A Survey on the Maintenance Demand of Nuclear Power Plants in Korea
公開日:
カテゴリ: 第2回
1. Introduction
Section 5, we present summary and conclusion from the questionnaire result.1. IntroductionRecently, most of NPP companies have been targeting several areas to improve their productivity actively. Improving availability of the plant, shorter outages and a significantly lower reactor trip had all contributed to higher output of the plant. However, there is a limit in the improvement to gain higher output. For that reason, they have been considering the improvement of maintenance work [1], [2]. The object of this research is to do preliminary investigation of the NPP maintenance technology development. For the work, it is necessary to know the current maintenance environment in Korean NPPs. Also, it is very important to get the plant operators and staffs’ opinions for the research. To get their opinion, we carried out the questionnaire investigation. The structure of this paper is as follows. In Section 2, we introduce the present state of Korean NPPs. The questionnaire contents are introduced in Section 3. The result of the questionnaire is presented in Section 4. InPOC: 373-1 Guseong-Dong, Yuseong-Gu, Daejeon, Korea 305-701, Center for Advanced Reactor Research, Korea Advanced Institute of Science and Technology, Tel: +82-42-869-3860, Fax: +82-42-869-3849, e-mail: wahrheit@kaist.ac.kr d of Nuclear Power Plants in Koreaearch, Korea Advanced Institute of Science andand Quantum Engineering, Korea Advanced\uantum Engineering, Korea Advanced InstituteC....del N..len. Dawa2. Nuclear power plants in KoreaTable 1 shows the NPP sites in South Korea [3]. South Korea has 4 sites and 20 commercial nuclear power plants. The first three commercial units - Kori 1 & 2 and Wolsong-1, were bought as turnkey projects. The next six, Kori 3 & 4, Yonggwang 1 & 2, Ulchin 1 & 2, comprised the country's second generation of plants and involved local contractors and manufacturers. At that stage the country had six Pressurized Water Reactor (PWR) units derived from Combustion Engineering in USA, two from Framatome in Europe and one from AECL in Canada of radically different design. Then, in the mid 1980s, the Korean nuclear industry begins a plan to standardize the design of NPPs and to achieve much greater self-sufficiency in building. In 1987, the industry entered a ten-year technology transfer program with Combustion Engineering (now Westinghouse) to achieve technical self-reliance, and this was extended in 1997. A sidetrack from this was the ordering of three more CANDU-6 Pressurized Heavy Water Reactor (PHWR)303TypeTable 1. Power reactors operating in Korea Name ReactorOperation PWR1978/04/01PWR Kori7/83 PWR9/85 PWR4/86 PWR9788 PWR9789 PWR1998/06/01(KSNP) UlchinPWR6/99 (KSNP) PWR1/04 (KSNP) PWR12/04 (KSNP) PHWR4783PHWR Woisong6/97 PHWR6/98 PHWR6/99 PWR8/86 PWR6/87 PWR0.126315789473684(Syst 80) YonggwangPWR3/96 (Syst 80) PWR5/02 (KSNP) PWR6(KSNP) units from AECL in Canada, to complete the Wolsong power plant. These units were built with substantial local input and were commissioned from 1997 to 1999. In 1987 the industry selected the CE System 80 steam supply system as the basis of standardization. Yonggwang 3&4 were the first to use this, with great success. A further step in standardization was the Korean Standard Nuclear Plant (KSNP), which from 1984 brought in some further CE System 80 features and incorporated many of the US Advanced Light Water Reactor design requirements.3. Questionnaire for the researchThe questionnaire for the survey is classified to 4 parts.(1) Present state of the maintenance in Korean nuclear power plant In this chapter, we survey on Korea Hydro & Nuclear Power Co., LTD. operators and staffs' opinion of the current state of maintenance. The contents for this chapter are the self-supporting level and the level of the maintenance technology in Korean NPPs in comparison with other countries. The maintenance technology items are classified into 5 items:? Management technology: The technology related to theequipment failure prevention, and maintaining the equipment in optimum condition. For example,improvement of operating method, environment, etc. Prediction of the equipment failure and condition monitoring technology: The testing, diagnosis, and evaluation technology for the equipment failureprediction and detection. ? Repair technology: Equipment assembly, disassembly,and replacement technology. ? System engineering technology: The technology toimprove existing equipment's performance,reliability, and safety. ? Integrated maintenance management technology: Themanagement technology to reduce operation and maintenance cost and maximize its effect.The answers for those questions are “very low““, ““low”, ““normal““, ““high”, and “very high”. The urgent needs to perform improvement of the equipment are inquired in the last of this chapter.(2) Present state of the preventive maintenance In this chapter, we want to know the obstacle of the overhaul period reduction. In the analysis, we divided the result into 2 cases; PWR case and PHWR case.(3) Development maintenance technology This chapter shows the technologies which are needed in the current maintenance work. The technologies are classified into 3 contents - maintenance planning, implementation, and equipment improvement. In the last part of this chapter, the degree of necessity of the predictive maintenance technology is inquired. Most of NPPs perform the preventive maintenance. However, it is found that many NPP maintenance staffs think that some maintenance resources are wasted and some activities are not needed. In addition, they think that some equipments can be in worse conditions after performing preventive maintenance. Therefore, equipment condition based predictive maintenance is needed to be considered in NPP industry to optimize the reliability and the availability of equipments.(4) The demand for specific equipment maintenance technology This chapter shows the specific system or components which are needed for the maintenance technology of the specific system, structure and component in NPPs in terms of the condition monitoring, on-line maintenance, and shortening of the overhaul.4. ResultWe carried out a survey on 86 operators and staffs in 8 units; 13 in Kori 2, 32 in Ulchin 1-3, 23 in Wolsung 1&2,304Vesy ft0.339Noernal, 22:6%Hch53.1Fig. 1. Self-supporting levelIntegrated maintenancemanagementSystem engineeringRepairPrediction of equipment failure and conditionmonitoringMaintenance management0.20.6ma Very High Bros a Noa Down Veay LoveFig. 2. Present state of nuclear power plantmaintenancePOCotcomsexnert for bialyse 57%interest of manager2.14Ersun and manpower. 59.5Fig. 3. The urgent needs to perform improvementof the equipment and 16 in Younggwang 1&3. The selected departments in one NPP are engineering, operation, electrical, mechanical, and instrumentation and control departments.(1) Present state of the maintenance in Korean nuclear power plantsIn Fig. 1, 75% of the respondents think that current selfsupporting level of maintenance technology in Korean NPP is high or very high and 22.6% think that it is in normal level. Only 2.4% of the respondents think that the technology is in low level. Fig. 2 shows the present state of maintenance in Korean NPP. In this figure, most of the maintenance related technologies are in high levels, except the system engineering. Most of the respondents think that the system engineering technology of Korean NPP is lower than other country.Etc., 6.8%Reactor coolant -cooldown and drain,0.068Reactor disassembly. 5.1%Diesel generator,0.153---Refueling, 32.2%LP turbine disassembly and testing, 13.6%Steam generator eddy current testing. -8.5% Replacement of RCP internal component, -0.034V Reactor assembly.3.4% Reactor coolant filling, vent and startup, 5.1%Fig. 4. Pressurized water reactor caseHelueling. 1.1%Replacement of RCP internal component,0.071Etc., 14.3%Diesel generator,0.071Steam generator eddy current testing.0.214LP turbine disassembly and testing. 42.9%Fig. 5. Pressurized heavy water reactor caseFig. 3 shows the urgent needs to perform improvement of the equipment. Most of the respondents replied that the group and manpower are very important for the equipment improvement. That is, the short of human resource is the most serious problem in the NPP maintenance work.(2) Present state of the preventive maintenanceIn this chapter, we investigate what is the problem to reduce the overhaul work during the overhaul. In the investigation, we divide the results into two cases; PWR case and PHWR case, because the type of nuclear power plant in Wolsung is PHWR from Canada, and the others are PWR from USA and France, and hence their operation environment and equipment are different. In the PWR case, as shown in Fig. 4, about 32.2% of respondents replied that refueling is the obstacle of the overhaul reduction. The fuel rods have been replaced during the overhaul of the plant, and most of the preventive maintenance has been performed during that time. But the one by one fuel rods replacement has taken lots of time, so that it makes the delay of the maintenance. Therefore, improvement of the refueling method is required. Next to that, the diesel generator maintenance, the low pressure turbine disassembly and testing are the obstacles of the overhaul reduction. Fig. 5 shows the PHWR case. In this figure, the low pressure turbine disassembly and testing, steam generator305eddy current testing are obstacle of the overhaul reduction. In comparison with PWR, PHWR can be refueled on-line; therefore refueling is not a serious problem in the reduction.Pohay 28?ala base, 28.69Cost analysis Lite0.31Management 22Fig. 6. Development of maintenance technology( Maintenance planning)Management 15,5%? ???? ?? 3Mondario: 14.3%Dlagnads/Evaluation69 0Fig. 7. Development of maintenance technology(Maintenance implementation)404Pettomanae baprovemen. 179%Component localization, 38.1%Saltenent of problem, 13.1%Countermeasurement of Aging, 26.2%Fig. 8. Development of maintenance technology(Equipment improvement)Nonnal. 4High0.105Very Fish 54.B%Fig. 9. Necessity of the predictive maintenancetechnology(3) Development of maintenance technologyIn Fig. 6, the respondents replied that database, policy, and management have to be developed for the maintenance planning. In Fig. 7, most of the respondent replied that the diagnosis and evaluation are important factors in the maintenance implementation. In means the analysis from lots of data is necessary to know abnormality of equipment and to support maintenance work. Fig. 8 shows that what is important in the equipment improvement. In the items, component localization is necessary for the improvement. As shown in Section 2, early Korean NPPs were imported from USA, France, and Canada. With the lapse of time, the components are no Longer manufactured by original equipment manufacturers or provided for spare parts support. Moreover, some manufacturers are no longer in business. Those issues make the maintenance work very difficult to perform. Hence, the localization is very important in the development of maintenance technology. The next one is he counter-measurement of system or component aging. This means that aging management is important in the equipment improvement related technologies. The result of the necessity of the predictive maintenance echnology is shown in Fig 9. In this figure, most of the respondents are aware of the importance of the predictive maintenance technology. With Fig. 7, it is strongly requested that the diagnosis and evaluation from condition nonitoring of the equipment are necessary for the operation and maintenance work in nuclear power plants.4) The demand for specific equipment maintenance echnologyCable 2 shows the demand for specific equipment naintenance technology. In the condition monitoring esults, main generator and turbine are necessary to monitor the abnormality by using vibration monitoring or -il analysis. In turbine, respondents replied that advancedon-destructive method is necessary to reduce the naintenance work. Condition monitoring is needed in theTable 2. The demand for specific equipmentmaintenance technology ConditionOn-line Monitoringmaintenance Main generator,Relay, Turbine,Pump, Equipment Steam generator, Diesel generator,Tube (PHWR) Reactor protection Transformersystem Non-destructive testing,Aging VibrationManagement, TechnologyLifecycle monitoring, Oil analysisManagement, ThermographyMonitoringransformer abnormality such as thermal aging, dielectric reakdown, or short circuit. Advanced oil testing and permography technology should be developed to detect bnormality. The tube maintenance in the steam generator mentioned among respondents from PHWR.the on-line maintenance results, respondents replied mat relay, pump, and diesel generator are necessary to erform the on-line maintenance. For that, advanced aging management and monitoring technologies should support ne maintenance work. In the reactor protection system, rift prediction and life cycle management technologies re needed to perform the on-line maintenance.- Summary and Conclusionthis study, we introduced the maintenance demand of PP in Korea. To investigate the demand, a questionnaire method is employed for the research. The questionnaire onsists of the present state of maintenance, the obstaclesoverhaul period reduction, the needs for development of Avanced maintenance technology, and the demand for pecific equipment maintenance technology. The uestionnaire results can be summarized as follows:-) Most of the respondents replied that current NPPaintenance technology is high except system engineering. -) Group and manpower are needed urgently to performe equipment improvement. -) In PWR, the refueling, LP turbine disassembly and sting are obstacles in the NPP overhaul period reduction. 1 PHWR, LP turbine disassembly and testing and steam enerator eddy current testing are obstacles in the eduction. +) Diagnosis, component localization, aging management e required in the development of maintenance chnology. -) The condition monitoring is necessary for main enerator, turbine, steam generator, and transformer. Relay, ump, diesel generator, and reactor protection system are eeded to perform the on-line maintenance.nis work has been supported by Korea Hydro & Nuclearwer Co., LTD through research contract. Special thanks e given to Korea Hydro & Nuclear Power Co., LTD.eferences ] L. Whistlecroft, D.J. Mallaburn, “Business aprovement and maintenance optimisation in Nuclear Lectric”, Power Station Maintenance - Profitability hrough Reliability, 1998. First IEE/IMechE International onference on (Conf. Publ. No. 452), 30 March-1 April98, pp. 179-183. ] S.S. Darling, D.A. Army, T. P. Mairs, “Improving plant pacity by redefining the processes by which aintenance is planned, scheduled, and accomplished”, uclear Science Symposium and Medical Imaging onference, 1994 IEEE Conference Record Volume 3,Oct.-5 Nov. 1994, pp. 1051-1055. ] ““Nuclear Power in South Korea”, World Nuclear ssociation, May 2005.“ “A Survey on the Maintenance Demand of Nuclear Power Plants in Korea“ “Jun Seok LEE,Poong Hyun SEONG,Chang Heui JANG,Hyuk Soon LIM,Jang Hwan NA,Seong Jong OH
Section 5, we present summary and conclusion from the questionnaire result.1. IntroductionRecently, most of NPP companies have been targeting several areas to improve their productivity actively. Improving availability of the plant, shorter outages and a significantly lower reactor trip had all contributed to higher output of the plant. However, there is a limit in the improvement to gain higher output. For that reason, they have been considering the improvement of maintenance work [1], [2]. The object of this research is to do preliminary investigation of the NPP maintenance technology development. For the work, it is necessary to know the current maintenance environment in Korean NPPs. Also, it is very important to get the plant operators and staffs’ opinions for the research. To get their opinion, we carried out the questionnaire investigation. The structure of this paper is as follows. In Section 2, we introduce the present state of Korean NPPs. The questionnaire contents are introduced in Section 3. The result of the questionnaire is presented in Section 4. InPOC: 373-1 Guseong-Dong, Yuseong-Gu, Daejeon, Korea 305-701, Center for Advanced Reactor Research, Korea Advanced Institute of Science and Technology, Tel: +82-42-869-3860, Fax: +82-42-869-3849, e-mail: wahrheit@kaist.ac.kr d of Nuclear Power Plants in Koreaearch, Korea Advanced Institute of Science andand Quantum Engineering, Korea Advanced\uantum Engineering, Korea Advanced InstituteC....del N..len. Dawa2. Nuclear power plants in KoreaTable 1 shows the NPP sites in South Korea [3]. South Korea has 4 sites and 20 commercial nuclear power plants. The first three commercial units - Kori 1 & 2 and Wolsong-1, were bought as turnkey projects. The next six, Kori 3 & 4, Yonggwang 1 & 2, Ulchin 1 & 2, comprised the country's second generation of plants and involved local contractors and manufacturers. At that stage the country had six Pressurized Water Reactor (PWR) units derived from Combustion Engineering in USA, two from Framatome in Europe and one from AECL in Canada of radically different design. Then, in the mid 1980s, the Korean nuclear industry begins a plan to standardize the design of NPPs and to achieve much greater self-sufficiency in building. In 1987, the industry entered a ten-year technology transfer program with Combustion Engineering (now Westinghouse) to achieve technical self-reliance, and this was extended in 1997. A sidetrack from this was the ordering of three more CANDU-6 Pressurized Heavy Water Reactor (PHWR)303TypeTable 1. Power reactors operating in Korea Name ReactorOperation PWR1978/04/01PWR Kori7/83 PWR9/85 PWR4/86 PWR9788 PWR9789 PWR1998/06/01(KSNP) UlchinPWR6/99 (KSNP) PWR1/04 (KSNP) PWR12/04 (KSNP) PHWR4783PHWR Woisong6/97 PHWR6/98 PHWR6/99 PWR8/86 PWR6/87 PWR0.126315789473684(Syst 80) YonggwangPWR3/96 (Syst 80) PWR5/02 (KSNP) PWR6(KSNP) units from AECL in Canada, to complete the Wolsong power plant. These units were built with substantial local input and were commissioned from 1997 to 1999. In 1987 the industry selected the CE System 80 steam supply system as the basis of standardization. Yonggwang 3&4 were the first to use this, with great success. A further step in standardization was the Korean Standard Nuclear Plant (KSNP), which from 1984 brought in some further CE System 80 features and incorporated many of the US Advanced Light Water Reactor design requirements.3. Questionnaire for the researchThe questionnaire for the survey is classified to 4 parts.(1) Present state of the maintenance in Korean nuclear power plant In this chapter, we survey on Korea Hydro & Nuclear Power Co., LTD. operators and staffs' opinion of the current state of maintenance. The contents for this chapter are the self-supporting level and the level of the maintenance technology in Korean NPPs in comparison with other countries. The maintenance technology items are classified into 5 items:? Management technology: The technology related to theequipment failure prevention, and maintaining the equipment in optimum condition. For example,improvement of operating method, environment, etc. Prediction of the equipment failure and condition monitoring technology: The testing, diagnosis, and evaluation technology for the equipment failureprediction and detection. ? Repair technology: Equipment assembly, disassembly,and replacement technology. ? System engineering technology: The technology toimprove existing equipment's performance,reliability, and safety. ? Integrated maintenance management technology: Themanagement technology to reduce operation and maintenance cost and maximize its effect.The answers for those questions are “very low““, ““low”, ““normal““, ““high”, and “very high”. The urgent needs to perform improvement of the equipment are inquired in the last of this chapter.(2) Present state of the preventive maintenance In this chapter, we want to know the obstacle of the overhaul period reduction. In the analysis, we divided the result into 2 cases; PWR case and PHWR case.(3) Development maintenance technology This chapter shows the technologies which are needed in the current maintenance work. The technologies are classified into 3 contents - maintenance planning, implementation, and equipment improvement. In the last part of this chapter, the degree of necessity of the predictive maintenance technology is inquired. Most of NPPs perform the preventive maintenance. However, it is found that many NPP maintenance staffs think that some maintenance resources are wasted and some activities are not needed. In addition, they think that some equipments can be in worse conditions after performing preventive maintenance. Therefore, equipment condition based predictive maintenance is needed to be considered in NPP industry to optimize the reliability and the availability of equipments.(4) The demand for specific equipment maintenance technology This chapter shows the specific system or components which are needed for the maintenance technology of the specific system, structure and component in NPPs in terms of the condition monitoring, on-line maintenance, and shortening of the overhaul.4. ResultWe carried out a survey on 86 operators and staffs in 8 units; 13 in Kori 2, 32 in Ulchin 1-3, 23 in Wolsung 1&2,304Vesy ft0.339Noernal, 22:6%Hch53.1Fig. 1. Self-supporting levelIntegrated maintenancemanagementSystem engineeringRepairPrediction of equipment failure and conditionmonitoringMaintenance management0.20.6ma Very High Bros a Noa Down Veay LoveFig. 2. Present state of nuclear power plantmaintenancePOCotcomsexnert for bialyse 57%interest of manager2.14Ersun and manpower. 59.5Fig. 3. The urgent needs to perform improvementof the equipment and 16 in Younggwang 1&3. The selected departments in one NPP are engineering, operation, electrical, mechanical, and instrumentation and control departments.(1) Present state of the maintenance in Korean nuclear power plantsIn Fig. 1, 75% of the respondents think that current selfsupporting level of maintenance technology in Korean NPP is high or very high and 22.6% think that it is in normal level. Only 2.4% of the respondents think that the technology is in low level. Fig. 2 shows the present state of maintenance in Korean NPP. In this figure, most of the maintenance related technologies are in high levels, except the system engineering. Most of the respondents think that the system engineering technology of Korean NPP is lower than other country.Etc., 6.8%Reactor coolant -cooldown and drain,0.068Reactor disassembly. 5.1%Diesel generator,0.153---Refueling, 32.2%LP turbine disassembly and testing, 13.6%Steam generator eddy current testing. -8.5% Replacement of RCP internal component, -0.034V Reactor assembly.3.4% Reactor coolant filling, vent and startup, 5.1%Fig. 4. Pressurized water reactor caseHelueling. 1.1%Replacement of RCP internal component,0.071Etc., 14.3%Diesel generator,0.071Steam generator eddy current testing.0.214LP turbine disassembly and testing. 42.9%Fig. 5. Pressurized heavy water reactor caseFig. 3 shows the urgent needs to perform improvement of the equipment. Most of the respondents replied that the group and manpower are very important for the equipment improvement. That is, the short of human resource is the most serious problem in the NPP maintenance work.(2) Present state of the preventive maintenanceIn this chapter, we investigate what is the problem to reduce the overhaul work during the overhaul. In the investigation, we divide the results into two cases; PWR case and PHWR case, because the type of nuclear power plant in Wolsung is PHWR from Canada, and the others are PWR from USA and France, and hence their operation environment and equipment are different. In the PWR case, as shown in Fig. 4, about 32.2% of respondents replied that refueling is the obstacle of the overhaul reduction. The fuel rods have been replaced during the overhaul of the plant, and most of the preventive maintenance has been performed during that time. But the one by one fuel rods replacement has taken lots of time, so that it makes the delay of the maintenance. Therefore, improvement of the refueling method is required. Next to that, the diesel generator maintenance, the low pressure turbine disassembly and testing are the obstacles of the overhaul reduction. Fig. 5 shows the PHWR case. In this figure, the low pressure turbine disassembly and testing, steam generator305eddy current testing are obstacle of the overhaul reduction. In comparison with PWR, PHWR can be refueled on-line; therefore refueling is not a serious problem in the reduction.Pohay 28?ala base, 28.69Cost analysis Lite0.31Management 22Fig. 6. Development of maintenance technology( Maintenance planning)Management 15,5%? ???? ?? 3Mondario: 14.3%Dlagnads/Evaluation69 0Fig. 7. Development of maintenance technology(Maintenance implementation)404Pettomanae baprovemen. 179%Component localization, 38.1%Saltenent of problem, 13.1%Countermeasurement of Aging, 26.2%Fig. 8. Development of maintenance technology(Equipment improvement)Nonnal. 4High0.105Very Fish 54.B%Fig. 9. Necessity of the predictive maintenancetechnology(3) Development of maintenance technologyIn Fig. 6, the respondents replied that database, policy, and management have to be developed for the maintenance planning. In Fig. 7, most of the respondent replied that the diagnosis and evaluation are important factors in the maintenance implementation. In means the analysis from lots of data is necessary to know abnormality of equipment and to support maintenance work. Fig. 8 shows that what is important in the equipment improvement. In the items, component localization is necessary for the improvement. As shown in Section 2, early Korean NPPs were imported from USA, France, and Canada. With the lapse of time, the components are no Longer manufactured by original equipment manufacturers or provided for spare parts support. Moreover, some manufacturers are no longer in business. Those issues make the maintenance work very difficult to perform. Hence, the localization is very important in the development of maintenance technology. The next one is he counter-measurement of system or component aging. This means that aging management is important in the equipment improvement related technologies. The result of the necessity of the predictive maintenance echnology is shown in Fig 9. In this figure, most of the respondents are aware of the importance of the predictive maintenance technology. With Fig. 7, it is strongly requested that the diagnosis and evaluation from condition nonitoring of the equipment are necessary for the operation and maintenance work in nuclear power plants.4) The demand for specific equipment maintenance echnologyCable 2 shows the demand for specific equipment naintenance technology. In the condition monitoring esults, main generator and turbine are necessary to monitor the abnormality by using vibration monitoring or -il analysis. In turbine, respondents replied that advancedon-destructive method is necessary to reduce the naintenance work. Condition monitoring is needed in theTable 2. The demand for specific equipmentmaintenance technology ConditionOn-line Monitoringmaintenance Main generator,Relay, Turbine,Pump, Equipment Steam generator, Diesel generator,Tube (PHWR) Reactor protection Transformersystem Non-destructive testing,Aging VibrationManagement, TechnologyLifecycle monitoring, Oil analysisManagement, ThermographyMonitoringransformer abnormality such as thermal aging, dielectric reakdown, or short circuit. Advanced oil testing and permography technology should be developed to detect bnormality. The tube maintenance in the steam generator mentioned among respondents from PHWR.the on-line maintenance results, respondents replied mat relay, pump, and diesel generator are necessary to erform the on-line maintenance. For that, advanced aging management and monitoring technologies should support ne maintenance work. In the reactor protection system, rift prediction and life cycle management technologies re needed to perform the on-line maintenance.- Summary and Conclusionthis study, we introduced the maintenance demand of PP in Korea. To investigate the demand, a questionnaire method is employed for the research. The questionnaire onsists of the present state of maintenance, the obstaclesoverhaul period reduction, the needs for development of Avanced maintenance technology, and the demand for pecific equipment maintenance technology. The uestionnaire results can be summarized as follows:-) Most of the respondents replied that current NPPaintenance technology is high except system engineering. -) Group and manpower are needed urgently to performe equipment improvement. -) In PWR, the refueling, LP turbine disassembly and sting are obstacles in the NPP overhaul period reduction. 1 PHWR, LP turbine disassembly and testing and steam enerator eddy current testing are obstacles in the eduction. +) Diagnosis, component localization, aging management e required in the development of maintenance chnology. -) The condition monitoring is necessary for main enerator, turbine, steam generator, and transformer. Relay, ump, diesel generator, and reactor protection system are eeded to perform the on-line maintenance.nis work has been supported by Korea Hydro & Nuclearwer Co., LTD through research contract. Special thanks e given to Korea Hydro & Nuclear Power Co., LTD.eferences ] L. Whistlecroft, D.J. Mallaburn, “Business aprovement and maintenance optimisation in Nuclear Lectric”, Power Station Maintenance - Profitability hrough Reliability, 1998. First IEE/IMechE International onference on (Conf. Publ. No. 452), 30 March-1 April98, pp. 179-183. ] S.S. Darling, D.A. Army, T. P. Mairs, “Improving plant pacity by redefining the processes by which aintenance is planned, scheduled, and accomplished”, uclear Science Symposium and Medical Imaging onference, 1994 IEEE Conference Record Volume 3,Oct.-5 Nov. 1994, pp. 1051-1055. ] ““Nuclear Power in South Korea”, World Nuclear ssociation, May 2005.“ “A Survey on the Maintenance Demand of Nuclear Power Plants in Korea“ “Jun Seok LEE,Poong Hyun SEONG,Chang Heui JANG,Hyuk Soon LIM,Jang Hwan NA,Seong Jong OH