Application of Risk-Informed Methods to Improve Plant Operation at Kozloduy Nuclear Power Plant

2009 ◽  
Author(s):  
Emil Kichev ◽  
Ivan Ivanov ◽  
Kaliopa Mancheva ◽  
Yasen Petrov ◽  
Vesselina Vladimirova ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Level ◽  
Full Range ◽  
Economic Benefits ◽  
Pressurized Water ◽  
Safety Systems ◽  
The Impact ◽  
Service Inspection

Refueling outages at the Kozloduy Nuclear Power Plant (KNPP) Units 5 and 6 are used to perform annual repairs and preventive maintenance activities, piping inspections, and test activities. A refueling outage at KNPP typically requires 60 days and occurs on an annual basis. Testing of safety systems at the KNPP Units 5 and 6 is an extensive exercise that results in multiple actuations of all components during each test and a relatively high number of component actuations each year. This results in equipment wear out issues that can lead to considerable component replacement and/or refurbishment. Numerous piping in-service inspections are conducted in locations where there has been no industry or plant-specific indications or failures, leading to unnecessary personnel exposure. KNPP is interested in using risk-informed (RI) approaches to reduce refueling outage length, piping inspections, testing, and exposure. KNPP is a four-loop Voda-Vodyanoi Energetichesky Reaktor (VVER) with a power level of 1000 MWe. Safety systems consist of three trains. The KNPP at-power probabilistic safety assessment (PSA) model includes internal and external events. It addresses the full range of events leading to core damage frequency (CDF) and includes a simplified level 2 model leading to large early release frequency (LERF). The RI approach, as defined in the U.S. Nuclear Regulatory Commission’s (NRC’s) risk-informed (RI) Regulatory Guides (RGs) 1.174, 1.177, and 1.178, was used in this program. The specific approach used for risk-informed in-service inspection (RI-ISI) is based on the Pressurized Water Reactor Owner’s Group methodology. The overall approach for each of the three applications used a multi-step process which included the following: identification of systems to address; identification of alternatives to current maintenance, inspection, and testing practices; a risk assessment of the proposed alternatives; an assessment of the impact of the changes on deterministic considerations; identification of monitoring requirements; and an assessment of the economic benefits. The RI-ISI program also considered the impact of the changes on personnel exposure. The overall approach made extensive use of data assessments, reliability methods, and risk assessments. The results demonstrated that the proposed changes in maintenance, in-service inspection, and testing programs have a small impact on risk, based on CDF and LERF. In addition, the proposed changes provide significant benefits in terms of reduced outage time, in-service inspections, testing requirements, and personnel exposure. The economic analysis demonstrated that changes to the maintenance program provide the largest benefit followed by the changes to the in-service inspection program and then the changes to the testing program.

On the Feasibility of Nuclear Versus Combustion Gas Turbine Propulsion for High-Speed Cargo Ships

2004 ◽  
Author(s):  
H. Boonstra ◽  
A. C. Groot ◽  
C. A. Prins
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Gas Turbine ◽  
High Speed ◽  
Nuclear Power ◽  
Parametric Design ◽  
Pebble Bed ◽  
Pressurized Water ◽  
Combustion Gas ◽  
The Impact

This paper presents the outcome of a study on the feasibility of a nuclear powered High-Speed Pentamaran, initiated by Nigel Gee and Associates and the Delft University of Technology. It explores the competitiveness of a nuclear power plant for the critical characteristics of a marine propulsion plant. Three nuclear reactor types are selected: the Pressurized Water Reactor (PWR), the Pebble-bed and Prismatic-block HTGR. Their characteristics are estimated for a power range from 100 MWth to 1000 MWth in a parametric design, providing a level base for comparison with conventional gas turbine technology. The reactor scaling is based on reference reactors with an emphasis on marine application. This implies that preference is given to passive safety and simplicity, as they are key-factors for a marine power plant. A case study for a 60-knot Pentamaran shows the impact of a nuclear power plant on a ship designed with combustion gas turbine propulsion. The Prismatic-block HTGR is chosen as most suitable because of its low weight compared to the PWR, in spite of the proven technology of a PWR. The Pebble-bed HTGR is considered too voluminous for High-Speed craft. Conservative data and priority to simple systems and high safety leads to an unfavorable high weight of the nuclear plant in competition with the original gas turbine driven Pentamaran. The nuclear powered ship has some clear advantages at high sailing ranges.

Comparison and Reference Between RSE-M and ASME Section XI Regulations on In-Service Inspection for China Nuclear Power Plant

2017 ◽  
Author(s):  
Sun Haitao ◽  
Zhang Qinghua ◽  
Jia Panpan ◽  
Ling Ligong ◽  
Wang Chen ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Reactor Power ◽  
Mechanical Equipment ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Scope Of Application ◽  
Specific Implementation ◽  
Service Inspection

RSE-M and ASME Section XI regulations are currently recognized as NPP ISI regulations which are most extensively used, most detailed in content and most mature in technology in the world. In China, RSE-M or ASME section XI regulations are used to guide the ISI program preparation, ISI activities implementation and management. There are many differences between RSE-M and ASME Section XI regulations, such as application of regulation, scope of application, main frame and content, basic requirements of ISI, acceptance and evaluation of ISI results, repairing and change. At the same time, some technical clauses can be used for reference by each other, such as qualification and inspection items. By comparison of RSE-M and ASME Section XI regulations for in-service inspection rules of China pressurized water reactor power plant, the technical differences between the two rules are analyzed. Combined with application and engineer practices for in-service inspection of China nuclear power plant, some technical terms used for mutual reference are summarized to provide assistance for establishing the in-service inspection program and specific implementation. During ISI activity, applicable regulation should be chosen according to the requirements of design in consideration of inspection items, examination methods, defect acceptance criteria and evaluation. Meanwhile, implementation of RSE-M and ASME Section XI regulations should be combined with the design features, experience feedback and aging management of mechanical equipment, and draw lessons from mature technical clauses of other regulations.

scholarly journals The Impact of Climate Changes on the Thermal Performance of a Proposed Pressurized Water Reactor: Nuclear-Power Plant

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Said M. A. Ibrahim ◽  
Mohamed M. A. Ibrahim ◽  
Sami. I. Attia
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Thermal Performance ◽  
Nuclear Power ◽  
Cooling Water ◽  
Plant Performance ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
The Impact

This paper presents a methodology for studying the impact of the cooling water temperature on the thermal performance of a proposed pressurized water reactor nuclear power plant (PWR NPP) through the thermodynamic analysis based on the thermodynamic laws to gain some new aspects into the plant performance. The main findings of this study are that an increase of one degree Celsius in temperature of the coolant extracted from environment is forecasted to decrease by 0.39293 and 0.16% in the power output and the thermal efficiency of the nuclear-power plant considered, respectively.

scholarly journals Aerosol dynamics and dispersion of radioactive particles

2021 ◽  
Vol 21 (6) ◽  
pp. 5173-5193
Author(s):  
Pontus von Schoenberg ◽  
Peter Tunved ◽  
Håkan Grahn ◽  
Alfred Wiedensohler ◽  
Radovan Krejci ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Wet Deposition ◽  
Nuclear Power ◽  
Full Range ◽  
Radioactive Material ◽  
Dynamic Processes ◽  
Ambient Aerosol ◽  
Aerosol Dynamics ◽  
The Impact

Abstract. In the event of a failure of a nuclear power plant with release of radioactive material into the atmosphere, dispersion modelling is used to understand how the released radioactivity is spread. For the dispersion of particles, Lagrangian particle dispersion models (LPDMs) are commonly used, in which model particles, representing the released material, are transported through the atmosphere. These model particles are usually inert and undergo only first-order processes such as dry deposition and simplified wet deposition along the path through the atmosphere. Aerosol dynamic processes including coagulation, condensational growth, chemical interactions, formation of new particles and interaction with new aerosol sources are usually neglected in such models. The objective of this study is to analyse the impact of these advanced aerosol dynamic processes if they were to be included in LPDM simulations for use in radioactive preparedness. In this investigation, a fictitious failure of a nuclear power plant is studied for three geographically and atmospherically different sites. The incident was simulated with a Lagrangian single-trajectory box model with a new simulation for each hour throughout a year to capture seasonal variability of meteorology and variation in the ambient aerosol. (a) We conclude that modelling of wet deposition by incorporating an advanced cloud parameterization is advisable, since it significantly influence simulated levels of airborne and deposited activity including radioactive hotspots, and (b) we show that inclusion of detailed ambient-aerosol dynamics can play a large role in the model result in simulations that adopt a more detailed representation of aerosol–cloud interactions. The results highlight a potential necessity for implementation of more detailed representation of general aerosol dynamic processes into LPDMs in order to cover the full range of possible environmental characteristics that can apply during a release of radionuclides into the atmosphere.

14C Distribution in Atmospheric and Aquatic Environments Around Qinshan Nuclear Power Plant, China

Radiocarbon ◽  
2014 ◽  
Vol 56 (3) ◽  
pp. 1107-1114 ◽  
Author(s):  
Zhongtang Wang ◽  
Dan Hu ◽  
Hong Xu ◽  
Qiuju Guo
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Water Samples ◽  
Nuclear Power ◽  
Dissolved Inorganic Carbon ◽  
Tap Water ◽  
Surface Seawater ◽  
Pressurized Water ◽  
Specific Activities ◽  
Water Reactors

Atmospheric CO2 and aquatic water samples were analyzed to evaluate the environmental 14C enrichment due to operation of the Qinshan nuclear power plant (NPP), where two heavy-water reactors and five pressurized-water reactors are employed. Elevated 14C-specific activities (2–26.7 Bq/kg C) were observed in the short-term air samples collected within a 5-km radius, while samples over 5 km were close to background levels. The 14C-specific activities of dissolved inorganic carbon (DIC) in the surface seawater samples ranged from 196.8 to 206.5 Bq/kg C (average 203.4 Bq/kg C), which are close to the background value. No elevated 14C level in surface seawater was found after 20 years of operation of Qinshan NPP, indicating that the 14C discharged was well diffused. The results of the freshwater samples show that excess 14C-specific activity (average 17.1 Bq/kg C) was found in surface water and well water samples, while no obvious 14C increase was found in drinking water (groundwater and tap water) compared to the background level.

scholarly journals 14C Release in Various Chemical Forms With Gaseous Effluents From the Paks Nuclear Power Plant

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 754-761 ◽  
Author(s):  
Ede Hertelendi ◽  
György Uchrin ◽  
Peter Ormai
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Liquid Scintillation ◽  
Mean Value ◽  
Scintillation Counting ◽  
Pressurized Water ◽  
The Mean ◽  
Water Reactors

We present results of airborne 14C emission measurements from the Paks PWR nuclear power plant. Long-term release of 14C in the form of carbon dioxide or carbon monoxide and hydrocarbons were simultaneously measured. The results of internal gas-proportional and liquid scintillation counting agree well with theoretical assessments of 14C releases from pressurized water reactors. The mean value of the 14C concentration in discharged air is 130Bqm-3 and the normalized release is equal to 740GBq/GWe · yr. > 95% of 14C released is in the form of hydrocarbons, ca 4% is apportioned to CO2, and <1% to CO. Tree-ring measurements were also made and indicated a minute increase of 14C content in the vicinity of the nuclear power plant.

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.

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