Ultrasonic Inspection of Electrofusion Joints of Large Polyethylene Pipes in Nuclear Power Plants

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Jinyang Zheng ◽  
Dongsheng Hou ◽  
Weican Guo ◽  
Xiaoming Miao ◽  
Yaoda Zhou ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Ultrasonic Inspection ◽  
Cooling Water ◽  
Operating Pressure ◽  
Hdpe Pipe ◽  
Hdpe Pipes

High-density polyethylene (HDPE) pipe has many advantages such as good flexibility, corrosion resistance, and long service life. It has been introduced into nuclear power plants for transportation of cooling water in U.S. and Europe. Recently, four HDPE pipelines (PE4710) were used in essential cooling water system with operating pressure of 0.6 MPa and operating temperature of no more than 60 °C in a newly established AP1000 nuclear power plant in Zhejiang, China. The outside diameter and thickness are 30 in. and 3.3 in., respectively, which are much larger and thicker than traditional HDPE pipe for natural gas. This brought forward a challenge for nondestructive testing (NDT) and safety assessment of such pipes. In this paper, a solution for inspecting electrofusion (EF) joints of thick-walled HDPE pipes is presented, and the results of an on-site inspection of the nuclear power plant are revealed. To expand the thickness up-limit of previously developed ultrasonic-phased array instrument, an optimization method was proposed by calculating weighing effects of different testing parameters and introducing the concept of overall performance according to practical requirement, by comprehensively considering sensitivity, penetration, signal-to-noise ratio (SNR), resolution, and accuracy. Typical defects were found in field inspection. The result shows that the presented technique is capable of inspecting EF joints for connecting large-size HDPE pipes used in nuclear power plants.

Ultrasonic Inspection of Large Diameter Polyethylene Pipe Used in Nuclear Power Plant

2014 ◽  
Author(s):  
Jianfeng Shi ◽  
Dongsheng Hou ◽  
Weican Guo ◽  
Yaoda Zhou ◽  
Xia Chen ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Large Diameter ◽  
Ultrasonic Inspection ◽  
Water System ◽  
Cooling Water ◽  
Operating Pressure ◽  
Traditional Natural

Polyethylene (PE) pipe has many advantages such as good flexibility, corrosion resistance and long service life. It has been introduced into nuclear power plants for transportation of cooling water both in U.S. and Europe. Recently, one Chinese nuclear power plant in Zhejiang Province also introduced four polyethylene pipelines in essential cooling water system with operating pressure of 0.6MPa and operating temperature of no more than 60°C. The PE pipes used in this nuclear power plant are DN762 SDR9 (30in OD, 3.3in wall), which are much larger and thicker than traditional natural gas PE pipe. As the pipe wall is so thick that the ultrasonic phased array instrument used in inspection of PE pipe with diameter less than 400mm has been improved. Results of field inspection in the Sanmen nuclear plant are reported, and the presented ultrasonic inspection technique proves to be effective for high density polyethylene (HDPE) pipe of large size in nuclear power plant.

Calculation of Bounding Pressures Due to Condensation-Induced Water Hammer at the Davis-Besse Nuclear Power Plant in Response to Generic Letter 96-06

2003 ◽  
Author(s):  
G. Thomas Elicson ◽  
James P. Burelbach ◽  
Theodore A. Lang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Water Flow ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Cooling Water ◽  
Water Hammer ◽  
Service Water ◽  
Water Columns

The U.S. NRC is currently evaluating nuclear plant responses to Generic Letter (GL) 96-06, “Assurance of Equipment Operability and Containment Integrity During Design-Basis Accident Conditions” [1]. GL 96-06 is concerned with potential two-phase flow and water hammer conditions that could be present in the cooling water systems of nuclear power plants during design-basis accidents. Nuclear power plants rely on large capacity service water pumps to supply cooling water flow, via an extensive pipe network, to heat exchangers such as room coolers, pump lube oil coolers, and containment air coolers (CACs), for normal and abnormal plant operation. Following a postulated a loss of offsite power (LOOP) event, the normal electrical power supply to the service water pump would be lost resulting in a 20 to 30 second cooling water flow interruption while a diesel generator is started and the service water pump load is sequenced onto the diesel generator. In power plants, such as the Davis-Besse Nuclear Power Plant with open service water systems that draw from a lake or a river and supply safety-related CAC heat exchangers located 30 to 40 feet above the pump outlet, this could lead to cold water column separation in the heat exchanger supply and return piping. If a loss of coolant accident (LOCA) occurs coincident with the LOOP, then boiling in the CAC heat exchanger tubes could occur, as well. Upon restoration of the cooling water flow, dynamic loading could be expected as steam condenses and water columns rejoin. The TREMOLO computer program [2,3] has been used to calculate dynamic thermal hydraulic response and reaction forces in service water piping systems for several nuclear power plants in response to GL 96-06. A consistent result obtained in each of these GL 96-06 analyses is that the LOOP + LOCA scenario produces the bounding loads rather than the LOOP-only scenario. This result seemingly contradicts current industry thinking which suggests that because the water columns are colder and the void fraction lower during LOOP-only scenarios, the LOOP-only loads should be bounding [4,5,6]. While the physics supports the conclusion that the rejoining of colder water columns will generally yield the largest water hammer pressure rise, when actual plant geometry and credible accident scenarios are analyzed, a different picture emerges. This paper couples insights obtained from the GL 96-06 TREMOLO analysis of the Davis-Besse Nuclear Power Plant with independent hand calculations and experimental evidence to support the conclusion that the LOCA+LOOP scenario will produce the bounding loads in service water piping systems.

Research on Earthquake Acceleration Alarm of Nuclear Power Plant

2021 ◽  
Author(s):  
Li Liang ◽  
Pan Rong ◽  
Ren Guopeng ◽  
Zhu Xiuyun
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
False Alarm ◽  
Ground Motion ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Time History ◽  
Seismic Acceleration ◽  
Trigger Signal

Abstract Almost all nuclear power plants in the world are equipped with seismic instrument system, especially the third generation nuclear power plants in China. When the ground motion measured by four time history accelerometers of containment foundation exceeds the preset threshold, the automatic shutdown trigger signal will be generated. However, from the seismic acceleration characteristics, isolated and prominent single high frequency will be generated the acceleration peak, which has no decisive effect on the seismic response, may cause false alarm, which has a certain impact on the smooth operation of nuclear power plant. According to the principle of three elements of ground motion, this paper puts forward a method that first selects the filtering frequency band which accords with the structural characteristics of nuclear power plants, then synthesizes the three axial acceleration time history, and finally selects the appropriate acceleration peak value for threshold alarm. The results show that the seismic acceleration results obtained by this method can well represent the actual magnitude of acceleration, and can solve the problem of false alarm due to the randomness of single seismic wave, and can be used for automatic reactor shutdown trigger signal of seismic acceleration.

scholarly journals Comparison and Evaluation of Domestic and Foreign Radiation Environmental Standards for Nuclear Power Plants

2021 ◽  
Vol 2083 (2) ◽  
pp. 022020
Author(s):  
Jiahuan Yu ◽  
Xiaofeng Zhang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
The United States ◽  
Discharge System ◽  
Radioactive Effluent ◽  
Effluent Discharge ◽  
The Impact

Abstract With the development of the nuclear energy industry and the increasing demand for environmental protection, the impact of nuclear power plant radiation on the environment has gradually entered the public view. This article combs the nuclear power plant radiation environmental management systems of several countries, takes the domestic and foreign management of radioactive effluent discharge from nuclear power plants as a starting point, analyses and compares the laws and standards related to radioactive effluents from nuclear power plants in France, the United States, China, and South Korea. In this paper, the management improvement of radioactive effluent discharge system of Chinese nuclear power plants has been discussed.

scholarly journals Seismic safety evaluation during site selection for the nuclear power plants in Bangladesh

2018 ◽  
Vol 4 (4) ◽  
pp. 251-256 ◽  
Author(s):  
Sergey Shcheklein ◽  
Ismail Hossain ◽  
Mohammad Akbar ◽  
Vladimir Velkin
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Nuclear Fuel ◽  
Heat Removal ◽  
Good Time ◽  
Diagnostics System ◽  
Seismic Impacts

Bangladesh lies in a tectonically active zone. Earlier geological studies show that Bangladesh and its adjoining areas are exposed to a threat of severe earthquakes. Earthquakes may have disastrous consequences for a densely populated country. This dictates the need for a detailed analysis of the situation prior to the construction of nuclear power plant as required by the IAEA standards. This study reveals the correlation between seismic acceleration and potential damage. Procedures are presented for investigating the seismic hazard within the future NPP construction area. It has been shown that the obtained values of the earthquake’s peak ground acceleration are at the level below the design basis earthquake (DBE) level and will not lead to nuclear power plant malfunctions. For the most severe among the recorded and closely located earthquake centers (Madhupur) the intensity of seismic impacts on the nuclear power plant site does not exceed eight points on the MSK-64 scale. The existing predictions as to the possibility of a super-earthquake with magnitude in excess of nine points on the Richter scale to take place on the territory of the country indicate the necessity to develop an additional efficient seismic diagnostics system and to switch nuclear power plants in good time to passive heat removal mode as stipulated by the WWER 3+ design. A conclusion is made that accounting for the predicted seismic impacts in excess of the historically recorded levels should be achieved by the establishment of an additional efficient seismic diagnostics system and by timely switching the nuclear power plants to passive heat removal mode with reliable isolation of the reactor core and spent nuclear fuel pools.

Comparison of Plant Response of Forsmark 3 Nuclear Power Plant to Forsmark 1 Type of Transient (25th July 2006), Using the HAMBO BWR Simulator: Thermal-Hydraulic Aspects

2008 ◽  
Author(s):  
Esko Pekkarinen
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Short Circuit ◽  
Complex Interplay ◽  
Operator Interface ◽  
Control Rooms ◽  
Hydraulic Process

Modernisation of control rooms of the nuclear power plants has been a major issue during the last few years. With this as a basis, the BWR plants in Sweden and Finland funded, in co-operation with the Halden Project, an experimental HAMBO BWR simulator project based on the Forsmark 3 plant in Sweden. VTT Energy in Finland developed the simulator models for HAMBO with the aid of their APROS tool, while the operator interface was developed by the Halden Project. The simulator and its performance have been described in other publications [1, 2]. On July 25th 2006 there was a short circuit at Forsmark 1 nuclear power plant when manoeuvring equipment in the 400kV-switch yard. Due to the short circuit, the plant suffered an electrical disturbance that led to scram and failure of two out of four diesel generators. The purpose of the study carried out at VTT in 2007 was to assess the capabilities of the HAMBO BWR simulator to handle Forsmark 1 type of events in different nuclear power plants (Forsmark 3 in this case). The Forsmark 1 incident showed (among other things) that the intention to protect certain components (in this case the UPS-system) can in certain situations affect negatively to the safety functions. It is concluded that most of this type of BWR transients may be simulated to a certain extent using the existing HAMBO- and APROS- models. A detailed modelling of the automation and electric systems is required sometimes if the complex interplay between these systems and the process is to be predicted reliably. The modelling should be plant specific and level of detail should be assessed case-by-case (i.e. what kind of transient is in question, what systems are available, what is the main purpose of the analyses etc.). The thermal-hydraulic models of the APROS-code seem to replicate well the real behaviour of thermal-hydraulic process provided that there is enough information about the transient in consideration.

scholarly journals “True Believers” or Numerical Terrorism at the Nuclear Power Plant

2011 ◽  
Vol 231 (5-6) ◽  
Author(s):  
Walter Krämer ◽  
Gerhard Arminger
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Childhood Cancer ◽  
Political Party ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
The Political ◽  
Heated Debate ◽  
Data Points

SummaryFor decades, there has been a heated debate about whether or not nuclear power plants contribute to childhood cancer in their respective neighbourhoods, with statisticians testifying on both sides. The present paper points to some flaws in the pro-arguments, taking a recent study prepared for the political party “Bündnis 90 /Grüne” as a specimen. Typical mistakes include an understatement of the size of tests of significance, disregard of important covariates and extreme reliance on very few selected data points.

Explore the Self-Governance on Nuclear Safety Emergency - A Case Study of the 3rd Nuclear Power Plant

2012 ◽  
Vol 260-261 ◽  
pp. 103-106
Author(s):  
Yi Chun Lin ◽  
Yung Nane Yang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Alternative Energy ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Nuclear Safety ◽  
Security Issue ◽  
Safety Issues ◽  
Plant Safety

The ripples of the tsunami crisis in Japan triggered introspections of nuclear plant safety issues in the worldwide. Many countries have claimed the suspension of nuclear power plants. However, some countries such as Taiwan, under nearly 99% energy is exported, the disasters force government and citizen to face the importance of nuclear safety, especially the neighborhoods nearby the nuclear power plants. We have to face the nuclear safety since there is no other alternative energy presently. The 3rd nuclear power plant located in the south of Taiwan, which has the same geographic features with Fukushima, Japan. Presently, there is no precedent in Taiwan of precaution and rescue team and civil supervised mechanic on nuclear security issue. This paper will review according to transparent information, public participation and cross-organization cooperation to propose the execution and work division principles, including information monitor, educational propagation, hide and evacuation, emergence aid and care, rear and refuge service. The ultimate target is to establish self-governance inside nearby neighborhood to confront nuclear disaster at the critical moment.

Sign in / Sign up

Export Citation Format

Share Document