions have also come from vendors and other engineering sources within the industry. Partnering and closer, more direct relations with primary and sub-contractors also have borne the desired fruit of reducing schedules. New computer-aided design (CAD) tools and information technologies (IT) have joined the party as well, and have revolutionized the way utilities prepare for an outage. Indeed, planning, preparation and partnering are three of the four “Ps” that prevent poor outage performance.

Commanding all the technical and organizational elements and mobilizing the hundreds of people to accomplish the myriad of tasks involved in a refueling outage is no mean feat, but some recent record-breaking outages have shown that there are utilities with staffs that really know how to manage it all. Case in point is PECO Energy`s Limerick Unit 2, a 1,163-MW GE BWR located in Montgomery County, Pa. Personnel at the plant recently completed the unit`s third refueling outage in a spectacular and record-breaking 22.8 days.

2R03

Known internally to PECO Energy as 2R03, planning for Limerick`s outage began well in advance of the Jan. 27, 1995, start date. According to David Helwig, then vice president of Limerick, “we planned and scheduled every detail of the outage well in advance, further in advance of the start of an outage than we had ever done before.” Helwig characterized the outage as a model example of a refueling outage in terms of both planning and execution. “We would not have been able to accomplish this feat without the superb teamwork and coordination of hundreds of PECO personnel and contractors.”

For the record, the 22.8-day outage is the best ever logged by any of the 53 GE-designed BWRs in the world. It beat the previous 23.6-day outage record attained by Monticello 1, a 543-MW unit in 1981. Other than Limerick Unit 2 and Monticello 1, only two other small GE BWRs have ever approached the low 20s mark. The shortest refueling outage completed by a PWR of comparable size to Limerick was 31 days.

Teamwork equals success

Helwig said he was very impressed with the teamwork displayed by PECO Energy and contractor personnel. He cited PECO Energy`s Nuclear Maintenance Division as particularly competent and also mentioned the support the plant got from another nuclear unit in PECO Energy`s system. Acknowledging the importance of partnering with suppliers, Helwig said the company`s success was dependent on the skills and efforts of a significant number of contractors including GE, Bechtel, Raytheon, Hennigan, Hake, Atwood & Morill, Bartlett, GTS Durateck, NPS, Regal Instruments Inc., Underwater Engineering, Wackenhut, Rust and Freeze Seal Engineering.

Walt McFarland, then director of outage management (now vice president of the plant), said Limerick was better prepared for 2R03 than any BWR has ever been for an outage. “Our detailed outage schedule was prepared three months before the start of the outage and that gave us ample time to develop innovative process that helped shorten 2R03.”

Among the innovations mentioned by McFarland:

Work group tagging. On specific, well-defined jobs, craft personnel were allowed to apply and remove their own clearances.

Integrated system restoration. Teams comprised of a system manager and a cross section of personnel from operations, maintenance instruments and controls, and health physics were responsible for performing all work directly related to returning the emergency core cooling system to service.

Island clearances. Entire systems were blocked out for maintenance under one clearance instead of using many individual clearances to block out specific sections at different times.

Despite being one of the shortest refueling outages on record, 2R03 was done at a relaxed pace. According to Make-It-Happen Manager Tony Coppa, “a lot of activities were done in parallel and that helped keep things moving.”

Challenges

Each department involved in 2R03 had challenges to meet. Tom Shea, Instruments and Controls manager, said his group`s biggest hurdle was developing ways to complete the same amount of outage work in a shorter amount of time. “Significant reductions in job duration were achieved through innovative thinking which resulted in revision of traditional schedules and procedures,” he said. “This was possible through input and up-front planning involving technicians who readily identified areas for improvement,” said Shea, “and in conjunction with good support from all site work groups including scaffold builders, health/physics, staff from our other plant, Peachbottom and operations, enabled us to overcome challenges and complete the work.”

Mike Gallagher, shift outage director, contrasted 2R03 to the last refueling outage performed on Limerick`s Unit 1, 1R05. He said the difference between 2R03 and 1R05 was that plant personnel improved their performance in potential stumbling areas such as drywell entry, cool down, flood up, drain down, feedwater check valve work, hydro, main steam isolation valve (MSIV) work and start up. “We prepared for all those activities as well as many others so they wouldn`t prevent us from reaching our goal,” Gallagher said.

Gallagher added that drywell entry, the first outage activity following reactor SCRAM (shutdown) was, in his opinion, a prelude of how well the outage would go. “I believed if drywell entry went smoothly the outage would go smoothly,” he said. “We made initial drywell entry within nine minutes following the SCRAM. Maintenance department`s Joe `Moses` Cook parted those shield doors like the Red Sea and got 2R03 off to a great start.”

Secrets for success

At an internal presentation to GE staff, Al Jenkins, GE site representative, cited several reasons why Limerick`s outage was so successful and why the fourth “P,” people, are so important to the process. Among his remarks, Jenkins said “Limerick has a philosophy which requires decisions to be made promptly. This, in turn, requires people to quickly communicate problems, issues, barriers, etc.” He noted that tactics such as establishing a military-style command and control center and developing IT as a tool (Limerick has a computerized work management system) to monitor work status in realtime are some of the primary things that helped Limerick achieve its outage goals in record-breaking time.

Ken Hunt, senior outage manager, said 2R03 was the “culmination of all our efforts over the past several years to improve outage performance.” He said that early work planning and early scheduling contributed a great deal by allowing the work force, particularly foreman and first-line supervisors, to figure out just exactly what they had to do and how they were going to do it. Kevin Carrabine , manager of unit outages, pointed out that all pre-outage milestones and schedule preparation were achieved earlier than ever. For example:

-Scope identification was completed 10.5 months ahead of the outage compared to 8 months for 1R05.

-Clearances were written 3.5 months ahead of 2R03 compared to 1.5 months for 1R05.

-The Rev O plan (which is the executable outage plan) was issued three months before the start of 2R03 compared to 1.5 months for 1R05.

Major tasks

Major tasks in 2R03 included a five-year overhaul of the high-pressure turbine, disassembling and inspecting the low-pressure turbine, removing and replacing 14 main steam relief valves, modifying inboard main steam isolation valves, replacing 19 control rod drives, completing 133 leak rate tests and cleaning more than 100,000 condenser tubes. Overall, approximately 8,000 tasks were carried out, including modifications to feedwater check valves and improvements to the emergency water system.

The outage to-do list also included all refueling operations which involved installing 276 new fuel bundles (plus 80 from the decommissioned Shoreham plant). Refueling floor operations, said Limerick managers, went extremely well and they attributed it to the 100-percent availability of two key maintenance-related systems: the refuel platform and the refuel floor crane. According to one engineer, the 100-percent availability of a system as intricate as the refuel platform, with its incumbent mechanical and electromechanical/electronic elements, was somewhat remarkable.

Other technology, some complex and some not so complex, facilitated refueling operations as well. For instance, an innovative tool called the reactor head carousel helped save time and money. The carousel was designed to de-tension the reactor head and automatically remove the 50-pound nuts and 15-pound washers and put them on a rack, a task that is tedious and time consuming.

Another bit of lateral thinking involved fabricating a sturdy staircase for people to enter and leave the area. Not only was this approach safer than the previously used ladder, but it constantly saved one of this outage`s most precious elements, time.

Diablo Canyon

Pacific Gas and Electric (PG&E) followed the four “Ps” with a similar best-practices attitude to complete Diablo Canyon Unit 2`s sixth refueling outage (2R6) in a record 34 days, 10 hours. Making PG&E`s achievement even more remarkable is the size of the reactor and its type, 1,000-MW four-loop Westinghouse PWR, and the fact that the job came in $10 million under budget. Costing approximately $42 million, last year`s outage was also the company`s most cost-efficient in plant history. According to PG&E, during 2R6 records tumbled like matchsticks in the wind with man-rem exposure 28 percent below target and low-level radwaste production down 41 percent.

Action forums

PG&E said the success of this outage was due in part to its team-based, continuous improvement work culture fostered in the late 1980s. An outgrowth of that program now in place are project management groups called Action Forums, a staff-mobilizing and organizational concept used to help plan and effectively manage the fluid and intense dynamics of a large-scope outage. Brainstorming Action Forums considered more than 300 ideas for improving work processes and recommended shaving off an additional eight days from the original 49-day schedule.

Tighter goals, work improvements and scope reduction ideas brought forward by the Action Forums set the agenda for the outage and also set the tone. With refreshing frankness, PG&E admitted that at the outset of this outage, many were still very skeptical of a 41-day schedule. However, once the outage got under way a “can do” attitude soon took over, evolving into the 34.4-day record.

This outage was never “plain vanilla” either said PG&E. More than 160 design changes and 8,000 significant work package activities were incorporated into the 258,000 manhours logged during 2R6.

Major work included inspecting the unit`s diesel generators, inspecting 100 percent of the unit`s four steam generator tubes, and replacing major instrument and control systems, control room annunciators and 2,000 feet of steam piping. Of course, refueling operations were conducted as well and went off without a hitch.

Warren Fujimoto, vice president and Diablo Canyon`s plant manager, commented that “when Unit 2 paralleled the grid last October, it demonstrated what the right planning, people and resources can do. It also showed that we have the capability and determination to meet the tough challenges of the future.”

Tough future challenge indeed, considering the rate of utility restructuring in California and the competitive pressure being applied to any utility operating a nuclear unit. Though obviously very satisfied with everyone`s performance during 2R6, Fujimoto said the stage is now set for even better performance with typical outages lasting 30 days and costing $30 million. Fujimoto said that is what it`s going to take to stay competitive, and he vowed that is what Diablo Canyon`s employees will be empowered to do.

People power

It is increasingly obvious that utilities operating nuclear units are becoming quite adept at keeping the twin wolves of escalating operating and maintenance costs and increased competition at bay. Is it a sustainable effort? It seems likely that it is possible, especially if outage numbers keep dropping and other performance indicators sustain their positive trend. For now, however, operational performance at all nuclear plants is being sustained at levels thought unattainable just a few short years ago, driven by the incredible drive and motivation of the fourth “P” identified throughout this story, people. z

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PECO energy technicians tighten the drywell head fasteners following the head`s re-installation. Note the reactor cavity stairway–a simple solution to the problem of transporting men and material in and out of the space.

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A beautiful plant on a beautiful day, PG&E`s Diablo Canyon plant trimmed its latest refueling outage to an equally attractive 34 days.