Semiconductor Wear Out at Nuclear Power Plants

2000 ◽  
Author(s):  
James B. Riddle
Keyword(s):  
Failure Analysis ◽  
Case Studies ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Light Output ◽  
Analysis Techniques ◽  
Root Cause ◽  
Corrective Actions ◽  
Control Circuits

Abstract This paper will examine semiconductor wear out at San Onofre Nuclear Generation Station (SONGS). The topics will include case studies, failure mechanisms, diagnostic techniques, failure analysis techniques and root cause corrective actions. Nuclear power plants are unique in that instrumentation and control circuits are continuously energized, are periodically tested, and have been in operation for greater than 25 years. Root cause evaluations at SONGS have identified numerous semiconductor failures due to wear out. Case studies include light output deterioration in opto-isolators, junction alloying failures of transistors and integrated circuits and parametric shifts in operational amplifiers. In most cases the devices do not fail catastrophically but degraded to the point of circuit level functional failure. Failure analysis techniques include circuit analysis, board level troubleshooting to identify the degraded components. Intermittent failures require power cycling, thermal cycling, and long term monitoring to identify the responsible components. Corrective actions for semiconductor wear out at SONGS include enhanced monitoring and proactive change out of identified part types.

Corrosion Cause Analysis of Electric Feedwater Pump Motor Shaft in Nuclear Power Plants and Relevant Corrective Actions

2017 ◽  
Author(s):  
Che Yinhui ◽  
Guan Jianjun ◽  
Zu Shuai ◽  
Chen Qiang
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Economic Benefits ◽  
Motor Shaft ◽  
Cause Analysis ◽  
Root Cause ◽  
Feedwater Pump ◽  
Corrective Actions

Electric feedwater pump is an important feedwater equipment of nuclear power plants, and its reliability is directly related to the safe and steady operation of nuclear power plants and also economic benefits. In fact, corrosion of electric feedwater pump motor shaft occurs repeatedly, and even bearing shell in the motor can be burned out happen sometimes. This text sets out to analyze the cause of corrosion of electric feedwater pump motor shaft, identify the root cause, and further work out pertinent corrective actions based on the structure of the feedwater pump.

scholarly journals State-of-the-Art Water Treatment in Czech Power Sector: Industry-Proven Case Studies Showing Economic and Technical Benefits of Membrane and Other Novel Technologies for Each Particular Water Cycle

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 98
Author(s):  
Jaromír Marek
Keyword(s):  
Water Treatment ◽  
Case Studies ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Water Cycle ◽  
Liquid Waste ◽  
Novel Technologies ◽  
Turbine Condensate ◽  
Common Cycles

The article first summarizes case studies on the three basic types of treated water used in power plants and heating stations. Its main focus is Czechia as the representative of Eastern European countries. Water as the working medium in the power industry presents the three most common cycles—the first is make-up water for boilers, the second is cooling water and the third is represented by a specific type of water (e.g., liquid waste mixtures, primary and secondary circuits in nuclear power plants, turbine condensate, etc.). The water treatment technologies can be summarized into four main groups—(1) filtration (coagulation) and dosing chemicals, (2) ion exchange technology, (3) membrane processes and (4) a combination of the last two. The article shows the ideal industry-proven technology for each water cycle. Case studies revealed the economic, technical and environmental advantages/disadvantages of each technology. The percentage of technologies operated in energetics in Eastern Europe is briefly described. Although the work is conceived as an overview of water treatment in real operation, its novelty lies in a technological model of the treatment of turbine condensate, recycling of the cooling tower blowdown plus other liquid waste mixtures, and the rejection of colloidal substances from the secondary circuit in nuclear power plants. This is followed by an evaluation of the potential novel technologies and novel materials.

Nonlinear analysis techniques of block masonry walls in nuclear power plants

1986 ◽  
Vol 91 (1) ◽  
pp. 13-16
Author(s):  
Ahmad A. Hamid ◽  
Harry G. Harris ◽  
Vu N. Con ◽  
Nilesh C. Chokshi
Keyword(s):  
Nonlinear Analysis ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Masonry Walls ◽  
Analysis Techniques

scholarly journals Case Studies on the Decommissioning of Nuclear Power Plants and Radioactive Waste Repository Abroad

2019 ◽  
Vol 19 (4) ◽  
pp. 151-156
Author(s):  
Namjin Cho ◽  
Dongsu Im ◽  
Hyunwook Bang ◽  
Teayeon Cho ◽  
Junglim Lee
Keyword(s):  
Radioactive Waste ◽  
Case Studies ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Radioactive Waste Repository ◽  
Waste Repository

scholarly journals Staffing decision processes and issues: Case studies of seven US Nuclear Power Plants

1994 ◽  
Author(s):  
B. Melber ◽  
A. Roussel ◽  
K. Baker ◽  
N. Durbin ◽  
P. Hunt ◽  
...  
Keyword(s):  
Case Studies ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Decision Processes

A New Eddy Current 3-D Profilometry for a Quantitative Measurement of Geometric Anomaly in Steam Generator Tubes of Nuclear Power Plants

2006 ◽  
Vol 321-323 ◽  
pp. 426-429
Author(s):  
Deok Hyun Lee ◽  
Myung Sik Choi ◽  
Do Haeng Hur ◽  
Jung Ho Han ◽  
Myung Ho Song ◽  
...  
Keyword(s):  
Steam Generator ◽  
Eddy Current ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Three Dimensional ◽  
Accurate Information ◽  
Profile Measurement ◽  
Root Cause ◽  
Steam Generator Tubes

Most of the corrosive degradations in steam generator tubes of nuclear power plants are closely related to the residual stress existing in the local region of a geometric change, that is, an expansion transition, u-bend, ding, dent, bulge, etc. Therefore, accurate information on a geometric anomaly in a tube is a prerequisite to the activity of a non destructive inspection for a precise and earlier detection of a defect in order to prevent a failure during an operation, and also for a root cause analysis of a failure. In this paper, a newly developed eddy current technique of a three-dimensional profilometry is introduced and the proof for the applicability of the technique to a plant inspection is provided. The quantitative profile measurement using a new eddy current probe was performed on steam generator expansion mock-up tubes with various geometric anomalies typically observed in the operating power plants, and the accuracy of the measured data was compared with those from the laser profilometry.

scholarly journals Fire Safety in Nuclear Power Plants: A Risk-Informed and Performance-Based Approach

1999 ◽  
Author(s):  
Mohamed A. Azarm ◽  
Richard J. Travis
Keyword(s):  
Case Studies ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Fire Risk ◽  
Policy And Practice ◽  
Fire Risk Analysis ◽  
Regulatory Decision ◽  
Near Term ◽  
And Performance

Abstract The consideration of risk in regulatory decision-making has long been a part of NRC’s policy and practice. Initially, these considerations were qualitative and were based on risk insights. The early regulations relied on good practices, past insights, and accepted standards. As a result, most NRC regulations were prescriptive and were applied uniformly to all areas within the regulatory scope. Risk technology is changing regulations by prioritizing the areas within regulatory scope based on risk, thereby focusing on the risk-important areas. Performance technology, on the other hand, is changing the regulations by allowing requirements to be adjusted based on the specific performance expected and manifested, rather than a prior prescriptive requirement. Consistent with the objectives of risk-informed and performance-based regulatory requirements, BNL evaluated the feasibility of applying risk- and performance-technologies to modifying NRC’s current regulations on fire protection for nuclear power plants.(1) This feasibility study entailed several case studies (trial applications). This paper describes the results of two of them. Besides the case studies, the paper discusses an overall evaluation of methodologies for fire-risk analysis to support the risk-informed regulation. It identifies some current shortcomings and proposes some near-term solutions.

Root Cause Analysis of Pipeline Rupture in the Condensate Extraction System of Nuclear Power Plant

2017 ◽  
Author(s):  
Chen Qiang ◽  
Han Ning ◽  
Chen Weihan ◽  
Che Yinhui
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Root Cause Analysis ◽  
Extraction System ◽  
Stable Operation ◽  
Pressurized Water ◽  
High Oxygen Content ◽  
Cause Analysis ◽  
Root Cause

Pipe rupture in the Condensate Extraction system (CEX) of nuclear power plants will lead to high oxygen content in the secondary circuit and therefore exacerbates equipment and pipeline corrosion. At the same time, there is a risk of loss of vacuum in the system, which has a direct impact on the safe and stable operation of nuclear power plants and will affect the economic benefits. In this paper, Equipment Failure Root Cause Analysis (ERCA) methodology is employed combined with metallography analysis (SEM analysis, XRD) and finite element simulation analysis, to investigate the root cause for drainage pipeline rupture in CEX System of Pressurized Water Reactor (PWR). Detailed analysis process of ERCA was introduced including RCA project establishment, data collection, failure modes analysis and so on. The most probable failure mode is pointed out through the investigation and evidence analyzed. It suggests that the improper design and the installation of limiting orifice plate should be the root cause. And corresponding corrective actions are put forward in details to prevent the recurrence.

The Problems of Nuclear Power are Much Too Serious to Leave to Nuclear Experts

1998 ◽  
Vol 42 (10) ◽  
pp. 737-739 ◽  
Author(s):  
Vladimir Munipov
Keyword(s):  
Operating Procedure ◽  
Chernobyl Accident ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Protection System ◽  
Root Cause ◽  
Nuclear Age ◽  
Plant Personnel ◽  
Machine Interaction

The full story of the Chernobyl disaster is yet to be disclosed. The initial cause of the accident was a very unlikely violation of the operating procedure and conditions by the plant personnel which showed the design faults of the reactor and the control and protection system rods. The main or root cause of the accident was the inadequate design of the user-machine interaction. Many people involved with the reliability and safety of Nuclear Power Plants now believe that even if the operators had acted correctly their actions would have resulted in the explosion. The main lesson from the Chernobyl accident is that the Nuclear Age calls for a new culture and and can certainly not tolerate ignorance. Chernobyl is a severe warning of what can happen if people disregard the necessity of including ergonomics in the process of designing and operating complex technical facilities.

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