Doing It Right: the Loviisa Way by SIMON RIPPON Impressive Performance at Loviisa in Finland
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Doing it right: The Loviisa way BY SIMON RIPPON Impressive performance at Loviisa in Finland OVIISA NUCLEAR POWER station in stems from good management decisions, involvement Finland has one of the best, if not the L best, operating performance records in of plant personnel, efficient outages, and the world. The cumulative capacity factor for Unit 1 since the start of commercial operation reliance on the expertise of many companies. in 1977 is 84 percent, and for the last 19 years, the annual figure has five times been above 90 large-diameter containment was required to From a maintenance point of view, these percent and has never been below 80 percent. accommodate the six-loop VVER-440 plant, unique features of the Loviisa plant have pre- For Unit 2, the cumulative load factor since with its horizontal steam generators. This led sented quite a challenge, both to the plant op- startup in 1980 is 87 percent, with eight of the to the adoption of an ice condenser system to erators and Finnish regulators, and it was for last 16 years above 90 percent and only one provide pressure suppression rather than a full this reason that they decided from the outset that year below 80 percent (at 79.2 percent). pressure containment. they must learn to do things themselves. This Other performance indicators are equally impressive, including the collective radiation doses, which have been at or below 1 person- sievert per year per unit for most of the oper- ating lives of each of the two reactors, and the duration of refueling outages, which have been progressively reduced to a record 15.5 days at Loviisa-1 in 1997. When the plant’s general manager Arvo Vuorenmaa—who from 1984 to the end of last year was maintenance manager at the plant— was asked, “What have you been doing right?” he cited three main factors that have con- tributed to Loviisa’s excellent performance: I “A good management decision was made very early on that we should learn to do things ourselves. That meant that even during the construction and commissioning, our engi- neers were very heavily involved in the process. And this formed a very good basis for subsequent operations.” I “Early on we learned how important it is to have really short and efficient outages. In the early ’80s, shortly after commissioning, we started to plan how could outages be done in a short time and with high quality.” I “We involved many companies so as to have competition. Already during construc- tion many Western companies were involved, so we could utilize the knowledge of these companies and we have been able to improve the plant progressively.” In many respects, Loviisa is a unique nu- clear power station. It is equipped with two VVER-440 pressurized water reactors sup- plied by the former Soviet Union, and each unit has two turbo-generator units also of Russian/Ukrainian supply. But the Finns in- sisted on Western-style reactor containment rather than the confinement and bubbler con- denser system provided for contemporary VVER-440s in eastern Europe. In addition, they sought Western suppliers for the instrumentation and control systems and contracted a substantial proportion of component design and manufacture to very competent Finnish engineering companies. A The two-unit Loviisa nuclear power station in Finland (Nuclear News photo by Simon Rippon) October 1999 NUCLEAR NEWS 29 Turbine maintenance under way at Loviisa-1 (Loviisa photo) included the original development of mainte- hand, Vuorenmaa pointed out that the Soviet denser chambers and placing it back in the ice nance schedules, which, Vuorenmaa says, in- components are very sturdy. “I would say this baskets. volved a very great effort during the plant con- combination of Soviet mechanical compo- Another unique situation has arisen with struction. The international diversity of original nents, which have high margins, and Western some of the Finnish-supplied components, no- equipment supplied has also led to a wide in- instrumentation is a very reliable combina- tably the primary circulation pumps. These are ternational spread of maintenance contractors tion.” This is particularly the case with the controlled-leakage pumps instead of the from Russia, western Europe, and the United turbines and the steam generators—it has canned motor pumps adopted on other VVER- States. only been necessary to plug two steam gen- 440 plants, and were developed and fabricat- Design features of the Loviisa plant pose erator tubes in 25 years, and these, Vuoren- ed by one of Finland’s highly qualified engi- good and bad news for maintenance opera- maa said, were due to original manufacturing neering companies. But after the Loviisa order tions. Six primary loops and two turbo-gen- defects. for 14 pumps (six for each reactor and two erators per unit is the main bad news. “Too Bad news from the Western equipment side spares), there were no more customers for many valves!” declared Jorma Aurela, the includes one of the most tedious maintenance these pumps, and the company no longer pro- Loviisa communications manager, who has tasks that has to be carried out every year on vides maintenance support. And so, this is one also been involved as a safety engineer with the ice condensers. This involves hacking off of the regular maintenance tasks that has to be licensing issues on the plant. On the other the ice that builds up on the walls of the con- carried out in well-equipped electrical and me- chanical workshops at Loviisa. Maintenance goals “The main goal here,” Vuorenmaa says, “is to make sure that the plant remains in safe and reliable operation for the period of the li- cense.” In effect, plant life management is an integral part of the maintenance program. There are two things that have to be taken care of to reach these goals. First, there is the con- fidence of the public—which, of course, in- volves the safety of the plant. “And,” Vuoren- maa says, “it is not just a case of convincing the public, we have to convince ourselves and make sure that the plant is safe.” The other thing that has to be taken care of is the economics. “And here we have to con- vince the owners [Fortum] of the situation,” said Vuorenmaa. There is already a very com- petitive free market for electricity in the Nordic countries, he added, and it is necessary One of four turbines at Loviisa that are being progressively uprated from 508 MWe each to 516 to maintain the competitive position of nu- MWe, between 1998 and 2002 (Nuclear News photo by Simon Rippon) clear electricity. 30 NUCLEAR NEWS October 1999 THE LOVIISA WAY the system, that person acts as a coordinating foreman to whom the managers and foremen of outside contractors report. “So it is developed from the inside at every level,” Vuorenmaa says, “. every day, small decisions are made—should we repair this, should we redesign that, what should we do with this—and there are always our own people involved in that decision sit- uation. If all the decisions are made by our people then they are responsible for the consequences.” Vuorenmaa himself assumed responsibili- ty for developing this philosophy when he be- came maintenance manager at Loviisa in the early 1980s. “We have the three goals from the operational point of view: The first goal is minimum disturbances during operation— that’s the main goal; the next one is minimal duration of the reload and these two, I think, can conflict a little. To take care of these con- flicts, I decided that if a decision has to be made that some work needs to be done, at least it will be accepted by those responsible The top of one of the ice condensers at Loviisa-1, where the maintenance task of chipping ice off the for operation. And the third goal, which I walls had already commenced before the annual refueling outage (Nuclear News photo by Simon Rippon) think is becoming stronger, is that we should have the outages during the summer.” To meet these goals, Vuorenmaa said, “we water inventory and generous safety margins. In the competitive Nordic market, the make plans for the next year and the coming Vuorenmaa thinks that the organization of prices of electricity in the summer are very 10 years, and we must take care of both these maintenance at Loviisa “is to some extent much less than in winter. So all decisions, sides [safety and economics].” very different to many other countries. The even those concerning the duration of the out- Vuorenmaa believes that “the main tool to- main idea here is that the same people who are age, should be made with a view to avoiding day from the safety point of view is PSA responsible for the operation are also respon- any interruptions in operation during the win- [probabilistic safety analysis].” Loviisa main- sible for the maintenance. This sounds like a ter. For the last 10 years, the outages for the tains a living PSA to show the effectiveness simple thing, but I think it is important. We two units have been in August and Septem- of different maintenance and improvement are still using a lot of outside contractors— ber. There is now some pressure from Fortum measures in reducing the hypothetical core there are about 800 additional people work- to change to July and August, although this melt frequency. From 1990 to 1998, there was ing during an outage, and the maintenance may be unpopular since July is the main hol- an impressive thirtyfold reduction from just staff at the plant numbers about 200.