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Sample records for cernavoda npp unit

  1. NPP Cernavoda Unit 2 Financing Completion Works

    International Nuclear Information System (INIS)

    NPP Cernavoda Unit 2 completion is the highest priority of the Romanian power sector strategy. The nuclear energy represents, through its technological features of adopted solution (a CANDU nuclear power plant) and also through technological and economical performance indicators, the best solution to fulfill the demands concerning the sustainable development and the electricity request. The guidelines of energy strategy regarding the nuclear sector development in Romania are framing in the general policy for energy system development at least costs and they are responding to requests concerning the environment and people protection. The paper presents the financing alternatives for Unit 2 completion works taking into consideration the financing market conditions. The paper presents the impact of the financing conditions on the project efficiency, as well as the facilities offered by the Romanian Government in order to support this project. (author)

  2. Performances of NPP Cernavoda Unit 1 in 1998

    International Nuclear Information System (INIS)

    The paper discusses the performances of NPP Cernavoda Unit 1 in 1998, the second year of commercial operation with reference to the electric power production and to other indicators related to nuclear safety, radioprotection, radioactive wastes and nuclear fuel. A comparison with similar indicators reported by other NPP worldwide is presented. The main stages of the operation history as well as some comments on the unplanned events occurred at NPP Cernavoda during 1998 are presented. The NPP operation costs, in-reactor behavior of the nuclear fuel manufactured at 'Nuclearelectrica', Pitesti and the results of the tests for the determination of the specific nuclear fuel consumption are mentioned. (authors)

  3. Balancing preventive and corrective maintenance in Cernavoda Unit 1 NPP

    International Nuclear Information System (INIS)

    The paper presents a short reminder of Romania's Cernavoda NPP entering commercial operation and a brief description of the CANDU-6 project on which Unit 1 is based. The short term objectives of the maintenance management, the status of the existing maintenance programmes as well as future predictable maintenance programmes are outlined together with the Government plan to complete the balance of NPP. (author)

  4. Cernavoda NPP Units 3 and 4 Equity Approach: Romania

    International Nuclear Information System (INIS)

    The Cernavoda NPP site is located in the Dobrogea, a region in the southeast of Romania as shown in Figure 1. Construction on the Cernavoda NPP site started in 1982, with the intention of building five CANDU 6 units in parallel. Work on Units 2 to 5 stopped in 1990, as the government of Romania focussed its attention on the completion of Unit 1. The core structures of Units 2-4 were left at different stages of completion. Preservation activities were performed on these structures, but were dependent on the available budget

  5. Second loop performance analysis of Cernavoda NPP Unit 1

    International Nuclear Information System (INIS)

    This study aims at simulating the thermal process in the second loop of Cernavoda NPP Unit 1 and analyzing the improvement possibilities of the second loop and NPP's performances by using the CYCLE TEMPO software. At the same time, the software product for the simulation of the second loop of Cernavoda NPP can be a useful tool for operation personnel training. In this respect, this paper can be considered as a doorway into a study on creating a software able to simulate the specific steady state regimes of NPP and specific emerging thermodynamic mis-function of certain components in the secondary loop. A conclusion of this paper is that in the frame of the original design, by keeping the same equipment, there are only minor possibilities for efficiency improvement. (authors)

  6. Cernavoda NPP Unit 1 - a plant of several generations

    International Nuclear Information System (INIS)

    The paper reflects some key aspects related to the shift of generations during the project's development, including the present stage. Further, the place of Cernavoda NPP Unit 1 in the Romanian power sector and among other nuclear stations in the world is presented. The operational performances achieved 'in service' up to the end of 1999, with reference to the performance indicators for electrical energy production, nuclear safety, radiation protection, radioactive wastes and nuclear fuel are illustrated. For all of these items, comparisons are performed with similar indicators reported by other worldwide nuclear power plants, in order to assess our results. Finally, some comments about Cernavoda NPP Unit 2 project status and need to completion and commissioning it are included. (authors)

  7. Integrated maintenance program at Cernavoda NPP - Unit 1

    International Nuclear Information System (INIS)

    The purpose of this paper is to provide the information related to the integrated maintenance program in the Cernavoda Candu plant. The integrated maintenance strategy is the one to provide guidance that can be used to enhance an existing maintenance program by improving the responsibility for plant components and systems maintenance while optimizing resources. The implementation of this guidance will help ensure that tasks for important components are applicable for the types of expected failures and are effective in controlling the failures. This document is showing how the maintenance program is controlled, integrated, enhanced and optimized in Cernavoda NPP. The content of the paper includes: A. The general description of the maintenance program including the main phases as follows: I. MAINTENANCE STRATEGY; II. MAINTENANCE PROGRAMS; Ill. MAINTENANCE PLANS; IV. INTEGRATED MAINTENANCE; V. MAINTENANCE EXECUTION; VI. MAINTENANCE OPTIMIZATION. B. Maintenance Program Objectives. C. Maintenance Performance Indicators. The paper also presents how technical assessment programs can be optimized and interfaced with the executions programs. It also includes a detailed one page description of the strategy plan (appendix one). The final conclusion of this paper is that only a complex comprehensive and integrated maintenance program as it was started and will be applied in NPP Cernavoda is assuring a safe and reliable production for the unit. (author)

  8. Implementing the Environmental Management System ISO 14001 at the Cernavoda NPP Unit 1

    International Nuclear Information System (INIS)

    An environmental management plan (EMP) has been developed for the Cernavoda NPP Unit 1. It contains the necessary components for identification and management of the environmental aspects of NPP. The environmental policy of the 'Nuclearelectrica' National Society and the associated EMP are the basis for the Environment Management System that will be implemented at Cernavoda NPP. The final step of this process will be the ISO 14001 certification. This paper points out to the main aspects concerning the implementation of the ISO 14001 system at Cernavoda NPP Unit 1. (author)

  9. Risk management solutions for Cernavoda Unit #2 NPP completion

    International Nuclear Information System (INIS)

    The greatest risk facing today's electric utilities is change. Utility risk managers are being challenged to address the changes of deregulation, new technologies and changing work force. The utilities must be more aware of where all its costs are located to face with the challenge of competition, forcing them to respond with lower prices and innovative services. For completion of large projects, like Cernavoda NPP, Unit 2, the utilities are facing also with certain specific risks: politic, economic, social. The natural perils or machinery breakdown are common risks for operation as well as for construction-commissioning projects. Beyond the explicit challenges associated with the completion of a nuclear power plant in a transition economy environment, the utilities are facing with new risk factors such as professional liability, political risk, product warranty and liability, international exposure, etc. Changes in other governmental policies are also affecting large projects, mentioning healthcare, workplace safety, workers' compensation, environmental clean up, etc.(author)

  10. Financing nuclear projects. Case study: Unit 2 Cernavoda NPP

    International Nuclear Information System (INIS)

    The implementation of a Nuclear Power Plant (NPP) in a country is a major undertaking for all entities involved, due to the necessity of planning work and co-ordination of the implementation process of the different fields of interest, starting with the governmental authorities and ending with the people. Having in view the specific investment cost (relatively high) for a NPP, to find an adequate financing structure is possible through an iterative process that involves first an assessment of the technical performances of the project and second, the mathematical modelling of the financing structure effects on the project. In this respect, the paper proposed will be focused on the main steps needed in order to promote an investment project in nuclear field, starting with the decision phase, providing the documentations requested by the local and international authorities to promote the project and ending with the negotiation of the contracts (commercial contract, financing contract, power purchase contract, etc.) The case study will be focused on the phases achieved in order to promote the Unit 2 Cernavoda NPP completion works project. (author)

  11. Specific aspects for Cernavoda - Unit 1 NPP life assurance

    International Nuclear Information System (INIS)

    Full text: The main scope of a Plant Life Management Program is to operate the NPP in a safe manner and at a competitive cost during the reactor life. To achieve this goal, it is important to continuously evaluate the degradation of the main structures and components of the NPP. Background -Cernavoda NPP design life is 30 years. Compared with this target, the operation history is not long (Unit 1 is in commercial operation since 1997). It is still important to begin a plant life management program early to identify the critical components and structures, to establish the data needed for their monitoring and to find methods to mitigate their degradation. A specific aspect for Cernavoda NPP - Unit 1 is the long delay between the fabrication of the main components and the start-up. Most components were procured 10-15 years before start-up. First criticality was achieved in 1996, but the containment perimeter wall sliding was complete in 1983, the Calandria vessel was installed in 1985, the Steam Generators were in position in 1987, the fuel channels were installed in 1989. In evaluating the history of these components, the preservation period must be observed. For Unit 2, which will be in service around 2005, the delay will be longer. For this reason, CNCAN (the Romanian Regulatory Authority) imposed, as a condition to resume the work, to evaluate the ageing of the existing components and structures in order to establish their acceptability for use in the plant. The results of this evaluation can be used as references for subsequent evaluations. Plant Life Assurance Programme - The first step of a PLIM programme is to identify the components and structures that are important for the plant life management. Critical components and structures selection is done using the following criteria: safety criteria - components and structures whose failure can cause a release of radioactivity or which have to mitigate the release of radioactivity in case of a failure of other

  12. Cernavoda NPP Unit 2 and Romanian nuclear industry

    International Nuclear Information System (INIS)

    On 18 May 2001, in the presence of Mr. Adrian Nastase, the Prime-Minister of Romania, the presidents of AECL, ANSALDO and Director General of SN Nuclearelectrica, the commercial and management contract for completing the Cernavoda NPP Unit 2 was signed. This document stipulates the goal and the partners' commitments, leadership organization, the SN Nuclearelectrica's control of the Budget, costs for the technical assistance (around 180 specialists from abroad), as well as the costs of equipment supplied from Canada and Italy. Services and equipment supplied by Canada and Italy amounts up to around USD 300 millions. Efforts are currently undertaken to obtain a loan of USD 300 millions from EURATOM, beginning from 2003. An auction process, implying around 10 companies, is underway and by the completion of the process, in February 2002, the practical delivery of equipment will start. The so-far invested capital amounts around USD 650 millions while the capital funds remaining to be invested amounts up to about USD 689 millions. From the latter figure, around USD 100 millions represent the costs for heavy water and the initial nuclear fuel charging. The personnel dynamics is presented as well as problems relating with recruitment and salary policy. Romanian nuclear industry is engaged for supply of a series of important components. General Turbo SA, supplied already components of some tens USD millions for the turbogenerator complex. PETROTUB company from Roman, Romania supplied already one thousand tones of non-nuclear carbon steel tubing valued at about USD 300 millions. ARIO, Bistrita, Romania, has signed contracts valued at about USD 400,000 for non-nuclear reinforcing materials. Other companies like AVERSA SA and Ventilatorul SA supplied reliable equipment for Unit 1 and will continue to do the same for Unit 2. Contracts of over one million USD are carried on with VULCAN for carbon steel fittings and with TITAN Nuclear Equipment for components of the fueling

  13. Reviewing NPP Cernavoda site evaluation

    International Nuclear Information System (INIS)

    The Nuclear Power Plant Cernavoda site was selected before the IAEA Safety Guide issue, during NUSS program development. The Romanian codes issued in 1976, as a regulatory body requirements, establish general criteria regarding safety concept and concentration limits of different radionuclides in air and water body and limits of individual or collective dose. In 1979 the Romanian Authority signed the contract with AECL to improve the CANDU-600 concept in the nuclear development programme and erection of 4 units on the Cernavoda site. The construction work started in 1980. In 1983 the former Romanian Government decided to build up another unit (finally it will be 5 units) on Cernavoda site, so the total gross electrical power we have 3,500 MW. The Canadian safety and quality standards or requirements was harmonized with the Romanian rules and regulations. Many studies, investigations and research were done to qualify the site and have a good knowledge about its characteristics coupled with CANDU-600 performance. The new evolution of the site was performed by Romanian technical staff in CITON and the final conclusions were favourable for erection and operation of NPP. The first unit of Cernavoda NPP is on operation and now the efforts are concentrated to continue the works for the unit 2. The paper underlines how the Cernavoda site characteristics meet IAEA Code of Practice and Safety Guides issued until now. (author)

  14. Cernavoda NPP Unit 2: 'A year of progress'

    International Nuclear Information System (INIS)

    available for installation. An unfortunate incident in shipping of the generator stator from the USA at the end of 2003 meant a delay in the delivery by 10 months. Through a major team effort by all concerned the unit was rebuilt and delivery successfully effected in November. All of the major obstacles have been overcome and the project is currently on schedule. The project has now completed 482 days of work without a lost time accident which is notable considering that over 4 million man-hours were worked during this period. AECL Canada and ANSALDO Energia have worked hard to support the project. The foreign engineering scope of work is nearing completion and all contract scope purchase orders have been placed with most deliveries now completed. Work still continues on procurement to support the commissioning of the plant systems. The success to date is attributed partly to providing a strong Management Team consisting of personnel who bring experience from similar projects in China, Italy and of course Cernavoda Unit 1. The client and Romanian ministry of trade and industry are fully supportive of the project and working as a team with the MT is a key element to meeting the challenges that exist on a large project such as the Cernavoda 2 Plant and has been a key factor in the success to date. The coming year will be no less demanding, by the end of 2005 virtually all systems will be transferred from the construction to the commissioning group. The key issue that will have to be addressed by the project will be acquiring sufficient site construction contractor's manpower to meet the demands imposed by the aggressive systems turn over schedule and delivery of large amounts of materials. Commissioning will also have a major challenge to keep up with some 25 systems being turned over on a monthly basis. Staffing levels for Construction Division will be reduced while a similar increase will occur in Commissioning. With the support of the client SNN the Management Team at

  15. Appendix II: Training of personnel for the commissioning of Cernavoda NPP Unit 2 (Romania)

    International Nuclear Information System (INIS)

    Nuclear power generation is a reliable source of energy for Romania and an important contributor to the national electricity supply. Romania has one nuclear power plant, Cernavoda, which operates one CANDU 6 reactor, 707 MWe, designed by Atomic Energy of Canada Ltd (AECL). It provides about 10% of the total country electricity generation. The state-owned company responsible for the production and supply of energy from Cernavoda NPP, as well as for its development, is Societatea Nationala 'Nuclearelectrica'. The plant was designed to have five similar units. The studies performed for the plant, prior to the construction's start, established feasible technical solutions for all problems related to a 5- units plant, including the environmental impact, which was determined to be entirely acceptable. Construction of the first unit started in 1980, and units 2-5 in 1982. The pressing problems encountered during construction of Unit 1 (import restrictions, delays etc.) restrained the progress at Unit 2. Starting in 1990, the work on Cernavoda site was focused on Unit 1. Construction at the other units was suspended; during many years; only preservation works were carried-out. The re-start of work at Unit 2 began in 1995, under the management of the AECLANSALDO Consortium. Some work to further construction progress was carried-out (e.g. installation of the fuel channels) and a thorough assessment was performed of the condition of the equipment procured for Unit 2 and stored on site, or already installed. The absence of a clear contractual framework and the lack of resources hindered significant advances in the construction of Unit 2. Recently, estimates in Romania are that annual electricity production will become insufficient unless Unit 2 of Cernavoda NPP is commissioned. In this environment and considering the relatively low cost of the electricity produced at Unit 1 of Cernavoda NPP versus the energy cost in the conventional thermal stations, the Romanian Government

  16. Cernavoda NPP simulator - next generation

    International Nuclear Information System (INIS)

    Demand for extending the amount of training and scope for Cernavoda Unit 1 as well as the new trend in the simulator owners world, led to a change in the Romanian philosophy of simulator specification. Up to now the training was conducted on a Full Scope simulator, a 1:1 replica of Cernavoda Unit 1 reference plant. The present task is to define the simulation facilities and structure capable to meet the requirements for training, qualification and licensing of personnel for both Cernavoda Unit 1 and Unit 2. Obviously, the Cernavoda Unit 2 belongs to the same technological family but has rather different control room layout. Since this target requires a new simulator the costs would be rather high in accordance to the degree of automation of Cernavoda NPP. Therefore, depending on training requirements and financing, the Cernavoda Unit 1 simulator modernization, which also provides an alternative to full scope control room simulator, may be a viable option. Therefore the solution that with discuss for Cernavoda training extension is the migration of Cernavoda Unit 1 simulator to state-of-the-art. Consequently, the Cernavoda Unit 1 simulator modernization task will be organized as project including the following major items: 1. Rehost existing U1 simulation software from VAX 4500 to: - Best commercial multi-processor server for simulation server (HP, O/S Linux); - Best commercial single processor PC for I/O communications (HP, O/S Linux); 2. Replace DCC with enhanced emulated version: Best commercial individual PC for DCC emulation (HP, O/S Windows); Support for actual keyboards; Replacement of RAMTEK System and CONRAC Monitors with X terminals or PC's; 3. Conversion of AutoCAD-based panel graphic pages to RAVE-based; 4. Install the required software tools for developing enhanced simulation modules; 5. Replace the simulation modules with advanced modules; 6. Replace the present Windows Instructor Facilities with ISIS; 7. Development of a selection of MCR-U1 virtual

  17. The PHWR CANDU 6 from Cernavoda NPP Unit 2 against the European Utility Requirements (EUR)

    International Nuclear Information System (INIS)

    In the beginning of 2007 Romania became a country member of the European Union. Within this new context it is necessary to asses the technological level of nuclear field from our country comparatively to the actual requirements for the nuclear field from the member countries of EU. These requirements based on the nuclear field current regulations from the member countries of EU and on their operational experience on LWR Nuclear Power Plant type, were gathered and colligated together in the 'European Utility Requirements (EUR)'. The requirements are structured in chapters and sections related to the main design process, construction and operation of LWR NPP fields. The EUR documents are applicable to the whole plant, up to the external electrical grid, at the limit of the switches which connect the electrical stations to the outside high voltage bus bars. Even the Cernavoda NPP Unit 1 and Unit 2 design is a PHWR CANDU 6 design type, after an analysis it is concluded that the majority of the EUR requirements are available too for this design type. Another goal of this analysis was to evaluate the level of the fulfillment of the applicable EUR requirements by the Cernavoda NPP Unit 2 design and to establish a set of measures which are necessary to implement for current PHWR CANDU 6 design for Unit 3 and 4 in order to be in accordance with all applicable EU standards. (authors)

  18. The international cooperation and partnership, keystones for engineering and procurement for Cernavoda NPP Unit 2

    International Nuclear Information System (INIS)

    Romania is experiencing the second year as a member of the European Union, and is crossing a crucial year in implementing the national energy strategy. The last year European Community documents, as an energy policy for Europe or the nuclear illustrative programme, has provided the guidelines for the new Romanian energy strategy, based on the principles of supply security, competitiveness, environment protection and optimization of the use of domestic natural resources. In line with the right of each European state of for choosing the proper energy mix, in order to be able to face the predicted deployment of natural gas and oil resources, Romania has to re-direct its strategy to improve the energy efficiency, to develop renewable energies and to extend nuclear energy use. Romania has developed the national infrastructure for the implementation, management and operation of the nuclear power projects, including the environment protection aspects. The Ministry of Economy and Finance is responsible for the national power strategy, including NPP projects implementation and operation. Other important actors are the Ministry of the Environment, the Nuclear Agency, the Nuclear Regulatory Body - CNCAN and the National Agency for Radioactive Waste - ANDRAD and, acknowledged Societatea Nationala Nuclearelectrica SA, the operator of Cernavoda NPP. For Romania, the nuclear energy represents an obvious reality, strongly proved by the following major achievements: - The high performance recorded by Cernavoda NPP Unit 1 along 12 years of commercial operation; The commissioning of the Cernavoda NPP's Unit 2, on October 5 2007 - the most recent success of the Romanian nuclear industry; Completion of the Cernavoda NPP Units 3 and 4, as a new challenge optimistically facing by the Romanian society. Nuclear power is part of the energy policy promoted by the Romanian Government to develop the nuclear energy as part of the European policy, considering (1) sustainable development, (2

  19. The International Cooperation and Partnership, Keystones for Engineering and Procurement for Cernavoda NPP Unit 2

    International Nuclear Information System (INIS)

    Romania is starting the second year as a MS of the EU, and is crossing a crucial year in implementing the national energy strategy. The EC documents from last year, as an energy policy for Europe or the nuclear illustrative programme provided the guidelines for the new Romanian energy strategy, based on the principles of security of supply, competitiveness, environment protection and optimization of the use of domestic natural resources. In the line with the right of each European state to choose the proper energy mix, in order to face the predicted deployment of natural gas and oil resources, Romania has to redirect its strategy to improve the energy efficiency, develop the renewable energies and to extend the use of nuclear. Romania has developed the national infrastructure for implementation, management and supervision of the nuclear power projects, including the environment protection aspects. The Ministry of Economy and Finance is responsible for the national strategy in the energy field, including NPP projects implementation and operation. Other important actors are the Ministry of the Environment, the Nuclear Agency, the Nuclear Regulatory Body - CNCAN and the National Agency for Radioactive Waste - ANDRAD. For Romania, the nuclear energy represents an obvious reality, strongly proved by good performances registered by Cernavoda NPP Unit 1 during over 12 years of commercial operation: High quality of the nuclear fuel produced by Nuclear Fuel Plant in Pitesti - as demonstrated by the 7 consecutive years of operation of Cernavoda Unit 1 without detecting a single fuel bundle with nuclear defect, the very good quality of heavy water produced in Romania based on Romanian concept and technology and, by the most recently success of the Romanian nuclear industry: commissioning of the second Unit at Cernavoda NPP on October 5. 2007. All those represent achievements of entire Romanian society for which the education, research, design engineering and operation of

  20. The International Cooperation and Partnership, Keystones for Engineering and Procurement for Cernavoda NPP Unit 2

    Energy Technology Data Exchange (ETDEWEB)

    Stiopol, Mihaela; Vatamanu, Mariana; Bucur, Cristina [Nuclearelectrica SA, 65 Polona Street, 010494 Bucharest (Romania)

    2008-07-01

    Romania is starting the second year as a MS of the EU, and is crossing a crucial year in implementing the national energy strategy. The EC documents from last year, as an energy policy for Europe or the nuclear illustrative programme provided the guidelines for the new Romanian energy strategy, based on the principles of security of supply, competitiveness, environment protection and optimization of the use of domestic natural resources. In the line with the right of each European state to choose the proper energy mix, in order to face the predicted deployment of natural gas and oil resources, Romania has to redirect its strategy to improve the energy efficiency, develop the renewable energies and to extend the use of nuclear. Romania has developed the national infrastructure for implementation, management and supervision of the nuclear power projects, including the environment protection aspects. The Ministry of Economy and Finance is responsible for the national strategy in the energy field, including NPP projects implementation and operation. Other important actors are the Ministry of the Environment, the Nuclear Agency, the Nuclear Regulatory Body - CNCAN and the National Agency for Radioactive Waste - ANDRAD. For Romania, the nuclear energy represents an obvious reality, strongly proved by good performances registered by Cernavoda NPP Unit 1 during over 12 years of commercial operation: High quality of the nuclear fuel produced by Nuclear Fuel Plant in Pitesti - as demonstrated by the 7 consecutive years of operation of Cernavoda Unit 1 without detecting a single fuel bundle with nuclear defect, the very good quality of heavy water produced in Romania based on Romanian concept and technology and, by the most recently success of the Romanian nuclear industry: commissioning of the second Unit at Cernavoda NPP on October 5. 2007. All those represent achievements of entire Romanian society for which the education, research, design engineering and operation of

  1. A DCS application on Cernavoda NPP-Unit 2

    International Nuclear Information System (INIS)

    The technology of the formerly used Control Architecture for BOP area and some support systems is substantially based on hardware interconnections 'point to point' between field instruments, transmitters and switches, logic cabinets in Equipment Room (ER), with electronic cards and cabled static elements, and a conventional operator interface in Main Control Room (MCR), local panels with hand-switches, electromechanical indicators, lamps and chart-recorders. Functional group commands, operable by ER cabinets, and single component commands, operable directly from local panels close to the drivers in field, are also available. The digital signals to/from field or MCR are transmitted to/from the logic cabinets passing through a centralized Control Distribution Frame (CDF). It provides also the signals dispatching between the different I-and-C systems used (included the AECL computers, where trending, data logger, supervision activities and some control function are realized), and signal hardware application when it is necessary. The criteria leading to the choice of a product to implement a new control architecture have been: - the capability to fulfill all the current Unit 1 Control System requirements and some additional ones forced by the present up-dating; - the use of a modern technology, with the possibility to easily extend its features, enhancing the process control capability, the global performances, the operating and maintenance activities; - the choice to limit the impacts, mainly in terms of human machine interface variations and, moreover, the replacement cost. In the section of the paper entitled Distributed Control System (DCS) the main features are described and the issues of hardware reduction, software and control system layout optimizations, as well as an advanced operator interface are presented. The section three is dealing with a proposal for Unit 1 Control Architecture while in the section four the DCS v.s. traditional technology is discussed

  2. Public debates - key issue in the environmental licensing process for the completion of the Cernavoda NPP Unit 2

    International Nuclear Information System (INIS)

    SN 'NUCLEARELECTRICA' S.A., the owner of Cernavoda NPP, organized, in 2001, several public consultations related to environmental impact of the completion of the Cernavoda NPP Unit 2, as required by the Romanian environmental law, part of project approval. Public consultations on the environmental assessment for the completion of the Cernavoda NPP - Unit 2 took place in 2001 between August 15 and September 21 in accordance with the provisions of Law No. 137/95 and Order No. 125/96. Romanian environmental legislation, harmonization of national environmental legislation with European Union, Romanian legislative requirements, information distributed to the public, issues raised and follow-up, they all are topics highlighted by this paper and they are addressing the environmental licensing process of the Cernavoda 2 NPP. The public consultation process described fulfils all the Romanian requirements for carrying out meaningful consultation with its relevant shareholders. The process also satisfies EDC (Export Development Corporation - Canada) requirements for public consultation and disclosure with relevant shareholders in the host country. SNN is fully committed to consulting as necessary with relevant shareholders throughout the construction and operation of the Project. Concerns of the public have been taken into account with the operations of Unit 1 and will continue to be addressed during the Unit 2 Project

  3. Review of site data for Cernavoda NPP

    International Nuclear Information System (INIS)

    The review of CANDU-PHWR-700 standard design according to the geological and seismic conditions of Cernavoda NPP site was made during the period 1980-1985 based on the geological, geotechnical, seismological design data as well as based on the design data for ground dynamics assessed in 1980. During the construction period of Unit 1 and partially of Unit 2-5, some observations ad in-situ and lab determinations have been done, resulting in additional information as to the ones determined during the period of site studies. Considering all the geological, geotechnical, seismic and ground dynamics data obtained both during the site investigation period and the construction period of Unit 1 and partially of Unit 2-5, a review of the site data was made in order to determine a representative set of data for Cernavoda NPP site, as well as to reduce the conservatory degree existing in the initial data. (author). 1 fig., 1 tab., 6 refs

  4. Works on ageing management for Cernavoda NPP

    International Nuclear Information System (INIS)

    The document presents a general overview of the activities realized by CITON in the area of ageing management for Cernavoda NPP components. There are considered especially safety related components. The initial activity in this field started with general analyses of ageing phenomena implication on NPP safety and establishment of a general program for ageing management. During 1994-2000 period a series of research and development works included in 'Nuclear Safety Research and Development Program' financed by Ministry of Industry and Resources allowed the completion of important steps in ageing management: condition indicators definition, selection of systems and components necessary of ageing monitoring and evaluation, establishment of initial reference values for selected components monitoring, etc. Starting with 2001 year the ageing program includes evaluation of the service life for main of components (one system after the other approach), evaluation of present surveillance and data collection and proposal for improvement by computerized data acquisition and processing, extension of system, ageing evaluation for the whole plant critical components, both from safety and availability point of view. This program, with proper support and cooperation from the NPP owner, will allow first evaluation of the whole Cernavoda NPP - Unit 1 ageing, safety and availability implications and presentation of recommendations for operating conditions and maintenance optimization. The document emphasizes also the status of Cernavoda units, from ageing management point of view and the necessary actions to be adopted (in CITON opinion). (authors)

  5. Cernavoda NPP Unit 1: Ensuring heat sink at very low Danube river levels

    International Nuclear Information System (INIS)

    Full text: On August 24, 2003 the summer heat wave has caused the Danube River to drop to its lowest level in more than a century, forcing a government commission of experts and a team of technical specialists from Cernavoda NPP to close Romania's unique nuclear reactor in operation at Cernavoda. The paper presents some of the required actions needed for plant shutdown and ensuring adequate fuel cooling at very low suction bay levels, due to the Danube River level drop (Danube waters cools the reactor). The water level in the Danube River at Cernavoda village, where the reactor is located, fell to a depth of less than three meters (10 feet) on Saturday, down from its usual level of almost seven meters (23 feet). Consequently, the Unit 1 nuclear power plant was shut down Sunday due to this record drought, which left insufficient water to cool down the reactor. Operating Instruction procedures were elaborated in order to provide a logical sequence of actions when the bay level decreases under 2.25 m, or the estimated level after 3 days will be lower than 1.8 m. When Raw Service Water (RSW) is lost, Recirculated Cooling Water (RCW) will remain in service only for Moderator, ESC, HT Pumps, HT Purification, D/C Cooler, LAC's, and D2O Feed Pump. Alternate water sources, like potable water and water from the fire protection system were taken in consideration in order to ensure heat sink to the RCW loads. At the same time, in case of total loss of Class III and Class IV Power, and Stand-By Diesel Generators unavailable because of the loss of heat sink provided by the RSW, Emergency Power System (EPS) was configured to supply directly the Class III Power 6 kV bus (BUG bus). Economical Impact According to a report, closing the nuclear plant costs Romania $500,000 a day. The total cost includes also losses due to a 40 percent reduction in hydroelectric power generation due to reduced river flow. The country had to cease power exports until the reactor comes back on line

  6. Nuclear safety and environment protection at Cernavoda NPP

    International Nuclear Information System (INIS)

    The paper reviews the basic features of nuclear safety of CANDU 600 reactor in operation at Cernavoda NPP and the measures aimed at safety improvement of this type of reactor, especially for the Units 1 and 2. The authors also present the method used for ensuring the environment and population protection during normal operation of NPP as well as in case of emergency. The paper contains the following chapters: 1. Fundamental aspects of nuclear safety at Candu 600 reactor based Cernavoda NPP; 2. A comparison between CANDU-600 and PWR reactors from technological and nuclear safety point of view; 3. Severe accidents with CANDU-600 type reactors; 4. The reactor CANDU-600 facing the European Union requirements for LWR; 5. Design improvements of the CANDU-600 reactor operating at Cernavoda NPP; 6. Environmental and population protection with CANDU-600 reactors and particularly Cernavoda NPP; 7. Emergency plans in the frame of population protection measures

  7. NPP Cernavoda unit 2 economic viability: The challenge for an advanced financing scheme

    International Nuclear Information System (INIS)

    The completion of Cernavoda Unit-2 being no doubt, the viability of the project was analyzed and strengthened. Economic justification of the decision to complete Unit-2 is described, including assessment of its safety design guides, design requirements and engineering design solutions in the light of changes in codes, guideline, standards and actual regulatory requirements. Cost-benefit analysis demonstrates the economic viability of the project

  8. Seismic risk at NPP Cernavoda

    International Nuclear Information System (INIS)

    The paper presents a brief description of the probabilistic analysis method employed to analyze a nuclear power plant (NPP) state during seismic events. For evaluating the seismic hazard at NPP Cernavoda, deterministic judgment are employed for determining the focus position, the attenuation of the seismic intensity and the local effects. The authors have designed a support device which can operate in damping regimes or as a snubber having also the function of non-linear elastic support with a progressive characteristic for permanent loads. This support can take over very great static and dynamics loads. The support and damping devices are hydro-pneumatic systems which completely eliminate the gaskets. The non-linear elastic supporting force is provided by compressing a volume of gas and the damping force is provided by a liquid flowing through a system of calibrated nozzles covered on one side or the other by a set of elastic blades of an imposed stiffness. The sizes and weight of the devices are under the ones of the current devices and they provide higher reliability. (Author)

  9. Presentation on management of delayed Cernavoda unit 2 NPP nuclear projects. Regulatory body assessment

    International Nuclear Information System (INIS)

    In 2003 the owner SNN signed the contract with AECL/ANSALDO to finalize together (management team) unit 2. The CNCAN requirements for Cernavoda unit 2 fully construction licence are: preliminary safety analysis report (PSAR); system classification list; item classification list; compliance report on safety Canadian regulation regarding the special safety systems (SDS 1, SDS 2, ECCS, Containment). The well-known CANDU design, easy to compare PSAR from unit 1 with unit 2 FSAR and improvement in accident analysis are the advantages of actual base for construction licence. Missing of design manuals to submit to CNCAN in this phase, special and expensive evaluation of safety implication for the equipment procured in the early time of project that compliance with obsolete codes are the main disadvantages of actual base for construction licence. The following additional document for the licence are required: training program for main control room operators; information about the availability of technical staff for commissioning; list of unit 2 procedures required to be approved by CNCAN; commissioning schedule for main control room ect

  10. Cernavoda NPP training programs The paper presents a general assessment of Cernavoda NPP personnel training programs,

    International Nuclear Information System (INIS)

    The paper presents a general assessment of Cernavoda NPP personnel training programs, highlighting the role of training in human performance improvement. Cernavoda NPP Personnel Training and Authorization Department (PTAD) is responsible for the training of CNE Cernavoda NPP personnel and its contractors. PTAD is structured in a manner ensuring the support and response to all plant training, qualification and authorization requirements. The training of personnel is continuously adapted based on IAEA Guides and INPO/WANO recommendations, to keep with world standards, based on the internal and external reviews. At Cernavoda NPP the Training Concept and the Training Programs are based on SAT - Systematic Approach to Training. The Training Concept is established on a set of training documents (RD's, SI's, IDP's), which address all the SAT phases: Analysis, Design, Development, Implementation and Evaluation. The Training Programs are structured on the initial and continuing personnel training. Their content and goals are responding to the training specific needs for each plant major job family. In order to successfully support NPP training programs, CNPP training center has upgraded classrooms with new presentation facilities and there are plans to expand the space of the building, to develop additional operator and maintenance skills facilities. By responding in a timely and completely manner to all plant training requirements PTAD will help in rising human performance of Cernavoda NPP personnel, supporting the safe, efficient and cost effective production of power. (author)

  11. Romanian contribution to the design of Cernavoda NPP

    International Nuclear Information System (INIS)

    The Cernavoda NPP is the first nuclear power unit built in Romania. It resulted as implementation of the national nuclear program provisions worked out in the period 1960-1978. The Center of Technology and Engineering for Nuclear Projects operated in the Cernavoda NPP construction in its capacity of general and specialty designer. It conducted studies and design works to select optimal nuclear reactor system, nuclear fuel cycle and associated nuclear materials (D2O, Zr), aiming particularly to the introduction of CANDU type power reactors in the Romanian power system. In the period 1977-1990 basic technical and economical documentation were worked out concerning the site of construction, technical annexes to the commercial contracts, procurement order documents, technical assistance on site of construction, design for equipment fabrication, etc. In 1990-2002 significant changes in conducting the project have taken place. In the period August 1991- June 1996 the project management was taken over by the ACC consortium formed of AECL (Canada) and ANSALDO (Italy), while CITON was acting as principal contractor of ACC for design services and technological engineering. The paper presents the following main achievements in the design work: site selection and NPP general layout; nuclear safety and environmental protection; structure and infrastructure works; anti-seismic design; design of process systems; thermomechanical equipment for the NPP nuclear sector; design for electrical systems and automation. In conclusion, the contribution to the design and construction of the Romanian specialists for realization of Cernavoda NPP Unit 1 was decisive, while the cooperation with Canadian and Italian teams was extremely fruitful. These constitute a valuable potential to be used in building the Cernavoda NPP Unit 2 and Units 3-5

  12. Improvement of nuclear safety at Cernavoda unit 1 NPP considering results of periodic safety review and Fukushima stress tests

    International Nuclear Information System (INIS)

    The main responsibility to maintain a high level of nuclear safety and to improve the nuclear safety of Nuclear Power Plants (NPP) lies with their operation who is supervised by the national independent regulators. Throughout the last years, the nuclear safety of the worldwide NPPs suffered a significant improvement due to operational feedback and development of new nuclear plant design. For its part, the nuclear safety of Cernavoda NPP also has suffered a number of significant improvements obtained: - through an Periodic Safety Review (PSR) performed in order to obtain an overall view of actual plant safety, to determine reasonable and practical modifications that should be made in order to maintain a high level of safety and to improve the safety of older nuclear power plants to a level approaching that of advanced plants; - performing the stress tests in order to reassess the safety margins in the light of the events which occurred at Fukushima: extreme natural events challenging the plant safety functions and leading to a severe accident. The main nuclear safety improvements at Cernavoda NPP resulting from the results of the PSR Project and from Stress Tests are shortly presented in this report. (authors)

  13. Development of new process network for gas chromatograph and analyzers connected with SCADA system and Digital Control Computers at Cernavoda NPP Unit 1

    International Nuclear Information System (INIS)

    The continuous monitoring of gas mixture concentrations (deuterium/ hydrogen/oxygen/nitrogen) accumulated in 'Moderator Cover Gas', 'Liquid Control Zone' and 'Heat Transport D2O Storage Tank Cover Gas', as well as the continuous monitoring of Heavy Water into Light Water concentration in 'Boilers Steam', 'Boilers Blown Down', 'Moderator heat exchangers', and 'Recirculated Water System', sensing any leaks of Cernavoda NPP U1 led to requirement of developing a new process network for gas chromatograph and analyzers connected to the SCADA system and Digital Control Computers of Cernavoda NPP Unit 1. In 2005 it was designed and implemented the process network for gas chromatograph which connected the gas chromatograph equipment to the SCADA system and Digital Control Computers of the Cernavoda NPP Unit 1. Later this process network for gas chromatograph has been extended to connect the AE13 and AE14 Fourier Transform Infrared (FTIR) analyzers with either. The Gas Chromatograph equipment measures with best accuracy the mixture gases (deuterium/ hydrogen/oxygen/nitrogen) concentration. The Fourier Transform Infrared (FTIR) AE13 and AE14 Analyzers measure the Heavy Water into Light Water concentration in Boilers Steam, Boilers BlownDown, Moderator heat exchangers, and Recirculated Water System, monitoring and signaling any leaks. The Gas Chromatograph equipment and Fourier Transform Infrared (FTIR) AE13 and AE14 Analyzers use the new OPC (Object Link Embedded for Process Control) technologies available in ABB's VistaNet network for interoperability with automation equipment. This new process network has interconnected the ABB chromatograph and Fourier Transform Infrared analyzers with plant Digital Control Computers using new technology. The result was an increased reliability and capability for inspection and improved system safety

  14. Shutdown systems computer-monitoring for Cernavoda NPP

    International Nuclear Information System (INIS)

    Cernavoda Unit 1 is the newest CANDU type NPP. Fully computerised automatic control is implemented for the major unit processes including reactor regulation, boiler pressure control, unit power regulation, boiler level control, primary heat transport pressure and inventory control, turbine run-up and on-power refuelling. In order to improve post-accident diagnose and to maintain trip set-point margin during refuelling for example, a Distributed Data Acquisition System (DAS) will be implement on the actual shutdown systems configuration. Stage of selection of the equipment supplier for hardware is not completed. New Romanian PLC's manufactures have to be selected. (author)

  15. Cernavoda NPP environmental management system - tool for managing the impact on the environment

    International Nuclear Information System (INIS)

    Nuclearelectrica SA (SNN SA) is a state owned company which produces nuclear-generated electricity, heat and CANDU 6 type nuclear fuel. The company has also an active participation in the power development program in Romania. The Cernavovoda NPP, one of the SNN branches is situated at 180 km east of Bucharest, in Constanta County at about 2 km SE from Cernavoda town is a CANDU 6 type. Cernavoda Nuclear Power Plant (NPP) is dedicated to generate electrical and thermal power, safely and efficiently for at least 30 years. Having an annual gross output of 5.2 - 5.4 MWh, the Cernavoda Unit 1 NPP provides 10% of the Romanian electric power production. Starting January 01 2007, the Cernavoda Unit 1 NPP supplied into the grid 5518346 MWh electric power and during 1997 - 2007 the Cernavoda Unit 1 NPP supplied into the grid 55769213 MWh electric powers. Over the same period Unit 1 also provided the partial district heating of the town of the Cernavoda supplying about 601517.9 Gcal. Romania second CANDU nuclear power plant, Cernavoda Unit 2, was officially placed in service on Friday, October 5, 2007 together with Unit 1, the CNE-Cernavoda Station is the largest power producer in the country. It now accounts for about 18 per cent of Romania energy supply and significantly reduces its dependency on expensive energy resources from outside of Europe. It provides a structured approach to planning and implementing environmental protection measures. It also establishes a framework for tracking, evaluating and communicating environmental performance. SNN SA mission is to operate the Cernavoda NPP - in a competitive, safe and environmental friendly manner so that the production is optimized and the economic life time of the plant is as long as possible. One major accomplishment is the achievement of ISO 14001 certification for our Environmental Management System (EMS) at Cernavoda NPP. The aim of this paper is to present the EMS implemented and to emphasize the outcomes of the

  16. Cernavoda NPP impact study on terrestrial and aquatic biota. Preliminary results

    International Nuclear Information System (INIS)

    Recently, the awareness of the vulnerability of the environment has increased and the need to protect it against industrial pollutants has been recognized. The concept of sustainable development, requires new and developing international policies for environmental protection. See 'Protection of the environment from the effects of ionizing radiation' IAEA-TECDOC-1091, International Atomic Energy Agency, Vienna. As it is recommended in 'Cernavoda Unit No. 2 NPP Environmental Impact Assessment CES-03702-IAD-006', it is Cernavoda NPP responsibility to conduct an Ecological Risk Assessment study, mainly to assess the impact of nuclear power plant operation on terrestrial and aquatic biota. Long records from normal operation of Cernavoda Unit 1, wind pattern, meteorological conditions, and source terms data were used to evaluate areas of interest for environmental impact, conducting to a circle of 20 km radius around mentioned nuclear objective. The screening campaign established tritium level (because Cernavoda NPP is a CANDU type reactor, and tritium is the most important radioisotope evacuated in the environment) in air, water, soil and vegetation, focusing the interest area on particular ecosystem. Using these primary data it was evaluated which are the monitored ecological receptors and which are the measurement endpoints.This paper presents the Ecological Risk Assessment at Cernavoda NPP technical requirements, and the preliminary results of evaluating criteria for representative ecosystem components at Cernavoda NPP. (authors)

  17. Training needs analysis at Cernavoda NPP - Romania

    International Nuclear Information System (INIS)

    The paper is mainly on training needs analysis applied at Cernavoda NPP and will outline the Cernavoda (CNPP) approach in establishing what kind of training is necessary for CNPP employees, from the moment they are hired until they become qualified. The training methodology adapted at CNPP is one which adheres to the principles of the Systematic Approach to Training (SAT). SAT adoption at CNPP provides a broad integrated approach emphasizing not only technical knowledge and skills but also human factors knowledge, skills and attitudes. The analysis of SAT at CNPP consists of a 'table-top' analysis of training and qualification requirements. This paper will illustrate how a 'table-top' analysis by Subject Matter Experts is organized, carried out and recorded, and which categories of staff have begun this table-top analysis at CNPP. It will also give an example how this analysis is done: how the tasks of each job are rated, which are the used criteria, and how to proceed with the incorporation of the tasks into initial and continuing training, as appropriate. (author)

  18. Training change control process at Cernavoda NPP

    International Nuclear Information System (INIS)

    Full text: The paper presents the process of 'Training Change Control' at Cernavoda NPP. This process is a systematic approach that allows determination of the most effective training and/or non-training solutions for challenges that may influence the content and conditions for a training program or course. Changes may be the result of: - response to station systems or equipment modifications; - new or revised procedures; - regulatory requirements; - external organizations requirements; - internal evaluations meaning feedback from trainees, trainers, management or post-training evaluations; - self-assessments; - station condition reports; - operating experience (OPEX); - modifications of job scope; - management input. The Training Change Control Process at Cernavoda NPP includes the following aspects. The first step is the identification of all the initiating factors for a potential training change. Then, retain only those, which could have an impact on training and classify them in two categories: as deficiencies or as enhancement suggestions. The process is different for the two categories. The deficiency category supposes the application of the Training Needs Analysis (TNA) process. This is a performance-oriented process, resulting in more competent employees, solving existing and potential performance problems. By using needs analysis to systematically determine what people or courses and programs are expected to do and gathering data to reveal what they are really doing, we can receive a clear picture of the problem and then we can establish corrective action plans to fix it. The process is supported by plant subjects matter and by training specialists. On the other hand, enhancements suggestions are assessed by designated experienced persons and then are implemented in the training process. Regarding these two types of initiating factors for the training change control process, the final result consists of a training improvement, raising the effectiveness

  19. Overview of solid radioactive wastes management program for Cernavoda NPP

    International Nuclear Information System (INIS)

    The Radioactive Waste Management Concept for Cernavoda Nuclear Power Plant has been established as part of Documentation of Radiation Safety Program for Cernavoda Nuclear Power Plant Solid Radioactive Waste Management - Reference Document RD-01364-RP1. The Program is based on operating experience from nuclear power facilities including CANDU Plants. It is based on operating experience from nuclear power facilities including CANDU Plants. The Radioactive Waste Management Concept for Cernavoda NPP established the general approach required for the collection, handling, conditioning and storage of solid radioactive waste while maintaining acceptable levels of safety for workers, public and environment. The concept developed ensures the necessary facilities to adequately manage solid radioactive waste from Cernavoda NPP Unit 1 and will be capable of expansion when other units will be brought into service. This concept does not address the management of spent nuclear fuel and the permanent disposal of the solid radioactive wastes. For Cernavoda NPP there were defined three types of solid radioactive waste as fallows: - Low Activity Radioactive Waste, type 1, namely, solid radioactive waste with a gamma dose rate of less than 2 mSv/h on contact with the container; - Medium Activity Radioactive Waste, type 2, namely, solid radioactive waste with gamma dose rate of 2 mSv/h to 125 mSv/h on contact with the container; - Medium Activity Radioactive Waste, type 3, namely, solid radioactive waste with gamma dose rate higher than 125 mSv/h on contact with the container. The design objectives for the solid radioactive waste management facilities are defined according to their specific characteristics. Design considerations are presented for solid radioactive waste interim storage facilities as well as the operating program and monitoring program for solid radioactive waste facility. Future plans are presented for short-term strategy including gamma improvement characterisation

  20. Perspectives on managing nuclear safety at Cernavoda NPP past, present and future

    International Nuclear Information System (INIS)

    The presentation considers the following issues: background of Romanian nuclear programme; 1990 management issues involved in Cernavoda project, nuclear safety perspectives; Cernavoda U1 operating organization today (safety related issues); good practices at Cernavoda NPP

  1. System surveillance program at Cernavoda NPP

    International Nuclear Information System (INIS)

    The system Surveillance Program (SSP) is an industry accepted practice that has evolved over a number of years to the point where it is now recognized as the optimum way of ensuring system health. The SSP at Cernavoda is based on INPO good practices. It is a team effort coordinated and monitored by the system engineer (SE) and is designed to satisfy the following general purposes: - to ensure the station is operated and maintained in such a manner to be consistent with the operating license, operating policies and principles, design intent and safety analysis assumptions; - to ensure the systems are operated and maintained in such a manner to optimize reliability while being cost effective; - to ensure that systems and equipment performance is routinely monitored and, when necessary, a diagnostic testing program and subsequent corrective actions are implemented to predict and prevent potential future degradation. The SSP as described in this document applies to all systems. For all systems benefits in terms of cost savings, reliability, environmental protection and other key results can be achieved. This program is a dynamic process which is modified and improved based on the feedback from people the experience of whom in performing their tasks is used. Since many work groups are involved in implementing this program it is important to understand that good communication, information flow and a proactive attitude of all personnel are major prerequisites in developing a successful SSP at Cernavoda NPP. The document has the following contents: 1. Introduction; 2. Program implementation; 2.1. System surveillance specification; 2.2. SE tasks to implement the program; 2.2.1. System walkdowns; 2.2.2. Review performance and maintenance history; 2.2.3. Records keeping; 2.3. Reporting methods; 2.4. Supervisory requirements; 3. Some program implementation results; 4. Conclusion

  2. Nuclear safety assessment for Cernavoda NPP Unit 1 in the case of loss of Class IV power supply with primary liquid relief unavailable

    International Nuclear Information System (INIS)

    This nuclear safety analysis is performed in order to provide the thermal-hydraulic behaviour of Cernavoda NPP Unit 1 following complete loss of Class IV power supply with primary liquid relief unavailable. The most serious consequence of this accident is the loss of all four primary heat transport pumps coincident with liquid relief valves fail to open. The transient behaviour of primary heat transport system is predicted, mainly, in order to determine coolant pressure and fuel and sheath temperature in a conservative manner, when the reactor is tripped on the latest trip signal. The values of primary heat transport system peak pressure and maximum fuel and sheath temperatures are compared with the safety limits. (authors)

  3. Cernavoda - Unit 2. A strategic project for Romania

    International Nuclear Information System (INIS)

    The paper presents some key aspects of the Romanian nuclear program, focusing on Cernavoda NPP Unit No. 2 and the partnership with Atomic Energy of Canada Ltd. (AECL) and ANSALDO Italy for completion of this project. A brief historical presentation of the Romanian nuclear program is included. The success of Cernavoda NPP Unit 1 represents an important element in finalizing Unit 2 in an advanced state of equipment installation and more than 40 % complete. Also, the national infrastructure, including the legal framework and new Electricity Law represents a positive element for Project completion. The Romanian Nuclear Regulatory Body represents the guarantee for the safe operation of CANDU reactors in Romania.(author)

  4. Tritium bearing molecular sieves from NPP Cernavoda

    International Nuclear Information System (INIS)

    Full text: Drying towers packed with molecular sieve beds are used to retain tritiated heavy water resulting in Cernavoda NPP current operation, which has leached from various parts of the reactor systems, in order to recover and reduce heavy water loses and to minimize tritium contamination. Molecular sieve during operation are put through cycles of adsorption and regeneration, in fact a desorption phase, and have a lifetime of several hundred cycles adsorption-desorption. After sending their life time the molecular sieves become tritium bearing radioactive wastes and have to be dealt with accordingly. The present paper will briefly describe the current practices for molecular sieve conditioning prior to disposal and the requirements for the conditioned radioactive wastes. Also, the paper presents the development of the conditioning technology for the tritiated molecular sieve capable of realizing a product which matches the waste acceptance requirements imposed by the National Authority for Control of Nuclear Activities, CNCAN, for the disposal at the DNDR Baita - Bihor national repository . (authors)

  5. Management of occupational exposure at Cernavoda NPP

    International Nuclear Information System (INIS)

    Ionising radiation presents a particular risk associated with nuclear power plant operation. An effective and efficient radiation protection program should: - prevent the detriment of health due to deterministic effects; - keep all the exposures as low as reasonably achievable in order to limit the detriment of health due to stochastic effects; - provide safety and health conditions as good as other safe industries. Radiation protection of occupationally exposed workers is part of Health and Safety of Work Program. Effective dose limits, as recommended by ICRP and required by CNCAN regulations are reasonably low in order to avoid deterministic effects and to limit the probability of stochastic effects to an acceptable level. The health status of Cernavoda NPP employees is appropriately surveyed. There were not recorded cases of occupational diseases and/or other indicators of relevant biological effects in order to establish the specific response of the human body to the occupational illness risk factors. Starting in 2002 the cytogenesis blood analysis for occupationally exposed individuals was performed at the beginning of their employment and then periodically for those working for more than five years in the plant. Up to 1900 employees have been investigated with no indication of genetic modifications. (author)

  6. Full scope simulator commissioning and training experience at Cernavoda NPP

    International Nuclear Information System (INIS)

    The paper presents the experience gained during commissioning and the initial use of the CANDU training full-scope simulator for operation personnel at Cernavoda NPP. The full-scope simulator as an integral part of the training programs that take place in Cernavoda Nuclear Training Department (CNTD), is mainly used for the development of operational skills, knowledge and attitudes required to operate the plant in a safe and efficient manner. (author)

  7. Management of maintenance activities at Cernavoda NPP

    International Nuclear Information System (INIS)

    After the Construction and Commissioning phases are over, the safety and economic performances of each nuclear unit are determined by the quality of its operation as well as by the combination of reliability and availability of the systems consisting the whole unit. Therefore, the value of a good maintenance program in making a safe and profitable operation is now widely recognized; all stations operating with excellent performance have well-defined policies and effectively administered programs to govern maintenance activities. The Cernavoda maintenance optimization initiative is derived from good practices suggested by such recognized bodies as the IAEA, INPO and EPRI. It should be noted that the program is evolving at this time and that this paper is an attempt to summarize the myriad of activities and plans required to finally implement the maintenance program. Although many of the elements of the program are in place, many are in various stages of completion. The main components of the program (policy's objectives, strategies used, specific subprograms, maintenance plans and their integration) are presented in brief along with the performance indicators used to assess the effectiveness of the program and maintenance activities. The new programs intended to be developed are also specified, as well as the main comments and recommendations received from IAEA experts. (author)

  8. Appendix III: Cernavoda Nuclear Power Plant: Phased implementation of similar units - Human resource management and training programmes (Romania) (Case study of human resource issues faced by NPP operating organizations, and how they were (or are being) addressed)

    International Nuclear Information System (INIS)

    Nuclear power generation is a reliable source of energy for Romania and an important contributor to the national electricity supply. Romania has one nuclear power plant, Cernavoda, which operates one CANDU 6 reactor, 707 MW(e), designed by Atomic Energy of Canada Ltd (AECL). Provides about 10 percent of the total country energy consumption. The state-owned company responsible for the production and supply of energy from Cernavoda NPP, as well as for its development, is Societatea Nationala 'Nuclearelectrica'. The plant was designed to have five similar units. The studies performed for the plant, prior to the construction's start, established feasible technical solutions for all problems related to a 5-unit site, including the environmental impact, which would be entirely acceptable. Construction of the first unit started in 1980 and of units 2-5 in 1982. The pressing problems encountered during construction of Unit 1 (import restrictions, delays etc.) restrained the progress at Unit 2. Starting with 1990, the work on Cernavoda site was focused on Unit 1 and the construction at the other units was suspended. Since then, only preservation activities have been carried-out. The re-start of work at Unit 2 took place in 1995, under the management of the AECLANSALDO Consortium. Some construction work was carried-out (e.g. installation of the fuel channels) and a thorough assessment was performed concerning the condition of the equipment procured for Unit 2 and stored on site, or already installed. The absence of a clear contractual framework and the lack of resources hindered significant advance in the construction of Unit 2. Since then, many economic estimates foresee that, starting with winter 2005 when Romanian electricity consumption is expected to increase with about 1000 MW(e), the annual electricity production will become insufficient and will be not covered unless Unit 2 of Cernavoda NPP is commissioned. In this environment and considering the relatively low cost

  9. Cernavoda NPP U1 environment management as a support element in promoting durable development concept

    International Nuclear Information System (INIS)

    The first unit Cernavoda NPP, commissioned on December 2, 1996, with an installed power of 706,5 Mwe, became the most important unit of the Romania's national power system. Since the first year of operation, Unit 1 from Cernavoda contributed with 10 % from total amount of electricity produced in Romania. The NPP Cernavoda reached in last years of operation a high rate of using installed power, around 88-90%. The contribution to this high capacity factor is provided by high quality of the installed equipment, competence in performing operational activities, and correct conduct of operation. Therewith, plant operation is done in accordance with a Quality Assurance Program, based on written procedures in order to ensure that technical, nuclear safety, environment and industrial safety requirements are strictly observed. SNN imposes to Cernavoda NPP a development and implementation of an environment management system in accordance with ISO 14001, a system which was certified in 2003. The Environment Management System developed as per above standard requirements was integrated in the QAP applied to Cernavoda NPP. Based on this policy the following general objectives related to environment were established: 1) to continue improvement of the quality of the environment factors in order: - to maintain the release limits for all types of effluents below the limits imposed by authorization; - to minimize the chemical and radioactive pollution in the area of the NPP. 2) to improve the population protection level, by maintaining population doses at ALARA level. 3) to develop a radioactive waste management in compliance with the best practices in the EU countries, and taking into consideration the evolution of the national legislation, EUC and IAEA recommendations by: - including the spent fuel dry storage intermediate facilities in the radioactive waste disposal system; - minimizing radwaste volumes at source; - minimizing radwaste volumes designed to final storage. 4) to

  10. Elements and strategies of Knowledge Management at Cernavoda NPP

    International Nuclear Information System (INIS)

    The paper highlights that there are Knowledge Management (KM) elements already implemented at Cernavoda NPP, ensuring the safe operation of the plant. The KM process is not formalized yet, but the following elements are part of existing KM practices for Cernavoda NPP organization: Plant policies and procedures are in place; Document control is in place using Document Management system; Configuration management is a complex and well structured process; Training and qualification is based on SAT; Learning from operating experience internal and external is a day by day practice, (procedures, PJB, PROEM, Simulator, RCA, Training, etc.); Work control system is implemented via Ventrix Work Management System; Corrective action tracking is implemented; Workforce planning and human resources management is a continuous process; Communications are implemented by the plant personnel; Company intranet and other web-based solutions (CBT) are put in place; Human performance improvement programme is on going. Also, it is reinforced the need to develop and implement a structured knowledge transfer and retention process for the Cernavoda NPP in order to preserve unique knowledge and skills that could be lost through attrition or planned staffing changes. (author)

  11. Radioactive waste management at Cernavoda NPP after 5 years of experience

    International Nuclear Information System (INIS)

    Many human activities generate waste but people are worried about those produced in nuclear power plants. Their concern is an unjustified fear toward the hazard from radioactive wastes because any country, which produces electrical power in this way, pays a lot of attention of all relevant parties involved in radioactive waste management. The same policy is applied for Cernavoda NPP. Our concept establishes the general approach required for the collection, handling, conditioning and storage of radioactive waste from Cernavoda NPP Unit 1 and will be ready for expansion when other units are brought into service. Among others, a major objective is to reduce the radioactive waste production and volume. In this regard we are trying to improve as much as possible our procedures and radioactive wastes management. Further, it will be presented the radioactive waste management, including the improvements in our program and the future plans.(author)

  12. Environmental radiological impact of Cernavoda NPP operation

    International Nuclear Information System (INIS)

    The release of any potential radioactive pollutant to the environment during routine operation of a Nuclear Power Plant should be the subject of appropriate controls and assessments. It is impossible to monitor directly the dose contribution of normal releases because the environmental radioactivity levels are very small but source monitoring provides a means of assessing the radiation exposure of population groups, critical groups and individual members of the public. Derived emissions limits ( DELs ) are used to quantify the relationship between releases of radioactivity and doses to public - critical groups. CNE-PROD DELs are based on a pathway analysis conducted for Cernavoda site specific conditions and they were computed using a compartment transfer model. Annual air and water emissions for the most significant radionuclides between 1996 and 2000 are presented in terms of %DELs and can be observed that population doses are far below the authorized limit and negligible in comparison with average annual population dose from natural sources. (authors)

  13. Modelling the impact of Cernavoda NPP on the environment

    International Nuclear Information System (INIS)

    In connection with a stay as a visiting researcher at VTT Energy (Technical Research Center of Finland), a study was conducted related to the atmospheric dispersion and dose assessment for radioactive releases from nuclear power plants. The most important aspects of this study are described in this paper. These include: the application of the TRADOS dispersion and dose assessment model in the case of the Cernavoda NPP and the development of a special program INTEGRATION for the calculation of cloud gamma dose rate of 72 nuclides. (authors)

  14. Ageing of electronic equipment used in Cernavoda NPP

    International Nuclear Information System (INIS)

    This paper presents some ageing mechanisms and an evaluation of systems and electronic equipment from Instrumentation and Control (I and C) system, taking into account their importance in command, control and safety operation of NPP. Concepts regarding lifetime, single and multiple stresses, experimental evaluation methods of lifetime, evaluation norms, measurement methods and constraints of lifetime evaluation techniques are also presented. The analysis highlights the factors that influence the operational safety, improvements in the methods of design, manufacture and operation, typical causes of failures and a case study on ASFD modules (Amplifier for Flux Detectors Self-supplied). In order to create a data base regarding the behaviour in time of modules and equipment in similar conditions as those of Cernavoda NPP, measurements of the operational parameters, without input current and with injection of current, depending on the type of module designed for each type of detector self-supplied (with vanadium or platinum ) were carried out. (authors)

  15. Cernavoda NPP: Training for safety and reliability

    International Nuclear Information System (INIS)

    The safe and reliable operation of NPP require successful integration of plant and system design (1), programmes and procedures (2) and qualified human resources (3). Of these three components, station personnel and management have capability to influence and improve programmes and competence of qualified personnel. Qualifying personnel includes selection, training and evaluation that meet the established performance standards. Training, therefore prepares people to achieve such competence. The critical role of operations personnel has been rightly emphasized by every country with a nuclear power programme. So far as operation team is concerned, they have to work, on the one hand with exacting safety rules and at the same time, they have to do the right thing at all times. In essence, they have to be prepared for new, emergency situations as well as for routine work. The plant operation in the Control Room is essentially a man - machine interaction and a safe and reliable operation requires them to take high quality decisions even under stressful conditions. Here lies therefore the need for high competent and licensed operations engineers who will ensure operation within the operating license of the station under the all conditions. The development of a long-term comprehensive training for Operation Staff is a requirement. The program addresses the qualification requirements of the various nuclear positions on shift, the outline content of the required training programs and the evaluation per the Systematic Approach to Training (SAT). A nuclear operator's training begins the moment he/she enters the station. It takes four to six years to develop the skills required to demonstrate that the candidate is an appropriate choice for the position. Then there's a further about two years of intense training at the Training Center on a simulator. After successful completion of the program, the candidate is authorized by the CNCAN (National Commission for Control of Nuclear

  16. Cernavoda NPP integration in the Romanian grid

    International Nuclear Information System (INIS)

    The intention of this material is to present our point of view about some specific matters that arise from having a relatively large power production unit (706 MW) connected to a National Grid in which the second largest units are only 330 MW. The material consists in three major parts. In the first section is presented the 'big picture' of the Romanian National Grid. The second section covers the role played by CNPP in the grid power balance and frequency/voltage adjustment. CNPP is located at the base of the daily load curve and thus not normally participating at frequency adjustment. CNPP also has a contribution in increasing the dynamic stability of the National Grid. The third section is a more detailed presentation of CNPP behavior during grid upsets, with reference to the reactor and turbine control systems, and also the types of transients that our plant could induce to the grid due to internal malfunctions. The over-all unit control is based on the 'reactor power constant' policy, all the fluctuations in the power output to the grid being compensated by the Boiler Pressure Control System. Some features of the Turbine Electro-Hydraulic Control System and how it interacts with the Boiler Pressure Control Sys. will also be presented. The types of transients that CNPP could experience are reactor power setbacks (automatic ramped power reductions), reactor power step-backs (fast controlled power reduction) and unit trips, which are the most severe. There are two ways from the grid point of view to deal with such transients; to compensate the power loss by increasing the production and to disconnect unimportant power consumers. These actions are taken both automatically and manually (some details will be presented). (author)

  17. Noble Gases Monitoring In Gaseous Effluents at Cernavoda NPP

    International Nuclear Information System (INIS)

    The main objectives of effluents monitoring programs, are to limit releases of radioactivity to the environment so that the exposures are not likely to exceed dose limits established by the competent authority and to provide reasonably assurance that the levels of radioactivity added to environment are well below levels that could result in adverse effects on the ecology of the environment. The Gaseous Monitoring System installed and commissioned in Unit 2 of Cernavoda NPP is a modern and reliable equipment that allows an accurate monitoring of the atmospheric emissions for assuring the control of releases and for comparison with the limits established by the authorities. Also, having the benefit of using measurement features like on-line monitoring (through Radiation Monitoring System), on-line -spectrometry with NaI detection system and supplementary γ - spectrometry with HpGe detector, the system allows to identify the activities of the plant that can lead to significant radiological impact regarding the levels of emissions and their magnitude (e.g.: Annulus Gas System purges, PHT Storage Tank purges, defective fuel removal, maintenance work on active systems). One of the most significant applications of the Noble Gases Monitoring Channel at Unit 2 is represented by the monitoring of the gaseous emissions during and after the removal of the fuel suspected to be defective. On-line surveillance of the noble gases emissions was performed to prevent the attaint of the alarm set - point and to reduce, as much is possible the levels of radioactive releases. By taking in account the total activity previously released, the real - time emissions rate and trend evolution, it was established if the criteria for the manual isolation of the Containment System (Reactor Building Boxed-Up) are fulfilled or not. The γ - spectrometry with NaI and HpGe detection systems allowed to identify the components of noble gases nuclides mixture present in the discharges and inside of the

  18. Operator refresher training and requalification at Cernavoda NPP

    International Nuclear Information System (INIS)

    The paper presents the Operator's training program for refresher and requalification purposes, which were developed using the CANDU training full-scope simulator at Cernavoda NPP. First the purpose of both programs is described, and then more details on how these programs are delivered are given. The Refresher Training Program, part of the Operator Continuing Training Program, and the Requalification Training Program are periodically training given to the previously authorised operating personnel. The training and the evaluation are conducted both on an individual and on the team basis. Both programs are tailored according with Systematic Approach to Training concept. In addition to that the importance of the training on simulator arises from the fact that the training is mostly related to plant transients/accidents that in real life may never happens, but the operators should be always prepared for the worst. Continuing Training Program (CTP) applies to the authorized positions of Shift Supervisor (SS) and Control Room Operator (CRO) at CNE-PROD Cernavoda. Also, the program is establishing the criteria and the process, which will allow the authorised SS and CRO to maintain their authorised status. (author)

  19. Public doses due to tritium emissions from Cernavoda NPP

    International Nuclear Information System (INIS)

    Heavy water reactors have a large tritium load. In a CANDU reactor most of the tritium is formed in the thermal-neutron-capture reaction, 2H(n,γ)3H which occurs both in the moderator and heat transfer system. Very small amounts of tritiated heavy water may escape from moderator and heat-transport systems of CANDU reactors during maintenance and normal operation. Tritium emissions of Cernavoda NPP were continuously monitored. The tritium concentrations in environmental samples were monitored as part of routine program and public doses were calculated. This paper presents the supplementary tritium doses for a member of public, estimated using HTO concentrations in environmental samples and OBT doses estimated based on Candu Owners Group studies 'OBT/HTO Ratio in plants' and 'Contribution of Organically Bound Tritium to total Tritium Dose'. (authors)

  20. Elements regarding the seismic hazard at NPP Cernavoda

    International Nuclear Information System (INIS)

    The paper presents the basic elements for evaluating the seismic hazard by probability methods at a nuclear power plant and the preliminary results obtained by the authors for NPP Cernavoda site. The analyses had in view the historical and instrumental seismic events covering the period 984-1990. Student and Fisher tests applied to the set of the data corresponding to this period showed that the data set did not meet the requirements for statistical interpretation. For that reason the set of data which was considered included only the earthquakes having magnitude higher than 5 which satisfy the homogeneity tests, as well as the earthquakes grouped in 5 year intervals that satisfy Student and Fisher tests

  1. The assessment of the waste management plan to decommissioning of Cernavoda NPP for environmental impact reduction - 59358

    International Nuclear Information System (INIS)

    Most of the radioactive wastes generated in Romania, are due to nuclear activities related to power generation at Cernavoda Nuclear Power Plant NPP Unit 1 and Unit 2. It is provided to construct 2 new Units, in the next period. In Romania, the Nuclear Agency and Radioactive Waste - AN and DR, has established the strategy on low and intermediate level waste disposal and has as objective the commissioning of Final Repository for Low and Intermediate Level Waste - DFDSMA, until 2019. This facility, is in the responsibility of AN and DR. On the other hand, wastes arising from Cernavoda NPP must be treated, in order to achieve the acceptance criteria of DFDSMA. Corresponding Radioactive Waste Treatment Plant - RWTP is in the responsibility of Cernavoda NPP. The main requirement for the RWTP is the necessity to achieve the treatment and conditioning of radioactive wastes that arise both, from NPP operation and from future decommissioning activities of the nuclear facilities, such as to comply with the acceptance criteria of DFDSMA. According to existing requirements, it is necessary to elaborate a Decommissioning Plan, in order to obtain the authorization for construction of the new units. The Decommissioning Plan of Cernavoda NPP will imply the development of a Waste Management Plan, based on existing waste treatment technologies. Taking into account that, the radioactive waste management represents about 43%, comparative with decommissioning activities, which represents only about 35% from total budget of decommissioning, of a CANDU 6 NPP Unit, the paper will present the methodology developed, in order to obtain the optimum Waste Management Plan, taking into account the reduction of environmental impact. (authors)

  2. Status of the spent fuel dry storage programme for Cernavoda NPP

    International Nuclear Information System (INIS)

    The Cernavoda NPP Unit 1 (600 MWe Standard type) is in operation since December 1996. Within the framework of the R and D Radioactive Waste and Spent Fuel Management Programme, investigations, studies and research are carried out on site identification and conceptual designs for both a Spent Fuel Interim Storage Facility and a Spent Fuel Disposal Facility. The status of the work performed in the framework of this programme as well as the situation of the spent fuel resulting from the Research Institutes will be presented in the paper. (author)

  3. CITON solutions for introducing distributed control system in nuclear steam supply systems at Cernavoda NPP

    International Nuclear Information System (INIS)

    Cernavoda NPP - Unit 2 Project implemented the Distributed Control System (DCS) into a series of systems where the Nuclear Steam Supply Systems (NSSS) were not included. Hence, in this paper, CITON designers place a particular emphasis on developing a methodology to introduce DCS preserving the nuclear safety basis. This approach consists of two applications implying instrumentation hardware and software upgrade. The first application is a way to transfer into modern technology the functions of the Main Moderator System (MMS) human-machine interface (HMI), while the second one introduces an on-line control, diagnosis and monitoring system, for Primary Heat Transportation System (PHTS). (authors)

  4. Low and medium level solid waste management for final storage in NPP Cernavoda

    International Nuclear Information System (INIS)

    The NPP Cernavoda will consist of five 600 MW(e) CANDU type reactors, which are now in various phase of construction. Unit 1 is in use from 1996. Although each reactor is provided with adequate facilities for intermediate storage or controlled discharge of all solid, liquid and gaseous wastes, plant operation will generate significant quantities of low and medium level solid wastes, so that the problem of their final storage must be solved as soon as possible. For that purpose, a programme is in progress to support the development of the final storage strategy, that meets applicable nuclear safety requirements for human population and the environment. According to this strategy, the construction of a near surface final repository, where a treatment and conditioning plant was included, is planned for 2003-2005. For this repository, the Saligny site, near the NPP, inside the exclusion zone was chosen. The final storage capacity (approximately 60,000 m3), which is to be built in steps, should be enough to accommodate all low and medium level solid wastes resulting from a minimum 30 years of operation of each reactor and from decommissioning. This paper presents how the low and medium level solid wastes that result from operation shall be managed for final storage in the NPP Cernavoda. (author)

  5. The Romanian experience on introduction of CANDU-600 reactor at the Cernavoda NPP

    International Nuclear Information System (INIS)

    The Cernavoda Nuclear Power Plant (NPP) Project is a key component of the Romanian nuclear development program. Selection of the CANDU design represents a major contribution to this development, due to the technological feasibility for manufacturing of parts, components and the nuclear fuel based on the uranium resources in Romania. The Romanian nuclear development program also involves a nuclear fuel manufacturing plant, a heavy water production plant and organizations specialized in research, engineering, manufacturing and completion for systems and components. The agreement on technological transfer between Canada and Romania is supporting the Romanian involvement to the achievement of the Project, with a degree of participation that is gradually increasing from the first to the last NPP Unit. (author)

  6. Contributions of INC-DTCI from ICSI Rm. Valcea to Cernavoda NPP's progress

    International Nuclear Information System (INIS)

    Development of Romanian Nuclear Programme was the basic objective of our institution, 'G' plant - Rm. Valcea at present the National Institute of Research-Development for Cryogenics and Isotopic Technologies. Initially constituted as an experimental pilot for developing the technology of heavy water production, a task solved and later transferred to the newly created ROMAG Heavy Water Plant, our institution collaborated to the technical project of heavy water reconcentration at Cernavoda NPP Unit 1 as well as to reconcentration of moderator and coolant facility. The objective of these two installations was to guarantee a as high as possible isotopic purity of the moderator and coolant and thus to reach a high burnup coefficient of natural uranium in the CANDU reactor. The main contributions in the stage of construction of the D2O reconcentration tower were the following: elaboration and patenting of phosphorous bronze; designing the ordered packing of phosphorous bronze with 800 mm diameter; preparation of phosphorous bronze packing; elaboration of activation/reactivation technologies for obtaining phosphorous bronze packing; preparation of column sections, internal equipment for their mounting, etching and passivation; activation of potassium permanganate packing; mountain g the activation packings in the column sections and their passivation; designing and construction of heavy water analyzers; realization and certification of heavy water control samples for the entire concentration range; supplying of heavy water of nuclear quality. In collaboration with Cernavoda NPP for tritium extraction from heavy water a detritiation facility has been developed. Romania is participating also to European and international fusion programs

  7. The licensing process of Cernavoda NPP interim spent fuel dry storage

    International Nuclear Information System (INIS)

    The first 12,000 spent fuel bundles capacity of a new modular interim spent fuel dry storage facility is in operation at the Cernavoda NPP site, since May 2003. The facility consists of a preparation station, a shielded transfer flask and a concrete monolith module of the MACSTOR type, a system designed by Atomic Energy of Canada Limited. The capacity can be extended to accommodate 300 000 spent fuel bundles, which represent the entire production of spent fuel during the lifetime of two CANDU-6 units. The project was implemented by Nuclearelectrica based on the licenses and permits granted by the National Commission for Nuclear Activities Control (CNCAN) for each step: the siting, construction, commissioning and operation. According to the specific Romanian regulations, the interim dry storage facility is also subject to the licensing process by the Environmental and Public Health authorities. The public involvement has been an important step of the environmental licensing procedure. Cernavoda NPP used different legal procedures for the public debate, including announcements in local and national newspapers and public hearings. No objections against the storage facility have been raised. (author)

  8. Cernavoda NPP feedwater system transient analysis using MMS package

    International Nuclear Information System (INIS)

    In this analysis we studied thoroughly the operation of the Feedwater System with purpose of preparing of a simulator as complete as possible for Candu 600 nuclear power plants, particularly for Cernavoda NPP. We made a complete simulation for the feedwater system because we intended to study all functional regimes of the system. We considered as boundaries of analyses the following: - Main Condenser System - deaerator; - Feedwater nozzle from Steam Generator; - Outlet nozzles from steam turbine to regeneration preheaters; - Secondary Drain thermal drain cycle. The computational codes used in this analysis are PIPENET and MMS. The following types of analyses were carried out: - hydraulic analysis for stationary regimes - 100% MCR (Main Continuous Rate), 80% MCR, 60%MCR with 2 Main Feedwater Pumps working, 60%MCR with 1 Main Feedwater Pump, 40%MCR. Those analyses were done using hydraulic package called PIPENET; - thermal hydraulic analyses; - stationary regime of 100%MCR using as starting point data resulted form PIPENET; - transient regimes starting from nominal values regime and various boundaries conditions. Transient regimes analyzed in this work are: all normal functional regimes of Feedwater System according with Design Manual; all abnormal regimes of Feedwater System without accident regimes. For all thermal hydraulic analyses we used MMS package. The results obtained with this MMS package were compared with data from heat-balance calculated of stationary regimes (100%, 80%, 60%, 40%) provided by General Electric - turbogenerator supplier

  9. The systematic approach of preserving environmental qualification at Cernavoda NPP

    International Nuclear Information System (INIS)

    This paper describes the methodology used for preserving Environmental Qualification (EQ) of the Components and Equipment for the Safety Related Systems at Cernavoda Nuclear Power Plant - Unit 1 (a CANDU Project). Environmental Qualification is the process of generating and maintaining of evidence that safety related equipment is capable of performing its safety function during and following a Design Basic Accident - DBA - (LOCA - Loss of Coolant Accident/MSLB - Main Steam Line Break) inside the Reactor Building. The major parts of this presentation are as follows: basic EQ Concepts; methods of Qualification; environmental Conditions (Mild/Harsh Environment); EQ Program: EQ Maintenance Program; EQ Equipment Walkdown; control and Monitoring of the Procurement; control and Monitoring of the Shelf Life. (author)

  10. Probabilistic determination of neutronic trip setpoints at Cernavoda NPP, Romania

    International Nuclear Information System (INIS)

    This paper describes the methodology used for probabilistic determination of the Regional Overpower tripsetpoints at Cernavoda Nuclear Power Plant Unit 1 (a CANDU project). The shutdown systems use in-core flux detectors to protect against local power increases that can lead to fuel dryout and melting. These flux detectors are spread throughout the reactor core and are assigned to 3 independent trip channels per shutdown systems. The design criteria is that each shutdown system must trip the reactor with a confidence of 98% on a 2 of 2 logic, i.e. assuming the best trip channel unavailable. Parameter considered in the calculation of the trip-setpoints (TSP) are affected by random and systematic error. The probabilistic approach described here was developed by AECL specialists and allows error margins of ∼ 10%, lower than the deterministic margin of 15-20%.(author)

  11. Estimation of radionuclide releases in atmosphere from Cernavoda NPP based on continuous gaseous effluent monitoring

    International Nuclear Information System (INIS)

    Monitoring of gaseous effluents from Cernavoda NPP is performed to assess the environmental impact of the plant operation. The results of the monitoring program are used to evaluate the population doses in order to ensure that the emissions of radionuclides in air are below regulatory limits and radiation doses are maintained ALARA. It complements, but is independent from the Operational Environmental Monitoring Program for Cernavoda NPP. Gaseous effluent monitors provide continuous indication of the radioactivity content in atmospheric emissions. Except for noble gases, these monitors also collect samples for later detailed analysis in the station Health Physics Laboratory. This paper presents the main equipment and the results of the gaseous effluents monitoring program in order to assess the impact of Cernavoda NPP operation and to predict the future releases as function of radionuclides concentrations in CANDU systems, based on the identified trends.(author)

  12. New issues in radioactive waste management legal frame and challenges for CNE-PROD Cernavoda NPP

    International Nuclear Information System (INIS)

    This paper presents national legal frame governing radioactive waste management activities (including spent fuel), legislative newness, introduced during last two years, current status of radioactive waste management at CNE-PROD Cernavoda, as radioactive waste main producer and associated responsibilities and derived actions for CNE-PROD radioactive waste program. Romania has only one nuclear power plant, Cernavoda NPP, equipped with five PHWR - CANDU-6 Canadian type reactors - with a 700 MW(e) gross capacity each, in different implementation stages. Unit 1 is in commercial operation since December 2, 1996, Unit 2 is under construction and Units 3, 4, 5 are under preservation. Spent fuel management facilities at CNE-PROD consist of Spent Fuel Bays and The Intermediate Dry Spent Fuel Storage facility. Radioactive waste management facilities at CNE - PROD consist of Solid Radioactive Waste Interim Storage Facility. Objective of Romanian radioactive waste management policy is to assure safe management of radioactive waste, according to the principles stated in IAEA SS No. 111-F. The Romanian radioactive waste management policy and strategy are fully taking into account the general and radioactive waste management specific IAEA requirements. New legislative issues from last two years establish clear responsibilities for the different institutions involved in the different steps of spent fuel and of radioactive waste management. (author)

  13. Reliability problems in the recirculated cooling water system at Cernavoda NPP and corrective maintenance operations adopted

    International Nuclear Information System (INIS)

    Between February 18 and March 5, 2002 the Unit 1 of Cernavoda NPP was shutdown in an un-planned outage necessary to repair a crack on the piping of the Recirculated Cooling Water System. The large pipe diameter and the requirement of maintaining the system in operation during the outage, imposed a special technology for fixing the leak (isolation of the line with ice plugs). The paper presents information about the performed repair work. After repair operations the failed duct was checked by non-destructive methods and the results were submitted and approved by regulation authorities. The repair was considered successfully completed and the Unit restarted on March 5, 2002 at 0.57 am when the electric generator was switched on in parallel to the national electric power system. (authors)

  14. Automatic control of the D20 vapor recovery dryers at Cernavoda NPP U2 (CANDU Project 82)

    International Nuclear Information System (INIS)

    The 'D20 vapor Recovery System' is built in the frame of CANDU NPP Cernavoda, Romania, in order to preserve the atmosphere dry inside the Reactor Building. The system includes ten dryers, four tanks and three pumps grouped in thirteen equipment units with cyclic operation. When desiccant bed of the dryers is full of humidity the operating regime is switched automatically from absorption to regeneration. During regeneration, the air from blower discharge is passed through electric heaters and desiccant bed to condenser where the D20 vapor is recovered, and again to fan inlet. The dryer regeneration is completed when its desiccant bed is hot. Also, transferring the contents of the tanks is a batch processing operation. Considering the Cernavoda U1 operating experience, the CANDU project 82, for Cernavoda NPP U2, is now under an improving process, which implies an Automatic Control for the 'D20 vapor Recovery System'. This Automatic Control, performed by Industrial Computers and Data Acquisition System, is able automatically to detect the completion of the equipment unit phases, to switch the equipment unit to appropriate operation mode, to check the proper operating mode and to trip the equipment unit if necessary. This paper intends to present the problems surmounted during the technical specification issuing for designing process. (author)

  15. Annx IV. Delayed nuclear power plant project management experience Cernavoda 2 NPP, Romania

    International Nuclear Information System (INIS)

    The Cernavoda Unit 2 NPP work was originally started in 1982 with work coming to a halt in 1989, and a preservation program implemented in 1991 while work continued on Unit 1. In 1995 attention turned to the completion of Unit 2 and status verification reports were commissioned. Work proceeded, as funds were available, up until 2002 when an interim contract was signed. Subsequently a Contract Completion Effective Date (CCED) was signed in March 2003 with completion duration of 48 months. A project schedule is a necessity for any project whether it is a new build or a restart to a delayed project. There are 5 major elements that are included in all CANDU project schedules, Engineering, Procurement, Construction, Commissioning and the conversion from Construction to Commissioning. The Engineering schedule of deliverables was not fully defined at CCED. Design changes defined prior to CCED were not fully defined and the scope of work associated with these only became known during the actual construction program. A significant number of new design changes were introduced after CCED, which compounded the impact to the construction program. All projects require their budgets to be built up within a defined structure. Delayed projects are no different from other projects in that respect. The standard Work Brakout Structure (WBS), which is applicable to most CANDU projects, is equally applicable for a delayed project. On Cernavoda Unit 2 we used a Budget Breakdown Structure, which was a combination of a traditional WBS and an Organization Structure. This structure was adopted in order to have consistency with the structure, which had been used prior to the delay on the project and also it was a requirement of the three party agreements with funding from different sources and in different currencies. All major construction projects normally carry a contingency allowance for undefined work and a risk allowance for the possibility of major changes. Delayed projects require

  16. Occupational exposure to external ionising radiation: Personnel monitoring and dose evaluation at Cernavoda NPP

    International Nuclear Information System (INIS)

    Cernavoda NPP has two CANDU 600 reactors in commercial operation. For a CANDU reactor the major contributor (95%) to the external dose is gamma radiation. Individual dose monitoring is provided by an accredited dosimetric service, approved by the Romanian regulatory body (CNCAN) at CNE Cernavoda. For all the persons entering radiological controlled areas Health Physics Department provides individual dosimetric surveillance. When entering / working in areas where approved dose rates could be exceeded, beside TLD, an electronic direct reading, a personal alarm dosimeter (PAD) is used. When entering / working in areas with significant neutron dose rates an integrating portable neutron monitor is used. The main purpose of design and implementation of an Individual Dosimetry Program is to measure, assign and record all the significant radiation doses (Hp(10), Hp(0.07) and E50) received by an individual during activities performed at CNE Cernavoda NPP and ensure that all the exposure are kept under ALARA prescriptions. (authors)

  17. Estimation of the future nuclear power research in Romania, based on the present Cernavoda NPP evolution

    International Nuclear Information System (INIS)

    For more than four decades, the electric power needs of Romania were evaluated on the basis of the State Plan for Economic Development. To identify the optimal solution, the 'least price per produced MWh' was practically the only criterion. Now, there is no convincing estimation of the future economic development and at least two additional criteria play a significant role, 'the safety in the supply of the needed electric power', and 'the need of limiting the environmental impact of electricity generation'. The analysis dedicated to evaluation of future electric power solutions must take into account several features of the present situation. There are no available internal funds to finance the construction of new generating units of the order of several hundreds of MW. Even the so-called 'refurbishing' of the existing thermal power plants is based on foreign loan. In the 2000 year, about 80 electricity generation units reached 30 years of operation, i.e., the design life. Other thermal power plants proved very modest performances during 15-20 years of operation. Consequently, the future of almost 100 generating units is either in shutdown + decommissioning or shutdown + modernization situation. The Government analyzed the situation and decided to continue the completion of the Cernavoda NPP. The Unit 2 will be commissioned in a couple of years, and there is a schedule of negotiations relating the future of the Unit 3. After almost five years of successful operation of the Unit 1, the collaboration between RDT Institutes and NPP has clear features. Based on the experience related to this collaboration and taking into account the evolution of the Cernavoda NPP, we estimated that five research domains have significant chances to obtain a stable (and, hopefully, consistent) financial support. 1. Nuclear Safety, in particular Accident Analysis. As the Government re-iterated the firm decision to meet the conditions required for European integration, most of the nuclear

  18. Are the seismic design accelerations for Cernavoda NPP site representative or not?

    International Nuclear Information System (INIS)

    Is the Design Seismic Acceleration for CANDU 600 PHWR in Romania representative or not for Cernavoda site? Is the value of 0.2 g determined for DBE providing a sufficient safety margin through the entire Cernavoda NPP life span? To the above questions a substantiated answer can be offered by the elaboration of the Seismic Hazard Analysis which should consider: the historical seismic data and instrumental data, the geologic and seismic-tectonic structure, the detailed mathematical models, various specialist opinions, numerical and procedural errors, etc. Probabilistic Seismic Hazard Analysis (PSHA) is a methodology that estimates the annual probability to exceed various levels of a ground motion parameter (Peak Ground Acceleration - PGA, or the ground Acceleration response Spectrum, Sa), as a result of a seismic activity generated in all focuses that affect a given site. On basis of the analyses and studies elaborated for Cernavoda NPP site area, it results that the seismic sources which may affect Cernavoda NPP site are: Vrancea-intermediate, Vrancea-normal, Sabla-Dulovo, Galati-Tulcea and the Local earthquakes. The Seismic Hazard Analysis performed by CITON Team with the input data supplied by 8 Romanian and foreign experts on basis of the Expert-Form elaborated by CITON, makes evident the followings: Cernavoda NPP site is affected by 5 seismic focuses but the seismicity of the site is determined by Vrancea-intermediate source; The seismic acceleration with an annual occurrence frequency of 10-3 events/year is 0.175 g what shows that there is a margin of about 12.5% as to the acceleration considered in the design; To the design acceleration of 0.2 g, an annual occurrence frequency of 6 x10-4 events/year corresponds, providing a more than 'sufficiently small probability' for the seismic loads to be considered in Class C of resistance, according to the seismic qualification practice for CANDU type NPP's. (authors)

  19. The influence of increased temperature of waters from Cernavoda NPP on underground water sources

    International Nuclear Information System (INIS)

    The operation of Cernavoda NPP implies the change of thermal regime of waters in the Danube-Black Sea channel zone. The Danube water is used to cool the NPP systems before being delivered into channel and used in irrigations. The temperature increase of water in Cernavoda NPP installations is between 7 and 12 deg. C. The negative effects of this warming are: 1. limitation of water use for irrigations; 2. occurrence and persistence of fog in channel area; 3. thermal pollution of underground waters and limitation of underground potable water supply. The paper presents a general approach of thermal pollution problems of an aquifer and a mathematical model of forecasting the underground water temperature variation in Danube-Black Sea channel area. (authors)

  20. Knowledge capture and preservation at Cernavoda Unit 2 Project

    International Nuclear Information System (INIS)

    Full text: As it is known, Cernavoda Unit 2 - Romania, is a delayed nuclear power plant (NPP), started in early '80s, works were frozen in 1990 and resumed in 2003 under a management contract concluded by Nuclearelectrica, the Romanian nuclear utility, with Atomic Energy of Canada Ltd (AECL)-Canada and Ansaldo - Italy. This project has many specificities, including long time stored equipment, some works done 15 to 20 years ago; technology developments during these years; only couple of staff available from those initially involved; and a forthcoming project (Cernavoda Units 3 and 4) in its latest development phase. On top of that, like in other Eastern European countries, Nuclearelectrica is losing people due to salary issue and 'brain drain'. In the actual international situation where the nuclear energy contribution to energy mix is under reconsideration and where the demand for qualified personnel significantly exceeds the offer, it is estimated that maybe the biggest challenge of the forthcoming Cernavoda Units 3 and 4 would be availability of human resources. As Cernavoda Unit 2 Project goes towards a successful completion, all those who put lots of efforts and a difficult to overestimate contribution to overcome all challenges of this special Project will leave one after the other. Special attention is being given by Nuclearelectrica and the main contractors AECL and Ansaldo capturing the knowledge (both explicit and tacit) accumulated in these last almost five years and to leave to those who will continue the forthcoming Unit 3 and 4 Projects and to the nuclear industry in general. The objective on knowledge capture and preservation is to gather all experience and lessons learned during contracting, financing, constructing and commissioning of NPP Cernavoda Unit 2, with a focus on tacit knowledge and to asses potential improvements that might be applied in the forthcoming projects, in order to improve nuclear and economic performance. There are couple of

  1. Experience in the application of S.A.T. for maintenance training at Cernavoda N.P.P. - U1

    International Nuclear Information System (INIS)

    A short history of Maintenance Training at Cernavoda NPP Unit 1 will be presented highlighting the fact that: - Cernavoda NPP Unit 1 is the first nuclear power plant in Romania; - Construction/Commissioning and initial operation was done under the direct supervision of expert specialists (from Canada, Italy and US). In addition, the application of Systematic Approach to Training (S.A.T.) principles at Cernavoda NPP for all training activities will be addressed. A short history of how maintenance training activity developed over time will be detailed to address the following issues: - how the S.A.T. stages were applied; - how maintenance experience was gained during Unit 1 Construction/Commissioning initial operation and how this experience has been evaluated, credited and transferred; - how maintenance training was documented; - how the maintenance training activity is organized; - on-the-job training for maintenance personnel. Concerning other training activities at Cernavoda NPP the maintenance begins with a training needs analysis for each maintenance position. These needs are documented through Job Related Training requirements (JRTR's) produced for each maintenance position. During commissioning/initial operation, only necessary maintenance training has been delivered, such as: pump alignments, use of maintenance procedure, application of maintenance documentation. The 'hands-on' activities under expatriates specialists supervision was the main training activity. Training coordinators for each maintenance activity (Mechanical, EI. I-and-C, and Services maintenance) have been appointed to administer maintenance training. Following the declaration of the unit in commercial operation, a new approach has been taken related to maintenance Bucharest A Task Force to evaluate maintenance training status and experience has been established. This group was initiated at the Training Department initiative and it was initially co-ordinated by a Canadian maintenance

  2. How design criteria can improve commissioning/operation/maintenance efficiency for Cernavoda NPP U2

    International Nuclear Information System (INIS)

    The operation and maintenance conditions of a power plant are strongly dependent on its control system. Particularly, the solutions for U2 - BOP/SS (Balance of Plant/Support System) Control System are to be changed, at least because most of control equipment used in Cernavoda NPP U1 are no more available. Although a nuclear unit is not located on a very large area the use of a DCS (Distributed Control System) is attractive; there are information to be changed between MCR (Main Control Room) in the service building, field instruments in TB (Turbine Building), P/H (Pump House), common services in Unit 0, and the 400 kV outstation. The paper deals with the general criteria to be followed for the U2 - BOP/SS Control System design in order to comply with the specific requirements: U2 - MCR must be very similar to U1 - MCR; the use of software oriented control logic has significant impact onto the commissioning/operation/maintenance activities; the simultaneous operation of two units on the site, which are not two independent units nor a plant with two units. After a brief presentation of the supervisory/control functions for BOP/SS systems and of the solution used in U1 the reason to change and the solution for U2 are explained. As conclusion, an inventory of the General Design Criteria for the implementation of the new U2 - BOP/SS Control System is made. (authors)

  3. Intermediate storage and some issues concerning the final storage of spent nuclear fuel at Cernavoda NPP

    International Nuclear Information System (INIS)

    A major objective of 'Nuclearelectrica' National Society (SNN) is to implement nuclear power projects with respect to the sustainable development concept. Examples are given regarding spent fuel and radioactive waste management. Managing the spent fuel according with the concept of sustainable development is demonstrated by the SNN's policy and target objectives of the associated strategy. Spent fuel management strategy is implemented through an optimized staged process. One of the most important stages was completed by commissioning the first unit of the Dry Interim Spent Fuel Storage Facility at Cernavoda NPP site. The dry storage facility is based on the MACSTOR technology , the best proved design of Atomic Energy of Canada Limited and consists of concrete modules, each of them having a 12,000 spent fuel bundles capacity. The designed lifetime of the facility is, at least, 50 years and the present site can accommodate the spent fuel generated by two units during 30 years of operation. Spent fuel storage is the last and the most important stage of disposal. In Romania, by the Government's Ordinance 11/2003 approved by the Law 320/2003 there were assigned the responsibilities within the national waste management system. The newly established National Agency for Radioactive Waste Management will have a fundamental task, being responsible for the end stage of fuel cycle by selecting for the spent fuel disposal an appropriate repository site accepted by the public and a safe and efficient technology with a reasonable acceptable environmental impact. (author)

  4. Cernavoda NPP risk - Based test and maintenance planning - Methodology development

    International Nuclear Information System (INIS)

    The Cernavoda Power Plant starts the commercial operation in November 1996. During operation of the nuclear power plant, several mandatory tests and maintenance are performed on stand-by safety system components to ensure their availability in case of accident. The basic purpose of such activities is the early detection of any failure and degradation, and timely correction of deteriorations. Because of the large number of such activities, emphasis on plant safety and allocation of resources becomes difficult. The probabilistic model and methodology can be effectively used to obtain the risk significance of these activities so that the resources are directed to the most important areas. The proposed Research Contract activity is strongly connected with other safety related areas under development. Since, the Cernavoda Probabilistic Safety Evaluation Level 1 PSA Study (CPSE) was performed and now the study is revised taking into account the as-built information, it is recommended to implement into the model the necessary modeling features to support further PSA application, especially related to Test and Maintenance optimization. Methods need to be developed in order to apply the PSA model including risk information together with other needed information for Test and Maintenance optimization. Also, in parallel with the CPSE study updating, the software interface for the PSA model is under development (Risk Monitor Software class), methods and models needing to be developed for the purpose of using it for qualified monitoring of Test and Maintenance Strategy efficiency. Similar, the Data Collection System need to be appropriate for the purpose of an ongoing implementation of a risk - based Test and Maintenance Strategy. (author). 4 refs, 1 fig

  5. Applying tracer techniques to NPP Cernavoda liquid effluents dispersed in Danube - Black Sea Canal

    International Nuclear Information System (INIS)

    Full text: In this study we propose to use tritiated liquid effluents from CANDU type Cernavoda NPP as a tracer, to study dispersion efficiency on Danube-Black Sea Canal. Tritiated water can be used to simulate the transport and dispersion of solutes in Danube-Black Sea Canal because they have the same physical characteristics as water. A study of experimental published formulas was used to determine proper mixing length. Simultaneous measurements in different locations of the Canal confirm the inlet location of the experiment. Another result used in the further experiment concerns the tritium level along the Danube-Black Sea Canal. We measured tritium activity concentration in water sampled along the Canal between July 2002-April 2003. We established tritium level and tritium concentrations significant for the edge and the tail of tritiated wastewater releases. We obtained unit-peak-attenuation (UPA) curve as related to different mixing times using three locations in which we measured tracer-response curves. During the releases of tritiated liquid effluents we determined the slope of the UPA curve, that helped us to model the water movement in observed area of Danube-Black Sea Canal. In this way with a specific software we can predict maximum concentration of soluble pollutant accidental spills in studied area. (authors)

  6. Occupational exposure in CANDU nuclear power plant: individual dosimetry program at Cernavoda NPP

    International Nuclear Information System (INIS)

    Cernavoda NPP has one CANDU 600 reactor in commercial operation since December 1996. In CANDU type reactors the major contribution (95%) to the external dose is gamma radiation. The major contributor to the internal dose of professionally exposed workers is the tritiated heavy water (DTO), at least 40% of the total effective dose. The main purpose of design and implementation of a 'Monitoring, Evaluation and Recording of Individual Doses Program' (Individual Dosimetry Program) is to measure, assign and record all significant radiation doses (Hp(10), Hp(0.07) and E50) received by an individual during activities performed at the Campus of Cernavoda NPP ensuring at the same time that all the exposure are kept ALARA. Individual dose monitoring is provided by an authorized dosimetric service, licensed by the Romanian regulatory body, National Commission for Nuclear Activities (CNCAN), at Cernavoda NPP. For all the persons entering the radiological controlled areas (NPP employee, short-term atomic radiation workers, contractors and visitors) Health Physics Department provides individual dosimetric surveillance. During fuel loading activities in 1995 individual dosimetric surveillance was provided for 30 individuals using film dosemeters. Since 'Radiation Island' in effect on February 20th, 1996, individual monitoring for external gamma radiation exposure is performed using thermoluminescent dosemeters (TLDs). When entering areas where approved dose rates could be exceeded (variable or heterogeneous gamma radiation fields) beside TLD an electronic, direct reading, Personal Alarm Dosemeter (PAD) is used. When entering working areas with significant neutron dose rates an integrating portable neutron monitor is used (both as field instrument and personal dosemeter). When contact beta-gamma dose rate exceed 10 time the dose rate at the level of the chest, thermoluminescent extremities (hand and/or feet) dosemeters are used. Professionally exposed workers are subject to a

  7. Developing technologies for conditioning the liquid organic radioactive wastes from Cernavoda NPP

    International Nuclear Information System (INIS)

    The Institute for Nuclear Research (INR)-Pitesti has developed technologies for conditioning liquid organic radioactive wastes (oils, miscellaneous solvent and liquid scintillation cocktail) for Cernavoda NPP. This paper describes the new and viable solidification technology to convert liquid organic radioactive wastes into a stable monolithic form, which minimizes the probability to release tritium in the environment during interim storage, transportation and final disposal. These are normally LLW containing only relatively small quantities of beta/gamma emitting radionuclides and variable amounts of tritium with activity below E+08Bq/l. The INR research staff in the radwaste area developed treatment/conditioning techniques and also designed and tested the containers for the final disposal, following the approach in the management of radwaste related to the nuclear fuel cycle. Thus, the INR focused this type of activity on treating and conditioning the wastes generated at Cernavoda Nuclear Power Plant consisting of lubricants from primary fuelling machines and turbine, the miscellaneous solvent from decontamination operation and the liquid scintillation cocktail used in radiochemical analysis. Laboratory studies on cementation of liquid organic radioactive wastes have been undertaken at INR Pitesti. One simple system, similar to a conventional cement solidification unit, can treat radioactive liquid wastes, which are the major components of low- and medium-level radioactive wastes generated by a Nuclear Power Plant. It was proved that the solidified waste could meet the Waste Acceptance Criteria of the disposal site, in this case Baita-Bihor National Repository, as follows: - The wastes are deposited in type A packages; - The maximum expected quantities of this waste stream that will be produced in the future are 50 drums per year. The maximum specific tritium activity per drum is 109 Bq/m3; - Compressive strengths of the samples should be greater than 50 MPa (500

  8. Experience of Cernavoda NPP with siphoning effect on Liquid Zone Control System

    International Nuclear Information System (INIS)

    The spatial neutron flux in Cernavoda NPP's reactor is adjusted by means of light water inventory controlled in 14 zones, using a mechanical system. The system uses 3 water pumps, one in service, one selected stby, one off and a logical associated with water supply header pressure in order to prevent the possibility of inadvertent failure of water supply capability. NPP Cernavoda had experienced loss of running pump on liquid Zone Control System, without automatic starting of the stby pump. Due to spatial reactor core neutron flux system design, as a result of water pressure on supply header decreasing, output air operated valves automatically close to retain all available neutron absorbent light water in the reactor core. Because all 14 zones are connected together to the same pipe drain, the result of fast incoming flow and outgoing flow of water from the zones reduction gives the necessary condition to allow upper zones to drain to the lower ones by siphoning effect. The article describes how this can happen, consequences and safety concerns for this unsafe failure. Also it describes the evolution of neutron flux power during transient in the upper zones of reactor core. (authors)

  9. HTS pH control improvement to reduce feeder wall thinning at Cernavoda NPP U1

    International Nuclear Information System (INIS)

    Since 1996, ultrasonic measurements on outlet feeder pipes indicated that outlet feeder pipes in Heat Transport System of CANDU reactors are corroding at higher than expected rate. The mechanism that causes feeder thinning is Flow Accelerated Corrosion (FAC), a phenomenon known to affect carbon steel components exposed to turbulent flows of deoxygenated water. Experiments suggest that coolant chemistry, particularly pHa, would have a marked effect on FAC rate. Under normal operating conditions, the HTS purification system maintains a stable pHa level of around 10.7. To reduce the rate of FAC, AECL has recommended to CANDU stations to operate towards the pHa range of 10.2-10.4. As a result of the above recommendation, the Cernavoda NPP U1 decided to implement the pHa reduction as soon as possible, using existing systems and equipment. This paper describes the mechanism of FAC and the HTS pHa control improvement to reduce wall thinning using the HTS Purification System at Cernavoda NPP U1. Finally, the advantages of implementing the narrow band pHa control method will be discussed. (authors)

  10. Tritium bearing molecular sieves from NPP Cernavoda - Available options for conditioning prior to disposal

    International Nuclear Information System (INIS)

    In order to recover and reduce heavy water loses and to minimize tritium contamination, drying towers packed with molecular sieve beds are used to retain tritiated heavy water resulting from Cernavoda NPP current operation and leached from various parts of the reactor systems, Molecular sieve during operation are put through cycles of adsorption and regeneration, in fact a desorption phase, and have a lifetime of several hundred adsorption-desorption cycles. After ending their life time the molecular sieves become tritium bearing radioactive wastes and have to be dealt with accordingly. The present paper will briefly describe the current practices for molecular sieve conditioning prior to disposal and the requirements for the conditioned radioactive wastes. Also, the paper presents the development of the conditioning technology for the tritiated molecular sieve capable of realizing a product which matches the waste acceptance requirements imposed by the National Authority for Control of Nuclear Activities, CNCAN, for the disposal at the DNDR Baita - Bihor national repository . (authors)

  11. Technical feasibility of using RU-43 fuel in the CANDU-6 reactors of the Cernavoda NPP

    Energy Technology Data Exchange (ETDEWEB)

    Horhoianu, G.; Patrulescu, I. [Inst. for Nuclear Research, Pitesti (Romania). Physics

    2008-03-15

    Recovered uranium (RU) is a by-product of many light-water reactor (LWR) fuel recycling programs. A fissile content in the RU of 0.9 to 1.0% makes it impossible for reuse in an LWR without re-enrichment, but CANDU reactors have a sufficiently high neutron economy to use RU as fuel. The Institute for Nuclear Research (INR) Pitesti has analyzed the feasibility of using RU fuel with 0.9-1.1 w% {sup 235}U in the CANDU-6 reactors of the Cernavoda Nuclear Power Plant (Cernavoda NPP). Using RU fuel would produce a significant increase in the fuel discharge burnup, from 170 MWh/kgU currently achieves with natural-uranium (NU) fuel to about 355 MWh/kgU. This would lead to reduced fuel-cycle cost and a large reduction in spent-fuel volume per full-power-year of operation. The RU fuel bundle design with recovered uranium fuel, known as RU-43, is being developed by the INR Pitesti and is now at the stage of final design verification. Early work has been concentrated on RU-43 fuel bundle design optimization, safety and reactor physics assessment. The changes in fuel element and fuel bundle design contribute to the many advantages offered by the RU-43 bundle. Verification of the design of the RU-43 fuel bundle is performed in a way that shows that design criteria are met, and is mostly covered by proof tests such as flow and irradiation tests. The most relevant calculations performed on this fuel bundle design version are presented. Also, the stages of an experimental program aiming to verify the operating performance are briefly described in this paper. (orig.)

  12. Ethics of the management of low and intermediate radioactive wastes generated by Cernavoda NPP, a challenge for the Romanian specialists

    International Nuclear Information System (INIS)

    This paper presents the design criteria and the prerequisites for the development of the Radioactive Waste Treatment Plant - RWTP which will comply with L/ILW Final Repository requirements to be built near Cernavoda NPP. The RWTP will be designed to satisfy the main performance objectives in accordance to IAEA recommendation and on basis of the Repository's Waste Acceptance Criteria resulted from the local conditions. One of the most important technological aspect is related to the selection of technologies, which implies, on the one hand, the impact on present generation respectively incineration, radwaste transfer from the SS drums to CS drums, SS drums super compaction and spent filter cartridges cutting, and on the other hand, technologies that isolate for 300 years the tritium and C-14 in the Repository with impact for the next generations. The Saligny Repository will be commissioned in 2014 and in order to accept radwastes from Cernavoda NPP it is necessary that the radwastes are suitably treated for long-term radionuclides isolation. The conditions and requirements including many uncertainties and constraints reduce the possibilities to select the suitable treatment technologies for the Waste Treatment Plant designed for the radwastes generated by Cernavoda NPP, this selection being a critical case due to the limited storage capacity of existing Radioactive Waste Storage Facility. The necessary Radioactive Waste Treatment Plant implies a detailed analysis including ethical aspects of the selected technologies. (author)

  13. Consuming for production - Procurement for power production at Cernavoda NPP - Nuclear Sector

    International Nuclear Information System (INIS)

    The paper presents some aspects relating to the importance of a good communication and cooperation between all factors involved in procurement process at Societatea Nationala 'Nuclearelectrica', SNN. In order to comply with the internal and international rules related to safety in nuclear field and public procurement requirements and for maintaining a high standard of operational performance of Cernavoda NPP, adequate procurement systems were developed by SNN SA. The importance of human factor and the training activities for all personnel from this chain of procurement process is the main key issue to maintain high quality of their activities considering that procurement documents are reviewed and approved before to be issued by all departments involved in procurement process. The specialized department for public acquisition is supervising that the procurement processes initiated at the level of branches, in accordance with their needs and with respect to the requirements of the public acquisition laws and regulations, as well as the specific requirements imposed by the internal Regulatory Body. (authors)

  14. The NPP Cernavoda use to estimate maximum soluble pollutants concentration in Danube Black Sea Channel

    International Nuclear Information System (INIS)

    Tritium, routinely released as low activity liquid radioactive waste by Cernavoda nuclear power plant, was used as a radiotracer to study longitudinal dispersion of Danube Black Sea Channel. A field experiment was carried out in which, after a tritium release, water was sampled downstream from three locations along the channel at periodic intervals. Tritium was measured with a low-background liquid scintillation system and the concentration time evolution for each location was obtained. In order to obtain the channel longitudinal dispersion efficiency, the Unit Peak Attenuation (UPA) curve was plotted. The UPA slope curve was used to construct software that can estimate propagation time of soluble tracer cloud and unit peak attenuation at any location from studied area. (author)

  15. Applying tracer techniques to NPP Cernavoda liquid effluents dispersed in Danube - Black Sea Canal

    International Nuclear Information System (INIS)

    Tritium routinely released as low activity liquid radioactive waste by Cernavoda nuclear power plant was used as a radiotracer to study longitudinal dispersion of Danube Black Sea Canal. A field experiment was carried out in which, after a tritium release, water was sampled downstream from three locations along the canal at periodic intervals. Tritium was measured with a low-background liquid scintillation system and the concentration time evolution for each location was obtained. In order to obtain the canal longitudinal dispersion efficiency, the Unit Peak Attenuation (UPA) curve was plotted. The UPA slope curve was used to construct software that can estimate propagation time of soluble tracer cloud and unit peak attenuation at any location from studied area. (authors)

  16. Economic viability of Cernavoda project

    International Nuclear Information System (INIS)

    Cernavoda project started in 1978, when the CANDU technology procurement contract and other contracts for engineering, technical assistance and procurement were signed with AECL. The works on site started in 1980. In February 1981, a contract was signed with GE - USA and Ansaldo - Italy for balance of plant. After 1989 the concept for project implementation was essentially changed. The completion of Cernavoda NPP Unit-1, established as the first priority by Romanian authorities was implemented by AECL-Ansaldo Consortium (AAC). The objective of the contract signed with AAC consisted in overtaking the management of Cernavoda Unit-1 project, in order to complete, commission and operate the plant for 18 months. The plant was successfully completed, commissioned and commercially operated since December 2, 1996. As concerns Unit-2, only preservation and some remedial works were performed since 1991. In order to support the decision to complete Unit-2, a complete process was initiated: - identification of the activities and associated costs required for plan completion; - plant integration in the utility's least cost development study; - Unit-2 cash flow analysis. A joint RENEL-AECL-ANSALDO team performed a detailed analysis using Cernavoda Unit-1 as reference project and taking advantage of the experience gained during construction, commissioning and operation of the first unit. The least cost power generation development study finalized by SEP and EDF, based on a PHARE funding, ranked Cernavoda Unit-2 on the second place, after two small hydroelectric plants of 53 and 8 Mw e. A cash flow model developed by a RENEL-ANSALDO joint team shows that Cernavoda Unit-2 is an economically feasible project. The financing scenario provides that all resources will be from loans. Other arguments for completion of Cernavoda Unit-2 are: - good performances in operation of Unit-1; - the need to provide jobs for the specialists in the nuclear field; - opportunity for electricity export

  17. Radiation shielding and dose rate evaluation at the interim storage facility for spent fuel from Cernavoda NPP

    International Nuclear Information System (INIS)

    At present studies necessary to license the Interim Storage Facility for the Spent Fuel (CANDU type) from Cernavoda NPP are developed in our country.The spent fuel from Cernavoda NPP is discharged into Spent Fuel Bay in Service Building of the plant, where it remains several years for cooling. After this period, the bundles of spent fuel are to be transferred to the Interim Storage Facility.The dry interim storage solution seems to be the most appropriate variant for Cernavoda NPP.The design of the Spent Fuel Interim Storage Facility must meet the applicable safety requirements in order to ensure radiological protection of the personnel, public and environment during all phases of the facility achievement. In this paper we intend to present the calculation of radiation shielding at the spent fuel interim storage facility for two technical solutions: - Concrete Monolithic Module and Concrete Storage Cask. In order to quantify the fuel composition after irradiation, the isotope generation and depletion code ORIGEN 2.1 has been used, taking into account a cooling time of 7 years and 9 years, respectively, for these two variants. The shielding calculations have been performed using the computer codes QAD-5K and MICROSHIELD-4. The evaluations refer only to gamma radiation because the resulting neutron source (from (α,n) reactions and spontaneous fission) is insignificant as compared to the gamma source. The final results consist in the minimum thickness of the shielding and the corresponding external dose rates, ensuring a design average dose rate based on national and international regulations. (authors)

  18. 'DDSRO' - A specialized software for loop flow computation in shutdown cooling system of Cernavoda NPP

    International Nuclear Information System (INIS)

    Determining pressure, temperature and flow distribution during nuclear reactor shutdown cooling system (SDCS) operation, should provide for an operator a complete image to estimate the efficiency of shutdown cooling process, taking into account installation safety, costs and quality of heat transport system operation during the transient. Only direct operation or process simulation can offer an acceptable image. In case of process simulation, the following ingredients are required: identification of the optimal technological configuration, system parameters connections, each equipment mathematical simulation, connections of equipment models within configuration and numerical simulation based on computational designed codes. The objective of this presentation consists in introduction of 'DDSRO' which represents an individual and independent software designed to calculate the thermohydraulic states of shutdown cooling process in case of Cernavoda NPP, an application that can help to create a complete image required by the nuclear operation. DDSRO characteristics will be presented as follows: DDSRO simulation procedures within mathematical model of each SDCS component and its parameterization (post-shutdown nuclear reactor, heat exchanger water to water, steam generators, shutdown cooling pumps, primary heat transport pumps, headers, feeders, piping, tubing and valves); DDSRO libraries comprising algebraic and differential equations for thermohydraulic transients in numerical form, heavy water and light water properties, matrix and vectors computing (inverse, Jacobi, equation systems solving, etc.), testing and correction coefficients (initial conditions, heat transfer coefficients, equipment temperature coefficients, integration coefficients, etc.) and hydraulic computing (linear and local pressure loss coefficients, hydraulic resistance for each equipment, heavy water and light water flow along each component of system, etc.). Using DDSRO, any reactor cooling state

  19. Safety and engineering aspects concerning L/IL waste repository near Cernavoda NPP

    International Nuclear Information System (INIS)

    The paper presents the main aspects of safety and engineering concerning low or intermediate level of radioactive waste (L/ILW) Final Repository which will be erected near Cernavoda NPP. The L/ILW Final Repository is designed to accomplish the main performance objectives in accordance with IAEA, OECD and US CFR recommendation. At the same time as a basis of this objective it has been taken into account the experience in radwaste management field from Romania and from the developed countries of the shallow land type repository. The Center of Technology and Engineering for Nuclear Project - CITON, as general designer and technical coordinator of the Radwaste Management Program ensures the design of radwaste management, including the chain of activities necessary for enclosure and decommissioning of nuclear facilities. Institute for Nuclear Research - Pitesti is appointed to perform the necessary research, while the Institute for Geophysical and Geotechnics - GEOTEC has been nominated for geological investigation support. The treatment/conditioning of radwastes will be performed according with the best practices in order to assure the long term stability of the containers and radwaste isolation. The disposal structure will be manufactured in accordance with specification of checked procedures and on the provisions of a rigorous AQ/QC program. An important step in order to ensure the proper design of the repository is the correct site characterization which will be performed within the frame of IAEA guidance. The main problems which must be solved in near future are the following: - the elaboration of the Feasibility Study for Repository; - the establishment of a Cooperation Agreement with an experienced organization in order to obtain the necessary tactic and strategic support for finalizing the erection of the repository. (authors)

  20. Contributions to a methodology for periodical verification of the parameters of the control systems at Cernavoda Nuclear plant Unit 1

    International Nuclear Information System (INIS)

    A model identification methodology for periodical verification of the regulating system parameters at Cernavoda NPP Unit 1 was developed. As support to this methodology, the computer program MODELIDENT was implemented in the Java programming language. This program is used for off-line evaluation of the real regulating systems characteristic parameters using an identification algorithm which takes as input data the system response collected for different input excitation signals, a structurally similar model of the analyzed regulating system, and some starting guess value of the unknown parameters. The real values of the parameters are determined during MODELIDENT program execution by applying an iterative algorithm and afterwards are retained as nominal reference values. The success of the identification algorithm is strongly dependent on how appropriately the structure of model's transfer function is chosen. By repeating periodically the identification method, using newly collected data from the process, the current value of the parameters are determined. Any deviations of the new values relative to the nominal reference values are interpreted as de-calibration of the control equipment and in this case corrective maintenance actions have to be taken. With the implementation of the presented methodology at Cernavoda NPP Unit 1 we can make the statement that the preventive maintenance activity is gaining a predictive feature, which can lead to the elimination of major degradation possibilities in the performances of the RS equipment and consequently to increase the NPP availability. On the basis of the experience gained in the practical application of the presented methodology we expect that the identification method will also have beneficial effects in the optimal control of the process systems and also in the activity of Full Scope Simulator software maintenance (the reference values of the identified parameters being used for fine tuning of the simulation models

  1. Probabilistic safety assessment (Cernavoda). Experience and strategies

    International Nuclear Information System (INIS)

    An IAEA project named 'Support for PSA related activities for Cernavoda NPP' was agreed at the beginning of 2000. The objectives were: upgrading of capability and framework to perform deterministic analyses as support for PSA (accident analyses and severe accident analyses); upgrading of capability and framework to extend the scope of PSA model for Cernavoda NPP to include internal and external hazards (internal fire, internal flooding, earthquake); upgrading of capability and framework to perform the Level 2 PSA for Cernavoda NPP. valuation was done for the status of the development of the seismic PSA, fire PSA and flooding PSA. For seismic PSA it was concluded by IAEA experts that this work needs adequate human and financial resources. Decision was taken to coordinate this project from Cernavoda but using specialists from external institutions. A Fire Hazard Assessment-FHA is in progress for Unit 1. First stage, regarding the methodology, was reviewed by IAEA experts in November 1999. In present, work is done for Reactor and Service Buildings. Work on flooding PSA was not started yet. To extend the PSA scope: Capability will be extended to develop the seismic PSA, fire PSA, flooding PSA (procurement of supplementary computer codes and specialist training); the extension of PSA scope to include internal and external hazards will continue after the completion of deterministic studies and is expected that the effective inclusion in the PSA model will start at the end of 2002

  2. New approach of second Romanian NPP siting

    International Nuclear Information System (INIS)

    The NPP sitting studies in Romania began before 1975. The first Romanian NPP CANDU 6 type reactor gone to erection in 1980 on Cernavoda site planned to have 5 units. Gained the experience from Cernavoda NPP sitting, the first mission of new multi-branch of specialists team was to choose new NPP sites adapting the NPP Cernavoda project to the new parameters of close water cooling circuit and hard less and no rock foundation strata. The studies were carrying out in different stages on the inner rivers Olt, Mures, Somes in Transylvania historical region. This paper tries to reconsider shortly the old analysis according to the last IAEA Safety Standards, taking into account the new NPP generation requirement. Paper is focused on geological aspects and other local sites characteristics. (authors)

  3. The licensing process of the design modifications of Cernavoda 2 NPP resulting from the operating experience of CANDU plants

    International Nuclear Information System (INIS)

    The CANDU 6 plant now under construction in Cernavoda include over two hundred significant improvements made in order to comply with current codes and standards and licensing requirements relative to the operating CANDU 6 in Romania. These evolutionary improvements are incorporated in CANDU 6 design taking advance of CANDU operating experience, of the designer company research and development and technical advances worldwide in order to further enhance safety, reliability and economics. This paper gives a general idea of the evaluation of the modifications of the Cernavoda 2 nuclear power plant against the design of Cernavoda 1 and states the safety principles and requirements which are the basis for this evaluation. (author)

  4. A 3D electronic model for unit 2 Cernavoda plant lay-out design

    International Nuclear Information System (INIS)

    Based on the designed and construction experience of Cernavoda Unit 1, in order to provide an integrated approach in performing system, structural and lay-out engineering/construction activities, it is going to be implemented the CAD 3D electronic model of the Turbine Building and associated auxiliary systems. It is suggested a strongly recommended to perform the same approach also for the Reactor/Service Buildings lay-out configuration. This activity is actually developed on the CAD Computer Vision based on a dedicated intelligent date base properly developed for Cernavoda Unit 2 CANDU Nuclear power plant. The main purpose of this integrated approach is hereafter summarized: i. to implement the as built Unit 2 lay-out configuration of the civil structure previously erected and to modify properly the nominal design reference documentation; ii. to optimize properly the plant lay-out anticipating interference check between piping/equipment/cables trays; iii. to produce automatically isometric drawings for the plant construction area by area; iv. to implement automatically the as built lay-out drawings for piping/cables trays saving all the man hours effort required to develop the Unit 1 as built out; v. to provide an automatic input for piping structural qualification just connecting lay-out computer codes (Computer Vision) and Piping Stress Analysis Computer Codes; vi. to provide a complete and detailed design for the plant construction that might be split in portions whose realisation would be transferred to Romanian Contractors on the bases of 'turn-key' contracts. Additionally this effort, even if it might be judged expensive in terms of required man hours effort, should become an important investment, from economical point of view, for the future design and construction activities of Units 3/4/5 in Cernavoda site. (Author)

  5. The examination of the vulnerability of NPP-Cernavoda to a severe accident due to the loss of the entire electrical power supply

    International Nuclear Information System (INIS)

    In this paper it is presented the framework for the PSA Level 2 analysis, where it is selected one of the worst severe accident sequence, such as that initiated from the loss of all electrical power sources SBO (Station Blackout). To examine the vulnerability of NPP-Cernavoda to this severe accident sequence, a complete quantitative analysis is done by using the specialized severe accident code MAAP-WS for NPP CANDU-600. The main result of this analysis is that even if the containment fails, the release of fission products to environment is very low, except the noble gases. An accident recovery can be obtained if we consider the dousing system available initially. Also the course of the accident can be changed if we follow-up the sequences' pathway given in the event trees for containment. (author) 10 figs., 1 tab., 5 refs

  6. The GMF (Group of European Municipalities with Nuclear Facilities) conference at Cernavoda. Opening talk

    International Nuclear Information System (INIS)

    The conference 'Local Competence Building and Public Information in European Nuclear Territories', part of an European Commission project, took place at the Training Center of Cernavoda NPP, on 5-6 April, 2006. Organized by GMF with the support of the town hall and of the Cernavoda NPP, the manifestation gathered over 200 participants, among which representatives of the local public administration in Cernavoda, SN Nuclearelectrica SA, Ministry of Economy and Commerce, Nuclear Agency, CNCAN, ANDRAD, Local Communities and NGOs. The main topics of discussion was the collaboration relationship between local authorities and representatives of the plant regarding public safety and local development. The Mayor of Cernavoda, Gheorghe Hansa and the director of the NPP, Ionel Bucur, stressed that the location of the nuclear plant brings important contributions to the local budget, the socio-economical development of the area, ensuring jobs for most of the town's inhabitants. Speeches were given by Mr Gheorghe Hansa, Ms Blohm-Hieber, the director of the Transport and Energy Division from European Commission, and Mr Ionel Bucur who spoked about the relationship of the plant with the local community. Representatives from France, Slovenia, Sweden, Spain, Hungary and Romania shared their experience about 'The impact on the neighboring areas and the demands from the local authorities'. In his opening talk Mr Chirica Teodor, director general of SN Nuclearelectrica SA, showed that nuclear power in Romania has been based from its very inception on the Western safe technology, as reflected by the excellent safety an economical performances of Cernavoda NPP-Unit 1. Based on the long-term-commitment to nuclear power of the Romanian Government, the commercial operation of Cernavoda NPP Unit 2 is scheduled for the mid of 2007, and will supply 17-18% of the electricity production in Romania. The Romanian Government stressed his strong intention to complete Unit 3 and possibly Unit 4 at

  7. Romania: Cernavoda unit 2. Assessments and evaluations. Annex 9B

    International Nuclear Information System (INIS)

    This annex describes the various assessments and evaluations undertaken to confirm economic and technical viability of unit 2. The extent of modifications and improvements arising out of the suspension period are also identified. (author)

  8. Cernavoda power simulator modernization - A step forward in Romanian low cost maintenance simulation technology

    International Nuclear Information System (INIS)

    At Cernavoda NPP the training is conducted on a Full Scope Simulator, a 1:1 replica of Cernavoda Unit 1 reference plant. For the improvement of training delivery the current task is to define the simulation facilities and structure capable to meet the increased requirements for training, qualification and licensing of nuclear personnel. Besides, this upgrade of simulation facilities should be considered if we are addressing the task of extension of training for Cernavoda Unit 2. In order to achieve this target, if we take into account the deployment of a new simulator, the costs would be extremely high. Many utilities carried out similar strategies, utilizing alternative simulators as a complement to full scope simulator in the areas of training and model maintenance. Therefore, depending upon training requirements and finances, the Cernavoda Unit 1 Simulator modernization providing also an alternative to full scope control room simulator may be a viable option. In this case, the solution that we discuss for Cernavoda training extension is the migration of Cernavoda Unit 1 Simulator to state-of-the-art. The paper has the following contents: - Considerations; - Benefits; - Required tasks; - Simulator Modernization Hardware; - Software Scope; - Executive System Programs; - Development and Debug Programs; - Modeling Software; - Plant System Models; - Graphical Model Builder; - Emulation Software; - Instructor Station Software; - Cernavoda 2 simulation facilities; - Limitations

  9. Considerations related to plant life management for Cernavoda-1

    International Nuclear Information System (INIS)

    Cernavoda-1 NPP, the first CANDU 6 Unit in Eastern Europe, is one of the original five CANDU 6 plants and the first CANDU 6 producing over 700 MWe. CANDU Pressurized Heavy Water Reactors (PHWR) continues to play a significant role in electricity supply both in Canada and some offshore countries (Korea, Argentina, Romania). The commercial versions of CANDU reactors were put into service more than 30 years ago. While the first series of CANDU 6 plants (which entered service in the early 1980's) have now reached the middle portion of their 30 years design life, the Cernavoda-1 was put into service on 2 December 1996. However, the Cernavoda-1 Plant Life Management should be an increasingly important program to Utility ('CNE-Prod') in order to protect the investment and the continued success of plant operation. Over the past three years, INR (Institute for Nuclear Research - Romania) has been working with AECL-Canada on R and D Programs to support a comprehensive and integrated Cernavoda-1 Plant Life Management (PLiM) program that will see the Cernavoda-1 NPP successfully and reliably through to design life and beyond. The PLiM program has a focus on critical systems, structures, and components (CSSCs) and will be applied in three phases: Phase 1 - Planning (assessment and recommendations); Phase 2 - Life attainment implementation, and; Phase 3 - Plant Life Extension (PLEx), also known as plant extended operation. The key activities during each phase are shown. The schedule of each Phase are shown using the in service date of 1983 as the basis. This schedule applies to three original CANDU 6 plants with an in-service date of 1983: Point Lepreau, Gentilly-2, Wolsong-1 and shortly thereafter (1984) the 4th original CANDU 6 Embalse NPP was declared in service. Cernavoda-1 is the 5th original CANDU 6 plant and was put into service on 2 December 1996 (on site activities were started in 1980). The paper will describe the elements of an integrated program, the multiphase

  10. Unit Commissioning of “Belene” NPP (Bulgaria)

    International Nuclear Information System (INIS)

    This presentations gives detailed information about the following topics about commissioning: principles of NPP commissioning; phases of NPP commissioning; organization of commissioning activities; duties and responsibilities of the parties for carrying out unit commissioning activities; responsibility and obligations of the sides during commissioning of power unit; documentation required for power unit commissioning; quality assurance for commissioning activities

  11. The influence of tritium build-up in Cernavoda NPP systems on gaseous and liquid emission after four years of operation

    International Nuclear Information System (INIS)

    Most of the tritium in a CANDU reactor is formed by thermal-neutron-capture reactions, 2H(n,γ)3H, which occurs both in the moderator and heat transport system. Very small amounts of tritiated heavy water may escape from moderator and heat-transport systems of CANDU reactors during maintenance and normal operation. Tritium emissions of Cernavoda NPP were continuously monitored since 1996, when the plant became operational. HTO is continuously sampled on molecular sieves and measured twice a week. Statistical methods were applied to find the emission trend and to develop criteria for identifying abnormal emissions, and to predict the further emissions. During routine operation of a CANDU reactor, various gaseous, liquid, and solid radioactive wastes are generated. The design of its systems ensures that these are minimized but small quantities of gaseous and liquid wastes are continuously discharged at very low concentrations. CANDU reactors are both moderated and cooled by heavy water (D2O). Tritium is produced in CANDU reactors by neutron reactions with deuterium boron and lithium and by ternary fission. Activation of deuterium is by far the most important mechanism which is responsible for the production of about 89 TBq of tritium per MW(e) per year compared to only 0.7 TBq of tritium per MW (e) per year produced by ternary fission. Most of the tritium present in CANDU reactors is in the form of tritiated heavy water - DTO. The sources of tritiated heavy water vapor in reactor building, air are the leaks from the main reactor systems or their auxiliaries. Special dryers were designed and are used to remove moisture from different ventilation systems of a CANDU reactor in order to maintain the gaseous tritium emissions below the limits established by the national authorities. Tritium emissions are monitored both at the stack and in liquid discharges to demonstrate the compliance with the approved Derived Emission Limits. A specialized laboratory using Liquid

  12. Cernavoda project status

    International Nuclear Information System (INIS)

    The Cernavoda project comprises five 633 MWe CANDU units, Unit 1 being the most advanced, with nearly 60% construction completed (at the time of writing). In 1991 the responsibility to complete Unit 1 and bring it into operation was transferred from RENEL (Regia Autonoma Nationala de Electicitate) to a consortium formed by AECL and Ansaldo. Substantial changes have been made in organization, design responsibility, procurement, budgeting, finance, scheduling, training, etc. A continuous quality assurance program has been introduced. Financing includes Canadian and Italian loans. It is hoped that Unit 1 will achieve criticality before the end of 1994

  13. Program of upgrading and safety improvement of NPP V-2 units

    International Nuclear Information System (INIS)

    This paper dealt with the role of Bohunice NPP in the frame of energy production by Slovak Energy joint company, upgrading and safety improvement of NPP V-2 units, basic documents for defining the goals of NPP V-2 units safety upgrading, assessment of safety of NPP V-2 units, program of upgrading and safety improvement of NPP V-2 units, and with the financial resources necessary for upgrading and safety improvement of NPP V-2 units

  14. Preliminary results of a study on hydrodynamics of Danube-Black Sea Channel using tritiated wastewater from NPP Cernavoda

    International Nuclear Information System (INIS)

    In this study we plan to use tritiated liquid effluents from a CANDU type nuclear power plant as a tracer, to study hydrodynamics on Danube-Black Sea Channel, thus extending the observation area along this important man-made channel. This channel is ideal for this kind of study, because wastewater evacuations are occasionally due to technical operations of a nuclear power plant. Tritiated water can be used to simulate the transport and dispersion of solutes in Danube-Black Sea Channel because they have the same physical characteristics as water. Measured tracer-response curves produced from injection of a known quantity of soluble tracer provide an efficient method of obtaining necessary data. This paper presents the mixing length calculation for particular conditions (lateral branch of the channel, and lateral injection of wastewater from nuclear power plant). A study of experimental published formulas was used to determine proper mixing length and the initial location of the experiment. Another result used in the further experiment concerns the tritium level along the Danube-Black Sea Channel. We measured tritium activity concentration in water sampled along the Channel between July-October 2002. The paper also presents future attempts to obtain unit-peak-attenuation (UPA) curve as related to different mixing times. (author)

  15. Cernavoda NPP Unit 1: Operating experience program and plant specific performance indicators (level 2)

    International Nuclear Information System (INIS)

    The basis for the Operating Experience Program was set in place since early stages of the commissioning phase (1993), when a system based on the Canadian approach was implemented for reporting, reviewing, assessing and establishing of the necessary corrective action for unplanned events. This system provided excellent opportunity to train staff in unplanned event assessment methodology, and prepare the station for the formal reporting process following criticality in accordance with the licensing requirements. The formal process, set in place after criticality is described in Station Instruction Procedure SI-01365-P13 'Unplanned Event Report' and was developed under the supervision of Safety and Compliance Department. In parallel, a program for information exchange and trending of performance indicators was developed by Technical Services Department. The WANO recommendations following August 1997 Peer Review provided the opportunity for a better understanding and reconsideration of the Operating Experience Program. As a result, all the activities related to this topic were assigned to a new structure, within Safety and Compliance Department. As such an Operating Experience Group was created and a new program is now being developed in an integrated and centralized manner. The content of the paper is the following: - Overview; - Operating Experience Program; - Event Analysis (Unplanned Events Assessment System - UEIR Process- and Systematic Analysis of Operational Events - ACR Process); - Information Exchange Program; - Monitoring of Operating Experience - Plant Specific Performance Indicators; - Purpose; - Level 2 Performance Indicators. Four appendices are added containing: - A. Station performance indicators/targets (Level 2); - B. SPI (Station Performance Indicators - Level 2) - Graphics; - C. UEIR, LRS (Safety and Licensing Review Sheet), UEFR (Unplanned Event Follow-up Report), ACR and OPEX forms. (authors)

  16. Cernavoda NPP Unit 1: Ensuring heat sink at very low Danube river levels

    International Nuclear Information System (INIS)

    Establishing heat sinks when the level in the Inlet Distribution Basin is continually decreasing must rely as much as possible on the heat sinks provided by the plant design. After the reactor shutdown, the main sources of heat are the decay heat of the fuel from the core and the decay heat of the fuel stored in the Spent Fuel Bay (BCU). These heat sources must be removed through the available heat removal chains. With the RSW available, after the reactor shutdown the Primary Heat Sink will be the Shutdown Cooling System (SDCS) + Recirculating Cooling Water (RCW) + Raw Service Water (RSW) + Class III, with both SDC pumps and both SDC Heat Exchangers (HX). When losing the RSW system, maintaining the HTS pumps in service ensures the fuel is cooled by the forced circulation of the coolant through the Primary Heat Transport System (PHTS), the fuel heat being transferred via boilers to the atmosphere. In addition, to ensure the cooling of the RCW system, alternative cooling sources, like fire water or potable water, are taken into account. (author)

  17. On increasing the utilization factors for NPP and TPP units

    International Nuclear Information System (INIS)

    Factors defining electric power generation at NPP and TPP units operating under base and peak loads are presented. The causes of partial deterioration of equipment reliability and maneuver characteristics of the power units are disclosed. The following conclusions are made on the basis of the results of developments. The increase of power generation at the NPP and TPP units is provided by increasing the technical utilization factor due to the improvement of maintainability and reliability, planning of repairs, resources of the units, components and rate of turn and shutdown of the units, as well as the decrease of the partial failure factor for the equipmant at the power facilities

  18. Report of the IPERS (International Peer Review Service) review mission for the Cernavoda nuclear power plant probabilistic safety evaluation (CPSE -PHASE B) in Romania 3 to 14 July 1995

    International Nuclear Information System (INIS)

    This report presents the results of the IAEA International Peer Review Services review of the internal events Level 1 probabilistic safety assessment (PSA) for the Cernavoda, Unit 1 NPP. The review was based on the PSA documentation available and on intensive communications with the analysis team and representatives from the utility and the plant operator. 7 refs, figs, tabs

  19. Analyses of thermal plume of Cernavoda nuclear power plant by satellite remote sensing data

    Science.gov (United States)

    Zoran, M. A.; Nicolae, D. N.; Talianu, C. L.; Ciobanu, M.; Ciuciu, J. G.

    2005-10-01

    The synergistic use of multi-temporal and multi-spectral remote sensing data offers the possibility of monitoring of environment quality in the vicinity of nuclear power plants (NPP). Advanced digital processing techniques applied to several LANDSAT, MODIS and ASTER data are used to assess the extent and magnitude of radiation and non-radiation effects on the water, near field soil, vegetation and air for NPP Cernavoda , Romania . Cernavoda Unit 1 power plant, using CANDU technology, having 706.5 MW power, is successfully in operation since 1996. Cernavoda Unit 2 which is currently under construction will be operational in 2007. Thermal discharge from nuclear reactor cooling is dissipated as waste heat in Danube-Black -Sea Canal and Danube river. Water temperature distributions captured in thermal IR imagery are correlated with meteorological parameters. Additional information regarding flooding events and earthquake risks is considered . During the winter, the thermal plume is localized to an area within a few km of the power plant, and the temperature difference between the plume and non-plume areas is about 1.5 oC. During the summer and fall, there is a larger thermal plume extending 5-6 km far along Danube Black Sea Canal, and the temperature change is about 1.0 oC. Variation of surface water temperature in the thermal plume is analyzed. The strong seasonal difference in the thermal plume is related to vertical mixing of the water column in winter and to stratification in summer. Hydrodynamic simulation leads to better understanding of the mechanisms by which waste heat from NPP Cernavoda is dissipated in the environment.

  20. Cernavoda Unit 2: - BOP 3D model proposal for a possible organization of site activities

    International Nuclear Information System (INIS)

    The scope of this activity is to define characteristics and advantages of the 3D model of Cernavoda BOP to this set up at site for engineering and construction activities. This model will provide a modern and proven tool able to strongly support the site activities with particular regard to the following: 1. engineering activities, - plant arrangement 'double check' for resolution of clashing; - easy management of future design changes; - real time plant configuration updating as soon as any design modification is approved and integrated in the model; - preparation of high quality documentation for procurement, construction and commissioning; - prompt availability of the as built configuration of the plant as soon as the last modification is frozen; 2. material procurement activities, - definition of the priorities in the construction material procurement according to the construction planning by area; - inventory list of equipment, pipes, fittings, valves, cable trays and ventilation ducts to be installed in each construction area; 3. construction activities, - definition of construction sequences, with particular reference in the congested areas, for piping cable trays (electrical and C-and-I) and ventilations ducts; - definition of piping spools by construction contractors; - follow-up of the activities in each area (i.e. construction, painting, insulation, flushing, pressure testing, etc); 4. turn-over and commissioning, - check of the progress. The success of this approach is based on the following: i) proper management of the remote workstations providing easy and reliable access to the model; ii) subdivision of the Integrated Building in construction areas, whose detail design may be allotted to Romanian organizations with multidisciplinary tasks; iii) integration in the model of the remote developed engineering in order to validate the details of the design. (authors)

  1. Mochovce NPP unit 1 and 2 completion project

    International Nuclear Information System (INIS)

    History of Mochovce NPP is quite long and reflects political changes that happened in Europe in the end of 80'ties. The plant site was chosen in south-west of Slovakia in the frame of Nuclear Industry Development Plan adopted by former Czechoslovak government in 70'ties. In that time was decided to build in Mochovce four VVER 440/213 units together with other NPP's (Dukovany, Temelin, Kecerovce)

  2. Construction prospects of new power units at Khmelnitskij NPP site

    International Nuclear Information System (INIS)

    According to the Energy Strategy of Ukraine for a period up to 2030 it is planned to put into operation power units 3 and 4 of Khmelnitskij NPP by year 2016. In this work considerations are presented on the possible options while selecting reactor unit type for Khmelnitskij NPP power units 3 and 4, which is the main determinant of the cost, construction and commissioning time, and utilization of the existent civil structures. To optimize Khmelnitskij-3 and 4 construction, a survey of the data has been conducted with regard to the possibility of construction of new power units of PWR/VVER type at Khmelnitskij NPP site. The multivariable analysis has been performed based on the projects technical and cost data, construction time and conditions, as well as their compliance with the IAEA and EUR safety requirements for new power units. (author)

  3. Update on Cernavoda

    International Nuclear Information System (INIS)

    The Cernavoda project in Romania is for five 700 MWe CANDU units. Construction began in 1980, but because of problems occurring, many of them associated with political, social, and economic changes in Romania, in 1991 the management of construction of Unit 1 was transferred from RENEL (Regia Nationala de Electricitate) to a consortium formed by AECL and Ansaldo. This had been one of the chief recommendations of a pr-operational safety review conducted by the I.A.E.A. By May 1994, Unit 1 was 93.4% complete, but progress was hampered by the need to rework a number of components, mainly piping. A continuous quality assurance program was in place. Ninety-two Romanian operators were trained by New Brunswick Power at Point Lepreau. As of the date of the conference, the target date for grid connection was March 1995, nine months ahead of the contractual target

  4. Calculational study of NPP turbine unit engine regime

    International Nuclear Information System (INIS)

    Advisability of using engine regime (ER) of NPP turbine units in the case of short shutdowns caused by faulty actuations of protection system, and troubles not calling for generator de-energization, was proved. The method for NPP turbine unit ER realization using reactor after-heat, was developed. It is shown that the developed method efficiency is 25-30% higher as compared with standard ER, and enables one to keep the temperature state of turbine flow section at permissible level during 3 h

  5. Update from Cernavoda

    International Nuclear Information System (INIS)

    On April 16 1995 Cernavoda Unit 1 achieved criticality. This event marked the culmination of roughly 17 years of effort and one of the most troubled histories experienced by any nuclear construction project worldwide. It was also a major milestone in the program begun by AAC (AECL-ANSALDO CONSORTIUM) in 1991 and due to end in June 1997 with the hand-over to RENEL (The Romanian National Electric Utility) of a fully operational CANDU 600 Power Plant. This paper briefly outlines the history of the project, the organisational structure in place and the funding schemes used to ensure its completion. Most attention is given to the present status of the project and those areas and/or issues which have been or continue to be significant problem areas. The future program for the achievement of 100% power and hand-over of the station to RENEL is outlined and potential future problem areas are discussed. (author). 9 appendices

  6. Progress in Decommissioning of Ignalina NPP Unit 1

    International Nuclear Information System (INIS)

    The aim of the paper is to present the Lithuanian legal framework regarding the nuclear safety in Decommissioning and Waste Management, and the progress in the Decommissioning Programme of the unit 1 of Ignalina Nuclear Power Plant (INPP). INPP is the only nuclear plant in Lithuania. It comprises two RBMK-1500 reactors. After Lithuania has restored its independence, responsibility for Ignalina NPP was transferred to the Republic of Lithuania. To ensure the control of the Nuclear Safety in Lithuania, The State Nuclear Power Safety Inspectorate (VATESI) was created on 18 October 1991, by a resolution of the Lithuanian Government. Significant work has been performed over the last decade, aiming at upgrading the safety level of the Ignalina NPP with reference to the International standards. On 5 October 1999 the Seimas (Parliament) adopted the National Energy Strategy: It has been decided that unit 1 of Ignalina NPP will be closed down before 2005, The conditions and precise final date of the decommissioning of Unit 2 will be stated in the updated National Energy strategy in 2004. On 20-21 June 2000, the International Donors' Conference for the Decommissioning of Ignalina NPP took place in Vilnius. More than 200 Millions Euro were pledged of which 165 M funded directly from the European Union's budget, as financial support to the Decommissioning projects. The Decommissioning Program encompasses legal, organizational, financial and technical means including the social and economical impacts in the region of Ignalina. The Program is financed from International Support Fund, State budget, National Decommissioning Fund of Ignalina NPP and other funds. Decommissioning of Ignalina NPP is subject to VATESI license according to the Law on Nuclear Energy. The Government established the licensing procedure in the so-called 'Procedure for licensing of Nuclear Activities'; and the document 'General Requirements for Decommissioning of the Ignalina NPP' has been issued by VATESI. A

  7. Life extension program of KORI Unit 1 NPP in Korea

    International Nuclear Information System (INIS)

    The two phases of Life extension program for KORI Unit 1 NPP are presented. Phase I is completed. It was concluded that life extension is a feasible option in technical and economic aspects. Detailed analysis of RPV is underway, plan for Phase II is finished. It deals with screening and sorting of all relevant SSCs, detailed life evaluation of SSCs, ageing management program and documentation for license renewal application

  8. Analysis simulator for Kozloduy NPP units 5 and 6

    International Nuclear Information System (INIS)

    The analysis simulator for Kozloduy NPP is based on the well known best-estimate code ATHLET and plant analyser tool ATLAS. The model represents all important reactor systems and controllers. It is based on the generic input data deck for WWER-1000/320, which has been constantly developed, verified and validated during approximately 15 years. It has been used for analysing wide spectrum of accidents for different NPP units, including operational events. The first applications of the Analysis simulator for Kozloduy NPP Units 5 and 6 demonstrated its ability for adequate modelling of the thermal hydraulic processes at the plant. Further improvement, verification and validation of the AS are planed. For instance, coupling with the GRS code COCOSYS for a better simulation of the processes in the containment is possible in the near future. The possibilities of the graphical user interface for on-line visualisation and interactive initiation of equipment failures and operators actions make it a very powerful instrument for verification of emergency operating procedures

  9. Development of PSA projects for Mochovce NPP Unit 1

    International Nuclear Information System (INIS)

    For the Mochovce NPP safety measurements project realisation, a list of totally 87 safety measures grouped according their purposes to reach recent international requirements on nuclear safety and reliability was elaborated. In this paper an overview of the Mochovce NPP safety measures is given and it is stressed on the measures related to the PSA (AA-08 - Shutdown and Low Power PSA (SPSA) and AA-10 - Full Power PSA Level 1). The scope of PSA level 1 and SPSA projects developed for Unit 1 are described and the main results are discussed. The Core Damage Frequency (CDF) calculation, contribution of the IEs to the shutdown CDF (total CDF=3.83E-06/year) and to the full power CDF (total CDF=1.66E-04/year) are shown. The developed PSA models can be adopted in the future for the following purposes: living PSA; real time risk monitoring; technical specifications and STIs optimization; level 2 PSA

  10. Fuel assembly leakage, Unit 4, Cycle 22, Paks NPP

    International Nuclear Information System (INIS)

    At the beginning of Cycle 22, Unit 4, Paks NPP the Iodine isotopes activity concentrations raised irregularly in the water of the primary circuit. Analysis supposed that from 1 to 10 fuel rods in one or more newly loaded follower assemblies had lost their integrity. Due to the fact it was not necessary to shut down the reactor, but at the end of the cycle sipping tests were performed for the entire core to find out the facts using a telescope sipping device supplied by H and B Co., Germany. This paper describes the circumstances of the emergence of the problem, the operational inspection and limitation rules in the Paks NPP, the theoretical analysis to estimate the scope and kind of the problem, the sipping device and the measurement/evaluation methods applied for the practical tests, fulfilment the tests, the results and their evaluation and the conclusions regarding the event. (authors)

  11. Full scale dynamic testing of Kozloduy NPP unit 5 structures

    International Nuclear Information System (INIS)

    As described in this report, the Kozloduy NPP western site has been subjected to low level earthquake-like ground shaking - through appropriately devised underground explosions - and the resulting dynamic response of the NPP reactor Unit 5 important structures appropriately measured and digitally recorded. In-situ free-field response was measured concurrently more than 100 m aside the main structures of interest. The collected experimental data provide reference information on the actual dynamic characteristics of the Kozloduy NPPs main structures, as well as give some useful indications on the dynamic soil-structure interaction effects for the case of low level excitation. Performing the present full-scale dynamic structural testing activities took advantage of the experience gained by ISMES during similar tests, lately performed in Italy and abroad (in particular, at the Paks NPP in 1994). The IAEA promoted dynamic testing of the Kozloduy NPP Unit 5 by means of pertinently designed buried explosion-induced ground motions which has provided a large amount of data on the dynamic structural response of its major structures. In the present report, the conducted investigation is described and the acquired digital data presented. A series of preliminary analyses were undertaken for examining in detail the ground excitation levels that were produced by these weak earthquake simulation experiments, as well as for inferring some structural characteristics and behaviour information from the collected data. These analyses ascertained the high quality of the collected digital data. Presumably due to soil-structure dynamic interaction effects, reduced excitation levels were observed at the reactor building foundation raft level with respect to the concurrent free-field ground motions. measured at a 140 m distance from the reactor building centre. Further more detailed and systematic analyses are worthwhile to be performed for extracting more complete information about the

  12. Automatic technological control system of the Kolsk NPP Unit-1

    International Nuclear Information System (INIS)

    Reconstruction of the present centralized control system with application of a new small SM2-9 computer and reactor control system ''Jailyk'' is started at the Kolsk NPP (KNPP). Presented are the flowsheet of the technological process automatic control system (TRACS) of the KNPP first generation after reconstruction, by stage diagram conducting organizational-technical measures on the TP ACS reconstruction and communication flowsheet of the IV-500 MA information subsystem with the SM2-9 computer. The TP ACS reconstruction will make it possible to obtain the unit power up to 115% from the nominal one

  13. Actual status of project Mochovce NPP units 3 and 4 completion

    International Nuclear Information System (INIS)

    In this presentation author deals with actual status of project Mochovce NPP units 3 and 4 completion. Present state of Mochovce NPP, Units 3 and 4 enables real assumption to completion. It is expected that such supplier companies can be used which are experienced in field of nuclear projects. Based on budget of 2002, it seems that completion costs of 45 billions SKK are real. These figures were confirmed by study performed by TRACTEBEL in 2004. Based on experience from Bohunice NPP completion as well as from Mochovce NPP, Units 1 and 2 completion and if decision milestone and project start up deadlines will be observed according to modified preliminary schedule of Mochovce NPP Units 3 and 4 completion, it seems as real that Unit 3 will be completed till 06/2011 and Unit 4 - till 12/2011.

  14. New appraisement of siting for a NPP on Mures river

    International Nuclear Information System (INIS)

    The studies for a second NPP siting on inner Romanian rivers began in a careful manner since 1982 as a first part of the Nuclear Power Plant Romanian Program adopted by political and governmental authorities at the time. The experience gained from Cernavoda NPP siting, the first mission of new multi-branch of specialists team was to choose new NPP sites adapting the CANDU type NPP Cernavoda project to the new parameters of close water cooling circuit and of hard less or no rock foundation strata. The new sites conditions mean a lot of changes of CANDU license and a decrease the output power supplied to the national electric grid. The studies on the Mures river as alternative site of Olt river in Transylvania region began in 1986 and were stopped after 1990. This paper tries to reconsider shortly the old analysis focused on geological and geotechnical aspects and other local sites characteristics according to the last IAEA Safety Standards taking into account also the last types of NPP generations and the number of units. (author)

  15. Operational benchmark for VVER-1000 Kozloduy NPP unit 6

    International Nuclear Information System (INIS)

    Benchmark calculations have been carried out using the 3 D nodal code TRAPEZ. The neutron-physics characteristics of the VVER-1000 core, Kozloduy NPP Unit 6, have been determined taking into account the real loading patterns and operational history of the first three cycles. The code TRLOAD has been used to perform the fuel reloading between any two cycles. The reactor and component descriptions, as well as material compositions, are given. The results presented in the, paper include the critical boric acid concentration, the radial power distribution, the axial power distribution for the maximum overloaded assembly, and the burnup distribution at three different moments during each cycle. Calculated values have been compared with measured data. It is shown that the results obtained by the TRAPEZ code are in good agreement with the experimental data. Thus the information presented could serve as a test case for validation of code packages designed for analyzing the steady-state operation of WWERs. i (authors)

  16. Thermal-hydraulic analyses of the recirculated cooling water from cernavoda n.p.p. unit 1

    International Nuclear Information System (INIS)

    The paper presents the results from a very complex and large analysis performed for the Recirculated Cooling Water System. The analysis was required in order to increase the flow rate for moderator heat exchangers and introduction of a new consumer: urban heating. The system capability to supply with cooling agent all this consumers at all operating regimes from the design manual of the system had to be checked. One concluded that the required modification to the system had no influence in operating the system in all operating condition but there is an issue is regarding the necessity to recalculate the heat load from the moderator heater. The analysis was calibrated by using measurements from the plant, which have been obtained with ultrasonic flowmeters and local indicators. The analysis concludes that the system can change the requirements to the moderator heat exchangers and a new turbine building consumer (urban heating) can be introduced. (authors)

  17. The use of the decision theory and probabilistic analyses in the NPP licensing decision process

    International Nuclear Information System (INIS)

    The licensing process is the place were the use of the decision theory and some specialized analyses, like for instance, the probabilistic analyses is increasing. However this use might be highly misleading if the impact of the actual errors and limitations in the analysis are not considered. The decision theory was actually used in this sense during an actual licensing process of the Cernavoda NPP unit 1 in order to support the decisions taken. (author)

  18. The use of the decision theory and probabilistic analyses in the NPP licensing decision process

    International Nuclear Information System (INIS)

    The licensing process is the place were the use of the decision theory and some specialized analyses, like for instance, the probabilistic analyses, are increasing. However this use might be highly misleading if the impact of the actual errors and limitations in the analysis are not considered. The decision theory was actually used in this sense during an actual licensing process of the Cernavoda NPP unit 1 in order to support the decisions taken. (author)

  19. Systems turnover activities at NPP-Cernavoda

    International Nuclear Information System (INIS)

    The erection of a nuclear power plant requires the utilisation of complex Quality Assurance (QA) programs. These programs implement specific standards, procedures and laws to ensure that the plant is constructed to the highest possible safety level attainable. Some procedures and standards have a narrow field of action while others cover a large area of operation. Such is the case with the turnover procedure presented in this paper, which is one component of the QA program. (Author)

  20. Using large complex units for construction of the Kursk NPP third unit

    International Nuclear Information System (INIS)

    It is shown taking as an example the construction of the third unit of the Kursk RBMK-1000 reactor NPP that enlargement of building structures permits to reduce duration and labour intensity of reactor room construction and to improve work quality. An assembly technology for complex blocks and new method for erection of dispencer collector box are presented. It is concluded that during erection of the most enlarged blocks time period of using main erecting cranes in a main vessel is saved

  1. Seismic upgrading of WWER 440-230 structures, units 1/2, Kozloduy NPP

    International Nuclear Information System (INIS)

    The purpose of this paper is to present final results from a big amount of computational work in connection with the investigations of the possibilities for upgrading of WWER 440-230 structures, units 1/2, Kozloduy NPP. (author)

  2. Readiness of the Mochovce NPP for unit 1 start-up with regards to meeting the requirements for increased safety

    International Nuclear Information System (INIS)

    A safety and reliability of operation of NPP type VVER 440/213, differences between Mochovce NPP and other VVER 440/213 NPPs contributing to the safety improvement, organization of the completion works of Mochovce NPP units 1 and technical condition of the installations are discussed

  3. Operation experience of the advanced fuel assemblies at Unit 1 of Volgodonsk NPP within four fuel cycles

    International Nuclear Information System (INIS)

    The first commissioning of Volgodonsk NPP Unit 1 with standard reactor WWER-1000 (project V-320) was in 2001. The reactor core, starting from the first fuel charge, was arranged completely with Advanced Fuel Assemblies (AFAs). In this way, it is possible to obtain the experience in startup and operation of the core, completely arranged with AFAs, and also to get a possibility of performing the comprehensive check for justification of newly commissioned units and justification of design solutions accepted in the design of reactor core for Taiwan NPP, Bushehr NPP and Kudankulam NPP. The first fuel charge of the Volgodonsk NPP Unit 1 is a reference and unified for Tiawan NPP (V-428), Bushehr NPP (V-446), Kudankulam NPP(V-412) with small differences caused by design features of RP V-320. The first core charge of Unit 1 of Volgodonsk NPP was arranged of 163 AFAs, comprising 61 CPS ARs and 42 BAR bundles. The subsequent fuel charges were arranged of AFAs with gadolinium oxide integrated into fuel instead of BAR. By 2005 the results of operation of the core at Unit 1 of Volgodonsk NPP during four fuel cycles showed that AFA is sufficiently reliable and serviceable. The activity of the primary coolant of the Volgodonsk NPP is at stable low level. During the whole time of the core operation of the Volgodonsk NPP Unit 1 no leaky AFAs were revealed. The modifications of the internals, made during pre-operational work, are reasonable and effective to provide for fuel mechanical stability in the course of operation. The modifications, made in AFA structure during operation of the Volgodonsk NPP Unit 1, are aimed at improving the service and operational reliability of its components. Correctness of the solutions taken is confirmed by AFAs operation experience both at the Volgodonsk NPP, and at other operating Russian NPPs

  4. Rest life time management of Kozloduy NPP units 3 and 4

    International Nuclear Information System (INIS)

    Unit 3 and Unit 4 of NPP Kozloduy are second-generation WWER440/230 energy reactors. Unit 3 was in operation from 1980, Unit 4 - from 1982. No surveillance specimens for monitoring of RPV metal aging are available for both KNPP Units. The reactor pressure vessels rest lifetime assessment, Plant life management and Surveillance program development for the both units are presented and analyzed in this report. (author)

  5. Valves for TPP and NPP in United Kingdom

    International Nuclear Information System (INIS)

    Standard requirements to TPP and NPP valves in the VK are shortly described. Value produser's guarantee, requirements to weld buttering of valve sealing surfaces and to valve quality are described. Devices for valve setting and sealing surfaces grinding, valve control operation, preparation and placing of sealings are described too. Set-ups for hydraulic testing are described

  6. Sitting Safety Aspects of Second Romanian NPP

    International Nuclear Information System (INIS)

    The first Romanian NPP CANDU 6 type reactor gone to erection in 1980 on Cernavoda site planned to have 5 units like the Wolsong applied design project for nuclear island. For the BOP parts the ASALDO-GE project was applied with the careful about the interface connection NSP requirements. The new NPP sitting studies began from 1982 in a serious manner as first part on Nuclear Power Plant Romanian Program adopted by political and governmental authorities at the time. For develop the all package of the studies in concordance with the first IAEA Safety Standards recommendations. Till the 1982 the first mission of design and research multi-branch of specialists team was to adapt the NPP Cernavoda project having a open water cooling circuit to the new parameters of close water cooling circuit. But the team was looking at the other type of NPP for sitting. Also in the same time was studied the possibility of NSP foundation on hard less or soft soil foundation strata in connection with safety aspects. The close circuit of cooling water means others parameters of systems and need very large cooling towers. Also must be reconsidering the safety systems design and performance as new solution. In the south of Transylvania historical region in Romania the Olt River run from west to east having medium multi annual flow around 70 m3/s. The Olt River has a chain of small hydropower in operation and other planned. From geological and geophysical points of view two main faults, along the Olt river valley, one of this having seismically small activities was detected. Site region geotechnical studies show small quantity underground natural gas, salt and peat. The initial nuclear program has imposed 4 NPP units site near Olt River. Taking into account the orogenesis, water cooling needs and other local feature can't be built more than two NPP units on a site. This paper tries to reconsider the old analysis from the last IAEA Safety Standards point of view taking into account the new

  7. Some specific features of building work organization during the Khmelnitskij NPP first unit construction

    International Nuclear Information System (INIS)

    Specific feature of the excavation process during the Khmelnitskij NPP first unit construction, as well as the scheme of mechanization of the main building construction, production of special constructions and their assmbly into mounting units, features of ventilation organizing, preparation, transportation and placement of monolithic concrete are considered. Basic technical-and-economic indices are presented

  8. Verification of Taishan NPP units 1 and 2 design availability factor

    International Nuclear Information System (INIS)

    Appendix 5L 2.1 nuclear island engineering and supply contract (NIEP) of Taishan NPP Units 1 and 2 requires: the average design availability factor is 92%, for a fuel cycle ≥18 months, over a 20 year-period. The performance assessment methodology in EUR Volume 2, Chapter 18 is analyzed and the error in the EUR formula is modified, which is validated by verifying Taishan NPP Units 1 and 2 design availability factor. It can be used as a reference for determining and evaluating the design availability factor performance indicator for a new nuclear power plant design. (author)

  9. Review of state-of-the-art international approaches to seismic design and seismic safety assessment of NPP units

    International Nuclear Information System (INIS)

    The paper describes modern international approaches and requirements on seismic design and seismic safety assessment of nuclear power units, taking into account the lessons learnt from the accident at the Fukushima-1 NPP in Japan. These approaches are to be considered in the revision of current regulations and rules of Ukraine on seismic resistance of NPP units

  10. Analysis of service experience of OPC-417000/750 main unit transformers of NPP units of Ukraine

    International Nuclear Information System (INIS)

    Statistics, design- and technological characteristics of main transformers of NPP units were compiled and analyzed.An algorithm for estimation of the unit transformer state was developed. Reasons of unit transformer failures resulting in forced outage of the units were found.Sensitive zones and probable factors of degradation of electromagnetic, electric insulation and mechanical systems, as well as areas of extreme heat generation were revealed

  11. Ukrainian WWER-type NPP units. Methodological basement, results of cladding tightness inspection

    International Nuclear Information System (INIS)

    In the overview report the generalized results of cladding tightness inspection are reviewed for all Ukrainian WWER-type NPP units. Brief analysis of cladding tightness inspection methodology is drawn. Approaches of Ukrainian NPPs are generalized from the viewpoint of use of widened inspection sample analysis. (author)

  12. Kozloduy NPP units 3 and 4 rest life time program execution

    International Nuclear Information System (INIS)

    In this paper the following tasks are considered: Kozloduy NPP units 3 and 4 life time evaluation; programme for the units life time assuring; units 3 and 4 renewals. The main activities for the programme implementation are described and the obtained results are presented. In conclusion, the executed activities of program for assuring the life time of units 3 and 4 of Kozloduy NPP, cogently prove that the lifetime of structures, systems and components, is assured duly and those structures, systems and components will be in service safely, economically effectively and mostly reliable till the end of the 30 years design lifetime. For some of them it has been proved even for 35 and 40 years. Program activities continue during 2005, although the early shutdown of units 3 and 4 is possible

  13. Reconsidering the site requirements for NPP on Olt River

    International Nuclear Information System (INIS)

    Site studies for CANDU type NPP began in a careful manner since 1982 as a first part of the Nuclear Power Plant Romanian Program adopted by political and governmental authorities at the time. A team was charged to develop all packages of the necessary main studies. The first Romanian NPP CANDU 6 type reactor gone to erection on Cernavoda site, planned to have 5 units and, like Wolsong NPP, applied the same design for the nuclear island. For the BOP parts the ANSALDO-GE project was applied with a thorough concern about requirements raised by connection to NSP. The first mission of design and research multi-branch team was to adapt the NPP Cernavoda project having an open water cooling circuit 'once-through' to the new parameters of a close recirculation water cooling circuit. Also, the structural design was re-evaluated for the case of soft foundation strata instead of hard rock ones. The close recirculation water cooling circuit system was applied for PWR NPP type like in French or other nuclear projects where a rich water source was not available. In case of CANDU type projects cooling water loops were not built so far. The close recirculation circuit of water cooling implies other parameters of the cooled systems and for turbine steam as well, needing very large cooling towers. The initial Romanian nuclear program implied the construction of a 4 units NPP sited near Olt river. This river runs in Transylvania region of Romania from east to west near Boitza village on the northern side of Fagaras Mountains. From geological and geophysical points of view the following main characteristics were found by surveying the Olt River valley: there exist two faults having about east-west direction, one of these having small seismic activities; the stratum for foundation consists of marls or sandy marls; there exist also underground small bags of natural gas or salty strata here and there, as detected by geotechnical borings near the Olt river. The average multiannual water

  14. Seismic soil-structure-equipment interaction analysis of unit 5/6, Kozloduy NPP

    International Nuclear Information System (INIS)

    This research project is aimed to analyse problems of soil-structure-equipment interaction under seismic excitation in case of Kozloduy NPP. Reevaluation and upgrading of Kozloduy NPP has started after 1977 Vrancea earthquake. New Safe Shutdown Earthquake (SSE) level was defined, upgrading most of structural equipment was performed, seismic instrumentation was installed. New investigations were initiated after 1990 IAEA mission visited the site. A comprehensive site confirmation project was started with a subsequent structural and equipment reevaluation and upgrading. This work deals with Units 5 and 6 of WWER-1000 type only

  15. Periodical safety review of units 1 and 2 of PAKS NPP. Examples from summary report

    International Nuclear Information System (INIS)

    On the basis of American practice of qualification and relevant IAEA recommendations detailed guidelines of the qualification procedure were developed and executed on the Units 1 and 2 of the Paks NPP. Periodic safety supervision will be performed by evaluation of the following reports to be submitted by NPP: real technical conditions of the facility; existing practice and proposals for equipment qualification; evaluation of the existing safety reports estimating their validity up to the plant lifetime; ageing and ageing management; procedures of operation, maintenance, supervision; organisation and administration; safety impact of human factor, training, education, qualification of personnel

  16. Units 3 and 4 of Kozloduy NPP - modernized in compliance with the contemporary international standards

    International Nuclear Information System (INIS)

    In this paper the Kozloduy NPP units 1- 4 original design characteristics are given. The main results from units 3 and 4 modernization programme as well as: assurance of reactor core safety; assurance of SLA reliability; assurance of unit safety and reliability are presented. The Kozloduy NPP units 3 and 4 modernization programme and the position of the units in the generally accepted scale of risk assessment are illustrated. The fulfillment of the IAEA and EC requirements and AQG recommendations is also presented. At the end the author concluded that: 1) The results from units 3 and 4 large scale modernization programs realization are assessed by international community as one of the most effective examples of good international practices applying in the filed of the nuclear facilities safety; 2) There are not any technical reasons behind discussions for early closure of units 3 and 4; 3) Taking into account the Balkans electricity consumption prognosis and the condition of the electricity production facilities, Kozloduy NPP units 3 and 4 can have sufficient contribution for the region reliable electricity delivery in the future years

  17. Monitoring system with automatic sampling units around Paks NPP

    International Nuclear Information System (INIS)

    Continuous monitoring of the uncontrolled tritium emission from Paks NPP has been carried out since the starting of the NPP. To control the release of fission and corrosion products automatic samplers were designed and installed into 20 observation wells in the vicinity of the reactor blocks. The automatic samplers contain two columns filled with anion and cation exchange resins and they are equipped with filters for trapping the chelating agents. The samplers are working two meters below the groundwater level. Water pumps fed by accumulator ensure the water sampling through the ion-exchange columns. The conductivity, flow-rate and the volume of the water passed the columns are continuously registered. If the conductivity of the passed water exceeds a prescribed limit (the resins became saturated), the pump is automatically stopped. After a two-month working period the trapped ions are eluted from the resins. The activity of the gamma-emitters, 14C, 90S and transuranic elements are measured in the dried eluate, the tritium activity is measured in the collected water. The automatic samplers have been working for five years at Paks NPP. The experiences are the following: (i) After a volume of 30 - 60 litres of the water passed the columns the resin became saturated. (ii) The efficiency of the chemical digestion was typically 50 - 80 %. (iii) The total gamma activities in the observation wells were less than 1 Bq/L and they were emitted mainly by natural isotopes, first of all 40K. There were no fission products above the detection limit (1E-04 Bq for 137Cs), and we found 1 - 2E-03 Bq/L of corrosion product 60Co only three times in two wells near the main building of blocks 1-2. (iv) The activity concentration of 90Sr was at the detection limit (∼1E-04 Bq/L, Tri-Carb 3170 TR/SL LSC). (v) There was no plutonium or any other transuranic isotopes above of the detection limit of 1E-05 Bq/L. (vi) The activity concentration of 14C was measured on the carbonate content of

  18. Soil unitization in accordance with cesium-137 migration intensity in typical soils of Belarus NPP influence zone

    International Nuclear Information System (INIS)

    In the paper results of soil unitization in accordance with cesium-137 migration intensity in typical soils of Belarus NPP influence zone are presented. It is shown that more than 70% of the Belarusian territory of 30-km NPP zone occupies soils in which mobility Cs 137 is low or moderated. (authors)

  19. Principles on Radiological Characterization of the Unit 1 at Ignalina NPP for Decommissioning Purposes

    International Nuclear Information System (INIS)

    There is only one nuclear power plant in Lithuania - Ignalina NPP (INPP). The INPP operated two similar units with installed capacity of 1500 MW(each). They were commissioned in 12/1983 and 08/1987, and the original design lifetime was projected out to 2010 and 2015 respectively. But the first Unit of Ignalina NPP was shutdown December 31, 2004, and second Unit will be closed down before 2010 taking into consideration substantial long-term financial assistance from the EU, G7 and other states as well as international institutions. Implementation of dismantling activities requires detailed knowledge of the radiological situation at the Unit 1. General Programme of Radiological Survey for Ignalina NPP Unit 1 based on NUREG-1575 was prepared in 2005- 2006 by Consortium led by Lithuanian Energy Institute and approved by Regulatory Bodies. It includes such main steps as historical site assessment, scoping, characterization, remedial actions/decontamination support surveys and final status surveys. General Programme of Radiological Survey defines content and principles of the surveys, and preliminary survey considerations, including identification of the contaminants, establishment of the free release levels, principles on areas classification depending on contamination potential, identification of the final survey units, criteria for selection survey instrumentation, techniques and methods etc. So, in the paper information on these principles and the content of the different stages in General Programme of Radiological Survey is presented. (authors)

  20. Modern practice of cost estimates for the NPP units decommissioning

    International Nuclear Information System (INIS)

    The results of analysis of current practices of cost estimates for decommissioning of nuclear power units with different reactor types present is reviewed. Cost estimates intervals are shown for decommissioning of units with PWR,BWR and AP1000 reactors and the main factors influencing the cost amount are analyzed

  1. Results from modernization of the containment localization systems of the Kozloduy NPP units 3 and 4

    International Nuclear Information System (INIS)

    The improvements of the Accident Localization System (SLA) of units 3 and 4 systematically implemented by Kozloduy NPP shows an important direction for increasing the safety of NPP with WWER-440/V-230 containments. During the years Kozloduy NPP implemented a large scope of activities aimed in full resolution of all generic shortcomings identified in the original design of these containments. These activities allowed already in 2002 to justify that integrity of the containment is assured for all postulated events and the radiological consequences for all DBAs and BDBAs without core degradation are within the regulatory limits. The last phase of this modernization was oriented toward achieving the same goals in case of severe accidents by installation of systems for avoiding long term pressurization of the SG compartments and by installation of a system for keeping of negative pressure (slight vacuum) during the late phases of development of the accidents thus minimizing significantly the uncontrolled radioactive releases from the containment and assured controlled purified release of radioactivity to environment, and for elimination of conditions for H2 deflagration within the localization system. This paper summarizes the results of the whole modernization process with an emphasis of the implementation of the latest phase successfully completed by Kozloduy NPP in first quarter of 2005 which allowed the plant to demonstrate remarkable mitigation capability for a comprehensive set of very low probability severe accidents scenarios in line with the approach now being promoted for the modern design NPPs

  2. Insights from level 1 PSA for Novovoronezh NPP (Unit 5) and PSA-based modifications

    International Nuclear Information System (INIS)

    In the framework of the SWISRUS Project, a level-1 PSA study for Unit 5 of Novovoronezh NPP for internal initiating events has been performed. A number of insights on plant vulnerabilities have been identified. The active participation of plant specialists in the project resulted in a positive plant response, leading to implementation, or planned implementation, of a number of modifications at the plant, based on the PSA results. The effectiveness of the measures taken by the plant, or that are planned to be implemented, are being assessed by the PSA methodology. The plant model is supposed to serve as a basis for a living PSA model for further use by the plant and the regulatory body. The plant senior managers aim to have a living PSA model of the plant as a supporting tool for PSA-based plant safety management and estimation of effectiveness of safety-related improvements to be implemented for Unit 5 of Novovoronezh NPP. (author)

  3. Fast neutron fluences determination for Khmelnitskaya NPP Unit 1 surveillance specimens

    International Nuclear Information System (INIS)

    Fast neutron fluences on surveillance specimens of Khmelnitskaya NPP Unit 1 were determined by results of measurements of neutron-activation indicators accompanied surveillance specimens irradiation. It was shown that reliable transfer of results from surveillance specimens to reactor pressure vessel is impossible and for this purpose, it is necessary to determine space-energy characteristics not only for surveillance specimens locations but for reactor pressure vessel also

  4. Probabilistic soil-structure interactions (SSI) analysis of Kozloduy NPP unit 5/6

    International Nuclear Information System (INIS)

    This work is part of an on-going PSA project on the WWER-1000 units of Kozloduy NPP. Results are presented from the probabilistic response analysis of the reactor building. The probabilistic seismic excitation definition and the probabilistic soil-structure interaction analysis are described. A comprehensive multiple time history analysis procedure is applied. The Latin Hypercube Sampling is used for preparation of the data base for the numerical computation of the reactor building response. (author). 6 refs., 8 figs

  5. Preparation status for continuous operation of Kori unit 1 NPP in Korea

    International Nuclear Information System (INIS)

    Kori unit 1 Nuclear Power Plant is the first commercial operation plant in Korea. In Korea, the life extension of NPP beyond design lifetime reached practically application stage. Preparations status for continuous operation of Kori unit 1, Many researches have demonstrated that life extension beyond design lifetime is possible in terms of technology. This paper is to introduce and to share the continuous operation preparations status and schedule for Kori unit 1 License Renewal Process an additional every 10 years beyond the design life 30 years term. (author)

  6. Level 1 shutdown and low power operation of Mochovce NPP, Unit 1, Slovakia

    International Nuclear Information System (INIS)

    The paper presents general approach, used methods and form of documentation of the results that have been applied within the shutdown and low power PSA (SPSA) study for Mochovce NPP, Unit 1, Slovakia. The SPSA project was realized by VUJE Trnava Inc., Slovakia in 2001-2002 years. The Level 1 SPSA study for Mochovce NPP Unit 1 covers internal events as well as internal (fires, floods and heavy load drop) and external (aircraft crash, extreme meteorological conditions, seismic event and influence of surrounding industry) hazards. Mochovce NPP consists of two operating units equipped with VVER 440/V213 reactors safety upgraded before construction finishing and operation start. 87 safety measures based on VVER 440 operational experience and international mission insights were implemented to enhance its operational and nuclear safety. The SPSA relates to full power PSA (FPSA) as a continuation of the effort to create a harmonized level 1 PSA model for all operational modes of the plant with the goal to use it for further purposes as follows: Real Time Risk Monitor, Maintenance Optimization, Technical Specifications Optimization, Living PSA. (author)

  7. On the switching of NPP power unit transformers from auxiliary network

    International Nuclear Information System (INIS)

    In order to clarify the parameters of direct transformer connection the oscillography of a number of parameters of Zaporozhe NPP network and generators was performed, when switching the 1000 MW power unit transformer complex with 750 kV buses. The complex of transformers consisted of three single-phase 787/24 kV ORts-417000/750-77 type transformers and two auxiliary 24/6.3/6.3 kV of TRDNS-63000/35-72 type tramsformers connected to their 24 kV windings. It is shown that generator excitation forcing conditions arise for several seconds when applying voltage to a power unit step-up transformer through closure of the switch onto NPP high-voltage buses due to high jumps of magnetizing current. A technique of switching power unit transformer through application of voltage from 6 kV auxiliary section with subsequent connection to NPP high-voltage buses via a short-term mode of parallel operation, is mastered

  8. Bases of updating of nuclear safety regulations for NPP in Romania

    International Nuclear Information System (INIS)

    The paper presents the basic principles of reviewing and updating process of the regulatory environment pyramid. The main part of this review process refers to Cernavoda NPP Unit 2. However, there is an important impact on Cernavoda NPP Unit 1. The basic principles were defined in 1993/1994 when the licensing process for Unit 1 was resumed in order to be in accordance with the latest developments of Candu 600 worldwide and with the IAEA and NEA latest recommended documents and practices. After the licensing process for the Unit 1 was completed up to operation stage, CNCAN developed new updated regulations on nuclear safety and the regulatory pyramid in the framework of the RAMG PHARE project. CNCAN issued in 1996 the regulatory Policy for Unit 2, self-sustained and independent of future possible revisions of the regulations. The use of the concept of hierarchical systems, systematic review of safety criteria and objectives and margins along with the feedback from international and national experience on this topic ensured issuance of a reference document for future approach of nuclear safety in Romania. (authors)

  9. Digital I and C upgrade of Kori NPP unit 1

    International Nuclear Information System (INIS)

    The KORI Nuclear Power Plant Unit 1 has upgraded the analog NSSS Control System and NSSS Protection System to the digital based systems. This upgrade was undertaken due to increased maintenance cost required on the existing instrumentation, hardware obsolescence, difficulty in obtaining spare parts, and overall aging of equipment. The scope of work consisted of basic engineering, procurement, detail engineering, licensing support, installation, startup support and total project management. This is the first digital I and C upgrade project in Korea and the plant reached full power operation successfully on September 12 1998

  10. Kozloduy NPP units 1-4 significance for Bulgaria

    International Nuclear Information System (INIS)

    General data about nuclear power in Bulgaria is presented. The main topics covered are: estimated energy reserve; energy balance, new capacities, installed in 2002; information about the WWER-230 reactors operation; environmental impact and global warming; Bulgarian export and regional electricity demand; public opinion etc. The problem 'Long term safe operation vs forced early closure' is discussed. It is concluded that the decision on early closure of any unit should be made on economic grounds or failure to meet regulatory safety standards and must not be politically motivated

  11. European cooperation under the modernization program of the Kozloduy NPP units 5 and 6 and its evolution during the Belene NPP construction

    International Nuclear Information System (INIS)

    The major part of the modernization program for the Kozloduy NPP units 5 and 6 is being performed by the European Consortium Kozloduy (ECK), consisting of AREVA - FRAMATOME ANP (Germany and France) and Atomenergoexport (Russia). The ECK main project, consisting of 76 separate measures, shall be finished in the first half of 2006. One of the major tasks was to form the different teams on contractors and employers side such that the works can be executed effectively in a timely manner and as per the technical and quality requirements. Different actions were undertaken on both sides in order to assure the main target, namely to implement the complete scope of work within the contractual time schedule. So far it can be reported that the teams have successfully worked and as a matter of fact at present more than 100 outage days have been saved compared to the initial contractual time schedule. This important result is based on different success factors in the field of planning, engineering and design, outage organization, implementation including testing and commissioning, quality assurance. After the decision of Bulgaria to continue the erection of Belene NPP, a bidding consortium has been founded by the ECK Consortium members, in order to provide a joint offer for this project. The good reputation, expertise and the experience gained from the Kozloduy NPP units 5 and 6 modernization project together with a reliable network with Bulgarian industrial partners may contribute the utmost to a successful finalization of the Belene NPP. (author)

  12. Power up rate plan of NPP PAKS units

    International Nuclear Information System (INIS)

    PAKS investigates the way to up rate the power of units to the 108% of the original nominal level. This thermal power level makes possible to reach the 500 MW (gross) electric power production. Present paper shows the main features of new nominal state. To help the evaluation of power up rate from fuel side, a 2-step fuel modernization procedure is planned. In the 1st step a slightly modified fuel with increased pin pitch and Hf layer in followers planned to be introduced, in the 2nd step geometrically modified fuel with higher enrichment and burnable poison. The article also contains the description of the planned transient and equilibrium cycles. During the transient cycles the nominal power and the fuel also will change (Authors)

  13. The experience of service life prolongation of NPP units of the first generation

    International Nuclear Information System (INIS)

    Full text: During the last 6 years in Russia there were executed works with regard to a substantiation of the service life prolongation for NPPs of the first generation with WWER-440, RBMK-1000, EGP-6 power units, which have 30 years service lifetime initially prescribed by the design. For the purpose of NPPs lifetime prolongation there was developed an approach which enables to estimate the actual state of NPP components at the end of the design service life. The approach is based on the analysis of the operation history, design-experimental assessment of metal condition in zones with maximum damaging, determination of ageing mechanisms in such zones, selection of optimal methods and devices for non-destructive testing, carrying out the on-site inspection and providing verification calculation of components' strength using all collected data. In accordance with the obtained results a conclusion about technical condition and residual lifetime is being performed. By substantiation of lifetime management the NPP main equipment were analyzed from the point of view of the base mechanisms of operational ageing of materials. Also it the frame of service life prolongation work there were used special new devices intended for carrying out the assessment of NPP equipments' metal condition, including devices for mechanical properties measurement, inspection of metal flow-accelerated corrosion wear, measurement of metal magnetic properties. In the report there are presented the results of comprehensive researches of the pipelines' and equipments' metal condition, as well as modern inspection procedures are performed. Also there are reviewed data of original experimental researches of thermal-deformational ageing of full-scale test-samples used for prediction of the metal mechanical properties to the end of extra service life period till 45 years of unit operation. Also the methodology of on-site inspection of metal irradiation embrittlement of the reactor power vessels is

  14. Preparation phase of Mochovce NPP unit 3 and 4 construction completion

    International Nuclear Information System (INIS)

    In this presentation authors deal with preparation phase of Mochovce NPP unit 3 and 4 construction completion. The preparation phase of the Mochovce unit 3 and 4 construction completion gives following main outputs: (a) Detail Safety Concept gives definitive complex safety and technical improvement of MO34, more precise analysis of the total cost of construction completion, a list of potential suppliers and construction completion time schedule; (b) Appendices of Basic Design Documentation and Preliminary SAR serves as basic documentation for UJD SR decision making according to Law No. 541 for start of Realization Phase; (c) The Preparation Phase represents effective tool for start of MO34 construction completion Realization Phase.

  15. Strat-up testing in the engine room of the Khmelnitskij NPP first power unit

    International Nuclear Information System (INIS)

    Specific features of thermal-mounting works at the Khmelnitskij NPP first power unit and main stages of start-up testing which befgan in April, 1987, are considered. Main specific feature of works is the so-called pure mounting of the feedwater pipeline system with the following passivation of internal surfaces with an inhibitor. It permitted essentially to decrease afterinstallation corrosion of pipelines. Thus, a set of start-up tesing carried out provided with indices of water-chemical conditions corresponding to the standards of operation in two works after power unit start-up

  16. Safety enhancement of Kozloduy NPP units 5 and 6 using PSA-1 and other studies

    International Nuclear Information System (INIS)

    The paper describes briefly the background, objectives and organisation of the Kozloduy NPP 'Upgrading Programme for Units 5 and 6' developed in 1994. The classical probabilistic safety analysis (level 1) of these units have been used as criteria for evaluation of the changes already made. This PSA-1 study is the first of the kind for WWER-1000 reactors. It is based on a methodology of IAEA and includes internal and external initiators of accidents. Results from seismic probabilistic risk assessments are also reported. (author)

  17. Monitoring system with automatic sampling units in the surroundings Paks NPP

    Science.gov (United States)

    Svingor, É.; Molnár, M.; Palcsu, L.; Veres, M.; Pintér, T.; Köves, L.

    2006-01-01

    Continuous monitoring of the uncontrolled tritium emission from Paks Nuclear Power Plant (NPP) has been carried out since starting the NPP operation. In order to control the release of fission and corrosion products as well as 14C automatic samplers were designed and installed into 20 observation wells in the vicinity of the reactor units. The automatic samplers contain two columns filled with anion and cation exchanger resins and are equipped with filters for trapping the chelating agents. The samplers are placed two meters below the groundwater level. Water pumps fed by accumulator ensure the water flowing through the ion-exchange columns. After a two-month working period the trapped ions are eluted from the resins. The activity of the gamma-emitters, 14C, 90Sr and transuranium elements are measured in the dried elute, the tritium is measured in the collected water phase. The experiences of a five-year monitoring work in the surroundings of Paks NPP are given here.

  18. Continuous operation of NPP Kori Unit 1 - Fireproof paint for cables

    International Nuclear Information System (INIS)

    Fireproof cable coating materials have been used in European NPP, especially in Germany, Russia, Ukraine, Czech Republic, Lithuania, Switzerland. Wide experiences were made during operation while applying these systems. In NPP Kori, Unit 1, a fire proof cable coating project was realised for the first time in a NPP of KHNP. The scope of services of the cable trays to coat amounts to 15,587m2. In different fire compartments and rooms the cables should be coated partially respectively completely with the fire proof cable coating system. The extent of cable surfaces to coat was stipulated by KHNP on the basis of an analysis made by KHNP. The project was tendered on the basis of a technical specification of KHNP. The specification is mainly predicted on Korean and US standards. The most important criteria for the fire proof cable coating is resumed as follows: The fireproof cable coating has to assure the fire protection of the cables for a period defined and for operational conditions defined in such a manner that the general conditions for the operation of the cable installation will not be affected

  19. Environmental Radioactivity Levels within New EPZ from Shin-Kori NPP Unit 3 and 4

    International Nuclear Information System (INIS)

    The EPZ (Emergency Planning Zone) boundary is one of priority matters to protect against the release of radioactive materials in the accident of NPP(Nuclear Power Plants) efficiently and quickly to minimize environmental impacts. In U.S. with regard to the size of EPZ, Section 50 and 47 of 10 CFR part 50 require that an EPZ consist of an area approximately 16 km in radius for the plume exposure pathway and 80 km in radius for the ingestion pathway from the NPP, respectively. In Korea, it is required that EPZ should consist of an area approximately 8 to 10 km in radius depending on the site characteristics, without any difference between the plume exposure and ingestion pathways. The environmental radiation level in Ulsan was predicted for new EPZ from Shin-Kori NPP Unit 3 and 4. The outdoor gamma doses and natural or artificial radioactivity concentration in some samples measured was shown to be within the background range of the Korea. Accordingly, it was thought that the nuclear power plant has not significantly affected the background radiation level

  20. Environmental Radioactivity Levels within New EPZ from Shin-Kori NPP Unit 3 and 4

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Dong Han; Kim, Hee Reyoung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2015-05-15

    The EPZ (Emergency Planning Zone) boundary is one of priority matters to protect against the release of radioactive materials in the accident of NPP(Nuclear Power Plants) efficiently and quickly to minimize environmental impacts. In U.S. with regard to the size of EPZ, Section 50 and 47 of 10 CFR part 50 require that an EPZ consist of an area approximately 16 km in radius for the plume exposure pathway and 80 km in radius for the ingestion pathway from the NPP, respectively. In Korea, it is required that EPZ should consist of an area approximately 8 to 10 km in radius depending on the site characteristics, without any difference between the plume exposure and ingestion pathways. The environmental radiation level in Ulsan was predicted for new EPZ from Shin-Kori NPP Unit 3 and 4. The outdoor gamma doses and natural or artificial radioactivity concentration in some samples measured was shown to be within the background range of the Korea. Accordingly, it was thought that the nuclear power plant has not significantly affected the background radiation level.

  1. Report of the ASSET (Assessment of Safety Significant Events Team) mission to the Cernavoda nuclear power plant in Romania 8-12 August 1994 Division of Nuclear Safety. Root cause analysis of a significant event that occurred during commissioning of unit 1

    International Nuclear Information System (INIS)

    The IAEA Assessment of Safety Significant Events Team (ASSET) report presents the results of the team's investigation of a significant event that occurred during commissioning of Unit 1 of Cernavoda nuclear power plant. The results, conclusions and suggestions presented herein reflect the views of the ASSET experts. They are provided for consideration by the responsible authorities in Romania. The ASSET team's views presented in this report are based on visits to the plant, on review of documentation made available by the operating organization and on discussions with utility personnel. The report is intended to enhance operational safety at Cernavoda by proposing improvements to the policy for the prevention of incidents at the plant. The report includes, as a usual practice, the official response of the Regulatory Body and Operating Organization to the ASSET recommendations. Figs

  2. Test simulation on studying xenon-poisoning oscillations at Kalinin NPP, unit 3

    International Nuclear Information System (INIS)

    The report deals with the results of simulating the experimental studies of the reactor plant behaviour and the core characteristics in the xenon transients caused by a small and large decrease in the reactor power and also a small increase thereof. The experimental studies were performed in the end of burn-up (Teff ∼ 244 eff. days) of the first fuel loading at Kalinin NPP, Unit 3. A comparative analysis of the testing data and the results of neutron- physical calculations was made with the use of code package SAPFIR95 and RC. (authors)

  3. Compex system for teaching and training operators for TPP and NPP power units

    International Nuclear Information System (INIS)

    Requirements, taken as a principle for constructing the system for operator teaching and training (OTT), have been formulated on the basis of investigation of operators' work at TPP and NPP power units. Functional structure and a structural block-diagram for OTT are built. As a criterion, which determines the structure of any trainers, being a part of OTT a requirement has been chosen satisfying the correspondence beetween habits developed with the help of trainers and habits of real operators' work. Results of analysis permit to confirm that refusal or under statement of the role of any stage of operator training leads to reduction of quality of his training

  4. Results from probabilistic safety analysis level 2 for Kozloduy NPP units 3 and 4

    International Nuclear Information System (INIS)

    The study considers full power operation analysis results and impact of strategies and modernisation implementations of Kozloduy NPP units 3 and 4. In this paper the following issues are discussed: the development of Severe Accident Management Guidelines and Symptom Based Emergency Operating Procedures, installation of brand new system as Emergency Filter Ventilation System, Passive Autocatalytic Hydrogen recombiners, etc. In order to respond to the objectives of the study, the analyses assets the impact of different initiating events on risk based on the frequencies of various plant damage states, the confinement failure and the radiological release frequencies and finally estimates the total risk as frequency of radiological releases

  5. Seismic response analysis and upgrading design of pump houses of Kozloduy NPP units 5 and 6

    International Nuclear Information System (INIS)

    The main objective of the presented project was to perform a feasibility study for seismic/structural evaluation of the safety related structures at Kozloduy NPP Units 5 and 6 for the new site seismicity and determine if they satisfy current international safety standards. The evaluation of the Pump House 3 (PH3) building is addressed in this paper, which was carried out by applying appropriate modeling techniques combined with failure mode and seismic margin analyses. The scope of the work defined was to present the required enhancement of the seismic capacity of the Pump House structures.(author)

  6. Nuclear safety assessment for Cernavoda NPP Unit 1 in the case of large break loss of coolant/loss of class IV power supply

    International Nuclear Information System (INIS)

    This nuclear safety analysis is performed in order to provide the results of pressure and temperature transient in containment, fission product release and dose analysis, carried out for an 80% ROH (Reactor Outlet Header) break with a total loss of Class IV electric power supply at the time of reactor trip. Containment is modelled using a four-node (room) and six-link (opening) representation of the reactor building using the PRESCON2 code. Noble gases are treated as inert species. Iodine species are modelled as liquid aerosols that are produced from the breakup of the jet from the break discharge. The analysis assumes an instantaneous self-preserving 0.1 percent conversion to organic iodine species. Aerosols are modelled by using twenty-six particle size classes in the 0.1 μ to 10,000 μ range. (author)

  7. Redesign of emergency water supply system by-pass line from Cernavoda NPP Unit 1 and 2 using self regulating valves

    International Nuclear Information System (INIS)

    In this paper one considered improving the EWS (emergency water supply system) by-pass line in order to replace current manual operated valve with an self operated valve. This change is necessary in order to reduce the human error events in operation of the system in case of a DBE (design basis earthquake). The paper describes a theoretical and practical operation of a system using self regulating flow rate valves. Basically, the elimination of a possible human error in operating a system is important for nuclear safety in case of a DBE because it makes it avoidable in normal reactor cooling systems. The paper describes checking of the functioning of this equipment in operating conditions, investigating how it responds to various operating regimes. (authors)

  8. An assessment of the fire protection requirements throughout a NPP life related to current IAEA regulations and American, Canadian and UE regulations

    International Nuclear Information System (INIS)

    Statistics on fires has surprisingly shown that the frequency of fires in a nuclear power plant are as high as in the conventional industrial units. The analyses on fires occurred in a NPP need to consider both their well-known severe damages and the nuclear consequences. In 1975 a severe fire occurred in BROWNS FERRY NPP due to the ignition of the polyurethane foam used in the electric cable penetration sealings. The fire propagated to the cable channels and damaged over 1600 cables. The fire event revealed important shortcomings in the fire protection design and procedures. The fire represented a crucial event that changed fundamentally the fire protection regulation in the United States nuclear industry. The fire protection programs, standards and guides currently applied, have been developed on basis of this fire analysis and gained conclusions/experience. The purpose of the article is to be a short presentation of the fire protection requirements for all NPP life stages (i.e. design, construction, commissioning, operation and decommissioning), including the most recent issues of the standards, codes, guides and regulations in US, Canada, IAEA and some European countries. Such documentation represented the main technical support in establishing the national fire protection standard design regarding all the stages of a CANDU-6 NPP life, all the types of operational NPPs, particularly for Cernavoda NPP Unit 1 and Unit 2 (now in an advanced stage of construction). In order to satisfy the requirements provided by this documentation, as practically as possible, a list of analyses and fire protection improvement measures for Cernavoda NPP is presented. (authors)

  9. External hazards in the PRA of Olkiluoto 1 and 2 NPP units - Accidental oil spills

    International Nuclear Information System (INIS)

    Oil transports in Finnish territorial waters have increased significantly during the last 10 years. The Gulf of Finland is at this moment a very important route of oil being transported from Russia to the Western Europe. Although the number of accidental oil spills is decreasing in amount and in size, there is a growing concern of their effects to nuclear power plants (NPPs). The amounts of oil transported on the Gulf of Bothnia are much smaller than on the Gulf of Finland. However, accidental oil spills have occurred also there, the size and amount of which are smaller, though. Accidental oil spills are often a result of grounding of a ship or collision of two ships, and often occur during harsh weather conditions like storm or dense fog. However, also coastal oil depots may break, the oil of which may spread over wide distances on the sea. The modelling of initiating events resulting from accidental oil spills includes oil spill response actions performed by the regional rescue services, alarming of the oil spill by the emergency response centre to the NPP rescue services and spill response by the NPPs rescue services. It is unclear what the consequences are if drifted oil would enter the coolant water tunnels. The effect of different oil types to the operation of the safety-related service water systems and components are being assessed. In the ultimate case, an oil spill would clog the inlet channels thus failing the ultimate heat sink of the NPP units. The licensee is evaluating what is the optimal way to operate the NPP units in the case that an oil slick is threatening the plant to ensure reactor core cooling and RHR. The continued operation of, and especially the cooling of, at least one auxiliary feedwater pump is critical in the mitigation of the initiating event. Strategies, like reversing the water flow of the cooling water channels or closing of the cooling water channels, are being evaluated. (authors)

  10. Level 1 PSA study of Mochovce unit 1 NPP (SM AA 10 and 08)

    International Nuclear Information System (INIS)

    This paper presents genesis of Level 1 PSA project preparation for all operational modes of Mochovce NPP unit 1 including the description of its' main objectives, scope and working method. The PSA study which includes full power (FPSA) as well as shutdown and low power conditions (SPSA) Level 1 PSA has to support the nuclear safety improvements of the unit. They evaluate the basic design and the benefits of all improvements, which were found necessary to be incorporated before the start-up of the unit. The study includes internal events (transients and under-loss of coolant accident, LOCAs), internal hazards as fires and floods and selected external hazards as earthquake, influence of external industry, extreme meteorological conditions and aircraft crash.The PSA (both FPSA and SPSA) models is developed using the RISK SPECTRUM PSA code. (author)

  11. Phenomena investigations and SAMG development for Kozloduy NPP units 3 and 4

    International Nuclear Information System (INIS)

    In this paper the Kozloduy NPP units 3 and 4 Severe Accident (SA) vulnerabilities; performed analyses and results are presented. The results, from investigation of units 3 and 4 behavior in Severe Accident (SA) conditions, show that the installation of H2 recombination system and leakage control and venting systems ensure effective management of the highly importable SAs. These systems ensure containment integrity and reduce radiological consequences by orders of magnitude. The Severe Accident Management Guidelines (SAMG) structure; SAMG strategies and entry criteria as well as EOPs interface are also considered. The SAMG has been developed in accordance with IAEA requirements and using EdF approach and has been harmonized with existing EOPs for operation facilitation. At the end it is concluded that SAMG development after upgrading of the localization systems puts the Kozloduy units 3 and 4 in the small group of NPPs that are able to manage and withstand SAs

  12. Study of environmental impact assessment for Mochovce NPP Units 3 and 4. Executive summary. September 2007

    International Nuclear Information System (INIS)

    SE/ENEL, on a voluntary basis, has prepared new EIA Study for the completion of Units 3 and 4 of Mochovce Nuclear Power Plant (MO34 NPP) according to International current practices and European Directives. The results of the analysis, according to SE/ENEL Environment and Corporate Social Responsibility policies, will be provided to local Communities and Public Authorities. The Environmental Impact Assessment is performed: - in compliance with appendix 11 of Slovak Act. No. 24/2006 'On the assessment of the effects on the environment and on the modification and enlargement of some laws'; - meeting the requirements of the Exhibit II 'Illustrative list of potential social and environmental issues to be addressed in the Social and Environmental Assessment documentation' as reported in the document 'Equator Principles' of 2006 July developed by the International Finance Corporation (IFC). The area of Mochovce NPP is situated in Central Europe in the south-western region of the Slovak Republic (SR) at the western border of the Levice district. The area lies in the south-western part of the Kozmalovske hills mainly in the Hron highlands. From the point of view of the terrestrial and administrative organization of the SR, Mochovce NPP is situated in the eastern part of the Nitra region, in the north-western part of the Levice district, close to the border with the Nitra and Zlate Moravce districts. Mochovce NPP is approx. 12 km from the district capital Levice, which is the largest town within a 20 km distance from the power plant. Initial site preparation began in August 1983. In April 1998 the first fuel was loaded into Unit 1 of Mochovce NPP. The operation started in August 1998. Unit 2 started operation in January 2000. The original Construction Permit No. Vyst. 2010/86 for MO 34 was issued by the District National Committee in Levice on the basis of the Land Planning Decisions on 12 November 1986. This Permit has been renewed firstly on 5 May 1997 by letter of the

  13. Rotor elements of combined turbo-pump units for automated emergency feedwater system of NPP heat and mass exchange equipment

    International Nuclear Information System (INIS)

    The paper offers promising alternative advanced options for drives of feeding devices based on combined turbine units, considering the use of wet steam as a working medium. It explains the dependence of the efficient start of turbo-pump units on the degree of information support of NPP process control system

  14. Problem-oriented system of design of technology of equipment dismantling at NPP units decommissioning

    International Nuclear Information System (INIS)

    The principles for construction of the problem-oriented system for designing the NPP equipment dismantling technology during power unit decommissioning are considered. The rules of the design space organization and use basing on application of the information and expert methods taking into account the action of the factors characterizing the technology functioning medium effects are applied as initial elements for the system construction. The general scheme for building the models used when developing the equipment dismantling technology is described in details. It is shown that the technological principles of conducting the works connected with the equipment dismantling are mostly determined by the work volumes. The basic variant of NPP power unit decommissioning under modern conditions in Russia involves safe monitored storage with final reactor dismantling after long time period (for 30-100 years) in order to provide its components activity decreasing due to natural radioactive nuclide decays. At that the main condition for dismantling technology functioning is following the radiation safety requirements for personnel, population and environment

  15. Evaluation of environmental tritium level in the area of Cernavoda Nuclear Power Plant

    International Nuclear Information System (INIS)

    This work is a continuation of the study entitled Evaluation of environmental tritium levels before and after start of a new tritium source for model verification' that commenced two years ago as part of an European research contract having as objective the 'Investigations and Modelling of the Dynamics of Environmental HT/HTO/OBT Levels Resulting from the Tritium Releases'. The aim of this study was to evaluate the environmental tritium level in pre-operational stage of Cernavoda Nuclear Power Plant and the dynamics of variation of tritium concentration in the first operational years of NPP, for determination of site-specific transfer parameters and model validation. Representative samples for Cernavoda area were analyzed; - air humidity; - water from Danube River, Danube-Black Sea Canal and lakes; - drinking, rain and snow water; - HTO concentration in soils at different depths; - tissue free water tritium in vegetal and animal foodstuffs relevant for human diets like cereals (wheat, maize, barley). vegetables (potatoes, tomato, cabbage, onion, bean), grapes and wine. The mean concentration of tritium obtained in 1996 for these types of measurements is presented. The values of tritium concentration in air, water, soil and plants are as low as for areas without contaminating sources. The operation in 1996 of the Cernavoda NPP did not modify the tritium environmental level. (authors)

  16. Rupture of DN 500 - design basic accident at units 3 and 4 of Kozloduy NPP

    International Nuclear Information System (INIS)

    The original design of Kozloduy NPP Units 3 and 4 assumes as Design Basis Accident (DBA) the rupture of DN 32 mm primary pipeline, while an initial event of double-sided guillotine break of primary pipeline with maximal diameter is not considered. In the course of units modernization it have been demonstrated once and again that both the emergency core cooling systems and the localization systems can cope with larger and larger primary circuit leaks. After the installation of a Jet-Vortex Condenser (JVC) at Units 3 and 4 it was substantiated that, the integrity of the hermetic rooms is ensured even in case of double-sided guillotine break of a primary circuit pipeline with maximal diameter (DEGB). The technical justification of the jet-vortex condenser, elaborated by VNIAEC, contains calculations determining both the source term and the doses obtained outside the NPP site after LOCA DN 500. LOCA DN 500 is considered in these analyses as a beyond design basis accident and it is so included in the SAR and approved by the Nuclear Regulatory Agency (NRA). The thermo-hydraulic calculations performed later on show that the emergency core cooling systems can cope with this initial event at conservative assumptions. In order to classify this initiating event as a design basis accident it is necessary to demonstrate that the core cooling criteria are fulfilled and the internal and external doses outside the NPP site are within the permissible limits fixed for design basis accident by the Bulgarian regulatory body (NRA), when using conservative assumptions. For this purpose two consecutive studies were performed - evaluation of the DEGB probability and categorization of the initial event according to the contemporary regulations acting in Republic of Bulgaria. The presented report summarizes the results of the performed conservative analyses of double-sided guillotine break accident of main circulation line taking into account the probability of rupture of large diameter

  17. Systematic evaluation of the Cernavoda nuclear power plant physical protection system

    International Nuclear Information System (INIS)

    Full text: For three years at Cernavoda NPP is working a process to systematic evaluating the effectiveness of the Physical Protection System (PPS). Due to the fact that this evaluation has to be continuous, the first important step is to define a baseline to compare periodically the performance of PPS against it. The necessity of that process has been identified as follows: the continuous changes in the field of perceived threats against Cernavoda NPP and the necessary measures to respond to that changing climate; the needful to improve the performance of PPS against certain threats in conjunction with the needful to allocate substantially financial and human resources to cover the discovered weakness in the system; an assistant to take the appropriate measure in case of indisponibility of one or more components or parts of the PPS. The second step is the continuous tracking of the behavior of PPS in order to determine: the maintenance resource allocation and the priorities of the work; the predictive behavior of installed components to determine the future appropriate measures, including budget dimensioning. SAVI is a PC compatible program developed by SANDIA Laboratory (USA) for comprehensive analysis of PPS effectiveness. That program is organized in two modules: the Adversary Sequence Diagram (ASD) module and the outsider module modeling trough specific codes both the characteristics of PPS and of the predicted adversary. Combining the two modules related to a specific PPS and adversary is possible to find out the effectiveness of the physical protection system for each vital zone along to ten possible paths to penetrate by adversary, starting with the most vulnerable one. Because of two conservative assumption considered by the SAVI algorithm (adversary know the PPS characteristics and they use an optimal penetration strategy), the measure of effectiveness (probability of interruption - PI) is very realistic and conservative related to the necessary

  18. Radiation safety control on Ulchin NPP Unit 1 s/g sleeving

    International Nuclear Information System (INIS)

    Ulchin NPP unit 1 has been entered its tenth operation year. As the operation years went by, S/G tubes' defects have been reported, which was analyzed mainly due to PWSCC through ECT and various studies. In the ninth overhaul, technical staffs of Ulchin unit 1 decided to do sleeve installation for defected tubes. This sleeve installation was a second experience on our plant in KEPCO. The sleeving tubes were estimated to 600 pieces, but increased to 987 pieces by ECT results. As the sleeve installation was performed in high radiation level, we have considered various radiation safety, i e. protection of radiation source and internal exposure. The collective radiation exposure dose was recorded to 142.32 man-mSv and no internal exposed person was discovered. But there are some requirements to improve radiation safety for reducing exposure dose to radiation. PWSCC : Primary Water Side Stress Corrosion Crack (author)

  19. Project Management Unit for decommissioning of NPP Bohunice VI (2003-2014)

    International Nuclear Information System (INIS)

    From October 2003 until december 2014 the Consortium consisting of Iberdrola Engineering and Construction (leader). Empresarios Agrupados Internacional, and Indra Sistemas has carried out the project Project Management Unit ((PMU) for the decommissioning of Bohunice V1 NPP (units 1 and 2), type VVER-440/V-230 in Slovakia. during the first phase (2003-2007) EdF was also part of the Consortium. The project is funded by the Bohunice International Decommissioning Support Fund (BIDSF) administered by the RBRD. The main objective of the project is to provide the necessary engineering and resources of project management for planning, execution, management, coordination and monitoring of all tasks in support of the decommissioning. (Author)

  20. Sensitivity Evaluation on the ROH Quality for the DBA Safety Analysis of Wolsong NPP Unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Hyun; Choi, Seong-Soo; Han, Sang-Koo [IT Venture Town, Daejeon (Korea, Republic of); Kim, Sung-Min; Kho, Dong-Wook [KHNP-CRI, Daejeon (Korea, Republic of)

    2015-05-15

    As one design characteristic of the CANDU-6 NPP (PHWR Type), boiling of the primary coolant is allowed a little bit. The initial condition for the safety analysis of 2.82% was adopted as a LCO (Limiting Condition for Operation) in the ITS (Improved Technical Specifications) of Wolsong NPP Unit no.1. For this sensitivity study on the ROH Quality, three representative events - LBLOCA, SBLOCA and Loss of Flow (LOCL4) - were selected and the effects of quality on the thermal hydraulic behaviors of coolant system and trip coverage effectiveness of shutdown systems ( SDS1/2) were evaluated. The effects of various ROH qualities from 2.82% up to 4.12% on the safety analysis results of LBLOCA, SBLOCA and LOCL4 were evaluated. The initial conditions of various ROH qualities do not give rise to noticeable effects with respect of thermal hydraulics of coolant system and containment for the LBLOCA event. SBLOCA and LOCL4 got a little effect from various ROH qualities - larger increase rate in the reactor power and coolant pressure due to larger qualities. However, the effects are not significant to have an effect on the integrities of fuel and coolant system boundary. The various ROH qualities up to Design Limit of 4.0% would not bring significant safety effects for the three DBAs in the Trip Coverage viewpoint.

  1. Informing the Lithuanian public about the decommissioning of Unit 1 at Ignalina NPP

    International Nuclear Information System (INIS)

    The final decision about decommissioning of Unit 1 at Ignalina NPP by 2005 was taken when the Lithuanian Parliament approved the National Energy Strategy in 1999. In 2000 the Board of the European Bank of Research and Development (EBRD) approved the establishment of the Ignalina International Decommissioning Support Fund and the International Donors' Conference took place in Vilnius. Sweden's longterm co-operation with Lithuania in the area of nuclear safety started already in 1992, soon after the country had regained its independence. SIP (Swedish International Project Nuclear Safety) administers this bilateral assistance. Public information has been included in the Swedish programme since the establishment of the Information Centre at INPP and is also a part of the bilateral decommissioning support. SIP finances a series of TV-programmes on a national channel and the local cable TV in Visaginas (the town close to Ignalina NPP) about various aspects of decommissioning. The Lithuanian regulatory authority VATESI uses its experience in public relations to inform about the situation related with decommissioning. The authority organizes 'Open Doors' days and press conferences to provide objective and trustworthy information. The reaction of the viewers to the TV-programmes were very positive and Sweden will continue the support to the information programme in Lithuania. (author)

  2. Sensitivity Evaluation on the ROH Quality for the DBA Safety Analysis of Wolsong NPP Unit 1

    International Nuclear Information System (INIS)

    As one design characteristic of the CANDU-6 NPP (PHWR Type), boiling of the primary coolant is allowed a little bit. The initial condition for the safety analysis of 2.82% was adopted as a LCO (Limiting Condition for Operation) in the ITS (Improved Technical Specifications) of Wolsong NPP Unit no.1. For this sensitivity study on the ROH Quality, three representative events - LBLOCA, SBLOCA and Loss of Flow (LOCL4) - were selected and the effects of quality on the thermal hydraulic behaviors of coolant system and trip coverage effectiveness of shutdown systems ( SDS1/2) were evaluated. The effects of various ROH qualities from 2.82% up to 4.12% on the safety analysis results of LBLOCA, SBLOCA and LOCL4 were evaluated. The initial conditions of various ROH qualities do not give rise to noticeable effects with respect of thermal hydraulics of coolant system and containment for the LBLOCA event. SBLOCA and LOCL4 got a little effect from various ROH qualities - larger increase rate in the reactor power and coolant pressure due to larger qualities. However, the effects are not significant to have an effect on the integrities of fuel and coolant system boundary. The various ROH qualities up to Design Limit of 4.0% would not bring significant safety effects for the three DBAs in the Trip Coverage viewpoint

  3. Classification of the systems and equipment of Kozloduy NPP Units 5 and 6

    International Nuclear Information System (INIS)

    Background: For modernization of the Units 5 and 6 of the Kozloduy NPP it was proposed to classify the systems and equipment according to safety, seismicity and quality. The new classification can be used for implementation of new equipment, exchange of existing equipment and for maintenance and in-service inspection procedures. Objectives: The objectives of the presentation are to provide information on the establishment and implementation of a new system of safety, seismic and quality classification of Units 5 and 6 systems and components. Results: The safety classification of the systems and components is performed according to the actual Russian Basic Safety Regulation OPB 88/97. This Regulation is used as a basic document and the IAEA Safety Guide No. 50-SG-D1 is used for confirmation of systems and components safety functions, and in order to reflect the international basis. The quality classification of the equipment and pipelines is performed according to actual Russian standard PN AE G-7-008-89 'Rules on Design and Safe Operation of Components and Pipelines of Nuclear Power Installations' - the basic standard for Kozloduy NPP units 5 and 6. The seismic categorization of the equipment and buildings is performed according to IAEA Safety Guide No. 50-SG-D15 and considering the Russian seismic design standard PN AE G-5-006-87. Conclusions: The new classification system fulfills up-to-date international requirements, is based on new regulations in the country of the plant origin and takes into account international safety guides and norms. (authors)

  4. Rest lifetime evaluation and ageing management in NPP 'Kozloduy' unit 1-4

    International Nuclear Information System (INIS)

    In 1992 as a result of an IAEA SRM review the 'WANO 6-month program' has been issued to improve operation, maintenance nad safety culture for the four WWER 440/230 units at the NPP 'Kozloduy' Siemens has awarded 3 contracts related to RTL evaluation of the main equipment, integrity of reactor pressure vessel and to the leak-before-break behaviour of the main piping od unit 2. It is pursuit an overall strategy that allows to: implement on the basis of RTL evaluation a long term ageing management program (AMAP) for Kozloduy's units 1-4 to assure their operation until the end of their design life; identify those components and equipment for which from the safety point of view urgent and immediate actions have to be performed; increase step by step the safety and reliability according to the Western standards and to internationally accepted safety culture; keep open the possibility of life extension as far as this would be technically feasible and acceptable and economically reasonable. Under the technical leadership of Siemens studies have been performed related to the subject of integrity and RTL, such as: reirradiation of RPV samples from Unit 1 and 2; evaluation of PV embrittlement of Unit 1; transfer of the results of LBB assessment of Unit 2 to Units 1, 3 and 4; transfer of results of RTL evaluation of Unit 2 to Units 1, 3 and 4; PTS analysis of RPV of Unit 1, 2,3 and 4. The main remarkable results are: no life-limiting mechanisms detected, requiring immediate actions, except for RPVs; residual lifetime determined for RPVs on reliable basis of advanced modern PTS analysis and sample testing; necessary activities in monitoring of ageing and in-service inspection clearly identified successful proof of lBB for main primary piping after slight modification of supports; international experts agreement reached (e.g. Risk Audit, successful IAEA experts meetings and OSART missions)

  5. NPP operation, 2001

    International Nuclear Information System (INIS)

    Results of NPP service in 2001 on a global scale are presented. Numerical data on service indexes of NPP in different countries are reviewed. Summary power of operating NPP in 2001 was as much as 372 857 MW. List of ten NPP having the best characteristics in electric power generation on one nuclear bock is given. Nuclear power plants of Germany were recognized as the best units on a global scale

  6. Interactive model of the steam generator blowdown system of the Kozloduy NPP units 5 and 6

    International Nuclear Information System (INIS)

    A program complex for full scale modelling of the WWER reactor dynamics 'RADUGA-EU' has been developed. The complex includes: program complex 'RADUGA - 7.3' - for non-stationary neutron-hydraulic calculations of reactors with 3-dimensional reactor core; package TPP (Thermal Power Plant) - for modeling of non-stationary and stationary processes in complicated thermal-hydraulic networks (including primary and secondary circuit of NPPs and TPPs); program 'GENERATOR' - for modeling of the electric generator; program 'MVTU (Modeling in technical devices)' - for modeling, analysis and optimisation of dynamical processes. The 'RADUGA-EhU' is used for calculations of thermal-hydraulic processes in the steam generator blowdown system of the Kozloduy NPP units 5 and 6. An interactive model of the blowdown system has been created. It is used not only for testing of technical solutions, but also as interactive environment for the development of the equipment operational regulations

  7. Chemical mode in secondary circuit of the Dukovany NPP units after TG condensers replacement

    International Nuclear Information System (INIS)

    The increase of the pH of SG feedwater on the 1. unit of Dukovany NPP led to enhancement of chemical mode of secondary circuit, what was identified in particular by the following: Reduction of concentration of iron in SG feedwater, Reduction of concentration of Sodium and Sulfates in SG blowdown water. This reduction is caused by shutdown of CPS thus by elimination of release of Na ions and SO4 from wrong operated ion-exchangers and their subsequent regeneration (part of cation exchanger in Na form and part of anion exchanger in SO4 form). Reduction of the WANO SG chemical index to the minimum theoretical value. It will be necessary to change criteria characterizing this index or to introduce our own modified index. In relation to CPS shutdown the costs for operating chemicals and for demineralized flushing water were reduced. (authors)

  8. Reliability research based experience with systems and events at the Kozloduy NPP units 1-4

    International Nuclear Information System (INIS)

    An overview of equipment reliability based on operational data of selected safety systems at the Kozloduy NPP is presented. Conclusions are drawn on reliability of the service water system, feed water system, emergency power supply - category 2, emergency high pressure ejection system and spray system. For the units 1-4 all recorded accident protocols in the period 1974-1993 have been processed and the main initiators identified. A list with 39 most frequent initiators of accidents/incidents is compiled. The human-caused errors account for 27% of all events. The reliability characteristics and frequencies have been calculated for all initiating events. It is concluded that there have not been any accidents with consequences for fuel integrity or radioactive release. 14 refs

  9. Preserving the life extension option for Wolsong NPP Unit 1 through plant life management program

    International Nuclear Information System (INIS)

    The first CANDU 6 plants, including Wolsong Unit 1 nuclear power plant (NPP) (which entered service in the early 1980's) are now approaching two thirds of their thirty-year design life. Korea Electric Power Research Institute (KEPRI) and Atomic Energy of Canada Limited (AECL) have worked together since 2000 to develop and implement a comprehensive and integrated CANDU Plant Lifetime Management (PLiM) program for Wolsong Unit 1 NPP. PLiM will see this plant successfully and reliably through to the design life and preserve the option for life extension. The focus of the initial phase of the program is on the major critical components and structures and any potential aging phenomena that might affect plant safety and availability. In-depth life assessments of Wolsong Unit 1 critical systems, structures, and components (CSSCs) are under going. It is recognized that effective plant practices in inspection, monitoring, maintenance, and operations are the primary means of managing aging through the design life and necessary for preserving the life extension option. Hence, the PLiM assessments identify enhancements to current plant programs to mitigate aging effects and to ensure reliable life attainment and performance. The KEPRI/AECL co-operation for the PLiM program over the last few years is providing in-depth assessments and promising life prognosis for the key CSSCs of Wolsong Unit 1. The assessments are also identifying those areas for optimized plant inspection, monitoring and maintenance programs to achieve utility targets for safety, reliability and production capacity during extended life. These outcomes are important inputs to decision makings to embark upon a detailed Wolsong Unit 1 life management program. In this paper, the PLiM program assessment methods and techniques tailored to the components, like CANDU 6 steam generators, are described. A typical proactive aging management program for steam generators, aimed to continue current excellent service for

  10. Testing manoeuvrability of WWER-1000 at 5 unit of Zaporozhe NPP

    International Nuclear Information System (INIS)

    Specific features of the WWER-1000 reactor control algorithms under maneuverable conditions during everyday load management are discussed. The results of the suggested algorithm verification at the Zaporozhe NPP fifth unit are presented. It is shown that unlike to power management under normal operation conditions involving reactor transition from one stationary state into another, in a case of the reactor power daily variations it constantly operates under transients because of the xenon oscillations. The feasibility of WWER-1000 power unit operation under daily load management schedule at the core lifetime end is proved. The reliable and high-efficient algorithm assuring control of the reactor power level and power density distribution under minor water exchange which is not higher than that under normal operation is developed. Different variants of manual and automatic reactor regulating rod groups control, as well as operating modes for reactor power and turbine regulators are tested. The conclusion is made that the calculational prediction obtained using the IR program is completely confirmed in the course of tests. The control algorithm suggested assures power daily variations at a power unit with the WWER-1000 reactor with load decreasing lower 50 % of the rated power level

  11. Safe decommissioning of units 1 and 2 of Kozloduy NPP: selection of safe enclosure time period

    International Nuclear Information System (INIS)

    The time period foreseen for Safe Enclosure is internationally varying from 30 years to 100 years. A SE period of about 70 years was considered for Kozloduy NPP, prior to start the development of 'Technical Design for the Decommissioning of Kozloduy Units 1 and 2' and detailed assessment of all factors which have influence on the SE duration. This paper shows that, on the basis of the analysis performed in the project, for safety, technological and economical reasons it is possible to reduce Kozloduy NPP SE time to 35 years. The following factors have been analysed: The radioactive decay: the surface and mass contamination acceptance criteria enabling to achieve the European Community requirements for free release level remain practically constant for a SE period .35 years. There is thus no benefit in term of decontamination factor reduction, to extend the SE period beyond 35 years. Similarly 35 years after the reactor final shut down, the . dose rate of the primary circuit will drop below 3 μSv/h and will become then negligible. From the health physics and decommissioning standpoints, there is no benefit in extending the SE period beyond 35 years. Costs and investments: After the reactor final shutdown and during the SE, some systems and equipment will remain in operation to ensure the safe conditions of the nuclear buildings: ventilation, radiation monitoring, fire protection etc. The costs associated to the maintenance and repair and in some cases to the replacement of these equipment as well as the surveillance costs will be reduced. Similarly, the costs associated to the maintenance and repair of the civil engineering structures, including their structural integrity and confining capabilities will also be reduced. The duration of SE time is also bounded to the possibilities to raise the needed funds for the decommissioning

  12. Verification of a SAPPHIRE living PSA-Model for Leningrad NPP Unit 1

    International Nuclear Information System (INIS)

    With the help of the SAPHIRE Risk Monitor software, the Kurchatov Institute developed a pilot (preliminary) Living PSA-Model (LPSA-Model) of Leningrad NPP Unit 1. The model includes electronic version of a Database (about 10000 Basic Events), electronic versions of Fault Trees and Event Trees and linkage of Event Trees. The model consists of 11 Initiating Events and 10 Safety Systems. For this reason the model is a preliminary (pilot) model. For verification of the model it was necessary to carry out a number of calculations for additional Initiating Events. The additional Initiating Events are fires in various compartments of the NPP. Each fire is considered as an Initiating Event with certain frequency. Each fire removes from service so-called active equipment: pumps, electrical and manual valves, electrical drives and so on. The calculations were carried out for plenty of possible fires. During the calculations of each fire, structure of the LPSA-model was not changed, but Fault Trees for the appropriate systems, which are removed from service during the fire, were changed. Also the frequency of the Initiating Event, relating to disconnection of the system, which gives water to separator drums, was changed. Removal of the components from service was carried out with the help of changing of boundary conditions in the Fault Trees. The validation computations resulted in that the LPSA-model is applicable for various Initiating Events and various Safety Systems. Calculation of one variant requires approximately 2-3 minutes of PC Pentium 4 running time, i.e. the model runs in real time regime. Thus the validation computations have shown, that there is opportunity to monitor quickly (only without visualization) operational safety levels of Russian NPPs with the help of SAPHIRE LPSA- models. Such PSA-models are completely adapted to inclusion them into the Idaho (SAPHIRE) Risk Monitor. (authors)

  13. Subcriticality assurance of fuel containing materials at the destroyed ChNPP Unit 4 regulatory requirements

    International Nuclear Information System (INIS)

    Agglomerations of fuel containing materials (FCM - alloys, core fragments etc.) are located inside the Sarcophagus (Shelter)of the ChNPP unit 4, which was destroyed by a beyond-design basis accident. Based on conservative assessments, these materials contain about 200 tons of nuclear materials (NM). These agglomerations are currently in a sub-critical configuration, but the Shelter does not provide conditions as would be required by regulations for safe storing of high-level waste (HLW) and NM. Though the risk of criticality is minimal, application of regulatory requirements would provide additional assurance of safety. Requirements to assure sub-criticality while storing NM are established in the regulatory documents of Ukraine for ordinary storage facilities. These have been used in general for the Shelter, but certain specifics need to be considered such as the un-organized location of NM agglomerations, the complexity of their access, potential collapse of concrete structures, and openings in the Shelter confining shell. To reduce effectively the criticality hazard ChNPP should avoid water intrusion into FCM agglomerations beyond the amount for which criticality is possible, provide measures to prevent structural collapse in premises with FCM as well as substantial changes in FCM physical and chemical composition, provide reliable monitoring of nuclear safety (NS) parameters in premises with FCM, provide measures for active control of FCM subcriticality, in particular, introduction of neutron absorbing material. This report covers the usage of regulatory requirements to minimise the potential for criticality within FCM agglomerations inside the existing Sarcophagus and, in future, inside the New Safe Confinement (NSC), the construction of which is planned according to the International Shelter Implementation Plan (SIP). (author)

  14. New products formed due to interaction of fuel and construction materials in the 4th unit of Chernobyl NPP

    International Nuclear Information System (INIS)

    Characteristics of damages in the 4th unit of Chernobyl NPP are given. Regions of localization of released fuel are indicated and its modifications are characterized. Correlation of location and routes of sample selection for one of typical products of fuel interaction with structural materials of the unit - 'elephant's foot' - are presented. Results of physochemical an radiochemical analyses are produced. Certain assumptions are made as to possible scenario of accident in the south-east guadrant of the reactor vault

  15. Cernavoda NPP - A competitive energy source for sustainable development

    International Nuclear Information System (INIS)

    At present a trend manifests world wide toward promoting nuclear power, for increasing its performances, toward maintaining competitiveness and sustaining the programs of development and application of advanced nuclear technologies. These objectives will be achieved by improving: operation performances; management of life-cycle, quality management; technical infrastructure; human resource performances; international cooperation for developing innovative nuclear technologies; technologies and applications of advanced reactors. Fostering the Romanian nuclear power on the basis of CANDU 6 type rectors, the developing in Romania of an advanced industrial infrastructure, the economical, environmental and social aspects and their interplay with nuclear power development are the main subjects presented in this work

  16. Digital control computer upgrade at the Cernavoda NPP simulator

    International Nuclear Information System (INIS)

    The Plant Process Computer equips some Nuclear Power Plants, like CANDU-600, with Centralized Control performed by an assembly of two computers known as Digital Control Computers (DCC) and working in parallel for safely driving of the plan at steady state and during normal maneuvers but also during abnormal transients when the plant is automatically steered to a safe state. The Centralized Control means both hardware and software with obligatory presence in the frame of the Full Scope Simulator and subject to changing its configuration with specific requirements during the plant and simulator life and covered by this subsection

  17. Managing delayed projects. Cernavoda NPP - Romania. Importance of NGO involvement

    International Nuclear Information System (INIS)

    In Romania there is a diversity of civil societies with respect to the attitude towards nuclear power. Among the dedicated societies supporting nuclear power development there are: the Romanian Atomic Forum (Ratomet), affiliated to the European Atomic Forum; the Romanian Nuclear Power Association (Arden), affiliated to the European Nuclear Society; the Romanian Radioprotection Society (SR Rp), affiliated to the Radiation Protection Association. The main dedicated activities of above mentioned Non-governmental Organizations (Ng) are: establishing contacts and organizing meeting with Romanian political decision making factors, mass media representatives, institutional entities, civil society ect.; orienting and co-coordinating activities of Romanian companies involved in production and services for nuclear energy; serving as contact point for relevant international communication and business relation; creating internal working groups for certain theme or sub-domain and suggested solution for a particular issue, including experts even from outside of the association; performing lobby activities ect

  18. Cernavoda NPP - Boiler and steam cycle chemistry control

    International Nuclear Information System (INIS)

    Steam generators protection against corrosion and fouling is an ongoing issue for nuclear power plants. The true effectiveness of the secondary chemistry control program is best judged by the absence of secondary side corrosion related tube degradation particularly that leads to tube plugging or sleeving or tube support degradation. To continue striving for excellence in chemical control, the following issues should be considered: Continuous evaluation of the effectiveness of the chemistry control program in mitigating SG damage; Evaluation of plant compliance with the program; Laboratory quality assurance program to assure that laboratory analyses are accurate and reproductibile; Quality assurance program for on-line monitoring equipment to assure that results from this equipment are accurate. (R.P.)

  19. Report of the IPERS (International Peer Review Service) pre-review mission for the Cernavoda nuclear power plant probabilistic safety evaluation (CPSE - PHASE B) in Romania 31 October to 3 November 1994

    International Nuclear Information System (INIS)

    This report presents the results of the IAEA international peer review services pre-review mission which reviewed the status of the present version of the Cernavoda probabilistic safety evaluation, a Level 1 internal events Probabilistic Safety Assessment for the Cernavoda, Unit 1, nuclear power plant. 2 refs

  20. Foreign Material Exclusion Program at CNE Cernavoda Nuclear Generating Station

    International Nuclear Information System (INIS)

    In the face of a continuing attention to operations and maintenance costs at nuclear power plants, the future of the industry depends largely upon increasing plant availability and improving operating efficiency. The success in achieving these objectives is dependent upon the success of each plant's equipment maintenance program. Preventing the introduction of foreign materials into a nuclear power plant system or component requires a careful, thoughtful, and professional approach by all site personnel. This paper describes a proactive approach to prevent the introduction of foreign material into systems and components, by providing an overview of technical considerations required to develop, implement, and manage a foreign material exclusion program at CNE Cernavoda Unit 1 and 2 Nuclear Power Station. It is also described an example of Foreign Material Intrusion which happened during the 2003 planned maintenance outage at Cernavoda Unit no.1. This paper also defines personnel responsibilities and key nomenclature and a means for evaluating prospective work tasks and activities against standardized criteria, in order to identify the appropriate level of the required FME controls. (author)

  1. Foreign Material Exclusion Program at CNE Cernavoda Nuclear Generating Station

    Energy Technology Data Exchange (ETDEWEB)

    Urjan, Daniel [S.N. ' Nuclearelectrica' SA, CNE Cernavoda Nuclear Power Plant, Medgidiei 2 Street, 905200 Cernavoda, Constanta (Romania)

    2008-07-01

    In the face of a continuing attention to operations and maintenance costs at nuclear power plants, the future of the industry depends largely upon increasing plant availability and improving operating efficiency. The success in achieving these objectives is dependent upon the success of each plant's equipment maintenance program. Preventing the introduction of foreign materials into a nuclear power plant system or component requires a careful, thoughtful, and professional approach by all site personnel. This paper describes a proactive approach to prevent the introduction of foreign material into systems and components, by providing an overview of technical considerations required to develop, implement, and manage a foreign material exclusion program at CNE Cernavoda Unit 1 and 2 Nuclear Power Station. It is also described an example of Foreign Material Intrusion which happened during the 2003 planned maintenance outage at Cernavoda Unit no.1. This paper also defines personnel responsibilities and key nomenclature and a means for evaluating prospective work tasks and activities against standardized criteria, in order to identify the appropriate level of the required FME controls. (author)

  2. Integrity Analysis of Turbine Building for the MSLB Using GOTHIC code for Wolsong NPP Unit 2

    International Nuclear Information System (INIS)

    A break in the piping between the steam generators and the turbine can lead to rapid loss of secondary circuit inventory. A break inside the turbine building leads to pressure differentials between different areas of the turbine building. In order to improve the environmental protection of various components within the turbine building, a wall has been erected which effectively separates the area in which these components are housed from the rest of the turbine building. Relief panels installed in the turbine building ensure that the pressure differential across the wall would be less than that required to jeopardize the wall integrity. The turbine building service wing is excluded from the scope of this analysis. It is further assumed that any doors in the heavy wall are as strong as the wall itself, with no gaps or leakage around the doors. For the full scope safety analysis of turbine building for Wolsong NPP unit 2, input decks for the various objectives, which can be read by GOTHIC 7.2a, are developed and tested for the steady state simulation. The input data files provide simplified representations of the geometric layout of the turbine building (volumes, dimensions, flow paths, doors, panels, etc.) and the performance characteristics of the various turbine building subsystems

  3. Integrity Analysis of Turbine Building for the MSLB Using GOTHIC code for Wolsong NPP Unit 2

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Bong-Jin; Jin, Dong-Sik; Kim, Jong-Hyun; Han, Sang-Koo [ACT, Daejeon (Korea, Republic of); Choi, Hoon; Kho, Dong-Wook [KHNP-CRI, Daejeon (Korea, Republic of)

    2015-05-15

    A break in the piping between the steam generators and the turbine can lead to rapid loss of secondary circuit inventory. A break inside the turbine building leads to pressure differentials between different areas of the turbine building. In order to improve the environmental protection of various components within the turbine building, a wall has been erected which effectively separates the area in which these components are housed from the rest of the turbine building. Relief panels installed in the turbine building ensure that the pressure differential across the wall would be less than that required to jeopardize the wall integrity. The turbine building service wing is excluded from the scope of this analysis. It is further assumed that any doors in the heavy wall are as strong as the wall itself, with no gaps or leakage around the doors. For the full scope safety analysis of turbine building for Wolsong NPP unit 2, input decks for the various objectives, which can be read by GOTHIC 7.2a, are developed and tested for the steady state simulation. The input data files provide simplified representations of the geometric layout of the turbine building (volumes, dimensions, flow paths, doors, panels, etc.) and the performance characteristics of the various turbine building subsystems.

  4. Mounting the large-size building blocks of the reactor room structure at the Kozloduj NPP fifth power unit (Bulgaria)

    International Nuclear Information System (INIS)

    Pecularities of the construction of Kozloduj NPP fifth power unit with a WWER-1000 reactor are described. Methods of mounting reactor well, storage pond and underwater reloading well using large-size building blocks are presented. The described methods can be applied for the construction of NPPs with WWER-1000 reactors using a high capacity crane (not less than 200 t) erected in the centre of the reactor building

  5. Simplified model of the safety relief valves in the steam generator compartment of NPP Kozloduy Units 1-4

    International Nuclear Information System (INIS)

    The safety relief valves in the Steam Generator Compartment (SGC) ensure the protection against overpressurization of the Steam Generator Sealed Compartments in the 1-4 units of Kozloduy NPP. The specifics of the valve construction makes difficult the use of the currently existing codes. A simplified operational model of the relief valves is worked out. The results of the performance of this model for analysis of SGC parameters using CONTAIN 1.1 code are presented. (author)

  6. Accident analysis of Fukushima Daiichi NPP Unit-1 with SAMPSON code

    International Nuclear Information System (INIS)

    The progress of the core disruption of the Fukushima Daiichi NPP Unit-1 was analyzed by the severe accident analysis code SAMPSON. The code includes new modellings of the phenomena that occurred which have been deemed specific to the Fukushima Daiichi NPP: (1) steam leakage from the gasket of the safety relief valve (SRV) and from the buckling portion of the guide tubes (GTs) of some in-core monitors (source range monitors (SRMs) and intermediate range monitors (IRMs)): (2) melting of SRM/IRM GTs at the bottom of the reactor pressure vessel (RPV); and (3) incorporation of continuous drainage pathways for debris relocation. During the early phase of the accident after the reactor scram, the isolation condensers (ICs) had intermittently worked until the loss of AC and DC power supplies by the tsunami. The analysis reproduced well the RPV pressure transient during the IC operation period. After the loss of AC and DC power supplies, the SRV had repeated its opening and closing to keep the RPV pressure constant at about 7.5 MPa for about 4.5 hours, resulting in a gradual decrease of water level in the core. Then the SRV stopped working due to depressurization by the direct steam release from the buckling portions of the SRM/IRM GTs and from the SRV gasket. The eutectic B4C (control rod material) and steel reacted, resulting in the initiation of melting at about 4.5 h after the scram when the collapsed water level was getting closer to the bottom of active fuel, followed by melting of steel, zircalloy, and eutectics of UO2+Zr. All 12 SRM/IRM GTs had sequentially melted at about 6.5 h after the scram, resulting in fall down of melts onto the pedestal floor. Since there was no intentional core cooling for about 14 hours after the termination of the ICs until the alternative water injection by a fire engine, the core disruption continued. When the alternative water injection was started at 05:46, March 12 (15 h after the scram), 85% of the core materials had already become

  7. Numerical Analysis for the Accident at Spent Fuel Bay Cooling and Purification System of Wolsong NPP Unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sook Kwan; Kim, Kyoung Hyun; Kim, Koo Sam; Han, Sang Koo [Hanbat National Univ., Daejeon (Korea, Republic of)

    2014-05-15

    The main purpose of SFB(Spent Fuel Bay) cooling and purification system is to remove decay heat of spent fuels and to maintain concentration of radioactivity. Like Fukushima Daiichi nuclear disaster in 2011, loss of heat sink at SFB can lead to a critical situation. However it is also true that there is much more time available for operators to act responses to the accident at SFB compared with design basis accidents related to the reactor core occurring in the nuclear power plant. In this analysis, pipe rupture in the SFB cooling and purification system in Wolsong NPP Unit 1, the most severe accident at SFB, was analyzed to calculate the time of boiling and the time at which fuels are uncovered. The estimated times may be used for HRA (Human Reliability Analysis) of PSA. The accident in the SFB cooling and purification system of Wolsong NPP unit 1, specifically pipe rupture downstream SFB pumps, was analyzed using RELAP5/MOD3.3. The nodalization was developed based on the actual SFB cooling and purification system. The analysis of pipe rupture downstream SFB pumps for normal and abnormal conditions was performed to calculate major times, particularly the time of boiling and fuel uncovery. The predicted overall behaviors are reasonable. Thus the method developed in the analysis can be applied to support Wolsong NPP Unit LPSD PSA activities.

  8. Implementing Data Acquisition Systems DAS1 and DAS2 at Cernavoda Full-Scope Simulator Main Control Room based on the SIEN2007 solution

    International Nuclear Information System (INIS)

    Modern personnel training, re-training and licensing is a guarantee of NPP's safe reliable operation. Cernavoda NPP personnel training system is the main objective of its specialized department built up as Training Center (TC), directly supervised by Administration of the National Nuclearelectrica Society (SNN) and National Regulatory Body for Nuclear Activities (CNCAN). It was implemented to ensure the abilities, skills and knowledge required by the safe reliable operation of the nuclear reactor by the Main Control Room (MCR) operators. This objective was reached through training lessons taught and tested on the Full Scope Simulator (FSS), the TC's main training tool, a replica of the MCR of the real plant. Its description is the subject of this paper. The TC's FSS includes a computer network equipped with a software connected to the specialized program DATAPATH supplied for Cernavoda FSS by the FSS provider, delivered by L-3/ MAPPS. An alternative to DATAPATH Communication of the L 3/MAPPS Simulation System, developed by Cernavoda Full Scope Simulator Staff, was presented in the previous edition of the symposium (see the SIEN 2007 paper). This original solution is now already applied in order to connect to simulation process Data Acquisition Systems DAS1 and DAS2, two new systems already installed in the real MCR but not included by the Cernavoda FSS initial design. Communication between simulation software and DAS1 and DAS2, considered to be simple receivers of simulated data both as much alike as the two DASs from real plant, is performed in parallel with DATAPATH in a safe mode and without affecting simulation process. This paperwork presents the above mentioned application of this communication solution, developed by the Cernavoda NPP Full Scope Simulator Staff with details about the hardware/software solutions and their performance, training impact, cost and benefits. (authors)

  9. The management of safety within the completion of units 3. and 4. in NPP Mochovce

    International Nuclear Information System (INIS)

    The contribution defines the way of management of safety and protection of health and protection against the fire during completion of units 3. and 4. in NPP Mochovce. The creation of the management of safety raised from the legal and other requirements applied in the civil activities and mainly from the requirements for coordination of safety on the site. The whole system is methodically managed through the 5 basic documents so-called 'Building rules': 1) Safety-technical conditions of performance in SE, Inc. Bratislava (project MO34); 2) MO34/1/MNA-003.00-02 the elaboration of the integrated safety plan; 3) MO34/1/NA-003.00-03 risks analyse; 4) PNM3460100 Integrated safety plan for completion of Units 3.and 4 in NPP Mochovce; 5) Project of construction organization. The system itself of the management of the safety prevention must by provided by the supplier in compliance with the standard OHSAS 18 001 and ISO 14001, and in compliance with the requirement of the builder applied in the technical specification for the contract. Most of necessary related documentation of Safety plan for the site is usually part of the documentation for quality management of contractor. Therefore it is necessary to put the reference in each chapter of the Safety plan for site and the standpoint how to apply it for the particular specific situation. The coordinator is mandatory to manage the prevention for the part of safety of specified site and to coordinate the activity of suppliers during the works tie in this way, that the each contractor shall meet the safety requirements given by safety plan and also to identify and to eliminate the risks menaced in the particular work places or the suppliers each other. The builder established its own control system and for this purpose he settled the data base so-called 'The system of corrective and precautionary activities'. The system registers in its data base all discrepancies determined during the regular controls of the head workers

  10. Comparisons between the extensive radiological measurements made during start up of units I and II of the CNAAA NPP

    International Nuclear Information System (INIS)

    Integrated tests (IT) applied to the Units I and II of the CNAAA NPP (Angra dos Reis, Rio de Janeiro) were part of the comprehensive test programme to which the plants were submitted before authorization for commercial operation is issued. The so called IT tests included operation at zero power and subsequent power levels (the power escalation) until the nominal operation power. This paper reports and compares the results of systematic neutron and gamma dose-rate measurements performed inside and outside the reactor containment of the units, during the start-up phase of the operation of the plants, for different power levels of the reactors. (author)

  11. RELAP5/MOD3.2 sensitivity calculations of loss-of-feed water (LOFW) transient at Unit 6 of Kozloduy NPP

    Energy Technology Data Exchange (ETDEWEB)

    Pavlova, M.P. [Institute for Nuclear Research and Nuclear Energy, Tzarigradsko Shaussee 72, Sofia 1784 (Bulgaria)]. E-mail: pavlova@inrne.bas.bg; Groudev, P.P. [Institute for Nuclear Research and Nuclear Energy, Tzarigradsko Shaussee 72, Sofia 1784 (Bulgaria)]. E-mail: pavlinpg@inrne.bas.bg; Stefanova, A.E. [Institute for Nuclear Research and Nuclear Energy, Tzarigradsko Shaussee 72, Sofia 1784 (Bulgaria)]. E-mail: antoanet@inrne.bas.bg; Gencheva, R.V. [Institute for Nuclear Research and Nuclear Energy, Tzarigradsko Shaussee 72, Sofia 1784 (Bulgaria)]. E-mail: roseh@inrne.bas.bg

    2006-02-15

    This paper provides a comparison between the real plant data obtained by Unit 6 of Kozloduy nuclear power plant (NPP) during the loss-of-feed water (LOFW) transient and the calculation results received by RELAP5/MOD3.2 computer model of the same NPP unit. RELAP5/MOD3.2 computer model of the VVER-1000 has been developed at the Institute for Nuclear Research and Nuclear Energy-Bulgarian Academy of Sciences (INRNE-BAS) based on Unit 6 of Kozloduy NPP. This model has been used for simulation the behavior of the real VVER-1000 NPP during the LOFW transient. Several calculations have been provided to describe how the different boundary conditions reflect on the prediction of real plant parameters. This paper discusses the results of the thermal-hydraulic sensitivity calculations of loss-of-feed water transient for VVER-1000 reactor design. The report also contains a brief summary of the main NPP systems included in the RELAP5 VVER model and the LOFW transient sequences. This report was possible through the participation of leading specialists from Kozloduy NPP and with the assistance of Argonne National Laboratory (ANL) for the United States Department of Energy (US DOE), International Nuclear Safety Program (INSP)

  12. The evaluation of residual resource of the technological channels of the 1-st ChNPP's unit

    International Nuclear Information System (INIS)

    The result of study of the technological channels (TC) of the 1-st Chernobyl NPP's unit after 18 years of operation are analyzed in this work. It is showed that zirconium alloy of TC operated at normal conditions has satisfactory plastic and strength properties; hydrogen concentration doesn't exceed 60 ppm; the joint devices have safety factor more 2 even at presence of microcracks. The conclusion is done that residual resource of normal operating TC after 18 years of service doesn't still exhaust

  13. Modeling the migration of 90Sr and 137Cs in the subsurface from the Chernobyl NPP Unit-4 Shelter

    International Nuclear Information System (INIS)

    The Shelter constructed above the destroyed Unit-4 of the Chernobyl NPP contains 20 MCi of nuclear fuel. More than 1,000 m3 of intermediate-level radioactive water is disposed in its basement. The purpose of this work was to simulate migration of the radionuclides 90Sr and 137Cs from the Shelter into the subsurface environment to evaluate their migration rate and migration paths. A mathematical model accounting for the coupled transport of water and radionuclides in variably saturated media was used. The lack of suitable experimental and field studies excluded the possibility of complete validating the model. Results of the simulations will be useful for future field studies

  14. Conceptual model of the 'blast furnace' version of formation of nuclear-dangerous accumulation on the Ch NPP Unit 4

    International Nuclear Information System (INIS)

    Basic provisions of conceptual model of the 'blast furnace' version of formation of nuclear-dangerous accumulation of the fuel containing materials (FCM) hidden in a zone of pro-melting of a under-reactor slab of the Chernobyl NPP Unit 4 are formulated. Formation of the fragments of the former core (FFC) with a critical mass of uranium and lava-like FCM is considered as a result of two interconnected processes - molten core/concrete interactions and melting of FFC in a bathtub of silicate fusion that was formed of the materials 'furnace charges'

  15. Main Results and Conclusions of Probabilistic Safety Analysis (PSA) Level 1 for Units 5 and 6 of ''Kozloduy'' NPP

    International Nuclear Information System (INIS)

    In accordance with international practice, probabilistic safety analysis (PSA) is an established tool for studying the main risk aspects of the design and operation, to explore the importance of plant modifications and evaluation of events plant experience. Different PSA applications are very useful and flexible tool in addition to deterministic analysis. PSA can be used to optimize the different plant configurations, for justification or basis for modification of limiting conditions for operation (LCO), for planning of maintenance activities, to provide engineering evaluations in decisions making process as well as to control and monitoring the safety. This paper presents the main results and conclusions from the last update of PSA level 1 for 5 and 6 units of ''Kozloduy'' NPP. This study shows the measures of ''modernization program'' 5 and 6 units of ''Kozloduy'' NPP, realized in the period 2001-2007. PSA level 1 is performed by the team of Risk Engineering. This paper shows the main contributors to the risk. The results for internal initiating events, earthquakes, internal flooding and internal fires are given.(author).

  16. Possibilities of self-starting of the electric motors for own needs of the fifth unit of the Kozloduj NPP

    International Nuclear Information System (INIS)

    A characteristic feature of the existing electric power users' supply system of the Kozloduy NPP is that the emergency transformers serve both the 5th and 6th units. This circuit assures high reliability of the electric motors' self-starting, if no preliminary charge is included. For improving the process of self-starting in such a case the following measures are proposed: uniform distribution of the charge towards the sections; implementation of new variants of circuits in the systems for own needs, e.g. with four transformers with a single power of 40 MW; currentless pause at self-starting not higher than 1 s; in case of simultaneous operation of the 5th and 6th units the voltages of the working emergency transformers should be kept on the maximum permissible level. 4 tabs, 3 figs, 2 refs

  17. Probabilistic safety analysis of the Kozloduy NPP units 1-4 (WWER-440/230) using independent emergency feedwater system

    International Nuclear Information System (INIS)

    The safety of the Kozloduy NPP is being promoted by backfitting and improved operational practice. Special measures mitigating potential severe accidents consequences are needed because of some deficiencies in the original design of the four WWER-440 units. In conditions of a total LOCA (Loss Of Coolant Accident) it is impossible to ensure decay heat removal using the existing safety system. In such cases an extra emergency feedwater system independent of the plant's other systems has been introduced which offers a new alternative means of removing the residual heat from the reactor. A probabilistic safety analysis is carried out using the method of event trees. A comparison between the existing safety system and the newly proposed is made. The simulation results of the unit behaviour prove that the damage frequency of the active zone is lower with the new system. 3 refs., 3 tabs., 2 figs

  18. Implementation of Romanian NPP spent fuel management strategy. A regulatory approach

    International Nuclear Information System (INIS)

    The NPP Cernavoda Unit 1 started operation in 1996, producing around 100 t spent fuel per year. Unit 2 is under construction and restart of construction of Unit 3 is considered. After considering different options, it was found that the best strategy for the management of the NPP spent fuel is the dry storage for at least 50 years, with further possible extension of the dry storage period. This option allows for the time necessary for siting, construction and commissioning of the Romanian geological disposal of the spent fuel, if another more favourable option will not occur meantime. The paper describes the regulatory framework that governs the spent fuel management and details the regulatory process, presenting the main requirements formulated by CNCAN, by regulatory dispositions and authorization conditions, as well as the system of inspections at the site during the construction phase. The last part of the paper presents some considerations related to geological disposal of spent fuel. Romania is a relatively small country, and subject to earthquakes. Nevertheless, the Government considers that siting a geological repository within the country is necessary for secure implementation of the nuclear programme. However, considering the benefits that an international repository can present, Romania would like to keep such an option open, under the condition that international safety and security standards are met and regulatory control at the receiver country is established. (author)

  19. Final results and improvement proposals of the analysis of internal flooding in the reactor building of Kozloduy NPP Unit 6

    International Nuclear Information System (INIS)

    For modernization of Units 5 and 6 of the Kozloduy NPP, a comprehensive analysis of internal flooding scenarios has been carried out for the reactor building outside the containment and for the turbine hall by FRAMATOME ANP and ENPRO Consult. The objective of the presentation is to provide information on the main results obtained in the flooding analysis of the Reactor Building (outside Containment). The flooding analysis is being performed under application of the 'Methodology and boundary conditions'. Flooding calculations are provided for all of the rooms in the reactor building outside the containment in which the fluid systems, having the capacity for flooding, are mounted. The performed functional analysis shows, whether the consequences of a postulated initial event are within the NPP design or could lead to situations which are not taken into account in the design. The proposals for overcoming of identified unacceptable situations and the possible strategy of room draining are also given. Several cases of leaks inside of sealed rooms in the restricted area lead to the situation that the rooms will get totally flooded. Even if this should be acceptable from the point of view of loss of system function, the water pressure effect on the structural elements, as walls and doors, does not allow such complete filling-up. The second relevant identified effect was spreading of humidity and high temperatures to adjacent rooms. Long-lasting effects of this type have to be avoided, in order to prevent potential common cause effects on safety system equipment. (authors)

  20. QUABOX/CUBBOX Code Validation For The Calculations Of The Ignalina NPP 1 Unit Reactor Core Composition Changes

    International Nuclear Information System (INIS)

    At present, at the Ignalina NPP the process of a wider use of the new uranium-erbium fuel is going on. The loading process of the new uranium-erbium fuel assemblies into the reactor cores is accompanied by experiments and analytical investigation of the behaviour of the main neutron-physical characteristics of the reactors. The article presents the results of independent calculations of different core states of the reactor of the 1 unit of the Ignalina NPP, obtained using the German code QUABOX/CUBBOX. Ale data are compared with the results of similar calculations performed using the codes SADCO and STEPAN, as well as with experimental data. This is one of the further steps in the process of validation of the code QUABOX/CUBBOX. This article is a continuation of the discussion of the results of calculations performed in the process of verification of the German code QUABOX/CUBBOX for the modeling of the processes taking place in RBMK-1500 reactors. (author)

  1. Main results of the analysis of internal flooding in the reactor building of Kozloduy NPP Unit 6

    International Nuclear Information System (INIS)

    For modernization of Units 5 and 6 of Kozloduy NPP, a comprehensive analysis of internal flooding scenarios has been carried out for the reactor building outside the containment and for the turbine hall by FRAMATOME ANP and ENPRO Consult. The objective of the presentation is to provide information on the main results obtained in the flooding analysis of the reactor building (outside containment). The flooding analysis is being performed under application of the 'Methodology and boundary conditions'. Flooding calculations are provided for all of the rooms in the reactor building outside the containment in which the fluid systems, having the capacity for flooding, are mounted. The performed functional analysis shows whether the consequences of a postulated initial event are within the NPP design or could lead to situations which are not taken into account in the design. The proposals for overcoming of identified unacceptable situations and the possible strategy of room draining are also given. Several cases of leaks inside the sealed rooms in the restricted area lead to the situation that the rooms will get totally flooded. Even if this should be acceptable from the point of view of loss of system function, the water pressure effect on the structural elements, as walls and doors, does not allow such complete filling-up. The second relevant identified effect was spreading of humidity and high temperatures to adjacent rooms. Long-lasting effects of this type have to be avoided, in order to prevent potential common cause effects on safety system equipment (authors)

  2. Assessment of the feasibility of an improvement programme enabling operation of units 3 and 4 of Kozloduy NPP

    International Nuclear Information System (INIS)

    The report describes the assessment of the existing WWER/440/230 reactors at the Kozloduy NPP by identifying the main lacks in their design. This assessment has shown that the current safety level is not sufficient. The scope of requirements is established keeping in mind that this NPP might not be stopped in the next few years. A dedicated assessment of the feasibility of an improvement program has been undertaken by Institute for Protection and Nuclear Safety (IPSN) in this scope and includes extension of reference accidents, reactor pressured vessel, confinement, protection against internal and external hazards, large 'primary to secondary' leaks, qualification and ageing. This assessment can be extended to other plants of WWER/440/230. In conclusion IPSN experts consider that if a modernization program would be achieved, the main topics presented above should be highlighted. In such a case it would need in depth investigations some items related to: the present status of the vessels specifically for unit 3, the residual life time of important equipment such as I and C, the effects of the uncertainties on calculated radioactive releases, the approach to be followed for several accidents

  3. PLATON and SPV programme - means of improving reliability of cernavoda NPPs

    International Nuclear Information System (INIS)

    A data-acquisition system for plant information named PLATON is connected to the plant digital control computers and allows inspection of trends, bar charts, alarms and hard copies of main control room displays. It allows the construction of historical trends of process variables. PLATON helps plant expertise be quickly focused during plant transients and is a good tool in emergency exercises. SPV means 'Single Point of Vulnerability' project in Cernavoda NPP. The main goal of the SPV initiative is to reduce to as low a level as possible the vulnerability of the plant to events as a result of failures of equipment representing SPV. The experience gained during this initiative development will be used to improve the plant preventive maintenance programme. (author)

  4. Example of Environmental Monitoring Approaches: Case of the Cernavoda Nuclear Power Plant. Annex IV

    International Nuclear Information System (INIS)

    An example of a monitoring programme is provided and its constituents is taken from the Cernavoda operational monitoring of Canada deuterium-uranium (CANDU) reactor units 1 and 2 (heavy water moderated reactors). Routine Environmental Radiation Monitoring Programme: The purpose of a routine environmental radiation monitoring programme is to provide reliable and accurate data, including statistically valid datasets for significant nuclide and environmental media on an annual basis. The monitoring programme is designed to meet the following objectives under normal nuclear power plant operating conditions: (a) To measure the radionuclide concentrations in environmental media and to assess the increased radiation levels in specified environmental pathways, which might be modified as a result of the Cernavoda nuclear power plant operation; (b) To provide an independent assessment of the effectiveness of the source control, effluent control and monitoring based on measurements in the environment; (c) To validate the models and parameters used to calculate the derived emission limits (DELs); (d) To demonstrate the negligible environmental impact of the Cernavoda nuclear power plant operation and, hence, to contribute to public reassurance; (e) To provide data to aid in the development and evaluation of models and methodologies that adequately describe the movement of radionuclides through the environment

  5. Methodology and boundary conditions applied to the analysis on internal flooding for Kozloduy NPP units 5 and 6

    International Nuclear Information System (INIS)

    Within the Modernization Program of Units 5 and 6 of Kozloduy NPP a comprehensive analysis of internal flooding has been carried out for the reactor building outside the containment and for the turbine hall by FRAMATOME ANP and ENPRO Consult. The objective of this presentation is to provide information on the applied methodology and boundary conditions. A separate report called 'Methodology and boundary conditions' has been elaborated in order to provide the fundament for the study. The methodology report provides definitions and advice for the following topics: scope of the study; safety objectives; basic assumptions and postulates (plant conditions, grace periods for manual actions, single failure postulate, etc.); sources of flooding (postulated piping leaks and ruptures, malfunctions and personnel error); main activities of the flooding analysis; study conclusions and suggestions of remedial measures. (authors)

  6. Burn-out and isotope structure of nuclear fuel in lavas of 4-th unit Ch NPP

    International Nuclear Information System (INIS)

    In article the question on legitimacy of application of the relation 134Cs/137Cs for definition of a degree of burn-out of the fulfilled nuclear fuel in lava like fuel contained mass (LFCM) broken down of 4-th unit ChNPP is considered. This method is compared to this purpose with other independent methods of account of burn-out. In particular, precision the analysis of the chosen samples LFCM was carried out with use of a method isotope dilution with alpha- and mass-spectrometer measurement of the isotope relations in plutonium and uranium. Is shown, that use of cesium relation for calculation of burn-out is quite allowable. The man powers at definition of this value received by results a gamma-spectrometric analysis of samples, do not go in any comparison with expenditure of labour of all other methods. 6 refs., 10 tab., 2 figs

  7. Validation of six-loop RELAP5 model of VVER-440/V213 unit with transients measured in the Paks NPP

    International Nuclear Information System (INIS)

    In the AGNES project a six-loop input model of then third unit of the Paks NPP has been developed for the RELAP5/mod2 computer code. To verify that model, transients measured in Paks NPP were chosen for simulation: trip of main circulating pump and scram after a spurious signal from the safety system. The analyses of the transients show that, with only a very few modifications in the input model, the results are in a good agreement with the measured data. (author)

  8. Project Management Unit for decommissioning of NPP Bohunice VI (2003-2014); Project Management Unit para el desmantelamiento de CN Bohunice V1 (2003-2014)

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Fernandez-conde, A.; Brochet, I.; Ferreira, A.

    2015-07-01

    From October 2003 until december 2014 the Consortium consisting of Iberdrola Engineering and Construction (leader). Empresarios Agrupados Internacional, and Indra Sistemas has carried out the project Project Management Unit ((PMU) for the decommissioning of Bohunice V1 NPP (units 1 and 2), type VVER-440/V-230 in Slovakia. during the first phase (2003-2007) EdF was also part of the Consortium. The project is funded by the Bohunice International Decommissioning Support Fund (BIDSF) administered by the RBRD. The main objective of the project is to provide the necessary engineering and resources of project management for planning, execution, management, coordination and monitoring of all tasks in support of the decommissioning. (Author)

  9. Two managerial grids in NPP

    International Nuclear Information System (INIS)

    Today, the nuclear power corporation (NPC) enjoys the profit of LCEP (the low carbon economic policy). at the same time, they also enduring more and more pressure. For example, the partner competition or the NPP potential occupational risk . The efficient counterplot of risk is the self-ability cultivation. It is essential to research the NPP managerial flow. The nuclear power plant (NPP) unit is a carrier of the NPC enterprise management system, and has taken on a new look 'pull one portion then the whole moving'. The NPP has three systematical characters, the security responsibility center, the man-machine system and the input-output system. The manufacturing system and the enterprise management system are the great constituents of the NPP managerial flows. Means of systems analysis, we can find out the truth of the NPP running interface. In CHINA, there are many operating experiences near 20 years. It indicates that the NPP manufacturing system and the enterprise system are the roots of the nuclear power corporation, the core of the all NPP systems must be based on it. So the ability cultivation is the work core to NPP. It is reliably to ensure the NPP to be up against problems, for instance, the security duty, the costing control and the man-machine system running harmoniously. This paper introduces the NPP managerial flow and the present state of QNPC, also come up with a proposal to refer for the NPC development actions of collective measure, specialization, standardization, fine. (author)

  10. Strategic maintenance plan for Cernavoda steam generators

    International Nuclear Information System (INIS)

    Steam generators are among the most important pieces of equipment in a nuclear power plant. They are required full time during the plant operation and obviously no redundancy exists. Past experience has shown that those utilities which implemented comprehensive steam generator inspection and maintenance programs and strict water chemistry controls, have had good steam generator performance that supports good overall plant performance. The purpose of this paper is to discuss a strategic Life Management and Operational-monitoring program for the Cernavoda steam generators. The program is first of all to develop a base of expertise for the management of the steam generator condition; and that is to be supported by a program of actions to be accomplished over time to assess their condition, to take measures to avoid degradation and to provide for inspections, cleaning and modifications as necessary. (author)

  11. Experience of radiation management in the removal work of RTD bypass lines at Kori NPP unit no. 3 and 4

    International Nuclear Information System (INIS)

    RTD bypass lines in reactor coolant system are critical system for providing the necessary temperature signal to the reactor control and protection system. In case of a leakage of RTD bypass lines, the plant shutdown and the over-exposure of maintenance workers could occur. So the removal of RTD bypass lines were performed for the reliable and safe operation of the plant and the installation work of direct temperature measurement instruments for the fast response temperature detection was also performed in the reactor coolant system. Through the ALARA experience at Kori NPP unit 3 and 4 (950 MWe, 3 loops), Youngkwang N/P and Ulchin N/P could also adopt this experience to reduce the radiation exposure. Then the collective radiation exposure, man-rem could be minimized and the radiation production could be also reduced satisfactorily. Actual collective radiation exposure was 38.7 man-rem for Kori unit no. 3 and 25.4 man-rem for the Kori unit no.4.. (author)

  12. Annex V. Project re-start management experience Mochovce unit 3 and 4 NPP, Slovak Republic

    International Nuclear Information System (INIS)

    The purpose of this report is to describe the re-starting phase of DNPP MO 34 Project, mainly focusing on management issues. The report consists of three main parts dealing with the Project management organization during the three different periods of the of DNPP re-starting process. The first part (Chapter 2) begins with the general background information about the NPP and then focuses on the pre-feasibility and feasibility study. The second part (chapter 3) deals with the current status of the plant and it stresses the main steps of the DNPP Project resuming after completion of the feasibility study. The third part (Chapter 4) outlines the main issues related to the criticality of a typical DNPP Project (e.g. preservation and maintenance of equipments, updating to technological and regulatory requirements, human resources, protection of design documentation, etc.) and the measures implemented in MO 34. The hereby presented content reflects the experience and good practices concerning the following main management issues: - project control measures; - human resources; - preservation and maintenance of site installations, structures and equipment; - updating of the whole Project to meet licensing requirements and technology upgrades; - preservation of Project documentation. (author)

  13. Beta project: Some preliminary results of PSA level 2 for Unit 1 of Kalinin NPP

    International Nuclear Information System (INIS)

    The goals of this project are: transferring methodology of PSA level 1 and 2 performance to GAN and support of Russian organizations and development of probabilistic model of the Kalinin NPP-1 WWER-1000. SAPHIRE 7.19 and MELCOR 1.8.5 software tools are used. The main PSA level 1 results, for example: transients - 33.8%, primary LOCAs inside containment (sump clogging and no sump clogging) - 41.2% and 19.0%, total CDF (Core Damage Frequency) for all initial event groups - 2.43x10-5 (including of ATWS (Anticipated Transient Without Scram) 3.24x10-5) ect. are presented. An example of PSA level 1 event tree and Plant Damage State (PDS) matrix are given. Specific design features for severe accident progress and used nodalization for MELCORE like in-vessel modeling, MCL modeling, secondary side modeling, containment modeling are listed and illustrated. The main results of MELCORE analysis (fraction of I release and fraction of Cs release) are also presented

  14. Flooding countermeasures in Peach Bottom NPP and decommissioning of Zion unit 1 and 2

    International Nuclear Information System (INIS)

    JSME delegation visited Peach Bottom NPS and Zion NPS in February, 2013. The Peach Bottom unit 1 was constructed almost the same time Fukushima Daiichi unit 2. Zion unit 1 and 2 were under decommissioning, when we visited the NPSs. Both the NPSs were good practice for in Japan. (author)

  15. Control of NPP aging processes

    International Nuclear Information System (INIS)

    The concept of the control program on the NPP aging processes is considered. The methodological algorithms for the working programs plotting and realization, intended for accomplishing the measures for mitigating the aging mechanisms and factors, effecting the NPP safety, are presented. The efficiency of the equipment for the aging processes control and power units systems, aimed at the control of the NPP service life, is analyzed

  16. Maintenance optimization methods for NPP critical systems, structures and components

    International Nuclear Information System (INIS)

    Considerable progress has been made in the development and implementation of the plant life management (PLiM) program with formal processes to identify systematically and evaluate the major critical systems, structures and components (CSSCs) in the station, and a plan to ensure that the plant surveillance, operation, and maintenance programs monitor and control component degradation well within the original design specifications essential for the plant life attainment. The paper presents a brief description of most important aspects of the methods used to identify the CSSCs taking into account maintenance activities. The system structures and components (SSCs) that influence decisively the NPP reliability are considered as critical. Also, for the accident conditions, the SSCs, which have a major influence to the system availability/operability, are considered also as critical. PSA techniques serve as a basis for maintenance optimization. In the paper a case of association between operating events and CSSC is presented. The main reference was the PSA study for Cernavoda NPP, Unit 1 CPSE B+. From this study it was selected and presented: - the contribution diagram for the occurrence of one accident (small LOCA) with some severe consequence (e.g. PDS 1 - 2 - early core damage); - dominant accident sequence analyzed; - the initial event that generated the possible dominant sequence; - the most important accident events; - qualitative and quantitative results; - main CSSC identification; - results validation and proposals for system operation performance improving; - documentation of the analysis. For the critical components, if periodical maintenance operations are needed, the maintenance activities must be optimized. In order to ensure these, some sensitivity studies have to be performed. In the system probabilistic models the associated events for the critical components could be the failure events of the components and also the unavailability due to component

  17. Radioactive waste management at nuclear power plant Cernavoda

    International Nuclear Information System (INIS)

    Many human activities generate waste, but people are worried about wastes produced in nuclear power plants (NPPs). Their concern is an unjustified fear toward the hazards from radioactive waste, probably because in any country generating electric power by NPPs a lot of attention is paid to relevant parties involved in radioactive waste management. Significant attention is also given to the management of radioactive waste at the Cemavoda NPP. The general approach required for the collection, handling, conditioning and storage of radioactive wastes, while maintaining acceptable levels of safety for workers, members of the public and the environment, is conceptually established. The overall programme provides the necessary facilities to adequately manage solid radioactive waste from Cemavoda NPP Unit 1 and will be capable of expansion when other units are brought into service. (author)

  18. TBN repair in Ulchin N.P.P. unit 2, KEPCO, Korea

    International Nuclear Information System (INIS)

    Ulchin unit 2, the ninth nuclear unit in Korea, is located in Ulchin-gun, Kyeong-buk, southeast of Korean peninsular. This unit is a 950 MWe class PWR type nuclear unit with its NSSS (Nuclear Steam Supply System) supplied by Framatome and turbine and generator sets by Alsthom of France. Since its first synchronization in April, 1989, these have been three times of major turbine related failure instances. The unit is currently running at full load after repair works of high pressure and low pressure turbines, while the indepth analysis and evaluation works to clarify the root cause of those failures are in progress. In this paper, the nature of the failures and repair works are presented. (author)

  19. Change of secondary water regime of Paks NPP. Change of secondary water regime at Unit 2

    International Nuclear Information System (INIS)

    The installation of high pH water regime during the 17th cycle of Unit 2 aimed to decrease the amount of transportation inlet of erosion-corrosion products (magnitude) in feedwater to SGs. The resolution of OAH-NBI permitting the installation ordained to make an evaluation of the process. The main conclusions and results are discussed. The high pH water regime proved to be adequate in the case of Unit 2 as well, similarly to Units 3, 4 and 1. (R.P.)

  20. Fabrication and erection of special building structures at the Rovno NPP third unit

    International Nuclear Information System (INIS)

    It is described how works on fabrication and erection of special building structures in the reactor section, a special building and a stand-by diesel-generator station at the Rovno Unit-3 are organized

  1. Preparation for Ignalina NPP decommissioning

    International Nuclear Information System (INIS)

    Latest developments of atomic energy in Lithuania, works done to prepare Ignalina NPP for final shutdown and decommissioning are described. Information on decommissioning program for Ignalina NPP unit 1, decommissioning method, stages and funding is presented. Other topics: radiation protection, radioactive waste management and disposal. Key facts related to nuclear energy in Lithuania are listed

  2. Application of safety standards and rules in the Shelter Implementation Plan at the destroyed power unit of Chernobyl NPP

    International Nuclear Information System (INIS)

    This report deals with the application of safety standards and rules to the Shelter Implementation Plan (SIP) measures. Since 1998 this plan is being implemented at the Chornobyl NPP destroyed unit (which is now known as the Shelter). It includes a set of various tasks whose performance will help partially achieve the established safety objectives. The Regulatory Authority should establish for the Shelter safety goals, principles, and criteria in general, while the Operator of the Shelter is free to independently select the optimum method for their implementation. The Operator of the Shelter must demonstrate (in safety analysis report) that established safety goals are achieved and safety principles and criteria are met. Safety goals, principles, and criteria established for radioactive waste management are reasonable to apply in measures provided for by SIP. However, due to the unique nature of the Shelter, some criteria should not be applied directly and in full scope. Norms and rules on radiation protection should be applied in full scope. The specifics of radiation protection during each Shelter-related activity are considered individually. Safety standards and rules related to technical aspects are reasonable only as a basis. Effective resolution of specific technical issues associated with safety assurance is achieved through interaction between the Operator and the Regulatory Authority during design of SIP structures and systems. Hence, effectiveness of the licensing process plays an important role in the success of the SIP.(author)

  3. Supervision of Operation Safety at Ignalina NPP

    International Nuclear Information System (INIS)

    Description of VATESI supervision functions during operation and maintenance of Ignalina NPP is presented. Comparison of collective exposure dose of Ignalina NPP and other organizations with previous years is made. The number of emergency outings of Ignalina NPP units during the years is presented

  4. Kozloduy NPP units 5 and 6 modernization program. Measures implementation in outages

    International Nuclear Information System (INIS)

    The units 5 and 6 modernization program is a highly demanding program composed by many plant modifications and studies about plant conditions. The program measures implementation during the units outages represents a challenge by the need to compromise shut down duration with the workload related to measures installation. The units shutdown duration should be kept to the planned duration. In parallel, contractors work has to be organized, planned and performed to allow successful measures completion. In accordance with the contract requirements, contractors prepare installation documents which comprise all activities to be performed during the installation and testing of the measures. The subcontractors complement these installation documents with the project organization and execution documents, which include the manpower skills, qualifications, work orders, and other important installation instructions and information. Contractors prepared detailed installation schedules, and these were integrated by Parsons E and C in the Integrated installation schedule. The integrated schedule proved to be useful to identify possible area usage conflicts and manpower overlapping, with appropriate results for electrical, instrumentation and control work, and for the utilization of the polar crane in the containment building. Contractors installation schedules were updated on a weekly basis, showing variances versus the target, and manpower histograms for the resource loading. Organization of contractors work was supported by KNPP plant outage meetings, in which status and problems were addressed, and solution and/or corrective actions defined for further implementation. KNPP meetings were planned on a daily basis for most relevant or critical measures, or on a weekly basis for less intensive measures. KNPP meetings proved to be an excellent communication tool for keeping the measures under control and monitoring KNPP defined personnel responsible for authorizing changes, in

  5. Operating and reconstruction experience of the drum-separators of the Kursk NPP unit 1

    International Nuclear Information System (INIS)

    The reason for increased humidity at the drum-separator outlet is determined analyzing separation tests and data on the power unit equipment operation. It is shown that hydrovalve breakup at the outlet of the submerged punched sheet was the source of the high steam humidity. Recommendations on the hydrovalve reconstruction and separation test results after the reconstruction are presented. The separated steam humidity does not exceed 0.02% by the mass at the nominal unit parameters at 52 mm height of the hydrovalve outlet gap

  6. Introduction of nitrogen blow-through in the cooling circuit of the Chernobyl NPP Unit 3 in experimental industrial use

    International Nuclear Information System (INIS)

    Analysis of nuclide composition of Chernobyl NPP releases (inert gases) showed that Ar-41 plays there the main role (84-90%). For its decrease a system for gas tank blow-through by nitrogen of high purification was proposed

  7. VERONA-U upgrading the core-monitoring system at unit 2 of Paks NPP

    International Nuclear Information System (INIS)

    Title words of transparencies shown at the meeting are reproduced on the reactor monitoring automatic system VERONA. Complete text is missing. The outline comprises data of Unit 2 of Paks Nuclear Power Plant, deficiencies of the present system, signals processed, new data collection system, data of host computers, improved core analysis, hot-spot monitoring, object-oriented database, archivation and replay, man-machine interface, main workstation functions, and the block diagram of the VERONA-U system. (N.T.) 1 fig

  8. Seismic safety review mission for the follow-up of the seismic upgrading of Kozloduy NPP (Units 1-4). Sofia, Bulgaria, 16-20 November 1992

    International Nuclear Information System (INIS)

    A Seismic Safety Review Mission for the follow-up of the design and implementation of the seismic upgrading of Kozloduy NPP was performed in Sofia from 16-20 November 1992. This mission continued the second task of the follow-up activities of the design and implementation of the seismic upgrading (Phases 1 and 2), which is being carried out in Units 1 and 2 of the NPP. Thus the objectives of the mission was to assist the Bulgarian authorities in the technical evaluation of the design tasks defined for Phases 1 and 2 item HB of WANO 6 Month Programme, as follows: anchorage upgrades of low seismic capacity components; list of seismic safety related systems and components; detailed walkdown to assess seismic capacity of components and define priorities for the upgrading; determination of seismic structural capacity of pump house, diesel generator building and turbine building and design of required upgrades; liquefaction potential evaluation. Tabs

  9. Analysis of Radioactive Material in Consideration of Containment Filtered Venting System for Wolsong NPP Unit 1

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung-Han; Kim, Jin-Hyuck; Suh, Nam Duk [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Cho, Song-Won [Nuclear Safety Evaluation, Daejeon (Korea, Republic of)

    2014-10-15

    The containment filtered venting system (CFVS) was first installed at Wolsong unit 1 in 2012. CFVS is used to prevent the build-up of excessive pressure in a reactor containment during a severe accident. When the containment pressure exceeds the design pressure of the containment building, the operator opens CFVS isolation valves. Then steam and air in the containment flows out to the environment through the CFVS and the containment pressure decreases below 150 kPa(a). In addition, the key function of CFVS is to reduce the radioactive material releasing from the containment to the environment. The aim of this study is to analyze the radioactive material in consideration of the CFVS operation for Wolsong unit1 using the MELCOR 1.8.6 code developed at Sandia National Laboratories (SNL) for the U.S. Nuclear Regulatory Commission (NRC). In addition, in order to evaluate the effects of filtration efficiencies for the filters of the CFVS, a sensitivity study according to decontamination factor (DF) of the filters was carried out. The SBO accident is chosen to analyze the release fraction of radioactive material of Wolsong unit 1 in the consideration of the CFVS operation using MELCOR 1.8.6 code. Also, a sensitivity study was carried out to evaluate the filtration performance according to decontamination factor of the filters for CFVS. The results show that the small amounts of radioactive material are slightly released to the environment except for noble gases. That is, the CFVS filtered most of aerosol form and released noble gases to the environment directly. Therefore, the CFVS has a good filtration performance to reduce radioactive material such as aerosol form. In addition, the filtration efficiencies of the filters for CFVS considerably depend on DFs according to the calculation results of CsI. However, there are no different results of Xe according to DFs because the CFVS cannot retain noble gases. In the future, a proper requirement for a criteria of

  10. Safety evaluation for communication network software modifications of PCS in Ulchin NPP unit 3

    International Nuclear Information System (INIS)

    On February 2, 1999, an incident occurred at the Ulchin Nuclear Power Plant Unit 3 which resulted in the corruption of data on Perform Net of Plant Control System. This incident was caused by the ASIC (Application Specific Integrated Circuit) chip on the Rehostable Module which is a part of Network Interface Module. Regarding this incident, we required that the utility should propose new algorithms to detect the hardware failure of ASIC chip and evaluated the appropriateness of network software modifications. As a result of this evaluation process, we required that the safety related interlock signals using data communication path be hardwired to make up for the vulnerability of the system architecture. In this paper, we will discuss the system architecture of PCS and fault analysis and evaluation findings

  11. Upgrading the SPP-500-1 moisture separators-steam reheaters used in the Leningrad NPP turbine units

    Science.gov (United States)

    Legkostupova, V. V.; Sudakov, A. V.

    2015-03-01

    The specific features of existing designs of moisture separators-steam reheaters (MSRs) and experience gained with using them at nuclear power plants are considered. Main factors causing damage to and failures of MSRs are described: nonuniform distribution of wet steam flow among the separation modules, breakthrough of moisture through the separator (and sometimes also through the steam reheater), which may lead to the occurrence of additional thermal stresses and, hence, to thermal-fatigue damage to or stress corrosion cracking of metal. MSR failure results in a less efficient operation of the turbine unit as a whole and have an adverse effect on the reliability of the low-pressure cylinder's last-stage blades. By the time the design service life of the SPP-500-1 MSRs had been exhausted in power units equipped with RBMK-1000 reactors, the number of damages inflicted to both the separation part and to the pipework and heating surface tubes was so large, that a considerable drop of MSR effectiveness and turbine unit efficiency as a whole occurred. The design of the upgraded separation part used in the SPP-500-1 MSR at the Leningrad NPP is described and its effectiveness is shown, which was confirmed by tests. First, efforts taken to achieve more uniform distribution of moisture content over the perimeter and height of steam space downstream of the separation modules and to bring it to values close to the design ones were met with success. Second, no noticeable effect of the individual specific features of separation modules on the moisture content was revealed. Recommendations on elaborating advanced designs of moisture separators-steam reheaters are given: an MSR arrangement in which the separator is placed under or on the side from the steam reheater; axial admission of wet steam for ensuring its uniform distribution among the separation modules; inlet chambers with an extended preliminary separation system and devices for uniformly distributing steam flows in the

  12. Westinghouse experience in Kozloduy NPP units 5 and 6 I and C modernization

    International Nuclear Information System (INIS)

    The paper presents the background, current implementation approach and experience on the largest ever modernization program on operating units WWER 1000 (PWR) at Kozloduy Nuclear Power Plant in Bulgaria. The Modernization Program itself includes more than 212 measures. Westinghouse is modernizing the major I and C systems at WWER 1000. The major topics of the modernization program and specific approach described in this paper are as follows: 1) Design Approach and Feature; 2) Installation Approach; 3) Test Strategy; 4) Licensing Strategy, applicable codes and standards. At the end author summarized that: 1) Specific design solutions were required and developed in order to address the specific plant features. At each stage, representatives of the Client are being involved in the process of designing and testing of the equipment and systems; 2) Phase-by-phase installation efforts were developed and extensive installation design documentation was prepared to fit in the limited outage window and to successfully complete the installation activities; 3) Well-prepared, multi-phase testing strategy was developed and is being implemented to assure the proper and adequate operation of the equipment at the factory and at the real plant

  13. Examination of steam generator alloy 800 NG tube from the Almaraz unit 2 NPP

    International Nuclear Information System (INIS)

    The steam generators of Almaraz Unit 2 were replaced in 1997 by the model 61W/D3 (Siemens) with Alloy 800NG steam generator tubes. Denting indications were firstly detected in 2006 in the SG-3. Crack indications were identified in 2009. At the end of 2011, three tubes were recovered from this steam generator to carry out destructive examination in order to identify the root cause of the tubes degradation. Analysis of deposits point out the existence of multiples elements in the removed OD (Outer Diameter) deposits as well as in the deposits at the free tube under sludge and at the transition zone. Deposits are more abundant at the transition zone than at free tube. About 10% Na concentration has been detected, whereas S and Cl appear in small concentrations. Si appears regularly and Cr, Ni concentrations in the deposits are similar. Multiple intergranular cracks have been detected at 3 mm above the last contact point between the tube and the TS (tube support), in a band of around 5 mm, practically in the whole perimeter of the tube. Fracture surface of crack-B was partially covered by a Si rich layer, whereas fracture surface of crack-A seems to be cleaner. However, no significant differences in composition, except higher amount of S in crack-B, were found in the deposits of both cracks. EDX mapping and Auger profiles point out Ni enrichment with slight Cr enrichment or depletion and Fe depletion. The comparison of Auger profiles with available results for Alloy 800 tested in caustic and acid sulfate environments seems to indicate that the environment inside the cracks detected in the tube R67C48 is neutral or moderately caustic

  14. Capacity assessment of the containment structure of units 5 and 6 at Kozloduy NPP

    International Nuclear Information System (INIS)

    The containment structure of the reactor building is made of a post-stressed concrete shell with a steel liner. The post tension cables (tendons) are anchored in a stiff ring girder at the junction of the cylinder shell with spherical dome. The wall thickness is variable for different zones of the cylinder and the dome. Two finite element models are developed to study the structural behaviour of the containment. The first one is composed as a stick model and is used for seismic response analysis of the containment structure including the effects of soil-structure interaction. The second one is detailed finite element shell model of the containment including inclined arrangement of the prestressing cables. It is used for the study of linear and non-linear static and dynamic responses of the containment under loads due to normal operation, additional loads due to the anticipated operational occurrences and some additional loads due to accident conditions. Assessment of the bearing capacity of the structure is done along with a study of failure modes in critical load combinations. The evaluation of the prestressing of the containment is made by investigating the prestressing technology, as well as the on-line scanning of the prestressing using embedded sensors and annual verification of prestressing by control of tendon stresses during operation of the unit. Comparison of this evaluations with the finite element model analyses results will help to tune the model and assess the reliability of the non-destructive control/monitoring system of the containment. (author)

  15. Basic measures for the improvement of the safety, realized in the NPP 'Kozloduy' units 1-4

    International Nuclear Information System (INIS)

    Measures for the improvement of the safety of the units 1-4 of the NPP 'Kozloduy' have been implemented, taking into account the main safety principles and directed to the following activities: analyses; fuel cooling; radioactive products location; assurance of the containment and primary circuit integrity; improvement of the plant operation. Some of the main measures applied are: installation of relief valves; replacement of the safety valves of the steam generators; installation of a safety isolation kit for the pressurizer; construction of emergency feedwater system; installation of breakers; fire system. This has been performed as a complex program, leading to a significant improvement of the safety. One of the main problems is the impossibility of guaranteeing of an adequate protection of the components in the control room in case of common cause failure. It is assumed that the installation of relief valves together with an antiseismic construction's reinforcement can prevent from a local recriticality in case of a secondary circuit rupture and the reactor's isolation. High pressure in the steam generator is avoided by the installation of new relief valves in the steam generators, functioning as steam dump to atmosphere and they are capable to ensure the reactor cooling to a cold state. In order to properly perform the 'feed and bleed' procedure it is installed an independent water supply system. The results after the improvements according to the probabilistic safety analysis show that core melt frequencies of the units 3-4 and 1-2 are 7.9.10-5 and 8.1.10-5 respectively versus ∼ 10-3 before the reconstruction. After the installation of new valves and the realization of the 'feed and bleed' procedure the primary circuit safety is increased 5 times. The problems of containment safety and cold overpressurization are solved in case of reactor stop and shutdown and accident. The independent water supply system increases the reactor safety in 20% and permits 'f

  16. Results of reconstruction of in-core outlet coolant temperature measurements at V-230 reactors, Unit 1 and 2 NPP Bohunice

    International Nuclear Information System (INIS)

    During the reconstruction of NPP V 1 Bohunice units with V-230 reactors, all in-core temperature measuring systems were upgraded. All measuring channels including thermocouples up to data acquisition system were replaced. The report provides the objectives, process and results of the reconstruction. Accuracy and reliability of the in-core measurements were enhanced, and their resistance to accident environment was achieved. Moreover metrological assurance and automatic self-check of accuracy with the temperature etalon of reactor measurements were achieved. The obtained quality of the in-core temperature measurements exceeds that of similar systems in V-213 reactors. (Authors)

  17. The primary circuit materials properties results analysis performed on archive material used in NPP V-1 and Kola NPP Units 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Kupca, L.; Beno, P. [Nuclear Power Plants Research Institute Inc., Trnava (Slovakia)

    1997-04-01

    A very brief summary is provided of a primary circuit piping material properties analysis. The analysis was performed for the Bohunice V-1 reactor and the Kola-1 and -2 reactors. Assessment was performed on Bohunice V-1 archive materials and primary piping material cut from the Kola units after 100,000 hours of operation. Main research program tasks included analysis of mechanical properties, corrosion stability, and microstructural properties. Analysis results are not provided.

  18. Development and verification of a leningrad NPP unit 1 living PSA model in the INL SAPHIRE code format for prompt operational safety level monitoring

    International Nuclear Information System (INIS)

    The first part of the paper presents results of the work, that was carried out in complete conformity with the Technical Assignment, which was developed by the Leningrad Nuclear Power Plant. The initial scientific and technical information, contained into the In-Depth Safety Assessment Reports, was given to the author of the work. This information included graphical Fault Trees of Safety Systems and Auxiliary Technical Systems, Event Trees for the necessary number of Initial Events, and also information about failure probabilities of basic components of the nuclear unit. On the basis of this information and fueling it to the Usa Idaho National Laboratory (INL) SAPHIRE code, we have developed an electronic version of the Data Base for failure probabilities of the components of technical systems. Then, we have developed both the electronic versions of the necessary Fault Trees, and an electronic versions of the necessary Event Trees. And at last, we have carried out the linkage of the Event Trees. This work has resulted in the Living PSA (LPSA - Living Probabilistic Safety Assessment) Model of the Leningrad NPP Unit 1. The LPSA-model is completely adapted to be consistent with the USA INL SAPHIRE Risk Monitor. The second part of the paper results in analysis of fire consequences in various places of Leningrad NPP Unit 1. The computations were carried out with the help of the LPSA-model, developed in SAPHIRE code format. On the basis of the computations the order of priority of implementation of fire prevention measures was established. (author)

  19. The seismic reassessment Mochovce NPP

    International Nuclear Information System (INIS)

    The design of Mochovce NPP was based on the Novo-Voronez type WWER-440/213 reactor - twin units. Seismic characteristic of this region is characterized by very low activity. Mochovce NPP site is located on the rock soil with volcanic layer (andesit). Seismic reassessment of Mochovce NPP was done in two steps: deterministic approach up to commissioning confirmed value Horizontal Peak Ground Acceleration HPGA=0.1 g and activities after commissioning as a consequence of the IAEA mission indicate higher hazard values. (author)

  20. Safety assessment of Olkiluoto NPP units 1 and 2. Decision of the Radiation and Nuclear Safety Authority regarding the periodic safety review of the Olkiluoto NPP

    International Nuclear Information System (INIS)

    In this safety assessment the Radiation and Nuclear Safety Authority (STUK) has evaluated the safety of the Olkiluoto Nuclear Power Plant units 1 and 2 in connection with the periodic safety review. This safety assessment provides a summary of the reviews, inspections and continuous oversight carried out by STUK. The issues addressed in the assessment and the related evaluation criteria are set forth in the nuclear energy and radiation safety legislation and the regulations issued thereunder. The provisions of the Nuclear Energy Act concerning the safe use of nuclear energy, security and emergency preparedness arrangements, and waste management are specified in more detail in the Government Decrees and Regulatory Guides issued by STUK. Based on the assessment, STUK consideres that the Olkiluoto Nuclear Power Plant units 1 and 2 meet the set safety requirements for operational nuclear power plants, the emergency preparedness arrangements are sufficient and the necessary control to prevent the proliferation of nuclear weapons has been appropriately arranged. The physical protection of the Olkiluoto nuclear power plant is not yet completely in compliance with the requirements of Government Decree 734/2008, which came into force in December 2008. Further requirements concerning this issue based also on the principle of continuous improvement were included in the decision relating to the periodic safety review. The safety of the Olkiluoto nuclear power plant was assessed in compliance with the Government Decree on the Safety of Nuclear Power Plants (733/2008), which came into force in 2008. The decree notes that existing nuclear power plants need not meet all the requirements set out for new plants. Most of the design bases pertaining to the Olkiluoto 1 and 2 nuclear power plant units were set in the 1970s. Substantial modernisations have been carried out at the Olkiluoto 1 and 2 nuclear power plant units since their commissioning to improve safety. This is in line with

  1. Development and overall testing of the traditional MTC estimation based on noise diagnostics at all four units of the Paks NPP

    International Nuclear Information System (INIS)

    Highlights: → Development of the traditional noise based estimators applied in VVER-440 reactors. → Considering the effect of propagating perturbations, geometry and coolant velocity. → Compensating the frequency response of the slow thermocouples. → Investigations at all four units of the Paks NPP during whole fuel cycles. → Estimations were quite close to the reference values (10-40% difference). - Abstract: Moderator Temperature Coefficient (MTC) of reactivity is an important parameter of nuclear reactors and its value should be in a specific range during the reactor operation. Determining MTC with traditional methods is performed through deviating the reactor state from the normal operation. Noise diagnostics has the potential to provide an MTC estimation method during normal operation without changing the reactor state. This paper overviews the developments made on the traditional noise based estimators and the steps of their application in VVER-440 type reactors. Modifications were made to consider the effect of propagating perturbations through geometry and coolant velocity and to compensate the frequency response of the slow thermocouples. Frequency dependence of H1 was calculated in high resolution which involved the revision of the method applied for reading the MTC value earlier (see the details in ). Investigations were performed at all four units of the Paks NPP to verify the dependence of the results on specific core features (e.g. on core loading patterns) and instrumentation of the individual units. For a better comparison of the results, a common frequency range of the evaluation was chosen for all units, thus this range was made narrower and its weight went closer to the frequency range affected by power feedback. Absolute values of the estimated MTC are smaller than the reference value due to the effect of feedback and low coherence. During the investigated fuel cycles estimations were quite close to the reference for two units (the

  2. Nuclear power plant life management: Strategy for long term operation of the Beznau NPP unit 1 and 2

    International Nuclear Information System (INIS)

    Full text: Both Beznau nuclear power plants (KKB) are of the Westinghouse two loop PWR type with a rated electrical output of 380 MWel and have been operated on base load demand since 1969 and 1972 respectively. The design base uses rather conservative assumptions. By performing selective measures, such as large investments in backfitting, the safety of the plants has been continuously enhanced. Through focussed modernisations and careful maintenance, the overall condition of both Units is excellent. A comprehensive ageing management programme (AMP) for all safety related structures, systems and components (SSC) was set up and started 15 years ago, according to the requirements of the Swiss Federal Nuclear Safety Inspectorate (HSK). The AMP contains all essential actions of evaluation and control of the ageing concerning the material and also conceptual aging. The permanently increasing demand for electrical energy in Switzerland, as well as economic factors, led NOK to evaluate long term operation (LTO) of KKB. Beside hydro power, nuclear power covers 40% of the demand in Switzerland. A new nuclear law in Switzerland allows unlimited operation of a NPP as long as safety goals are met. The performed analysis and conclusions for a potential LTO is presented in the paper, including aspects such as technical issues, fuel, radwaste, elusive risks, personnel management and economics to assure LTO with the best achievable safety level. The necessary actions to address and control the ageing mechanisms of the civil structures have been established in line with the AMP. The procedures for implementing these actions are in place and are continuously executed. The technical feasibility for the essential actions required for a LTO up to 60 years is given. A systematic registration of the actions to control ageing of all electrical systems and components occurs in line with the AMP. The main challenge is not the material related ageing but the availability of products and

  3. Seismic qualification of distribution board for Kozloduy NPP, units 5 and 6, by analytical method and by analogy

    International Nuclear Information System (INIS)

    This abstract presents the basic approach for seismic qualification by analysis of a distribution board for fire dampers control at Kozloduy NPP WWER-1000 MW Reactor Buildings - Units 5 and 6. The distribution board is a steel cabinet with mounting plate inside it on which are mounted all the components. For this qualification are used results from preliminary tested on uniaxial seismic platform distribution board with smaller dimensions, but with the same components mounted in it. The smaller board passed successfully the seismic tests and stayed functional after the seismic excitation specified with the prescribed Required Response Spectra (RRS). The seismic qualification by analytical method of the distribution board begins with an overview of the input data used for the analysis, including the RRS and Test Response Spectra (TRS) of preliminary tested distribution board with smaller dimensions. Detailed 3D computer model of the preliminary tested board and comparison between the test results and the results derived by analytical methods are done. For getting more precise modelling, very detailed evaluation of the components (material, mass, location, way of fixture etc.) is made. The mesh of shell and frame elements is suitably selected to describe the behaviour of the board during the seismic tests. Way of fixing of the tested board to the seismic platform is evaluated and properly modelled. Calculated damping for registered by test resonance frequencies of the board is used for adjusting the modal damping in the model. The acceleration time history registered on the seismic platform for selected seismic level is used as an input excitation for the model of the tested board. Calibration of the modelled and the tested distribution board is done by comparison of the generated TRS for given direction of excitation, for selected points at height of the tested board for given damping from one side and Response Spectra (RS) for the same direction of excitation, the

  4. Organization of operator interface in on-line control systems of high-power TPP and NPP units

    International Nuclear Information System (INIS)

    Organization for interaction of an operator-technologist of a high-power TPP or NPP with hard- and software of on-line control systems is considered. The interface efficiency is provided with: rational selection and grouping necessary for operator data and control organs during designing the system; optimization of distribution of data and control organs in the number of stages of access to them; on-line selection of actual in a given moment data, which is fulfilled by a system during its auctioning

  5. Evaluation of specific tritium transfer parameters in equilibrium conditions for Cernavoda area

    International Nuclear Information System (INIS)

    In Romania, a CANDU nuclear power plant with five reactors of 600 MWe is under construction. The first unit reached its criticality on April 1996 and became operational at full power on December 1996. The nuclear power plant is placed in Cernavoda area, in the S-E of Romania, between the Danube River and the Danube-Black Sea Canal. The prevalent local climate is continental and agricultural activity in the neighbourhood of the nuclear power plant is of intensive type. The routine atmospheric tritium release from the 3 GWe nuclear power plant is expected to be about 460 TBq/year and the aqueous release is expected to be 350 TBq/year. The aim of this study was to evaluate the environmental tritium reference level before commissioning the nuclear power plant. Representative samples for Cernavoda area were analysed: air humidity; water from Danube River, Danube-Black Sea Canal, lakes; drinking and ground water, rain (snow) water; soil at different depths; tissue free water tritium in vegetal and animal foodstuff relevant for human diet: cereals (wheat, maize, barley), vegetables (potato, tomato, cabbage, onion, bean), fruits, grapes, wine and milk; organically bound tritium in wheat and maize grains. The equipment and methods used were: Liquid scintillation analyzer of type TRICARB 1900 TR; scintillation cocktails of Instagel and Pico Fluor LLT type; sampling system for trapping the atmospheric tritium on molecular sieves; furnace; vacuum line and freeze trap (-60 deg. C); equipment for simple, fractionating and azeotropic distillation. The background level of tritium concentration was determined in environmental samples in Cernavoda area, in preoperational stage of nuclear power plant. The mean values determined during 1994-early 1996 are : (7.4±5.5) Bq/L in air humidity, (3.1±1.0) Bq/L in water, (3.53±0.4) Bq/L in tissue water from vegetable and (4.9±1.7) Bq/L in tissue water from cereals (grains). The values of tritium concentration in air, water, soil and

  6. Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 3G. Kozloduy NPP units 5/6: Analysis and testing. Working material

    International Nuclear Information System (INIS)

    In August 1991, following the SMiRT-11 Conference in Tokyo, a Technical Committee Meeting was held on the 'Seismic safety issues relating to existing NPPs'. The Proceedings of this TCM was subsequently compiled in an IAEA Working Material. One of the main recommendations of this TCM, called for the harmonization of criteria and methods used in Member States in seismic reassessment and upgrading of existing NPPs. Twenty four institutions from thirteen countries participated in the CRP named 'Benchmark study for the seismic analysis and testing of WWER type NPPs'. Two types of WWER reactors (WWER-1000 and WWER-440/213) selected for benchmarking. Kozloduy NPP Units 5/6 and Paks NPP represented these respectively as prototypes. Consistent with the recommendations of the TCM and the working paper prepared by the subsequent Consultants' Meeting, the focal activity of the CRP was the benchmarking exercises. A similar methodology was followed both for Paks NPP and Kozloduy NPP Unit 5. Firstly, the NPP (mainly the reactor building) was tested using a blast loading generated by a series of explosions from buried TNT charges. Records from this test were obtained at several free field locations (both downhole and surface), foundation mat, various elevations of structures as well as some tanks and the stack. Then the benchmark participants were provided with structural drawings, soil data and the free field record of the blast experiment. Their task was to make a blind prediction of the response at preselected locations. The analytical results from these participants were then compared with the results from the test. Although the benchmarking exercises constituted the focus of the CRP, there were many other interesting problems related to the seismic safety of WWER type NPPs which were addressed by the participants. These involved generic studies, i.e. codes and standards used in original WWER designs and their comparison with current international practice; seismic analysis

  7. Beyond designed functional margins in CANDU type NPP. Radioactive nuclei assessment in an LOCA type accident

    Directory of Open Access Journals (Sweden)

    Budu Andrei Razvan

    2015-01-01

    Full Text Available European Union's energy roadmap up to year 2050 states that in order to have an efficient and sustainable economy, with minimum or decreasing greenhouse gas emissions, along with use of renewable resources, each constituent state has the option for nuclear energy production as one desirable option. Every scenario considered for tackling climate change issues, along with security of supply positions the nuclear energy as a recommended option, an option that is highly competitive with respect to others. Nuclear energy, along with other renewable power sources are considered to be the main pillars in the energy sector for greenhouse gas emission mitigation at European level. European Union considers that nuclear energy must be treated as a highly recommended option since it can contribute to security of energy supply. Romania showed excellent track-records in operating in a safe and economically sound manner of Cernavoda NPP Units 1&2. Both Units are in top 10 worldwide in terms of capacity factor. Due to Romania's need to ensure the security of electricity supply, to meet the environmental targets and to move to low carbon generation technologies, Cernavoda Units 3&4 Project appears as a must. This Project was started in 2010 and it is expected to have the Units running by 2025. Cost effective and safety operation of a Nuclear Power Plant is made taking into consideration functional limits of its equipment. As common practice, every nuclear reactor type (technology used is tested according to the worse credible accident or equipment failure that can occur. For CANDU type reactor, this is a Loss of Cooling Accident (LOCA. In a LOCA type accident in a CANDU NPP, using RELAP/SCDAP code for fuel bundle damage assessment the radioactive nuclei are to be quantified. Recently, CANDU type NPP accidents are studied using the RELAP/SCDAP code only. The code formerly developed for PWR type reactors was adapted for the CANDU geometry and can assess the

  8. Chernobyl NPP accident. Overcoming experience. Acquired lessons

    International Nuclear Information System (INIS)

    This book is devoted to the 20 anniversary of accident on the Chernobyl NPP unit 4. History of construction, causes of the accident and its consequences, actions for its mitigation are described. Modern situation with Chernobyl NPP decommissioning and transferring of 'Ukryttya' shelter into ecologically safe system are mentioned. The future of Chernobyl site and exclusion zone was discussed

  9. Strain measurement and analysis for the RPV of Qinshan NPP (unit I) at primary system hydrostatic test

    International Nuclear Information System (INIS)

    Hydrostatic test for RPV (Reactor Pressure Vessel) is not only a means to inspect the vessels and the associated systems but also an important way to verify the results of mechanical analysis. The loading obtained by measurement is useful for the establishment of loading spectrum. Some discussions on the shop hydrostatic test planning for the RPV of Qinshan NPP (Nuclear Power Plant) performed in Japan are presented. Comparisons between the results of hydrostatic test provided by vendor and those of primary system hydrostatic test conducted at Qinshan Site are also given. Some data obtained at Qinshan Site such as actual loading and technical data of the stud-bolt, are listed. The results of measurement for the flange rotation, important for the sealing characteristics of RPV, are specifically discussed. The authors point out some of the mistakes in the results of the shop hydrostatic test

  10. Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 3F. Kozloduy NPP units 5/6: Analysis and testing. Working material

    International Nuclear Information System (INIS)

    In August 1991, following the SMiRT-11 Conference in Tokyo, a Technical Committee Meeting was held on the 'Seismic safety issues relating to existing NPPs'. The Proceedings of this TCM was subsequently compiled in an IAEA Working Material. One of the main recommendations of this TCM, called for the harmonization of criteria and methods used in Member States in seismic reassessment and upgrading of existing NPPs. Twenty four institutions from thirteen countries participated in the CRP named 'Benchmark study for the seismic analysis and testing of WWER type NPPs'. Two types of WWER reactors (WWER-1000 and WWER-440/213) selected for benchmarking. Kozloduy NPP Units 5/6 and Paks NPP represented these respectively as prototypes. Consistent with the recommendations of the TCM and the working paper prepared by the subsequent Consultants' Meeting, the focal activity of the CRP was the benchmarking exercises. A similar methodology was followed both for Paks NPP and Kozloduy NPP Unit 5. Firstly, the NPP (mainly the reactor building) was tested using a blast loading generated by a series of explosions from buried TNT charges. Records from this test were obtained at several free field locations (both downhole and surface), foundation mat, various elevations of structures as well as some tanks and the stack. Then the benchmark participants were provided with structural drawings, soil data and the free field record of the blast experiment. Their task was to make a blind prediction of the response at preselected locations. The analytical results from these participants were then compared with the results from the test. Although the benchmarking exercises constituted the focus of the CRP, there were many other interesting problems related to the seismic safety of WWER type NPPs which were addressed by the participants. These involved generic studies, i.e. codes and standards used in original WWER designs and their comparison with current international practice; seismic analysis

  11. Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 3H. Kozloduy NPP units 5/6: Analysis and testing. Working material

    International Nuclear Information System (INIS)

    In August 1991, following the SMiRT-11 Conference in Tokyo, a Technical Committee Meeting was held on the 'Seismic safety issues relating to existing NPPs'. The Proceedings of this TCM was subsequently compiled in an IAEA Working Material. One of the main recommendations of this TCM, called for the harmonization of criteria and methods used in Member States in seismic reassessment and upgrading of existing NPPs. Twenty four institutions from thirteen countries participated in the CRP named 'Benchmark study for the seismic analysis and testing of WWER type NPPs'. Two types of WWER reactors (WWER-1000 and WWER-440/213) selected for benchmarking. Kozloduy NPP Units 5/6 and Paks NPP represented these respectively as prototypes. Consistent with the recommendations of the TCM and the working paper prepared by the subsequent Consultants' Meeting, the focal activity of the CRP was the benchmarking exercises. A similar methodology was followed both for Paks NPP and Kozloduy NPP Unit 5. Firstly, the NPP (mainly the reactor building) was tested using a blast loading generated by a series of explosions from buried TNT charges. Records from this test were obtained at several free field locations (both downhole and surface), foundation mat, various elevations of structures as well as some tanks and the stack. Then the benchmark participants were provided with structural drawings, soil data and the free field record of the blast experiment. Their task was to make a blind prediction of the response at preselected locations. The analytical results from these participants were then compared with the results from the test. Although the benchmarking exercises constituted the focus of the CRP, there were many other interesting problems related to the seismic safety of WWER type NPPs which were addressed by the participants. These involved generic studies, i.e. codes and standards used in original WWER designs and their comparison with current international practice; seismic analysis

  12. Studies about level of ageing related to isolation of cables used in Cernavoda NPP

    International Nuclear Information System (INIS)

    The use of equipment and cables shown that after a period of operation in normal operational conditions, some modifications of physical, mechanical and electrical properties occur, which are caused by the materials ageing. The paper treats the cables ageing problems, and specifies some methods for observation and some evaluations techniques of 'health condition', of life time for signal and supply electrical cables, in the operating conditions specific to CANDU nuclear power plants. The paper presents the tests performed on Cross -Linked Poly Ethylene (XLPE) and Ethylene Propylene Rubber (EPR) isolation using sequential exposures to thermal stress and radiation. The influence of ageing level on elongation at break (EAB) is also presented. (authors)

  13. Upgrade of the audio/video recording system on the Cernavoda NPP simulator

    International Nuclear Information System (INIS)

    The audio-video recording system is used in the simulator control room for: - recording simulator examinations used for authorization or reauthorization of the operators or for ordinary training sessions; - detailed observation of the real-time actions of the operators as they operate controls on various sections of the control boards; - post-scenario analysis and critique of operator performance. The technical solution chosen for this project was to use a special PC that functions as a Digital Video Recorder (DVR). This PC contains a special purpose video and sound card, which enables the DVR functionality

  14. Models and calculation hypotheses for hydraulics analysis of the fire extinguishing water system in Cernavoda NPP

    International Nuclear Information System (INIS)

    Fire extinguishing system utilizing hydrants from Reactor Building is interfaced with the fire extinguishing system from the Service Building. The installation is permanently under 93 MPa pressure while the temperature is that of the environment. The installation consists of carbon-steel pipes with various diameters, insulations, fittings and interior fire hydrants. Regardless of the calculation scheme of fire in the turbine zone or fire in nuclear zone, the most unfavorable situations concerning the location of hydrants and rings distance to the water pumping station was considered. Calculation formulas for the hydraulic resistance are given as a function of equipment pressure loss, density and fluid speed through the equipment. PIPENET code was used for calculations in case of 90 angle bends and 45 angle bends and separate calculations were done for bends of other different angles in the system, Therefore, the total bend resistance coefficient was determined as a sum of the local resistance coefficients, and the distributed resistance coefficients. A description of PIPENET code for flow of single phased fluids, both gases and liquids is given. Its features are: - Large number of input and output values; - Nets comprising any ramification and loop arrangement; - Systems in closed loop or open loop; - Incompressible and compressible fluids; - Fixed and variable temperature fluids; - Fittings and pipe dimensions according to catalogs, or specially defined by the user. The section 4 describes creation of a PIPENET network consisting of pipes, tubing, pumps, vents, filters, etc. and the links between them. Finally, a description of the calculation model for the reactor building is given

  15. Tritium - intake and clearance. Verification of ICRP Model based on Cernavoda NPP individual monitoring data

    International Nuclear Information System (INIS)

    Operating experience to date of CANDU reactors has indicated that the major contributor to the internal dose is the tritium oxide. Special consideration of routine individual monitoring for internal exposure of workers to tritium oxide is necessary. Data on many humans have indicated that a single exponential essentially describes the retention of tritiated water over the first months or more following the intake. A typical value of the effective half time for tritium is 10 days. Lower tritium effective half-lives, 5.43 and 6.55 days, respectively, were observed in case of internal contamination if diuresis was accelerated. The dose factor for tritiated water incorporation was calculated as a function of the ICRP model parameters. The principal objectives of individual monitoring for intakes of radionuclides are: - to obtain an assessment of the committed effective dose; - to contribute to the control of operation and the design of the plant; - in the case of accidental exposure, to provide valuable information for the initiation and support of any appropriate health surveillance and treatment. Exposure to an atmosphere contaminated by tritiated water results in intake of that substance both by inhalation and by absorption through the intact skin, in a ratio assumed to be 2 to 1. Vapours of tritiated water are considered to be of SR-2 absorption class, that means the tritiated water is instantaneously absorbed into body fluids and uniformly distributed among all the soft tissues. Tritium (H-3) is a pure beta emitter, with an average energy of beta radiation of 0.0186 MeV. Its presence in the body can be detected by measuring the urine samples using the liquid scintillation counting and it presents no detection problems. (authors)

  16. Preventive maintenance program of motorized operated valves (MOV) at Cernavoda NPP

    International Nuclear Information System (INIS)

    This is a Power Point presentation. The following objectives are addressed: A. Determine the target of MOV program; B. Define the strategy for MOV; C. Establish the MOV program execution phases; D. Identification of key parameters; E. Examples. The target of MOV program is to improve the safety by ensuring the adequacy of safety valves and the reliability of safety equipment and, subsequently, to ensure the economic operation of the plant. Consequences of MV malfunction are indicated. The strategy for MOV program development is both general, namely, to define the minimal requirements of preventive /corrective maintenance activities for all MOV's according to design/ manufacture specification and particular, namely to identify MV's specific problems and the need for increasing/decreasing the preventing maintenance tasks or frequency established in 'general' MOV program. Strategy for MOV program development implies: - Establish MOV program applicability; - Develop diagnostic strategy (define key parameters ); - Perform program for engineering review; - Establish program for preventive maintenance; - Revise procedures for operating and maintenance tests; - Dynamic evaluation of MOV. The program execution phases are listed as follows: 1. Perform risk assessment of the MOV's to determine criticality level (program applicability); 2. Collect data to fill in MOV Application Data Sheet; 3. Perform engineering review to determine functional parameters acceptable range and determine key parameters; 4. Analysis for maintenance tasks / frequencies selection and determination of implementing actions (engineer review); 5. Prepare work packages for availability confirmation; 6. Schedule and plan corrective actions or provide input to other programs; 7. Schedule and plan implementing actions in preparation for program field execution; 8. Program field implementation; 9. Program monitoring, evaluation and optimization. The criteria defining the key operational and maintenance parameters are presented. Examples are given for minimum periodic maintenance tasks as well as for mechanical inspections and I - C measurements. Diagnostic sheets are also presented

  17. The impact of the internalisation of the decommissioning costs at Cernavoda NPP

    International Nuclear Information System (INIS)

    The 'decommissioning of the nuclear power plant' means to release the site where a nuclear installation has been operated in such manner that this site could be further used, without any restriction, by the present or future generations. This is an important and complex requirement related to sustainable development. The decommissioning is a complicated and costly process; therefore it is imperative to start its preparation as early as possible, to ensure the creation of the necessary financial resources and to carefully schedule all the phases to be performed after the plant's permanently shutdown. The paper presents different possible strategies for the decommissioning, recommended by the International Atomic Energy Agency-Vienna, as well as some elements of the decommissioning experience acquired in the world. Special attention is given to the issue of the financial resources which must be provided by the nuclear power plant, during its operational life, with the corresponding impact on the cost of the electrical energy delivered by the plant. The practice of the internalization of the decommissioning costs is worldwide accepted; it is an approach specific to nuclear sector, proving once more its compatibility with the environmental protection and sustainable development. The sustainable development consists in such solutions that are able to satisfy the needs of the present generation without hampering the ability of the future generations to satisfy their own needs. In the nuclear energy sector, sustainability is provided by the following specific features: (1) Nuclear energy was and shall be in the future an important factor in security of energy supply. Due to the availability of the primary energy resources (fissile and fertile materials), nuclear electricity is and shall be accessible at affordable price on a permanent and reliable basis. (2) Nuclear energy as a part of the energy mix can diminish non-renewable energy consumption, prevent the exhaustion of fossil energy resources and minimise long-term impacts of the energy industry on climate change. (3) Nuclear industry is committed to minimising environmental impacts, including the safe management of the radioactive wastes and spent fuel up to the final disposal, ensuring the safety and complying with social welfare. In this respect, all nuclear companies are committed to leave clean sites after permanently shutdown of the nuclear plants

  18. Evaluation of tritium level in Danube - Black Sea ecosystem after Cernavoda NPP commissioning

    International Nuclear Information System (INIS)

    CANDU type Nuclear Power Plant was put into service on December 1996. It will be the most powerful tritium source in Europe. Although tritium is a radioisotope with a low radiotoxicity, public opinion from Romania and especially the international public opinion are very sensitive concerning the possible emission impact on environment. So, tritium management in a CANDU Power Plant and its monitoring in surrounding ecosystem is an important part of every nuclear program. This paper presents the processing and preparing procedure of water samples with a view to determine low and ultralow tritium concentration using direct measurement with an ultralow level liquid scintillation spectrometer. All these measurements are made according to international standards. It is also presented tritium level in Nuclear Power Plant and Black Sea limitrophe zone after 20 months since the commissioning of the Heavy Water Reactor. All these data are presented and discussed comparatively with those existing before 1996

  19. Simulating the transient regime for main condensate system at Cernavoda NPP

    International Nuclear Information System (INIS)

    The purpose of this project is to make a Thermal Hydraulic Analysis of Main Condensate System for getting real-time answer of installation during regimes occurring during normal and abnormal operation. To obtain the analyses the MMS code was used. The boundaries of the systems analysis are extended to Main Feedwater System in order to get a realistic response of Deaerator equipment which are situated between those two systems and have entrances from both systems. In this way we made a complex analysis with main condenser and steam generators as boundaries. We obtained a model for the entire chain of condensate and feedwater preheater with interface just turbine bleed steam. From that we could reduce the number of assumptions necessary to make the analysis. The analyses consist in hydraulics and thermal hydraulics analyses, respectively. For the first case analysed are: - the nominal operation regime with main condensate pumps; - start-up regime with total circulate of condensate to condenser; - 25% MCR (Maximum Continuous Rate) regime (this regime was used in designing the condensate regulating valves at low flow; - 40% MCR regime (with circulate of some condensate flow to condenser); - operating regime of 60% MCR with one main condensate pump operating; - operating regime with auxiliary condensate pump; - operating regime with discharging a condensate flow to condensate storage tank. The thermal hydraulic analyses deal with normal and abnormal operating regimes, respectively. In the first case analysed are the following regimes: - nominal operating regime with main condensate pump operating 100% MCR; - transient regime, 100-80% MCR; - transient regime, 100-80-60% MCR with two pumps in operation and 60 % MCR with one main condensate pump in operation; - transient regime, 100-80-60-60-40 % MCR; - shut-down regime; - start-up regime from Hot zero power to rated power regime. Finally, for the abnormal operating regimes the analyses concerned: - transient regime 100-90% MCR with by-pass of LP1 (low pressure heater) and CC (Condensate Cooler); - transient regime, 100-90% MCR with by-pass of LP2 and LP3; - turbine trip; - reactor trip; - loss of two main condensate pumps. The results were compared with Heat Balance made by General Electric (turbine supplier) for several stationary regimes. (authors)

  20. Assessing the consequences in a nuclear accident scenario at Cernavoda NPP

    International Nuclear Information System (INIS)

    Having in view a possible nuclear incident, considerable planning is necessary to reduce at manageable levels the types of decisions leading to effective responses concerning the public protection. One of the most important parts of an emergency response plan is the computerized system which allows to predict the radiological impact of the accident and to provide information in a manageable and effective form for evaluating alternative countermeasure strategies in the various stages of the accident. In this paper the PC-COSYMA results for early containment failure of a CANDU reactor are presented. The deterministic health effects arising in nuclear accident situation are also presented. As source term we have used the core inventory obtained with ORIGEN computer code. The essential input parameters for PC-COSYMA computer code are also done. (authors)

  1. Redesign of steam generator blowdown system of Cernavoda Unit 2

    International Nuclear Information System (INIS)

    In 2005 the WANO changed the admissible values of the chemical parameters of the fluid in the steam generators to the following upper limits: - Na concentration: less than 2 μ/kg; - Cl concentration: less than 5 μ/kg; - SO4 concentration: less than 5 μ/kg. Current values from design manual of the chemical control system are: - Na concentration: less than 70 μ/kg; - Cl concentration: less than 100 μ/kg; - SO4 concentration: less than 100 μ/kg. In order to comply with the new requirements we had to increase the steam blowdown flow up to 3 times earlier operating value. We developed a system model in order to analyze system modifications and the implication to other components. One presents the required calculation steps concerning the redesign of the system that has to be operated at a higher nominal flow. The calculations requested various computational approaches such as: - Two phase flow model; - check and design calculation for regulating valves of three types: valve with liquid, gas or two phase flow inside the valve; - Flash tank; - Heat exchanger verification and design; - Flow element operating range checking. This paper presents actually the first approach of the system. At the moment we developed a stationary model of the system and the aim for the near future is to obtain a transient regime model. It will analyze the system behavior at flow changing from minimum to maximum load and especially the problems that occur at the start up of stand-by components. Currently, from operating experience of the system there are some very difficult transients during start up of stand-by heat exchanger in case that operating heat exchanger has to be isolated. (authors)

  2. Regulatory aspects of NPP safety

    International Nuclear Information System (INIS)

    Extensive review of the NPP Safety is presented including tasks of Ministry of Health, Ministry of Internal Affairs, Ministry of Environment and Waters, Ministry of Defense in the field of national system for monitoring the nuclear power. In the frame of national nuclear safety legislation Bulgaria is in the process of approximation of the national legislation to that of EC. Detailed analysis of the status of regulatory body, its functions, organisation structure, responsibilities and future tasks is included. Basis for establishing the system of regulatory inspections and safety enforcement as well as intensification of inspections is described. Assessment of safety modifications is concerned with complex program for reconstruction of Units 1-4 of Kozloduy NPP, as well as for modernisation of Units 5 and 6. Qualification and licensing of the NPP personnel, Year 2000 problem, priorities and the need of international assistance are mentioned

  3. Teledosimetry system of Mochovce NPP

    International Nuclear Information System (INIS)

    On-site monitoring posts, inner circuit there are installed 16 detectors for measuring dose rates in a circle line inside the power plant site at the distances between approximately 200 m and 520 m from the exhaust air stack of Mochovce-1,2 NPP. The technical versions of all these measuring posts are from the same type On-site are installed 3 large containers for measuring gamma dose rate and activity concentration of aerosols and iodine too. Off-site monitoring posts at places of living consist of 16 small containers with dose rate measurements and iodine sampling units and 8 large containers with dose rate measurement and aerosol and iodine monitoring unit. Three of these large containers are installed nearby the NPP inside the fence of the NPP area. The technical version of these measuring posts are from the same type. Five of these containers are installed faraway of the NPP outside the fence of the NPP. These five posts are from the same type. The process data is continuously acquired, stored and processed by the Central Radiological Computer System of the power plant. The tele-dosimetry system data are a main part of the radiological information system, which continuously provide the information of the measurements and evaluate possible radiological consequences. (author)

  4. Application of risk-informed approach to the in-service inspection programme of Unit 1 of Loviisa NPP

    International Nuclear Information System (INIS)

    The pre-service and in-service inspections (ISI) of the primary circuit components and piping of Loviisa NPP (VVER440) have been carried out since the start-up of the plant following the ISI-programme which is based on the requirements presented in the ASME Code Section XI. The latest 10 years' ISI programme was completed in 2007 and the preparation of the new ISI programme for following years was started in 2005. The basis for this new ISI programme is the new YVL-guideline issued in 2003 by the Finnish Radiation and Nuclear Safety Authority STUK. The guideline requires that utilities shall utilize risk-informed methodology when planning new ISI-programmes for safety class 1, 2, 3 and 4 as well as for non nuclear safety class classified piping systems. The approach applied in drafting the ISI-programme was in principle the same as in ASME XI Supplement R, Method B but the approach was applied for the whole plant. The consequence assessment was based on the results of existing extensive probabilistic safety assessment (PSA) analysis according to the values for Conditional Core Damage Probability (CCDP) and Conditional Large Early Release Probability (CLERP). The failure assessment was performed on a qualitative basis by a group of Fortum's experts familiar with Loviisa NPP associated materials integrity and in-service activities. The selection of elements for inspection was based on the risk categorization and identified degradation mechanisms of the piping section in concern. In addition plant specific failure types and experience with their locations were taken into account. The operational history of the plant since 1977 and the experience gained through in-service inspections and maintenance work during the years passed gave valuable additional information for the selection of items to be inspected. The new approach has brought several new features compared to the existing ISI programme. New systems, system portions and small diameter instrumentation piping of

  5. Principles of tariff determination for NPP electric power generation

    International Nuclear Information System (INIS)

    Foundations of price-setting and order of accounting arrangement for NPP electric power are considered. NPP tariffs are established proceeding from standard costs of power generation. The standards are differentiated as to NPP groups, depending on technical, regional and natural geographic factors, taking into account the facility type, unit capacity and the number of similar NPP units. The conclusion is made that under conditions of NPP economic independence expansion and creation of prerequisites for going over to self-financing principles and also due to the qualitatively new stage of nuclear power generation development the level of efficiency, forseen by the tariffs, should be increased

  6. Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 3I. Kozloduy NPP units 5/6: Analysis and testing. Working material

    International Nuclear Information System (INIS)

    In August 1991, following the SMiRT-11 Conference in Tokyo, a Technical Committee Meeting was held on the 'Seismic safety issues relating to existing NPPs'. The Proceedings of this TCM was subsequently compiled in an IAEA Working Material. One of the main recommendations of this TCM, called for the harmonization of criteria and methods used in Member States in seismic reassessment and upgrading of existing NPPs. Twenty four institutions from thirteen countries participated in the CRP named 'Benchmark study for the seismic analysis and testing of WWER type NPPs'. Two types of WWER reactors (WWER-1000 and WWER-440/213) selected for benchmarking. Kozloduy NPP Units 5/6 and Paks NPP represented these respectively as prototypes. Consistent with the recommendations of the TCM and the working paper prepared by the subsequent Consultants' Meeting, the focal activity of the CRP was the benchmarking exercises. A similar methodology was followed both for Paks NPP and Kozloduy NPP Unit 5. Firstly, the NPP (mainly the reactor building) was tested using a blast loading generated by a series of explosions from buried TNT charges. Records from this test were obtained at several free field locations (both downhole and surface), foundation mat, various elevations of structures as well as some tanks and the stack. Then the benchmark participants were provided with structural drawings, soil data and the free field record of the blast experiment. Their task was to make a blind prediction of the response at preselected locations. The analytical results from these participants were then compared with the results from the test. Although the benchmarking exercises constituted the focus of the CRP, there were many other interesting problems related to the seismic safety of WWER type NPPs which were addressed by the participants. These involved generic studies, i.e. codes and standards used in original WWER designs and their comparison with current international practice; seismic analysis

  7. Lessons learnt from the resin release into the primary circuit of the Fessenheim NPP unit 1 in January 2004. Impact on the nuclear safety

    International Nuclear Information System (INIS)

    On January the 24th, at the Fessenheim NPP unit 1, a human error was committed during a boron demineralizer line-up, caused by lack of preparation. Consequently, a quantity of resin estimated at about 300 liters was released from this demineralizer, through its safety valve, into the head-tank of the chemical and volume control (CVC) system and after that, into the primary circuit. The incident had a real impact on the unit: the CVC filters were clogged, the seal injection flow of the primary circuit main pumps was lost, the primary circuit main pump 2 tripped four days after the incident, as the rate of the recirculated seal leak flow (downstream the seal 1) increased up to the automatic trip set point, the shaft of the running primary circuit feed pump was found seized into the rear hydrostatic bearing following the pump stop (after ten days of successful operation), the thimble plugs were jammed into their guide tubes, the small diameter pipes were plugged. The unit shutdown for over five months was necessary to clean the primary circuit components, repair or replace the affected equipment items and carry out inspections and tests. The reinforced unit in-service monitoring program, set up during the unit start-up, confirms that, up to now, the unit operation has not been adversely affected by the residual amounts of resin which subsist in certain areas of the primary circuit. Nevertheless, it remains to verify that, in the long term, these deposits will have no negative chemical effect in the potential confined areas, such as the thermal barriers of the primary circuit main pumps. Finally, the occurrence of this incident underlines, once more, the importance of normal operating activity preparing and checking. It also reveals the implementation of an ''unforgiving'' design change allowing the installation of a boron demineralizer safety valve having its outlet connected to the primary circuit. (orig.)

  8. RCM at Kozloduy NPP, Bulgaria

    International Nuclear Information System (INIS)

    RCM methodology is applied within the task for Maintenance and Repair Optimization which is part of a big project started in 2005 for Optimization of maintenance using risk-informed PSA applications for Units 5 and 6 (VVER 10001320) of Kozloduy NPP. The project is still under development

  9. Analysis of safety culture at Rovno NPP

    International Nuclear Information System (INIS)

    The main concepts of safety culture which relate to safety increase in reactor unit operation, their reliable work, high qualification of personnel and personal responsibility of operators are developed. They will be introduced at the Rovno NPP

  10. Post-reconstruction full power and shut down level 2 PSA study for Unit 1 of Bohunice V1 NPP

    International Nuclear Information System (INIS)

    The level 2 PSA model of the J. Bohunice V1 NPP was developed in the RISK SPECTRUM Professional code with the following objectives: to identify the ways in which radioactive releases from the plant can occur following the core damage; to calculate the magnitudes and frequency of the release; to provide insights into the plant behaviour during a severe accident; to provide a framework for understanding containment failure modes; the impact of the phenomena that could occur during and following core damage and have the potential to challenge the integrity of the confinement; to support the severe accident management and development of SAMGs. The magnitudes of release categories are calculated using: the MAAP4/VVER for reactor operation and shutdown mode with closed reactor vessel and the MELCOR code for shutdown mode with open reactor vessel. In this paper an overview of the Level 2 PSA methodology; description of the confinement; the interface between the level 1 and 2 PSA and accident progression analyses are presented. An evaluation of the confinement failure modes and construction of the confinement event trees as well as definition of release categories, source term analysis and sensitivity analyses are also discussed. The presented results indicate that: 1)for the full power operation - there is an 25% probability that the confinement will successfully maintain its integrity and prevent an uncontrolled fission product release; the most likely mode of release from the confinement is a confinement bypass after SGTM with conditional probability of 30%; the conditional probability for the confinement isolation failure probability without spray is 5%, for early confinement failure at the vessel failure is 4%, for other categories 1% or less; 2) for the shutdown operating modes - the shutdown risk is high for the open reactor vessel and open confinement; important severe accident sequences exists for release categories: RC5.1, RC5.2 and RC6.2

  11. Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 3E. Kozloduy NPP units 5/6: Analysis/testing. Working material

    International Nuclear Information System (INIS)

    The Co-ordinated research programme on the benchmark study for the seismic analysis and testing of WWER-type nuclear power plants was initiated subsequent to the request from representatives of Member States. The conclusions adopted at the Technical Committee Meeting on Seismic Issues related to existing nuclear power plants held in Tokyo in 1991 called for the harmonization of methods and criteria used in Member States in issues related to seismic safety. The Consulltants' Meeting which followed resulted in producing a working document for CRP. It was decided that a benchmark study is the most effective way to achieve the principal objective. Two types of WWER reactors (WWER-440/213 and WWER-1000) were selected as prototypes for the benchmark exercise to be tested on a full scale using explosions and/or vibration generators. The two prototypes are Kozloduy Units 5/6 for WWER-1000 and Paks for WWER-440/213 nuclear power plants. This volume of Working material contains reports on data related to floor response spectra of Kozloduy NPP; calculational-experimental examination and ensuring of equipment and pipelines seismic resistance at starting and operating WWER-type NPPs; analysis of design floor response spectra and testing of the electrical systems; experimental investigations and seismic analysis Kozloduy NPP; testing of components on the shaking table facilities and contribution to full scale dynamic testing of Kozloduy NPP; seismic evaluation of the main steam line, piping systems, containment pre-stressing and steel ventilation chimney of Kozloduy NPP

  12. Mochovce NPP simulator

    International Nuclear Information System (INIS)

    Mochovce NPP simulator basic features and detailed description of its characteristics are presented with its performance, certification and application for training of NPP operators as well as the training scenario

  13. Visaginas NPP Project Regional Approach: Lithuania

    International Nuclear Information System (INIS)

    Lithuania has a long standing nuclear energy history. The country is the host of the Ignalina NPP consisting of two RBMK-1500 reactors (a type of boiling water reactor developed by the Soviet Union) located in Visaginas, Lithuania. Ignalina NPP (INPP) Unit 1 came online in December 1983 and Unit 2 was completed in 1987. Lithuania agreed to close the Ignalina NPP as part of its Accession Treaty to the European Union of 2003, as the Ignalina NPP design shares similarities with the Chernobyl NPP. Unit 1 was closed in December 2004 and Unit 2 was closed on 31 December 2009. Around 80% of electricity production in Lithuania in 2009 came from Unit 2 of the INPP. However, following the closure of the Ignalina NPP, Lithuanian electricity net import was 62% of the entire electricity demand in 2010 and 59%32 in 2011. To meet its energy needs following the INPP’s closure, in the absence of a new nuclear power plant, Lithuania relies on a combination of imported electricity, predominantly from interconnections with the UPS/IPS network, and power from alternative domestic generation facilities, which are predominantly fossil plants reliant on gas or oil imports from other countries

  14. Response to water hammer of Loop No. 1, including the pressurizer cold injection piping, at the Temelin NPP, Units 1 and 2

    International Nuclear Information System (INIS)

    Within the Leak Before Break analysis of the primary circuit pipeline system, it is necessary to demonstrate the resistance of the pipe system to water hammers, i.e., various high-frequency hydrodynamic events of the type of collapse of an air or steam crack (unexpected impact shock) and of an abrupt halt of a moving liquid column or vice versa (expected impact shock). The demonstration consists in analyzing the stability of a postulated circumferential pass-through crack and its fatigue growth and comparing the results with the requirements of applicable standards. The publication describes an analysis of the primary circuit of the Temelin NPP, Units 1 and 2, Loop No. 1, i.e. the 850 mm i.d. main circulation loop along with the associated pressurizer cold injection piping. Abrupt seizure of the main circulation pump rotor caused by a seismic event was chosen as the initiating event. It is shown that the water hammer can be neglected against the seismic effect. The results are generalized for Loops No. 2 through 4. (P.A.). 9 tabs., 11 figs., 5 refs

  15. Radioactive contamination of the Belarus' territory causing to destruction of the building constructions of the 4th unit of the Chernobyl NPP

    International Nuclear Information System (INIS)

    The adverse scripts of development of events, causing to destruction of object 'UKRYTIE' and to contamination of the territory of Republic of Belarus are considered. The number of designs of the 4th unit has visually observed damages. Also there are hypothetically unstable constructive elements, at installation of which in a conditions of 1986 the application of reliable welded or bolt connections was impossibly. Initial events of the considered hypothetical accident are earthquake or aircraft accident. Settlement data on contamination of territory for considered accident are indicated. The account was made for a moderate- stable condition of atmosphere by the Gauss model for process of the dust particles precipitation. In this case the radionuclide falling out will take place basically on already contaminated territory of Belarus. The additional contamination may be about 2 Ci/sq.km in the Mozyr' region and 20 Ci/sq.km in Chernobyl NPP territory. In case of imposing of acts of nature (the earthquake or tornado), the all dust fraction, which available in object, may be released in atmosphere. The total activity of the dust falling out will be about 1.3 MCi, that can lead to more powerful contaminated of the south part of Belarus. Despite the hypothetical character of the scripts, the probability of their realisation at long operation of object will increase. Thus, the transformation of object 'UKRYTIE' to a safe system is an urgent problem. 1 ref., 3 figs

  16. Models of operator actions for avoiding the risk of deep vacuum in the confinement in case of a 200 mm LOCA on units 3 and 4 of NPP Kozloduy with reactors WWER-440/V230

    International Nuclear Information System (INIS)

    The authors present a set of models of operator actions for avoiding the risk of deep vacuum in the Confinement in case of a 200 mm LOCA on WWER-440/V230. The models are based on the plant operating experience. The actions performance and efficiency are analysed with representative CONTAIN calculations. The results form the basis for development and validation of Emergency Operating Procedures for LB LOCA accidents at units 3 and 4 of NPP Kozloduy. (author)

  17. Safety analysis of NPP

    International Nuclear Information System (INIS)

    This paper presents a short review of the parallel safety analysis of the various types of NPP. The NPP with PWR, WWER, BWR and HWR type reactors are mentioned. Technical, economic, location and ecology aspects of the safety of the NPP have been analysed. (author)

  18. COG CANDU outage optimization project at Wolsong, Qinshan, Cernavoda, Point Lepreau, Darlington and Pickering

    Energy Technology Data Exchange (ETDEWEB)

    McWilliams, L. [CANDU Owners Group, Toronto, Ontario (Canada)

    2011-07-01

    This COG initiated project objective is to reduce the timeline CANDU power plants are shutdown for planned maintenance outages through knowledge sharing, benchmarking and completion of a Gap Analysis. The following CANDU Nuclear Power Stations/Facilities formed a partnership to achieve the objective: Korean Hydro and Nuclear Power Company (Wolsong), Qinshan, Societatea Nationala 'Nuclearelectrica' (Cernavoda), New Brunswick Power Nuclear (Point Lepreau), Candu Energy Inc. (formerly AECL) and Ontario Power Generation Inc. (Darlington and Pickering). Project participants selected ten focus areas to evaluate and optimize. Benchmarking studies were conducted at each utility. A Gap Analysis was performed between the stations and site specific recommendations have been made considering: Critical path improvement opportunities (Unit Shutdown, RBLRT and Unit Start up); Major work program improvement opportunities (Turbine/Generator, Electrical Maintenance, MOT, SST and the Valve Program); Recommended modifications to reduce outage durations; and, Process Improvements (standardized clearance process). A final report has been issued to each station identifying: Gap Analysis Comparison results; Best Practices for each area studied; Site specific improvement opportunities; Most Effective Process for Outage Preparation; Most Effective Outage Execution Practices; and, Contingency Plan Preparation. Results were discussed during the presentation.

  19. Nuclear power plant life management: strategy for long term operation of the Beznau NPP unit 1 and 2

    International Nuclear Information System (INIS)

    The strategy for attaining long-term operation (LTO) of the Beznau nuclear power plants (NPPs) (2 Units) is given. The requirements, technical evaluations for LTO, in addition to considerations for fuel, radwaste disposal, staff and materials management and economic factors, are described. It is shown that, thanks to optimum management strategies, including backfitting and operational improvements, there are no technical reasons to prevent LTO. (author)

  20. Priority rankings of the system modifications to reduce core damage frequency of Wolsong NPP units 2/3/4

    International Nuclear Information System (INIS)

    The analysis for priority rankings of the recommendations to reduce the total core damage frequency (CDF) of Wolsong nuclear power plant units 2/3/4 was performed in this paper. In order to derive the recommendations, the sensitivity analysis of CDF on which major contributors effect was performed based on the accident quantification results during Level 1 probabilistic safety assessments (PSA). Priorities were ranked in the way that compares the CDF reduction rate with the efforts required to implement those recommendations using risk matrix

  1. The supply model of the IandC system modernization at VVER 1000 units of the NPP Temelin

    International Nuclear Information System (INIS)

    The history of the instrumentation and control system of the Temelin nuclear power plant is briefly mentioned. An upgrading of this system was initiated, aimed at enhancement of nuclear safety and at increasing the economical effectiveness of electricity production. The final supplier of the new system is SKODA PRAHA, the Westinghouse Electric Co. being the sub-supplier. By modernization of the IandC system, conditions have been created for an up-to-date WWER-1000 type unit which copes with the current requirements on nuclear safety and operating economy. (A.K.)

  2. Software development for simplified performance tests and weekly performance check in Younggwang NPP Unit 3 and 4

    International Nuclear Information System (INIS)

    This paper covers the current status of turbine cycle performance test in nuclear power plants and the software development which can solve some shortcomings related to performance tests. The software developed is for simplified performance tests and weekly performance checks in Yonggwang nuclear power plant unit 3 and 4. This software includes the requirements from the efficiency division for the consistency with actual performance analysis work and the usability of the collected performance test data. From the working survey, we identify the difference between the embedded performance analysis modules and the actual performance analysis work. This software helps operation or maintenance personnel to reduce work load, to support the trend analysis of essential parameters in a turbine cycle, and to utilize the correction curves for the decision-making in their work

  3. Safety enhancement at Beznau NPP

    International Nuclear Information System (INIS)

    The two units of the Beznau Nuclear Power Plant, Switzerland, are presented, and their safety related progress is evaluated. The largest safety enhancement has been the addition of a completely self-contained emergency system. Safety enhancements through backfitting measures in older nuclear power plants, however, have distinctive disadvantages compared to more modern plants. At Beznau NPP, safety has always priority over economics. (N.T.)

  4. Item 01: Peculiarities during installation of forced filtered venting system, units 3 and 4 of Kozloduy NPP

    International Nuclear Information System (INIS)

    The Forced Filtered Venting System (FFV) is designated to minimize the uncontrolled and unfiltered release of activity to the environment due to untightness of the confinement in case of a severe accident. In this paper the flow diagram of FFV, Units 3 and 4 is shown and the main components of the system which are installed in RB, in Rooms A 031/2, A032/3, A031/4, at elevation 2.10 m are described. Calculation models of the pipelines of FFV were developed based on the requirements to the design and the input data, which were collected and analyzed. The graphic part of the model is presented at calculation schemes. The pipelines are checked according to the requirements of the ASME Code and the equations for calculation of the connected pipelines are stipulated in ASME NC-3650. The enclosed photos illustrate the most relevant positions of the modifications. In conclusion the positive aspects of the mounting experience for this unique installation are analyzed and the weak points are stated aiming at the improvement of the quality of preparation, organization and complete performance for similar facilities

  5. Pilot Operation of Ex-core Neutron Sensors of Divers Shutdown System (DSS) Unit 2 Ignalina NPP

    International Nuclear Information System (INIS)

    The Ignalina Safety Assessment, which was completed in December 1996, recommended the installation of a diverse shutdown system on the 2nd unit at Ignalina. During the PPR-2004 in the DSS project are created two independent shutdown systems by separating the absorber rods into two independent groups as follows: 1. One system (designated AZ) consists of the existing 24 BAZ rods and 49 AZ/BSM rods that together are used for reliable reactor shutdown (including Control and Protection System (CPS) circuit voiding accident). This system performs the emergency protection function. 2. The other system (designated BSM) comprises the remaining absorber rods and the 49 AZ/BSM rods. Thus 49 AZ/BSM rods are actuated from AZ initiating equipment as well as from BSM initiating equipment. The BSM system performs the normal reactor shutdown function and is able to ensure long-term maintenance of the reactor in the sub-critical state. Along with implementation of DSS was modernized existing Emergency Process Protection System, which was divided into two independent Sets of initiating equipment. The DSS is independent and diverse initiating equipment from the existing 1st Set equipment; with each set having its own independent in-core and ex-core sensors for measurement of neutron flux and process parameters. The 2nd Set of initiating equipment for measuring ex-core neutron flux, was modernized with new design of 4 Ex-Core detectors each have a single low level neutron flux detector and two high range neutron detectors. They are comprising: 1. A fission chamber which operates in pulse mode to cover the low flux levels. 2. A compensated ionisation chamber in current mode to operate at high flux level. This detector is doubled to give a measurement of the axial deviation. Two detectors are enough to produce the axial power deviation. The results of testing and analysis of pilot operation of ex-core neutron sensors of DSS will be shown on the Report. (author)

  6. Replacement of shutdown cooling system and repair of reactor pressure vessel nozzle welds at NPP Forsmark unit 1 and unit 2

    International Nuclear Information System (INIS)

    The Forsmark Nuclear Power Plant is located about 150 km north of Stockholm. The plant consists of three units with boiling water reactors. Unit 1 and Unit 2 were put into operation in 1981 and 1982, respectively. Both of these units are identical each having a capacity of 970 MW. Unit 3 was completed in 1985 and has a capacity of 1160 MW. In November 1998 Babcock Noell Nuclear was awarded the contract to replace the pipe-work of the two-sectioned Shutdown Cooling System 321 from the nozzles at the reactor pressure vessel to 10 meters outside the containment. Moreover, the inner and outer isolation valves including the penetrations had to be replaced. Finally, the repair of the RPV (reactor pressure vessel) connecting welds of the System 415 (Feed Water) and System 323 (Emergency Cooling) was to be performed. The work was carried out by a Babcock Noell Nuclear team integrating Swedish companies during the outages May/June 2000 in Forsmark 2 and August/September 2000 in Forsmark 1. In the Forsmark Nuclear Power Plant, Units 1 and 2, 19 RPV nozzle connections were improved successfully. All relevant start-up deadlines could be kept. All new tools and manipulators met the stringent project requirements. The mockup qualification of the equipment and the special personnel training performed in advance proved that such challenging work can be managed despite limited preparation time and planned effectively in order to recognize and avoid possible risks. (authors)

  7. Role and contribution of AREVA NP GmbH and Siemens for completion of Belene NPP

    International Nuclear Information System (INIS)

    The content of the presentation includes: 1.Experience of AREVA NP / Siemens - participation in modernization and new building of NPP with VVER-1000: modernization of NPP Kozloduy Units 5 and 6 and contribution for NPP Tianwan Units 1 and 2; 2. AREVA NP / Siemens Contribution for Belene NPP: electrical systems; safety I and C; operational I and C; Heating-Ventilation-Air conditioning (HVAC); Hydrogen recombination; 3. Joint commitment for Belene

  8. NPP life management (abstracts)

    International Nuclear Information System (INIS)

    Abstracts of the papers presented at the International conference of the Ukrainian Nuclear Society 'NPP Life Management'. The following problems are considered: modernization of the NPP; NPP life management; waste and spent nuclear fuel management; decommissioning issues; control systems (including radiation and ecological control systems); information and control systems; legal and regulatory framework. State nuclear regulatory control; PR in nuclear power; training of personnel; economics of nuclear power engineering

  9. Bilibino NPP: Operation experience and design lifetime extension

    International Nuclear Information System (INIS)

    The Bilibino NPP (BiNPP) has been operated since early 1974 near the town of Bilibino in Chukotka. A high effectiveness of the nuclear energy sources use under the rigorous conditions of the Russian Federation's North- East region has been demonstrated. BiNPP was designed as nuclear co-generation plant. Some specific features of the area where the BiNPP is sited have necessitated several original engineering solutions in the reactor plant development and in the design of the NPP. Their correctness has been confirmed by the operating experience. BiNPP consists of four power units of the same type. The BiNPP's installed capacity amounts to 48 MW, with simultaneous heat production of 78 MW. In the period when the Russian economy was stable (up to 1991), the plant capacity factor amounted to 85%, with that of operating availability of 90-92%. The BiNPP's economic parameters were considerably superior vs. those of local organic fuel fired power sources. This advantage appears to increase to date due to significant rise of prices for organic fuel brought to the area. The analysis of accidents with normal operation of safety systems and with their failures has revealed features of rather high inherent self-protection of the reactor. The reactors' failure-free operation ensures the high reliability of BiNPP as power source under extreme conditions of the Far North-East. The BiNPP 1st unit's design lifetime of 30 years is to end in January of 2004, and that of the 4th unit - in December 2006. The question of extending the operation lifetime of Bilibino NPP beyond the design limit was raised because the project of the BiNPP-2 (second construction stage) developed in 1992 proved not to be feasible due to the high construction cost. (author)

  10. Changing NPP consumption patterns in the Holocene: from Megafauna "liberated" NPP to "ecological bankruptcy"

    Science.gov (United States)

    Doughty, C.

    2015-12-01

    There have been vast changes in how net primary production (NPP) is consumed by humans and animals during the Holocene beginning with a potential increase in availability following the Pleistocene megafauna extinctions. This was followed by the development of agriculture which began to gradually restrict availability of NPP for wild animals. Finally, humans entered the industrial era using non-plant based energies to power societies. Here I ask the following questions about these three energy transitions: 1. How much NPP energy may have become available following the megafauna extinctions? 2. When did humans, through agriculture and domestic animals, consume more NPP than wild mammals in each country? 3. When did humans and wild mammals use more energy than was available in total NPP in each country? To answer this last question I calculate NPP consumed by wild animals, crops, livestock, and energy use (all converted to units of MJ) and compare this with the total potential NPP (also in MJ) for each country. We develop the term "ecological bankruptcy" to refer to the level of consumption where not all energy needs can be met by the country's NPP. Currently, 82 countries and a net population of 5.4 billion are in the state of ecologically bankruptcy, crossing this threshold at various times over the past 40 years. By contrast, only 52 countries with a net population of 1.2 billion remain ecologically solvent. Overall, the Holocene has seen remarkable changes in consumption patterns of NPP, passing through three distinct phases. Humans began in a world where there was 1.6-4.1% unclaimed NPP to consume. From 1700-1850, humans began to consume more than wild animals (globally averaged). At present, >82% of people live in countries where not even all available plant matter could satisfy our energy demands.

  11. Akkuyu NPP – the first Turkish NPP. The new history of the project

    International Nuclear Information System (INIS)

    An overview is given to the Turkish energy sector and nuclear power plans. The project for the construction of the first NPP in Turkey is presented. The general parameters of the Project are: CAPEX: $ 20 bln; Project design: NPP-2006; (VVER- 1200); Number of units: 4; Total capacity: 4 800 MW; Construction period: 2014 – 2023; PPA period; 15 years, fixed price terms. An account of the activities during 2011, the Worley Parsons participation are presented and a tentative project schedule is given

  12. Integrated ageing management of Atucha NPP

    Energy Technology Data Exchange (ETDEWEB)

    Ranalli, Juan M.; Marchena, Martin H.; Zorrilla, Jorge R.; Antonaccio, Elvio E.; Brenna, Pablo; Yllanez, Daniela; Cruz, Gerardo Vera de la; Luraschi, Carlos, E-mail: ranalli@cnea.gov.ar [Gerencia Coordinacion Proyectos CNEA-NASA, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Sabransky, Mario, E-mail: msabransky@na-sa.com.ar [Departamento Gestion de Envejecimiento, Central Nuclear Atucha I-II Nucleoelectrica Argentina S.A., Provincia de Buenos Aires (Argentina)

    2013-07-01

    Atucha NPP is a two PHWR unit site located in Lima, Province of Buenos Aires, 120 km north of Buenos Aires, Argentina. Until recent, the site was split in Atucha I NPP, a 350 MW pressure vessel heavy water reactor in operation since 1974; and Atucha II, a similar design reactor, twice as big as Atucha I finishing a delayed construction. With the start-up of Atucha II and aiming to integrate the management of the plants, the Utility (Nucleolectrica Argentina Sociedad Anonima - NASA) has reorganized its operation units. Within this reorganization, an Ageing Management Department has been created to cope with all ageing issues of both Atucha I and II units. The Atomic Energy Commission of Argentina (Comision Nacional de Energia Atomica - CNEA) is a state-owned R and D organization that; among other functions such as designing and building research reactors, developing uranium mining and supplying radioisotopes to the medical market; is in charge of providing support and technological update to all Argentinean NPPs. The Ageing Management Department of Atucha NPP and the Ageing Management Division of CNEA has formed a joint working group in order to set up an Integrated Ageing Management Program for Atucha NPP following IAEA guidelines. In the present work a summary of the activities, documental structure and first outputs of the Integrated Ageing Management Program of Atucha NPP is presented. (author)

  13. Integrated ageing management of Atucha NPP

    International Nuclear Information System (INIS)

    Atucha NPP is a two PHWR unit site located in Lima, Province of Buenos Aires, 120 km north of Buenos Aires, Argentina. Until recent, the site was split in Atucha I NPP, a 350 MW pressure vessel heavy water reactor in operation since 1974; and Atucha II, a similar design reactor, twice as big as Atucha I finishing a delayed construction. With the start-up of Atucha II and aiming to integrate the management of the plants, the Utility (Nucleolectrica Argentina Sociedad Anonima - NASA) has reorganized its operation units. Within this reorganization, an Ageing Management Department has been created to cope with all ageing issues of both Atucha I and II units. The Atomic Energy Commission of Argentina (Comision Nacional de Energia Atomica - CNEA) is a state-owned R and D organization that; among other functions such as designing and building research reactors, developing uranium mining and supplying radioisotopes to the medical market; is in charge of providing support and technological update to all Argentinean NPPs. The Ageing Management Department of Atucha NPP and the Ageing Management Division of CNEA has formed a joint working group in order to set up an Integrated Ageing Management Program for Atucha NPP following IAEA guidelines. In the present work a summary of the activities, documental structure and first outputs of the Integrated Ageing Management Program of Atucha NPP is presented. (author)

  14. Safety upgrading program in NPP Mochovce

    International Nuclear Information System (INIS)

    EMO interest is to operate only nuclear power plants with high standards of nuclear safety. This aim EMO declare on preparation completion and commissioning of Mochovce Nuclear Power Plant. Wide co-operation of our company with International Atomic Energy Agency and west European Inst.ions and companies has been started with aim to fulfil the nuclear safety requirements for Mochovce NPP. Set of 87 safety measures was implemented at Mochovce Unit 1 and is under construction at Unit 2. Mochovce NPP approach to safety upgrading implementation is showed on chosen measures. This presentation is focused on the issues category III.(author)

  15. Ignalina NPP pre-decommissioning projects

    International Nuclear Information System (INIS)

    Description of the main projects for the preparation to the decommissioning of unit 1 of Ignalina NPP is presented. These projects are to be financed by international donors as one of the conditions to shutdown unit before the year 2005. These projects were presented during Donors conference held in 21-22 June 2000 in Vilnius. The conference was organized jointly by Lithuanian Government and European Commission. Projects are devoted to the construction of radioactive waste management facilities and improvement of existing waste management practices at Ignalina NPP as well for the general management of decommissioning process preparation of necessary documentation

  16. Application of collimated detector emergency response in engine room of power unit 4 of NPP prior to uranium sorption from pulps

    International Nuclear Information System (INIS)

    Methods providing for remote measurement of surface density distribution of ionizing radiation source activity, for plotting maps of radiation activity surface distribution, for calculating exposure dose maps or exposure doses at any prescribed point, for evaluating the contribution of various sources to exposure doses, for forcasting variations in dependence on planned or accidental activity change at any place of the closed building are considered. The advantage of the methods consists in that all calculations, various version modeling, choice of optimal ways are carried out without personnel irradiation. The methodology mentioned above was aplied in the course of elimination of accident consequences at the Chernobyl NPP

  17. Fuel reliability of Bohunice NPP

    International Nuclear Information System (INIS)

    Paper summarizes experience from last 15 years of operation at NPP Jaslovske Bohunice. During this period, leaking fuel assemblies have had been identified by in-core sipping method and verified by vendor specified canister sipping method. Methodology of operational and outage fuel integrity monitoring is described. Full survey of identified leaking assemblies is given. Fuel failure rates are calculated separately for V-1 (V-230 type) and V-2 (V-213 type) units. Systematic difference - significantly lower fuel failure rate at V-213 units exists for all period investigated. Analysis of potential fuel failure reasons and all related measures (planned and already implemented) are presented. Design, operation and fabrication features have been analyzed with the aim to identify dominant factors contributing to fuel failure. No unambiguous reasons have been found so far. It is believed that there is a superposition of several factors and differences causing higher failure rate at V-230 type units. (author)

  18. Safety Improvement at the Ignalina NPP (SIP-2)

    International Nuclear Information System (INIS)

    Implementation of SIP-2 began in 1997. The programme envisages measures through introduction of which conclusions concerning safety improvement given in SAR-1 are implemented. Implementation of SIP-2 measures is a precondition for the validity of the operating licence for Unit 1 at the Ignalina NPP, and for issuing the operating licence for Unit 2, to whose licensing the Ignalina NPP and VATESI are getting ready. Results of the Programme are described

  19. Project No. 10 - Partial restoration of Ignalina NPP territory

    International Nuclear Information System (INIS)

    At present Ignalina NPP territory makes a total of 2544 ha of land. Due to termination of construction activity development and due to the decision taken to shutdown unit 1 the need in such a territory fell off. For normal and safe operation of Ignalina NPP 1440 ha is enough, including 1237 ha for of Ignalina NPP administrative area and 203 ha for auxiliary objects. Ignalina NPP will have to rearrange territory, forestry that was damaged during the construction activities of the plant and to restore the damaged farmlands and to pass the rearranged forestry that belonged to the Ignalina NPP to the Ministry of Forestry. The total estimated cost of the project is about 1.042 M EURO

  20. The Tokai NPP decommissioning technique

    International Nuclear Information System (INIS)

    Tokai power station was closed down in March 1998 and started decommissioning from December 2001 as a pioneer of NPP decommissioning. This article presented current state of Tokai NPP decommissioning technique. As the second stage of decommissioning works, removal works of steam raising unit (four units of heat exchangers) were started from 2006 by jacking down method with decommissioning data accumulated. Each heat exchanger was divided into top head, seven 'tears' of shell and bottom head. Each 'tear' was out and separated into a cylinder, and then divided into two by remote-operated cutting equipment with manipulators for gas cutting and motor disk cutting under monitoring works by fixed and mobile cameras. Divided 'tear' was further cut into center baffle plate, heat transfer tubes and fine pieces of shell. Cutting works would produce radioactive fine particles, which were filtered by temporary ventilation equipment with exhaust fan and filters. Appropriate works using existing technique combined and their rationalization were important at this stage. (T. Tanaka)

  1. Regulatory approach to NPP ageing in Romania

    International Nuclear Information System (INIS)

    In this paper the Romanian requirements for ageing management of systems and components important to safety of Cernavoda nuclear power plant (one Candu type reactor, heavy water moderated power reactor) are presented

  2. NPP electrical price and tariff in the world

    International Nuclear Information System (INIS)

    Construction of a Nuclear Power Plant (NPP) is always become a controversial issue. Nuclear utility and other party which support the NPP present a calculation of NPP electricity cost too optimistic. However for utility and other party that contra to nuclear present a calculation of NPP electricity cost too pessimistic. This study present to reduce the controversy of nuclear cost. In this study, capital cost (Engineering Procurement Construction, EPC) was taken from Asian, America and Europe, operating and maintenance cost uses experience data of PLN, and nuclear fuel cost uses data year of 2008 with high price, low price and average price scenario. The methodological tools used to compare electricity generation cost was LEGECOST, a program developed by IAEA (International Atomic Energy Agency), while for electricity tariff- price calculation using a program developed by PLN research and development center. With the discount rate 10%, the result shows that the cheapest electricity generation cost of NPP is less than 40 mills/kWh, and average electricity tariff was 55 mills/kWh. In the Europe countries the electricity tariff more expensive than NPP in Asia. However generating cost and electricity tariff of NPP in United Stated of America (USA) less competitive because investment cost more expensive. Generating cost and electricity tariff was different at each country depend on salary, labor wage, materials price, construction specification, regulation related to NPP and environment aspect. (author)

  3. Modern Russian steam turbines and condensers up to 1500 MW capacity for the NPP

    International Nuclear Information System (INIS)

    The OJSC Power Machines experience in turbine for Thermal and Nuclear Power Plants production and the basic concept concerning the NPP turbines design are discussed. Turbine design features and measures to enhance reliability and efficiency of Power Machines turbines rated 1000 MW for NPP are listed. The conception of modernization of condensers for NPP and the experience of operating LMZ turbines for NPP are discussed. The OJSC Power Machines participation and research in development of the perspective turbines rated from 800 MW to 1600 MW for NPP units are also presented

  4. Gamma irradiation tests of concrete material recommended for storage casks of spent nuclear fuel arising from Cernavoda NPP

    International Nuclear Information System (INIS)

    Considerable effort is being devoted in the Romania's Nuclear Spent Fuel and Waste Management R and D Program to develop engineered barriers for the containment of nuclear fuel waste under conditions of deep geological disposal. Engineering practice suggests that the concrete should fulfill the requirements of long term physical stability and resistance to radiation damage. With an appropriate system of metal reinforcement, it should be possible to obtain the tensile and impact strength required avoiding the risk of mechanical damage during handling and emplacement. In accordance with the concept developed by SITON-Bucharest, presently, the dry storage of spent nuclear fuel is thought by two choices: the alternative of dry storage type MMB3 and the alternative of dry storage type TRANSTOR. By using ORIGEN and PELSHIE computer codes, we evaluated the absorbed gamma radiation dose absorbed by the concrete walls of the storage vault both in MMB3 and in TRANSTOR designing choice.The irradiation tests were performed at the Gamma Irradiation Facility from the Institute for Nuclear Research. (authors)

  5. Gamma irradiation tests of concrete material recommended for storage casks of spent nuclear fuel arising from Cernavoda NPP

    International Nuclear Information System (INIS)

    Considerable effort is being devoted to the Romania's Nuclear Spent Fuel and Waste Management R and D Program to develop engineered barriers for the containment of nuclear fuel waste under conditions of deep geological disposal. Engineering practice suggests that the concrete should fulfil the requirements of long term physical stability and resistance to radiation. With an appropriate system of metal reinforcement, it should be possible to obtain the tensile and impact strength required, avoiding the risk of mechanical damage during handling and emplacement. In accordance with the concept developed by CITON-Bucharest, presently, the dry storage of spent nuclear fuel is thought by two choices: - The alternative of dry storage type MMB3; - The alternative of dry storage type TRANSTOR. By using ORIGEN and PELSHIE computer codes, we evaluated the gamma radiation dose absorbed by the concrete walls of the storage vault both in MMB3 and in TRANSTOR designing variants. The irradiation tests were performed at the Gamma Irradiation Facility of the Institute for Nuclear Research. (authors)

  6. Evaluation of equivalent dynamic soil properties from experimental and analytical studies of foundation model at the site of NPP Cernavoda

    International Nuclear Information System (INIS)

    The seismic response of a building of the nuclear power plant, is determined, to a great extent, by the foundation soil parameters (the dependence of the shear mode and the internal damping with shear strain as result of the loads generated by seismic wave). These dynamic soil parameters values may determine (or not) the resonating of the building with the seismic excitation typical for that site and may or may not damp the seismic energy transferred to the building. Generally the determination of the soil dynamic parameters is made by measurements, in situ, of the 'p' and 's' propagation wave velocities for very low strain cases of the foundation soil as well as by lab testing with resonant column. In order to determine the shear models variation and the internal damping variation with the strain condition, upon the undersigned proposal, a study on a cylindrical model built in a cavity made in limestone and founded on clay layer was elaborated. The model was subjected to shocks generated by land blasting and to pulling by a tractor associated with the sudden release of the load and the module was left to oscillate freely. The model was subjected also to forced oscillations generated by a vibrator installed on top of the model. In order to determine the dynamic parameters of limestone layer, the behavior of the model after its embedding into limestone layer by cyclopean concrete poring was analyzed. Following to the analysis, the variation of shear mode and soil damping, for clay layer were determined. For limestone layer it was determined that the modification of parameter reduction is maximum 15 %. (authors)

  7. Foreign NPP decommissioning

    International Nuclear Information System (INIS)

    Different versions of NPP decommisioning, which worked out their life are considered. Dismantling work technology as well as devices for cutting and decontamination of equipment and concrete structures are described. Data on the quantity of shutdown and dismantled NPPs are given. It is noted that to perform successfully dismantling works it is necessary to: choose NPP decommisioning version; calculate radioactivity level; substantiate necessity of decontamination; develop the plan of removal of radioactive equipment; radioactive concrete and structures; contaminated systems; transport and bury solid, liquid and gaseous radioactive and chemical wastes; evaluate the accepted solutions of dismantling from the point of view of the effect on environment; determine costs. It is shown that optimal period of complete or partial dismantling after the NPP decommisioning is 15 years. NPPs dismantling expenditures can reach 10-15% of expenditures for their construction

  8. KEPIC application on Korean NPP

    International Nuclear Information System (INIS)

    In the management of nuclear power plant, the security of safety is most important and the such a safety security is closely related to the governing code requirements for nuclear facility. In the first stage of NPP construction in Korea, there was no independent Korean codes for the nuclear facility, accordingly different kind of foreign codes were applied. From the later of 1980, KHNP leads the development of KEPIC (Korea Electric Power Industry Code). The development had been being performed in the three step and finished in the end of Dec. 2000. After that, the KEPIC developed had been selectively applied for the UI-Chin 5 and 6 units construction and it is now expected that the application of KEPIC will be markably expended in the Shin-Kori 1 and 2 and Shin Wol-Sung 1 and 2 units scheduled. Thereby here I introduce the status of development and application of the KEPIC for information of persons interested

  9. Qualified operator training in the simulated control room environment

    International Nuclear Information System (INIS)

    Full text: Mainly designed for the training of the Cernavoda NPP Unit 2 operators, the virtual simulated environment allows the training of the already qualified operators for Cernavoda NPP Unit 1, adding to the already trained knowledge, the differences which has occurred in the Unit 2 design. Using state-of-the-art computers and displays and qualified software, the virtual simulated panels could offer a viable alternative to classic hardware-based training. This approach allows quick training of the new procedures required by the new configuration of the re-designed operator panels in the main control room of Cernavoda NPP Unit 2. (authors)

  10. EMAS at Doel NPP

    International Nuclear Information System (INIS)

    In October 1995, Doel NPP of Electrabel, Belgium opted to seek registration under the EC Eco-management and Audit Scheme (EMAS). A comprehensive environmental management system (EMS) has been introduced and implemented, encompassing all four PWRs and the supporting departments. A critical step was to seek certification from an accredited environmental auditing body against the International Standard ISO 14001. This provided the foundation for the publicly available environmental statement required by EMAS. The complications of achieving EMAS at a time when national and international standards were being re-formulated were successfully overcome and Doel NPP passed its EMAS audit in June 1997. (author)

  11. Nuclear fuel cycles of WWER-1000 at Kozloduy NPP: a program for transition to advanced fuel

    International Nuclear Information System (INIS)

    A systematical approach for WWER nuclear fuel utilization improvement is applied at the Kozloduy NPP while observing safety requirements. The fuel assemblies utilization for 4 years, higher burnup and reducing of high-activity radioactive waste will be achieved by realization of Activities program for transition of Units 5 and 6 of Kozloduy NPP to operating with Alternative Fuel Assemblies (AFA). The specified results from advanced fuel introduction also will improve the economic indices of Units 5 and 6 operation at Kozloduy NPP

  12. Safety culture at Ignalina NPP

    International Nuclear Information System (INIS)

    In accordance with Article 27 of the Law on Nuclear Energy of the Republic of Lithuania, the organization operating the nuclear power facility must ensure adequate safety culture. Safety culture comprises specific features and characteristics of the organisation's activities as well as human behavior ensuring that the issues of a nuclear power facility's safety will be given attention consistent with their importance. To ensure adequate level of safety culture, Ignalina NPP has been following IAEA recommendations. The INPP draws up and implements plans of safety culture assurance every year. The Director General meets with IAEA personnel on a regular basis and discusses issues that hold most interest for them. In 2005, INPP management reviewed and approved on September 30 the new policy of safety and quality assurance. The document differs from the policy approved in 1995 in that priorities are set for INPP decommissioning. It is emphasized that INPP Unit 2 operation must be terminated in the most efficient and safest manner, with adequate social security of the personnel assured and effective management system of the facility maintained. The work commenced in 2004 at the Ignalina NPP on identification and application of safety culture indicators was continued in 2005. (author)

  13. NPP Krsko decommissioning concept

    International Nuclear Information System (INIS)

    At the end of the operational lifetime of a nuclear power plant (NPP) it is necessary to take measures for the decommissioning as stated in different international regulations and also in the national Slovenian law. Based on these requirements Slovenian authorities requested the development of a site specific decommissioning plan for the NPP Krsko. In September 1995, the Nuklearna Elektrarna Krsko (NEK) developed a site specific scope and content for a decommissioning plan including the assumptions for determination of the decommissioning costs. The NEK Decommissioning Plan contains sufficient information to fulfill the decommissioning requirements identified by NRC, IAEA and OECD - NEA regulations. In this paper the activities and results of development of NEK Decommissioning Plan consisting of the development of three decommissioning strategies for the NPP Krsko and selection of the most suitable strategy based on site specific, social, technical, radiological and economic aspects, cost estimates for the strategies including the costs for construction of final disposal facilities for fuel/high level waste (fuel/HLW) and low/intermediate level waste (LLW/ILW) and scheduling of all activities necessary for the decommissioning of the NPP Krsko are presented. (author)

  14. NPP Krsko decommissioning concept

    International Nuclear Information System (INIS)

    At the end of the operational lifetime of a nuclear power plant (NPP) it is necessary to take measures for the decommissioning as stated in different international regulations and also in the national Slovenian law. Based on these requirements Slovenian authorities requested the development of a site specific decommissioning plan for the NPP KRSKO. In September 1995, the Nuklearna Elektrarna Krsko (NEK) developed a site specific scope and content for decommissioning plan including the assumptions for determination of the decommissioning costs. The NEK Decommissioning Plan contains sufficient information to fulfill decommissioning requirements identified by NRC, IAEA and OECD - NEA regulations. In this paper the activities and the results of development of NEK Decommissioning Plan consisting of the development of three decommissioning strategies for the NPP Krsko and selection of the most suitable strategy based on site specific, social, technical, radiological and economical aspects, cost estimates for the strategies including the costs for construction of final disposal facilities for fuel/high level waste (fuel/HLW) and low/intermediate level waste (LLW/ILW) and scheduling all activities necessary for the decommissioning of the NPP KRSKO are presented. (author)

  15. Design safety improvements of Kozloduy NPP

    International Nuclear Information System (INIS)

    Design safety improvements of Kozloduy NPP, discussed in detail, are concerned with: primary circuit integrity; reactor pressure vessel integrity; primary coolant piping integrity; primary coolant overpressure protection; leak before break status; design basis accidents and transients; severe accident analysis; improvements of safety and support systems; containment/confinement leak tightness and strength; seismic safety improvements; WWER-1000 control rod insertion; upgrading and modernization of Units 5 and 6; Year 2000 problem

  16. Design floor response spectra for Kozloduy NPP

    International Nuclear Information System (INIS)

    This presentation contains a detailed review of the design response spectrum for the floor of Kozloduy NPP Units 5 and 6. Design model was developed according to the plan to build this type od nuclear power plants in different regions. Calculations were done with a set of accelerograms, which includes artificial and already known recordings of earthquakes. Envelope response spectrum of the set of accelerograms is presented

  17. Dukovany NPP fuel cycle benchmark definition

    International Nuclear Information System (INIS)

    The new benchmark based on Dukovany NPP Unit-2 history is defined. The main goal of this benchmark is to compare results obtained by different codes used for neutron-physics calculation in organisations which are interested in this task. All needed are described in this paper or there are given references, where it is possible to obtain this information. Input data are presented in tables, requested output data format for automatic processing is described (Authors)

  18. Baltic NPP Project specifics and current status

    International Nuclear Information System (INIS)

    Project overview: 2 x 1194 MW Units (AES-2006 series); Location in Kaliningrad region of the; Russian Federation; Operation dates: Unit 1 – Oct 2016; Unit 2 – Apr 2018; Site preparatory works ongoing. This is first NPP project in the Russian Federation providing opportunity for participation of foreign investors. Foreign investors may acquire up to 49% share. Cross-border transmission lines developed under separate project with participation of foreign investors. Conclusion: At the selected set of assumptions, the project is financially feasible in all scenarios

  19. Implementing safety improvement program (SIP-3) at Ignalina NPP

    International Nuclear Information System (INIS)

    It is stated in license validity conditions for Ignalina NPP Unit 2 operation that the operating organization is to implement on time safety improvement measures and to submit an implementation report to VATESI on a quarterly basis. It is stated in another condition of validity of operation license for Ignalina NPP Unit 2 that based on the results of SAR-2 and RSR-2, the organization operating the Ignalina NPP is to prepare and submit to VATESI for approval the new safety improvement at Ignalina NPP program SIP-3 by December 2004. The Ignalina NPP submitted the draft SIP-3 in December 2004, and on April 8, 2005, VATESI approved it. One hundred and fifteen SIP-3 measures are to be implemented at Ignalina NPP in 2005-2008; 80, 24, and 7 measures in 2005, 2006, and 2007-2008, respectively, whereas 4 measures are being implemented continuously. In 2005, items were being implemented of SIP-3 that had not been accomplished when implementing SIP-2 in 2004 and envisaged in VATESI requirements and statements of inspections. The recommendations of safety case for the single Unit 2 operational at Ignalina NPP, those of SAR and RSR for INPP Unit 2, the plan of measures of INPP Unit 1 decommissioning program, the recommendations of the International Physical Protection Advisory Service (IPPAS) mission, instructions of INPP police team of the State Border Guard Service, technical decisions by INPP, statements, plans of measures, safety upgrading modifications, etc. were also taken into consideration when producing SIP-3. Major SIP-3 measures for safety upgrading at INPP implemented and approved in 2005 are listed. (author)

  20. A historical survey of the Ignalina NPP

    International Nuclear Information System (INIS)

    Full text: When the boom of nuclear power industry began in the former Soviet Union, the idea of constructing the Ignalina NPP occurred to the circles in Moscow's central institutions at the turn of the 1970s. The nuclear power plant remained a facility under all-union jurisdiction supervised by the Ministries of Atomic Energy and Medium-Machine Building of the USSR from September 16, 1971, when the Central Committee of the Communist Party of the Soviet Union and the Council of Ministers of the Soviet Union adopted the resolution regarding the beginning of its construction, until Lithuania regained independence in 1990. Nuclear power is the basis of Lithuania's power industry. The Ignalina NPP is a product of the former Soviet Union. Two reactors of RBMK-1SOO type are operational at the Ignalina NPP. This is the most advanced and the most recent version of the RBMK reactor design series (only two reactors of this type have ever been built). The power plant was built as part of the Soviet Union's North-West Unified Power System rather than to meet Lithuania's needs. The first unit of Ignalina NPP was commissioned in late 1983, and the second one in August 1987. A total of four units with RBI/1K-1S00 reactors were to be built. However, due to political and safety motives the construction of the third unit was suspended as early as 1989. After Lithuania declared independence in 1990, the Ignalina NPP was still guarded by Soviet troops and KGB operatives, and remained under the jurisdiction of the Soviet Union until August 1991. Supervision was carried out by that country's regulatory authority, the State Nuclear Power Supervision Inspection (Gosatomnadzor). It was only after the political events of August 1991 in Moscow that the Ignalina NPP finally came under the authority of the Lithuanian Republic. It is now controlled administratively by the Lithuanian Ministry of Economy, and its supervision is carried out by the Lithuanian State Nuclear Power Safety Inspectorate

  1. Russian NPP I and C systems and NPP safety problems

    International Nuclear Information System (INIS)

    The long experience of nuclear power plant (NPP) operation both in Russia and over the world confirms that both power and economic characteristics as well as NPP safety depend on possibilities and specifications of instrumentation and control (I and C) systems. That is why the more serious attention is paid to the problems of improvement of I and C systems in all countries

  2. SAT for NPP personnel training in USA

    International Nuclear Information System (INIS)

    This discussion addressed the experience with the application of SAT at USA NPPs. In particular, the transition of NPP training processes, staff composition, and reporting structure from the TMI accident to present. As well, oversight and guidance activities of the INPO and more intensive inspection by the NRC began during this period. The average NPP training staff grew to 30-40 per unit, along with a change in reporting line from plant to corporate management. With the reduction of resources occurring in the late 1980s, overall training staff size decreased, the composition changed, and reporting line reverted to plant management. The overall lessons-learned for application of the SAT consisted of the need for simplification, management involvement, and exploitation of the technology

  3. 数字化核电厂全范围模拟机研制方案概述%The Development Scheme of Full Scope Simulator for DCS-based NPP Unit

    Institute of Scientific and Technical Information of China (English)

    陈春丽

    2014-01-01

    概述了核电厂全范围模拟机的性能和功能要求及最新应用,阐述了当今主流数字化控制核电厂全范围模拟机的总体研制方案,并着重针对数字化仪控系统的不同处理方式进行了性能和经济性的比较。最后介绍了方家山核电工程1、2号机组全范围模拟机的技术方案。%The paper summarizes the requirements for the Full Scope Simulator of current nuclear power plant , and the new application demands in V&V field as well .For DCS-based Nuclear Power Plant unit , the devel-opment scheme of its Full Scope Simulator is introduced , and different solutions to DCS implementation are compared .And the technical solution to the Full scope simulator of Fangjiashan NPP is described as an exam -ple.

  4. International benchmark for coupled codes and uncertainty analysis in modelling: switching-Off of one of the four operating main circulation pumps at nominal reactor power at NPP Kalinin unit 3

    International Nuclear Information System (INIS)

    The paper briefly describes the Specification of an international NEA/OECD benchmark based on measured plant data. During the commissioning tests for nominal power at NPP Kalinin Unit 3 a lot of measurements of neutron and thermo-hydraulic parameters have been carried out in the reactor pressure vessel, primary and the secondary circuits. One of the measured data sets for the transient 'Switching-off of one Main Circulation Pump (MCP) at nominal power' has been chosen to be applied for validation of coupled thermal-hydraulic and neutron-kinetic system codes and additionally for performing of uncertainty analyses as a part of the NEA/OECD Uncertainty Analysis in Modeling Benchmark. The benchmark is opened for all countries and institutions. The experimental data and the final specification with the cross section libraries will be provided to the participants from NEA/OECD only after official declaration of real participation in the benchmark and delivery of the simulated results of the transient for comparison. (Author)

  5. Novel solutions in the implementation of the system for visual indication of the safety parameters of units 5 and 6 of the Kozloduy NPP (SPDS)

    International Nuclear Information System (INIS)

    The project is part of the modernization of units 5 and 6 , and one of the last measures implemented . The approach includes modular software: applications for input from the units and calculations; relational database linking the input with application programs and describing the calculational algorithms; man-machine interface; system software and links; navigation and control software etc. The objective is to exclude any impact on the system Ovation; IPD system expandability to allow the implementation of computerized alarm and emergency procedures; System to be installed on the Full Scale Simulator-1000, verified and validated, by simulating the slow and fast transients

  6. The main steps of the Romanian nuclear power program development - Accumulated experience

    International Nuclear Information System (INIS)

    The paper presents a historical summary of the Romanian Nuclear Power Program development, providing details for the main criteria and principles the Program was based upon, the contracts signed with the foreign partners to implement it, and the national participation (site contractors, suppliers and design organizations). The effect of the equipment assimilation program on the NPP Cernavoda (5x700 MWe) and especially on Unit 1 schedule and performance is analyzed. Further on the impact of the transition from centralized to a market economy over the Romanian Nuclear Power Program development is analyzed, providing information's on its actual status and perspectives for the next 20 years. A description of the NPP Cernavoda Unit 1 actual progress and of the main steps performed by RENEL to get finance to complete NPP Cernavoda Unit 2 is included. Finally there is summarized the accumulated experience, and its feed back on RENEL strategy to complete NPP Cernavoda Unit 2. (author)

  7. IAEA recommendations on NPP safety

    International Nuclear Information System (INIS)

    Codes developed in IAEA on the basis of the NUSS program (Nuclear Safety Standards) concerning nuclear safety of thermal reactor NPPs and published in 1978 are considered. 5 main codes and manuals have been stated: 1. Governmental organization for the regulation of NPP; 2. Safety in NPP siting; 3. Design for safety of NPP; 4. Safety in NPP operation; 5. Quality assuarance for safety in Nuclear Power Plants. The Codes contain recommendations on providing safety of population and personnel as well as on environmental protection. They also contain criteria and proper measures corresponding to both operating conditions of NPP and possible emergency conditions. Some provisions in the Codes may be also used, for providing radiation safety and at the external fuel cycle plants

  8. Human Resources Training Requirement on NPP Operation and Maintenance

    International Nuclear Information System (INIS)

    This paper discussed the human resources requirement on Nuclear Power Plant (NPP) operation and maintenance (O&M) phase related with the training required for O&M personnel. In addition, this paper also briefly discussed the availability of training facilities domestically include with some suggestion to develop the training facilities intended for the near future time in Indonesia. This paper was developed under the assumptions that Indonesia will build twin unit of NPP with capacity 1000 MWe for each using the turnkey contract method. The total of NPP O&M personnel were predicted about 692 peoples which consists of 42 personnel located in the head quarter and the rest 650 people work at NPP site. Up until now, Indonesia had the experience on operating and maintaining the nonnuclear power plant and several research reactors namely Kartini Reactor Yogyakarta, Triga Mark II Reactor Bandung, and GA Siwabessy Reactor Serpong. Beside that, experience on operating and maintaining the NPP in other countries would act as one of the reference to Indonesia in formulating an appropriate strategy to develop NPP human resources particularly in O&M phases. Education and training development program could be done trough the cooperation with vendor candidates. (author)

  9. WWER-440 equipment and reactor system development during NPP operation

    International Nuclear Information System (INIS)

    In order to extend the service lifetime of the WWER-440 reactors in Russia the Program for Preparation of the 1st generation NPP Units for service lifetime extension has been adopted. In the Program the preparation and licensing procedures are presented. On the base of the Program several technical documents have been developed for the Novo Voronezh NPP unit 3. The measures for providing of an adequate safety level are based on the results from the performed probabilistic safety assessment. Working programs are developed also for the other 1st generation NPPs

  10. The performance shaping factors influence analysis on the human reliability for NPP operation

    International Nuclear Information System (INIS)

    The Human Reliability Analysis (HRA) is an important step in Probabilistic Safety Assessment (PSA) studies and offers an advisability for concrete improvement of the man - machine - organization interfaces, reliability and safety. The goals of this analysis are to obtain sufficient details in order to understand and document all-important factors that affect human performance. The purpose of this paper is to estimate the human errors probabilities in view of the negative or positive effect of the human performance shaping factors (PSFs) for the mitigation of the initiating events which could occur in Nuclear Power Plant (NPP). Using THERP and SPAR-H methods, an analysis model of PSFs influence on the human reliability is performed. This model is applied to more important activities, that are necessary to mitigate 'one steam generator tube failure' event at Cernavoda NPP. The results are joint human error probabilities (JHEP) values estimated for the following situations: without regarding to PSFs influence; with PSFs in specific conditions; with PSFs which could have only positive influence and with PSFs which could have only negative influence. In addition, PSFs with negative influence were identified and using the DOE method, the necessary activities for changing negative influence were assigned. (authors)

  11. Developing the stands for technological runs of thermal monitoring means for NPP

    International Nuclear Information System (INIS)

    The aim of the paper is to describe developing the stands of technological runs (TR) of the thermal monitoring means for NPP. The TR stand includes: heating units, power unit of heating units, control unit, protection unit, detection unit, set-point devices of temperature and protection. The block diagram of a TR stand is presented

  12. Kozloduy NPP - its 20 years operational experience

    International Nuclear Information System (INIS)

    The main technical and economic results of 20 year operation of the Kozloduy NPP are summarised. The total electricity produced amounts to more than 200 billions KWh. The energy produced by the plant accounts for more than 40% of the national electricity output since 1993. Details of electricity production in different years by all 6 units are given. The efficiency of units 1-4 (WWER-440) is 29-30% and of units 5-6 (WWER-1000) is 29-33%. The Unit 6 has best characteristics. Since 1989 a safety test is being carried out in cooperation with the IAEA. Units 1 and 2 have been reconstructed in order to enhance safety and reliability. 1 tab

  13. Demands on project management of comprehensive modernization projects in the electrical systems area. Example of modernization of electrical systems of Kozloduy NPP Unit 5 and 6

    International Nuclear Information System (INIS)

    In nuclear power plants, station supply with electric energy must be guaranteed any time. This applies in particular also during the implementation of complex electrical systems modernization projects. Highest demands on the project management, extensive experience and system knowledge are required. In the frame of the Modernization Program for the nuclear power plant Kozloduy unit 5 and 6 in Bulgaria Framatome ANP has approved its ability to implement a large scope of modernization measures during the refueling outages of the years 2003 to 2005. The Contract of the Modernization Program for the European Consortium Kozloduy (Framatome ANP, Atomenergoexport) was signed in July 1999 and became effective in June 2001. The project will be finished by May 2006, with the approval of the Updated Final Safety Analysis Report. The scope of hardware work has been implemented within 6 plant outages during the years 2002 to 2005. The focus of the Modernization Program is mainly oriented to nuclear safety aspects, with the aim of upgrading of the Units to a high safety level in compliance with international practice. A further section of the project is dedicated to upgrading of operational equipment. Framatome ANP personnel have shown that besides the technical challenges which had to be faced, also the intercultural and language barriers were successfully overcome. The good teamwork between the partners of the Consortium ECK, its Bulgarian subcontractors and with Kozloduy plant personnel has been an important success factor. (authors)

  14. Personnel overexposure while extracting leaky fuel assembly from the reactor core on 21.11.95 at Kursk NPP, Unit 4 (the Russian Federation)

    International Nuclear Information System (INIS)

    Brief description of the event: The unit was operating at nominal power. Based on Burst Can Detection System (BCDS) indications personnel observed increased activity of steam at the fuel channel (FC) outlet which indicated leaky fuel rods. Once the affected FC with depressurized fuel rods was identified, efforts were started to discharge the affected fuel assembly from the 47-45 FC. During fuel assembly discharge operation radiation monitoring system alarms went off periodically in the central (reactor) hall. Examination of the place of work performing revealed the following: one fragment of the fuel of 5 mm size was discovered on the receiving unit of the shipping cask with discharged fuel assembly and two fragments of 1.5-2.0 mm size were found on the fuel assembly plug. Fuel fragments were removed in accordance with established procedures. The checking of personal dosimeters of eight workers who took part in the work showed that two persons had increased external exposure doses exceeding the annual limit (58.3 and 56.7 mSv respectively). 2 figs

  15. Demands on project management of comprehensive modernization projects in the electrical systems area. Example of modernization of electrical systems of Kozloduy NPP Unit 5 and 6

    Energy Technology Data Exchange (ETDEWEB)

    Stinshoff, Helmut; Weber, Patrick [Framatome ANP GmbH, P.O. Box 3220, Freyeslebenstrasse 1, D-91050 Erlangen (Germany)

    2006-07-01

    In nuclear power plants, station supply with electric energy must be guaranteed any time. This applies in particular also during the implementation of complex electrical systems modernization projects. Highest demands on the project management, extensive experience and system knowledge are required. In the frame of the Modernization Program for the nuclear power plant Kozloduy unit 5 and 6 in Bulgaria Framatome ANP has approved its ability to implement a large scope of modernization measures during the refueling outages of the years 2003 to 2005. The Contract of the Modernization Program for the European Consortium Kozloduy (Framatome ANP, Atomenergoexport) was signed in July 1999 and became effective in June 2001. The project will be finished by May 2006, with the approval of the Updated Final Safety Analysis Report. The scope of hardware work has been implemented within 6 plant outages during the years 2002 to 2005. The focus of the Modernization Program is mainly oriented to nuclear safety aspects, with the aim of upgrading of the Units to a high safety level in compliance with international practice. A further section of the project is dedicated to upgrading of operational equipment. Framatome ANP personnel have shown that besides the technical challenges which had to be faced, also the intercultural and language barriers were successfully overcome. The good teamwork between the partners of the Consortium ECK, its Bulgarian subcontractors and with Kozloduy plant personnel has been an important success factor. (authors)

  16. NPP Prevlaka - Preparation of construction

    International Nuclear Information System (INIS)

    On the basis of study 'Optimal electricity generation structure till the year 2000' production of 3 x 500 MWe in nuclear power plants has been anticipated. Second Croatian-Slovenian NPP project will be based on the same principles the first one (NPP Krsko) was based on. Preconstruction investigation studies are performed at site Prevlaka on river Sava downstream of Zagreb. Licensing procedure has started with republic Urban countryside planning activities. Preconstruction activities are planned to be finished by the end of 1986. while the construction is expected to start during 1987. Parallel to investigation studies for NPP Prevlaka, evaluation of nuclear technology and reactor type is planned to be made. (author)

  17. Suomi NPP Ground System Performance

    Science.gov (United States)

    Grant, K. D.; Bergeron, C.

    2013-12-01

    The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather and environmental satellite system: the Joint Polar Satellite System (JPSS). JPSS will replace the afternoon orbit component and ground processing system of the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA. The JPSS satellites will carry a suite of sensors designed to collect meteorological, oceanographic, climatological and geophysical observations of the Earth. The first satellite in the JPSS constellation, known as the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite, was launched on 28 October 2011, and is currently undergoing product calibration and validation activities. As products reach a beta level of maturity, they are made available to the community through NOAA's Comprehensive Large Array-data Stewardship System (CLASS). CGS's data processing capability processes the satellite data from the Joint Polar Satellite System satellites to provide environmental data products (including Sensor Data Records (SDRs) and Environmental Data Records (EDRs)) to NOAA and Department of Defense (DoD) processing centers operated by the United States government. CGS is currently processing and delivering SDRs and EDRs for Suomi NPP and will continue through the lifetime of the Joint Polar Satellite System programs. Following the launch and sensor activation phase of the Suomi NPP mission, full volume data traffic is now flowing from the satellite through CGS's C3, data processing, and data delivery systems. Ground system performance is critical for this operational system. As part of early system checkout, Raytheon measured all aspects of data acquisition, routing, processing, and delivery to ensure operational performance requirements are met, and will continue to be met throughout the mission. Raytheon developed a tool to measure, categorize, and

  18. Selection of NPP for Kazakhstan

    International Nuclear Information System (INIS)

    Commercial NPP for Kazakhstan should to meet to several main requirements: 1). Safety operation (accident probability not more than 10-6 1/p. year). 2). High efficiency > 40 %. 3). Possibility of use for high-temperature chemistry and hydrogen production. 4). Possibility for manufacturing of considerable part of equipment in Kazakhstan. 5). Possibility for fuel production and reprocessing in Kazakhstan. 6). Independence from existence of large water-supply sources. Comparative analysis of several NPP with different reactors (WWR-1000, Candu, BREST, VG-400; graphite molten salt reactor) shows that NPP with the graphite molten salt reactor meets to all above requirements, but hydrogen production it is possible by more complete 4-stage technology, since coolant temperature is 800 Deg. C. The principle advantage is possibility of manufacturing of main equipment and fuel in Kazakhstan that reduce the cost of NPP construction and operation

  19. Fuel handling at Cernavoda 1 N.P.S. - commissioning and training philosophy

    International Nuclear Information System (INIS)

    Efficient operation of a Candu nuclear power plant depends greatly on the reliable and safe operation of the fuel handling system. Successful commissioning of the system is obviously a key aspect of the reliability of the system and this coupled with a rigorous training programme for the fuel handling staff will ensure the system's safe operation. This paper describes the philosophy used at Cernavoda 1 N.P.S. for the commissioning of the fuel handling systems and for the training of staff for operation and maintenance of these systems. The paper also reviews the commissioning programme, describing the milestones achieved and discussing some of the more interesting technical aspects which includes some unique Romanian input. In conclusion the paper looks at the organization of the mature fuel handling department from the operations, maintenance and technical support points of view and the long term plans for the future. (author). 1 fig

  20. Influence of the crustal and subcrustal Vrancea seismic sources on Cernavoda nuclear power plant site

    International Nuclear Information System (INIS)

    The basis of the seismic hazard assessment in different geographical regions with dense-populated areas and strategic objectives (dams, nuclear power plants, etc.) is the study of seismicity of the seismogenic sources which affect these sites. The purpose of this paper is to provide a complete set of information relative to the Vrancea seismic source (in the crust and the intermediate depth domains) that is fundamental for the seismic hazard evaluation at Cernavoda nuclear power plant site. The analysis that we propose has to deal with the following items: (1) geometrical definition of the seismic sources; (2) setting the earthquake catalog associated to each seismic source; (3) estimation of the maximum possible magnitude; (4) estimation of the frequency - magnitude relationship; (5) computation of the distribution function for focal distance; (6) correlation between focal depth and magnitude; (7) attenuation law. We discuss also the implications of the model parameters on the seismic hazard level. (authors)

  1. Psychology of NPP operation safety

    International Nuclear Information System (INIS)

    The book is devoted to psychologic investigations into different aspects of NPP operative personnel activities. The whole set of conditions on which successful and accident-free personnel operation depends, is analysed. Based on original engineering and socio-psychologic investigations complex psychologic support for NPP personnel and a system of training and upkeep of operative personnel skills are developed. The methods proposed have undergone a practical examination and proved their efficiency. 154 refs., 12 figs., 9 tabs

  2. The basis of NPP with WWER operation prolongation

    International Nuclear Information System (INIS)

    This monograph presents the generalization and analysis of normative-technical and methodical base on aging control and power unit operation prolongation of NPPs with WWER. The examples of technical status estimation and residual life of basis and auxiliary NPP equipment are given.

  3. Mochovce NPP 3,4 completion at the scratch line

    International Nuclear Information System (INIS)

    The article describes the chronology construction of the Mochovce NPP Units 3 and 4. Initial research and technical studies, preparatory works, important decisions, Slovak government involvement are described. Importance of the Nuclear Regulation Authority of the Slovak Republic decision is discussed. (author)

  4. NPP Temelin instrumentation and control system upgrade and verification

    International Nuclear Information System (INIS)

    Two units of Ver 1000 type of the Czech nuclear power plant Temelin, which are under construction are being upgraded with the latest instrumentation and control system delivered by WEC. To confirm that the functional design of the new Reactor Control and Limitation System, Turbine Control System and Plant Control System are in compliance with the Czech customer requirements and that these requirements are compatible with NPP Temelin upgraded technology, the verification of the control systems has been performed. The method of transient analysis has been applied. Some details of the NPP Temelin Reactor Control and Limitation System verification are presented.(author)

  5. Corrosion of copper-alloy tubes in the NPP cooling systems

    International Nuclear Information System (INIS)

    Factors efficiency on leaks in the NPP power unit steam turbine condensers are analyzed. Causes of corrosion - erosion wear of copper-alloy tubes are considered. A model for calculation of copper and copper-nickel alloy corrosion is proposed

  6. Construction of Belene NPP in Bulgaria

    International Nuclear Information System (INIS)

    Presentations concluding remarks: ASE has performed its scope of responsibilities under the Agreement of 29.11.2006 and has achieved great results regarding both the Technical part of the Project and its organization; Though there is a number of unsettled issues under the Project, in particular, the issue related to financing, ASE is willing to continue the Project and works on its development; The Russian Party believes that in case the activities under the Project are continued, Belene NPP will be constructed with high quality and within the time limits prescribed in the Agreement of 29.11.2006: 59 months before Unit 1 take-over into operation and 71 month before Unit 2 take-over into operation, starting from concreting of foundation slab of Unit 1 Reactor building

  7. Main principles of the Chernobyl' NPP zone development

    International Nuclear Information System (INIS)

    It is suggested to divide the Chernobyl' NPP zone into two parts, which are the alienation and evacuation (buffer) zones. The alienation zone includes the areas with greatest contamination around the Chernobyl' NPP. The population residence in this zone is forbidden. The watching method of working with short-time personnel residence is suggested to be used in this zone. The buffer zone is the territory out of the alienation zone boundaries including all settlements, from which the population is evacuated. Constant residence is permitted in the buffer zone for persons 50 and more years old with introduction of restrictions for diet and residence organization. The production activity in this zone includes operation of three units of the Chernobyl' NPP, works with the Ukrytie object and researches. Operations connected with radioactive waste processing and redisposal from places of storage is not recommended to be done. It is suggested to develop methods for local radioactive waste processing

  8. Impact of nuclear information on the public acceptance. Case study for young people in Cernavoda and Pitesti towns

    International Nuclear Information System (INIS)

    The general objective of this work was to investigate the impact of nuclear information on young people's knowledge and attitudes by using different Methods/Participatory Tools in an Educational Programme. The investigation started with a baseline survey of six groups of youngsters, three each from Pitesti and Cernavoda, which was completed early in 2005. After analysing the results an Educational Programme was proposed and developed following the FP6- COWAM2 Annual Seminar at Ljubljana. The Programme was produced by November 2005 and three methods were selected: classical methods usually used for school teaching, the discovery method, and a method involving simulation of a Local Committee. Three groups from Pitesti and four from Cernavoda attended the Programme, which was followed by a new questionnaire-based measurement (May 2006). (authors)

  9. Acceptable risk as the criteria for NPP efficiency and safety

    International Nuclear Information System (INIS)

    Four types of criteria of effective and safe operation of NPP power units are studied and formulated. Criterion types are formulated in risk terms of failure to comply problems, losses of capital outlays and territory (ecological risk), NPP personnel and population health damage. The structure of losses and profiles under conditions of the modern economic system is considered for the given types of criteria. The mathematical cost-profit model of a stochastic processes of power unit utilization is developed. The explicit functional form of the positive effect on the process trajectories for each of criterion types is constructed. The functional construction is based on the representation of a power unit as a generator of random events leading to power unit failure its damage or loss of territory, correspondingly

  10. Kozloduy NPP intranet portal, Bulgaria

    International Nuclear Information System (INIS)

    The Kozloduy NPP intranet portal was established in the late 1990s. The purpose of the portal was to provide access to general and frequently used information necessary for routine and daily work of the plant staff. Over the years the intranet site has been continuously improved and extended. The portal is now a standard tool for every member of plant personnel. The portal architecture has been designed on a modular basis and follows the general structure of the plant. The home page contains general, publicly accessible and frequently used information and corresponding links. Each major division maintains its own sub-portal, which services the specific needs of the division personnel. Hierarchical structure, pull down and shortcut menus facilitate navigation and provide a user friendly interface. The portal is based on FrameWork 1.1 and DotNetNuke and provides group and individual communications and data exchange. Most of the major plant databases related to documentation, plant operation, plant safety, plant systems data, training and human resources are accessible through the portal. Miscellaneous information and useful internal and external links also are available. Different types of communication services are organized through a separate server. Depending on their role and position, each staff member has been provided with an internal and/or external email address and an individually configured internet connection. For general purposes cable internet is accessible at several points, which are evenly located around the site, and there is also a secure wireless network connection. Search and retrieve functions are implemented through respective engines, which are incorporated into applications. The portal has a strongly defined access rights system. Anonymous access is prevented; page personalization is available only for limited specific cases. Figures show the home page and the path to Units 5 and 6 on-line technical parameters

  11. Emergency preparedness at Ignalina NPP

    International Nuclear Information System (INIS)

    Brief review of Ignalina NPP safety upgrading and personnel preparedness to act in cases of accidents is presented. Though great activities are performed in enhancing the plant operation safety, the Ignalina NPP management pays a lot of attention to preparedness for emergency elimination and take measures to stop emergency spreading. A new Ignalina NPP emergency preparedness plan was drawn up and became operational. It is the main document to carry out organizational, technical, medical, evacuation and other activities to protect plant personnel, population, the plant and the environment from accident consequences. Great assistance was rendered by Swedish experts in drawing this new emergency preparedness plan. The plan consists of 3 parts: general part, operative part and appendixes. The plan is applied to the Ignalina NPP personnel, Special and Fire Brigade and also to other contractor organizations personnel carrying out works at Ignalina NPP. There are set the following emergency classes: incident, emergency situation, alert, local emergency, general emergency. Separate intervention level corresponds to each emergency class. Overview of personnel training to act in case of an emergency is also presented

  12. Temelin NPP status and challenge

    International Nuclear Information System (INIS)

    In this presentation author deals with the NPP Temelin status and challenge. It was concluded that: - Temelin NPP was modified from the every beginning in order to meat internationally acceptable safety level; - IAEA, US and Western countries safety principles, criteria and requirements are mostly applied; - Number of international safety review missions confirmed this fact; All assessments of the Temelin NPP have been positive and all recommendations were carefully considered and either implemented or other equivalent solution was found. Temelin NPP Halliburton NUS audit in 1992 stated that Temelin can be licensable, but licensibility could not be assured unless the audit team's technical and programmatic recommendations are implemented. ENCONET Consulting (Austria) in 1998 stated that: - After modifications are fully implemented, Temelin NPP will be a much safer plant than originally designed and much more safer than some of the already operating WWER 1000 plants; - The process of compatibility was specifically assured by selecting prudent practices acceptable in the Western countries. IAEA mission on Safety issues resolution (1996) stated that: - It is recognized that the Czech Electric Company (CEZ) has made a large effort to improve the design of Temelin independently of the identification of safety issues by the IAEA

  13. Unification as a method to increase NPP component quality

    International Nuclear Information System (INIS)

    The experience of unifjcation of standard sizes of applied materials (rolled stock, tubes) of structural elements (threads, radii, grooves), detail and equipment units in the course of reactors development is investigated. Examples of unification of the WWER-1000 reactor pipe connections, equipment units, NPP equipment unification level with WWER-440 and WWER-1000 reactors are indicated. Coefficients of equipment applicability which in author's opinion must be 30-70% are given

  14. Implementing Safety Improvement Program (SIP-2) at Ignalina NPP

    International Nuclear Information System (INIS)

    Implementation of SIP-2 began in 1997. The programme comprises measures through introduction to implement recommendations of the Safety Analysis Report (SAR-1) concerning safety upgrading. Implementation of SIP-2 measures is a precondition for the validity of the operating licence for Unit 1 at the Ignalina NPP and safety of Unit 2 now being prepared for licensing is upgraded. Short information of the results of the Programme is presented

  15. Safety culture at Mochovce NPP

    International Nuclear Information System (INIS)

    This article presents the approach of Mochovce NPP to the Safety culture. It presents activities, which have been taken by Mochovce NPP up to date in the area of Safety culture enhancement with the aim of getting the term into the subconscious of each employee, and thus minimising the human factor impact on occurrence of operational events in all safety areas. The article furthermore presents the most essential information on how the elements characterising a continuous progress in reaching the planned Safety culture goals of the company management have been implemented at Mochovce NPP, as well as the management's efforts to get among the best nuclear power plant operators in this area and to be an example for the others. (author)

  16. Ignalina NPP Safety Improvement Program

    International Nuclear Information System (INIS)

    After 1991, when Lithuania became independent, the new safety improvement activities were initiated. Lithuania committed its responsibility for Ignalina NPP safety. However, it was lack of money for adequate safety improvement. Countries of Western Europe, USA and IAEA assisted Lithuania to carry out a comprehensive Ignalina NPP safety improvement program. Agreement with EBRD was signed in 1994. As a result of some bilateral and multilateral cooperation projects the Ignalina NPP Safety Improvement Programme (SIP-1) was accepted in 1993.This program was being implemented during 1993-1996. The Safety Analysis Report was issued in 1996. Review of the SAR was performed and RSR report was issued. On basis of both documents the Ignalina Safety Panel prepared recommendations for Lithuanian Government. These documents were used as a basis for the Safety Improvement Programme No.2. SIP-2 was accepted in 1997 and shall be finished in 2000

  17. Main public health risk factors nearby NPP construction site

    International Nuclear Information System (INIS)

    Full text:This paper discusses methods, which were developed based on original results and international recommendations, for processing and analysis of data on environmental monitoring to assess risk of adverse ecological consequences. The methods considered are also applicable for the data relevant to the territories nearby NPP construction site. Factor of both radiational and non-radiational origin, which may cause adverse health effects, were analyzed. An algorithm for assessment of environmental contamination was developed and coded in Delphi. The algorithm allows calculating integral contamination coefficient, getting information on safety state of a facility, and studying human body interaction with the environment under various conditions at work and home. Existing chemical and radiational parameters of the environment in the vicinity of the NPP construction site were considered. A potential environmental contamination form radioactive gaseous and aerosol emission during normal operation of 2 VVER-1200 units was estimated. Calculations showed that maximal soil surface contamination will not exceed 0.144 Bq/m2 (3.89·10-6 Ci/km2) during the first year of NPP operation. By the end of 60 years of NPP operation, maximal soil contamination will have increased by 1.67 Bq/m2 (4.5·10-5 Ci/km2). Fraction of soil contamination with radionuclides from NPP emission will be insignificant and will have reached 9.0·10-2 % by the end of 60 years of NPP operation. Individual annual exposure of population due to gaseous and aerosol emissions is 4.5·10-4 mSv (0.045% of the annual dose limit as recommended by radiation safety norms) in the maximal contamination spot at normal operation of 2 VVER-1200 units. Experimental measurements of pollutants' content in the atmospheric air on the territory being researched were done at Republic Center for Radiation Control and Environmental Monitoring. Experimentally obtained data on radioactive contamination of atmospheric air nearby

  18. Training of experts on NPP decommissioning

    International Nuclear Information System (INIS)

    The paper presents difficulties and problems in training of NPP decommissioning experts in Ukraine. The scientific and technical cluster is offered to be constructed as a territorial association of enterprises and organizations related to NPP decommissioning issues and spent nuclear fuel and radioactive waste management. The center is to be based on scientific and educational center in Slavutych, satellite city of Chornobyl NPP.

  19. Low level radwaste management and processing in Maanshan NPP

    International Nuclear Information System (INIS)

    Nuclear power plant like as the other power plant will generate technology waste. Owing to Nuclear still is a debatable topic for discussion, Nuclear radwaste including low level radwaste, high level spent fuel and nuclear operate safety become a focus point in Taiwan also in all world. Maanshan NPP is the only one PWR unit in Taiwan. In common understand, the Low Level radwaste generate from PWR unit is less than BWR. No matter what LLW generate quantity is reduced obviously, the government asks seriously restrain LLW quantity year by year. Maanshan NPP had reach a stable level in solidification waste, system spent resin, combustible and incombustible radwaste that generate from necessary maintenance. The further aim is keep waste generate under control, stable operate processing system and make a new processing technical to dispose spent resin. Maanshan NPP via technical cooperation to set HESS system with INER in one decade. Nowadays there are about 18 55 gallon drums per year in Maanshan NPP. LLW incinerator equipment designed by Maanshan and install at 7 years ago, there almost burns up all the combustible LLW that generate from commercial operation. The new equipment, wet-oxidation solidification process for treatment of spent radioactive ion-exchange resins plan will cooperate with INER and complete in 2014. It is estimated that the generation of solidified wastes of the NPS will be reduced to about 1/3 volume of that currently generated. (author)

  20. NPP Krsko secondary side analysis

    International Nuclear Information System (INIS)

    The purpose of this work is to analyze secondary side thermohydraulics response on steam generator tube plugging in order to ensure nominal NPP power. We had established that the additional opening of the governing valve No. 3 and 4 can compensate pressure drop caused by steam generator tube plugging. Two main steam flows with four governing valves were simulated. Steam expansion in turbine and feed water system was modeled separately. All important process point and steam moisture changes impact on nominal NPP power were analysed. (author)

  1. Radioactive wastes management of NPP

    International Nuclear Information System (INIS)

    Modern knowledge in the field of radiation waste management on example of the most serious man-made accident at Chernobyl NPP are illuminated. This nuclear power plant that after accident in 1986 became in definite aspect an experimental scientific ground, includes all variety of problems which have to be solved by NPP personnel and specialists from scientific organizations. This book is aimed for large sphere of readers. It will be useful for students, engineers, specialists and those working in the field of nuclear power, ionizing source and radiation technology use for acquiring modern experience in nuclear material management

  2. Nuclear Oversight Function at Krsko NPP

    International Nuclear Information System (INIS)

    industry experience (events, good practice etc.) in its assessment. That becomes most important in small utilities (with one nuclear unit only) such as the Krsko NPP. Involvement in international organizations is therefore a must and not an option for such organization. The Krsko NPP is today widely involved in various international organizations. Both sides are deriving substantial benefits from such cooperation.(author).

  3. Preparation for Early Termination of Ignalina NPP Operation

    Energy Technology Data Exchange (ETDEWEB)

    Poskas, P.; Poskas, R.

    2003-02-26

    Seimas (Parliament of Lithuania) approved updated National Energy strategy where it is indicated that first Unit will be shutdown before the year 2005 and second Unit in 2009 if funding for decommissioning is available from EU and other donors. In accordance to Ignalina NPP Unit 1 Closure Law the Government of Lithuania approved the Ignalina NPP Unit 1 Decommissioning Program until year 2005. For enforcement of this program, the plan of measures for implementation of the program was prepared and approved by the Minister of Economy. The plan consists of two parts, namely technical- environmental and social-economic. Technical-environmental measures are mostly oriented to the safe management of spent nuclear fuel and operational radioactive waste stored at the plant and preparation of licensing documents for Unit 1 decommissioning. Social-economic measures are oriented to mitigate negative social and economic impact on Lithuania, inhabitants of the region, and, particularly, o n the staff of Ignalina NPP by means of creating favorable conditions for a balanced social and economic development of the region. In this paper analysis of planned activities, licensing requirements for decommissioning, progress in preparation of the Final Decommissioning Plan is discussed.

  4. Feed water distribution pipe replacement at Loviisa NPP

    Energy Technology Data Exchange (ETDEWEB)

    Savolainen, S.; Elsing, B. [Imatran Voima Loviisa NPP (Finland)

    1995-12-31

    Imatran Voima Oy operates two WWER-440 reactors. Unit 1 has been operating since 1977 and unit 2 since 1981. First damages of feed water distribution (FWD) pipe were observed in 1989. The FWD-pipe T-connection had suffered from severe erosion corrosion damages. Similar damages have been been found also in other WWER-440 type NPPs. In 1989 the nozzles of the steam generator YB11 were inspected. No signs of the damages or signs of erosion were detected. The first damaged nozzles were found in 1992 in steam generators of both units. In 1992 it was started studying different possibilities to either repair or replace the damaged FWD-pipes. Due to the difficult conditions for repairing the damaged nozzles it was decided to study different FWD-pipe constructions. In 1991 two new feedwater distributors had been implemented at Dukovany NPP designed by Vitckovice company. Additionally OKB Gidropress had presented their design for new collector. In spring 1994 all the six steam generators of Rovno NPP unit 1 were replaced with FWD-pipes designed by OKB Gidropress. After the implementation an experimental program with the new systems was carried out. Due to the successful experiments at Rovno NPP Unit 1 it was decided to implement `Gidropress solution` during 1994 refueling outage into the steam generator YB52 at Loviisa 2. The object of this paper is to discuss the new FWD-pipe and its effects on the plant safety during normal and accident conditions. (orig.).

  5. Detection of primary coolant leaks in NPP

    International Nuclear Information System (INIS)

    The thermo-hydraulic analyses of the SG box behaviour of Kozloduy NPP units 3 and 4 in case of small primary circuit leaks and during normal operation of the existing ventilation systems in order to determine the detectable leakages from the primary circuit by analysing different parameters used for the purposes of 'Leak before break' concept, performed by ENPRO Consult Ltd. are presented. The following methods for leak detection: measurement of relative air humidity in SG box (can be used for detection of leaks with flow rate 3.78 l/min within one hour at ambient parameters - temperature 400 - 600C and relative humidity form 30% to 60%); measurement of water level in SG box sumps (can not be used for reliable detection of small primary circuit leakages with flow rate about 3.78 l/min); measurement of gaseous radioactivity in SG box( can be used as a general global indication for detection of small leakages from the primary circuit); measurement of condensate flow after the air coolers of P-1 venting system (can be used for primary circuit leak detection) are considered. For determination of the confinement behaviour, a model used with computer code MELCOR has been developed by ENPRO Consult Ltd. A brief summary based on the capabilities of the different methods of leak detection, from the point of view of the applicability of a particular method is given. For both Units 3 and 4 of Kozloduy NPP a qualified complex system for small leak detection is planned to be constructed. Such a system has to unite the following systems: acoustic system for leak detection 'ALUS'; system for control of the tightness of the main primary circuit pipelines by monitoring the local humidity; system for primary circuit leakage detection by measuring condensate run-off in collecting tank after ventilation system P-1 air coolers

  6. Verification of SAPFIR95andRC code package against operational data of WWER units

    International Nuclear Information System (INIS)

    The previous report on the same subject represents a brief description of procedure laid down in the code package SAPFIR 95 and RC and gives calculation results of fuel cycles by operational data of WWER-440 power Units (Kola NPP, Unit No.1 and Dukovany NPP, Unit No.2). The given paper additionally represents simulation results of fuel cycles as compared with operational data of Dukovany NPP, Unit No.3 and power Units with WWER-1000 reactors (Volgodon NPP, Unit No.1, Kalinin NPP, Unit No.3) (Authors)

  7. Evaluation of radiation impacts of spent nuclear fuel storage (ISP-2) of Chernobyl NPP

    International Nuclear Information System (INIS)

    The estimation of radiation impacts during normal operation of dry spent fuel storage facility for ChNPP RBMK reactors, designed for long-term storage of spent fuel assemblies (SFA), which originated from the operation 1,2,and 3 units ChNPP was made. It is shown that the maximum concentration of radionuclides in the air near the ISF-2 well below allowable concentration for the population, and additional pollution is negligible in comparison with the existing one

  8. Geometric processes model in the NPP equipment ageing statistical detection problem

    International Nuclear Information System (INIS)

    Methodology has been described that allows to evaluate the NPP equipment non-homogeneity failure rate. Along with the point estimate of the reliability index its interval estimate algorithm was built, which allows to check the statistical significance of hypotheses about the parameter. The decision criterion algorithm with a prescribed level of significance is described in detail. A number of test cases are analyzed to detect heterogeneity. Real data including Novovoronezh NPP WWER-1000 5 unit recharge and born control failures was processed

  9. Experience of operation, design and improvement of projects for NPP with WWER-440 reactor

    International Nuclear Information System (INIS)

    In the article there are presented basic design and operation parameters of power supply units of WWER-440 reactors of different generation. There are being discussed requirements on safety providing, results of accident mode operation analysis and materials of safety technical substantiations. There are given major direction of study conducted to substantiate design improvement and peculiarities of new generation of NPP with WWER-440. There are given main technical and economic factors necessary to evaluate efficiency of NPP with WWER-440

  10. User experiences using the operator support systems SCORPIO and SPDS at Kola NPP

    International Nuclear Information System (INIS)

    Full text: During the years from 2000 to 2004 a Safety Parameter Display System (SPDS) and a SCORPIO-VVER system have been installed and put into operation at Kola NPP in northern Russia. The projects have been carried out in co-operation with Finnish and Russian subcontractors with IFE, Halden, as the main contractor and the project manager. Both projects have been defined within the Norwegian Assistance Programme to Nuclear Installations at the Kola Peninsula and financed by the Norwegian government. The SPDS project has also been partly financed by the Finnish government. The Kola SPDS, which is based on a system originally developed for the Loviisa Nuclear Power Plant in Finland, was installed and put into operation on Kola NPP units 1 and 2 in April 2000 and on Kola NPP units 3 and 4 in March 2004. The system has been licensed and approved by Russian authority (GAN) for use in the control room environment. The SCORPIO-VVER system is based on the SCORPIO-VVER framework developed for Dukovany NPP, Czech Republic and Bohunice NPP, Slovak Republic. Further, the experience gained with the SCORPIO framework developed for Western PWRs have been utilised. The SCORPIO-VVER system was installed and put into operation at Kola NPP Nuclear Safety Centre in December 2003 for core monitoring on units 3 and 4. The user experiences by introducing the SPDS and the SCORPIO-VVER system at Kola NPP are so far very positive. By introducing an SPDS at Kola NPP, the process safety status (single or combinations of signals) is presented for the operator in a centralized location (on one screen) in the control room and in a form that makes it easier to obtain a quick assessment of the process safety status. According to feedback from control room personnel the SPDS has enhanced the monitoring of the safety status of the plant. The reactor core is the most central component of a nuclear power plant and a comprehensive core monitoring system is very important for maintaining reactor

  11. Development of NPP personnel training system in Ukraine

    International Nuclear Information System (INIS)

    Full text: Modern personnel training and retraining system is a guarantee of NPPs safe reliable operation. NPPs personnel's training is conducted at Kyiv and Odessa Polytechnic universities, Sevastopol Institute of Nuclear Energy and Industry. Since the time when independence of Ukraine was proclaimed personnel training system was created directly at NPPs. This system is based on the latest legislation framework, developed subject to IAEA recommendations, gained international experience in the field of personnel training in view of increased demands to personnel qualification. Training Centers, formed at each plant, form one of the main components of NPP personnel training. Total number of personnel at these centers is 436 persons, including 160 instructors. Personnel's training at Training Centers is performed in accordance with standard programs. At that, special consideration is given to maintaining qualification of the licensed personnel. Simulator training base was created by joint efforts of specialists from the USA, Russia and Ukraine. In 1993 the first in Ukraine full scope simulator of the main control room began to work at Zaporizhzhya NPP. The simulator is designed for acquiring by personnel of skills in reactor control under normal operation, off-normal conditions and emergency situations. In 2002 the second full scope simulator was put into operation at Zaporizhzhya NPP. Now the development of the third full scope simulator is on going. In December 1997 a similar simulator was put into operation at Khmelnitsky NPP. In May 2001 a full scope simulator for Rivne NPP unit 3 personnel training was put into pilot operation. In 2002 one more VVER-440 simulator for units 1 and 2 was put into operation at Rivne NPP. In 2000 Zaporizhzhya NPP obtained first license to initial and continuing training for operating personnel. Now all NPPs Training Centers have obtained similar licenses. Establishing manager training system and replacement reserves for National

  12. Increase in capital costs for US NPP construction

    International Nuclear Information System (INIS)

    During 15 years (from 1967 to 1981) the US nuclear power engineering development was characterised by constant growth of estimated capital costs and planned terms of NPP construction. In fact, the annual growth of costs indicated in this period made up averagely 25%. Such a high growth became one of the main reasons for excluding in 1972-1983 108 nuclear power units from NPP construction programs, planned by various power supply companies. Sufficient reduction of electric load growth rate from 7% (a stable number typical of the period up to 1973) to 2.7 per a year, forecasted for 1984-1993, can be considered as one of the main reasons for nuclear power growing depression which has begun since the end of 1978. Moreover, experts believe, that hardening the requirements to NPP operation safety, development of an excessively large number of norms and specifications concerning environmental protection, delay in terms of NPP construction and sufficient growth of capital costs for their construction, also played an important role

  13. Implementation of the II. Stage decommissioning of A1 NPP

    International Nuclear Information System (INIS)

    Presentation is focused on the implementation of the II. stage decommissioning of A1 NPP. Introductory part focuses on brief characteristics of the power plant with a history of operation, basic technical parameters and actions that were made after operation. The next section describes the basic schedule for decommissioning, structure of management and implementation of the II. stage decommissioning of the A1 NPP and objectives of the individual stages. The last and largest part of the presentation is devoted to detailed description of the II. stage decommissioning of the A1 NPP, its individual tasks and verbal and visual description of the activities that were performed. Presented is decommissioning of the technology and construction of external objects NPP A1 including storage tanks for liquid RAW, next are presented activities carried out in the Main Production Unit - decommissioning of non-operating technologies in various places/rooms, management of waste arising from these activities, treatment of case of A1 long-term spent fuel storage and long-term spent fuel storage. The subsequent section is devoted to the management and handling of contaminated soil, concrete and construction waste, including management of VLLW. (authors)

  14. Low level radioactive waste disposal in Kozloduy NPP in Bulgaria

    International Nuclear Information System (INIS)

    Kozloduy NPP is the biggest power plant in the Republic of Bulgaria. It is in operation since 1974 and for the past 25 years it has generated over 263 billion kWh electric power. The NPP share in the total electric production in 1998 was about 50%. It has six units in operation - four WWER 440 B-230 and two WWER 1000 B-320. In the nuclear reactor operation the generation of radioactive waste (RAW) is an inevitable process. The waste must be conditioned, stored and disposed of in a safe manner. There are no national radioactive waste disposal facilities, for waste generated by an NPP, in Bulgaria to the moment. This situation necessitates the storage of operational RAW to be carried out on site for a long period of time (30 to 50 years). Following the principle for protection of human health and environment now and in the future, Kozloduy NPP adopted the concept for conditioning the RAW to a stable solid form and placing the waste in a package which should keep its features for a sufficiently long term so that the package can be safely transported to the disposal site. (author)

  15. Report of the review of the safety improvement programme for South Ukraine NPP units 1 and 2 and to identify the safety issues of ''small series'' WWER-1000 NPPs. South Ukraine Yuzhnoukrainsk, Nikolaev Region Ukraine, 8 to 19 July 1996. Draft

    International Nuclear Information System (INIS)

    According to the Ukrainian request the purpose of the IAEA experts' mission was to review the safety improvement programme for South Ukraine NPP Units 1 and 2 in order to advise on the completeness and adequacy of safety improvements implemented and/or proposed. Another purpose of the mission was to identify major design and operational deficiencies as a basis to compile a consolidated list of generic safety issues for the units of the 'small series'' of WWER-1000 reactors (''Issue Book for ''small series'' WWER-1000 NPPs). Conclusions and recommendations from the IAEA mission are based on the combined expertise of the international group of experts who composed the team. They are intended to assist national authorities and plant operators who have the sole responsibilities for the regulation and safe operation. tabs

  16. Necessity of Monitoring the Sea Level and Temperature near the NPP site

    Energy Technology Data Exchange (ETDEWEB)

    Hyun, Seung Gyu; Choi, Ho Seon; Jin, So Beom [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2009-05-15

    Twenty units of Nuclear Power Plant(hereinafter NPP) are operating and six units are under construction in domestic regions. In particular, Kori unit 1 has been operating for over 30 years. All of the interior NPP are located in coastal areas and use the sea water for the cooling system. Therefore, the change of sea level and temperature could directly or indirectly affect the safety of NPP. At the stage of the construction, the design basis sea level and the temperature of sea water are estimated and the safety of a NPP is confirmed. Because of the change of the coastal bathymetry and the shoreline and climate change after the construction of NPP, however, the possibility change in the sea level and temperature is higher. Thus, the continuous monitoring data of the sea level and temperature near the NPP site are required for re-evaluating the design basis flood and the temperature of sea water. In this paper, the necessity on monitoring the sea level and temperature which are the key factors for the design basis flood and the temperature of sea water is reviewed.

  17. Modelling of Krsko NPP using MELCOR

    International Nuclear Information System (INIS)

    MELCOR, severe accident analysis tool has been used to form a base for nodalization of Krsko Nuclear Power Plant. There have been number of analysis using other integral computer packages performed in the past including MAAP, and STCP programs as well as mechanistic computer packages such as RELAP5. MELCOR is state of the art program maintained by United States Nuclear Regulatory Commission and is currently used at University of Maribor to assess some of the accident sequences. This contribution presents the database development and its main characteristics, including some of the aspects unused by current analysis and foreseen in the future. Advantages and shortcomings of the database are discussed and future plans including proposed improvements are presented. In addition to the database few test results are presented to show the general behaviour of Krsko NPP simulation. (author)

  18. Solid radioactive waste processing facility of the NPP Leningrad

    International Nuclear Information System (INIS)

    On behalf of the Russian Company Rosenergoatom NUKEM Technologies GmbH is planning and constructing a complete facility for the processing of solid low- and medium-active radioactive wastes. The NPP Leningrad comprises 4 units of RBMK-1000 reactors, the plant life has been extended by 15 years, the first unit is to be decommissioned in 2018. The construction of four new units is planned. NUKEM is in charge of planning, manufacture, construction and startup of the following facilities: sorting, internal transport, combustion and waste gas cleaning, emission surveillance, compacting, packaging and radiological measurement.

  19. Lessons learnt from Ignalina NPP decommissioning project

    International Nuclear Information System (INIS)

    The Ignalina Nuclear Power Plant (INPP) is located in Lithuania, 130 km north of Vilnius, and consists of two 1500 MWe RBMK type units, commissioned respectively in December 1983 and August 1987. On the 1. of May 2004, the Republic of Lithuania became a member of the European Union. With the protocol on the Ignalina Nuclear Power in Lithuania which is annexed to the Accession Treaty, the Contracting Parties have agreed: - On Lithuanian side, to commit closure of unit 1 of INPP before 2005 and of Unit 2 by 31 December 2009; - On European Union side, to provide adequate additional Community assistance to the efforts of Lithuania to decommission INPP. The paper is divided in two parts. The first part describes how, starting from this agreement, the project was launched and organized, what is its present status and which activities are planned to reach the final ambitious objective of a green field. To give a global picture, the content of the different projects that were defined and the licensing process will also be presented. In the second part, the paper will focus on the lessons learnt. It will explain the difficulties encountered to define the decommissioning strategy, considering both immediate or differed dismantling options and why the first option was finally selected. The paper will mention other challenges and problems that the different actors of the project faced and how they were managed and solved. The paper will be written by representatives of the Ignalina NPP and of the Project Management Unit. (author)

  20. Risk indicators at Cofrentes NPP

    International Nuclear Information System (INIS)

    Following the tend to try to find indicators to show the excellence in the performance where Nuclear Power Plants are currently involved, Cofrentes NPP are managing several indicators related with risk. The concept of risk is classically associated with the product RISK = PROBABILITY * DAMAGE So what a risk based indicator will show is the probability of having a 'damage'. Speaking about a period of time, we will have frequencies of having 'damages'. What is call 'damage' can be differently interpreted depending of what we concern. In western NPP is very extended the concept of 'core damage', meaning the loss of fuel integrity, as a final state to avoid. This have carried in most of western NPP to develop a Probabilistic Risk Assessment (PRA/PSA), that using technical based in fault trees and event trees models, looks for the frequency to reach core damage. The PSA in Cofrentes NPP has been deeply applied to find weakness in the design and procedures, prioritizations in maintenance activities, quality assurance requirements, justifications to continued operation, and others. A Risk Monitor based in PSA models (and so monitoring the Core Damage Frequency) has been developed and is currently installed in the Control Room to help operators to control the risk associated with each configuration of availability or unavailability of equipments. This PSA Monitor is the source for some indicators that Cofrentes NPP has defined and are sharing with IAEA trying to find an standard. Maximum Core Damage Frequency reached and accumulated annual probability is calculated and compared with expected values and with predefined limits. As the PSA in Cofrentes NPP is only for at power Operations, there has been developed a methodology based on NUMARC 91-06 to measure and control the risk during shutdowns. The 'damage' here is a concept related with the safety functions. Some coefficients are applied to each configuration according with how the safety functions are fulfilled (defense

  1. The Application of Paleoseismology to NPP Seismic Hazard Assessment

    International Nuclear Information System (INIS)

    Paleoseismic Investigations around Onagawa NPP: Onagawa NPP is located in northeast Japan. It lies on an overriding plate, the North American plate, and is characterized by east-west compressive stress field. The Japan Trench, approximately 200 km to the east of Onagawa NPP, is an interfacial boundary where the Pacific plate moves beneath the North American plate. Because of that, three types of earthquake can occur at the NPP site: crustal intraplate, subduction interface and intra-slab earthquakes. In this Section we will only deal with crustal intraplate earthquakes. Paleotsunami Investigations around the Fukushima area: In the application document for establishment permit of the Fukushima Dai-ichi NPP, the subject tsunami source was the 1960 Chile Earthquake (M 9.5) and the design basis tsunami water level was 3.1 m. In 2002, TEPCO evaluated the design tsunami height based on the ‘Tsunami Assessment Method for Nuclear Power Plants in Japan’ voluntarily assessing the 1938 Fukushima offshore earthquake (M 7.9) as M 8.0, and the highest water level of each Unit was set to levels between 5.4 and 5.7 m. At the 32nd Joint Working Group for Earthquake, Tsunami, Geology, and Foundations under the Seismic and Structural Design Subcommittee (June 24, 2009), held in order to conduct examinations related to earthquakes, it was pointed out that although the investigation on tsunamis caused by the Jogan earthquake in AD 869 was reported by National Institute of Advanced Industrial Science and Technology (AIST) and Tohoku University, the earthquake causing the tsunami was not dealt with. Regarding this, Nuclear and Industrial Safety Agency requested TEPCO at the 33rd Joint Working Group (July 13th, 2009) to take into account the Jogan earthquake for evaluating design tsunami height when new knowledge on this tsunami is obtained. The survey reports by AIST and Tohoku University were summarized by HERP. Several examples of them follow

  2. Artificial intelligence and NPP safety

    International Nuclear Information System (INIS)

    The main tasks of the software for probabilistic safety analysis, thermal hydraulic analysis and probabilistic risk assessment are discussed. Their combination for direct improvement of NPP operation through information support of the staff is stressed. The general philosophy (in-depth protection) of computerized Emergency Response Guidelines (ERGs) - symptom based (safety parameters) and events-oriented (types of accident) is pointed out. The use of expert systems for proper diagnosing of the accident, its forecasting and finding the way of overcoming it is shown. Mandatory components of the modern management policy in abnormal situations are: the ERGs, the installation of Safety Parameter Display panels, the availability of an safety engineer (superviser); local, regional and national systems for monitoring of the radiation environment within and outside the NPP; local protection centres for maintenance in the case of accident. The importance of verification and validation (V and V) approach and benchmark exercise is stressed. Some peculiarities of the on-going implementation of the computerized information system for radiation control in Kozloduj NPP are discussed. 3 figs, 7 refs

  3. Polish media and public opinion on NPP Mochovce commissioning

    International Nuclear Information System (INIS)

    The so called 'Mochovce Problem' was one of the major topics in Polish media in the period from May to July 1998. The nuclear power plant commissioning caused an unexpectedly strong reaction, especially in the newspapers, slightly less so in electronic media. Faced with clearly hostile media reaction to Mochovce NPP, the National Atomic Energy Agency representatives, together with atomic and nuclear experts, undertook to change these attitudes. In numerous interviews, letters to the editors and talks with journalists, they attempted to correct the mistakes, explain the true safety situation in the nuclear power plant, by whom it was constructed, who supervised and tested the systems and so on. The completion of Mochovce NPP construction improved significantly the electricity balance in Slovakia, thus decreasing the pressure for continuing the operation of older Bohunice V1 units beyond their design lifetime. For this reason, as well as in view of striving for improvement in environmental factors beyond Polish southern border, especially after Kyoto/97 decisions on greenhouse gases emissions, the public opinion in Poland should support the Mochovce NPP construction. In 1996 Poland has signed with Slovakia a bilateral inter-governmental agreement on the prompt notification on nuclear accidents and on the cooperation in the nuclear safety and radiological protection matters. On the basis of this agreement the experts from Polish National Atomic Energy Agency are in perpetual contact with Slovakian Nuclear Regulatory Body and in each and every moment can obtain full and comprehensive information on the plant parameters iportant for nuclear safety. The experts explanations, together with the NAEA top management visit to the plant itself, brought some results. The media became less aggressive, and Polish public and authorities - contrary to the Austrians - do not protest loudly against the commissioning of this newest European NPP. Now, in December 1998, the tune of

  4. Experience from the Inspection of Licensees' Outage Activities, Including Fire Protection Programmes, Event Response Inspections, and the Impact of the Fukushima Daiichi NPP Accident on Inspection Programmes. Workshop Proceedings, Chattanooga, Tennessee, United States, 7-10 April 2014

    International Nuclear Information System (INIS)

    The main purpose of the workshop was to provide a forum of exchange of information on the regulatory inspection activities. Participants had the opportunity to meet with their counterparts from other countries and organisations to discuss current and future issues on the selected topics. They developed conclusions regarding these issues and hopefully, identified methods to help improve their own inspection programmes. The NEA Committee on Nuclear Regulatory Activities (CNRA) believes that an essential factor in ensuring the safety of nuclear installations is the continuing exchange and analysis of technical information and data. To facilitate this exchange the Committee has established working groups and groups of experts in specialised topics. The Working Group on Inspection Practices (WGIP) was formed in 1990 with the mandate '..to concentrate on the conduct of inspections and how the effectiveness of inspections could be evaluated..'. The WGIP facilitates the exchange of information and experience related to regulatory safety inspections between CNRA member countries. These proceedings cover the 12. International Workshop held by WGIP on regulatory inspection activities. This workshop, which is the twelfth in a series, along with many other activities performed by the Working Group, is directed towards this goal. The consensus from participants at previous workshops, noted that the value of meeting with people from other inspection organisations was one of the most important achievements. The focus of this workshop was on experience gained from regulatory inspection activities in three areas: - Inspection of Outage Activities Including Fire Protection Programmes. - Event Response Inspections. - The Impact of Inspection Programmes of the Fukushima Daiichi Nuclear Power Plant (NPP) Accident. The main objectives of the WGIP workshops are to enable inspectors to meet with inspectors from other organisations, to exchange information regarding regulatory inspection

  5. The kinetics of aerosol particle formation and removal in NPP severe accidents

    Science.gov (United States)

    Zatevakhin, Mikhail A.; Arefiev, Valentin K.; Semashko, Sergey E.; Dolganov, Rostislav A.

    2016-06-01

    Severe Nuclear Power Plant (NPP) accidents are accompanied by release of a massive amount of energy, radioactive products and hydrogen into the atmosphere of the NPP containment. A valid estimation of consequences of such accidents can only be carried out through the use of the integrated codes comprising a description of the basic processes which determine the consequences. A brief description of a coupled aerosol and thermal-hydraulic code to be used for the calculation of the aerosol kinetics within the NPP containment in case of a severe accident is given. The code comprises a KIN aerosol unit integrated into the KUPOL-M thermal-hydraulic code. Some features of aerosol behavior in severe NPP accidents are briefly described.

  6. NPP technical and economical parameters and safety

    International Nuclear Information System (INIS)

    The problem of the ratio between technical and economic indices of NPP and its safety has been considered. It is suggested that safety indices of NPP projected should be made allowance for, when calculating net cost of electric power generated so, that NPP with higher safety indices remained competitive. The problem can be solved using a special invariance fund for compensating the costs of protection measures taken. The amount of contribution is to be the higher, the lower are safety indices of NPP. 2 refs

  7. Ignalina NPP: living and working conditions

    International Nuclear Information System (INIS)

    The conference was devoted to discuss the social problems related with the operation of Ignalina NPP. The main topics are the following: analysis of public opinion of surrounding region of Ignalina NPP including neighbouring Daugavpils district in Latvia, environment impact evaluation of Daugavpils district, assessment of the influence of Ignalina NPP operation to the development of business in the region, investigation of problems of Visaginas town - residence of Ignalina NPP personnel. The specificity of Visaginas (former Sniechkus) is defined by the majority of non-native Lithuanians living there. Cultural transformation and political organization of the region were surveyed as well

  8. Effective long term operation for Dukovany NPP

    International Nuclear Information System (INIS)

    Dukovany NPP now started third decade of service that is also its last decade of design life time. It is clear that the NPP has all considerations for service past the design life time called Long Term Operation (LTO). This LTO has two main aspects, technical and economical, that influence each other. From technical view the age of NPP systems, structures and components (SSCs) affects negatively the ability to perform necessary design changes in a good quality and also the long lived SSC reliability. These possible impacts have also their safety aspects and to obtain regulatory body agreement with LTO of NPP it is necessary to show that these impacts are acceptable. It means to show that all applied design changes are done in agreement with NPP design bases (DB) and all ageing impacts on SSCs functions important for safety are properly managed. From economical view that is significant for NPP owner it is necessary to demonstrate a required profitability of investment for effective LTO. These are reasons why Dukovany NPP performs three following projects: - Safety design bases collation and reconstitution, - Enhancement of plant life management program (New program preparation), - Technical-economical (TE) study of NPP LTO. All of these projects are managed by Nuclear Research Institute Rez plc (NRI) and performed in close cooperation with NPP staff and different co-operaters. This presentation will be concentrated to the last named project.

  9. Metamorphosis of NPP A1, V1, V2

    International Nuclear Information System (INIS)

    In this book the history of construction, commissioning and exploitation of NPP A1, NPP V1 and NPP V2 in Jaslovske Bohunice is presented on documentary photos. Vicinity around of these NPPs is presented, too

  10. The role of research programs and commercial contracts for increase of economic competitiveness and development at INR Pitesti

    International Nuclear Information System (INIS)

    In the period in which globalization is increasing, one of the strategic objectives of the institute is to focus on those activities which help developing of services, products and technologies, applicable in nuclear industry, environment protection and medicine. One way to sustain INR activity is the technological transfer which ensures availability of research results by carrying out of R and D contracts in priority areas and of contracts with economical agents for the supply of services, products, technologies, such as: - Materials irradiation for medicine, industry and research; - Neutron Activation Analysis (NAA) and prompt gamma spectrometry for Cernavoda NPP - Unit 1; - Control and testing: non-destructive examination, functional tests of samples and equipment from Cernavoda NPP - Unit 1; - Characterization, conditioning and treatment of radioactive wastes for NPP- Cernavoda, Unit 1, Nuclear Fuel Plant (FCN) - Pitesti; - Measurement of isotopes concentration in environmental samples; -Corrosion experiments in static autoclaves and experiments regarding microbial corrosion for NPP Cernavoda Unit 1 and FCN Pitesti; - Nuclear consultancy for Cernavoda NPP - Unit 1 and Unit 2; - Stainless steel casks for radwaste; - Containers for heavy water; - Training and practice for students at the Universities of Pitesti, Bucuresti, Brasov. The paper presents the main areas where the results obtained in R and D programs can be applied, their implementation can be done, and the status of contracts and their importance for INR Pitesti and Romanian society development, as well. (authors)

  11. NPP Evaluation, backfitting and life extension. An engineering viewpoint

    International Nuclear Information System (INIS)

    During the decade of the 80s, the Owners of the two oldest operating plants in Spain designed and built during the 60s - namely, Jose Cabrera NPP, a Westinghouse PWR, and Santa Maria de Garona NPP, a GE BWR- undertook the following important programs: 1. A far-reaching Systematic Evaluation Program (SEP) for the Jose Cabrera NPP consisting in the systematic safety review of the plant design, followed by the necessary hardware modifications, to upgrade it and make it comply with current safety criteria, and a Plant Upgrading Program for the Garona Nuclear Station focusing on specific topics affecting GE BWR Mark-I type plants of the same vintage. 2. A Remaining Life Management Program to ensure that the units, after extensive backfittings and high capital investment, would complete their design life, leaving open the option for plant life extension. These two units are today considered by the Spanish nuclear industry as the pilot plants for Plant Life Extension (PLEX) programs for PWRs and BWRs in our country The purpose of this paper is to summarize the principal lessons learned from EMPRESARIOS AGRUPADOS' participation as an architect-engineering organization in the engineering, design and implementation of these Programs. They are practical examples of positive experience which could be considered as a reference when carrying out similar programs for other plants. (author)

  12. Enhancing NPP Safety Through an Effective Dependability Management

    International Nuclear Information System (INIS)

    Taking into account the importance of the continuous improvement of the performance and reliability of a NPP and practical measures to strengthen nuclear safety and security, it is to be noted that a good management for a nuclear power reactor involves a ''good dependability management'' of the activities, such as: Reliability, Availability, Maintainability (RAM) and maintenance support. In order to evaluate certain safety assessment criteria intended to be applied at the level of the nuclear reactor unit management, equipment dependability indicators and their impact over the availability and reactor safety have to be evaluated. Reactor equipment dependability indicators provide a quantitative indication of equipment RAM performances (Reliability, Availability and Maintenance). One of the important benefits of maintenance and failure data gathering is that it can be used as a support of probabilistic safety assessment (PSA). Also, a good dependability management implementation may be used to complement reactor level unit performance indicators in the field of safe operation, maintenance and improving operating parameters, as well as for Strengthening Safety and Improving Reliability of a NPP. This paper underlines the importance of nuclear safety and security as prerequisites for nuclear power. In addition, it demonstrates how different technical aspects, through implementation of a good dependability management, contribute to a strengthened safety and an improvement of availability of the NPP through dependability indicators determination and evaluation. (author)

  13. COMPARISON OF NOVORONEZH UNIT 5 NPP AND SOUTH UKRAINE UNIT 1 NPP LEVEL I PRA RESULTS.

    Energy Technology Data Exchange (ETDEWEB)

    MUSICKI,Z.; GINSBERG,T.

    2002-04-18

    This paper describes a study undertaken to explain the risk profile differences in the results of PRAs of two similar WER-1000 nuclear power plants. The risk profile differences are particularly significant in the area of small steam/feedwater line breaks, small-small LOCAs, support system initiators and containment bypass initiators. A top level (limited depth) approach was used in which we studied design differences, major assumptions, data differences, and also compared the two PRA analyses on an element-by-element basis in order to discern the major causative factors for the risk profile differences. We conclude that the major risk profile differences are due to differences in assumptions and engineering judgment (possibly combined with some design and data differences) involved in treatment of uncertain physical phenomena (primarily sump plugging in LOCAs and turbine building steaming effects in secondary system breaks). Additional major differences are attributable to support system characteristics.

  14. Water chemistry of secondary circuit and SG currently status NPP 'Kozloduy' 3

    International Nuclear Information System (INIS)

    The author gives a historical review of the secondary water chemistry regimes of NPP Kozloduy Unit 3. Results of eddy current inspection on the steam generator of Unit 5 and quantity of the deposits on the surfaces of steam generator during 1989-2001 inspections are given. (uke)

  15. Determination of parameters of the environment for qualification of equipment of the Dukovany NPP. Post-accident parameters in the hermetic zone of Unit 1 for an accident associated with steam line rupture. Rev. 2

    International Nuclear Information System (INIS)

    The thermal hydraulic parameters of the environment (pressure, temperature, relative humidity and water level on the floor) in the hermetic zone of the Dukovany NPP were analyzed for an accident associated with a steam line rupture in the hermetic zone. First, the behavior of the primary and secondary circuits during the accident was analyzed by the RELAP code, and based on the outflow curves for the leak from the steam line so obtained, the response of the hermetic compartments was analyzed by the MELCOR code. The accident was found to proceed fast, so that in half an hour the thermal hydraulic situation is relatively stabilized. The results are compared with those contained in the Preliminary Safety Report and the differences are discussed

  16. Belene NPP - main approaches in the construction organisation

    International Nuclear Information System (INIS)

    Technical planning for the construction of two units at the Belene NPP is presented. Detailed scheme for the assembling of the containment is given, taking into account the capacity of cranes. For the construction of NPP Belene it is possible to use the existing on-site construction 50 tons cranes, as well as mobile crawler cranes with increased lifting capacity. A timetable for the construction is developed. A shortening of the construction time is possible with 4 months. Improvements of the construction process are suggested including use of ready pipe and equipment modules, automated welding, use of advanced technologies for isolation and concreting, organising and control of the technological processes, use of 3D and 6D modeling etc. The recommended improvements can shorten the construction period to 5-5.5 years

  17. Seismic safety of building structures of NPP Kozloduy III

    International Nuclear Information System (INIS)

    In the proposed paper is presented a general summary of the analyses carried out to evaluate the dynamic behavior and to assess the seismic safety of some safety related building structures of NPP Kozloduy. The design seismic loads for the site of Kozloduy NPP has been reevaluated and increased during and after the construction of investigated Units 5 and 6. Deterministic and probabilistic approaches are applied to assess the seismic vulnerability of the investigated structures, taking into account the newly defined seismic excitations. The presented results show sufficient seismic safety for the studied critical structures and good efficiency of the seismic upgrading. The applicability of the investigated structures at sites with some higher seismic activities is discussed. The presented study is dealing mainly with the civil structures of the Reactor building, Turbine hall, Diesel Generator Station and Water Intake Structure. (authors)

  18. Reactor building seismic analysis of a PWR type - NPP

    International Nuclear Information System (INIS)

    Earthquake engineering studies raised up in Brazil during design licensing and construction phases of Almirante Alvaro Alberto NPP, units 1 and 2. State of art of soil - structure interaction analysis with particular reference to the impedance function calculation analysis with particular reference to the impedance function calculation of a group of pile is presented in this M.Sc. Dissertation, as an example the reactor building dynamic response of a 1325 MWe NPP PWR type is calculated. The reactor building is supported by a pile foundation with 2002 end bearing piles. Upper and lower bound soil parameters are considered in order to observe their influence on dynamic response of structure. Dynamic response distribution on pile heads show pile-soil-pile interaction effects. (author)

  19. Some specific features of NPP Paks fuel utilization

    International Nuclear Information System (INIS)

    In this presentation some special and interesting aspects of Paks NPP fuel application are shown. Nearly 100s of fuel assemblies were used in different cycles of Paks NPP units after short or long resting time in the spent fuel pond. The reloading in some cases contained large number of assemblies cooled 6-10 years before reusing. Large deviation of measured and calculated neutron-physical parameters was experienced in some cases. The reason of this effect was investigated. Calculations showed that a part of deviation could be eliminated if we calculate more actinides explicitly in the refuelling design code. This presentation also shows the general experiences of such fuel application. Assemblies could be operated in reliable way keeping the assembly burnup limit

  20. Specific problems in Kozloduy municipality, concerning NPP operation and decommissioning

    International Nuclear Information System (INIS)

    The only nuclear power plant in Bulgaria, which operates for 25 years is located in Kozloduy. Kozloduy municipality is situated in the northern part of Danube plane, includes the administrative center and four villages. It is 200 km far from Sofia and 80 km from the regional center Vratza. The Kozloduy NPP operates 6 units of total capacity 3760 MW, producing more than 40% of the electricity needs in Bulgaria. Settled and recurring problems of the municipality are related to economic, geographical, demographic and administration issues. Future problems will be related to forthcoming reactor shutdown and decommissioning. This involves economic problems, possible bankruptcies of local firms servicing the NPP, decreasing budget and living standard, expected restrictions of social programs, increasing unemployment, possible changes in demographic structure of population

  1. 'Kozloduy' NPP geological environment as a barrier against radionuclide migration

    International Nuclear Information System (INIS)

    The aim of this report is to present an analysis of the geological settings along Kozloduy NPP area from the viewpoint of a natural, protective barrier against unacceptable radionuclides migration in the environment. Possible sources of such migration could be an eventual accident in an active nuclear plant; radioactive releases from decommissioned Power Units or from temporary or permanent radioactive waste repositories. The report is directed mainly to the last case, and especially to the site selection for near surface short lived low and intermediate level (LILW) radioactive repository. The main conclusion of the geological settings assessment and of the many years monitoring is that the Kozloduy NPP area offers good possibilities for site selection of LILW repository. (author)

  2. Simulator training and human factor reliability in Kozloduy NPP, Bulgaria

    International Nuclear Information System (INIS)

    This is a PowerPoint presentation. Situated in North Bulgaria, in the vicinity of the town of Kozloduy, near the Danube River bank, there is the Bulgarian Kozloduy Nuclear Power plant operating four WWER-440 and two WWER-1000 units. Units 1 and 2 were commissioned in July, 1974 and November, 1975, respectively. These were shut down at the end of 2003. Units 3 and 4 were commissioned in December, 1980 and May, 1982. They were shut down at the end of 2006 as a precondition for Bulgaria's accession to the European Union. The 1000 MW units 5 and 6 of Kozloduy NPP were commissioned in September, 1988 and December, 1993, respectively. Large-scale modernization have been implemented and now the units meet all international safety standards. The paper describes the multifunctional simulator Kozloduy NPP for the operational staff training. The training stages are as follows: - Preparatory; -Theoretical studies; - Training at the Training Centre by means of technical devices; - Preparation and sitting for an exam before a Kozloduy NPP expert commission; - Simulator training ; - Preparation to obtain a permit for a license, corresponding to the position to begin work at the NPP; - Exams before the Nuclear Regulatory Agency (NRA) and licensing; - Shadow training at the working place; - Permission for unaided operation. The following positions are addressed by the simulator training: - Chief Plant Supervisor; - Shift Unit Supervisor; - Senior Reactor Operator; - Simulator Instructor; - Controller physicist; -Senior Turbine Operator; - Senior Operator of Turbine Feedwater Pumps of Kozloduy NPP. Improving of training method led to a reduction of number of significant events while worldwide practice proves that improvement of engineering resulted in an increase in the percentage of events, related to human factor. Analysis of human reliability in 2005 and 2006 in cooperation with representatives from Great Britain and the Technical University in Sofia were worked on the DTI NSP B

  3. Methodical recommendations for power unit comprehensive engineering and radiation survey

    International Nuclear Information System (INIS)

    The article describes power unit radiation survey methods developed and applied during conduction of Ch NPP unit I Comprehensive Engineering Radiation Survey. Special requirements for units under decommissioning, main survey principals, criteria for definition of volume and the order of survey for various systems of a NPP Unit are included

  4. Mobile stand for testing charging machine ram devices

    International Nuclear Information System (INIS)

    The equipment described is designed to functional testing of the charging machine (CM) end, in laboratory or NPP conditions, over the span of maintenance activities. It appears to be a portable panel that can be easily coupled to the regulation and control elements of the ram driving systems. Such an equipment occurred as necessary following the analyses of the results and technical problems issued from the technical assistance services which INR Pitesti performed for Cernavoda NPP in the period 1996-1999. The experience acquired from these works resulted in a new design and execution of the CM ram devices the characteristics of which are indicated. The equipment was certified and is now successfully utilized at INR Pitesti and Cernavoda NPP Unit 1. The mobile stand will be used in the near future for testing operations of the CM ends number 4 and 5 destined to Cernavoda NPP Unit 2, planned for year 2002

  5. Barsebaeck NPP in Sweden - Decommissioning Project

    International Nuclear Information System (INIS)

    Barsebaeck 1 and 2, type BWR (Boiling Water Reactor) with a capacity of 615 MWe was closed down permanently on 30 November 1999 respective 31 May 2005 due to political decision. Both units together have been in Service operation (Care and maintenance) since 1 December 2006. Barsebaeck NPP will stay in Service operation until beginning of 2018 when Dismantling operation begins with the aim of a free-realized site in the beginning of 2025. That means that the remaining buildings, including equipment should be declared free-released or dismantled. It would then be up to the owner, E.ON Kaernkraft Sverige AB (EKS) to decide what is to be done with the site in the future. There was a re-organisation at Barsebaeck Kraft AB (BKAB) in 1 January 2007 and the company is organised in the following areas of function: site service operation, decommissioning planning, new business and BO replacement. The Organisation at BKAB has gone down from 450 during operation of Barsebaeck 1 and 2 to 50 employees (2009-01-01) involved in Service operation of both units. But still there are in total 250 persons placed at Barsebaeck NPP with different kinds of job assignments. A lot of activities have been carried out since 2000 and up to now for example: - All nuclear fuel has been transported away to interim storage at CLAB in Oskarshamn. - BKAB have built up contact nets and competence by taking part in different kinds of national and international organisations (SKB, IAEA, OECD/NEA TAG, WNA, ENISS, WANO, EPRI etc) commissions. - The Electrical and operational systems have been rebuilt for the actual demands and requirements for the Service operation. - The central control room is unattended since 17 December 2007 and the supervision of the Service operation is handled by a system of VDI (duty engineers) and LOP (alarm operators). - Full system decontamination on unit 1 and 2. Barsebaeck's approach today and for the future dismantling are: - Safer; - Faster; - Cost effective. BKAB

  6. Experience of Bohunice V-1 NPP

    International Nuclear Information System (INIS)

    Slovakia remains significantly dependent on imports of primary energy sources, which represent as much as 80% of the demand. Of the total consumption of electricity in Slovakia, 40% was generated in nuclear power plant units in 1998. Slovakia operates 6 units with WWER 440 nuclear reactors. Slovakia is the signatory of all important international agreements and conventions in the field of nuclear energy, and its legislation is in an advanced stage of approximation to European Union law. This is a very important aspect, showing Slovakia's approach to nuclear safety. In 1993 Slovakia accepted the commitments of the UN Convention on Climate Changes, including a reduction of greenhouse gases to 1990 levels by the year 2000. Moreover, as an internal target Slovakia has set the reaching of the 'Toronto Objective', i.e. 20% reduction in COx, emissions through the year 2005 as compared to 1988. In our opinion, this is not possible without nuclear energy. Time has shown, that the political aspects are more powerful, especially if you underestimate their importance over the than the technical ones. In the case of Bohunice V-1 NPP the political aspects were on the following levels: 1. Slovak republic (Czechoslovakia), political changes, decisions of the government; 2. European Union - Agenda 2000, Accession criteria, nuclear safety criteria, EBRD; 3. Austria as a neighbouring country. Starting with year 1990, 23 expert missions took place at Bohunice V-1 NPP by now. The only criteria for further operation should have been Nuclear safety, which is supervised by NRA SR. It was fully in compliance with EU policy, each country is solely responsible for its energy sector and for nuclear energy use. Our satisfaction lasted not too long. Following negotiation with EU on the highest political level, driven by willingness to be invited for negotiation of accession on the Helsinki Summit, the Slovak government decided on September 14th, on Bohunice V-1 Units shutdown in 2006 and 2008

  7. Emergency preparedness at Barsebaeck NPP in Sweden

    International Nuclear Information System (INIS)

    On-site emergency preparedness plan at Barsebaeck NPP is presented. In an emergency the responsibility of the NPP is to alarm the emergency organizations, spend all efforts to restore safe operation, assess the potential source term as to size and time, protect their own personnel, inform personnel and public. Detailed emergency procedures overview is provided

  8. Safety culture in Ignalina NPP, regulatory view

    International Nuclear Information System (INIS)

    The presentation describes how success on the way to a high level Safety Culture in Ignalina NPP may be achieved by daily, well motivated activities with good attitude and proper management participation, ensuring the development and proper implementation of Safety Culture principles within the activities of Operational organization of Ignalina NPP

  9. VMEbus technology in NPP control automation

    International Nuclear Information System (INIS)

    In frames of SPAS project (system for emergency situations and accident prevention at NPPs in Ukraine) a series of developments was made to increase the efficiency and control of NPP equipment and main technological processes. They are based on information which is permanently renewed and accumulated in regular NPP system. Technical parameters of this system are described

  10. Psychological methods as applied to NPP personnel

    International Nuclear Information System (INIS)

    Psychologists' experience in nuclear power personnel work system is described. Possibilities of practical application of scientific information, ways and methods collected in psychology, their effect when solving problems on profession orientation, personnel selection, arrangement, training and education, are shown. Necessity to take into account personnel psychological data under conditions of increased hazard of work at NPP is illustrated taking Chernobyl NPP as an example

  11. Seismic characterization of the NPP Krsko site

    International Nuclear Information System (INIS)

    The goal of NPP Krsko PSA Project Update was the inclusion of plant changes (i.e. configuration/operational related) through the period January 1, 1993 till the OUTAGE99 (April 1999) into the integrated Internal/External Level 1/Level 2 NPP Krsko PSA RISK SPECTRUM model. NPP Krsko is located on seismotectonic plate. Highest earthquake was recorded in 1917 with magnitude 5.8 at a distance of 7-9 km. Site (founded) on Pliocene sediments which are as deep as several hundred meters. No surface faulting at the Krsko site has been observed and thus it is not to be expected. NPP Krsko is equipped with seismic instrumentation, which allows it to complete OBE (SSE). The seismic PSA successfully showed high seismic margin at Krsko plant. NPP Krsko seismic design is based on US regulations and standards

  12. NPP lifetime philosophy: the transatlantic difference

    International Nuclear Information System (INIS)

    Fundamental institutional and cultural differences in the transatlantic nuclear power industries, and in particular those between the Nordic countries and the United States, have driven divergent plant life management strategies -strategies resulting in distinctly different plant performance. Recognition of the linkage between three key components of overall Nuclear Power Plant (NPP) performance - yearly O and M costs, safety, and effective plant lifetime -is based on different institutional perspectives. In the Nordic countries, explicit recognition of this linkage has been historically translated into an integrated approach to plant performance. American NPPs, however, have been forced to focus primarily on near term O and M performance and regulatory mandated investment. While Nordic NPPs view capital investment in plant lifetime management and modernization as necessary to avoid declining plant performance and the cost of replacement power, American NPPs exhibit reluctance for such investments due to the difficulty of justifying the associated short-term costs. The diverging histories of two NPPs of the same vintage and design, one in Sweden and one in the United States, exemplify the potential ramifications of these approaches. The Swedish plant continues to operate with excellent performance indicators, while undertaking a comprehensive and long-term modernization program. The American facility is likely to be decommissioned due to unsustainable economic performance. (author)

  13. Co-operation between SiP and the Ignalina NPP: Ongoing Projects to be Continued, Consideration Is Taken of Present-day Needs

    International Nuclear Information System (INIS)

    Discussions of Ignalina NPP and Swedish International Project Nuclear Safety (SiP) on the implementation of the projects financed by the Swedish Government are presented. In 2000 Government of Sweden has given 10 M SEK to Ignalina NPP to the issues related with decommissioning of Unit 1

  14. Reliability analysis of protection systems in NPP applying fault-tree analysis method

    International Nuclear Information System (INIS)

    This paper demonstrates the applicability and limits of dependability analysis in nuclear power plants (NPPS) based on the reactor protection refurbishment project (RRP) in NPP Paks. This paper illustrates case studies from the reliability analysis for NPP Paks. It also investigates the solutions for the connection between the data acquisition and subsystem control units (TSs) and the voter units (VTs), it analyzes the influence of the voting in the VT computer level, it studies the effects of the testing procedures to the dependability parameters. (author)

  15. The decommissioning NPP A-1

    International Nuclear Information System (INIS)

    Project of decommissioning NPP A-1 is split into 4 main groups of tasks. Tasks in group 1 are focused on the solution of selected problems that have immediate impact on the environment. It is mainly the solution of problems in the building of cleaning station of wastage water and in the building with underground storage tanks for wastage water and solid radwaste, including the prevention of wash-out and penetration of contaminated soil from these buildings into surface and underground waters. A part of addressing these tasks is a controlled of generated radwaste-predominatly sludge with various physical and chemical properties. Tasks in group 2- following the removal of spent fuel-are focused on the management of all radwaste in the long-term storage facility, in the short-term storage facility, equipment of transport and technology part, equipment in hot cells. Tasks in group 3 are focused on development of technology procedures for treatment and conditioning of sludge, contaminated soils and concrete crush, saturated ionexes and ash from incineration facility of the Bohunice radwaste treatment and conditioning complex. Tasks in group 4 are focused on the methodology. And technical support for particular activities applicable during decommissioning NPP

  16. Operating Experience at NPP Krsko

    International Nuclear Information System (INIS)

    Systematic analysis of operational experience by assessment of internal and industry events and the feedback of lessons learned is one of the essential activities in the improvement of the operational safety and reliability of the nuclear power plant. At NPP Krsko we have developed a document called ''Operating Experience Assessment Program''. Its purpose is to establish administrative guidance for the processing of operating events including on-site and industry events. Assessment of internal events is based on the following methods: Event and Causal Factor Charting, Change Analysis, Barrier Analysis, MORT (Management Oversight and Risk Tree Analysis) and Human Performance Evaluation. The operating experience group has developed a sophisticated program entitled ''Operating experience tracking system'' (OETS) in response to the need for a more efficient way of processing internal and industry operating experience information. The Operating Experience Tracking System is used to initiate and track operational events including recommended actions follow up. Six screens of the system contain diverse essential information which allows tracking of operational events and enables different kinds of browsing. OETS is a part of the NPP Krsko nuclear network system and can be easily accessed by all plant personnel. (author)

  17. Corrosion products in the secondary circuit of Beznau NPP

    International Nuclear Information System (INIS)

    The Beznau NPP consists of two 2-loop 380 MWe pressurized water reactors. Unit 1 went into operation in 1969, unit 2 in 1971. Regarding its age, Beznau has to be designated as an old plant. But in fact one has to talk of two young, 'state of the art' units, taking into account the numerous back-fittings. Important measures were the replacements of the steam generators (SGR) realized at unit 1 in 1993 and at unit 2 in 1999. But there were more changes in the secondary systems. Copper was banished from the system completely and replaced by stainless and chromium steel. The condensers were fitted with titanium tubes. New SG with tubes from Inconel 690 TT were installed. Of course the water chemistry was also influenced by these changes. (N.T.)

  18. The Service Life Evaluation for Concrete Structure of NPP

    International Nuclear Information System (INIS)

    Prolonged exposure to the marine environment degrades the durability of concrete and shortens the service life of concrete due to degradation factors such as chloride, carbonation, freezing and thawing, sulfate. Therefore, many country's organizations like the Korea Concrete Institute (KCI), the American Concrete Institute (ACI), the International Federation for Structural Concrete (FIB), the American Society for Testing and Material (ASTM) which recognized the seriousness of this deterioration proposed equation models to evaluate the service life for the concrete structures. As a result, this paper is to especially consider the service life evaluation using these equation models for concrete structure of NPP in Korea compared with 60 years as a design service life. The concrete durability evaluation for Shin-Hanul NPP units 1 and 2 is carried out by using typically proposed assessment models in domestic and foreign standard. It is confirmed that the service life of concrete durability for each of deterioration factors is significantly higher than 60 years as a design service life. As a result, the study of combined deterioration for the concrete structures of NPP in future is positively necessary and maintenance control through regular monitoring should be conducted to secure safety margin basis

  19. Novel technology for hydrothermal treatment of NPP evaporator concentrates

    International Nuclear Information System (INIS)

    A novel technology was developed for treatment of evaporator concentrates produced as a result of operation of evaporation devices comprising the main component of special water purification systems of nuclear power plants (NPP). The developed technology includes a hydrothermal (T=250-300 deg. C and P=80-120 bar) processing of evaporator concentrates in oxidation medium in order to destruct stable organic complexes of cobalt radionuclides and remove these radionuclides by oxide materials formed during such a processing. The cesium radionuclides contained in evaporator concentrates are removed by a conventional method-through application of one of the developed composite sorbents with ferrocyanides of transition metals used as active agents. Extensive laboratory studies of the processes occurring in evaporator concentrates under hydrothermal conditions were performed. It was shown that hydrothermal oxidation of evaporator concentrates has a number of advantages as compared to traditional oxidation methods (ozonization, photo-catalytic, electrochemical and plasma oxidation). A laboratory installation was built for the flow-type hydrothermal oxidation of NPP evaporator concentrates. The obtained experimental results showed good prospects for the developed method application. On the basis of the results obtained, a pilot installation of productivity up to 15 l/hour was developed and built in order to work out the technology of evaporator concentrates hydrothermal treatment. The pilot tests of the hydrothermal technology for evaporator concentrates hydrothermal treatment were performed for 6 months in 2006 at the 1. reactor unit of the Novovoronezhskaya NPP (Voronezh Region, Russia). Optimal technological regimes were determined, and estimations of the economic soundness of the technology were made. The advantages of the presented technology in terms of management of concentrated liquid radioactive wastes (LRW) at nuclear cycle facilities, as compared to other methods

  20. Electrical Grid Conditioning For First NPP Integration, a Systems Engineering Approach Incorporating Quality Function Deployment

    International Nuclear Information System (INIS)

    Nuclear power plant has a high potential to cause serious harm to environment as evidenced by effects of Fukushima and Chernobyl accidents. A reliable electrical power is required for a NPP to facilitate cooling after a shutdown. Failure of electrical power supply during shutdown increases core damage probability. Research shows that a total of 39% of LOOP related events in US are electrical grid centered. In Korea, 38% and 29% of all events that led to NPP shutdown at Hanul units 3-6 and at Hanbit units 3-6 respectively were electrical related. Electric grids for both operating and new NPPs must therefore be examined and upgraded for reliability improvement in order to enhance NPP safety

  1. Radioecological problems of NPP reservoirs-coolers

    International Nuclear Information System (INIS)

    Radioecological problems of NPP reservoir-coolers are considered in connection with thermal effluents and partly radiactive wastes. It is shown that one of real means to reduce undesirable ecological consequences of surplus heat release into the medium is the usage of NPP heated waters in energy-biological and agro-industrial complexes. In case of NPP operation the normalized environmental disposal of a number of radionuclides is specified. In this connection the necessity is pointed out to establish a list of the most dangerous radionuclides to be discharged into water medium by various NPP types, to study their behaviour in main water reservoir components; to determine coefficients of radionuclides accumulation in organisms related to human food chain. Actual is the problem of biological effects which can arise in hydrocenoses of reservoir-coolers as a result of long-term or chronic action of NPP radioactive waste disposal. A wide program of ecological investigations is laid down related to the problem of using NPP water thermal effluents and radioecology of reservoirs-coolers, the realization of the program being initiated in the vicinity of the Beloyarsk NPP

  2. Liquid relief valves - PHTS overpressure protection and threat for loss of heavy water in a CANDU 6 NPP

    International Nuclear Information System (INIS)

    pumps) to be sure that the reactor power reduction will happen. There are more reactor trip parameters that lead to the reactor power reduction after LRV's opening but they do not cover all events. To cover with reactor trip parameters the event of one LRV spurious opening and based on AECL studies, for Cernavoda Unit 2 some operator actions have been proposed to be implemented in order to decrease the ROH operating pressure setpoint and to reduce reactor power on a degassing condenser pressure signal. These are operator actions and they are not credited in a nuclear safety analysis in the first 15 minutes after initiating event. So, the mentioned operator actions should be changed in automatic actions to avoid the loss of heavy water into containment in this event case. - Maintaining an adequate PHTS mass inventory balance during all NPP's conditions, including the events described above, is the main objective to sustain the fuel cooling. As well, there are some event scenarios that challenge PIC system and that may even override its capacity. Taking into account that at 10.34 MPa(a) three automatic simultaneous corrective actions will be accomplished, namely LRV's opening, stepback function and SDS-1 initiation, it seems to be appropriate if, for instance, the stepback function would be initiated prior to this setpoint. More detailed and realistic studies on this approach should be made in order to assess the efficiency of an earlier stepback on ROH pressure, or a stepback or setback on degassing condenser high pressure or high level. - Instrument air and power supply must be assured in any kind of conditions in order to reduce as much as possible the probability to have a LRV spurious opening. (authors)

  3. ESTE EMO and ESTE EBO - emergency response system for NPP Mochovce and NPP Bohunice V-2

    International Nuclear Information System (INIS)

    Programs ESTE EMO and ESTE EBO are emergency response systems that help the crisis staff of the NPP in assessing the source term (predicted possible release of radionuclides to the atmosphere ), in assessing the urgent protective measures and sectors under threat, in assessing real release (symptoms of release really detected and observed), in calculating radiological impacts of real release, averted or avertable doses, potential doses and doses during transport or evacuation on specified routes. Both systems serve as instruments in case of severe accident (DBA or BDBA) at NPP Mochovce or NPP Bohunice, accidents with threat of release of radioactivity to the atmosphere. Systems are implemented at emergency centre of Mochovce NPP and Bohunice NPP and connected online to the sources of technological and radiological data from the reactor, primary circuit, confinement, secondary circuit, ventilation stack, from the area of NPP (TDS 1) and from the emergency planning zone (TDS 11). Systems are connected online to the sources of meteorological data, too. (authors)

  4. Improved technical specifications for Korean NPP

    International Nuclear Information System (INIS)

    PWRs use Technical Specifications(Tech. Spec.) to ensure safe operation of the plant. Recently, many efforts were made to improve Tech. Spec. and as a result, Improved Standard Technical Specifications(ISTS) have been developed. Korean NPP technical specifications were converted to ISTS format. KAERI also provided supporting documents for technical specification conversion including mark-up's and description of changes. This paper describes and summarizes the results of implementation of ISTS for Korean NPP. The new Tech. Spec. will improve safety of Korean NPP

  5. Analysis on the effect of local content to the economic aspect of NPP

    International Nuclear Information System (INIS)

    Study analysis on the effect of local content to the economic aspect of NPP has already been conducted. This scope of study covers: NPP technology system analysis (OPR-1000), national industry capability to participate in NPP construction and effect analysis toward the economic. Economic analysis is conducted for 2 units NPP OPR-1000. This study concludes that: (1) The level of local content for the first 2 units NPP in Indonesia about 35.34% (pessimistic case) and 43.38% (optimistic case). (2) To reach the local content government support is needed, i.e. policy of industry, particularly the police related to technology transfer. (3) The total generation cost that could be saved per year in pessimistic case is around US$ 14.55 million - US$ 14.57 million and in optimistic case it is around US$ 22.23 million – US$ 22.26 million. (4) The local content implementation will provide decreasing of generation cost about 1.75% up to 1.76% in pessimistic case, and around 2.67% up to 2.68% in optimistic case. (author)

  6. Development of the learning-training lessons for functional-analytical training facility of NPP with WWER-1000 reactor

    International Nuclear Information System (INIS)

    General principles of construction of functional-analytical training facility of a NPP, which represents the computation system consisting of the ES-1045 type computer and personal computers, are considered. The KIPR program used for the ES computer describes stationary and dynamic regimes of a power unit real time operation. The personal computers perform service functions of displaying the information required by an operator. The high efficiency of the algorithms used for NPP operator training is proved

  7. Trial operation of TVS-2 at Balakovo NPP. Analysis of results and further modernization

    International Nuclear Information System (INIS)

    In this report the more detailed specifications of TVS-2 considering modifications of separate units, and also the conditions and results of its operation at Balakovo NPP on the basis of three fuel loads are presented. Implementation of TVS-2 at power units of Balakovo NPP in the fuel cycle 3x350 eff. days has been started in 2003 and the reactor core full loading at Balakovo NPP, Unit 1 has been achieved in 2005. Considering positive operational experience of TVS-2 at Unit 1 implementation of TVS-2 by full make-ups has been started at other units of Balakovo NPP. The operational results confirm the predicted essential increasement in reliability of reactor scram, possibility of implementation of new design restrictions, which enable to form the fuel loading with small neutron leakage. Besides, the favorable results on performance of transport - technological procedures enabling to reduce time of PM has been obtained. On the basis of this structure the detailed project report of a new FA modification with lengthened fuel stack has been developed, the necessary calculational and experimental justifications have been performed, materials for obtaining a license to trial operation of the first lot of such fuel assemblies beginning from 2006 are being prepared

  8. A brief overview of Ignalina NPP safety issues

    International Nuclear Information System (INIS)

    A description of the safety of Ignalina NPP in a very popular form is presented. Answers to the most frequently recurring questions concerning the Ignalina NPP are provided based on recently completed international studies. Questions are like these: can a similar accident to the one that occurred in Chernobyl take place at Ignalina NPP, does the Ignalina NPP have a containment, what are the probabilities and potential consequences of accidents, etc. The brochure contains a short description of Ignalina NPP safety improvement programs

  9. Suomi NPP VIIRS Imagery evaluation

    Science.gov (United States)

    Hillger, Donald; Seaman, Curtis; Liang, Calvin; Miller, Steven; Lindsey, Daniel; Kopp, Thomas

    2014-06-01

    The Visible Infrared Imaging Radiometer Suite (VIIRS) combines the best aspects of both civilian and military heritage instrumentation. VIIRS has improved capabilities over its predecessors: a wider swath width and much higher spatial resolution at swath edge. The VIIRS day-night band (DNB) is sensitive to very low levels of visible light and is capable of detecting low clouds, land surface features, and sea ice at night, in addition to light emissions from both man-made and natural sources. Imagery from the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite has been in the checkout process since its launch on 28 October 2011. The ongoing evaluation of VIIRS Imagery helped resolve several imagery-related issues, including missing radiance measurements. In particular, near-constant contrast imagery, derived from the DNB, had a large number of issues to overcome, including numerous missing or blank-fill images and a stray light leakage problem that was only recently resolved via software fixes. In spite of various sensor issues, the VIIRS DNB has added tremendous operational and research value to Suomi NPP. Remarkably, it has been discovered to be sensitive enough to identify clouds even in very low light new moon conditions, using reflected light from the Earth's airglow layer. Impressive examples of the multispectral imaging capabilities are shown to demonstrate its applications for a wide range of operational users. Future members of the Joint Polar Satellite System constellation will also carry and extend the use of VIIRS. Imagery evaluation will continue with these satellites to ensure the quality of imagery for end users.

  10. Krsko NPP radioactive waste characteristics

    International Nuclear Information System (INIS)

    In May 2005 Krsko NPP initiated the Radioactive Waste Characterization Project and commissioned its realization to the consulting company Enconet International, Zagreb. The Agency for Radwaste Management was invited to participate on the Project. The Project was successfully closed out in August 2006. The main Project goal consisted of systematization the existing and gathering the missing radiological, chemical, physical, mechanical, thermal and biological information and data on radioactive waste. In a general perspective, the Project may also be considered as a part of broader scope of activities to support state efforts to find a disposal solution for radioactive waste in Slovenia. The operational low and intermediate level radioactive waste has been structured into 6 waste streams that contain evaporator concentrates and tank sludges, spent ion resins, spent filters, compressible and non-compressible waste as well as specific waste. For each of mentioned waste streams, process schemes have been developed including raw waste, treatment and conditioning technologies, waste forms, containers and waste packages. In the paper the main results of the Characterization Project will be briefly described. The results will indicate that there are 17 different types of raw waste that have been processed by applying 9 treatment/conditioning technologies. By this way 18 different waste forms have been produced and stored into 3 types of containers. Within each type of container several combinations should be distinguished. Considering all of this, there are 34 different types of waste packages altogether that are currently stored in the Solid Radwaste Storage Facility at the Krsko NPP site. Because of these findings a new identification system has been recommended and consequently the improvement of the existing database on radioactive waste has been proposed. The potential areas of further in depth characterization are indicated. In the paper a brief description on the

  11. Intranet portal at the Krsko NPP, Slovenia

    International Nuclear Information System (INIS)

    The intranet portal (named IntraNEK) at Krsko NPP serves as a single entry point to access the internet and various plant applications and links. The front page consists of the standard internet search bar and links to various applications that can either reside within the technological computer network (TRM) or within the plant business computer network. Access to the TRM applications is read only. Some applications on the business computer network are open to all personnel who log on to the network while some applications are restricted and secured, and require additional login entries. A selected link will open in a new window. Documents will open with the appropriate software tool depending on the document file format. Some categories of documents are available in image form only (e.g. procedures, drawings etc.), while some are available in fully searchable PDF format (e.g. technical specifications, updated safety analysis reports (USARs) etc.). Plant departments (organizational units) have their own pages accessible from the front page. Their pages contain links to their own information resources or links to other resources and applications, tailored to the department needs. During recent years a number of web based applications have been developed that are connected also with a common Oracle database. Some are designed to serve for data entry and browsing while others serve for browsing only

  12. LILW management in Paks NPP 2004

    International Nuclear Information System (INIS)

    Waste classification, sources, volumes, composition and treatment of different (liquid and solid) wastes in Paks are presented. The pretreatment of the liquid waste includes Collection in tanks, decanting, filtration (ion exchange resins), chemical treatment, evaporation, condensate cleaning and discharging, radioactive liquid wastes storage. Yearly accumulated volume of liquid wastes is approximately 250 m3; evaporation residues - 3644 m3 used ion exchange resins - 39.1 m3, and acidising solutions of evaporator - 190 m3. The free storage capacity for liquids is sufficient for 1-2 years, so 3800 m3 new capacities are under construction. The volume reduction technology used in Paks NPP is also presented in the paper. It is stated that the solidification will only be started after constructing the final disposal facility. The main steps of low and intermediate level solid wastes treatment are: selective collection, transport in the controlled area, pre-qualification (potentially exemptible or not), assorting, compaction by 50t compactor, wastes qualification, interim storage. The volume of solid wastes yearly is 600 - 1000 pcs. New elements in the concept for the low and intermediate level wastes are added after the fuel damage at unit 2 such as: additional interim storage capacities (3800 m3) for liquids (under construction); TRU separation (if needed); supercompaction technology and others because of new waste acceptance criteria under generation

  13. Nuclear power in Romania - present and future

    International Nuclear Information System (INIS)

    The paper presents the actual status of nuclear power in Romania, with one CANDU 6 unit in operation (Cernavoda Unit 1) and second unit under construction (Cernavoda Unit 2). The Cernavoda Unit 1 operation performance had an important role for the next unit completion by the Romanian nuclear utility, NUCLEARELECTRICA, together with the traditional partners in the management of the project, AECL Canada and ANSALDO Italy. Cernavoda Unit 2 status showed that 2005 is a very important year for this project, which shall start its commercial operation in March 2007. The Romanian Government plays and important role in the development of nuclear power and the energy strategy contains directions for further development of Cernavoda NPP. Starting with 2003, NUCLEARELECTRICA worked on the pre-feasibility study of Cernavoda Unit 3. Based on the private participation for the financing of this project there are potential investors which expect the results of the market and feasibility studies planned to be finalized by the end of 2005. The Project Company responsible for Cernavoda Unit 3 is planned to be registered in Romania by July 2006. The necessary commercial contracts and financing are to be concluded by March 2007, when the progress works on the site will be restarted. Based on this national nuclear power, Romania shall provide security of electricity supply and assure flexibility, by optimum utilization of the hydro, coal, nuclear and others natural and renewable resources. (author)

  14. Sensitivity of Input Parameters in the PSHA for NPP Sites

    International Nuclear Information System (INIS)

    In this study, the most uncertain input parameter in the PSHA was identified for Korean NPP sites through sensitivity analysis. Shinuljin Nuclear Units 1 and 2 site was selected in this study. Expert panels developed input parameters for PSHA. Input data were analyzed, and used for sensitivity analysis to see the effects of each parameter on seismic hazard. Through sensitivity analysis, we identified the degree of uncertainty of each parameter. The CONPAS, EQHAZAS, and EQHAZAS Manager codes, which were developed by KAERI, were utilized to compute the seismic hazard. The Gutenberg-Richter parameter was identified as the most uncertain one in this study

  15. Status of steam generator tubing integrity at Jaslovske Bohunice NPP

    Energy Technology Data Exchange (ETDEWEB)

    Cepcek, S. [Nuclear Regulatory Authority of the Slovak Republic, Trnava (Slovakia)

    1997-02-01

    Steam generator represents one of the most important component of nuclear power plants. Especially, loss of tubing integrity of steam generators can lead to the primary coolant leak to secondary circuit and in worse cases to the unit shut down or to the PTS events occurrence. Therefore, to ensure the steam generator tubing integrity and the current knowledge about tube degradation propagation and development is of the highest importance. In this paper the present status of steam generator tubing integrity in operated NPP in Slovak Republic is presented.

  16. R and D Activities for NPP Life Management in Korea

    International Nuclear Information System (INIS)

    Many R and D activities related to PLiM have been carried out and implemented to Korean NPP for the long term operation. Those activities include ageing management study, periodic safety review, steam generator management programme, materials reliability programme, thinned pipe management programme, study on dissimilar metal welds, etc. Based on the R and D activities, long term operation of Kori Unit 1 was successfully started from January 17, 2008 for next 10 years beyond its original design life. In this paper, all the activities and their results of the R and D programmes are briefly introduced. (author)

  17. Safety improvement programme of Ignalina NPP SIP-2

    International Nuclear Information System (INIS)

    The second large scale safety upgrading programme of Ignalina NPP - SIP-2 which currently is under implementation is described. Based on recommendation made in safety analysis report (SAR), its review (RSR) and recommendations from Ignalina Safety Panel (ISP) programme consists of 158 items and is divided into three parts: modification of systems and equipment, improvement of management and quality assurance system and additional safety analysis. Programme was started in 1997. Some of the projects have to be implemented before licensing of unit No.1 will be finished. Description of the most important and urgent projects is provided

  18. Emergency operating procedures knowledge management for NPP MCR operators' support

    International Nuclear Information System (INIS)

    The described research aims at computerization of handling of the knowledge gathered from emergency operating procedures, which makes it possible to reduce frequency of errors committed by NPP main control room operators when executing the procedures. The mechanism for representation of procedures' declarative knowledge has been proposed. This method is based on two level semantic network hierarchy, namely intensional and extensional levels. The method has been used for a basic development of prototype of computer based procedures intended to support of operators under accidents. The system provides automatic on-line identification of the situation, selection of relevant procedure, its representation at video display unit and tracking of correctness of the procedure execution

  19. R and D status for NPP life management in Korea

    International Nuclear Information System (INIS)

    The economical benefits may be achieved by the plant life management (PLiM) as well as structural integrity of the critical components of NPP. Systems, structures and components (SSC) of NPP are designed to have safety margins in design stage, and being operated with operational margins. As the plant gets older and older, however, aging of SSC occurs and some of SSC may be sometimes failed due to the unexpected aging mechanisms in design stage. Most countries which have operated NPP have their own R and D programs to establish proper countermeasures against the aging and degradation of SSC, The well known program are materials reliability program (MRP) and steam generator management program (SGMP) of EPRI. In Korea, we also have our own R and D programs for the plant life management. In this paper, the present status of the R and D programs will be introduced. Long term operation of a nuclear power plant is one of the goals that the plant wants to achieve, which may be possible as long as the plant safety is maintained and the economical benefits is expected. The economical benefits may be achieved by the plant life management (PLiM) activities. Many R and D activities related to PLiM have been carried out and implemented to Korean NPP, Kori Unit 1 and Wolsong Unit 1 in particular, for the long term operation beyond their original design lives. Those activities include PLiM study, PSR, SGMP, MRP, thinned pipe management program, study on dissimilar metal welds, aging monitor etc. With the results of R and D activities, continued operation of Kori Unit 1 was successfully started from January 17, 2008 for next 10 years beyond its design life. It must be a landmark of 30 years history of nuclear power generation in Korea. Subsequently Wolsong Unit 1 is also expected to start its continued operation when the replacement of pressure tubes and feeders are completed in 2009. Many countries have plans to build new reactors or to extend the life of operating plants.

  20. Maintenance optimization of the Ignalina NPP safety systems

    International Nuclear Information System (INIS)

    This paper represents some theses and mathematical approach to optimization of technical specification problems of the diesel generators system (DGS) at the Ignalina NPP (INPP) in Lithuania. Analysis unites three chapters, each attributed to the solving of related problems: dependency of the Core Damage Frequency (CDF) on DGS test interval (Chapter 2), analysis and comparison of two different maintenance strategies for DGS (Chapter 3), DGS test interval's optimisation (averaged loss function minimisation) taking into consideration maintenance and DGS failure's consequence costs (Chapter 4). The mathematical model was developed which lets to estimate DGS failure probability, the averaged loss function value and study the influence of different parameters into final results. (author)

  1. A risk informed safety classification for a Nordic NPP

    Energy Technology Data Exchange (ETDEWEB)

    Jaenkaelae, K. [Fortum Nuclear Services Ltd. (Finland)

    2002-01-01

    The report describes a study to develop a safety classification proposal or classi- fication recommendations based on risks for selected equipment of a nuclear power plant. The application plant in this work is Loviisa NPP unit 1. The safety classification proposals are to be considered as an exercise in this pilot study and do not necessarily represent final proposals in a real situation. Comparisons to original safety classifications and technical specifications were made. The study concludes that it is possible to change safety classes or safety signifi- cances as considered in technical specifications and in in-service-inspections into both directions without endangering the safety or even by improving the safety. (au)

  2. A risk informed safety classification for a Nordic NPP

    International Nuclear Information System (INIS)

    The report describes a study to develop a safety classification proposal or classi- fication recommendations based on risks for selected equipment of a nuclear power plant. The application plant in this work is Loviisa NPP unit 1. The safety classification proposals are to be considered as an exercise in this pilot study and do not necessarily represent final proposals in a real situation. Comparisons to original safety classifications and technical specifications were made. The study concludes that it is possible to change safety classes or safety signifi- cances as considered in technical specifications and in in-service-inspections into both directions without endangering the safety or even by improving the safety. (au)

  3. Optimizing NPP performance and service life

    International Nuclear Information System (INIS)

    The most effective way for new power production in Ukraine is the completions of the Khmelnitskij 2 and Rovno 4 NPP project. The report presents the financing terms and conditions of the Energoatom corporate bonds issue

  4. Krsko NPP Periodic Safety Review program

    International Nuclear Information System (INIS)

    The need for conducting a Periodic Safety Review for the Krsko NPP has been clearly recognized both by the NEK and the regulator (SNSA). The PSR would be highly desirable both in the light of current trends in safety oversight practices and because of many benefits it is capable to provide. On January 11, 2001 the SNSA issued a decision requesting the Krsko NPP to prepare a program and determine a schedule for the implementation of the program for 'Periodic Safety Review of NPP Krsko'. The program, which is required to be in accordance with the IAEA safety philosophy and with the EU practice, was submitted for the approval to the SNSA by the end of March 2001. The paper summarizes Krsko NPP Periodic Safety Review Program [1] including implemented SNSA and IAEA Expert Mission comments.(author)

  5. Treatment of NPP wastes using vitrification

    International Nuclear Information System (INIS)

    Glass-based materials to immobilize various liquid and solid radioactive wastes generated at nuclear power plants (NPP) were designed. Glassy waste forms can be produced using electric melting including a cold crucible melting. Leach rate of cesium was found to be 10-5-10-6 g/(cm2 day) (IAEA technique). Volume reduction factor after vitrification reached 4-5. Various technologies for NPP waste vitrification were developed. Direct vitrification means feeding of source waste into the melter with formation of glassy waste form to be disposed. Joule heated ceramic melter, and cold crucible were tested. Process variables at treatment of Kursk, Chernobyl (RBMK), Kalinin, Novovoronezh (VVER) NPP wastes were determined. The most promising melter was found to be the cold crucible. Pilot plant based on the cold crucibles has been designed and constructed. Solid burnable NPP wastes are incinerated and slags are incorporated in glass. (author)

  6. Issues of risk management during NPP operation

    International Nuclear Information System (INIS)

    The paper outlines risk management issues during safety assessments of nuclear facilities and summarizes international experience in NPP risk management in different countries. The need is also considered to elaborate risk management and optimization procedures for Ukrainian NPPs

  7. Geological evaluation of the Paks NPP site

    International Nuclear Information System (INIS)

    The geological evaluation of the site of nuclear power plant constitutes the basis for the assessment of seismic hazard important in terms of the NPP safety. Its re-evaluation is imperative because of the new safety requirements and the new scientific knowledge. Geological evaluation of the Paks NPP site is presented in this paper. Based on seismotectonic evaluation and the seismological data, the seismic hazard of the plant site was determined by using both probabilistic and deterministic methods

  8. Training human resource for NPP in Vietnam

    International Nuclear Information System (INIS)

    Vietnam will establish the first NPP in the near future. With us the first important thing is the human resource, but now there is no university in Vietnam training nuclear engineers. In EPU (Electric Power University), now we are preparing for training nuclear engineers. In this paper, we review the nuclear man power and the way to train the high quality human resource for NPP and for other nuclear application in Vietnam. (author)

  9. Ignalina NPP Safety Analysis: Models and Results

    International Nuclear Information System (INIS)

    Research directions, linked to safety assessment of the Ignalina NPP, of the scientific safety analysis group are presented: Thermal-hydraulic analysis of accidents and operational transients; Thermal-hydraulic assessment of Ignalina NPP Accident Localization System and other compartments; Structural analysis of plant components, piping and other parts of Main Circulation Circuit; Assessment of RBMK-1500 reactor core and other. Models and main works carried out last year are described. (author)

  10. Unit shutdown software

    International Nuclear Information System (INIS)

    The paper Unit Shutdown Software contains a description of software which is to be used by the WWER 440 type NPP unit manager during unit shutdown operations. The software enables to display measured or calculated values on the basis of real-time technological process data acquisition, provides advices during unit shutdown and, in the cases when there is a faulty intervention or inception of dangerous situation during the unit shutdown process, produces warnings. (author). 4 figs

  11. Diagnostic system for process control at NPP Dukovany load follow

    International Nuclear Information System (INIS)

    The NPP Dukovany is being operated in the frequency control since 1996. In last year a project for the plant load follow has been developed. One part of the project is to install a diagnostic system for process control. At present the main control loops of the plant control system are regular tested after unit refuelling only. The functionality and control system parameter adjusting is tested by certificated procedures. This state is unsuitable in view of the plan load follow operation. The relevant operational modes are based on minimisation of influence on plant component life time and on achievement of planned unit parameters. Therefore it is necessary to provide testing of main control system parts in shorter time period. Mainly at time when the unit is really in load follow operation. The paper describes the diagnostic system for process control which will be at NPP Dukovany implemented. The principal of the system will be evaluation of real and expected changes of technological variables. The system utilises thermohydraulic relation among main technological variables and relation among controlled and manipulated variables. Outputs of the system will be used to operational staff support at the plant operation. It enables: determination of control system state, estimation and check of future control system state, early indication of the deviation of process from normal conditions, check of efficiency of operational staff intervention into plant control. The system gives the plant operator new information for the plant process control. Simultaneously the coupling of new system outputs on existing signalisation is solved. (author)

  12. From links calibration toward hydraulic network tuning applied to RCW System (BSI - 71340) of the Cernavoda U1 Full - Scope Simulator

    International Nuclear Information System (INIS)

    A new algorithm to compute the characteristic parameters of the hydraulic network in order to increase the simulation fidelity versus real plant response is presented. The new solution is compared with the classic method of the links calibration and applied to the Recirculated Cooling Water system, which is a representing system from the hydraulic network point of view. This new method was developed by the Cernavoda U1 Simulator team and is proposed to be used for upgrading and tuning the models. (authors)

  13. Achievements and challenges of Paks NPP

    International Nuclear Information System (INIS)

    As the six year long safety upgrading program at Paks NPP is approaching its final stage this year, it is a good opportunity to draw the conclusion: what have been done and how have measures influenced the safety of the plant. In its first part the paper gives an overview of the program's main issues, assesses the results from the point of view of safety, reliability and cost effectiveness as well. In the second part a survey of future tasks follows: (1) Hungary is joining to the EU. The accession process so far has not revealed any major problems concerning nuclear safety which could be seen as obstacles toward the membership. However the plant should be ready to meet the increasing level of safety regulations. Further safety upgrading measures are planned, mostly in the field of severe accident management. (2) The electricity market liberalisation in Hungary will start in 2003 and being a EU member state, the full market opening will happen within a few years. The plant has to take into account the specificity of market functioning. The most important thing is to preserve the present cost advantage of nuclear electricity generation within the market conditions. The paper presents measures performed and planned to keep the unit generation cost competitive. (3) The first unit at Paks will mark its 20't'h anniversary this year. Lifetime management issues are at the centre of the engineering activities. The work already started to prepare the lifetime extension for 20 years. The program for the license renewal, which was elaborated jointly with the nuclear regulatory body will be described.(author)

  14. Operational experience of fuel assembly TVS-2 at Balakovo NPP

    International Nuclear Information System (INIS)

    TVS-2 operational history, main goals of TVS-2 development like: creation of fuel assembly (FA) with hard casing, able to resist bending and rotating loads at loose interaction of fuel elements with spacer grids (SG) cells during operation and creation of FA, able to work under prolonged fuel cycles, i.e., permitting to achieve more depth of burn up and also main solutions, accepted for TVS-2 construction like: 1) Hard armed casing, created by direct welding of spacer grids (SG) to control rod guides (CRG); 2) Hard to bending SG increased up to 30 mm high (instead of 20 mm for UTVS); 3) Special construction of SG cells to reduce forces on fuel elements sliding; 4) For CRG was used alloy E635 to improve casing stability; 5) Enforced end parts to improve FAs stability are presented in this paper. Types of TVS-2, used at Balakovo NPP, RPS CR drop time at imitation of EP actuation after reactor shutdown for reloading (Unit 1), RPS CR withdrawal forces before reactor startup after reloading (Unit 1), FAs bents after reactor shutdown for reloading (Unit 1) and FA clad condition of reactors at Units 2, 3, 4 as well as at Unit 1 are shown. At the end the following further activities at Balakovo NPP are listed: 1) Continue industrial operation of TVS-2; 2) Shift units to fuel cycle 3 * 16-18 months on basis months on basis of TVS of TVS-2 -2 with the purpose improve capacity factor; 3) Enhance units capacity up to 104 % Nnom; 4) Increase vertical speed of FAs, movement in reactor, SFP, FAC up to 1 and and 2 m/min. accordingly; 5) Implement TVS-2M, having big mass of fuel due to increase of the fuel pillar (on 150 mm) and decrease of pellet hole (up to 1,2 mm)

  15. Study on issues of CPR1000 NPP emergency diesel generator test

    International Nuclear Information System (INIS)

    During the design of CPR1000 NPP, there is no special loads for emergency diesel generator tests, and there is no enough loads in emergency cabinets for the tests. In order to perform the test while do not occupy the outage critical time, a Mobile Test Load solution is provided in this paper. According to the existing CPR1000 design, dry mobile loads, breaker for interface with emergency diesel generator, and 2 junction boxes for interface with additional diesel generator are proposed. It is suggested that the interface and test loads for multi-units and multi-plants usage to be considered in NPP design phase. (authors)

  16. MAFES, HUMOS and LEMOP diagnostic systems - applications in NPP Temelin

    International Nuclear Information System (INIS)

    Material Fatigue Monitoring System (MAFES), Humidity Monitoring System (HUMOS) and Leak Monitoring Program (LEMOP) have been developed for application in VVER 440 and VVER 1000 nuclear power plants. Plant instrumentation and control system data and supplementary instrumentation data are used as inputs into MAFES on-line systems. A specific software has been developed and implemented for Temelin application to: a) measure and record data of interest; b) calculate stress components and principle stresses in structural material; c) calculate usage factor; and d) generate rain flow counting matrices especially for in metal temperature transients in selected sensitive locations of NPP safety related components. Algorithms used in the Temelin software applications are based on ASME Boiler and Pressure Vessel Codes. Experience gained from the operation of MAFES systems at Temelin Unit 1 and Unit 2, as well as selected temperature transients and benefits of MAFES systems are discussed in the paper. HUMOS and LEMOP on-line systems have been developed and designed to detect the presence of leaks in selected primary circuit high energy pipelines and components and evaluate the leaks from the point of view of Leak Before Break (LBB) requirements. HUMOS does not rely on the release of radioactivity to detect leaks, rather is based on detection of moisture changes in the air resulting from primary circuit boundary leaks. Because HUMOS relies on moisture detection, leaks can be detected without requiring the reactor to be critical. Therefore leaks can be detected during integrity pressure tests and any other mode of NPP operation where the standard reactor ventilation system is operating and primary circuit and components are pressurized by water. LEMOP is an acoustic system with sensors on waveguides coupled to outer walls of the primary circuit at selected positions. Selected results from HUMOS and LEMOP systems testing and operation at NPP Temelin are documented and discussed

  17. Nuclear disasters at Chornobyl NPP, Fukushima NPP and nuclear power engineering in the 21- century

    International Nuclear Information System (INIS)

    The article presents a brief analysis of nuclear accidents at the Chornobyl NPP 91986) and Fukushima NPP (2011), discusses causes and scenarios of the accidents. The radioactive contamination of the environment resulting from the disasters is characterized, and top-priority actions for mitigation of the consequences and protection of public are discussed

  18. Selection of compositions for the cementation of liquid radioactive waste of Kudankulam NPP and Volgodonskaya NPP

    International Nuclear Information System (INIS)

    The purpose of this work is the selection of formulations for the cementation of liquid radioactive waste of Kudankulam NPP and Volgodonskaya NPP. The simulators of the following radioactive waste have been used for the works: concentrated still bottoms (CSB) with saline content 600-800 g/l, sludge, pulps of ion-exchange resins (IER), activated carbon, titanium and ion-exchange sorbents of Kudankulam NPP and concentrated still bottoms with saline content 900 g/l, pulps of ion-exchange resins, sludge of Volgodonskaya NPP. For Kudankulam NPP there was made a separate research of the cementation of each type of waste and also joint cementation of concentrated still bottoms and ion-exchange resin. For Volgodonskaya NPP - joint cementation of CSB and IER or sludge. The properties of the compounds were determined, which are regulated by GOST R 51883-2002, spread ability and setting time of the cement grouts. The study has shown that as a main component of the combined binding material for the cementation of low level radioactive waste (LRW) of Kudankulam NPP and Volgodonskaya NPP, the usage of Portland cement is preferable. As additives for the binding materials it is better to use lime and bentonite clay powder. Maximal inclusion of LRW into the compound when using these materials will be (% of the compound weight): CSB: 30%, sludge - 14%, IER - 14%, activated carbon - 18%, titanium sorbent - 20%, ion-selective sorbent - 14%

  19. Conceptual design of covering method for the proposed LILW near-surface repository at Cernavoda

    International Nuclear Information System (INIS)

    The disposal concept of the low and intermediate level (LIL) wastes resulting during NPP operation combines both the natural and engineered barriers in order to ensure the safety of the environment and population. Saligny site has been proposed for LIL waste disposal. Preliminary performance assessments indicate that the loess and clay layers are efficient natural barriers against water flow and radionuclide migration through the vadose zone to the local aquifers. At present, the studies on site characterization are concentrated on investigation of the potential factors affecting the long-term integrity of the disposal facility. This analysis showed that surface erosion by wind and water and bio-intrusion by plant roots and burrowing animals could affect the long-term disposal safety. Based on the preliminary erosion results, as well as on the high probability of bio-intrusion by the plant roots and burrowing animals (i.e. moles, mice), different covering systems able to ensure the long-term safety of the repository has been proposed and analyzed. FEHM and HYDRUS 2D water flow simulations have been performed in order to compare their efficiency in the diminution of the infiltration rate in the repository. From this point of view, the covering system combining the capillary barrier and the resistive layer proved to have the best behavior

  20. Management of the fuel cycles and fuel performance analyses in the Kozloduy NPP WWER-440 reactors

    International Nuclear Information System (INIS)

    The basic characteristics of the previous fuel cycles carried out on Units at the Kozloduy NPP are described in this report. Design optimization methods and safety assessments of specific fuel reloads are presented. The tasks related to the fuel performance efficiency enhancement are reviewed. Advanced fuel implementation possibilities and achieved results in the Kozloduy NPP WWER reactors are discussed. Some basic results obtained by fuel behavior analyses are presented and discussed as well. Computational and experimental investigations of the WWER -440 fuel rod limiting maximal linear power are presented and compared with operational data. On the basis of the present operational experience and the analyses performed, conclusions and proposals for better and more efficient fuel and fuel cycle utilization are made. Up to now the Kozloduy NPP WWER-440 reactors produced totally about 70 fuel cycles. (author)