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.

Incorporation of Risk Insights in the Regulatory Treatment of Nuclear Power Plant Structures, Systems, and Components

2002 ◽  
Author(s):  
Eugene Imbro ◽  
Thomas G. Scarbrough
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Nuclear Regulatory Commission ◽  
The United States ◽  
Special Treatment ◽  
Regulatory Commission ◽  
High Level

The U.S. Nuclear Regulatory Commission (NRC) has established an initiative to risk-inform the requirements in Title 10 of the Code of Federal Regulations (10 CFR) for the regulatory treatment of structures, systems, and components (SSCs) used in commercial nuclear power plants. As discussed in several Commission papers (e.g., SECY-99-256 and SECY-00-0194), Option 2 of this initiative involves categorizing plant SSCs based on their safety significance, and specifying treatment that would provide an appropriate level of confidence in the capability of those SSCs to perform their design functions in accordance with their risk categorization. The NRC has initiated a rulemaking effort to allow licensees of nuclear power plants in the United States to implement the Option 2 approach in lieu of the “special treatment requirements” of the NRC regulations. In a proof-of-concept effort, the NRC recently granted exemptions from the special treatment requirements for safety-related SSCs categorized as having low risk significance by the licensee of the South Texas Project (STP) Units 1 and 2 nuclear power plant, based on a review of the licensee’s high-level objectives of the planned treatment for safety-related and high-risk nonsafety-related SSCs. This paper discusses the NRC staff’s views regarding the treatment of SSCs at STP described by the licensee in its updated Final Safety Analysis Report (FSAR) in support of the exemption request, and provides the status of rulemaking that would incorporate risk insights into the treatment of SSCs at nuclear power plants.

scholarly journals Analysis and Performance Evaluation of Casting Inclusions in the Reactor Coolant Pump Casing of Nuclear Power Plant

2021 ◽  
Vol 257 ◽  
pp. 01076
Author(s):  
Xiaohui Luo ◽  
Jie Yang ◽  
Li Song ◽  
Dezhong Xu
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Material Selection ◽  
Design And Technology ◽  
Coolant Pump ◽  
Impact Performance ◽  
The Impact

The casting quality of the coolant pump casing of the nuclear power plant reactor is directly related to the operational reliability and safety of the nuclear main pump, and plays a key role in the integrity of the pressure-bearing boundary of the reactor primary loop. In this paper, aiming at the low impact performance of the sample during the casting process of the main pump casing of a nuclear power plant, through using failure analysis tools like fishbone diagram from multiple dimensions such as material selection, design and technology, melting analysis, pouring process, riser design, and heat treatment process, and combining with metal macro-fracture analysis and micro-electron microscopy scanning methods for cause analysis, finally, it was found that the basic reason for the low impact performance of the pump shell is that the secondary inclusions appear on the fracture of the sample during the solidification of the molten steel. Using test-retest inspection and finite element mechanics simulation analysis, the comprehensive evaluation of the impact performance of the sample was obtain, which provides an effective solution for the analysis and evaluation of casting inclusions in water pumps of nuclear power plants, and also provides an important reference for the structural optimization and equipment research and development of water pump equipment of nuclear power plants.

Assessment of the content of tritium and its compounds in soil and vegetation in the region of nuclear power plants with VVER type reactors

2021 ◽  
Vol 61 (9) ◽  
pp. 605-610
Author(s):  
Valery G. Barchukov ◽  
Oleg A. Kochetkov ◽  
Dmitry I. Kabanov ◽  
Aleksei A. Maksimov ◽  
Larisa I. Kuznetsova ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Liquid Scintillation ◽  
Laboratory Studies ◽  
Tritium Content ◽  
Environmental Objects ◽  
The Impact

Currently, scientists pay great attention to the intake of tritium and its compounds when assessing the impact of radiation-hazardous objects on the environment and humans. Now, there are no acceptable industrial technologies for the effective capture of this radionuclide; therefore, all tritium generated during the operation of nuclear power plants enters the environment with emissions and discharges. Consequently, it leads to an increase in its concentration in environmental objects, including soil and vegetation. This fact determines the need to assess its content in the ground and vegetation. The study aims to develop a method for determining the content of tritium in soil and vegetation. To develop a methodology for assessing the content of tritium in soil and vegetation, we used the technique of preparing counting samples based on burning the selected examples in a specialized Pyrolyser 6-Trio furnace. Previously, scientists conducted some laboratory studies to assess the acceptability of this method of sample preparation. We measured the counting samples on a Tri-CARB 3180 TR/SL liquid scintillation meter. Scientists have developed and certified a method for determining tritium in soil and vegetation. Furthermore, we investigated the content of tritium and its compounds in the environment in the area of the Nuclear Power Plant based on a comprehensive assessment. Researchers found tritium content in soil and vegetation in settlements near nuclear power plants with VVER type reactors. The main routes of entry of tritium and its compounds into vegetation are the air path and the access of tritium from the ground. The presented data determine the need for systematic studies on the accumulation of tritium in environmental objects.

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 Anti-Earthquake Design of Industrial Facilities

2006 ◽  
Vol 1 (2) ◽  
pp. 190-200
Author(s):  
Heki Shibata ◽  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
The United States ◽  
Potential Hazard ◽  
Oil Refineries ◽  
Probability Of Occurrence ◽  
Aseismic Design ◽  
Low Probability

In Japan two sets of guidelines pertaining to modern aseismic design are being prepared. One is the guideline for the aseismic design of petrochemical plants and oil refineries, and the other is the code of aseismic design of nuclear power plants. The International Atomic Energy Agency also established its own guideline very recently. Several other countries also provide their own codes or guidelines. Among these, the regulatory guides of the United States are well known and quoted often; however some of them seem to be too sophisticated, for example, the three dimensional input problem. The reason for this is that the requirement of safety for a nuclear power plant is so severe that all events which have even a very low probability of occurrence should be considered. Therefore, if the results of theoretical study indicate an event which may occur even in very low probability, then from the viewpoint of conservatism, the designer must consider that event in this design. Although for the design of a nuclear power plant this might be partly true, the author feels that the probability of occurrence of the event should be evaluated in relation to the potential hazard of the design object. As well as this, he believes that proper understanding of the event in relation to the actual record of failures during past destructive earthquakes should be taken into consideration.

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.

Root Cause of Thermal Sleeve Loosening in a Korean Standard Nuclear Power Plant

2006 ◽  
Author(s):  
Sang-Nyung Kim ◽  
Sang-Gyu Lim
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Measurement Data ◽  
Significant Loss ◽  
Design Modification ◽  
Root Cause ◽  
Explosive Expansion ◽  
The Impact

The safety injection (SI) nozzle of a 1000MWe-class Korean standard nuclear power plant (KSNP) is fitted with thermal sleeves (T/S) to alleviate thermal fatigue. Thermal sleeves in KSNP #3 & #4 in Yeonggwang (YG) & Ulchin (UC) are manufactured out of In-600 and fitted solidly without any problem, whereas KSNP #5 & #6 in the same nuclear power plants, also fitted with thermal sleeves made of In-690 for increased corrosion resistance, experienced a loosening of thermal sleeves in all reactors except KSNP YG #5-1A, resulting in significant loss of generation availability. An investigation into the cause of the loosening of the thermal sleeves only found out that the thermal sleeves were subject to severe vibration and rotation, failing to uncover the root cause and mechanism of the loosening. In an effort to identify the root cause of T/S loosening, three suspected causes were analyzed: (1) the impact force of flow on the T/S when the safety SI nozzle was in operation, (2) the differences between In-600 and In-690 in terms of physical and chemical properties (notably the thermal expansion coefficient), and (3) the positioning error after explosive expansion of the T/S as well as the asymmetric expansion of T/S. It was confirmed that none of the three suspected causes could be considered as the root cause. However, after reviewing design changes applied to the Palo Verde nuclear plant predating KSNP YG #3 & #4 to KSNP #5 & #6, it was realized that the second design modification (in terms of groove depth & material) had required an additional explosive energy by 150% in aggregate, but the amount of gunpowder and the explosive expansion method were the same as before, resulting in insufficient explosive force that led to poor thermal sleeve expansion. T/S measurement data and rubbing copies also support this conclusion. In addition, it is our judgment that the acceptance criteria applicable to T/S fitting was not strict enough, failing to single out thermal sleeves that were not expanded sufficiently. Furthermore, the T/S loosening was also attributable to lenient quality control before and after fitting the T/S that resulted in significant uncertainty. Lastly, in a flow-induced vibration test planned to account for the flow mechanism that had a direct impact upon the loosening of the thermal sleeves that were not fitted completely, it was discovered that the T/S loosening was attributable to RCS main flow. In addition, it was proven theoretically that the rotation of the T/S was induced by vibration.

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 Blowout Accident Impact Analysis Method for the Siting of Offshore Floating Nuclear Power Plant in Offshore Oil Fields

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Zhigang Lan
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Impact Analysis ◽  
Oil Spills ◽  
Oil Field ◽  
Oil Fields ◽  
Offshore Oil ◽  
The Impact

Focused on the utilization of nuclear energy in offshore oil fields, the correspondence between various hazards caused by blowout accidents (including associated, secondary, and derivative hazards) and the initiating events that may lead to accidents of offshore floating nuclear power plant (OFNPP) is established. The risk source, risk characteristics, risk evolution, and risk action mode of blowout accidents in offshore oil fields are summarized and analyzed. The impacts of blowout accident in offshore oil field on OFNPP are comprehensively analyzed, including injection combustion and spilled oil combustion induced by well blowout, drifting and explosion of deflagration vapor clouds formed by well blowouts, seawater pollution caused by blowout oil spills, the toxic gas cloud caused by well blowout, and the impact of mobile fire source formed by a burning oil spill on OFNPP at sea. The preliminary analysis methods and corresponding procedures are established for the impact of blowout accidents on offshore floating nuclear power plants in offshore oil fields, and a calculation example is given in order to further illustrate the methods.

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