Day Two (July 14, 2010)
[A-2] Nondestructive Evaluation (NDE)
[B-1] Poster Session and Shotgun Presentation
[B-2] Maintenance Optimization
[C-1] Pipe Wall Thinning – its Management and Measurement
[C-2] Prototype Fast Breeder Reactor (FBR) Monju
[E-1] Maintenance Sociology (Part I "Community Relations")
[E-2] International Session
[E-3] Industry-academic Collaboration (Part I) - Needs and Case Studies
[F-3] EJAM Session
Various contexts from on maintenance optimization in NPPs and thermal power plants, to on the influence by noises to maintenance personnel were introduced.
- B-2-1
- Study on how to evaluate the effectiveness of maintenance activities for giant complex plant system
Abstract
If we try to check the effectiveness of maintenance activities in nuclear power plant, it is necessary to evaluate plant performance from the viewpoint of nuclear safety and economy. So, in this paper, after the relation among maintenance optimization, maintenance performance targets, maintenance effectiveness indicator and maintenance key parameters important to nuclear safety and economy was made clear, a method to evaluate the effectiveness of maintenance activities was discussed. As a result of consideration, it was concluded that the maintenance effectiveness indicator proposed in this paper can evaluate maintenance effectiveness and can show the direction of improving existing maintenance program because the relation with maintenance performance target and maintenance key parameters is clear.
Keywords
Maintenance Cycle, Maintenance Optimization, Performance Indicator, Maintenance Performance Target, Maintenance Effectiveness, Maintenance Importance
- B-2-2
- System reliability comparison for operating state from both Generation Loss and Core Damage Frequency
Abstract
Recently, Introduction of the use of risk information into safety related activities in nuclear power plants is being discussed by electric power companies and others. Then, as an example of "Use of Risk information", Reliability comparisons of Motor-Generator set and Variable Voltage Variable Frequency for Primary Loop Recirculation System (PLR) are simply evaluated from both Generation Loss and Core Damage Frequency (CDF) using Probabilistic Safety Assessment (PSA) in this study.
Keywords
Probabilistic Safety Assessment (PSA), Generation Risk Assessment (GRA), Core Damage Frequency (CDF), Primary Loop Recirculation System (PLR)
- B-2-3
- Overview of the technical evaluation of 40-year Plant Life Management Tsuruga Power Station unit 1
Abstract
Japan Atomic Power Company (JAPC) has completed the Ageing Management Technical Evaluation (AMTE) for Tsuruga Power Station unit 1 that has entered 40-year operation first in Japan, and has established the long-term maintenance management policy based on the evaluation.
JAPC conducted the AMTE in accordance with "Ageing Management Implementation Guideline for Nuclear Power Plants", "Code on Implementation and review of Nuclear Power Plant Ageing Management Programs 2008" etc. During the 40-years AMTE, the verification of the 30 years AMTE results was also performed as an additional evaluation to 30 years AMTE.
The AMTE of Tsuruga Power Station unit 1 concluded that most of component and structure would be maintained their integrity by continued existing preservation activities, even assuming the operation period of 60 years.
For some components, JAPC identified additional maintenance activities to be implemented after 40 years operation as a part of the long term maintenance policy. These activities will be reflected in maintenance plan and implemented, which assure the integrity of these component.
Keywords
PLM, Ageing management technical evaluation (AMTE), 40-year, Tsuruga, JAPC
- B-2-4
- Approaches to extend operating cycle of Hamaoka Unit 3
Abstract
The new regulatory requirements for inspections at nuclear power station took effect in January 2009, which require utilities to enhance an optimization of maintenance programs. At the same time, this regulatory change made it possible for utilities to apply for an extension of the operating cycle of a plant from 13 months of previous regulatory limit up to 24 months.
In this paper, approaches to extend operating cycle of Hamaoka Unit 3 are described.
Keywords
New Nuclear Inspection System, Maintenance activities, Technical Assessment, Hamaoka Unit 3
- B-2-5
- Preliminary Evaluation Results on the Effects of Power Uprate upon Maintenance Activities
Abstract
The Japan Atomic Power Company (JAPC) plans to increase rated reactor thermal power of Tokai No.2 Power
Station (Tokai-2) by five percent. This paper describes preliminary evaluation results on the effects of
five-percent power uprate in Tokai-2 upon its maintenance activities.
Keywords
Tokai-2, Power Uprate, Aging degradation Mechanism, Plant Life Management, Maintenance Activity
- B-2-6
- The Reflection of Operation and Maintenance Experience to the First Advanced PWR Design
Abstract
Tsuruga Unit 3&4 is the first APWR, which introduces a lot of improved technology aiming at safety, reliability and operability enhancement. This paper explains about our activities as to the reflection of our operation and maintenance experience including countermeasures against experienced troubles and plant life management evaluation result of operating PWRs in Japan. And the preparation for maintenance program introduction and basic policy for training of future operators and maintenance engineers are also described briefly.
Keywords
Advanced PWR, Tsuruga unit 3&4, Reflection of Operation and Maintenance Experience
- B-2-7
- Research and Evaluation of New Technologies to Improve the Maintenance of Pipeline for Gas Distribution toward the Next Generation
Abstract
The aim of this study is to research and evaluate new technologies in the world from the point of view to improve the safety and security of pipeline for gas distribution toward the next generation which can practice the productive maintenance and preventive maintenance.
Keywords
Maintenance, Pipeline, Gas Distribution, New technologies
- B-2-8
- Establishment of an In-House Technique for Maintaining Circuit Breakers Used in Aging Power Plants
Abstract
In a thermal power plant that has been operating for more than 30 years, approximately 1100 MBBs and ACBs are used. However, since the supply of substitution parts from the breaker manufacturer stopped in 2005 and maintenance has become difficult, Chubu Electric has established an in-house maintenance technique through technical collaboration with its group company Chubu Plant Service Co., Ltd., in order for the company to be independent of the manufacturer.
Keywords
Establishment of an In-House Technique
- B-2-9
- High noise effects on engineers' sound perception: improving listening capabilities in noisy environments
Abstract
In a ship’s engine room, engineers are surrounded by various noises emitted from the diesel engine, generator, pumps, and other auxiliary machines. During inspections and activities in such environments, workers strive to listen for extraordinary noises issuing from machines and instruments, which might signal a need for maintenance work. If that practice functions well, proper noise perception helps them perform maintenance work and achieve early detection of abnormalities that would otherwise contribute to ship accidents.
We specifically examined the listening capabilities used to detect extraordinary noises in noisy conditions such as those in engine rooms. This study investigated natural human capabilities and administered a questionnaire survey of machine room workers. Examinees were asked to tell the direction from which a certain sound came. Fewer questions were answered correctly in noisy conditions: 20% fewer than with no background noise. Results underscore the difficulty of discerning the correct direction from whence sound comes, signaling a deficit of hearing sensitivity. We propose a support system to improve acoustic sensing in noisy conditions. The system’s performance was evaluated, revealing a definite improvement in perception of sound information in noisy conditions at around 100 dB, which are typical of a diesel engine room.
Keywords
noisy environments ,direction, listening capabilities
- B-2-10
- Arrest of SCC, Fatigue and Hydrogen Assisted Cracks, and Make Harmless the Cracks by Overload
Abstract
This study proposes an innovative method for arresting SCC, fatigue and hydrogen assisted cracks, and making harmless the cracks by overload. By overloading, compressive residual stress is introduced ahead of the crack. The residual stress reduce K values and arrest the crack. By theory, K1SCC, K1HE and ⊿Kth increase with increasing Kov (K value by overload) and the nominal threshold values were given the equation: NK1SCC, NK1HE and ⊿NKth=C + DKov. Where C is K1SCC, K1HE and ⊿Kth, respectively、and D is a proportional constant and 0.24 ~0.27. Experimental results showed that D showed good agreement with theory, except SUS316 steel by SCC. The reason was assumed that SCC test time for K1SCC definition was not enough but shorter. If threshold vales are enough larger than applied K and ⊿K values, crack is able to grow and can be made harmless.
Keywords
Overload Effect, SCC, Fatigue, Hydrogen Assisted Crack, Crack Arrest, Make Crack Harmless
- B-2-11
- Maintenance activities in Chemical Processing Facility
1. Renewal of driving unit of negative pressure control valves
Abstract
The negative pressure control valve is reliable apparatus which has been used in many nuclear facilities. In recent years, there are some troubles on those valves in CPF (Chemical Processing Facility) by the aged deterioration because the valves were kept using for more than 25 years after facility had operated. Therefore, we have been carrying out renewal of driving units of the valves to assure performance of negative pressure control function and to keep stability of operation of the facility. In this presentation, we report knowledge provided through the renewal work, such as the renewal procedure, the deterioration situation of components and the cause of troubles.
Keywords
Chemical Processing Facility, aged deterioration, negative pressure control valve
- B-2-12
- The lube oil leakage from indicator valves of Emergency Diesel Generator
Abstract
The lube oil leakage from indicator valves of Emergency Diesel Generator was found at Shika nuclear power plant Unit 2 in Dec. 2009.
As a result of investigation, we found that temperature fall after shutdown of diesel engine generate negative pressure in the combustion chamber, and the cooling oil for piston leak into the combustion chamber through the oil-drain port of piston by this negative pressure.
Keywords
Emergency Diesel Generator,Diesel engine
- B-2-13
- Study of Degradation of Off-Gas H2/O2 Recombination Catalyst at Hamaoka Unit 4 and 5
Abstract
By evaluating the phenomena that hydrogen concentration of outlet gas in the off-gas treatment system at Hamaoka Unit 4 and 5 had increased, it was concluded that the causes of the phenomena were transformation of support alumina by alteration of manufacturing process of catalysts and the deactivation by catalyst poisoning material. Therefore, the manufacturing process was modified and the poisoning material was identified and removed. Moreover, developments such as catalyzer performance monitoring technology with thermometers have been continued in order to improve the reliability of the system.
Keywords
Catalyst, Off-Gas System, Recombiner Degradation, Boehmite, Organic Silicon
- B-2-14
- The construction of an intensive monitoring system for power supply stations in the Tokai Reprocessing Plant
Abstract
There are plural facilities having a radiation controlled area in the Tokai reprocessing plant, and an uninterruptible power supply system which considered a blackout is necessary for the power supply to each facility from the viewpoint of radiological management and nuclear material containment. In addition, at the time of the power supplying abnormality, intelligence gathering is necessary for prompt measures and restoration. In this report, the intensive monitoring system, which aimed for the unification of the power supply monitor place and the acceleration of the intelligence gathering to detect a power supply abnormality point, is described.
Keywords
uninterruptible power supply, intensive monitoring system, reprocessing plant
- B-2-15
- Optimization of the exchange period of high efficiency particulate air filter in Tokai Reprocessing Plant
Abstract
In the ventilation facilities of the Tokai reprocessing plant, particle filters are generally installed both in air-intake and exhaust systems. In the air-intake system, atmospheric dust is filtered and the cleaned air is supplied into radiation controlled areas, whereas in the exhaust system, radioactive materials are filtered and it is discharged to the environment. Because the filter of the exhaust system serves to prevent radiological release to the environment, a high-efficiency particle air (HEPA) filter that a decontamination factor is extremely high, is used for filtering radioactive particles. The HEPA filter is usually exchanged with new one when the filter is carried over with particles, or it is exchanged by the limit as an anti-aging deterioration measure in time.
This report reviews the exchange period of a particle filter by confirming the integrity of a filter installed in investigation and the enforcement of the past filter exchange results and reports the result that planned adequacy.
Keywords
Tokai Reprocessing Plant, ventilation facilities, HEPA filter, exchange period
- B-2-16
- Application RiskWatcher to Japanese PWR
Abstract
On-Line-Maintenance (OLM) of NPP is under discussion for introduction of in Japan. Risk monitor is a real-time risk analysis tool used to determine the point-in-time risk based on the actual plant configuration, which assess increase in risk that may result from OLM activities. MHI adopted RiskWatcherTM provided by Swedish company Scandpower as risk monitor software and is developing it for Japanese utilities application. By Inputting PSA model into RiskWatcherTM, the risk-monitor is made up. It can calculate the risk level (Core Damage Frequency and Containment Failure Frequency), importance factors, and Defence-in-Depth of NPP at a short time so that it may contribute effective planning schedule of OLM.
Keywords
Living PSA, risk monitor, RiskWacher, Riskspectrum, On-Line-Maintenance
Fig. 8 A presentation on [B-2] "Maintenance Optimization"
Proceedings of JSM 7th Annual Conference, p.121-p.183, Omaezaki, July 2010 (in Japanese).