Document status for 1 and 2 Kozloduy NPP decommissioning activities -Phase 'Final Shutdown'

International Nuclear Information System (INIS)

Vangev, A.; Boyadjiev, Z.

1997-01-01

Decommissioning process (D and D) is the final phase of each nuclear reactor life cycle. The first nuclear reactor generation has reached his expiration life date. Decommissioning working documentation had not been taken into account at the project and construction stage. The decommissioning activities, planning and legislation has to develop along their operation. Most of developed nuclear energetic countries have gathered good experience and have create their own decommissioning strategy. This report represents in brief an overview of different country's approaches and the Kozloduy NPP decommissioning activity intention in near future and reviews the D and D working document status for 1 and 2 Kozloduy NPP Units decommissioning. Kozloduy NPP D and D task to the moment is to plan the first stage of the decommissioning process - 'The Final Shutdown' and to prepare the working documents for the phase execution. The Final Shutdown of Kozloduy NPP - 1 is the termination of operation of the Units 1 and 2 and the electricity production cessation after their useful life exhaust. In accordance with the legal legislation in Bulgaria only the normal planned termination of operation on units 1 and 2 should be prescribed. The project results concern the initial condition of the equipment and systems, their preparation and sequence for defueling, decontamination and dismantling. A plan for activities' organization for D and D and Complex Characterization of the Site under consideration will contain the following documents: 1. Time-schedule for the sequence of activities during the stages of the Final Shutdown and Safe Enclosure preparation. Technical project for organization of work related to Final Shutdown; 2. Complex Characterization Programme for a condition investigation of the Units 1 and 2 equipment and systems. 3. Technical project for design modifications and dismantling of equipment and systems which violate the radiation and nuclear safety during the Final Shutdown

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

International Nuclear Information System (INIS)

Antonov, D.

2000-01-01

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)

Radioactive waste problems in the Kozloduy NPP

Energy Technology Data Exchange (ETDEWEB)

Videnov, N; Stanchev, V [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1996-12-31

An average volume of 1400 m{sup 3} a year of solid radioactive waste (RAW) is generated in the Kozloduy NPP. The adopted waste processing sequence is collection, sorting and compaction with a 1000 tons force providing decrease in volume by factor of 15. A temporary storage facility at the Kozloduy NPP is licensed by ISUAE and CPPUAE. The treatment of liquid wastes is performed by Westinghouse formula and a technology using an automated solidification system. Contaminated oils are burned using an oil incinerator. A special 2-year programme for RAW management is being developed.

Radioactive waste problems in the Kozloduy NPP

International Nuclear Information System (INIS)

Videnov, N.; Stanchev, V.

1995-01-01

An average volume of 1400 m 3 a year of solid radioactive waste (RAW) is generated in the Kozloduy NPP. The adopted waste processing sequence is collection, sorting and compaction with a 1000 tons force providing decrease in volume by factor of 15. A temporary storage facility at the Kozloduy NPP is licensed by ISUAE and CPPUAE. The treatment of liquid wastes is performed by Westinghouse formula and a technology using an automated solidification system. Contaminated oils are burned using an oil incinerator. A special 2-year programme for RAW management is being developed

Response and capacity evaluation of unit 1-2, Kozloduy NPP

International Nuclear Information System (INIS)

Kostov, M.; Stefanov, D.; Boncheva, H.

1993-01-01

Investigation described in this presentation was performed within the WANO Program for seismic safety assessment of Kozloduy NPP. The investigation is imposed by the necessity of seismic upgrading of the structures and equipment of the plant for the new design basic earthquake. Term of reference for this study was elaborated by experts of IAEA

The main conditions ensured problemless implementation of 235U high enriched fuel in Kozloduy NPP (Bulgaria) - WWER-1000 Units

International Nuclear Information System (INIS)

Dobrevski, I.; Zaharieva, N.; Minkova, K.; Michaylov, G.; Penev, P.; Gerchev, N.

2009-01-01

The collected water chemistry and radiochemistry data during the operation of the Kozloduy NPP Unit 5 for the period 2006-2009 (12-th, 13-th 14-th and 15-th fuel cycles) undoubtedly indicate for WWER-1000 Units (whose specific features are: Steam generators with austenitic stainless steel 08Cr18N10T tubing; Steam generators are with horizontal straight tubing and Fuel elements cladding material is Zr-1%Nb (Zr1Nb) alloy), that one realistic way for problemless implementation of 235 U high enriched fuel have been found. The main feature characteristics of this way are: Implementation of solid neutron burnable absorbers together with the dissolved in coolant neutron absorber - natural boric acid; Application of fuel cladding materials with enough corrosion resistance by the specific fuel cladding environment created by presence of SNB; Keeping of suitable coolant water chemistry which ensures low corrosion rates of core- and out-of-core- materials and limits in core (cladding) depositions and restricts out-of-core radioactivity buildup. The realization of this way in WWER-1000 Units in Kozloduy NPP was practically carried out through: 1) Implementation of Russian fuel assemblies TVSA which have as fuel cladding material E-110 alloy (Zr1Nb) with enough high corrosion resistance by presence of sub-cooled nucleate boiling (SNB) and use burnable absorber (Gd) integrated in the uranium-gadolinium (U-Gd 2 O 3 ) fuel (fuel rod with 5.0% Gd 2 O 3 ); 2) Development and implementation of water chemistry primary circuit guidelines, which require the relation between boric acid concentration and total alkalising agent concentrations to ensure coolant pH 300 = 7.0 - 7.2 values during the whole operation period. The above mentioned conditions by the passing of WWER-1000 Units in NPP Kozloduy to uranium fuel with 4.4% 235 U (TVSA fuel assemblies) practically ensured avoidance of the creation of the necessary conditions for AOA onset. The operational experience (2006-2009) of the

Seismic safety of building structures of NPP Kozloduy III

International Nuclear Information System (INIS)

Varbanov, G.I.; Kostov, M.K.; Stefanov, D.D.; Kaneva, A.D.

2005-01-01

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)

Positive and negative aspects of the Kozloduy NPP; AEhS Kozloduy - plyusy i minusy

Energy Technology Data Exchange (ETDEWEB)

Kouzmanov, K [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1996-12-31

This opening address delivered by the Kozloduy NPP General Director summarizes the benefits and drawbacks of the Kozloduy NPP. It is emphasized that the plant supplies 40% of the national electricity demand and has been running without any accidents or environmental contamination. The production cost of the electricity produced is between two and three times less than the one from thermal stations. Among the disadvantages are: great initial investments; the need to handle and store properly the radioactive waste; the need for modernization and reconstruction in order to improve safety.

Response of the main building, unit 5, Kozloduy NPP (Bulgaria) to an explosion input motion

International Nuclear Information System (INIS)

Kostov, M.; Boncheva, H.; Varbanov, G.; Kaneva, A.; Stefanov, D.; Koleva, N.

1999-01-01

The main building of Unit 5, NPP Kozloduy is one of the two selected prototypes of WWER-type plants included in the project 'Benchmark study for seismic analysis and testing of WWER-type nuclear power plants', co-ordinated by IAEA. The dynamic in-situ testing of the structure of Unit 5 WWER-1000 MW reactor containment building and the adjacent auxiliary structures is performed by specialists of ISMES (Italy), assisted by Hungarian consultants (GEOPARD) and Bulgarian specialist of NPP Kozloduy. The aim of the experiment is to assess the dynamic characteristics and behaviour of the structures, the soil-structure interaction effects, the equipment-structure interaction, etc. The dynamic excitation is a low level ground motion induced by underground explosions. The measuring of the response is done at different pre-selected structure points. Two experiments are performed. The registrations during the second experiment of 01.07.1996 are used in the present report. One set of free field records are given up to the participant institutions for the benchmarking. The purpose is to perform a dynamic analysis of the main building of Unit 5, to assess the response to the explosion ground motion and to compare the analytical results with the recorded motion. In this report are discussed soil and structure modelling and computation results consisting in acceleration response spectra obtained at foundation level and at different points of the structure

Low level radioactive waste disposal in Kozloduy NPP in Bulgaria

International Nuclear Information System (INIS)

Stanchev, V.

2001-01-01

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)

Operational benchmark for VVER-1000, unit 6, Kozloduy NPP

International Nuclear Information System (INIS)

Apostolov, T.; Petrov, B.

1999-01-01

Benchmark calculations have been carried out using the 3D nodal code TRAPEZ. Global 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 components descriptions as well as material compositions are given. The results presented include the critical boric acid concentration, the radial power distribution, the axial power distribution for the maximum overload 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. The information presented could serve as a test case for validation of code packages designed for analyzing the steady-state operation of VVERs. (author)

Kozloduy NPP - its 20 years operational experience; AEhS `Kozloduy`: 20-letni opyt ehksploatatsii

Energy Technology Data Exchange (ETDEWEB)

Yankov, M; Grizanov, I; Sabinov, S [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1996-12-31

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.

New excitation equipment for 220 MW generators in Kozloduy NPP

International Nuclear Information System (INIS)

Tomerlin, D.

2001-01-01

Rehabilitation on the excitation equipment for Generator 5, Reactor Unit 3, in Kozloduy NPP was completed in November 2000. ABB's Static Excitation System based on UNITROL 5000 technology has been chosen by the Bulgarian National Utility and Kozloduy NPP to substitute the original Russian excitation system equipment with electro-magnetic voltage regulators. The substitution is in a rehabilitation package of four excitation system equipment for Generator 5 and 6 of Reactor Unit 3 and Generator 7 and 8 of Reactor Unit 4 after a short overview of the original excitation system this paper describes the new Static Excitation System UNITROL 5000 including configuration with block diagram, its main features and merits such as modes of operation, limiter, special control functions and diagnostic facilities. Furthermore, new facilities, which are implemented in UNITROL 5000, such as dynamic current distribution among the thyristors working in parallel as well as the start-up from the residual magnetism are mentioned. Special functions including a so-called free-running mode of operation and automatic change over sequence from new excitation system to the stand-by excitation system, which is DC exciter machine, are described. Some records of the transient responses performed during the commissioning and a photograph of a manufactured system are provided. (author)

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

Energy Technology Data Exchange (ETDEWEB)

Minkova, K. [Kozloduy NPP (Bulgaria)

2002-07-01

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)

Project realization of jet vortex condenser at units 3 and 3 of the Kozloduy NPP

International Nuclear Information System (INIS)

Genovski, I.; Grigorov, A; Bonev, B; Sabinov, S.; Petkov, M.

2003-01-01

In the implementation of the contract between the Kozloduy NPP and Department 'Thermal and Nuclear Energy' at the Technical University, Sofia a project has been realized for the demonstration of the modernization of the system for accident localization in the units 3 and 4, based on the jet-vortex condenser (JVC). The final result is multimedia presentation in English and Bulgarian languages. In this paper the last part of the project is presented, including: installing of the JVC, auxiliary systems, executors of the project and expert opinions on the projects

Assessment of the state of modernization of NPP Kozloduy units 3 and 4

International Nuclear Information System (INIS)

Horstmann, R.

2002-01-01

The status of the implemented modernization programmes for the Kozloduy NPP is presented. The Three Stage Term Modernization Program for units 1-4 has been implemented between 1991 and 1997 and includes the installation of new safety systems and components such as pressurized safety valves, main steam safety valves, complementary emergency feedwater system, second fire fighting system etc. The total investment od the Program amounted to 129.1 mill. ECU. The Complex Modernization Program for units 1-4 has been developed 1996 -1997 and further updated in 2000. The total investment necessary for the implementation are assessed at about 66 mill. USD. The safety assessment shows that due to the modernization programs the units have been upgraded to additional accident management capabilities. The reactor confinement has been fundamentally improved by the Jet Vortex Condenser System. PSA has been also conducted for the units 3 and 4

Testing of components on the shaking table facilities of AEP and contribution to full scale dynamic testing of Kozloduy NPP. Final report

International Nuclear Information System (INIS)

Ambriashvili, Y.

1999-01-01

Units 5 and 6 of the Kozloduy NPP were designed as a standardized WWER-1000 on the basis standardized scheme designs, including building structures and reactor building. The accelerograms and response spectrum were adopted based on seismological, geological, geophysical and other conditions of the region where the NPP is expected to be located. This paper presents the results design floor response spectra analysis as well as method and some results of the tests of electrical equipment as identified by the Kozloduy NPP staff

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

International Nuclear Information System (INIS)

Velev, V.; Mancheva, K.

2006-01-01

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

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)

1999-01-01

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

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

International Nuclear Information System (INIS)

Erve, M.; Heck, R.; Schmidt, J.; Daum, G.; Bataklieva, L.; Stoev, M.

1999-01-01

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)

Morbidity with temporary disability in Kozloduy NPP workers

International Nuclear Information System (INIS)

Dobreva, B.; Novkirishki, V.

1993-01-01

Changes with time in indicators of disease incidence with temporary disability in Kozloduy NPP personnel have been studied for the period 1974-1991. The data were compared with those for 'Sofia-Iztok' TPP. The causes contributing to formation of the indicators of frequency, severity, and average duration were examined. No temporary disability because of radiation exposure has been recorded. As a whole, less temporary disability has been found at NPP than at TPP. (author)

Four years Re-Use of low burned fuel assemblies from units 1 and 2 in core loadings of units 3 and 4 WWER-440 at Kozloduy NPP

International Nuclear Information System (INIS)

Stoyanova, I.; Antov, A.; Spasova, V.

2006-01-01

At the end of 2002 units 1 and 2 of Kozloduy NPP were shutdown before their design life time which left a large number of assemblies yet with a significant energy resources. A decision to load these assemblies into the cores of Units 3 and 4 during the next 4 cycles has been taken. In 2003, 43 assemblies from Unit 1 cycle 23 rd and 55 assemblies from Unit 2 cycle 24 th are loaded in the cores of units 3 and 4 respectively. In 2004, new 49 assemblies from Unit 1 cycle 23rd and new 55 assemblies from Unit 2 cycle 24th are loaded in the cores of units 3 and 4 respectively. In 2005, the next new 25 assemblies from Unit 1 cycle 23 rd and 66 assemblies from Unit 2 cycle 24th are loaded in the cores of units 3 and 4 respectively. In 2006, the next new 54 assemblies from Unit 1 cycle 23 rd and 52 assemblies from Unit 2 cycle 24 th + 2 assemblies from Unit 3 cycle 19th are loaded in the cores of Units 3 and 4 respectively. The SPPSHB computer code system is used for development and safety assessment of the fuel loading patterns of Units 3 and 4 at Kozloduy NPP with low burned assemblies from units 1 and 2 (Authors)

Floor response spectra for seismic qualification of Kozloduy VVER 440-230 NPP

International Nuclear Information System (INIS)

Kostov, M.K.; Prato, C.A.; Stevenson, J.D.

1993-01-01

In this paper the floor response spectra generation methodology for Kozloduy NPP, Unit 1-2 of VVER 440-230 is presented. The 2D coupled soil-structure interaction models are used combined with a simplified correction of the final results for accounting of torsional effects. Both time history and direct approach for in-structure spectra generation are used and discussion of results is made

Floor response spectra for seismic qualification of Kozloduy VVER 440-230 NPP

Energy Technology Data Exchange (ETDEWEB)

Kostov, M.K. [Bulgarian Academy of Sciences, Sofia (BG). Central Lab. for Seismic Mechanics and Earthquake Engineering; Ma, D.C. [Argonne National Lab., IL (United States); Prato, C.A. [Univ. of Cordoba (AR); Stevenson, J.D. [Stevenson and Associates, Cleveland, OH (US)

1993-08-01

In this paper the floor response spectra generation methodology for Kozloduy NPP, Unit 1-2 of VVER 440-230 is presented. The 2D coupled soil-structure interaction models are used combined with a simplified correction of the final results for accounting of torsional effects. Both time history and direct approach for in-structure spectra generation are used and discussion of results is made.

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

International Nuclear Information System (INIS)

Jordanov, M.; Marinov, M.; Krutzik, N.

2001-01-01

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)

Modernization program of NPP Kozloduy, units 5 and 6

International Nuclear Information System (INIS)

Protze, M.

2000-01-01

A rather brief overview is given of the programme for upgrading units 5 and 6 of the Bulgarian Kozloduy plant, as it was established in 1994/95. A brief characterization is given of individual steps, either already taken or being planned. (A.K.)

Development of the NPP Kozloduy informational system

Energy Technology Data Exchange (ETDEWEB)

Katsarov, Y; Manchev, B [Risk Engineering Ltd., Sofia (Bulgaria)

1996-12-31

A unified computer system to be implemented in the Kozloduy NPP is described. It allows to generate all general indicators and documents for plant operation needed according to the national regulation and WANO Performance Indicators. The system combines multi-purpose data collection with probabilistic analysis, evaluation of the human factor and optimization of the regulated verification of the equipment. 3 refs.

Experience with Periodic Safety Review (PSR) at Kozloduy NPP after 20 years of operation

International Nuclear Information System (INIS)

Popov, V.

2011-01-01

Conclusion: Measures in the long-term Programs for improving safety and radiation protection of unit 5&6, based on PSR outcome and addressed on the units’ operation licence renewal are under way. • NPP Kozloduy intends to fulfils requirements on modern nuclear power plants which occasionally exceeds limits of the effective national nuclear legislation

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)

1996-01-01

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

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)

1999-01-01

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

Seismic hazard analysis of the NPP Kozloduy site

International Nuclear Information System (INIS)

Petrovski, D.; Stamatovska, S.; Arsovski, M.; Hadzievski, D.; Sokerova, D.; Solakov, D.; Vaptzarov, I.; Satchanski, S.

1993-01-01

The principal objective of this study is to define the seismic hazard for the NPP Kozloduy site. Seismic hazard is by rule defined by the probability distribution function of the peak value of the chosen ground motion parameter in a defined time interval. The overall study methodology consists of reviewing the existing geological, seismological and tectonic information to formulate this information into a mathematical model of seismic activity of the region and using this assess earthquake ground motion in terms of probability. Detailed regional and local seismological investigations have been performed. Regional investigations encompass the area within a radius of 320 km from the NPP Kozloduy site. The results of these investigations include all seismological parameters that are necessary for determination of the mathematical model of the seismicity of the region needed for the seismic hazard analysis. Regional geological and neotectonic investigations were also performed for the wider area including almost the whole territory of Bulgaria, a large part of Serbia, part of Macedonia and almost the whole south part of Romania

Trends and results in In-Core management for the Kozloduy NPP WWER-440 reactors

International Nuclear Information System (INIS)

Haralampieva, Tz.; Antov, A.; Georgieva, N.; Spasova, V.

2001-01-01

The paper presents the experience gained during the design and operation of the last fuel cycles of the four WWER-440/V-230 units at Kozloduy NPP. High efficiency and economy of the fuel utilization requires very precise procedures for fuel in-core management, including calculations and analyses for reloading scheme design, compared with results from operational measurements and fuel cycle efficiency. The paper describes the main stages of implementation of advanced fuel assemblies in the Kozloduy NPP WWER-440 reactors. New advanced fuel has been implemented after the completion of comprehensive neutron-physical, thermal-hydraulic and thermal-mechanical analyses by using advanced computer codes. As a general task of the fuel cycle improvements it is pointed the increasing of the final fuel burnup and decreasing of the number of spent fuel assemblies. Series of calculations and analyses, related to the introducing of the advanced fuel assemblies and improvement of the fuel cycle characteristics have been carried out to guarantee the safe operation and fuel reliability

Start up physics tests of units 5 and 6 (WWER 1000) at Kozloduy NPP by comparison with the calculated neutron physics characteristics

International Nuclear Information System (INIS)

Antov, A.; Stoyanova, I.

2008-01-01

In conjunction with each refuelling shutdown of the reactor core, nuclear design calculations are performed to ensure that the reactor physics characteristics of the new core will be consistent with the safety limits. Prior to return to normal operation, a physics test program is required to determine if the operating characteristics of the core are consistent with the design predictions and to ensure that the core can be operated as designed. Successful completion of the physics test program is demonstrated when the test results agree with the predicted results within predetermined test criteria. Successful completion of the physics test program and successful completion of other tests, which are performed after each refuelling provides assurance that the plant can be operated as designed. The calculated neutron-physics characteristics values of Kozloduy NPP Unit 5 and Unit 6 (WWER 1000) obtained by the computer code package KASKAD are compared with the obtained results during the start up physics tests. The core fuel loading consists of 163 fuel assemblies (FAs). The calculated values are given according to actual experimental conditions of the reactor core during start up physics tests. The report includes comparisons between calculation results by code package KASKAD (BIPR7A) and experimental data values of main neutron-physics characteristics during start up physics tests in selected recent cycles of Kozloduy NPP Unit 5 and Unit 6. (authors)

Start up physics tests of Units 5 and 6 (WWER-1000) at Kozloduy NPP by comparison with the calculated neutron physics characteristics

International Nuclear Information System (INIS)

Stoyanova, I.; Antov, A.

2007-01-01

In conjunction with each refuelling shutdown of the reactor core, nuclear design calculations are performed to ensure that the reactor physics characteristics of the new core will be consistent with the safety limits. Prior to return to normal operation, a physics test program is required to determine if the operating characteristics of the core are consistent with the design predictions and to ensure that the core can be operated as designed. Successful completion of the physics test program is demonstrated when the test results agree with the predicted results within predetermined test criteria. Successful completion of the physics test program and successful completion of other tests which are performed after each refuelling provides assurance that the plant can be operated as designed. The calculated neutron-physics characteristics values of Kozloduy NPP Unit 5 and Unit 6 (WWER 1000) obtained by the computer code package KASKAD are compared with the obtained results during the start up physics tests. The core fuel loading consists of 163 fuel assemblies. The calculated values are given according to actual experimental conditions of the reactor core during start up physics tests. The report includes comparisons between calculation results by code package KASKAD (BIPR7A) and experimental data values of main neutron-physics characteristics during start up physics tests in selected recent cycles of Kozloduy NPP Unit 5 and Unit 6 (Authors)

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

Energy Technology Data Exchange (ETDEWEB)

Khristova, R; Kaltchev, B; Dimitrov, B [Energoproekt, Sofia (Bulgaria); Nedyalkova, D; Sonev, A [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1996-12-31

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.

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

International Nuclear Information System (INIS)

Khristova, R.; Kaltchev, B.; Dimitrov, B.; Nedyalkova, D.; Sonev, A.

1995-01-01

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

A comparison of the Kozloduy NPP and Temelin NPP I and C projects

International Nuclear Information System (INIS)

Cook, B.M.

2004-01-01

Because Kozloduy NPP and Temelin NPP are both VVER 1000 plants of roughly the same vintage, they are very similar in design. However, from the viewpoint of their I and C modernization projects, there are significant differences between these plants. Some of these differences stem from the evolution of I and C technology over the relatively short period between the two projects. Other differences arise from the fact that the Kozloduy project is a phased upgrade of the I and C systems in an operating plant while the Temelin project was a 'one time' installation of the entire plant I and C system. This paper discusses these differences as well as trends in the nuclear I and C field that will shape the industry in the future. In addition to technology evolution, the comparative advantages or problems in phased upgrade versus 'one time' installations are discussed. Conclusions drawn provide insight for the planning of future I and C upgrades in VVERs and other types of nuclear power plants. (author)

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)

1999-01-01

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

Nuclear fuel utilization in Kozloduy NPP

Energy Technology Data Exchange (ETDEWEB)

Boyadzhiev, Z; Kharalampieva, Ts; Pejchinov, Ts [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1994-12-31

An assessment of fuel utilization in Kozloduy NPP units 1-6 is made on the basis of operational data obtained for a total of 62 fuel cycles. Basic characteristics of core loading and operation conditions are given. SPPS-1 and BIPR-7 codes are used to calculate assembly-wise power distributions for different full power days of a given cycle and unit. The data are compared with the measured values of these quantities. The analysis performed shows that the core loading option chosen has led to efficient fuel utilization without violation of the nuclear safety criteria. For WWER-440 (Units 1 - 4) this is expressed in effective reduction of the reactor vessel irradiation, maintaining the design duration of the fuel cycles at a reduced number of assemblies by a factor 5 - 5-10%, utilizing fuel with higher enrichment and implementing the 4-year fuel cycle. For WWER-1000 the improvements lead to: adoption of the 3-year fuel cycle utilizing fuel with 4.4% initial enrichment, implementation of improved fuel with a new type of absorbers and more effective low-leakage core loading patterns. 10 tabs., 6 figs., 7 refs.

Neutron embrittlement of the Kozloduy NPP unit 1 reactor

International Nuclear Information System (INIS)

Vodenicharov, S.; Kamenova, Tz.

1996-01-01

Activities made in the period 1989-1996 according to the Program for metal state monitoring of the Kozloduy NPP Unit 1 are described. Data on P and Cu content in the welded joint 4 are reported. Determination is made by wet chemical analysis of shavings taken out from the inner side of the wall, direct spectral analysis of the vessel itself and spectroscopy of the inner and outer side of 6 templates. The results obtained from 4 different study teams showed a good agreement. The real average P content is 0.046% and tends to diminish in depth. Microstructural investigation does not show any expressed inter-crystalline mechanism of brittle failure at low temperatures. The data on real P and Cu content, as well as the experimental values of the initial critical temperature of embrittlement (Tk o ), the residual part of temperature shift (Tk r ) and the re-embrittlement temperature after annealing at 475 o (Tk) allow to predict the change in Tk o of the joint 4 during the next refueling cycles. The measured low value of Tk after 18-th refueling cycle is considerably lower than that forecasted by lateral re-embrittlement law. This means that the forecasting of Tk for the next cycles is made with big enough conservatisms, and that a second annealing of the vessel until 26-th cycle is not necessary. So according to the most conservative estimate, the Unit 1 can operate safely until the end of the 26-th refueling cycle. It is also concluded, that in terms of radiation degradation of the vessel metal the operation life time of the Unit 1 can reach and exceed the designed one. 2 tab., 7 ref

Nuclear fuel utilization at the Kozloduy NPP

Energy Technology Data Exchange (ETDEWEB)

Boyadzhiev, Z [Kombinat Atomna Energetika, Kozloduj (Bulgaria); Kharalampieva, Ts; Pejchinov, Ts

1996-12-31

Data on core loading and operation conditions during past fuel cycles of the Units 1 to 6 at the Kozloduy NPP are presented. The Units 1 and 2 have reached average discharge fuel burn-up of 31 MW d/kg U, the Unit 3 - 34 MW d/kg U and the Unit 4 - 36.5 MW d/kg U. By use of dummies and low-leakage core loading patterns for WWER-440 cores an effective reduction in reactor pressure vessel irradiation is obtained. By increasing the enrichment level and improving the characteristics of the Units 3 and 4, a design fuel cycles duration has been reduced by 5-10% in number of assemblies. Core loading design has been modelled using computer codes SPPS-1, BIPR-7, ALBOM, PROROC. A 3-year fuel cycle utilizing 4.4% enriched fuel proved to be more efficient for WWER-1000 by 15% reduction in fuel cost compared to the 2-year cycle. Future developments include improvements of the in-core monitoring system and process on-line simulation based on more accurate computer codes. 7 refs., 6 figs., 10 tabs.

Determining the Residual Lifetime of Qualified Electrical and I and C Equipment in Units 5 and 6 of Kozloduy NPP

International Nuclear Information System (INIS)

Radoslavov, Biser

2012-01-01

The proposed paper clarifies the environmental qualification and residual lifetime of installed equipment and electrical cables in operating WWER 1000 type units 5 and 6 of Kozloduy NPP. The qualification approach is a combination of analyses and tests in consideration of some specific features of WWER equipment. As a result of the study, selected equipment is divided in 26 groups. Qualification groups include similar types of equipment with equal resistance to foreign impacts, analogous critical parts, and same methods of control and estimation of residual lifetime. Qualification protocols were made for each group. (author)

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)

1999-01-01

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

Preparation for decommissioning of the Kozloduy Nuclear Power Plant units 1 and 2

International Nuclear Information System (INIS)

Delcheva, T.; Ribarski, V.; Demireva, E.

2006-01-01

The first decommissioning strategy of units 1 and 2 of Kozloduy NPP (KNPP) stipulated 3 phases: a 5 year phase including the post operation activities and preparation of the safe enclosure (SE); a 35 years SE period, followed by deferred dismantling. 'Updated Decommissioning Strategy for Units 1-4 of Kozloduy NPP' was issued in June 2006. The Updated Strategy is based on the so called 'Continuous Dismantling' Concept. The updated Strategy starts preparatory work earlier and then moves into dismantling work without a significant gap. The aim is to achieve a more optimal distribution of the dismantling activities along the time, saving jobs and the existing knowledge of the plant personnel during the decommissioning, and ensuring smooth and more effective use of financial and human resources and of the available infrastructure for waste treatment. This paper gives general information about the updated strategy and activities required for its implementation. (author)

Methods, means and results from containment leakage decrease in unit 2 at Kozloduy NPP with international participation

Energy Technology Data Exchange (ETDEWEB)

Demireva, E; Grigorov, D; Balabanov, E [Energoproekt, Sofia (Bulgaria)

1996-12-31

A study of the Kozloduy NPP Unit 2 containment improvement has been carried out. The following objectives are identified: to assess confinement tightness (local tests); to improve tightness; to perform the most urgent repair works; to develop global test procedures including leak tightness at nominal and reduced pressure, structural integrity test and venting flaps reliability test. Nine groups of potential leakage paths have been determined. The ventilation system has been found as the major source of expected leakage having 60 penetrations with size above 250 mm. Proposed modifications of the ventilation system include reduction of the number of inflow and suction valves, replacement of some valves with a better quality ones and installation of isolating valves. It is planned to transfer the experience and results of this study to the other WWER-440 units. 1 ref.

Methods, means and results from containment leakage decrease in unit 2 at Kozloduy NPP with international participation

International Nuclear Information System (INIS)

Demireva, E.; Grigorov, D.; Balabanov, E.

1995-01-01

A study of the Kozloduy NPP Unit 2 containment improvement has been carried out. The following objectives are identified: to assess confinement tightness (local tests); to improve tightness; to perform the most urgent repair works; to develop global test procedures including leak tightness at nominal and reduced pressure, structural integrity test and venting flaps reliability test. Nine groups of potential leakage paths have been determined. The ventilation system has been found as the major source of expected leakage having 60 penetrations with size above 250 mm. Proposed modifications of the ventilation system include reduction of the number of inflow and suction valves, replacement of some valves with a better quality ones and installation of isolating valves. It is planned to transfer the experience and results of this study to the other WWER-440 units. 1 ref

PSB-VVER simulation of Kozloduy NPP 'loss of feed water transient'

Energy Technology Data Exchange (ETDEWEB)

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; Pavlova, M.P. [Institute for Nuclear Research and Nuclear Energy, Tzarigradsko Shaussee 72, Sofia 1784 (Bulgaria)]. E-mail: pavlova@inrne.bas.bg

2005-04-01

This paper provides a comparison between the PSB test facility experimental results obtained during the simulation of loss of feed water transient (LOFW) and the calculation results received by INRNE computer model of the same test facility. Integral thermal-hydraulic PSB-VVER test facility located at Electrogorsk Research and Engineering Center on NPPs Safety (EREC) was put in operation in 1998. The structure of the test facility allows experimental studies under steady state, transient and accident conditions. RELAP5/MOD3.2 computer code has been used to simulate the loss of feed water transient in a PSB-VVER model. This model was developed at the Institute for Nuclear Research and Nuclear Energy for simulation of loss of feed water transient. The objective of the experiment 'loss of feed water', which has been performed at PSB-VVER test facility is simulation of Kozloduy NPP LOFW transient. One of the main requirements to the experiment scenario has been to reproduce all main events and phenomena that occurred in Kozloduy NPP during the LOFW transient. Analyzing the PSB-VVER test with a RELAP5/MOD3.2 computer code as a standard problem allows investigating the phenomena included in the VVER code validation matrix as 'integral system effects' and 'natural circulation'. For assessment of the RELAP5 capability to predict the 'Integral system effect' phenomenon the following RELAP5 quantities are compared with external trends: the primary pressure and the hot and cold leg temperatures. In order to assess the RELAP5 capability to predict the 'Natural circulation' phenomenon the hot and cold leg temperatures behavior have been investigated. This report was possible through the participation of leading specialists from Kozloduy NPP and with the support of Argonne National Laboratory (ANL), under the International Nuclear Safety Program (INSP) of the United States Department of Energy.

Women in nuclear energy – motivation and prospects at Kozloduy NPP report

International Nuclear Information System (INIS)

Radneva, R.

2015-01-01

The report presents part of the study of the staff motivation at Kozloduy NPP plc, which is performed annually. A total of 25 factors have been considered, and for 8 of them the internal motivation characteristics have been discussed, while the remaining 17 factors determine the satisfaction from external motivation stimuli: positive ones (remuneration, bonuses, awards, etc.), as well as negative (little lead time, sanctions, punishments, excessive control in the performance of tasks, etc.). Women in the nuclear industry contribute to the unique image of nuclear organisations and are an especially valued asset. In the selection of staff for vacancies there is no sex discrimination, and it is increasingly becoming evident from the number of women employed in jobs considered until recently as typically male. The satisfaction from the measured Internal motivation factors concerning the women working at Kozloduy NPP is presented in this work.

Environmental monitoring of the Kozloduy NPP: 20 year experience

Energy Technology Data Exchange (ETDEWEB)

Aleksiev, A; Tsochev, S; Dimitrov, M; Avramov, V [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1996-12-31

The radiation monitoring system of the Kozloduy NPP is described and the assessment of the environmental impact of the power plant is presented. Measurements are carried out in 36 control points distributed in 3 areas: radiation protected area (3 km diameter), radiation controlled area (12 km) and surveillance area (100 km). Comparison of radiation monitoring data for 1993 with data recorded in the pre-operational period (1972-74) show that no significant changes can be detected in the activity of {sup 90} Sr and gross beta activity. An increase in Cs-137 activity (38 Bq/kg d.w. versus 7 Bq/kg d.w.) is found in the soil and bottom sediments in the Danube river, which is attributed to Chernobyl accident. The Kozloduy NPP operation is continuously monitored for release of artificial radionuclides by gaseous and liquid effluents. It is reported that the average population exposure in the 30 km area due to liquid effluents is 3-4.10{sup -4} man Sv/a. A system for automated continuous radiation monitoring in 10 control stations is available in case of radiation accidents. It is supplemented by a mobile laboratory. Meteorological measurements are carried out by automatic station MC-10 and a second station is under construction. 21 refs., 2 figs., 6 tabs.

Environmental monitoring of the Kozloduy NPP: 20 year experience

International Nuclear Information System (INIS)

Aleksiev, A.; Tsochev, S.; Dimitrov, M.; Avramov, V.

1995-01-01

The radiation monitoring system of the Kozloduy NPP is described and the assessment of the environmental impact of the power plant is presented. Measurements are carried out in 36 control points distributed in 3 areas: radiation protected area (3 km diameter), radiation controlled area (12 km) and surveillance area (100 km). Comparison of radiation monitoring data for 1993 with data recorded in the pre-operational period (1972-74) show that no significant changes can be detected in the activity of 90 Sr and gross beta activity. An increase in Cs-137 activity (38 Bq/kg d.w. versus 7 Bq/kg d.w.) is found in the soil and bottom sediments in the Danube river, which is attributed to Chernobyl accident. The Kozloduy NPP operation is continuously monitored for release of artificial radionuclides by gaseous and liquid effluents. It is reported that the average population exposure in the 30 km area due to liquid effluents is 3-4.10 -4 man Sv/a. A system for automated continuous radiation monitoring in 10 control stations is available in case of radiation accidents. It is supplemented by a mobile laboratory. Meteorological measurements are carried out by automatic station MC-10 and a second station is under construction. 21 refs., 2 figs., 6 tabs

Requalification of the steam supply systems of Units 3 and 4 of the Kozloduy NPP to a new model WWER-440/B-209M

International Nuclear Information System (INIS)

Iordanov, I.; Ourutchev, V.; Stoev, M.; Sabinov, S.

2001-01-01

In order to achieve significant advances in operational safety level, the project characteristics, the possibility of safety systems upgrading and operational conditions of Units 1 to 4 of the Kozloduy NPP were an object of very serious and in-depth analysis in the years 1990-2000. This systematic evaluation was initiated under the broad international concern resulted from the conclusions of IAEA missions held during 1990-1991 to assess the safety of the units. As a result of the efforts of the plant staff and many international experts the operational conditions, design safety and plant management were dramatically improved which resulted in bringing the plant to a new safety level. This review also developed such that the design safety features of Units 3 and 4 are significantly different from those units of the so-called V-230 group. The principle difference and advantages of Units 3 and 4 design were clarified and confirmed. A review process of the changed status of Units 3 and 4 safety was conducted in 1999-2000 with the help of IAEA experts and the experts of RISKAUDIT and WENRA. The process led to the conclusion that the significance of advantages of the safety level need to be encapsulated within a new safety case and the corresponding set of steps was combined as a 'Project for upgrading the Nuclear Steam Supply System of Units 3 and 4 of Kozloduy NPP to model WWER-440/B-209M'. The completion of the activities under this project is expected in 2002 following the major implementation phase during 2001/2002 units' outages. (author)

Seismic re-evaluation of Kozloduy NPP criteria, methodology, implementation

International Nuclear Information System (INIS)

Kostov, M.

2003-01-01

The paper describes some features of the methodology applied for seismic upgrading of civil structures at the site of the Kozloduy NPP. The essence of the methodology is the use of as-build data, realistic damping and inelastic reduction factors. As an example of seismic upgrading the analyses of units 3 and 4 are presented. The analyses are showing that for effective seismic upgrading detailed investigations are needed in order to understand the significant response modes of the structures. In the presented case this is the rotation of the attached flexible structures to the stiff reactor building. Based on this an upgrading approach is applied to increase the seismic resistance for the predominant motion. The second significant approach applied is the strengthening of the prefabricated element joints. Although it is very simple it allows use of the available element capacity. (author)

Boat sampling and inservice inspections of the reactor pressure vessel weld No. 4 at Kozloduy NPP, Unit 1

International Nuclear Information System (INIS)

Cvitanovic, M.; Oreb, E.; Mudronja, V.; Zado, V.; Bezlaj, H.; Petkov, M.; Gledatchev, J.; Radomirski, S.; Ribarska, T.; Kroes, B.

1999-01-01

The paper deals with reactor pressure vessel (RPV) boat sampling performed at Kozloduy Nuclear Power Plant, Unit 1, from August to November 1996. Kozloduy NPP, Unit 1 has no reactor vessel material surveillance program. Changes in the material fracture toughness resulting from the fast neutron irradiation which cannot be monitored without removal of the vessel material. Therefore, the main objective of the project was to cut samples from the RPV wall in order to obtain samples of the RPV material for further structural analyses. The most critical area, i.e. weld No. 4 was determined as a location for boat sampling. Replication technique was applied in order to obtain precise determination of the weld geometry necessary for positioning of the cutting tool prior to boat sampling, and determination of divot depth left after boat sampling and grinding of sample sites. Boat sampling was performed by electrical discharge machining (EDM). Grinding of sample sites was implemented to minimize stress concentration effects on sample sites, to eliminate surface irregularities resulting from EDM process, and to eliminate recast layer on the surface of the EDM cut. Ultrasonic, liquid penetrant, magnetic particles, and visual examinations were performed after grinding to establish baseline data in the boat sampling area. The project preparation activities, apart from EDM process, and the site organization lead was entrusted to INETEC. The activities were funded by the PHARE program of the European Commission. (orig.)

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

International Nuclear Information System (INIS)

Demireva, E.; Goranov, S.; Horstmann, R.

2004-01-01

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)

Features of the Kozloduy NPP management system

International Nuclear Information System (INIS)

2016-01-01

The Kozloduy NPP management system was built taking into account the specifics of the organizational structure and management of the Company, actual processes and practices, and is oriented towards future development, with the participation of all staff. Additional requirements integrated in the system that distinguish it from general industrial requirements of management systems are: priority of nuclear safety; safety culture; knowledge management including extraction and storage of 'hidden knowledge'; periodic self-assessments; use of graded response to the products and activities; use of 'conservative approach' in decision making;; possibilities for self learning and creating of a vision of 'leaders' and 'professional workers in nuclear energy

Influence of the Kozloduy NPP on the health state of personnel at a normal operation regime

International Nuclear Information System (INIS)

Bliznakov, V.

1995-01-01

Medical observation of the Kozloduy NPP personnel has been carried out for 20 years (1974-1993). The general disease incidence with temporary incapacity of the Kozloduy workers is lower than the general data for the country and workers at thermal power stations in particular. No cases of radiation injuries have been registered. The level of cumulative radiation doses varies from 50 to 620 mSv for the full working period of the personnel. Data about dependence of peripheral blood indicators on the cumulative dose are presented. It is concluded that the health state of the Kozloduy personnel is very good and does not indicate any specific pathology. 5 figs., 2 tabs

Influence of the Kozloduy NPP on the health state of personnel at a normal operation regime

Energy Technology Data Exchange (ETDEWEB)

Bliznakov, V [National Centre of Radiobiology and Radiation Protection, Sofia (Bulgaria)

1996-12-31

Medical observation of the Kozloduy NPP personnel has been carried out for 20 years (1974-1993). The general disease incidence with temporary incapacity of the Kozloduy workers is lower than the general data for the country and workers at thermal power stations in particular. No cases of radiation injuries have been registered. The level of cumulative radiation doses varies from 50 to 620 mSv for the full working period of the personnel. Data about dependence of peripheral blood indicators on the cumulative dose are presented. It is concluded that the health state of the Kozloduy personnel is very good and does not indicate any specific pathology. 5 figs., 2 tabs.

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

International Nuclear Information System (INIS)

Uruchev, V.; Vassilev, P.; Ivanova, A.; Sartmadjiev, A.

2005-01-01

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

Information on current status of equipment and activities for extension of NPP Kozloduy life time

International Nuclear Information System (INIS)

Pekov, B.

1995-01-01

The NPP Kozloduy personnel activities are described directed to undertake measures to overcome the difficulties entailed by equipment failures and human errors in order to avoid recurrent emergency events and to reduce their total numbers. 12 figs, 2 tabs

Determination and elimination of the reasons for increased control rod insertion time of the Kozloduy NPP WWER-1000

International Nuclear Information System (INIS)

Nikolov, K.

1996-01-01

The emergency insertion speed of the control rod upon reactor shutdown is of crucial importance for reactor safety. The designed insertion time for WWER-1000 reactors should be in the limits 1,5 to 4 s. Having in mind some data about increased insertion times of WWER-1000 type reactors in Russia and Ukraine, a practice of measuring this parameters during each planned outage of the Kozloduy NPP Unit 6 is introduced. Some technical improvements of the fuel assembly are made in order to reach the nominal parameters of the unit

Some aspects of correction additions optimisation of water chemistry regime of Kozloduy NPP power units 3 and 4

International Nuclear Information System (INIS)

Topalova, I.

2005-01-01

Optimization of the water-chemistry regime is a major corrective measure for minimization of the corrosion processes of the nuclear power unit equipment. Research done in NPP Kozloduy III - IV power units concerning the migration of the corrosion products in the water of secondary circuit as well as the connection between corrosion processes and fluctuation in parameters of the applied water-chemistry regime are reported. Analysis of the dependences obtained lead to conclusions for optimization of the water chemistry regime of secondary circuit and minimization of the corrosion processes and improvement of corrosion condition of metal surfaces. The research is done for the circuit of each of the 8 turbines of the two power units for a period of 10 days. Data received is quantitatively representative /40-50 points/ for performing of analysis and reaching certain conclusions for the water chemistry regime and development of corrosion processes. Dependence of iron and copper concentration in the work medium on the pH, ammonia and hydrazine concentration as well as the dependence of pH on ammonia concentration in case of different quantity and composition of corrosion products on the different power units' equipment metal surfaces are shown. (author)

Non-destructive control at the Kozloduy NPP; Nerazrushayushchij kontrol` v AEhS `Kozloduy`

Energy Technology Data Exchange (ETDEWEB)

Mikhovsky, M [Institute of Mechanics, Bulgarian Academy of Sciences, Sofia (Bulgaria); Skordev, A [SIME-CONTROL, Sofia (Bulgaria); Nichev, V; Tsokov, P; Popova, N [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1996-12-31

A program for technical diagnostics using non-destructive methods is being carried out at the Kozloduy NPP. The main target is to test mechanical equipment integrity (metal control, mechanical stress control, etc.) as well as electrical equipment. Computer methods and simulation are widely used in program implementation. Non-destructive testing is based on methods involving optical, radiation, ultrasonic and magnetic processes. Control procedures are standardised in special technological documents and one of them is described as an example. It refers to ultrasonic control of the austenitic steel welds of the WWER-440 piping system (DU-500). Graphic representing the microstructure of the welds, the distribution of surface ultrasonic wave and the longitudinal and vertically polarised perpendicular waves are presented. 6 refs. 8 figs.

Development of safety culture at Kozloduy NPP: The role of the regulatory body

International Nuclear Information System (INIS)

Miliovsky, Ventzislav

2002-01-01

An evolution is made upon external factor that accompany the development of safety culture at Kozloduy NPP (KNPP). The two basic stages and the major results achieved independently and with external assistance were considered in the process of development of safety culture. The areas in which the regulatory body insists on having active participation were defined. (author)

Seismic safety review mission to assist in the evaluation of the design of seismic upgrading for Kozloduy NPP. Sofia, Bulgaria, 19-23 October 1992

International Nuclear Information System (INIS)

Ma, D.; Prato, C.; Godoy, A.

1992-10-01

A seismic Safety Review Mission to assist in the evaluation of the design of seismic upgrading for Kozloduy NPP was performed in Sofia from 19-23 October 1992. The objectives of the mission were to assist the Bulgarian authorities in: the evaluation of the floor response spectra of the main buildings of units 1-4 at Kozloduy NPP, calculated for the new defined seismic parameters at site (Review Level Earthquake - RLE); the evaluation of the remedial and strengthening measures proposed for the seismic upgrading of the pump house and diesel generator buildings to the new defined RLE. This mission completed the scope of previous IAEA mission - BUL/9/012-18b - (see Report 3262) performed from 3-7 August 1992, with regard to tasks which were not evaluated at that time because they had not been finished. 2 tabs

Environmental radioactivity of the Danube basin in the vicinity of the Kozloduy NPP (July 1994)

Energy Technology Data Exchange (ETDEWEB)

Badulin, V; Zlatanova, R; Botsova, L; Mireva, Z [National Centre of Radiobiology and Radiation Protection, Sofia (Bulgaria)

1996-12-31

Analytical results from radiation monitoring carried out at the Kozloduy NPP area are reported. Sampling of water, sediment, soil and grass for beta and gamma activity has been done in 13 points at distances ranging from 6 to 90 km from the plant. The comparison of data with the values for the previous year does not show any significant variations in radioactivity. The values of {sup 90}Sr activity in river water are less than 10 mBq/l, in river bottom sediment - less than 2 Bq/kg, in soil - less than 4 Bq/kg and in grass -below 8 Bq/kg. Activity of Cs-137 is highest in river bottom sediment - 6-43 Bq/kg which is attributed to the Chernobyl accident. It is concluded that the radioactive effluents and atmospheric releases from the Kozloduy NPP do not produce any noticeable changes in environmental radioactivity caused by the global fallout and the Chernobyl accident. 9 figs., 1 tab.

Three years re-use of low burned fuel assemblies from units 1 and 2 in core loading of units 3 and 4 WWER-440 at Kozloduy NPP

International Nuclear Information System (INIS)

Stoyanova, I.; Antov, A.; Spasova, V.

2006-01-01

At the end of 2002 Units 1 and 2 of Kozloduy NPP were shutdown before the end of their designed lifetime. This left a large number of assemblies yet with a significant energy resource. In 2003, 43 assemblies from Unit 1 and 55 assemblies from Unit 2 are loaded in the cores of Units 3 and 4 respectively. In 2004, new 49 assemblies from Unit 1 and new 55 assemblies from Unit 2 are loaded in the cores of Units 3 and 4 respectively. In 2005, the next new 25 assemblies from Unit 1 and 66 assemblies from Unit 2 are loaded in the cores of Units 3 and 4 respectively. The realized core loadings of Units 3 and 4 are illustrated. The large number of low burned assemblies after the shut down of Units 1 and 2 and their utilization during 4 consecutive cycles in the cores of Units 3 and 4 both do not permit to obtain in the last 3 cycles the typical mean burn up 35-36 MWd/kg U of 3.6% discharged assemblies

Drawings: Kozloduy NPP

International Nuclear Information System (INIS)

Boyadjiev, Z.

1995-01-01

This paper includes drawings of Kozloduy nuclear power plant needed for study for the seismic analysis and testing. It covers the list and schemes of safety and safety related systems for normal operation as well as protection and control systems

The Kozloduy project management unit

International Nuclear Information System (INIS)

Carnes, W.S.; Gros-Gean, P.; Demireva, E.

2004-01-01

The Project Management Unit (PMU) has been established in support to the Kozloduy NPP decommissioning department. It is comprised of a Consortium of the British Nuclear Group, EDF and subcontractor ENPRO Consult. It is responsible for the management of seven projects (a facility for dry storage of spent fuel; equipment to treat low activity liquid radioactive waste; provision of physical separation of the plant systems and areas to be decommissioned from the ones in operation; equipment to decontaminate and clean pools and large tanks; a facility to provide high volume reduction of solid radioactive wastes and retrieval and conditioning of ion exchange resins and other sorbents; equipment to provide measurement for the free-release of materials and components; a facility for personnel monitoring, decontamination and clothes changing for work outside of the normal radiological control areas) that will be used in support of the KNPP decommissioning process. The projects will be tendered in compliance with the European Bank for Reconstruction and Development requirements

Behaviour of NPP Kozloduy (Bulgaria) during the three strong Vranchea earthquakes

International Nuclear Information System (INIS)

Sachanski, S.; Krutzik, N.; Sachanski, G.

1991-01-01

Following the new tendency a coordinated program with IAEA-Vienna for increasing of NPP Kozloduy seismic safety is in realisation. To check the real characteristics of 440 MW blocks, to establish more realistic mathematical model and response of structure is purpose of this study. The revaluated and increased the design peak ground acceleration with 40 % needs additional analysis of the structures and equipment. Space mathematical model and three component seismic excitation, represented with power spectra density function, are under consideration for revaluation of seismic safety. (author)

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)

David, M.; Shibata, H.; Stevenson, J.D.; Godoy, A.; Gurpinar, A.

1992-11-01

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

Kozloduy NPP WWER-440/230 reactor pressure vessel radiation lifetime

Energy Technology Data Exchange (ETDEWEB)

Vodenicharov, S [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. po Metaloznanie i Tekhnologiya na Metalite; Kamenova, Tz [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. po Metaloznanie i Tekhnologiya na Metalite; Tzokov, P; Videnov, A [Kombinat Atomna Energetika, Kozloduj (Bulgaria); Pekov, B [Committee on the Use of Atomic Energy for Peaceful Purposes, Sofia (Bulgaria)

1996-12-31

The processes of metal embrittlement induced by neutron irradiation embrittlement (NIE) and neutron re-irradiation embrittlement (NRE) of the rector pressure vessel (RPV) are investigated. Radiation lifetime is calculated using two approaches for re-embrittlement: a conservative law and a lateral shift of the critical transition temperature curve after neutron irradiation. In order to prevent NIE the following measures have been taken at the Kozloduy NPP: loading of dummy elements into core periphery; heating the water for emergency core cooling to 55{sup o} C; fast acting valves in the main steam piping, etc. The critical embrittlement temperature, the residual part of temperature shift and the radiation lifetime have been calculated for units 1 - 4 using the two approaches and updated information on P and Cu impurities content. It is concluded that if the lateral re-embrittlement law is adopted and the P content does not exceed 0.05%, all RPV should reach their design lifetime. The NIE in WWER-440/230 is related to C and P content in the weld 4 and is negligible for the Unit 4 in particular, which has low impurities content. In order to reach the design lifetime of the Units 1 - 3 it is necessary to install MSIV. A verification of chemical composition of the Unit 1 RPV weld 4 metal is recommended. 7 refs., 3 figs., 6 tabs.

Kozloduy NPP WWER-440/230 reactor pressure vessel radiation lifetime

International Nuclear Information System (INIS)

Vodenicharov, S.; Pekov, B.

1995-01-01

The processes of metal embrittlement induced by neutron irradiation embrittlement (NIE) and neutron re-irradiation embrittlement (NRE) of the rector pressure vessel (RPV) are investigated. Radiation lifetime is calculated using two approaches for re-embrittlement: a conservative law and a lateral shift of the critical transition temperature curve after neutron irradiation. In order to prevent NIE the following measures have been taken at the Kozloduy NPP: loading of dummy elements into core periphery; heating the water for emergency core cooling to 55 o C; fast acting valves in the main steam piping, etc. The critical embrittlement temperature, the residual part of temperature shift and the radiation lifetime have been calculated for units 1 - 4 using the two approaches and updated information on P and Cu impurities content. It is concluded that if the lateral re-embrittlement law is adopted and the P content does not exceed 0.05%, all RPV should reach their design lifetime. The NIE in WWER-440/230 is related to C and P content in the weld 4 and is negligible for the Unit 4 in particular, which has low impurities content. In order to reach the design lifetime of the Units 1 - 3 it is necessary to install MSIV. A verification of chemical composition of the Unit 1 RPV weld 4 metal is recommended. 7 refs., 3 figs., 6 tabs

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

International Nuclear Information System (INIS)

Demireva, E.; Goranov, S.; Horstmann, R.

2004-01-01

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)

An opportunity for capacity up-rating of 1000 MW steam turbine plant in Kozloduy NPP

International Nuclear Information System (INIS)

Popov, D.

2005-01-01

In connection with earlier and forced decommissioning of the Kozloduy NPP units 1 - 4, an alternative has to be found in order to substitute these capacities. As a reasonable options, capacity up-rating of 1000 MW steam turbine plants without nuclear reactor thermal capacity increase, is investigated in the present study. The cooling water for these units is delivered by Danube river. The cooling water temperatures substantially decrease during the winter months. These changes create an opportunity for steam back end pressure reduction. It was found that when the cooling water temperature decreases from 15 0 C to 3 0 C, the steam back end pressure is on the decrease of from 3.92 kPa to 2.3 kPa. As a result capacity of the plant could be raised up to 50 MW without any substantial equipment and systems change

Modeling of behaviour of main type personnel in Kozloduy NPP during different operational conditions

International Nuclear Information System (INIS)

Hristova, R.; Kalchev, B.

2000-01-01

The subject of this article is the personnel behavior and initiating events modeling, based on the operational experience in the NPP 'Kozloduy' initiating events reports. The development of models on qualitative information is much more difficult comparing the quantitative modeling. The modelling process is based on the artificial intelligence theory and methods including knowledge base and inference machine in the frame of logical models and semantic networks. (author)

Regulatory approach to NPP ageing in Bulgaria

International Nuclear Information System (INIS)

Vassilev, D.

2000-01-01

In this contribution summary information of Kozloduy NPP units is presented. The nuclear legislation, regulatory approach for managing safety aspects on NPP ageing, short term programme, complex programme PRG'97 ant other aspects of ageing management are discussed

Cs 137 and Sr 90 content in the Kozloduy NPP environment; Soderzhanie 137Cs i 90Sr v obektakh okruzhayushchej sredy v rajone AEhS `Kozloduy`

Energy Technology Data Exchange (ETDEWEB)

Karaivanova, R; Totseva, R; Badulin, V; Zlatanova, R; Fajtondzhieva, K [National Centre of Radiobiology and Radiation Protection, Sofia (Bulgaria)

1996-12-31

The radioactivity status of soil and plant samples collected in the 12 km controlled zone surrounding Kozloduy has been investigated in the period 1990-1993. The average annual concentrations of Sr-90 and Cs-137 are compared to the values taken at 40 km distance. Cs-137 has in general higher concentrations in soil samples from the NPP close surroundings - e.g. 50-55 Bq/kg in 1992 versus 2-2.5 Bq/kg for Sr-90. Radionuclide concentrations in grass do not differ significantly from the data at 40 km distance. It is concluded that the average annual doses follow the radionuclide dynamics in the global fallout and the effect of Kozloduy operation can not be separated from the background radioactivity status. 4 refs., 21 figs.

Modernization of electrical systems in NPP Kozloduy unit 5 and 6. Feedback of experience

International Nuclear Information System (INIS)

Stinshoff, H.

2005-01-01

In the frame of the modernization program for the nuclear power plant Kozloduy unit 5 and 6 Framatome ANP has implemented measures to increase the safety and availability of the electrical systems. The hardware installation is scheduled in the refueling outages of the years 2003 to 2005. In this paper the following items are presented: 1) an overview of the modernization measures; 2) some important technical features of the new equipment and diagnostic measures; 3) feedback of experience

Full-scale and in-situ tests on the structures and sites of Kozloduy and Belene NPPs

International Nuclear Information System (INIS)

Simeonov, S.

1995-01-01

This paper includes a detailed list of full scale and in-situ tests that were carried out on the structures and the sites of Kozloduy and Belene nuclear power plants. This involves reactor buildings and turbine halls of the five Kozloduy units, foundations of deaerator and turbine of unit 1, boreholes near channels for additional technical water supply, boreholes near units 2, 3 and 5, boreholes near the concrete center. Special measurement profile and gravel embankment of Belene NPP are included as well

Development of a methodology for maintenance optimization at Kozloduy NPP

International Nuclear Information System (INIS)

Kitchev, E.

1997-01-01

The paper presents the overview of a project for development of an applicable strategy and methods for Kozloduy NPP (KNPP) to optimize its maintenance program in order to meet the current risk based maintenance requirements. The strategy in a format of Integrated Maintenance Program (IMP) manual will define the targets of the optimization process, the major stages and elements of this process and their relationships. IMP embodies the aspects of the US NRC Maintenance Rule compliance and facilitates the integration of KNPP programs and processes which impact the plant maintenance and safety. The methods in a format of IMP Instructions (IM-PI) will define how the different IMP stages can be implemented and the IMP targets can be achieved at KNPP environment. (author). 8 refs

An application of low leakage loading pattern to reduce fast neutrons. Fluence on WWER-440 reactor pressure vessel in Kozloduy NPP

International Nuclear Information System (INIS)

Haralampieva, Tz.; Antonov, A.; Monev, M.

2001-01-01

The neutron exposure of a reactor pressure vessel (RPV) is one of the key factors that have to be quantified and assess reliably to provide plant life assurance and for an extension to operational life. This paper summarizes the principal methods that are used in core design optimisation for WWER-440 reactors in NPP-Kozloduy in order to reduce flux of fast neutrons at the RPV. Results of fast neutron fluence changes during the all last cycles of units 1-4 with WWER-440 reactors are considered (Authors)

A model for severe accidents management of WWER 440 at Kozloduy NPP

International Nuclear Information System (INIS)

Genovski, I.; Bonev, B.; Velev, V.; Grigorov, A.; Filipov, L.

2006-01-01

In order to reduce the residual risk associated with hypothetical severe nuclear accidents, systems and components for filtered containment venting and H2 reduction were implemented in the Kozloduy NPP units 3 and 4. The system technologies developed have to fulfill the following main tasks: 1) Creating a new pressure barrier system to confine the activity inventory by maintaining a slight containment sub-atmospheric pressure thereby preventing any relevant unfiltered activity releases. 2) Retaining a great extend of the airborne activity in the liquid phase of the venturi scrubber unit and return these activity back into the containment. 3) Controlling the containment atmosphere H2 gas mixture to prevent fast deflagration that may jeopardize the containment integrity. To meet above mentioned requirement a system was developed, consisting of a venturi scrubber unit which comprises a high speed long venturi section, a metal fibre filter section and molecular sieve. The system is operated by a turbo blower unit supplied with electrical power from the unaffected unit. The system keeps a slight sub-atmospheric pressure (approx. 5 - 10 mbar) in the containment with the purpose to minimize the uncontrolled radioactive release from the containment to the environment. The final analysis showed that the containment performance in combination with above mentioned countermeasures could be increased significantly and the impact to the environment is minimized

Floor response spectra of WWER-1000, NPP Kozloduy generated from local seismic excitation

International Nuclear Information System (INIS)

Bojadziev, Z.; Kostov, M.

1996-01-01

The seismic review level characteristics for the Kozloduy NPP site were set to 0.2 g and a respective free field acceleration response spectra were derived after a profound site conformation project. Accordingly a separate investigation is recommended for local seismic excitation. The goals of the analyses are: to define the seismic motion characteristics from local seismic sources; to perform structural analyses and in-structure spectra generation for local seismic excitation; and to compare the forces (spectra) from local events with those generated as seismic design review basis

Monitoring and evaluation of the health status of workers from the Kozloduy NPP for the period 2011-2013

International Nuclear Information System (INIS)

Negoycheva, Krasimira; Chobanova, Nina; Peyankov, Her; Miltchev, Audrey; Djounova, Jana

2015-01-01

The aim of this study was to establish the impact of occupational exposure on workers in the Kozloduy NPP through monitoring and evaluation of their health status. The study involved 302 persons from the NPP for the period 2011-2013. Based on the protocol for individual monitoring, cumulative doses of the respondents are in the range of 0.1 to 588 mSv. The probability of the occupational exposure to be a reason for the diagnosed malignant diseases has been determined (Probability of Causation is henceforth denoted as PC)

Experience from transportation of irradiated WWER-440 fuel assemblies at Kozloduy NPP site after a short cooling time

International Nuclear Information System (INIS)

Stoyanova, I.; Kamenov, A.; Byrzev, L.; Christoskov, I.

2003-01-01

The presented results from the computation and analysis of the radiation characteristics of the irradiated fuel assemblies by the date of their transportation according to the selected loading patterns of the VSPOT cask and following the modified technology of transportation, i.e. without replacement of the pool solution by pure condensate, as well as the corresponding experimental results, confirm the applicability of the newly introduced safety criterion for the selection of a loading pattern of the cask with irradiated fuel assemblies after a short cooling time. The comparison between measured and computed surface dose rates shows that during the procedure of transfer of irradiated fuel assemblies from the pools of Units 1 and 2 to the pools of Kozloduy NPP Units 3 and 4 all safety limits, incl. the radiation protection requirements, were met

Modeling of coherent heat and mass-exchange phenomena for a specter of primary circuit leaks in a NPP with WWER-1000 type reactor

International Nuclear Information System (INIS)

Stanev, I.; Mladenova, S.; Hadjiev, V.

2004-01-01

Subject of study are the inter-relations between the primary leak parameters, the containment pressure and the functioning of the WWER-1000/V320 plant systems. The model includes systems for normal operation and safety systems, which are actuated in the initial stage of the accident. The studied specter of primary leaks includes diameters from 10 to 60 mm. The model is based on the design features of unit 5 in NPP Kozloduy. This paper presents a fragment of the work, performed jointly by Atoma Consult Ltd and NPP Kozloduy Plc on the validation of the symptom oriented emergency operation procedures for units 5 and 6 in NPP Kozloduy. (authors)

Probabilistic safety analysis of the Kozloduy NPP units 1-4 (WWER-440/230) using independent emergency feedwater system; Veroyatnostnyj analiz bezopasnosti I-IV blokov AEhS `Kozloduy` s reaktorami tipa WWER-440 (V 230) pri vklyuchenii nezavisimoj sistemy avarijnoj podpitki PG

Energy Technology Data Exchange (ETDEWEB)

Kalchev, B; Marinov, M; Dimitrov, B; Avdzhiev, K [Energoproekt, Sofia (Bulgaria)

1996-12-31

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.

Improvement of the reliability of the emergency diesel generators and their protections as a part of the modernization program for units 5 and 6 of the Kozloduy NPP

International Nuclear Information System (INIS)

Bogdanov, D.

2003-01-01

The measure 'Improvement of the reliability of the emergency diesel generators and their protections' 28411 is part of the modernization program for Units 5 and 6 of Kozloduy NPP. The scope of the measure includes complete change of the I and C system, the local control panels, the technological and electrical protections of the DG set, the excitation system and some of the power distribution switchboards. The new I and C system will be Teleperm XS type, produced by Framatome ANP, the power distribution switchboards type Sivacon, the excitation system Thyripart, and the electrical protection and synchronization system will be provided by Siemens. The purpose of the measure is to increase the availability, maintainability and to improve the reliability of the DG sets

Information technologies in radioactive waste management, applied in NPP-Kozloduy, Bulgaria

International Nuclear Information System (INIS)

Jeliazkov, J.; Jeliazkova, L.; Atanasov, Sv.

1994-01-01

Radioactive waste (RAW) management in NPP is a complex problem, that can be considered as a combination of sub problems, for example scientific, administrative, social, economical, etc. The separate examination of these sub problems does not lead to creation of overall system for optimal RAW management. There's no doubt that such an administrative system, supported by information technologies, should present in every one existing and planned nuclear power plant to optimize its operation as a whole, not only separate elements. The aim is to avoid the fallacy of the single and the complex. This paper presents a basic part of the whole information management system as defined above that concerns RAW management. The information management system is prepared for NPP-Kozloduy, Bulgaria by means of modern concepts and technological schemes and is aimed to help the administrative personnel in this very important activity - RAW management. On the base of objective data about the available waste and prognoses about arisings in the future, on the base of chosen technologies and equipment the system gives multi-variant plan for treatment, processing and disposal of waste, after the choice of a variant it monitors its application in the practice

Neutron fluence determination for operation effectiveness assessment and prediction of WWER pressure vessel lifetime at the Kozloduy NPP

Energy Technology Data Exchange (ETDEWEB)

Apostolov, T; Ilieva, K; Belousov, S; Petrova, T; Antonov, S; Ivanov, K; Prodanova, R; Penev, I; Taskaev, E [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. za Yadrena Izsledvaniya i Yadrena Energetika; Ivanov, I; Tsokov, P; Nelov, N; Lilkov, B; Tsocheva, V; Monev, M; Velichkov, V; Kharalampieva, Ts [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1996-12-31

Embrittlement processes in reactor pressure vessel (RPV) metal have been investigated by neutron dosimetry. A software package for fluence calculations has been developed and used for evaluation of the accumulated neutron fluence, the critical temperature of radiation embrittlement and the RPV lifetime. A digital reactivity meter DR-8 has been introduced for continuous neutron fluence monitoring. Estimates of the neutron fluence and the radiation state of all 6 units of the Kozloduy NPP are presented. The Unit 4 RPV is in the best state regarding metal embrittlement, while the Units 2 and 3 can be safely operated up to the end of their design lifetime only using dummy cassettes. The neutron fluence accumulation in the Unit 1 RPV is quite big and can not be reduced with annealing. Activity measurements of the Unit 1 internal wall shavings are made after the 14-th cycle which show a good agreement with calculated values (1.10{sup 5} Bq/g). The critical embrittlement temperature of the Units 1 - 4 is estimated as a function of the working cycles. 11 figs., 1 tab.

Content of Strontium-90 in soils and sediments from the vicinity of the Kozloduy NPP for the period 2011-2012

Energy Technology Data Exchange (ETDEWEB)

Kamenova-Totzeva, R.; Kotova, R.; Tenev, J.; Ivanova, G.; Badulin, V. [Public Exposure Monitoring Laboratory, National Centre of Radiobiology and Radiation Protection, Sofia (Bulgaria)

2013-07-01

The National centre of radiobiology and radiation protection (NCRRP) – Sofia has carried out periodic radiation environmental monitoring and control of the region since the pre-operational period of the Nuclear power plant Kozloduy. The latest analytical results of the radiation monitoring for the period 2011- 2012 are described in this article. The object of study is the content of Strontium-90 in soils and bottom sediment samples at 17 points located from 6 to 90 km from the Kozloduy NPP. Obtained results of the investigation and analyses for the period 2011-2012 are shown in tables and figures. Annual results are compared with data from previous years as well as with data from the pre-operational period. (author)

Status and operational experience report of spent fuel storage facility in Kozloduy NPP for the period 1990 - 1994

Energy Technology Data Exchange (ETDEWEB)

Kalimanov, M [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1994-12-31

Spent Fuel Storage Facility (SFSF) of Kozloduy NPP is designed for a long-term storage of 4920 spent fuel assemblies which are generated by all units for ten year operational period. The assemblies are stored in SFSF after 3 year storage in the reactor cooling pool. The SFSF operational safety is ensured by a number of strictly followed regulations related to: arrangement of the assemblies and conditions at which they are stored; transportation of the assemblies to the facility; residual heat removal; quality of the water used in the storage pool; water temperature and level control. Two independent groups of experts have carried out investigations to study the building safety. Their reports have been considered and accepted by the council of the Ministry of Environment which was the final step in licensing the SFSF.

Radio ecological monitoring of soils within the region of Kozloduy NPP

International Nuclear Information System (INIS)

Naidenov, Ilko; Tsibranski, Rusiyan; Avramov, Valentin; Popov, Lubomir

2005-01-01

The main approach of assessing the radio ecological impact of nuclear power plants is systematic monitoring of major environmental components, status indicators and indicators on the dynamics of radiation status and those appearing as an inseparable part of the food chain for radioactivity intake by humans. Such ecological components are air, water, soil, plants, agricultural products - grain-fodder crops, meat, milk etc.- within NPP areas. All of these components participate directly or indirectly into the internal irradiation of human body, as different forms of intake from land and water ecosystem. The accumulation of natural and artificial radionuclides in main ecological components and its analysis are subject of a continuous scientific interest and research, and are mandatory part of the scope of control in the ecological monitoring programs. Modern high-sensitive methods, such as gamma spectrometry, radiochemical separation, radiometry of radiostrontium, alpha spectrometry of trans-uranium elements, etc., are being used for laboratory radiation analyses. Along with the monitoring of radiation gamma background of air and water, that is reasonably the largest in its volume and frequency in the ecological programs, research and radioactivity of soils is of high significance. The interest to the radiation status of soils is justified by the fact that they are the 'ecological stamp of time' and they give valuable information on the history and origin of radioactive contaminations. Radioactivity of soils within the region of Kozloduy NPP has been a subject of detailed and systematic research since the commissioning of the plant in 1974. The monitoring conducted by EML covers the region that is divided into three areas in order to be able to localize possible radiation impact by KNPP - 3 km, 12 km, and 100 km. Samples are taken and analysis of soils are made at 36 control points within the 100 km area of observation. An issue of great interest is the content of

Radio ecological monitoring of soil within the region of Kozloduy NPP

International Nuclear Information System (INIS)

Naidenov, I.; Tsibranski, R.; Avramov, V.; Popov, L.; Naidenov, Ilko; Tsibranski, Rusiyan; Avramov, Valentin; Popov, Lubomir

2005-01-01

Full text: The main approach of assessing the radio ecological impact of nuclear power plants is systematic monitoring of major environmental components, status indicators and indicators on the dynamics of radiation status and those appearing as an inseparable part of the food chain for radioactivity intake by humans. Such ecological components are air, water, soil, plants, agricultural products - grain-fodder crops, meat, milk etc.- within NPP areas. All of these components participate directly or indirectly into the internal irradiation of human body, as different forms of intake from land and water ecosystem. The accumulation of natural and artificial radionuclides in main ecological components and its analysis are subject of a continuous scientific interest and research, and are mandatory part of the scope of control in the ecological monitoring programs. Modern high-sensitive methods, such as gamma spectrometry, radiochemical separation, radiometry of radiostrontium, alpha spectrometry of trans-uranium elements, etc., are being used for laboratory radiation analyses. Along with the monitoring of radiation gamma background of air and water, that is reasonably the largest in its volume and frequency in the ecological programs, research and radioactivity of soils is of high significance. The interest to the radiation status of soils is justified by the fact that they are the 'ecological stamp of time' and they give valuable information on the history and origin of radioactive contaminations. Radioactivity of soils within the region of Kozloduy NPP has been a subject of detailed and systematic research since the commissioning of the plant in 1974. The monitoring conducted by EML covers the region that is divided into three areas in order to be able to localize possible radiation impact by KNPP - 3 km, 12 km, and 100 km. Samples are taken and analysis of soils are made at 36 control points within the 100 km area of observation. An issue of great interest is the

Task 24: Dynamic analysis of Kozloduy NPP unit 5 structures: Reactor building

International Nuclear Information System (INIS)

Zola, M.

1999-01-01

This report refers to the activities of a sub-contract to the Project RER/9/046, awarded to ISMES by the International Atomic Energy Agency (IAEA) of Vienna, to compare the results obtained from the experimental activities performed under previous contract by ISMES with those coming from analytical studies performed in the framework of the Coordinated Research Programme (CRP) on 'Benchmark Study for the Seismic Analysis and Testing of WWER-type Nuclear Power Plants' by other Institutions, relevant to Kozloduy Unit 5 reactor building. After a brief introduction to the problem in Chapter 1, the identification of the comparison positions and reference directions is given in Chapter 3. A very quick description of the performed experimental tests is given in Chapter 4, whereas the characteristics of both experimental and analytical data are presented in Chapter 5. The data processing procedures are reported in Chapter 6 and some simple remarks are given in Chapter 7. (author)

Determination of neutron fluence and radiation brittleness temperature of WWER-440 and WWER-1000 pressure vessels in Kozloduy NPP

International Nuclear Information System (INIS)

Ilieva, K.; Apostolov, T.; Belousov, S.; Petrova, T.; Antonov, S.; Ivanov, K.; Prodanova, R.

1993-01-01

In Units 1-4 of Kozloduy NPP (WWER-440/230), the weld 4 of RPV undergoes the most severe irradiation embrittlement. Neither witness-samples, nor detectors are designed for these reactors. Transport calculations of fast neutron fluence on WWER-440 RPV and ex-vessel measurements by threshold activation detectors are the primary means for adequate assessment of metal state and for prognosis concerning the reactor life span. In WWER-1000 reactors (Units 5-6) the maximum neutron fluence occurs on the weld 3. The systematical observation of metal state is performed through witness-samples and threshold activation detectors ( 54 Fe (n,p), 63 Cu (n,α), 93 Nb (n,n')) placed above the reactor top edge and at the first vessel ring level. There are big differences in energy spectrum and integral neutron flux falling onto the weld 3, the RPV base metal and the staff detectors. This requires additional neutron measurements in the air gap between the RPV and the thermal insulation. (author)

Experience from the transportation of irradiated WWER-440 fuel assemblies at the Kozloduy NPP site after a short cooling time

International Nuclear Information System (INIS)

Stoyanova, I.; Kamenov, A.; Byrzev, L.; Christoskov, I.

2003-01-01

Results from the analysis and experimental verification of the radiation and shielding characteristics of non-standard loading patterns of the VSPOT transport cask used for transportation of irradiated fuel assemblies after a short cooling time (120 180 days) on the site of the Kozloduy NPP are presented. An additional safety criterion related to the introduced modifications to the standard procedure of using the transport cask is formulated and discussed (Authors)

Application of modified version of SPPS-1 - HEXAB-2DB computer code package for operational analyses of fuel behaviour in WWER-440 reactors at Kozloduy NPP

Energy Technology Data Exchange (ETDEWEB)

Kharalampieva, Ts; Stoyanova, I; Antonov, A; Simeonov, T [Kombinat Atomna Energetika, Kozloduj (Bulgaria); Petkov, P [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. za Yadrena Izsledvaniya i Yadrena Energetika

1994-12-31

The modified version of SPPS-1 code called SPPS-1-HEXAB-2DB was applied for the purposes of the operational analysis and power peaking factors and reactor core critical parameters predictions of WWER-440s. The results of the calculations performed by the use of SPPS-1-HEXAB-2DB code and the corresponding parameters obtained from experiments at Kozloduy NPP WWER-440s as well as the results of fuel rod power distribution are presented. The method of operation simulation of reactor core with 349 assemblies (Unit 4) and with 313 fuel assemblies and 36 dummy fuel assemblies (Unit 1) is outlined. The modified code calculates not only fuel burnup and Pm-149 and Sm-149 concentrations distributions but also the space distribution of I-135 and Xe-135 concentrations. In this way it makes possible to perform the reactor operation simulation during the immediate periods after the reactor start-up or shut-down and to predict the critical reactor core parameters during transients. The results obtained show that SPPS-1-HEXAB-2DB code describes adequately the reactor core status. The new SPPS-1 code algorithm for estimation of assembly-wise power peaking factors distribution in reactor core is also described. The new code provides an option for checking the correctness of reactor core symmetry. The experience from the use of the modified SPPS-1-HEXAB-2DB code system confirms the provision of improved availability of operational analysis, prediction of Kozloduy NPP WWER-440s safe operations and fuel behaviour estimation. 14 tabs., 4 figs., 5 refs.

Seismic response and resistance capacity of 'as built' WWER 440-230 NPP Kozloduy: Verification of the results by experiments and real earthquake

International Nuclear Information System (INIS)

Sachanski, S.

1993-01-01

Although Kozloduy NPP units 1 and 2 were not designed for earthquakes they have withstood successfully the Vrancea Earthquake in 1977 with sire peak ground acceleration of 83 sm/s 2 . Both units as well as units 3 and 4 were later recalculated for maximum peak acceleration of 0.1 g. According to values calculated by two-dimensional model, in 1980 reactor buildings had sufficient earthquake resistance capacity for the accepted design seismic excitation. The non symmetric design of WWER-440 structures in plan and elevation, the large eccentricity between the center of rigidities and masses as well as technological connections between the separate substructures and units led to complicated space response and rotational effects which cannot be calculated by two-dimensional models. Three dimensional detailed 'as built' mathematical models were established and verified by series of experiments and real earthquake for: detailed analysis of 'as built' structural response, comparing the results of two and three dimensional models, detailed analyses of seismic safety margins

Analysis of buried pipelines at Kozloduy

International Nuclear Information System (INIS)

Asfura, A.

1999-01-01

This paper describes the analysis of the buried pipelines at Kozloduy NPP. It involves the description of the studied pipelines, their properties, a detailed description of the methodology applied, and the evaluation of the soil strain field as well as the graphical representation of the results obtained

Probability safety assessment of the Kozloduy-5 and Kozloduy-6 reactors

Energy Technology Data Exchange (ETDEWEB)

Boyadzhiev, A; Manchev, B [Risk Engineering Ltd., Sofia (Bulgaria)

1996-12-31

A probability safety assessment (PSA) of Level 1 (assessment of plant failures leading to the determination of core damage frequency) has been carried out for the NPP Kozloduy Units 5 and 6 (reactors WWER-1000). The scope of the study includes all significant accident initiators including seismic (earthquake) and fire initiators. Event trees for all initiators and fault trees for front line systems, support systems and major safety systems have been built. A distribution of the different initiators has been established as follows: internal initiators - 85%, seismic initiators - 5%, fire initiators- 10%. The loss of offsite power was identified as main contributor from the internal initiators with frequency 1,1.10{sup -4}/y. It is concluded that the safety functions of WWER-1000 are adequately covered by the safety systems. 4 refs., 2 tabs.

Final report on research project: Soil liquefaction testing and evaluation for Kozloduy nuclear power plant units 5 and 6

Energy Technology Data Exchange (ETDEWEB)

Simeonov, S [Energoproekt plc., Power Consulting Engineers, Hydropower Division, Sofia (Bulgaria)

1995-07-01

The object of this study is the region of the channels of additional technical water supply of Kozloduy NPP, Units 5 and 6. This region is chosen because there are enough data for water saturated sands, necessary for the analysis, including data from cyclic triaxial tests and standard penetration tests. Three kinds ofprocedures for estimation of liquefaction potential of water saturated sands are used in the study. The results obtained by different procedures were compared, analyzed and conclusions drawn about the liquefaction potential of water saturated sands in the area of the channels of additional technical water supply.

Auto-radiographical study of activity distribution of high-dispersity hot particles from NPP

International Nuclear Information System (INIS)

Bonchev, Ts.; Andreev, Ts.; Todorov, N.; Andreev, P.; Kasabov, I.

1995-01-01

Autoradiograms of hot particles (HP) detected at Kozloduy NPP have been obtained with ordinary photographic film using direct contact. HP diameter and activity have been calculated by computer processing of the image.The distribution of HP weight and the precipitation time on surfaces has been estimated. Results on 37 HP found at the Kozloduy NPP units 1-4 and 9 HP found in special rooms containing waste are reported. The emitters are identified as 60 Co, 54 Mn and α emitters with specific activities 2.10 8 Bq/g, 2.10 7 Bq/g and 3.10 4 Bq/g respectively. 5 refs., 6 figs., 3 tabs

Safety systems I/C equipment reliability analyses of the Kozloduy NPP units 3 and 4

Energy Technology Data Exchange (ETDEWEB)

Halev, G; Christov, N [Risk Engineering Ltd., Sofia (Bulgaria)

1996-12-31

The purpose of the analysis is to assess the safety systems I/C equipment reliability. The assessment includes: quantification of the safety systems unavailability due to component failures; definition of the minimal cut sets leading to the analysed safety systems failure; quantification of the I/C equipment importance measures of the dominant contribution components. The safety systems I/C equipment reliability has been analysed using PSAPACK (a code for probabilistic safety assessment). Fault trees for the following safety systems of the Kozloduy-3 and Kozloduy-4 reactors have been constructed: neutron flow control equipment, reactor protection system, main coolant pumps, pressurizer safety valves `Sempell`, steam dump systems, spray system, low pressure injection system, emergency feeding water system, essential service water system. THree separate reports have been issued containing the performed analyses and results. 1 ref.

Auto-radiographical study of activity distribution of high-dispersity hot particles from NPP

Energy Technology Data Exchange (ETDEWEB)

Bonchev, Ts [Sofia Univ. (Bulgaria). Fizicheski Fakultet; Angelov, V [Civil Defence Administration, Sofia (Bulgaria); Andreev, Ts; Todorov, N [Kombinat Atomna Energetika, Kozloduj (Bulgaria); Andreev, P; Kasabov, I [Sofia Univ. (Bulgaria). Fizicheski Fakultet

1996-12-31

Autoradiograms of hot particles (HP) detected at Kozloduy NPP have been obtained with ordinary photographic film using direct contact. HP diameter and activity have been calculated by computer processing of the image.The distribution of HP weight and the precipitation time on surfaces has been estimated. Results on 37 HP found at the Kozloduy NPP units 1-4 and 9 HP found in special rooms containing waste are reported. The emitters are identified as {sup 60} Co, {sup 54} Mn and {alpha} emitters with specific activities 2.10{sup 8} Bq/g, 2.10{sup 7} Bq/g and 3.10{sup 4} Bq/g respectively. 5 refs., 6 figs., 3 tabs.

A brief account of Kozloduy 6 full-scope replica control room simulator upgrade experience: An engineering point of view

International Nuclear Information System (INIS)

Dinkov, Y.D.

2006-01-01

A short excursion throughout Kozloduy NPP history, and Kozloduy 6 Full-Scope Replica Control Room Simulator procurement, is proposed for a reader, which is not familiar with the Kozloduy circumstances. A brief account of five year operation and upgrade experience is presented as seen by the Kozloduy simulator engineering team. During the last five years Kozloduy 6 is going through a complex and expensive modernization programme so Simulator is a subject of a series of changes twice per year. Simulator is used for training six months of the year during spring and autumn most of this time in two shifts daily. Remaining six months during winter and summer are allocated to other simulator uses including five months downtime for hardware reconstruction, software integration, troubleshooting and testing. Quantitative information concerning scope of software and hardware changes is given. Kozloduy NPP simulator engineering team approach toward various upgrade projects is given in an attempt to facilitate a discussion about how a simulator upgrade should be performed. Projects mentioned vary from small to big, in-house or contracted, already completed or planned for future realization

The Kozloduy absurdity: Legal and political dimensions of the Bulgarian Nuclear Power Plant issue

International Nuclear Information System (INIS)

Semov, A.

2006-01-01

The issue of Kozloduy NPP is long-standing and sensitive. Complicated technical, legal, economical, political and purely ethical issues are involved in it. Their entire review in this brief presentation is impossible. The paper therefore only dwells on some of the major issues, the way they have been presented by the Civil Committee for Kozloduy NPP Defence. Following an outline of the way the situation developed, the paper discusses legally binding acts and then considers other legally relevant factors. The possible existence of a friendly political climate in Europe allowing reconsideration of the matter is also dealt with. (author)

Design safety improvements of Kozloduy NPP to meet the modern safety requirements towards the old generation PWR

International Nuclear Information System (INIS)

Hinovski, M.P.; Sabinov, S.

2001-01-01

Activities related to safety improvement of Kozloduy NPP units, started at the end of 1970s included seismic resistance upgrading, fire safety improvement, reliable heat final absorber etc. During the last 10 years the approach was systematized and improved. Units 1 to 4 are of great interest; therefore here we will discuss these units only. As a result of studies and analyses performed at the end of the 1980s and the beginning of the 1990s, problems related to the safety were identified and complex of technical measures was developed and planned. A considerable part of these measures has already been implemented, and the rest will be performed during the next years. Activities were performed by stages, and at the moment the last stage is under way. It shall be finished by the year 2003. The number of the measures is quite large to describe them here in full scope -- during the first stage of the safety program (1991-1993) were developed and analyzed more than 4200 documents and more than 160 measures were executed. During the second and third stages more than 300 important improvements were realized. In the frame of the program, financed by EBRD, 10 new systems with great importance were implemented and 8 systems were significantly modified. The main measures are described below. (author)

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

International Nuclear Information System (INIS)

Sechensky, B.

2005-01-01

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

Medical consequences of NPP and TPP operation

International Nuclear Information System (INIS)

Bliznakov, V.

1996-01-01

Results from a comparative analysis of health conditions of the staff in the Kozloduy NPP and the Maritsa Iztok TPP are reported. It is found that the general disease incidence with temporary incapacity for work of Kozloduy workers is lower than those data for the workers at thermal power stations. The incidence of some social diseases like neoplasms, TBC, hypertension, ischemia etc. is also lower for the staff of NPP. No cases of radiation injuries have been registered for a period of 21 years

Calculational results for radiation embrittlement of WWER pressure vessel at the Kozloduy NPP

Energy Technology Data Exchange (ETDEWEB)

Apostolov, T; Ilieva, K; Petrova, T [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. za Yadrena Izsledvaniya i Yadrena Energetika

1996-12-31

Determination of radiation impact on metal state in the case of WWER-440/230 is made only by calculation methods since a special sample-witness (SW) incorporation had not been implemented. In WWER-1000 reactors such SW are foreseen but their spots are high above the active core. This is why in both reactors the appliance of a calculational procedure for radiation embrittlement determination is compulsory. The authors propose such a procedure accounting for the change in critical temperature of neutron brittleness by the neutron fluence. The neutron fluence and the shift of critical embrittlement temperature have been calculated for the maximum overloaded location and for the weld metal of the Kozloduy-5 and Kozloduy-6 reactors (WWER-1000). The shift of critical temperature in weld 4 of the Units 1-4 (WWER-440) is plotted versus work cycles and compared to experimental values. 4 figs., 5 tabs.

Regulatory aspects of NPP safety

International Nuclear Information System (INIS)

Kastchiev, G.

1999-01-01

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

Seismic upgrading of the spent fuel storage building at Kozloduy NPP

International Nuclear Information System (INIS)

Alexandrov, A.; Borov, V.; Jordanov, M.; Karamanski, T.; Mihaylov, K.

2001-01-01

The Spent Fuel Storage Building at Kozloduy NPP site has been analysed for new review level earthquake with 0.2 g peak ground acceleration (compared to the initial design basis earthquake with 0.1 g PGA). The preliminary seismic analysis of the existing building structure using the 5% site specific response spectrum showed the need of seismic structural upgrading. Two upgrading concepts were evaluated on the basis of several factors. The main factor considered was preventing the collapse of the hall structure and the travelling cranes on the fuel storage area during and after a SSE. A three dimensional finite element model was created for the investigation of the seismic response of the existing structure and for the design of the building upgrading. The modelling of the heavy travelling crane and its sub-crane structure was one of the key points. Different configurations of the new upgrading and strengthening structures were investigated. Some interesting conclusions have been drawn from the experience in analysing and upgrading of such a complex industrial structure, comprised of elements with substantial differences in material, rigidity, construction and general behaviour. (author)

Safety systems I/C reliability analysis of the Kozloduy NPP units 5 and 6; Analiz nadezhnosti KIP i sistem bezopasnosti pyatogo i shestogo bloka AEhS `Kozloduy`

Energy Technology Data Exchange (ETDEWEB)

Marinova, B [Risk Engineering Ltd., Sofia (Bulgaria)

1996-12-31

The purpose of the analysis is to assess the safety systems I/C equipment reliability of the Kozloduy-5 and the Kozloduy-6 reactors. The assessment of quantitative and qualitative effect of control systems unavailability on the safety systems unavailability is performed. The analysis is limited to the following systems: sprinkler management, low pressure emergency spray, emergency injection of boric acid, hydro accumulators, pressure compensator and compressed air. The code for probabilistic safety assessment PSAPACK has been used in analysis. Fault trees for all analysed safety systems have been constructed. Results indicates a high reliability of the safety systems management.

Design and implementation experience of seismic upgrades at Kozloduy and Paks NPPs

Energy Technology Data Exchange (ETDEWEB)

Borov, V; Trichkov, V; Alexandrov, A; Jordanov, M [EQE-Bulgaria, Sofia (Bulgaria)

1995-07-01

Series of upgrades have been designed and implemented by EQE-Bulgaria at Kozloduy NPP and as a subcontractor of EQE-International - at Paks NPP. Wide variety of facilities have been upgraded, including Electrical Equipment, Control and Instrumentation Equipment, Technological Equipment, Brick Walls and Building Structures. Different design approaches and concepts have been applied in compliance with the specific technological and structural conditions. The effect of the excitation intensity as well as the presence of specific floor response spectra over the upgrading concept and cost is discussed. Specific problems of supporting heavy technological equipment are noted. A practical approach for seismic upgrading of Brick Walls, as well as a tendency for unification of the engineering design is shown. The first completely upgraded Building Structure at Kozloduy NPP is the structure of the Electrical Control Building to the Diesel Generator of the River-bank Pump Station. Specific problems of the implementation of the final upgrading design of the Diesel Generator Building are outlined. (author)

Design and implementation experience of seismic upgrades at Kozloduy and Paks NPPs

International Nuclear Information System (INIS)

Borov, V.; Trichkov, V.; Alexandrov, A.; Jordanov, M.

1995-01-01

Series of upgrades have been designed and implemented by EQE-Bulgaria at Kozloduy NPP and as a subcontractor of EQE-International - at Paks NPP. Wide variety of facilities have been upgraded, including Electrical Equipment, Control and Instrumentation Equipment, Technological Equipment, Brick Walls and Building Structures. Different design approaches and concepts have been applied in compliance with the specific technological and structural conditions. The effect of the excitation intensity as well as the presence of specific floor response spectra over the upgrading concept and cost is discussed. Specific problems of supporting heavy technological equipment are noted. A practical approach for seismic upgrading of Brick Walls, as well as a tendency for unification of the engineering design is shown. The first completely upgraded Building Structure at Kozloduy NPP is the structure of the Electrical Control Building to the Diesel Generator of the River-bank Pump Station. Specific problems of the implementation of the final upgrading design of the Diesel Generator Building are outlined. (author)

Knowledge management at Kozloduy NPP - challenges and solutions

International Nuclear Information System (INIS)

Tzotchev, S.; Pironkov, L.

2004-01-01

Like any highly technical endeavor, the use of nuclear technology relies heavily on a vast accumulation of knowledge - volume upon volume of scientific research, engineering analysis, design documentation, operational data, maintenance records, regulatory reviews and countless other pieces of technical information, combined with complex reservoir of scientists, engineers, technicians and managers with relevant background and expertise. The effective management of nuclear knowledge includes systematic and organized application of accumulated specific knowledge as well as ensuring the sustainable availability of qualified personnel. This means that: 1) The know-how should be properly identified, captured and classified; 2) Adequate tools for support, access and transfer of data should be available; 3) Renewing of workforce without loss of institutional memory should be guaranteed. During the centuries this process has been applied spontaneously and there are a lot of examples that the world use to be workable earlier too. However nowadays this type of spontaneous knowledge management is ineffective. Information volume and the communication efficiency have increased so much that new tools have to be created to handle the knowledge being communicated trough numerous sources. Besides information space is strongly polluted. The information channels provide unnecessary redundant information. Target oriented searching and delivering of useful information is difficult and requires significant resources. What value this know-how represent, how can it be maintained for and passed to the next generation, what are the problems of aging and renewing of workforce, what measures have been taken by Kozloduy NPP and what are the challenges to be faced yet - these are the issues to be addressed in this paper. (authors)

Estimation of the influence of the early termination of the operation of units 1- 4 in NPP Kozloduy on the greenhouse gas emissions and the obligations of Republic of Bulgaria regarding the Kyoto Protocol

International Nuclear Information System (INIS)

Christov, Chr.; Vasilev, Hr.

2003-01-01

The case of early termination of the operation of units 1 - 4 in NPP 'Kozloduy' would have a considerable impact on the greenhouse gas (GHG) emissions because in the structure of the electricity production the nuclear power plant occupies over 40%. Due to decrease of the share of the nuclear energy in the electricity production the share of the solid and gaseous fuels increases. They are a considerable source of GHG. Three scenarios for the development of the electric power sector until year 2015 have been studied for the case of early termination of the operation of units 1 - 4 in NPP: Scenario 1: Early termination of the operation of units 1 - 4 according to terms pointed out by the EU. Scenario 2: Decommissioning of units 1 - 4 according to term in the project design. Scenario 3: Early termination of the operation of units 1 - 2 according to terms pointed out by the EU and decommissioning of units 3 - 4 according to terms in the project design. Comparative calculations have been performed for the forecasted GHG emission quantities in the first commitment period of the Kyoto Protocol (2008 - 2012). The potential for possible quantities of GHG emissions that could be traded during the entire five-year period are estimated. At minimum possible price of the emissions 5 $US/tCO 2 the annual income will be at least 100 - 130 mill $US. The realistic estimation regarding the omitted benefits due to early termination of the operation of units 1 - 4 is about 900 mill $US for the five year period of Kyoto. The continued operation of units 3 - 4 to the end of the term defined in the project design could make it possible to fulfill an income of 700 mill to 1 billion $US from emission trading

Initial data of seismic input and soil conditions of Kozloduy NPP site. Extension to Part 2 soil conditions, issued October '93

International Nuclear Information System (INIS)

Boyadjiev, Z.

1995-01-01

On the basis of the results of the carried out experimental (laboratory and in situ) investigations of the dynamic characteristics, the following conclusions for the Kozloduy NPP site are presented. (1) The established through experimental studies relationships for the shear module and the damping factor as strain dependent of representative samples of soils of the site profile, can be used for all similar soils in the profile in the different parts of the site, taking into account the possible differences by means of the initial shear module in the normalized relationship for the respective generalized soil type. (2) When solving the problems of the site response and the 'soil - structure analysis', the geotechnical seismic model of the 'free field' profile can be assumed for all parts of the NPP site. (3) The changes of the lithological profile in different parts of the site, in respect to type and thickness, as well as in view of the different way and depth of the NPP structures foundation, make it necessary the elaboration of a geotechnical seismic model of the profile below the foundation plates of the reactor buildings of the NPP units in each particular case. These models can be made out on the basis of the summarized data about the shear velocities of the soil types, the lithological data of the studied boreholes in these places and the data having natural bulk density from 30 - 40 m depth determined by the laboratory studies of samples of these soils, assuming with approximation that the geotechnical seismic model below this depth is the same as the one of the 'free field'. (4) Studies have been carried out through in situ and laboratory studies of all the fundamental structures on the NPP site and the results of them are sufficient as an addition to the present initial data for solving the problems of the site response and the 'soil-structure inter-action' analyses of each structure

The development of the Kozloduy NPP in the conditions of liberalized energy market

International Nuclear Information System (INIS)

Ivanov, A.

2003-01-01

production show that the following processes are significant: social pressure for limitation og the nuclear power and programs for waste storage; extension of the term for the building of new nuclear facilities; increase of the funds for new facilities and maintenance of the existing ones. The conception, developed for the Kozloduy NPP in the competitive environment includes: limitation of the government role in the management and commercial activities; organization of a electricity producers pool (from different type of electricity production) with share in the electricity distribution. In the same pool with the Kozloduy NPP other capacities supplying up to 30% reserve should be present. For granting of a long-term development of the formation and providing of a minimal reliable market, consumers should be integrated

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)

Stinshoff, Helmut; Weber, Patrick

2006-01-01

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)

Inspection Qualification Centre in NPP 'Kozloduy'

International Nuclear Information System (INIS)

Mikhovski, M.

2000-01-01

In May 1999 according to the working plan of the IAEA project RER 4/020 and the decision of the NPP the Inspection Qualification Centre (IQC) has been established in order to provide examination services in the NPP. During year 1999 IVC (AEA Technology) in the framework of the DTI project provides consulting and technical assistance to the NPP, IQC, Bulgarian Academy of Sciences and Regulatory Authorities in setting up the IQC infrastructure. Now IQC work as an independent inspection body B type. The IQC activities for the period 1999-2000 are presented and further tasks are outlined

Spent fuel generated by the Kozloduy nuclear power plant within the period 1974 - 1994

International Nuclear Information System (INIS)

Peev, P.

1994-01-01

The spent fuel management during the 20-year operation of Kozloduy NPP is described. Formally this period is divided into two stages. The first one covers 1977 - 1988 when the spent fuel after short-term (3 years) storage in the reactor building was dispatched to the former Soviet Union. Within this period 21 shipments of spent fuel (about 3086 fuel assemblies) with various level of enrichment and burnup were performed. The second stage covers the period 1988 - 1994. In that period the authorities responsible for the safe operation of Kozloduy NPP faced a number of problems related to necessity of on-site spent-fuel storage commissioning. A reassessment of the seismic risk after Vrancha earthquake and the Russia's attitude towards the former Soviet Union policy of spent fuel storage was discussed

Spent fuel generated by the Kozloduy nuclear power plant within the period 1974 - 1994

Energy Technology Data Exchange (ETDEWEB)

Peev, P [National Electricity Company, Sofia (Bulgaria)

1994-12-31

The spent fuel management during the 20-year operation of Kozloduy NPP is described. Formally this period is divided into two stages. The first one covers 1977 - 1988 when the spent fuel after short-term (3 years) storage in the reactor building was dispatched to the former Soviet Union. Within this period 21 shipments of spent fuel (about 3086 fuel assemblies) with various level of enrichment and burnup were performed. The second stage covers the period 1988 - 1994. In that period the authorities responsible for the safe operation of Kozloduy NPP faced a number of problems related to necessity of on-site spent-fuel storage commissioning. A reassessment of the seismic risk after Vrancha earthquake and the Russia`s attitude towards the former Soviet Union policy of spent fuel storage was discussed.

Qualitative and quantitative methods for human factor analysis and assessment in NPP. Investigations and results

International Nuclear Information System (INIS)

Hristova, R.; Kalchev, B.; Atanasov, D.

2005-01-01

A description of the most frequently used approaches for human reliability assesment is given. The relation between different human factor causes for human induced events in Kozloduy NPP during the period 2000 - 2003 is discussed. A comparison between the contribution of the casual factors for events occurrences in Kozloduy NPP and an Japanese NPP is presented. It can be concluded that for both NPPs the most important casual factors are: 1) written procedures and documents; 2) man-machine interface; 3) environmental working conditions; 4) working practice; 5) training and qualification; 6) supervising methods

A cytogenetic study of personnel of the Kozloduy NPP with a view to the hazards of late effects

Energy Technology Data Exchange (ETDEWEB)

Bulanova, M; Benova, D; Georgieva, I; Georgieva, V; Yagova, A; Rupova, I; Kusheva, R; Khadzhidekova, V; Topalova, S; Nikolova, T [National Centre of Radiobiology and Radiation Protection, Sofia (Bulgaria)

1996-12-31

Chromosomal analysis of 40 Kozloduy NPP workers has been carried out. Three cytogenetic end-points have been considered: chromosomal aberrations (CA), sister-chromatid exchanges and micro nuclear assays in peripheral blood lymphocytes. A higher incidence of CA has been detected in the investigated group in comparison with a control group. This is attributed to the radiation factor taking into consideration that the highest occurrence is that of dicentric chromosomes induced by radiation exposure. 95% of the workers have been employed for more than 5 years and 60% have received a dose of more than 30 cSv. However no direct relation of CA incidence to the accumulated dose has been observed. Tobacco smoking potentiates additionally the damage of the chromosome structures caused by ionizing radiation. 15 refs., 3 tabs.

Safety of NPP with WWER-440 and WWER-1000 reactors

Energy Technology Data Exchange (ETDEWEB)

Balabanov, E [Energoproekt, Sofia (Bulgaria); Gledachev, J; Angelov, D [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1996-12-31

The WWER-440 and WWER-1000 reactors used at the Kozloduy NPP have been analyzed in terms of safety. There are currently 4 reactors WWER-440/230 and 2 reactors WWER-1000/320. The former do not comply completely with the modern safety requirements due to the regulations acted in the sixties when they have been designed. The main features of these reactors are: low power density in the core; three levels of reactor control and protection; six primary loops; horizontal steam generators; two turbines; large number of cross-unit connections. The low thermal density in the core, the low specific thermal loading in the rods and the large coolant inventory enhance the safety, while the major deficiencies are identified as follows: insufficient capabilities for emergency core cooling; low diversification and physical separation of the safety systems; old fashioned control systems; inadequate fire protection; lack of full containment. It is pointed out that several design and operation actions have been completed in the Kozloduy NPP in order to enhance their safety. The WWER-1000 units are 320 model and feature a high safety level, complying completely with OPB-82 regulations and with all current international safety standards. 3 refs., 7 figs., 1 tab.

Safety of NPP with WWER-440 and WWER-1000 reactors

International Nuclear Information System (INIS)

Balabanov, E.; Gledachev, J.; Angelov, D.

1995-01-01

The WWER-440 and WWER-1000 reactors used at the Kozloduy NPP have been analyzed in terms of safety. There are currently 4 reactors WWER-440/230 and 2 reactors WWER-1000/320. The former do not comply completely with the modern safety requirements due to the regulations acted in the sixties when they have been designed. The main features of these reactors are: low power density in the core; three levels of reactor control and protection; six primary loops; horizontal steam generators; two turbines; large number of cross-unit connections. The low thermal density in the core, the low specific thermal loading in the rods and the large coolant inventory enhance the safety, while the major deficiencies are identified as follows: insufficient capabilities for emergency core cooling; low diversification and physical separation of the safety systems; old fashioned control systems; inadequate fire protection; lack of full containment. It is pointed out that several design and operation actions have been completed in the Kozloduy NPP in order to enhance their safety. The WWER-1000 units are 320 model and feature a high safety level, complying completely with OPB-82 regulations and with all current international safety standards. 3 refs., 7 figs., 1 tab

Operational behaviour of WWER nuclear power units after Chernobyl accident

International Nuclear Information System (INIS)

Milivojevic, S.; Spasojevic, D.

2000-01-01

The indicators of effectiveness of WWER operation, in 1987-1998 were analyzed. For three groups of nuclear units (WWER, NPP Kozloduy, NPP Paks), the trends of Indicators flow were established. The comparative analysis of forced outage rate, and load factor of WWERs and nuclear units all in the world was carried out; it gives the general picture of accident influence on the states and the relations of these indicators in considered period (author)

Calculational experimental examination and ensuring of equipment and pipelines seismic resistance at starting and operating water-cooled and moderated reactor WWER-type NPPs. Final report

International Nuclear Information System (INIS)

1999-01-01

The results of testing of equipment at Bohunice NPP and pipeline systems at Unit 3 of Kozloduy NPP (WWER-440 type reactors) are presented in this Final Report. These results side by side with experimental values of natural frequencies and decrements also include experimental data about vibration modes of tested equipment and pipelines. For the first time the results of new calculational-experimental examination of equipment seismic resistance at Unit 2 of Armenian NPP are presented. At Kozloduy NPP direction's request the planed additional tests of some selected items were put off on 1997. Instead of postponed tests we carried out detailed analysis of our past inspections of numerous equipment seismic resistance at the Unit 5 of Kozloduy NPP. Experimental data with results of additional analysis are presented

Detection of primary coolant leaks in NPP

International Nuclear Information System (INIS)

Slavov, S.; Bakalov, I.; Vassilev, H.

2001-01-01

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 40 0 - 60 0 C 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

Nuclear safety improvement activities related to WWER-440 units in Bulgaria

International Nuclear Information System (INIS)

Gantchev, T.

1998-01-01

The systematic evaluation of the deficiencies of the original design of the WWER reactors brought to the development of a Short Term Programme for Safety Upgrading and Modernisation of Kozloduy WWER-440 units. The implementation of this Programme was completed in 1997. The strive for continuos improvement of Kozloduy Nuclear Power Plant (NPP) safety level, the new requirements of the Bulgarian Nuclear Safety Authority and the public concern initiated the development of new Complex Programme for Safety Improvement (PRG'97), now in a process of implementation. (author)

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 4E. Paks NPP: Analysis and testing. Working material

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-01

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

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 4E. Paks NPP: Analysis and testing. Working material

International Nuclear Information System (INIS)

1995-01-01

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

The World Bank mission in Bulgaria with the objective of estimating the possibility to increase the safety of the Kozloduy NPP

International Nuclear Information System (INIS)

Laaksonen, J.

1992-01-01

This is a report of the World Bank mission in Bulgaria held from 22 March to 31 April 1992. The author considers the present state of the safety level of all Kozloduy NPP reactors with emphasis of the units 1-4 which are of the WWER-440/230 type. Three main factors are discussed in detail: 1) design inherent safety; 2) equipment protection from accidental events connected with the equipment quality; 3) quality and culture of operation and quantitative evaluation of the safety. The areas requiring special attention in view of the safety enhancing are: safety goal policy; creation of national safety culture; planning and implementation of the improvement programme; assuring the equipment reliability; updating and protection the existing systems; furnishing the plant with new systems. A review of all on-going and proposed projects of the national authorities, IAEA, EC, WANO and BEQE is made. Some remarks are given also about the WWER-1000 type units 5 and 6. The estimated cost of all necessary measures for equipment improvement is $100-200 million and of the annual investment after the main reconstruction and innovation of the reactors - about $10 million which should be included in the normal operational expenses of the plant. A new approach to the responsibility role of the Bulgarian specialists should be created. A new and well grounded proposal for modifications in the equipment should be made from the National Electrical Company including economical evaluations. Another expert assessment will be requested from the foreign banks before financing

Revision report about the in-situ tests of 1000 MW unit 5 Kozloduy (Bulgaria)

International Nuclear Information System (INIS)

Muzzi, F.

1995-01-01

This report refers to the technical revision performed on the technical report about the in-situ tests performed on 1000 Unit 5 nuclear power station of Kozloduy (Bulgaria), within the frame of the IAEA benchmark study for the seismic analysis and testing of an existing Nuclear Power Plant. After a foreword to define the aims of the job and the identification of the scope of the work, a brief description of the plant is made. A brief description of the theory about the modal parameter determination and the soil-structure interaction analysis by experimental tests is made. The following chapters collect some comments about the tests carried out in Kozloduy, with special reference to the general correctness of testing procedure and to data special requirements for the seismic safety margin assessment procedures to be applied on the existing power station

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 4F. Paks NPP: Analysis and testing. Working material

International Nuclear Information System (INIS)

1999-01-01

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

Report of the experts' mission to review thermal hydraulic and structural analyses for PTS assessment of Kozloduy NPP units 1-4 reactor pressure vessels, Sofia, Bulgaria 3-7 April 1995

International Nuclear Information System (INIS)

1995-01-01

Based upon a request of the Government of Bulgaria and in order to assist its Regulatory Body, an experts' mission was carried out to Sofia and Kozloduy, 21-25 November 1994 within the framework of the IAEA TC Project BUL/9/013-05 and of the IAEA Extrabudgetary Programme on the Safety of the WWER NPPs. The mission also specified the technical content of further assistance by the IAEA. With respect to the findings and recommendations made in November 1994, WWER-SC-109, a follow-up expert's mission was carried out to Sofia, Bulgaria, April 3-7, 1995. The objective of the mission was to review the selection of transients, thermal hydraulic, stress and fracture mechanics analyses for reactor pressure vessel integrity assessment of Kozloduy unit 1-4. In addition, an update on the activities completed, underway and planned related to unit 1 reactor pressure vessel embrittlement was presented and discussed. The review was carried out by 4 international experts from Finland, France, Russia and IAEA in co-operation with the Bulgarian regulatory body, plant, Energoproject Sofia and Institute of Metals staff. The mission was conducted out within the frame of the IAEA TC Project BUL/9/013-05 and of the IAEA Extrabudgetary Programme on the Safety of the WWER NPPs. 18 refs

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 4G. Paks NPP: Analysis and testing. Working material

International Nuclear Information System (INIS)

1999-01-01

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

Equipment maintenance as a tool for raising of safety and efficiency of the NPP'Kozloduy' operation

International Nuclear Information System (INIS)

Kichev, E.

1999-01-01

The role of the maintenance in the NPP management is discussed. The main links in the management are: NPP executives and their position; maintenance; quantitative characteristics of the maintenance. The described management process gives the opportunity the maintenance optimization on different levels: component, system, unit, plant. The results are valid for other areas with high safety requirements

Plant life extension and ageing mechanisms: an ANSALDO proposal for the application to Kozloduy NPPs

International Nuclear Information System (INIS)

Orlandi, S.; Macco, A.; Zanaboni, P.

1999-01-01

In the frame of extension of NPP's installations lifetime, ageing management has become a topical subject to obtain the items: - Evaluation of residual life of the plant through the investigation of the residual life of well identified Safety Related Equipment in the as built configuration; - Organization of identified representative equipment per typological Classes (as Piping Systems, Tanks, Valves, Pumps, Electrical Equipment, Pressurized Components) in order to define for each High Level Class a set of elementary families capable to have, within each family, a common ageing mechanism and methodological investigation and potential common on-line monitoring; Application of a consistent methodology for residual life evaluation at each High Level Class (and subsequent elementary family and group if any) in order to assess an integral approach to backfitting and ageing management, taking also into account the economical investment effort required to the utility. In this report, a technical proposal for the application of the ANSALDO standard methodology approach, applied to the re-evaluation of the Kozloduy NPP's (Unit 1 - to 4) is presented. (authors)

Unit Commissioning of “Belene” NPP (Bulgaria)

International Nuclear Information System (INIS)

2009-01-01

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

Improving nuclear safety of VVER-440 units

International Nuclear Information System (INIS)

Nochev, T.; Sabinov, S.

2001-01-01

In this paper authors deals with improvement of nuclear safety of WWER-440 units in Kozloduy NPP. Main directions for improving nuclear safety of WWER-440 units were: - to expand number of the design accident; - to increase reliability of equipment important for the safety; - to decrease the probability of initiating events; - improvements the integrity of the primary circuit (application LBB concept, qualification of the pressure safety valves to avoid pressurized thermal shock); - improvement of the fire protection; - improvement of the operation including upgrading and improvement of operational documents, implementation of new system for training the operators and etc.; - reassessment of the seismic response of the plant. Main actions were made at NPP Kozloduy to increase nuclear safety of VVER-440 units. 1. Modernization of Emergency High Pressure Safety Injection System. The modernization includes dividing of independent channels with reservation of active elements. Pumps were exchanged with more effective and reliable ones. HPSIS was increased reliability in general through decrease number of active elements and exchanged with passive. 2. For the purpose of avoiding fast cooling at the primary circuit and obtaining thermal shock of reactor vessel, Main Safety Insulation Valves are installed at NPP Kozloduy. 3. Modernization of Emergency power supplies AC. Oil breakers VMP-10 are exchanged with gas FS-4. 4. Generator breakers are installed to decrease probability of loss power supply and blackout. They provide reliable power supply to the system important for the safety in case of failure on generator. 5. I and C system has been qualified and optimized. 6. Reassessments of Limiting Conditions of Operation and new scram signals have been introduced. 7. An operators-oriented Informational System has been developed. It includes ensuring and updating of equipment data, new informational support of operator and etc. 8. A new auxiliary independent system for

Health risk indicators in NPP - a continuous discussion

International Nuclear Information System (INIS)

Bliznakov, V.

1999-01-01

An evaluation of the costs connected with the health consequences due to occupational exposure for the personnel in the NPP 'Kozloduy' is made. The methods used are WTP (willingness to pay) and COI (cost of illness). The estimations in USD are as follows: for chronic bronchitis in adults 126 000 - 3336 000 (WTP); visit to medical unit - 265 - 795 (COI); asthma attacks per day - 12 - 55 (WTP); acute respiratory syndrome - 5 - 15 (WTP). Health - demographic data are used for the risk assesment. The weighted mean value for personnel irradiation is 2.5 - 8.7 mSv/year. Determination of individual dose limit, individual radiation risk, and individual annual dose limit is discussed

Report of an experts' mission to review the modernization programme of the Kozloduy NPP units 5 and 6 Kozloduy, Bulgaria 26 June - 1 July 1995

International Nuclear Information System (INIS)

1995-01-01

The purpose of the IAEA Safety Review Mission was to review the safety aspects of the Kozloduy 5/6 modernization programme, and to advise on the completeness and adequacy of the safety improvements proposed. The IAEA draft report ''Ranking of Safety Issues for WWER-1000 Model 320 NPPs'', WWER-SC-104, 1995-05-29 (referred to as the Issue Book in the subsequent text) was the basis for the experts' review. The IAEA NUSS standards and guides, and internationally accepted safety concepts and practices and national standards, complemented by the Russian safety rules in force, were used in the preparation of the issue book. The scope of the review covered the plant design and operational safety aspects as proposed in the modernization programme. The upgrading measures, which are only related to the improvement of plant availability, were not included in the review

Resins characterization strategy at Kozloduy Nuclear Power Plant

International Nuclear Information System (INIS)

Fenoy, A.; González, R.; Molleda, P.; Sánchez, L.; Herrera, J.

2013-01-01

The Consortium ENSA- Gas Natural Fenosa Engineering has a contract with Kozloduy Nuclear Power Plant (KNPP) for the retrieval and conditioning of the resins. Before that, the project deals with resins characterization to verify the fulfillment the Bulgarian authorities’ requirements. The project includes all the resins generated during the operation of the BACKGROUND Resins characterization strategy at Kozloduy Nuclear Power Plant units 1, 2, 3 and 4, which were stored into six big dimensions tanks: four low tanks and two intermediate tanks. They only have a manhole above for tanks access. The methodology and the progress of the work are presented

A study of the pressure vessel steel of the WWER-440 unit 1 of the Kozloduy nuclear power plant

Science.gov (United States)

Kostadinova, E.; Velinov, N.; Avdjieva, T.; Mitov, I.; Rusanov, V.

2017-11-01

A comparison between highly neutron irradiated samples from the region of weld № 4 and low irradiated samples from weld № 1 taken from the pressure vessel of the WWER-440 Unit № 1 of the Kozloduy NPP has been performed. Measurements of the residual activity of samples from the outer surface of the reactor pressure vessel bottom corpus reveal very low activity of 60Co. Insofar as there the base and weld metal appear to be exposed to a very low neutron fluence, the samples from these locations can be considered as practically not affected and may serve as a reference basis for comparison with highly irradiated pressure vessel regions. The Mössbauer parameters isomer shift (IS) and quadrupole splitting (QS) were found to be absolutely irradiation insensitive. A stepwise reduction of the internal hyperfine magnetic field Bhf, each by about 2.6 T, was observed. This can be attributed to the replacement of one or two surrounding iron atoms as first nearest neighbors by non-iron alloying atoms. The Mössbauer experimental line widths for irradiated and non-irradiated samples are practically the same, which is a quite unexpected result. The area fraction ratio for the three main Zeeman sextet subspectra S1:S2:S3 shows very high irradiation sensitivity. For the bottom low irradiated region of the reactor vessel the values are S1:S2:S3 = 50.1:40.0:9.4. After seven years of operation between the pressure vessel annealing in 1989 and the autumn of 1996 when the samples from weld № 4 were taken the ratio changes strongly to S1:S2:S3 = 56.4:34.7:8.5. A possible explanation of this result is that neutron irradiation gives rise to a precipitation process involving predominantly alloying atoms as Ni, Mn, Cr, Mo and V which become mobile and precipitate in the form of carbides and/or P-rich phases and alloying atom aggregates. This "refinement" process lowers the partial area of subspectra S2 and S3 where alloying atoms are involved and leads to a higher area fraction of

Kozloduy NPP units 1-4 significance for Bulgaria

International Nuclear Information System (INIS)

Georgiev, J.

2003-01-01

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

Experiences in seismic upgrading of equipment and structures in Kozloduy nuclear power plant (440 WWER-PWR)

International Nuclear Information System (INIS)

Ordonez Villalobos, A.

1993-01-01

Within the framework of the 'Emergency programme for Nuclear Safety of Kozloduy NPP' it has been concluded that the increase in seismic safety of a NPP can be achieved by upgrading the key equipment in a cost effective way. Essential and vulnerable equipment has to be identified. Seismic capacity should be evaluated base don realistic state of the art criteria. Seismic review teams ef experienced engineers should conduct planned walk-downs in order to propose effective upgrading solutions. Team work of plan engineers and construction engineers would enhance the effectiveness of the solutions. It is recommended that all the participants be motivated and have a clear understanding of the objectives of the upgrading

Determination of P, Cu, Cr, Va and Ti in samples of welded joint No.4 of Kozloduy-1 reactor pressure vessel; Opredelenie soderzhanya fosfora, medi, nikelya, khroma, vanadya i titana v struzhkakh 4 shva 1 bloka AEhS `Kozloduy`

Energy Technology Data Exchange (ETDEWEB)

Taskaev, E [Kombinat Atomna Energetika, Kozloduj (Bulgaria); Penev, I; Taskaeva, M [Bylgarska Akademiya na Naukite, Sofia (Bulgaria). Inst. za Yadrena Izsledvaniya i Yadrena Energetika; Aleksieva, L [Sofia Univ. (Bulgaria); Tsokov, P [Kombinat Atomna Energetika, Kozloduj (Bulgaria)

1996-12-31

An analysis of reactor steel composition has been carried out in 1989 in order to determine metal embrittlement. The samples consist of shavings taken at 3-4 mm depth from the 4-th welded joint of Unit 1 of the Kozloduy NPP. The shavings have been gradually dissolved in a mixture of acids and the solution evaporated. Quantitative analysis has been carried out by spectrophotometry and by ICP emission spectroscopy. The following element concentrations have been found: P - from 0.0462 to 0.052% by weight; Ni - 0.25 - 0.26% (passport data 0.29%); Cr - 1.47 - 1.54 (passport 1.58%); V - 0.1% (passport 0.15%); Cu - 0.11-0.13% (passport 0.12); Ti - 0.002. The data have been used to calculate metal embrittlement. 4 refs., 8 tabs.

Actual status of project Mochovce NPP units 3 and 4 completion

International Nuclear Information System (INIS)

Niznan, S.

2005-01-01

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.

Malignant neoplasm rate in inhabitants of the Kozloduy NPP area; Zabolevaemost` zlokachestvennymi novoobrazovaniyami sredi naselenya v rajone AEhS `Kozloduy`

Energy Technology Data Exchange (ETDEWEB)

Dimitrov, P [National Centre of Radiobiology and Radiation Protection, Sofia (Bulgaria)

1996-12-31

Illness incidence of malignant formations in lungs, mammary gland, thyroid gland, lymph and blood producing tissues is investigated in the 30 km area around Kozloduy and compared to data from two other locations in Bulgaria. The number of malignant growth in the lungs, mammary or thyroid gland on 100 000 persons is lower than the average number for the country as a whole. The number of malignant formations in lymph and blood producing tissues is higher than the average number for the country but the difference is statistically insignificant. Thyroid gland diseases occur with very small frequency for the investigated period (1985-1990). 8 refs., 4 figs.

About choosing the power unit of NPP

International Nuclear Information System (INIS)

Alekseev, P.N.; Mordashev, V.M.; Proshkin, A.A.; Stukalov, V.A.; Subbotin, S.A.; Tsibul'skij, V.F.; Chernilin, Yu.F.

2008-01-01

The present-day domestic nuclear power industry faces the necessity to make both process and economy related decisions. The mentioned decisions should cover all the aspects of the nuclear power complex. In particular, as of now, no substantiation of the present-day and the future requirements for the power unit of the WWER and fast reactor NPPs is available. The choice of the unit power of an NPP should involve consideration of all factors and should not be boiled down to the efforts to ensure the minimization of the investment and the operation constituents of the electric power generation costs. The aim of the present paper was to ensure elaboration of the recommendations to substantiate the optimal unit power of NPP power units based on the analysis of various factors to design, to construct and to operate an NPP (investment, time of construction, the unscheduled shutdown losses, the unification, the fabrication quality, the accident damage, etc.), and the electrical network potentialities and the regional electric power demands [ru

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 1. Data related to sites and plants: Paks NPP, Kozloduy NPP. Working material

International Nuclear Information System (INIS)

1995-01-01

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 sites and NPPs Paks and Kozloduy

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 1. Data related to sites and plants: Paks NPP, Kozloduy NPP. Working material

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-01

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 sites and NPPs Paks and Kozloduy.

To the problem of reliability standardization in computer-aided manufacturing at NPP units

International Nuclear Information System (INIS)

Yastrebenetskij, M.A.; Shvyryaev, Yu.V.; Spektor, L.I.; Nikonenko, I.V.

1989-01-01

The problems of reliability standardization in computer-aided manufacturing of NPP units considering the following approaches: computer-aided manufacturing of NPP units as a part of automated technological complex; computer-aided manufacturing of NPP units as multi-functional system, are analyzed. Selection of the composition of reliability indeces for computer-aided manufacturing of NPP units for each of the approaches considered is substantiated

Quality and Safety Assurance - Priority Task at Nuclear Power Projects Implementation

International Nuclear Information System (INIS)

Nenkova, B.; Manchev, B.; Tomov, E.

2010-01-01

Quality and safety assurance at implementation of nuclear power engineering projects is important and difficult task for realization. Many problems arise during this process, when many companies from different countries participate, with various kinds of activities and services provided. The scope of activities necessary for quality and safety assurance is therefore quite expanded and diverse. In order to increase the safety and reliability of Kozloduy NPP Plc (KNPP) Units 5 and 6, as well as to bring the units in conformity with the newest international requirements for quality and safety in the field of nuclear energy, a program for their modernization on the basis of different technical studies and assessments was implemented. The Units 5 and 6 Modernization Program of Kozloduy Nuclear Power Plant was composed of 212 modifications aimed to improve the safety, operability, and reliability of the Units. The Program was realized by stages during yearly planned outages since year 2002 to 2007, without additional outages. A major Program Objective was to extend the Units Life Time in at least 15 Years, under a continuous, safe, and reliable operation. The Modernization Program of Units 5 and 6 of the Bulgarian Nuclear Power Plant in Kozloduy was the first and for the time being the only one in the world, program in the field of nuclear power engineering, by which the full scope of recommendations for improvement of the Kozloduy NPP units was applied. The main goal of the National Electric Company, which is the Employer for the construction of new nuclear facility in Bulgaria, is after completion of all activities regarding construction of Belene NPP the plant to meet or exceed the requirements of the respective national and international quality and safety codes and standards, as well as the IAEA guidelines, as they are established. The objective of this report is to describe different aspects of the quality assurance according to the requirements of quality and

Project No. 7 - Decommissioning unit at Ignalina NPP. (Engineering and project management)

International Nuclear Information System (INIS)

2000-01-01

In order to manage decommissioning process at Ignalina NPP, a new unit should be established in the framework of the Ignalina NPP organizational structure. The on-site Engineering Project Management Unit (PMU) will adopt an integrated approach to project management , engineering design, planning, procurement, safety and licensing activities at Ignalina NPP site. The PMU will assist the Ignalina NPP management in the development of an integrated decommissioning and waste management strategy

Rest-lifetime evaluation of equipment and facilities of NPP Kozloduy 3 and 4 and development of an ageing management program

International Nuclear Information System (INIS)

Erve, M.; Schmidt, J.; Kastner, B.; Gledatchev, I.; Sabinov, S.; Stoev, M.; Korneev, V.; Strombach, Y.

2001-01-01

The task indicated in the title is part of a comprehensive upgrading program for Units 3 and 4 of the Kozloduy plant executed in a Consortium between Framatome ANP (a Framatome and Siemens company) and the Russian company Atomstroyexport. It comprises an evaluation of the residual service life of components/systems/plants subject to acceptance by international experts, identifying the need for further investigations/calculations in certain cases, and finding solutions for improvements that achieve a consensus of safety and economy. The initial results are: Walkdowns revealed no clear knock-out point for the plants, however there are preliminary hints for necessary further improvements. Investigations of templates taken from the RPV of Unit 1 were started: the results are still preliminary, but can be considered very positive; their transfer to the RPV of Unit 3 would mean that the latest safety analyses of the Unit 3 RPV are conservative. The general work program was successfully applied on the batteries as a pattern for the electrical equipment: parameters for the computer database and proposals for an effective aging management program were addressed. (author)

An approach for Periodic Safety Review (PSR) of units 5 and 6 of Kozloduy NPP

International Nuclear Information System (INIS)

Kichev, Emil

2014-01-01

Periodic Safety Reviews (PSR) is complementary to the routine and special safety reviews and does not replaced them. It determines the level of compliance with current safety requirements and covers all safety aspects of NPP operation and all equipment (SSCs) on site. Three levels of importance are defined for the documents in PSR (towards higher conservatism): Bulgarian documents; IAEA documents; Documents of manufactures and suppliers of the equipment (SSCs). The scope and activities consists of four stages and includes 14 safety factors (SF). Cooperation with external companies and organizations in areas with proved experience is used.

Decommissioning and radioactive waste management. The European Commission overview

International Nuclear Information System (INIS)

Rehak, M

2010-01-01

In this lecture author deals with the European Commission overview on the decommissioning and radioactive waste management. Financial support of European Commission of decommissioning of the Ignalina NPP, Bohunice V1 NPP and Kozloduy Units 1 and 2 is presented.

Recommended reactor coolant water chemistry requirements for WWER-1000 units with 235U higher enriched fuel

International Nuclear Information System (INIS)

Dobrevski, I.; Zaharieva, N.

2011-01-01

The last decade worldwide experience of PWRs and WWERs confirms the trends for the improvement of the nuclear power industry electricity production through the implementation of high burn-up or high fuel duty, which are usually accompanied with the usage of UO 2 fuel with higher content of 235 U - 4.0% - 4.5% (5.0%). It was concluded that the onset of sub-cooled nucleate boiling (SNB) on the fuel cladding surfaces and the initial excess reactivity of the core are the primary and basic factors accompanying the implementation of uranium fuel with higher 235 U content, aiming extended fuel cycles and higher burn-up of the fuel in Pressurized Water Reactors. As main consequences of the presence of these factors the modifications of chemical / electrochemical environments of nuclear fuel cladding- and reactor coolant system- surfaces are evaluated. These conclusions are the reason for: 1) The determination of the choices of the type of fuel cladding materials in respect with their enough corrosion resistance to the specific fuel cladding environment, created by the presence of SNB; 2) The development and implementation of primary circuit water chemistry guidelines ensuring the necessary low corrosion rates of primary circuit materials and limitation of cladding deposition and out-of-core radioactivity buildup; 3) Implementation of additional neutron absorbers which allow enough decrease of the initial concentration of H 3 BO 3 in coolant, so that its neutralization will be possible with the permitted alkalising agent concentrations. In this paper the specific features of WWER-1000 units in Bulgarian Nuclear Power Plant; use of 235 U higher enriched fuel in the WWER-1000 reactors in the Kozloduy NPP; coolant water chemistry and radiochemistry plant data during the power operation period of the Kozloduy NPP Unit 5, 15 th fuel cycle; evaluation of the approaches and results by the conversion of the WWER-1000 Units at the Kozloduy NPP to the uranium fuel with 4.3% 235 U as

Testing of components on the shaking table facilities of AEP and contribution to full scale dynamic testing of Kozloduy NPP. Final report

International Nuclear Information System (INIS)

Ambriashvili, Y.

1996-01-01

This final report summarizes the results of components testing on the shaking table facilities of 'Atomenergoproject' which are considered as a contribution to the full scale dynamic testing of the Kozloduy nuclear power plant Units 5 and 6. It was designed on 1.0 g according to the calculations that were based on accelerograms which included artificial and already known recordings of real earthquakes. Maximum acceleration of the designed spectrum and new spectrum which are recommended are now within the range of frequencies 2.5-20 Hz. Active reactor and the primary loop are seismic stable as well as the tested equipment tested by 'Atomenergoproject'

Development of the temperature field at the WWER-440 core outlet monitoring system and application of the data analyses methods

International Nuclear Information System (INIS)

Spasova, V.; Georgieva, N.; Haralampieva, Tz.

2001-01-01

On-line internal reactor monitoring by 216 thermal couples, located at the reactor core outlet, is carried out during power operation of WWER-440 Units 1 and 2 at Kozloduy NPP. Automatic monitoring of technology process is performed by IB-500MA, which collects and performs initial data processing (discrediting and conversion of analogue signals into digital mode). The paper also presents the results and analyses of power distribution monitoring during the past 21-th and current 22-th fuel cycle at Kozloduy NPP, Unit 1 by using archiving system capacity and related software. The possibility to perform operational assessment and analysis of power distribution in the reactor core in each point of the fuel cycle is checked by comparison of the neutron-physical calculation results with reactor coolant system parameters. Paper shows that the processing and analysis of accumulated significant amount of data in the archive files increases accuracy and reliability of power distribution monitoring in the reactor core in each moment of the fuel cycle of WWER-440 reactors at Kozloduy NPP

RELAP5/MOD3.2 investigation of loss of in-house supply power for WWER 1000/320V

International Nuclear Information System (INIS)

Gencheva, R.; Pavlova, M.; Groudev, P.

2001-01-01

This paper discusses the results of the thermal-hydraulic investigations of the 'Loss of in-house supply power' accident at the Kozloduy NPP Unit 6. The RELAP5/MOD3.2 computer code has been used to stimulate the loss of in-house supply power accident in a WWER 1000 Nuclear Power Plant model. This model was developed at the Institute for Nuclear Research and Nuclear Energy for analyses of operational occurrences, abnormal events and design basis scenarios. It will provide a significant analytical capability for the Bulgarian technical specialists located at the Kozloduy NPP. The criteria used in selecting transient are: importance to safety, availability and suitability of data followed by suitability for RELAP5 code validation. The investigation of 'Loss of normal and reverse AC power' is a process that compares the analytical results obtained by RELAP5/MOD3.2 model of the WWER 1000 against experimental transient data obtained from Kozloduy NPP Unit 6. The comparisons between the RELAP5 results and the test data indicate good agreement

Dry spent fuel storage facility at Kozloduy Nuclear Power Plant

International Nuclear Information System (INIS)

Goehring, R.; Stoev, M.; Davis, N.; Thomas, E.

2004-01-01

The Dry Spent Fuel Storage Facility (DSF) is financed by the Kozloduy International Decommissioning Support Fund (KIDSF) which is managed by European Bank for Reconstruction and Development (EBRD). On behalf of the Employer, the Kozloduy Nuclear Power Plant, a Project Management Unit (KPMU) under lead of British Nuclear Group is managing the contract with a Joint Venture Consortium under lead of RWE NUKEM mbH. The scope of the contract includes design, manufacturing and construction, testing and commissioning of the new storage facility for 2800 VVER-440 spent fuel assemblies at the KNPP site (turn-key contract). The storage technology will be cask storage of CONSTOR type, a steel-concrete-steel container. The licensing process complies with the national Bulgarian regulations and international rules. (authors)

Vibration system identification of Paks and Kozloduy reactor buildings on the basis of the blast test results

International Nuclear Information System (INIS)

Varpasuo, P.

1999-01-01

System identification allows to build mathematical models of a dynamic system based on measured data. System identification is carried out by adjusting parameters within a given model until its output coincides as well as possible with the measured output. The aim of this study is to investigate and model the behavior of complex vibratory systems on the basis of measured excitation and response. The first part of the study describes the theory used in the analysis and the software tools used in the analysis. The second part of the study describes the investigation and modeling of the response of single degree of freedom oscillator excited by sinusoidal and blast excitation. In the third part of the study the system identification of the Kozloduy NPP unit 5 reactor building and Paks NPP unit 1 reactor building is studied and the models are estimated using the method of segmentation of excitation and response. System identification is carried out using MATLAB software by adjusting parameters within a given model until its output coincides as well as possible with the measured output. The types of models used for the were: l) ARX models; 2) ARMAX model; 3) Output-Error (OE) models; 4) Box-Jenkins (BJ) models; 5) State-space models. The model coefficients for different models were calculated using the least-squares and maximum likelihood estimation methods available in MATLAB system identification toolbox. Excitation was in both Paks and Kozloduy case the measured free-field excitation and responses were the vibration responses of the building on the foundation slab level and top of the building. By examining the established models the frequency characteristics of vibration systems were determined with 95 % accuracy and the amplitude response with 80 % accuracy. In case of the steady state response of sinusoidally excited single dof oscillator the modelling gave almost exact results. But in the case of the blast response of the reactor building the obtaining of the

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

International Nuclear Information System (INIS)

Jelev, Adrian

2003-01-01

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)

Decommissioning of units 1 - 4 at Kozloduy nuclear power plant in Bulgaria

International Nuclear Information System (INIS)

Dishkova, Denitsa

2014-01-01

Nuclear safety and security are absolute priorities for the European Union countries and this applies not only to nuclear power plants in operation but also to decommissioning. In terms of my technical background and my working experience in the field of licensing and environmental impact assessment during the decommissioning of Units 1 to 4 at Kozloduy Nuclear Power Plant (KNPP) in Bulgaria, I decided to present the strategy for decommissioning of Units 1 to 4 at KNPP which was selected and followed to achieve safe and effective decommissioning process. The selected strategy in each case must meet the legislative framework, to ensure safe management of spent fuel and radioactive waste, to provide adequate funding and to lead to positive socio-economic impact. The activities during the decommissioning generate large volume of waste. In order to minimize their costs and environmental impact it should be given a serious consideration to the choice, the development and the implementation of the most adequate process for treatment and the most appropriate measurement techniques. The licensing process of the decommissioning activities is extremely important and need to cope with all safety concerns and ensure optimal waste management. (authors)

Bulgaria: INIS Center - 45 years experience

International Nuclear Information System (INIS)

Georgieva, Albena

2015-01-01

Bulgaria is one of 35 countries in the world operating nuclear power plants. Bulgaria's nuclear program was launched in 1956 with the construction of an IRT-2000 research reactor at the Institute for Nuclear Research and Nuclear Energy (INRNE), which was commissioned in 1961. The reactor is now under reconstruction. In 1960, construction of the first Bulgarian nuclear power plant started. At the moment, there are 6 power units at the Kozloduy NPP site; 4 of them (VVER-440/B-230) under decommissioning and 2 (VVER-1000/B-320) in operation. Several storage facilities for radioactive waste, mainly from the Kozloduy NPP and from various sources of ionizing radiation in medicine and industry are also in operation. The Kozloduy NPP, INRNE, Sofia University, the Technical University, and the State Enterprise Radioactive Waste are the main generators of nuclear information in Bulgaria and the main consumers of INIS products. The Bulgarian INIS Center, therefore, maintains continuous and effective cooperation with these Institutions

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

International Nuclear Information System (INIS)

Vasilchenko, I.; Kobelev, S.; Kushmanov, S.

2006-01-01

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

Project management. A discipline which contributes to project success

International Nuclear Information System (INIS)

Hoch, G.

2008-01-01

The presentation covers the following topics: description of the Project - a contract was signed between KNPP and European Consortium Kozloduy (ECK) consisting of Framatome ANP GmbH as Leader (63%), Framatome ANP S.A.S. (17%), Atomenergoexport (20%) ; Project management in the modernization of NPP Kozloduy units 5 and 6; Project management process within AREVA NP GmbH; current status

Investigation of the templets cut out of the Kozloduy Unit 2 reactor pressure vessel

Energy Technology Data Exchange (ETDEWEB)

Klausnitzer, E; Leitz, C; Rieg, C Y [Electricite de France (EDF), 75 - Paris (France); Kryukov, A [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)

1994-12-31

Instrumented impact tests were carried out on sub-size specimens of base and weld metal. Using correlation dependencies, values of ductile-to-brittle transition temperature were determined before and after annealing for base and weld metal corresponding to standard specimen tests. The experimental results were compared to a prediction of the extent of radiation-induced embrittlement of Kozloduy Unit 2 pressure vessel materials. It was confirmed that radiation-induced embrittlement of the base metal does not impose any limitation on the radiation-limited lifetime of the pressure vessel. The predicted increase of the ductile-to-brittle transition temperature of weld metal as a result of irradiation (about 165 C) is practically equal to the experimental result (162 C). The ductile-to-brittle transition temperature of the weld metal was recovered by no less than 85 %.

Integrated risk assessment for multi-unit NPP sites—A comparison

International Nuclear Information System (INIS)

Kumar, C. Senthil; Hassija, Varun; Velusamy, K.; Balasubramaniyan, V.

2015-01-01

Highlights: • Framework for integrated risk assessment for multi-unit NPP sites. • Categorization of external and internal events. • Modelling of key issues: mission time, cliff-edge, common cause failures, etc. • Safety goals for multi-unit NPP sites. • Comparison of site core damage frequency in one, two, three and four unit sites. - Abstract: Most of the nuclear power producing sites in the world houses multiple units. Such sites are faced with hazards generated from external events: earthquake, tsunami, flood, etc. and can threaten the safety of nuclear power plants. Further, risk from a multiple unit site and its impact on the public and environment was evident during the Fukushima nuclear disaster in March 2011. It is therefore important to evolve a methodology to systematically assess the risk from multi-unit site. For a single unit site, probabilistic risk assessment technique identifies the potential accident scenarios, their consequences, and estimates the core damage frequency that arise due to internal and external hazards. This challenging task becomes even more complex for a multiple unit site, especially when the external hazards that has the potential to generate one or more correlated hazards or a combination of non-correlated hazards are to be modelled. This paper presents an approach to evaluate risk for multiple NPP sites and also compare the risk for sites housing single, double and multiple nuclear plants.

Integrated risk assessment for multi-unit NPP sites—A comparison

Energy Technology Data Exchange (ETDEWEB)

Kumar, C. Senthil, E-mail: cskumar@igcar.gov.in [AERB-Safety Research Institute, Kalpakkam (India); Hassija, Varun; Velusamy, K. [Reactor Design Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Balasubramaniyan, V. [AERB-Safety Research Institute, Kalpakkam (India)

2015-11-15

Highlights: • Framework for integrated risk assessment for multi-unit NPP sites. • Categorization of external and internal events. • Modelling of key issues: mission time, cliff-edge, common cause failures, etc. • Safety goals for multi-unit NPP sites. • Comparison of site core damage frequency in one, two, three and four unit sites. - Abstract: Most of the nuclear power producing sites in the world houses multiple units. Such sites are faced with hazards generated from external events: earthquake, tsunami, flood, etc. and can threaten the safety of nuclear power plants. Further, risk from a multiple unit site and its impact on the public and environment was evident during the Fukushima nuclear disaster in March 2011. It is therefore important to evolve a methodology to systematically assess the risk from multi-unit site. For a single unit site, probabilistic risk assessment technique identifies the potential accident scenarios, their consequences, and estimates the core damage frequency that arise due to internal and external hazards. This challenging task becomes even more complex for a multiple unit site, especially when the external hazards that has the potential to generate one or more correlated hazards or a combination of non-correlated hazards are to be modelled. This paper presents an approach to evaluate risk for multiple NPP sites and also compare the risk for sites housing single, double and multiple nuclear plants.

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

International Nuclear Information System (INIS)

Naydenov, N.; Mignone, O.

2004-01-01

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

Redundant filtration system of the fuel buildings,units 1 and 2 Almaraz NPP

International Nuclear Information System (INIS)

Lopez Tanco, J.

2011-01-01

The project redundant filtering fuel buildings in units 1 and 2 of Almaraz NPP, will compliance to the requirements established in the complementary technical instructions to the authorization of exploitation of Almaraz NPP, established by the CSN and will consist of the installation of a new filtration unit.

NPP Mochovce units 1 and 2 diagnostic systems

International Nuclear Information System (INIS)

Heidenreich, S.

1997-01-01

In this paper the diagnostic systems (leak detection monitoring, vibration monitoring, lose parts monitoring, fatigue monitoring) of NPP Mochovce units 1 and 2 are presented. All of the designed diagnostic systems are personal computer based systems

Decommissioning of Kozloduy NPP units 1÷4 progress and challenges

International Nuclear Information System (INIS)

Kazakov, Momchil

2016-01-01

The process of decommissioning of Units 1 to 4 is under implementation according to the approved schedule and dismantling work in the TH is expected to be completed in due time, i.e. the end of 2018. Management of dismantled materials is difficult due to the lack of licensed sites for management of materials from the decommissioning activities, as well as due to the long free release procedures. In order to solve the above mentioned issues, measures have been taken concerning the design and construction of sites for management of materials from the decommissioning activities and in respect of the release of material from regulatory control. The preparation of the CA and auxiliary buildings for dismantling has started on schedule, as well as the dismantling of potentially contaminated equipment; Management and treatment of decommissioning RAM and RAW will be assisted by putting into operation of the Size Reduction and Decontamination Workshop (SRDW) and Plasma Melting Facility (PMF) which is scheduled for 2017; Management of RAW from the Mortuaries in the CA is another challenge for SERAW and in that regard a Feasibility Study for the Management of “Mogilnik” storages of KNPP Units 1-4 is first planned to be carried out and thereafter a management approach is to be selected; Regarding dismantling in the CA, SERAW is in the process of Elaboration of a Design for Dismantling of Equipment in the Controlled Areas of KNPP Units 1-4; Based on the selected option for dismantling, particularly the Reactor Pressure Vessel (RPV), reactor internals and the rest activated components, the Consultant shall justify by relevant analyses the requirement for temporary storage areas for activated equipment by complying with the best international practices

Balancing preventive and corrective maintenance in Cernavoda Unit 1 NPP

International Nuclear Information System (INIS)

Riedel, M.; Marinescu, S.

2000-01-01

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)

The contract for the completion and commissioning of Cernavoda NPP - Unit

International Nuclear Information System (INIS)

2001-01-01

On May 18, 2001 the commercial contract for the completion and commissioning of the Cernavoda NPP Unit 2 has been signed by Nuclearelectrica National Company (SNN SA) and its partners, AECL-Canada and ANSALDO-Italy. This contract represents a continuation of the cooperation with AECL-Canada (the owner of the licence and the designer of the nuclear part of Cernavoda NPP Unit1) and ANSALDO-Italy (the designer of the conventional part of Cernavoda NPP Unit1). The completion is scheduled to last for 54 months (4.5 years) since the date the contract takes effect and the nuclear reactor start-up (the first criticality) is scheduled for the 49 th month. The total negotiated cost for the completion was estimated to amount to 689 million dollars, against the 750 million dollars initially estimated. The works at the site will be managed by an integrated staff team of specialized personnel form AECL-Canada (111 positions), ANSALDO-Italy (72 positions) and Romania (1200 positions)

Kozloduy Nuclear Power Plant (Unit 1 and 2). Proposed modifications to increase the seismic capability of equipment and main structures

International Nuclear Information System (INIS)

Ordonez Villalobos, A.; Monette, P.R.

1993-01-01

Within the framework of the European Community's PHARE Programme of improvement to facilities, their operating systems, equipment and buildings of the Kozloduy NPP in Bulgaria, plant safety during seismic events is considered to be an issue of overriding importance, especially in view of the earthquakes the region suffered during the last decade. Westinghouse Energy Systems International (WESI) and Empresarios Agrupados (EA) have initiated an intensive programme for physical upgrading of equipment with a view to augmenting its seismic capability and, at the same time, to studying design modifications in the diesel-generator buildings, pump house and main building structures (turbines, electrical building). The implementation of these modifications requires an in situ inspection of the real conditions of the various elements, analyses, conceptual design and detail engineering, all of which has to be done in short periods of time using resources available at the plant. This activity is performed by the companies mentioned above, with the collaboration of two engineering companies, Energoproekt of Bulgaria and INITEC of Spain. This paper describes the activities developed and the treatment given to the various aspects of improvement of the seismic capability of equipment and structures. (author)

Cernavoda NPP Unit 1 - a plant of several generations

International Nuclear Information System (INIS)

Rotaru, I.; Metes, M.; Anghelescu, M.S.

2001-01-01

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)

Analysis of heavy radiological accidents in NPP and gamma-irradiators

Energy Technology Data Exchange (ETDEWEB)

Angelov, V [Civil Defence Administration, Sofia (Bulgaria); Semova, T; Bonchev, Ts [Sofia Univ. (Bulgaria). Fizicheski Fakultet

1996-12-31

A review of several heavy radiological accidents, their cause, character, radioactivity emission, victims and economical impact is presented in the form of uniform tables. Eleven cases of incidents in power plants and 4 cases of accidents involving powerful gamma irradiators are considered. Radiological accidents in Bulgaria, not connected with the Kozloduy NPP, are listed. The human factor has been identified as the main cause for most of the accidents. It is stressed that the probability of heavy accident increases at the time of reactor refuelling, repair or testing. Technical failures could be eliminated by improved check and diagnostics procedures. 2 tabs., 12 refs.

Analysis of heavy radiological accidents in NPP and gamma-irradiators

International Nuclear Information System (INIS)

Angelov, V.; Semova, T.; Bonchev, Ts.

1995-01-01

A review of several heavy radiological accidents, their cause, character, radioactivity emission, victims and economical impact is presented in the form of uniform tables. Eleven cases of incidents in power plants and 4 cases of accidents involving powerful gamma irradiators are considered. Radiological accidents in Bulgaria, not connected with the Kozloduy NPP, are listed. The human factor has been identified as the main cause for most of the accidents. It is stressed that the probability of heavy accident increases at the time of reactor refuelling, repair or testing. Technical failures could be eliminated by improved check and diagnostics procedures. 2 tabs., 12 refs

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

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-01

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. This volume of Working material contains reports related analyses and testing of Kozloduy nuclear power plant, units 5 and 6.

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

International Nuclear Information System (INIS)

1995-01-01

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. This volume of Working material contains reports related analyses and testing of Kozloduy nuclear power plant, units 5 and 6

Assessment of financial expenditure for Rivne NPP power units decommissioning

International Nuclear Information System (INIS)

Nosovskij, A.V.; Salij, L.M.

2007-01-01

The article covers some financial aspects of developing a decommissioning concept for Rivne NPP power units with reactor VVER-440 and VVER-1000. Possible methodological approaches to costs estimate have been analyzed. Preliminary results of cost estimation are presented for two decommissioning options: deferred and immediate dismantling. Principally possible options for accumulating assets have been analyzed to finance measures related to Rivne NPP decommissioning. A mathematical model has been proposed for creating decommissioning financial reserve

Search and Retrieval of Foreign Objects for the Steam Generator of Wolsung NPP Unit 1

Energy Technology Data Exchange (ETDEWEB)

Jeong, Woo-Tae; Lee, Kyung-Ho [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

We developed a foreign object search and retrieval (FOSAR) system for Wolsung NPP unit 1 steam generators. The steam generators of Wolsung NPP unit 1 have one 2.5 inch hand hole and two 4 inch hand holes. The FOSAR system was designed to be installed through 4 inch hand holes. Using permanent magnet, the FOSAR system was firmly attached to the vertical annulus wall of the steam generator. We successfully developed the FOSAR system for Wolsung NPP unit 1. Using the developed FOSAR system, technicians successfully found and removed various foreign objects. Most of the foreign objects, we found, were made of carbon steel sheet, therefore magnet tool was the most useful to remove it. Alligator tool was sometimes used. Based on the experience during the FOSAR activities, we are developing a lancing system for Wolsung NPP unit 1. It will be designed and manufactured until November 2016.

Search and Retrieval of Foreign Objects for the Steam Generator of Wolsung NPP Unit 1

International Nuclear Information System (INIS)

Jeong, Woo-Tae; Lee, Kyung-Ho

2016-01-01

We developed a foreign object search and retrieval (FOSAR) system for Wolsung NPP unit 1 steam generators. The steam generators of Wolsung NPP unit 1 have one 2.5 inch hand hole and two 4 inch hand holes. The FOSAR system was designed to be installed through 4 inch hand holes. Using permanent magnet, the FOSAR system was firmly attached to the vertical annulus wall of the steam generator. We successfully developed the FOSAR system for Wolsung NPP unit 1. Using the developed FOSAR system, technicians successfully found and removed various foreign objects. Most of the foreign objects, we found, were made of carbon steel sheet, therefore magnet tool was the most useful to remove it. Alligator tool was sometimes used. Based on the experience during the FOSAR activities, we are developing a lancing system for Wolsung NPP unit 1. It will be designed and manufactured until November 2016

Conceptual Design of a Combined Power Generation Unit at the NPP Seaside

International Nuclear Information System (INIS)

Cha, Kyung H.

2011-01-01

In order to improve operational performance, an undersea tunnel is being utilized for in-taking and out-taking seawater as coolant in Nuclear Power Plant (NPP). This paper describes a Combined solar-wind-wave Power Generation Unit (CPGU) to be specialized for in-taking and out-taking seawater as coolant in NPP. Accordingly, the purpose of the CPGU is twofold: one is to contain some tunnels to be maintained on the bottom of the CPGU body in order to in-take and out-take coolant water, and the other is to generate a combined power at the NPP seaside. Fig. 1 shows the conceptual CPGU to be configured at the NPP seaside

Project for qualification of the Kozloduy confinement system; Proyecto de cualificacion del sistema de confinamiento de Kozloduy

Energy Technology Data Exchange (ETDEWEB)

Montes Rodriguez, J L [Empresarios Agrupados, A.I.E., Madrid (Spain)

1993-12-15

One of the projects awarded to Empresarios Agrupados within the Six-Month WANO Programme for Kozloduy NPP, financed through the European Community's PHARE Programme, relates to the first tasks of plant confinement system qualification. Development of this project - the results of which will serve as a reference for other power plants with VVER-440/230 models - aroused considerable interest in the Bulgarian nuclear community as well as in international entities which render assistance to Eastern power plants. In fact, this is one of the few projects in the programme which takes into account hardware-oriented activities to be carried out urgently in the plant. The VVER-440/230 confinement system performs functions parallel to the containment system of Western PWR reactors. However, it differs significantly in its criteria and operation details. These important differences form the basis for a rational and prudent application of the essence of Western codes and standards relating to the qualification of these systems. The criteria which are developed to make this application viable constitute the most challenging and, at the same time, most risky part of this job. The project will be in its final stages when the 18th Annual Meeting of the Spanish Nuclear Society is held; it is therefore likely that this paper will advance the results and conclusions expected. (author)

Kozloduy Nuclear Power Plant (Unit 1 and 2). Proposed modifications to increase the seismic capability of equipment and main structures; Central Nuclear de Kozloduy (Unidades 1 y 2). Modificaciones propuestas a los equipos y estructuras principales para incrementar su capacidad sismica

Energy Technology Data Exchange (ETDEWEB)

Ordonez Villalobos, A [Empresarios Agrupados, A.I.E., Madrid (Spain); Monette, P R [Westinghouse Energy Systems International (WESI), Bussels (Belgium)

1993-12-15

Within the framework of the European Community's PHARE Programme of improvement to facilities, their operating systems, equipment and buildings of the Kozloduy NPP in Bulgaria, plant safety during seismic events is considered to be an issue of overriding importance, especially in view of the earthquakes the region suffered during the last decade. Westinghouse Energy Systems International (WESI) and Empresarios Agrupados (EA) have initiated an intensive programme for physical upgrading of equipment with a view to augmenting its seismic capability and, at the same time, to studying design modifications in the diesel-generator buildings, pump house and main building structures (turbines, electrical building). The implementation of these modifications requires an in situ inspection of the real conditions of the various elements, analyses, conceptual design and detail engineering, all of which has to be done in short periods of time using resources available at the plant. This activity is performed by the companies mentioned above, with the collaboration of two engineering companies, Energoproekt of Bulgaria and INITEC of Spain. This paper describes the activities developed and the treatment given to the various aspects of improvement of the seismic capability of equipment and structures. (author)

NPP Decommissioning: the concept; state of activities

International Nuclear Information System (INIS)

Nemytov, S.; Zimin, V.

2001-01-01

The main principles of NPP decommissioning concept in Russia are given. The conditions with fulfillment of works on NPP unit pre-decommissioning and decommissioning including: development of the normative documentation, creation of special fund for financing NPP decommissioning activities, deriving the Gosatomnadzor license for decommissioning of shut down NPP units, development of the equipment and technologies for waste and spent fuel management are presented. The decommissioning cost and labour intensity of one WWER-440 unit are shown. The practical works, executed on shut down units at Beloyarsk NPP (Unit1 and 2) and Novo Voronezh NPP (Unit 1 and 2) are outlined

Cernavoda NPP Unit 1 - a plant of several generations

International Nuclear Information System (INIS)

Rotaru, I.; Metes, M.; Anghelescu, M.S.

2000-01-01

Cernavoda NPP Unit 1, the first nuclear power unit in Romania, has a long and tormented history. It represents a rather unique case in Eastern Europe. The project started well before 1989 (the construction phase lasted 17 years and generations were involved in its completion), but it is effectively based on western technology (Candu). Meanwhile, the national nuclear program underwent many changes, affecting the lives and careers of Romanian nuclear professionals. Finally, on December 2 nd 1996, the unit began its c ommercial operation , being operated at its nominal power rating of 706 MW e . It now provides a reliable source of electricity for Romanian economy, supplying to the national grid about 10% of the country's average annual demand. The paper reflects some aspects related to the shift of generations during the project's development, including the present stage. The operational performances achieved 'in service' by Cernavoda NPP Unit 1 up to the end of 1999 , are also presented. Reference to the electrical energy production, performance indicators, production costs, nuclear safety, radiation protection, radioactive wastes, nuclear fuel consumption and nuclear fuel performances are included. Comparisons are performed with similar indicators reported by other worldwide nuclear power plants, in order to assess our results. (authors)

Calculation of the real states of Ignalina NPP Unit 1 and Unit 2 RBMK-1500 reactors in the verification process of QUABOX/CUBBOX code

International Nuclear Information System (INIS)

Bubelis, E.; Pabarcius, R.; Demcenko, M.

2001-01-01

Calculations of the main neutron-physical characteristics of RBMK-1500 reactors of Ignalina NPP Unit 1 and Unit 2 were performed, taking real reactor core states as the basis for these calculations. Comparison of the calculation results, obtained using QUABOX/CUBBOX code, with experimental data and the calculation results, obtained using STEPAN code, showed that all the main neutron-physical characteristics of the reactors of Unit 1 and Unit 2 of Ignalina NPP are in the safe deviation range of die analyzed parameters, and that reactors of Ignalina NPP, during the process of the reactor core composition change, are operated in a safe and stable manner. (author)

Utilization of the residual water resource from the Kozloduy NPP's hot channel for building a small hydropower plant (TK1)

International Nuclear Information System (INIS)

Tolev, T.

2004-01-01

A hydropower plant built on the hot channel of the NPP should be capable to utilise the whole changing water flow from the NPP cooling system. Tree factors - level of the hot channel, level of the Danube river and the water flow - determine the power potential of the HPP. The water level in the hot channel varies between 31.20 and 32.50 m with an optimum at 31.50 m. The Danube river level varies in a wide range. The head at 85% of the river level and at a level of the channel 31.50 m is 7.2 m. The water flow depends on the NPP operation and it is between 45 m 3 /s and 140 m 3 /s. Thus the nominal power of the HPP is 5 740 kW. The construction of the HPP is justified in case of at least 30 years of operation. The calculations are made for the operation of units 5 and 6 which are expected to work during this period. A significant role for the maximal utilisation of the resource of the hot channel plays the choice of the hydro-turbines. The horizontal PIT-Kaplan turbines are considered as the most appropriate. The integrating of the plant into the electric network and possible impact on the environment are also considered

Financing Nuclear Projects. Case Study: Unit 2 Cernavoda NPP

International Nuclear Information System (INIS)

Chirica, Teodor; Constantin, Carmencita; Dobrin, Marian

2003-01-01

The implementation of a Nuclear Power Plant (NPP) is a major undertaking for all entities involved, due to the necessity of planning work and coordination of the implementation process of the different fields of interest, starting with the governmental authorities and ending with the public. Having in view the specific investment costs (relatively high) for a NPP, finding an adequate financing structure is possible through an iterative process that involves first an assessment of the technical performances of the project and secondly, the mathematical modelling of the financing structure effects on the projects. In this respect, the paper 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 documentation requested by the local and international authorities to promote the project and ending with the negotiation of the contracts (commercial contract, financing contract, purchase contract, etc). The case study will be focused on the phases achieved in order to promote the Unit 2 NPP Cernavoda completion works project. (authors)

Financing nuclear projects. Case study: Unit 2 Cernavoda NPP

International Nuclear Information System (INIS)

Chirica, T.; Pall, S.; Lebedev, A.; Dobrin, M.

2003-01-01

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)

Nuclear power: the political challenge

International Nuclear Information System (INIS)

Adam, G.

2009-01-01

A brief overview of the political and economical situation and nuclear energy problems in Europe is given. The author presented his opinion on topic such as need of nuclear power, Kozloduy NPP units 1-4 shutdown, climate change , energy security, environmental problems

Qualitative and quantitative methods for human factor analysis and assessment in NPP. Investigations and results

International Nuclear Information System (INIS)

Hristova, R.; Kalchev, B.; Atanasov, D.

2005-01-01

We consider here two basic groups of methods for analysis and assessment of the human factor in the NPP area and give some results from performed analyses as well. The human factor is the human interaction with the design equipment, with the working environment and takes into account the human capabilities and limits. In the frame of the qualitative methods for analysis of the human factor are considered concepts and structural methods for classifying of the information, connected with the human factor. Emphasize is given to the HPES method for human factor analysis in NPP. Methods for quantitative assessment of the human reliability are considered. These methods allow assigning of probabilities to the elements of the already structured information about human performance. This part includes overview of classical methods for human reliability assessment (HRA, THERP), and methods taking into account specific information about human capabilities and limits and about the man-machine interface (CHR, HEART, ATHEANA). Quantitative and qualitative results concerning human factor influence in the initiating events occurrences in the Kozloduy NPP are presented. (authors)

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

International Nuclear Information System (INIS)

Halada, P.; Cillik, I.; Stojka, T.; Kuzma, M.; Prochaska, J.; Vrtik, L.

2004-01-01

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)

Increase nuclear safety of WWER-440

International Nuclear Information System (INIS)

Nochev, T.; Sabinov, S.

2000-01-01

A complete program for increasing nuclear safety has been made at NPP Kozloduy with the participation of German, French, Russian and American specialists. This effort cost greater than 100 mil $. This report includes the methods of increasing nuclear safety. The style of management in NPP Kozloduy has been changed for the last seven years. (authors)

The future of Bulgarian nuclear sector

International Nuclear Information System (INIS)

Iordanov, I.; Yankov, I.

2012-01-01

The problems of the Bulgarian nuclear energy sector in Bulgaria and possible solutions are presented. The priorities are summarized as: extension of life for units 5 and 6 in NPP Kozloduy establishing of contacts with producers of SMR long‐term strategy for Bulgarian energy sector

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 2B. General material: codes, standards, criteria. Working material

International Nuclear Information System (INIS)

1999-01-01

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

Project for qualification of the Kozloduy confinement system

International Nuclear Information System (INIS)

Montes Rodriguez, J.L.

1993-01-01

One of the projects awarded to Empresarios Agrupados within the Six-Month WANO Programme for Kozloduy NPP, financed through the European Community's PHARE Programme, relates to the first tasks of plant confinement system qualification. Development of this project - the results of which will serve as a reference for other power plants with VVER-440/230 models - aroused considerable interest in the Bulgarian nuclear community as well as in international entities which render assistance to Eastern power plants. In fact, this is one of the few projects in the programme which takes into account hardware-oriented activities to be carried out urgently in the plant. The VVER-440/230 confinement system performs functions parallel to the containment system of Western PWR reactors. However, it differs significantly in its criteria and operation details. These important differences form the basis for a rational and prudent application of the essence of Western codes and standards relating to the qualification of these systems. The criteria which are developed to make this application viable constitute the most challenging and, at the same time, most risky part of this job. The project will be in its final stages when the 18th Annual Meeting of the Spanish Nuclear Society is held; it is therefore likely that this paper will advance the results and conclusions expected. (author)

Reliability analysis of the reconstructed safety systems of the Kozloduy-2 WWER-440/V-230 reactor

Energy Technology Data Exchange (ETDEWEB)

Kalchev, B [Energoproekt, Sofia (Bulgaria)

1996-12-31

The Unit 2 of the Kozloduy NPP started operations in 1975. As it is designed according to safety standards of the middle sixties, it needs reconstruction in order to prolong its operational life up to the design age of 30 years, in agreement with the increased safety requirements in Bulgaria. The reliability analyses of front line systems of the unit are performed to this end. The approach taken in the study is the fault tree methodology to determine the unavailability of each system. Common mode failures are considered for the pumps and valves using the beta factor method. The mission time for each system is 24 hours and the test period is 720 hours. Support systems and human errors are also included. All the systems control and instrumentation signals are modelled explicitly in the fault trees. The generic IDEA reliability data base is used for all quantifications. The initiating events that would require the system operation are presented and on this basis the thermohydraulic analysis success criteria for each system are determined. The code for probabilistic safety assessment PSAPACK is used. Fault trees for the following front line safety systems are constructed: the high pressure injection system, the spray system and the auxiliary feed water system. The analysis consider some proposed decisions for reconstruction. The results show that the reliability of these systems has increased after reconstruction and the safety has been upgraded. This decrease the core damage frequency from 3.53E{sup -3}, 1/RY to 1.07E{sup -3}, 1/RY. 5 refs., 2 tabs., 5 figs.

Reliability analysis of the reconstructed safety systems of the Kozloduy-2 WWER-440/V-230 reactor

International Nuclear Information System (INIS)

Kalchev, B.

1995-01-01

The Unit 2 of the Kozloduy NPP started operations in 1975. As it is designed according to safety standards of the middle sixties, it needs reconstruction in order to prolong its operational life up to the design age of 30 years, in agreement with the increased safety requirements in Bulgaria. The reliability analyses of front line systems of the unit are performed to this end. The approach taken in the study is the fault tree methodology to determine the unavailability of each system. Common mode failures are considered for the pumps and valves using the beta factor method. The mission time for each system is 24 hours and the test period is 720 hours. Support systems and human errors are also included. All the systems control and instrumentation signals are modelled explicitly in the fault trees. The generic IDEA reliability data base is used for all quantifications. The initiating events that would require the system operation are presented and on this basis the thermohydraulic analysis success criteria for each system are determined. The code for probabilistic safety assessment PSAPACK is used. Fault trees for the following front line safety systems are constructed: the high pressure injection system, the spray system and the auxiliary feed water system. The analysis consider some proposed decisions for reconstruction. The results show that the reliability of these systems has increased after reconstruction and the safety has been upgraded. This decrease the core damage frequency from 3.53E -3 , 1/RY to 1.07E -3 , 1/RY. 5 refs., 2 tabs., 5 figs

Demographic and health characteristics of the population residing within the 30-km area around the Kozloduy NPP

International Nuclear Information System (INIS)

Dimitrov, P.; Bliznakov, V.

1993-01-01

Based on detailed analysis of data on demographic and health state of the population residing within the 30-km zone around the Kozloduj NPP, an attempt was made to detect any impact of the power plant on population health under normal NPP operational conditions. The health characteristics of the population revealed no unfavorable trends. Particular attention was given to diseases of the blood and blood-forming organs, malignant new growths, complications of pregnancy, and congenital anomalies. (author)

The analysis in real time, during the pre-commissioning period, of the overall plant control system of the CANDU NPP unit

International Nuclear Information System (INIS)

Tapu, C.; Irimia, M.

1994-01-01

The physical processes in the CANDU NPP are controlled by a computer system which, based on the associated package of programmes, performs both the monitoring function at the level of the operational area, and the digital regulation function of the technological systems within the NPP. For an optimal operation of the NPP, in dynamic as well as in stationary regime, the correlation of the direct digital control of the technological systems is very important for the NPP's overall digital control system. Taking into account the fact that during the pre-commissioning period of a CANDU unit it is necessary to test in dynamic regime the performance of the overall digital control function of the NPP, a system of verification and testing in real time was developed, by connecting a micro simulator of the physical process in the NPP to the actual computer system of the unit. The paper presents the methods and techniques used, as well as the results of the tests for various operational modes, which highlight the functioning of the digital control system of the CANDU NPP unit. (Author)

Fuel assembly leakage, unit 4, cycle 22, Paks NPP

International Nuclear Information System (INIS)

Szecsenyi, C.; Burjan, T.; Torma, B.; Bona, G.

2009-01-01

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 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)

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

International Nuclear Information System (INIS)

Szecsenyi, Z.; Burjan, T.; Torma, B.; Bona, G.

2009-01-01

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)

Specific aspects for Cernavoda - Unit 1 NPP life assurance

International Nuclear Information System (INIS)

Rucareanu, R.

2002-01-01

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

Atomic Questions Group peer review mission to Bulgaria

International Nuclear Information System (INIS)

Vapirev, E.; Georgiev, J.; Sabinov, S.

2004-01-01

The objective of the Atomic Questions Group (AQG) peer review mission (17-19 Nov 2003) was to monitor the status of the recommendations contained in the 2001 Report on Nuclear Safety in the Context of Enlargement focusing specifically those recommendations identified in the 2002 Peer Review Status Report as requiring further attention or monitoring. Most AQG/WPNS 2001 recommendations were found as adequately addressed with the exception of the following to which Bulgaria was expected to devote further attention: 2nd General Recommendation NPP type I regarding Safety Analysis Reports (SARs); 1st Specific Recommendation NPP type I regarding the new nuclear legislation; 1st General Recommendation Other Nuclear Installations type II regarding the storage of radioactive waste. In addition WPNS recommended further monitoring of the following commitments: 1st General Recommendation NPP type I regarding the plant specific safety improvement programmes - to ensure that the programmes are completed in accordance with the plans; 2nd General Recommendation NPP type I regarding Safety Analysis Reports (SARs) - to ensure that the SARs are completed in accordance with the plans; 2nd General Recommendation NPP type I regarding Emergency Operating Procedures (EOPs) - to ensure the completion of work on EOPs in accordance with the plans and so that these provide for the development of appropriate guidance on the management of beyond design basis accidents; 2nd Specific Recommendation NPP type I regarding the resources of the regulator - to ensure that adequate human and financial resources will be provided according to the developed plan; 5th Specific Recommendation NPP type I regarding the implementation of specific upgrading improvements at Kozloduy units 3 and 4- to specifically follow these items during the monitoring associated with 1st General recommendation NPP type I, Upgrading programme; 6th Specific Recommendation NPP type I regarding high-energy pipe breaks at Kozloduy

Fukushima – Impact on the Industry

International Nuclear Information System (INIS)

2012-01-01

The response to the accident is presented. European Stress Tests Peer Review Report is presented. The Worley Parsons Stress Test Experience includes performing “Stress tests” for Kozloduy NPP and Performing “design stress tests” : in Bulgaria – A92; Russia – AES 2006; Turkey – AES 2006. Nuclear energy outlook includes the Germany case and an overview of main activities in Europe: Finland - Two active projects (one greenfield site); Both approved by government Sweden - On-going project for replacement power Poland - Site characterization for first NPP on its way Lithuania -Final negotiations with GE-Hitachi Czech Republic - Tender for 2 new Temelin units due July 2; Bulgaria - Switch from Belene to Kozloduy UK – Government passing of new legislation to give investment security France -Committed to Flammanville and Penly; Policy change of new government questionable

Status and prospects of WWER in-core fuel management activities

International Nuclear Information System (INIS)

Novikov, A.N.; Pavlov, V.I.; Pavlovichev, A.M.; Proselkov, V.N.; Saprykin, V.V.

1994-01-01

A short review is given of recent extensive calculational and experimental studies carried out in Russia and Bulgaria for WWER fuel cycle modernization. The main activities performed at Kola NPP, Novovoronezh NPP, Kozloduy NPP and Balakovo NPP are outlined. Based on experience gained, the following improvements in the fuel cycle have been introduced: 1) increased fuel burnup; 2) reduced natural uranium consumption and decreased amount of separation work per energy output unit; 3) increased efficiency of the reactor emergency protection; 4) reduced fast neutron flux onto the reactor vessel. The main characteristics of modernized fuel cycles of WWER-440 and WWER-1000 are presented. 4 tabs., 3 figs., 14 refs

Status and prospects of WWER in-core fuel management activities

Energy Technology Data Exchange (ETDEWEB)

Novikov, A N; Pavlov, V I; Pavlovichev, A M; Proselkov, V N; Saprykin, V V [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)

1994-12-31

A short review is given of recent extensive calculational and experimental studies carried out in Russia and Bulgaria for WWER fuel cycle modernization. The main activities performed at Kola NPP, Novovoronezh NPP, Kozloduy NPP and Balakovo NPP are outlined. Based on experience gained, the following improvements in the fuel cycle have been introduced: (1) increased fuel burnup; (2) reduced natural uranium consumption and decreased amount of separation work per energy output unit; (3) increased efficiency of the reactor emergency protection; (4) reduced fast neutron flux onto the reactor vessel. The main characteristics of modernized fuel cycles of WWER-440 and WWER-1000 are presented. 4 tabs., 3 figs., 14 refs.

NPP Cernavoda Unit 2 Financing Completion Works

International Nuclear Information System (INIS)

Chirica, T.; Stefanescu, A.; Constantin, C.; Dobrin, M.

2002-01-01

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)

Some problems connected with the Chernobyl NPP Unit 4 Accident

International Nuclear Information System (INIS)

Bar'yakhtar, V.G.

1994-01-01

The description of the eruption of radionuclides caused by the Chernobyl NPP Unit 4 Accident, including the effective time of the accident, quality and quantity of radio waste, is presented. A particular attention is given to the spotty structure of Chernobyl's contamination. The assumption that the spots distribution may be a consequence of the turbulent processes in the atmosphere is made

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 5C. Experience data. Working material

International Nuclear Information System (INIS)

1999-01-01

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

The Information System for Operational Activity Organization as a Tool for Configuration Management in NPP

International Nuclear Information System (INIS)

Manchev, B. L.; Yordanova, V. S.; Nenkova, B. G.

2008-01-01

The Configuration Management (CM) is an integrated management process by means of which conformity between design requirements, physical configuration and the plant documentation is ascertained. This conformity is maintained during the entire life cycle of the facility. CM ensures that during the entire operational life of the plant the following requirements are met: The basic design requirements of the plant are established, documented and maintained; The physical structures, systems and components (SSC) of the plant are in conformity with the design requirements; The physical and functional characteristics of the plant are correctly incorporated in the operational documentation and the documentation for repair, as well as in the documents for tests and training; The changes in the design documentation are incorporated in the physical configuration and the operative documentation; The changes in the design are minimized by management process for review according to approved criteria; The changes proposed in the equipment and documentation of the plant are estimated entirely with the purpose of determining their effect and are reviewed and approved by appropriate managing staff before their introduction. The information system for organization of the operational activity (IS OOA) consists of several modules used for storage and retrieval of data for different aspects of the operation of the equipment at the site of Kozloduy NPP, as defects and failures, design requirements and bases, design data and characteristics, tests, life time, maintenance and repair, as well as changes in the design or the design documentation. IS OOA consists of single relational database and provides built-in connections to the database of the SmartDoc system for control of the documentation, as well as to the database for human resources. Central place in IS OOA is taken by the 'Equipment' module while all other modules are connected with the identification data of the structures

Determining permissible PT parameters in normal operating conditions for reactor pressure vessel of units 1-4 of NPP Kozloduy

International Nuclear Information System (INIS)

Batischev, M.; Yurukov, V.; Simovski, Ts.

2000-01-01

The main objective of the analysis is to verify the determined from the Main Designer P-T curves and to provide that permissible T values can be decreased even in case a lot of very conservative assumptions are taken into account. Detailed temperature and stress distributions are obtained using different 3D Finite Element Models. Then, assuming linear elastic behaviour and using these distributions onto models including cracks K I values are determined. From the K I values taking into account material characteristics and actual and prognostic neutron fluence of the most sensitive areas of the RPV, P-T curves are determined. Residual stresses in welds are also taken into account. Analysis has been performed independently following two different methodologies - one prescribed by Russian norms (PNAEh-G-7-002-86) and another, developed by the IAEA - 'Guidelines on PTS analysis for WWER NPP'. The obtained results using two methodologies are compared and the more severe are determined

Status and objectives of the Bulgarian nuclear energy sector

International Nuclear Information System (INIS)

Kouzmanov, K.

1996-01-01

A brief overview of the current situation and problems to be solved in the Bulgarian nuclear energy is presented. The main task is to increase the availability of the Kozloduy NPP in terms of time and power. The following technical solutions for reconstruction of units 1-4 (WWER-440) are discussed: defence against external events; emergency cooling of the primary and secondary circuits; reliability analysis used in probabilistic safety assessment; management of beyond design basis accident conditions. The necessity of retrofitting of units 5-6 (WWER-1000) and completion of the Belyane NPP project is also stressed

Soil-structural interaction analysis of RBMK type NPP for seismic event. Progress report. From 1 July 1998 - 30 June 1999

International Nuclear Information System (INIS)

1999-01-01

The objective of the project is to assess the structural behavior and safety capacity of a RBMK-1000 MW Main Building Complex under critical combination of loads including seismic events. This project is part of the Coordinated Research Program carried out by International Atomic Energy Agency on safety of RBMK Type Nuclear Power Plants (NPP) in Relation to External Events. The nuclear power plant considered for this study is the Sosnovy Bor NPP, located near St.Petersburg, Russia. The Soviet standard design RBMK-1000 MW type units installed in Sosnovy Bor NPP were originally designed for a Safe Shutdown Earthquake (SSE) with a peak ground acceleration (PGA) of 0.1 g. The relevant response spectra are not available for reference and assessment. The new international requirements for nuclear power plants in operation require site specific seismic hazard studies as a basis for the definition of a Review Level Earthquake (RLE) for reassessment of the structures and safety related equipment Ell - As the RLE site specific seismic data is still not available, the RLE earthquake spectra for Kozloduy NPP scaled to PGA=0.1 g were used in this study. This value is intentionally chosen for comparison purposes. The Russian design requirements (if design floor response spectra are available) will be compared with the international regulations. The scope of the study is to perform a Soil-Structure Interaction (SSI) seismic response analysis of the referenced RBMK-11000 MW. Main Building Complex to evaluate the effect on the structural response of a greater than design earthquake. The analysis is focused on a realistic assessment of the structural response to a potentially higher earthquake level instead of a conservative design type analysis. Special attention is paid on the seismic response of the sub-structures in the safe shutdown path, as well as on the locations of the heavy equipment

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 4B. Paks NPP: Analysis/testing. Working material

International Nuclear Information System (INIS)

1995-01-01

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 dynamic study of the main building of the Paks NPP; shake table investigation at Paks NPP and the Final report of the Co-ordinated Research Programme

Opening address; Allocution d`ouverture

Energy Technology Data Exchange (ETDEWEB)

Carle, R

1996-12-31

In this opening address the president of WANO underlines the relative isolation of the Kozloduy NPP from the international nuclear community due to the lack of information and contacts. The need for eliminating the isolation is stressed and the following measures are proposed: to make the Kozloduy NPP an active member of the international community; to improve and maintain the safety level; to contribute to the electricity exchange system of Southeastern Europe.

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

International Nuclear Information System (INIS)

Rotaru, Ioan; Jelev, Adrian

2003-01-01

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

Fuel assembly leak tightness control on WWER-1000 reactor

International Nuclear Information System (INIS)

Ivanova, R.; Gerchev, N.; Mateev, A.

2001-01-01

The main index for integrity of the fuel rods cladding is the specific activity value of the primary coolant. This value determines the safe operation of the reactor. The limit for safe operation of WWER-1000 reactor is the value of the total activity of Iodine isotopes in the primary coolant 5.0x10 -3 Ci/l. The paper briefly describes the methodology for performing a fuel tightness test (sipping test) and shows the results from these tests performed during the period 1987 -1999 in units 5 and 6 at the Kozloduy NPP. An additional index related to the safe operation is defined to characterize the fuel cladding integrity Fuel Reliability Index (FRI). The FRI is defined as value of the average activity of 131 I in the primary coolant, corrected with a part of precipitated 235 U migration and fixed to the general permanent purification frequency. Two criteria (quantitative and statistic) are determined to qualify the fuel cladding integrity. The results from sipping tests show good reliability of the fuel irradiated in unit 5 and 6 at the Kozloduy NPP

Life extension program of KORI Unit 1 NPP in Korea

International Nuclear Information System (INIS)

Hong, Sun-Yull

1998-01-01

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

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

International Nuclear Information System (INIS)

Wendt, Dipl-Ing. Ruediger; Kim, Duill; Sik, Cho Hong

2008-01-01

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 15,587m 2 . 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

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

International Nuclear Information System (INIS)

Anon

2007-09-01

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

International technical assistance example. Consortium action in Bulgaria

International Nuclear Information System (INIS)

Mattei, J.M.; Milhem, J.L.

1993-03-01

The safety status achieved last year at the Kozloduy Nuclear Power Plant (NPP) and the capability of the Bulgarian Nuclear Safety Authority (BNSA) to assess the safety of the plant and the adequacy of proposed improvements have been matters of international concern. However, the Kozloduy NPP contributes 35-40 per cent of the electrical generating capacity in Bulgaria. For further operation of the plants, it is therefore, essential that safety is improved. In july 1991, the Commission of the European Communities (CEC) instituted a Six Months Emergency Action Programme for Bulgaria under the PHARE regional nuclear safety programme. The programme consisted of three parts: - an industrial emergency programme supporting the utility of the Kozloduy NPP, - a study to evaluate Bulgaria's electricity needs, - technical assistance for reinforcement of the Bulgarian Nuclear Safety Authority. For the third part, complementary to the industrial emergency programme carried out by the WANO (World Association of Nuclear Operators), a Consortium of expert institutions and regulatory from EC member states was established by CEC for assistance to BNSA. The Consortium consisted of: - Institut de Protection et de Surete Nucleaire (IPSN), France, technical support of the French regulatory body, - Gesellschaft fur Anlagen und Reaktorsicherheit (GRS) mbH, Germany, an organization in safety engineering, technical support of governmental regulatory body, - AIB-Vincotte Nuclear (AVN), Belgium, the organization authorized by the Belgian Government for licensing and inspection of nuclear power plants, - UK Atomic Energy Authority (AEA Technology), an independent UK Government owned nuclear R and D and consultancy organization, - Nuclear Installations Inspectorate (NII) of the Health and Safety Executive, United Kingdom, the nuclear regulatory body for the United Kingdom

International technical assistance example. Consortium action in Bulgaria; Exemple d`assistance internationale. Cas de la Bulgarie, action du consortium

Energy Technology Data Exchange (ETDEWEB)

Mattei, J M; Milhem, J L [CEA Centre d` Etudes de Fontenay-aux-Roses, 92 (France). Inst. de Protection et de Surete Nucleaire; Heuser, F W; Kelm, P [Gesellschaft fuer Reaktorsicherheit mbH (GRS), Koeln (Germany)

1993-03-01

The safety status achieved last year at the Kozloduy Nuclear Power Plant (NPP) and the capability of the Bulgarian Nuclear Safety Authority (BNSA) to assess the safety of the plant and the adequacy of proposed improvements have been matters of international concern. However, the Kozloduy NPP contributes 35-40 per cent of the electrical generating capacity in Bulgaria. For further operation of the plants, it is therefore, essential that safety is improved. In july 1991, the Commission of the European Communities (CEC) instituted a Six Months Emergency Action Programme for Bulgaria under the PHARE regional nuclear safety programme. The programme consisted of three parts: - an industrial emergency programme supporting the utility of the Kozloduy NPP, - a study to evaluate Bulgaria`s electricity needs, - technical assistance for reinforcement of the Bulgarian Nuclear Safety Authority. For the third part, complementary to the industrial emergency programme carried out by the WANO (World Association of Nuclear Operators), a Consortium of expert institutions and regulatory from EC member states was established by CEC for assistance to BNSA. The Consortium consisted of: - Institut de Protection et de Surete Nucleaire (IPSN), France, technical support of the French regulatory body, - Gesellschaft fur Anlagen und Reaktorsicherheit (GRS) mbH, Germany, an organization in safety engineering, technical support of governmental regulatory body, - AIB-Vincotte Nuclear (AVN), Belgium, the organization authorized by the Belgian Government for licensing and inspection of nuclear power plants, - UK Atomic Energy Authority (AEA Technology), an independent UK Government owned nuclear R and D and consultancy organization, - Nuclear Installations Inspectorate (NII) of the Health and Safety Executive, United Kingdom, the nuclear regulatory body for the United Kingdom.

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

International Nuclear Information System (INIS)

Choi, C.H. . E-mail : chechee@khnp.co.kr

2005-01-01

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)

Bohunice V1 NPP upgrading programme

International Nuclear Information System (INIS)

Kerak, J.

2001-01-01

The paper describes whole process of Bohunice V1 NPP nuclear safety and operational reliability level increase which has been performed since units commissioning (1. unit in 1978, 2. unit in 1980), continued Small Reconstruction (1991 -1993) and finished Gradual Upgrading(1994 -2000). The main purpose is to last stage -Gradual upgrading of Bohunice V1 NPP. (author)

The V-1 NPP and V-2 NPP upgrading

International Nuclear Information System (INIS)

1998-01-01

A brief account of activities in the V-1 NPP and V-2 NPP upgrading as well as maintenance carried out by the Nuclear power plants Jaslovske Bohunice in 1997 is presented. The V-1 NPP applied the so called 'Small Backfitting Programme'covering 81 points of the Czechoslovak Atomic energy Commission Decree No 5/91. Continual upgrading continued after the Backfitting Programme completion with the Safety Report and following Nuclear Regulatory Authority of Slovak Republic (NRA SR) Decrees No 1/94 and 110/94 setting spheres and procedure for adopting and implementation of measures enabling the units to operate further on. Results of expert missions, analyses and assessments of components identified by Basic Engineering became the basis for the development of the Gradual Reconstruction Programme. The Programme outputs underwent economic and probabilistic assessing their contribution to nuclear safety. This process resulted in finalizing the Gradual Reconstruction Programme which started to be implemented in 1996 and will be completed in 1999. It is implemented by the REKON consortium and covers 17 areas including Instrumentation and Control, self-consumption emergency supply, leakage monitoring, emergency core cooling system, seismic reinforcement and radioactivity localisation. Both units will reach internationally acceptable safety standards for the remaining life-time period. The V-2 NPP Upgrading and Safety Enhancement Programme includes results of activities performed in the course of last years to define all important activities leading to enhancement of nuclear safety and performance reliability and effectiveness within the plant life-time period and to establish conditions for extending the life-time of these units for 40 years. The V-2 NPP Upgrading and Safety Enhancement Programme aims to assure safe operation with a probability of the core damages less than 10 -4 /reactor · year

Prestart-up hydrogen peroxide solution washing of NPP unit with the RBMK-type reactor

International Nuclear Information System (INIS)

Gruzdev, N.I.; Man'kina, N.N.; Al'tshuller, M.A.

1979-01-01

Presented are the results of industrial hydrogen peroxide solution washing of condensating-feed system conducted on the second unit of the Kursk NPP. Duration of the washing constituted 8 hours. The hydrogen peroxide concentration during first 4 hours was 10-20 mg/kg at a flow rate of 260 m 2 /h, during the following 4 hours it constituted 2-5 mg/kg at a flow rate of 1000 m 3 /h. It is found out that prestart-up hydrogen peroxide washing of NPP power units with the RBMK-type reactor permits: to simplify essentially the technology and scheme of washing process; to reduce a flow rate of desalt washing water; to except environmental contamination with washing solutions and reagents being neutralized; to reduce the time of washing process; to reduce the time necessary for the achievement of reference water condition factors, and to increase the unit reliability and to improve a radiation situation

Behavior of antimony isotopes in the primary coolant of WWER-1000-type nuclear reactors in NPP Kozloduy during operation and shutdown

International Nuclear Information System (INIS)

Dobrevski, Ivan D.; Zaharieva, Neli N.; Minkova, Katia F.; Gerchev, Nikolay B.

2009-01-01

This paper focuses on the behavior of the antimony isotopes 122 Sb and 124 Sb in the coolant of the WWER reactors in the nuclear power plant Kozloduy (Bulgaria) during operation and shutdown. It is concluded that the chemical properties of their actual precursor, the isotope 121 Sb, determine the behavior of 122 Sb and 124 Sb during operation, load fluctuations, and shutdown as well as during the reactor coolant purification process. It is supposed that differences between the reactor bulk and the core fuel cladding surface chemistry as well as the presence of sub-cooled nucleate boiling at the fuel cladding may create conditions under which a local oxidizing environment may come into existence. (orig.)

Analysis of the foreign systems for classification and marking the NPP unit components during their application in information systems

International Nuclear Information System (INIS)

Bylkin, B.K.; Shaposhnikov, V.A.; Sadovoj, Yu.K.; Tikhonovskij, V.L.; Chujko, D.V.

2006-01-01

Procedures accepted and permitted in an information system (IS) to arrange and to rank information drawn up to ensure the information support of decommissioning of an NPP power unit affect the application convenience and efficiency of the IS taken as a whole. The IS supporting the decommissioning efforts stores large volume of information, that is why, the problem to choose systems to ensure information ranking is the urgent one. The paper deals with the analysis of the foreign systems to rank the components used during an NPP operation. Besides, one considers the application of the mentioned systems to arrange and to rank the information on decommissioning of an NPP power unit presented to users [ru

Commissioning tests at Bohunice NPP V1 unit 2 after reconstruction in 1998

International Nuclear Information System (INIS)

Pajtinka, A.; Tvaroska, V.; Wiening, K.-H.; Mueller, B.

2000-01-01

The last and the most extensive stage in the reconstruction project of the Bohunice NPP started in July 1998. The main activities performed during a 6-month scheduled unit 2 outage included: - Installation of a new emergency core cooling system with an increased capacity according to the defined broader break spectrum for LOCA; - Reconstruction of the existing confinement spray system and installation of a new confinement pressure suppression system; - Completion of upgrading measures to increase the reliability of emergency power supply systems (replacement of low voltage switchgear, installation of new cabling for all loads important to safety, installation of new motor-generators and rectifier sets); - Connection to the plant and commissioning of the new reactor protection system. Comprehensive tests and checks performed on completion of installation work on the modified mechanical, electrical and I and C systems were important reasons for the absence of major problems during restart of the unit after the several project implementation phases. Operating experience at unit 2 since its recommissioning in January 1999 has confirmed that the required safety standards have been met and that operational reliability has been substantially increased at the sometime. Periodic testing is being performed in accordance with the limits and conditions for safe operation of Bohunice NPP. To date all these tests were completed without significant problems. The functions implemented in the new technology met the test program criteria, which were approved with authority, in all essential areas. Through the close cooperation of the partners involved and through the combined efforts of the various engineering and operating disciplines, technical and scheduling problems could be immediately identified and quickly resolved. In general, these kinds of projects require optimum cooperation among the parties involved. Modernization of the NPP Bohunice V1 unit 2 has shown, that all

Startup physics tests at Temelin NPP, Unit 1

International Nuclear Information System (INIS)

Sedlacek, M.; Minarcin, M.; Toth, L.; Elko, M.; Hascik, R.

2002-01-01

The objective, scope and proceedings of the physics tests of Temelin NPP, Unit 1 physical commissioning are given in this paper. Furthermore, some results of selected physics tests are presented: reactor initial criticality test, determination of reactor power range for physics testing, measurement of control rod cluster assembly group no. 10 reactivity worth in case of limitation system LS(a) actuation, control rod cluster assembly system reactivity worth measurement with single rod cluster assembly of greatest reactivity worth stuck in fully withdrawn position, measurement of differential reactivity worth of control rod cluster assembly group no. 9, boron 'endpoint' determination and measurement of power reactivity coefficient (Authors)

Experimental determinations of the turbine condenser operation at Cernavoda NPP Unit 1

International Nuclear Information System (INIS)

Romascu, Gabriel; Dragusin, Dumitru; Rogociu, Ioan; Macodean, Luminita; Marciulescu, George

1999-01-01

The condenser system represents one of the most important BOP (balance of plant) systems of the CANDU 700 MW Unit at Cernavoda NPP. The paper presents theoretical calculation elements, mathematical model for simulation of condenser operation and the results obtained by model implementation as compared to operation data. The model could be adapted to other turbine and operation regime types. (authors)

National Report of Bulgaria [National practice at WWER sites

International Nuclear Information System (INIS)

2017-01-01

Kozloduy NPP Plc. is located in north-western Bulgaria at about 3 km from the Danube River, which serves as a source of cooling water and a receiver of liquid released from the plant (Fig. I.3). Six nuclear units were constructed on Kozloduy NPP site. Units 1 to 4 are WWER-440/230 reactors and Units 5 and 6 are WWER-1000/320 reactors. Units 1 to 4 were commissioned from 1974 to 1982. Units 5 and 6 were commissioned in 1987 and 1991, respectively. On December 31, 2002 Units 1 and 2 were shut down and on December 31, 2006 Units 3 and 4 were shut down as well. Spent Nuclear Fuel was removed from the pre-reactor pools and the reactors have been prepared for decommissioning. Units 1 and 2 (in 2008) and Units 3 and 4 (in 2012) were declared as Decommissioning Facilities by Ministerial Decree and outsourced from the plant. A separate complex consisting of facilities for treatment and conditioning of wet and dry solid radioactive waste (RAW) and a facility for storage of conditioned RAW was commissioned in 2001 on site. The complex is situated next to the Auxiliary Building of Units 5 and 6. In 2005 this complex was outsourced as a separate enterprise called the Specialized Enterprise for Radioactive Waste (SE RAW). There are two Spent Fuel Storage Facilities (SFSF) for wet and dry storage located on the plant site as well.

Construction of the jet-vortex condenser at the Kozloduy NPP units 3 and 4

International Nuclear Information System (INIS)

Genovski, I.; Bonev, B.; Grigorov, A.; Sabinov, S.; Petlov, M.

2003-01-01

The paper present the behavior of the accident localization system in case of pipeline rupture in the primary circuit of the units 3 and 4 after the implementation of the modernization program. The program includes installation of a jet-vortex condenser. The cases with double rapture of a pipeline D y 200 mm and D y 500 mm are described. In the result of the program implementation the radiation consequences are significantly limited due to the condenser playing the role of a filter during the first second of the accident as well as due to the low values of the pressure during the whole accident. Thus the modernization program fulfills its purpose to assure non-exceeding of the radiation limits in case of double rupture of a main circulation pipeline

Estimation of embrittlement damage risk at neutron embrittled vessel constructions

International Nuclear Information System (INIS)

Staevski, K.; Madzharov, D.; Detistov, P.; Petrova, T.

1998-01-01

In this work a methodology based on Damage mechanics criteria is proposed. This methodology serves for probability assessment of the brittle damage risk for the neutron embrittled vessel elements. The developed methodology is realised in RISK code and has been verified on the base of tough reliability of the pressure vessel, 'Kozloduy' NPP Unit 2. This investigation has been carried out at the given parameters of the possible defects on the vessel's weld 4 taking into account requirements of the western and Russian standards. The obtained values for ductile to brittle transition temperatures, defining the equipment life-time in the presence of maximal defect, are in good consistence with the experimentally determined ones. The analyses of results show that the pressure vessel of 'Kozloduy' NPP Unit 2 has got a high level of reliability from brittle damage risk point of view and that the western standards give more conservative evaluation. On the bases of the results a conclusion is made that the developed methodology enables analysing the influence of possible defects in the neutron embrittled elements on their to reliability and their remained life-time

Diversity of microflora at the fourth destroyed unit of the ChNPP

International Nuclear Information System (INIS)

Parenyuk, O.Yu.; Shavanova, K.Je.; Yilljenko, V.V.; Gudkov, Yi.M.; Nanba, K.; Takasi, T.; Syimutyin, Yi.O.; Samofalova, D.O.; Ribalka, V.B.

2017-01-01

DNA of the substrate, sampled from six points in the destroyed 4-th power unit of ChNPP, where the dose rate on the microorganisms ranges from 0.008 to 0.12 Gy/h, was analyzed by New Generation Sequencing technology. It was found that the most diverse and stable microbiome occurs in sample, located outside of the ''Ukryttya'' object on the industrial site (conditional control). There are no dominants in it, which means that it is the most balanced and approximate to the general state of the soil microbiome of ecosystems surrounding the ChNPP. As for the sample, taken from the spot, where the dose rate was the highest, total number of species represented appeared eight times smaller, but dominance index was the highest, which indicates the formation of distinct microbiome dominants.

Preparation phase of Mochovce NPP unit 3 and 4 construction completion

International Nuclear Information System (INIS)

Cillik, I.; Tvaroska, V.; Liska, P.; Ziman, V.

2005-01-01

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.

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

International Nuclear Information System (INIS)

Hammar, K.

1998-01-01

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

Modernization of Kozloduy nuclear plant unit 5 and 6, implementation of measures to improve the reliability of the main generator system

International Nuclear Information System (INIS)

Stinshoff, H.

2003-01-01

To improve the reliability of Kozloduy Nuclear power plant several modernization measures will be implemented during the outages in the years 2003 to 2005. In the area of the main generator the following measures will be performed in unit 6 during 2003 outage: - Replacement of main generator circuit breaker by new SF6 cooled breaker type - Replacement of main generator excitation system by new two channel digital system - Replacement of main generator protection by new digital multi-purpose protections including digital fault recorders - Installation of radio frequency monitoring system of main generator circuit Starting from the present situation the new concept is explained. The project organization under consideration of large Bulgarian participation as well as the sequence and schedule of the implementation during the short outage time window is shown. These modernization measures lead to an increase of reliability and availability for the operation of the power plant and with this to increase power plant safety

Results and development prospects for the Cernavoda NPP

International Nuclear Information System (INIS)

Rotaru, Ioan

2001-01-01

The new competitive market in the power sector offers favorable conditions for continual developing of Nuclear Power in Romania. The principal arguments in this respect are: the CANDU technology is a western technology recognized world wide both for its operation reliability and its economical performances. The results obtained by Cernavoda NPP Unit 1 over a period of four years and a half commercial operation confirms the validity of the CANDU project in Romania in the new conditions of competitive market. Accomplishing the Unit 2 of Cernavoda NPP represents for the time being one of the most cost-effective investment in the Romanian power sector. Also, the participation of the local industry to the project implementation is important as it ensures the initial heavy water and nuclear fuel charging, specific materials and equipment production, design and construction works, etc. Heaving in view all these favorable arguments, the construction of Unit 2 of Cernavoda NPP represents one of the highest priorities of the State Budget of the present administration in year 2001. The Nuclear Power Project in Romania, based on CANDU technology meets national as well as EU regulations concerning nuclear power and as such its development poses no significant problems both in the context of EU extension and in the frame of the developing competitive market in the power sector. For SNN SA the main objectives in view for the next stage are: operating Cernavoda NPP Unit 1 in conditions of highest nuclear safety and economical efficiency; finalizing the Cernavoda NPP Unit 2 and creation of an organisation for operating the two units; promoting of a functional system characteristic to the competitive market economy and open to privatization; creating opportunities for exporting electrical energy. The contribution contains the following sections: 1. General overlook; 2. Performance of the power production in the year 2000; 2.1. Unit 1 of Cernavoda NPP; 2.2. Nuclear Fuel Plant

Qualification of ISI for Bulgarian NPP: UK support

International Nuclear Information System (INIS)

Booler, R.

2000-01-01

UK Regulator (NII) Phare project provides an assistance to the Bulgarian Regulator in setting up the technical infrastructure for inspection qualification consistent with IAEA Guidelines and western European practice. The Strategy Document defines the methodology for inspection qualification and general roles and responsibilities of the involved organizations. The Qualification Inputs Document describes the information required for the Technical Specifications (component details, inspection aims and limitations). It applies the idea of qualification level - level 1(lowest) to level 3 (highest). The Qualification Procedure Document provides a guidance to the utility ('Kozloduy' NPP) on the preparation of Qualification Procedures (QP). The appendix provides a specific guidance on the performance of the all aspects of qualification at different levels and recommendations for technical justification. QB Method Working Document provides guidance for the Qualification Body. Facilities and Resources Document defines the facilities and resources required for the Qualification Body to perform the tasks described in the Method Working Document. High level QA Document defines the principles of quality control. Other issues and progress report are also presented

Leningrad NPP and energetics of north-western Russia

International Nuclear Information System (INIS)

Belov, I.

2000-01-01

Problems of Leningrad NPP operating units modernization, their design service life finishing by year of 2010, are discussed. To assure safe operation of unit 1 investments in the amount of 30 mln. dol are necessary. Estimations suggest economic efficiency of the measures, permitting saving of 300 mln. dol worth of gas. Unfortunately, without a rise in tariff for electric power produced by NPP it seems impossible. It is recommended that substantiated tariffs are set for electric power produced by NPP starting from January, 2000. The measure is indispensable for raising investment funds intended for operating NPP modernization [ru

The Bohunice NPP V-1 units nuclear safety upgrading

International Nuclear Information System (INIS)

Mlcuch, M.

2000-01-01

Safety upgrading and operational reliability improvement was carried out by the Bohunice NPP V-1 staff continuously since the plant commissioning. By now, more than 1200 minor or major modifications have been implemented, either by the NPP maintenance staff or by the contractors. Based on findings of safety assessment missions invited by Bohunice NPP in 1990 - 1991, the Czecho-slovak Nuclear Regulatory Authority (CSKAE) issued the decision No. 5/91 of 81 safety upgrading measures to be taken in different areas. These improvements are referred to as the 'Small Reconstruction of the Bohunice V-1 NPP'. Realization of measures during Small reconstruction of the Bohunice NPP V-1 became a power plant, which further operation is acceptable from safety point of view, but it is also necessary further safety improvement. During the period of the Small Reconstruction the development of a Safety Report for the Gradual reconstruction has been completed. Based on this report the SR Nuclear Regulatory Authority issued the Decision No. 1/94, in which requires 59 upgrading measures in different areas to be addressed. The development of Basic Engineering of the Gradual Reconstruction has been contracted to the Siemens AG. Implementation of safety measures are provided through contract with the consortium REKON (which consists of Siemens AG company and Nuclear Power Plants Research Institute Trnava) and other Czech, Russian and Slovak companies. The Gradual Reconstruction of Bohunice NPP V-1 will be finished in 2000. By implementation of the measures carried out during Gradual Reconstruction achievement of an internationally acceptable nuclear safety level will be reached. (author)

Assessment of the residual lifetime of the units 3 and 4 of the Kozloduy NPP

International Nuclear Information System (INIS)

Mojkinski, G.

2011-01-01

The purpose of the report is to present the methodology for the residual lifetime assessment for the buildings and facilities during the decommissioning. An analysis of the existing facilities and constructions is made and requirements for further exploitation are set. A quantitative assessment is made of the residual lifetime for the buildings and auxiliary objects for the units 3 and 4. A detailed analysis is made for the ventilation systems and other equipment. Recommendations are given for the extension of the equipment lifetime

Experience of Bohunice V-1 NPP

International Nuclear Information System (INIS)

Dobik, Dobroslav

2000-01-01

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 CO x , 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

Analytical validation of operator actions in case of primary to secondary leakage for VVER-1000/V320

Energy Technology Data Exchange (ETDEWEB)

Andreeva, M., E-mail: m_andreeva@inrne.bas.bg; Groudev, P., E-mail: pavlinpg@inrne.bas.bg; Pavlova, M., E-mail: pavlova@inrne.bas.bg

2015-12-15

Highlights: • We validate operator actions in case of primary to secondary leakage. • We perform four scenarios related to SGTR accident for VVER-1000/V320. • The reference power plant for the analyses is Unit 6 at Kozloduy NPP. • The RELAP5/MOD 3.2 computer code is used in performing the analyses. • The analyses confirm the effectiveness of operator actions during PRISE. - Abstract: This paper presents the results of analytical validation of operator actions in case of “Steam Generator Tube Rupture” (SGTR) for VVER-1000/V320 units at Kozloduy Nuclear Power Plant (KNPP), done during the development of Symptom Based Emergency Operating Procedures (SB EOPs) for this plant. The purpose of the analyses is to demonstrate the ability to terminate primary to secondary leakage and to indicate an effective strategy for preventing secondary leakage to the environment and in this way to prevent radiological release to the environment. Following depressurization and cooldown of reactor coolant system (RCS) with isolation of the affected steam generator (SG), in these analyses are validated options for post-SGTR cooldown by: • back up filling the ruptured SG; • using letdown system in the affected SG and • by opening Fast Acting Isolation Valve (FAIV) and using Steam Dump Facility to the Condenser (BRU-K). The results of the thermal-hydraulic analyses have been used to assist KNPP specialists in analytical validation of EOPs. The RELAP5/MOD3.2 computer code has been used for the analyses in a VVER-1000 Nuclear Power Plant (NPP) model. A model of VVER-1000 based on Unit 6 of Kozloduy NPP has been developed for the thermal-hydraulics code RELAP5/MOD3.2 at the Institute for Nuclear Research and Nuclear Energy – Bulgarian Academy of Sciences (INRNE-BAS). This paper is possible through the participation of leading specialists from KNPP.

Principles of tariff determination for NPP electric power generation

International Nuclear Information System (INIS)

Ratnikov, B.E.; Gitel'man, L.D.; Artemov, Yu.N.; Fiantsev, V.S.

1988-01-01

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

Current status of Chernobyl NPP decommissioning

International Nuclear Information System (INIS)

2009-01-01

Strategy of Chernobyl NPP decommissioning with the decommissioning license 2002-2064 is presented. The main activities at the stage of ChNPP units shutdown (2002 - 2012) are: units maintenance in safe state; decommissioning infrastructure construction; unloading of SNF – main activity determining the stage duration; systems and elements final shutdown; decommissioning life-support systems reconstruction; Comprehensive engineering and radiation survey (CERS); dismantling of the reactor facilities external equipment; removal of RAW from units; decommissioning documentation development. The decommissioning activities main results are presented

Irradiation Embrittlement Monitoring Programs of RPV's in the Slovak Republic NPP's

International Nuclear Information System (INIS)

Kupca, Ludovik

2006-01-01

Four types of surveillance programs were (are) realized in Slovak NPP's: 'Standard Surveillance Specimen Program' (SSSP) was finished in Jaslovske Bohunice V-2 Nuclear Power Plant (NPP) Units 3 and 4, 'Extended Surveillance Specimen Program' (ESSP), was prepared for Jaslovske Bohunice NPP V-2 with aim to validate the SSSP results, For the Mochovce NPP Unit 1 and 2 was prepared completely new surveillance program 'Modern Surveillance Specimen Program' (MSSP), based on the philosophy that the results of MSSP must be available during all NPP service life, For the Bohunice V-1 NPP was finished 'New Surveillance Specimen Program' (NSSP) coordinated by IAEA, which gave arguments for prolongation of service life these units for minimum 20 years, New Advanced Surveillance Specimen Program (ASSP) for Bohunice V-2 NPP (units 3 and 4) and Mochovce NPP (units 1, 2) is approved now. ASSP is dealing with the irradiation embrittlement of heat affected zone (HAZ) and RPV's austenitic cladding, which were not evaluated till this time in surveillance programs. SSSP started in 1979 and was finished in 1990. ESSP program started in 1995 and will be finished in 2007, was prepared with aim of: increasing of neutron fluence measurement accuracy, substantial improvement the irradiation temperature measurement, fixed orientation of samples to the centre of the reactor core, minimum differences of neutron dose for all the Charpy-V notch and COD specimens, the dose rate effect evaluation. In the year 1996 was started the new surveillance specimen program for the Mochovce RPV's unit-1 and 2, based on the fundamental postulate - to provide the irradiation embrittlement monitoring till the end of units operation. The 'New Surveillance Specimen Program' (NSSP) prepared in the year 1999 for the Bohunice V-1 NPP was finished in the year 2004. Main goal of this program was to evaluate the weld material properties degradation due to the irradiation and recovery efficiency by annealing too. The

The seismic reassessment Mochovce NPP

International Nuclear Information System (INIS)

Baumeister, P.

2004-01-01

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)

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

International Nuclear Information System (INIS)

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

2015-01-01

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)

Preparation for Ignalina NPP decommissioning

International Nuclear Information System (INIS)

Medeliene, D.

2004-01-01

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

Electromagnetic compatibility of tools and automated process control systems of NPP units

International Nuclear Information System (INIS)

Alpeev, A.S.

1994-01-01

Problems of electromagnetic compatibility of automated process control subsystems in NPP units are discussed. It is emphasized, that at the stage of development of request for proposal for each APC subsystem special attention should be paid to electromagnetic situation in specific room and requirements to the quality of functions performed by the system. Besides, requirements to electromagnetic compatibility tests at the work stations should be formulated, and mock-ups of the subsystems should be tested

Modernization and safety improvement project of the NPP V-2 Jaslovske Bohunice

International Nuclear Information System (INIS)

Michal, V.; Losonsky, B.; Magdolen, J.

2000-01-01

This contribution deals with the form, present state, and results of the Nuclear Power Plants Research Institute (the Slovak acronym is VUJE - Vyskumny Ustav Jadrovych Elektrarni) participation in the NPP V-2 Jaslovske Bohunice Modernization and Safety Improvement Project. A short description of VUJE history, activity, and results is also presented as well as NPPs Jaslovske Bohunice characterization. VUJE was established in 1977 and deals with scientific and research needs of nuclear power plants, such as design, construction, commissioning and operation. The next fields of VUJE activity are, NPP reconstruction, NPP personnel training, radioactive waste management technology, and NPP decommissioning. The nuclear power plant, Jaslovske Bohunice, is situated approximately 15 km from the district town of Trnava in the southwestern region of the Slovak Republic. The construction of the first Czechoslovak NPP A-1 began on this site in 1957 .The construction of the double-unit NPP V-1 with WWER-440 (type V-230) reactor began in 1972. The first unit of NPP V-1 began operation in 1978 and the second in 1980. NPPs construction on the Bohunice site continued with NPP V-2, which has two units with WWER-440 (type V-213) reactors. Unit 1 and Unit 2 of NPP V-2 were commissioned in 1984 and 1985, respectively. Slovak electric utility Slovenske elektrarne (SE) is the owner/commissioner of NPP V-2. This NPP is responsible for more than 20% of the total electrical energy production of SE, making it an essential supporter of the Slovak economy. (authors)

Integrated ageing management of Atucha NPP

International Nuclear Information System (INIS)

Ranalli, Juan M.; Marchena, Martin H.; Zorrilla, Jorge R.; Antonaccio, Elvio E.; Brenna, Pablo; Yllanez, Daniela; Cruz, Gerardo Vera de la; Luraschi, Carlos; Sabransky, Mario

2013-01-01

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)

Integrated Ageing Management of Atucha NPP

International Nuclear Information System (INIS)

Ranalli, J.M.; Marchena, M.H.; Zorrilla, J.R.; Sabransky, M.

2012-01-01

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)

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)

Analysis of design floor response spectra and testing of the electrical systems

International Nuclear Information System (INIS)

Ambriashvili, Y.

1996-01-01

This report covers the following activities as foreseen according to the working plan of 'Atmoenergoproject': analysis of calculated floor response spectra used during the design of Kozloduy NPP and comparison with other spectra recommended for this NPP; analysis of floor response spectrum for the most important systems (reactor, main coolant loop, electrical systems); tests of main electrical systems and analysis of the results on seismic stability of those systems. Results of the response spectra analysis are given, some of the electrical systems are identified by the Kozloduy authorities to be analyzed in future according to the results of the test on seismicity

Chernobyl NPP decommissioning efforts - Past, Present and Future. Decommissioning Efforts on Chernobyl NPP site - Past, Present

International Nuclear Information System (INIS)

Kuchinskiy, V.

2017-01-01

Two unique large-scale projects are underway at the moment within the Chernobyl - Exclusion zone - Shelter object transformation into ecologically safe system and the decommissioning of 3 Chernobyl NPP Units. As a result of beyond design accident in 1986 the entire territory of the industrial site and facilities located on it was heavily contaminated. Priority measures were carried out at the damaged Unit under very difficult conditions to reduce the accident consequences and works to ensure nuclear and radiation safety are continuous, and the Unit four in 1986 was transformed into the Shelter object. Currently, works at the Shelter object are in progress. Under assistance of the International Community new protective construction was built above the existing Shelter object - New Safe Confinement, which will ensure the SO Safety for the long term - within up to 100 years. The second major project is the simultaneous decommissioning of Chernobyl NPP Units 1, 2 and 3. Currently existing Chernobyl NPP decommissioning Strategy has been continuously improved starting from the Concept of 1992. Over the years the following was analyzed and taken into account: the results of numerous research and development works, international experience in decommissioning, IAEA recommendations, comments and suggestions from the governmental and regulatory bodies in the fields of nuclear energy use and radioactive waste management. In 2008 the final decommissioning strategy option for Chernobyl NPP was approved, that was deferred gradual dismantling (SAFSTOR). In accordance with this strategy, decommissioning will be carried out in 3 stages (Final Shutdown and Preservation, Safe Enclosure, Dismantling). The SAFSTOR strategy stipulates: -) the preservation of the reactor, the primary circuit and the reactor compartment equipment; -) the dismantling of the equipment external in relation to the reactor; -) the safe enclosure (under the supervision); -) the gradual dismantling of the primary

Two managerial grids in NPP

International Nuclear Information System (INIS)

Zhao Hui

2012-01-01

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)

Numerical Analysis of Loss of Residual Heal Removal System (RHRS) during Mid-Loop Operation for Hanul NPP Units 1 and 2

Energy Technology Data Exchange (ETDEWEB)

Kim, Sook Kwan; Park, Seong Gyu; Han, Sang Koo [ACT Co., Daejeon (Korea, Republic of)

2016-10-15

As a part of supporting LPSD (Low Power and Shutdown) PSA (Probabilistic Safety Assessment) of Hanul NPP units 1 and 2, numerical analysis for a loss of RHRS (Residual Heat Removal system) during midloop operation was performed using RELAP5/MOD3.3 code. The one of main purpose of thermal hydraulic analysis for PSA work is to estimate times allowable for operation actions in each accident. A loss of RHRS during mid-loop operation may cause more significant results than during RCS full condition due to reduced RCS inventory. In order to perform this kind of analysis, it is particularly important to establish a steady state of mid-loop operational initial condition. Mid-loop operation corresponds to POS(Plant Operational State) 5 and 11 in the category of LPSD PSA at Hanul NPP units 1 and 2. RELAP5/MOD3.3 code was used to predict behaviors of RCS and fuels for the case of loss of RHRS during mid-loop operation at Hanul NPP units 1 and 2. The initial state of mid-loop operational condition was established by proper control of charging and letdown flow. Considering existing similar analysis results for this kind of accident, it can be concluded that RELAP5 code well predicts reasonably the behavior of RCS for loss of RHRS during mid-loop operation in Hanul NPP units 1 and 2. Thus the method developed in the analysis can be applied reasonably to support LPSD PSA.

Kozloduy nuclear power plant. Units 1-4. Status of safety improvements. Rev. 2

International Nuclear Information System (INIS)

1999-01-01

This paper presents the results of the safety improvements activities carried out by the Kozloduy Nuclear Power Plant (KNPP) within the period 1990-1998. The steam supply system of this units is based of the reactor WWER-440/ B-230, which is a PWR of russian design developed according to the safety standards in force in USSR in late sixties. Up to now 10 reactor units of this type are in operation in four NPPs. Despite of efforts of the different plants to implement safety improvements measures during first 10-15 years of operation of this type of reactor its major safety problems were not eliminated and were a subject of international concern. The systematic evaluation of the deficiencies of the original design of this type of reactors have been initiated by IAEA in the beginning of 1990 and brought to developing a comprehensive list of safety problems which required urgent implementation of safety measures in all plants. To solve this problems in 1991 KNPP initiated implementation of so called 'short term' safety improvement program, developed with the help of WANO under agreement with Bulgarian Nuclear Safety Authority (BNSA) and consortium RISKAUDIT. The program was based on a stage approach and was foreseen to be implemented by tree stages in very tight time schedule in order to achieve significant and rapid improvements of the level of safety in operation of the units. The Short term program was implemented between from 1991 to 1997 owing to strong safety commitment of NEC and KNPP staff as well as broad international cooperation and financial support. Important part of resources were supplied under PHARE program of CEC, EBRD grant agreement and EDF support. In parallel a special assessment process started in 1995 in order to evaluate the level of safety, achieved by Short Term Program, according to current safety standards and to define the measures, which should be implemented by the Utility to complete the process of improving the safety in future

Radiobiological significance of radioactive contamination - summary assessment based on great number of measurements

International Nuclear Information System (INIS)

Angelov, V.; Bonchev, Ts.; Mavrodiev, V.; Kyrdzhilov, N.

1995-01-01

In order to facilitate quantitative and qualitative characterisation of radioactive contamination the authors introduce a relative estimate of radionuclide activity by setting as a reference the most abundant element -Co-60 in the case of the Kozloduy NPP. The ratio η i of the mean annual permissible concentration in air for each radionuclide (RPC-92) to that of Co-60 is calculated. It is found that η i has the same or close values for groups of radionuclides, e.g. η i = 2.10 -4 for 238 Pu, 239 Pu, 240 Pu, 241 Am, 244 Cm; η i = 5 for 89 Sr, 91 Y; 93 Nb, 134 Cs, 137 Cs; η i = 50 for 55 Fe, 63 Ni, 95 Zr, 95 Nb, 140 Ba, 140 La. Then it is compared to the experimentally measured values of the same quantity η iexp , derived from surface contamination data. The ratio η iexp /η i is plotted against log η i . The resulting nomograms give graphic representation of the radiobiological significance of various radionuclide groups. Data from different locations at the Kozloduy NPP are presented. It is found that the alpha emitter contamination has highest values in the Unit 1 (WWER-440) control rooms after repair. The Unit 5 (WWER-1000) has lower alpha contamination compared to WWER-440 units. 1 ref., 5 figs., 1 tab

Adjustment of the Kompleks Titan-2 monitoring computerized system at the Rovno NPP third unit

International Nuclear Information System (INIS)

Zigaev, B.P.

1987-01-01

Information signal origin and processing processes in the monitoring computerized system 'Komplex Titan-2' at the Rovno NPP third unit are considered. The system exercises control over the following production equipment parameters: the state of keys of control of lock fittings, mechanisms, regulators, reserve mechanism automatic shut-down circuit; the state of lock fittings, mechanisms, regulators, reserve mechanism automated switching on; parameter deviation from permissible values; interlock operation; protection system state; the state of autonomous units and devices

New approach of second Romanian NPP siting

International Nuclear Information System (INIS)

Mauna, Traian

2010-01-01

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)

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.

Role of the team of scientific and technical commissioning support (TSTCS) during Mochovce NPP unit 3 and 4 commissioning

International Nuclear Information System (INIS)

Hermansky, J.; Prachar, M.; Sedlacek, M.; Petenyi, V.

2011-01-01

The Team of Scientific and Technical Commissioning Support (TSTCS) shall provide an independent support for the Mochovce NPP 3 and 4 Commissioning Department during Mochovce Units 3 and 4 commissioning. This independent support will be in line with the Mochovce NPP 3 and 4 Directive 'Non-active tests and commissioning' and it will be carried out in form of professional and expert works focusing on supervision of fulfilment of requirements for nuclear safety observance. The TSTCS duty to provide for such services during NPP commissioning is specified by Slovak Regulatory Body legislation. The independent TSTCS will supervise; - fulfilment of requirements for nuclear safety during preparation and implementation of commissioning tests; -scientific and technical level of commissioning programmes, and reflection on nuclear safety requirements in commissioning programmes,- commissioning process and test results. Main standpoints of the Team activities for individual unit commissioning stages will be; - assesment of the selected programs of functional tests in installations having an impact on nuclear safety and evaluation of the results of these tests; - assesment of the programs of physics and power commissioning, - assesment of the unit preparedness before fuel loading start; - assesment of the unit preparedness for performing initial criticality and low power commissioning and power commissioning stages; - evaluation of the results of physics and power commissioning stages and sub-stages; - final evaluation of the results from implementing the physics and power commissioning stages. The paper also presents a short description of the Team scope activities, the Team organisation, and a procedure for issuing of standpoints to individual unit commissioning stages. (Authors)

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

International Nuclear Information System (INIS)

Tzocheva, V.

2012-01-01

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

Russian normative approach to the question of management of NPP life time

International Nuclear Information System (INIS)

Karpunin, N.I.

2002-01-01

Full text: In Russia, the designated service life of a nuclear power plant (NPP) is 30 years. During the period 2001-2010, 15 Russian NPP units will reach the end of their service life. The 'Basic Provisions of NPP Safety Assurance', OPB-88/97, Item 5.1.14, provide for a possible extension of NPP operation beyond the designated service life. For such an extension, the NPP operating organization must apply for a license renewal to Gosatomnadzor, which needs to specify the relevant requirements. GAN is developing regulatory documents to provide a basis for NPP license renewal/extension of NPP operation, which would benefit from international experience. In accordance with 'The program of Atomic Energy Development in the Russian Federation for 1998-2005 and up to 2010' adopted by Decree No. 815 of the Government of the Russian Federation on 21 July 1998, priority is placed on the preparation of NPPs for extension of service life and on ensuring safety in the extended operating period. The length of the extension beyond the designated service life is to be determined on the basis of a range of technical and economic considerations, including: The ability to ensure and maintain operational safety; Sufficient residual service life of the unit's non-repairable components; The availability of temporary storage facilities for the additional spent nuclear fuel and radioactive waste, or the possibility of its transport off-site; The ability to ensure safe handling of the radioactive waste generated during the extension period; To extend the lifetime of an NPP unit, the plant Operator is required to perform the following tasks: Carry out a comprehensive survey of the NPP unit; Draw up a programme of preparation for lifetime extension; Prepare the NPP unit for operation in the extended period; Carry out the necessary tests. There are also some normative documents, which regulate management of NPP life time. (author)

Structural capacity assessment of WWER-1000 MW reactor containment. Progress report

International Nuclear Information System (INIS)

Jordanov, M.

1999-01-01

The objective of the project is to provide assessment of the structural behaviour and safety capacity of the WWER-1000 MW Reactor Building Containment at Kozloduy NPP under critical combination of loads according to the current international requirements. The analysis is focused on a realistic assessment of the Containment taking into account the non-linear shell behaviour of the pre-stressed reinforced concrete structure. Previous assessments of the status of pre stressing cables pointed out that the efficiency of the Containment as a final defence barrier for internal and external events depends on their reliability. Due to this, the experimental data obtained from embedded sensors (gauges) at pre-stressed shell structure is to be compared with the results from analytical investigations. The reliability of the WWER-1000 MW accident prevention system is under evaluation in the project. The Soviet standard design WWER-1000 MW type units installed in Kozloduy NPP were originally designed for a Safe Shutdown Earthquake (SSE) with a peak ground acceleration (PGA) of 0.1g. The new site seismicity studies revealed that the seismic hazard for the site significantly exceeds the originally estimated and a Review Level Earthquake (RLE) anchored to PGA=0.20g was proposed for re-assessment of the structures and equipment at Kozloduy NPP. The scope of the study is a re-assessment of the Containment structure under critical combination of loads according to the current safety and reliability requirements, including comparison between the Russian design requirements and the international regulations. Additionally, an investigation of the pre-stressing technology and the annual control of the cables' pre-stressing of the Containment is to be made. The crane influence on the dynamic behaviour of the Containment will be done as well as a study of the integrity of the Containment as a final defence barrier

Preparation of Long Term Operation in Dukovany NPP, Czech Republic

International Nuclear Information System (INIS)

Krivanek, R.; Sabata, M.

2012-01-01

Dukovany NPP in the south-east of the Czech Republic operates four VVER 440/213 type units. The first unit was commissioned in 1985 and the last one in 1987. The operational results of the whole NPP have been excellent and NPP permanently belongs between the first quartile of the best operated NPPs in the world in accordance with WANO factors. Large safety improvement programme have been implemented in last 15 years. The original design lifetime of main components is 30 years which means till 2015 and it is understandable that NPP is preparing for long-term operation (LTO). The paper is describing activities carried out and planned for safe and successful LTO. (author)

Adaption, validation and application of advanced codes with 3-dimensional neutron kinetics for accident analysis calculations - STC with Bulgaria

International Nuclear Information System (INIS)

Grundmann, U.; Kliem, S.; Mittag, S.; Rohde, U.; Seidel, A.; Panayotov, D.; Ilieva, B.

2001-08-01

In the frame of a project on scientific-technical co-operation funded by BMBF/BMWi, the program code DYN3D and the coupled code ATHLET-DYN3D have been transferred to the Institute for Nuclear Research and Nuclear Energy (INRNE) Sofia. The coupled code represents an implementation of the 3D core model DYN3D developed by FZR into the GRS thermal-hydraulics code system ATHLET. For the purpose of validation of these codes, a measurement data base about a start-up experiment obtained at the unit 6 of Kozloduy NPP (VVER-1000/V-320) has been generated. The results of performed validation calculations were compared with measurement values from the data base. A simplified model for estimation of cross flow mixing between fuel assemblies has been implemented into the program code DYN3D by Bulgarian experts. Using this cross flow model, transient processes with asymmetrical boundary conditions can be analysed more realistic. The validation of the implemented model were performed with help of comparison calculations between modified DYD3D code and thermal-hydraulics code COBRA-4I, and also on the base of the collected measurement data from Kozloduy NPP. (orig.) [de

Safety upgrading program in NPP Mochovce

International Nuclear Information System (INIS)

Baumeister, P.

1999-01-01

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)

Experience in scientific guidance during start-up and normal operation of NPPs with WWER reactors; Opyt nauchnogo rukovodstva puskom i soprovozhdeniya pri ehkspluatatsii ehnergoblokov AEhS s WWER

Energy Technology Data Exchange (ETDEWEB)

Abagyan, A; Kazakov, V; Kryakvin, L [All-Russian Inst. for NPP Operation, Moscow (Russian Federation)

1996-12-31

The experience gained in the All-Russian Research Institute of NPP Operation (RU) in improvement of reactor start-up and normal operation of NPPs has been reported. The work was carried out on NPPs in Russia, Ukraine, Bulgaria, Hungary and Czechoslovakia. All scientific programmes applied use the system approach, modern methods of safety assessment and the principle of loss effect optimization. For the Kozloduy NPP the following projects have been implemented: design of accelerated unloading system for WWER-1000; refinement of water feeding unit for the WWER-1000 steam generator; response analysis of the safety anti-breakdown system of the second loop. The importance of technical substantiation in the process of decision making is stressed. 6 refs.

Overview of Cernavoda NPP training programme

International Nuclear Information System (INIS)

Valache, Cornelia

2005-01-01

Full text: The paper presents a general assessment of Cernavoda NPP personnel training programme, highlighting the role of training in human performance improvement. Cernavoda NPP Personnel Training and Authorization Department (PTAD) is the one responsible for the training of Unit 1 and 2 staff. PTAD is structured in such a manner as to support and respond to all Cernavoda NPP 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 Programmes 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 Programmes are structured on the initial and continuing personnel training. Their content and goals respond to the training specific needs for each plant major job family. In order to successfully support NPP training programmes, 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. There are also a number of general areas for improvement of PTAD activity, such as operators and maintenance training, initial and continuing training of both Unit 1 and 2 staff. 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)

Chernobyl NPP accident. Overcoming experience. Acquired lessons

International Nuclear Information System (INIS)

Nosovskij, A.V.; Vasil'chenko, V.N.; Klyuchnikov, A.A.; Prister, B.S.

2006-01-01

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

Fuel leak testing performance at NPP Jaslovske Bohunice

International Nuclear Information System (INIS)

Slugen, V.; Krnac, S.; Smiesko, I.

1995-01-01

The NPP Bohunice VVER-440 fuel leak testing experience are relatively extensive in comparison with other VVER-440 users. As the first Europe NPP was adapted Siemens (KWU) in core-sipping equipment to VVER-440 units and since this time were have done these tests also for NPP Paks (Hungary) and NPP Dukovany (Czech Republic). The occurrence of leaking fuel assemblies in NPP is in the last 5 years relatively stabilised and low. A significant difference can be observed between type V-230 (31 leaks) and type V-213 (1 leak). None of of the indicated leaking fuel assemblies has been investigated in the hot cell. Therefore cannot be confirm the effective causes of leak occurrence. Nevertheless, the fuel failure rate and the performance of leak testing in NPP Bohunice are comparable to the world standard at PWR's. 1 tab., 2 figs., 3 refs

Fuel leak testing performance at NPP Jaslovske Bohunice

Energy Technology Data Exchange (ETDEWEB)

Slugen, V; Krnac, S [Slovak Technical Univ., Bratislava (Slovakia); Smiesko, I [Nuclear Powr Plant EBO, Jaslovske Bohuce (Slovakia)

1996-12-31

The NPP Bohunice VVER-440 fuel leak testing experience are relatively extensive in comparison with other VVER-440 users. As the first Europe NPP was adapted Siemens (KWU) in core-sipping equipment to VVER-440 units and since this time were have done these tests also for NPP Paks (Hungary) and NPP Dukovany (Czech Republic). The occurrence of leaking fuel assemblies in NPP is in the last 5 years relatively stabilised and low. A significant difference can be observed between type V-230 (31 leaks) and type V-213 (1 leak). None of of the indicated leaking fuel assemblies has been investigated in the hot cell. Therefore cannot be confirm the effective causes of leak occurrence. Nevertheless, the fuel failure rate and the performance of leak testing in NPP Bohunice are comparable to the world standard at PWR`s. 1 tab., 2 figs., 3 refs.

Novelly formed products of the interaction of fuel with construction materials of the 4th unit of Chernobyl NPP

International Nuclear Information System (INIS)

Borovoj, A.A.; Galkin, B.Ya.; Krinitsyn, A.P.; Pazukhin, Eh.M.; Kheruvimov, A.N.; Chechcherov, K.P.; Anderson, E.B.

1991-01-01

Radiation environment and map of sampling route in the steam distributing collector of the 4th unit of the Chernobyl NPP are described. The results of gamma- and alpha radiometric analyses as well as chemical analysis are presented. Samples of core materials taken from the depth of fuel-containing masses by drilling through reactor vault wall of the damaged power unit are described

Methodology and measures for preventing unacceptable flow-accelerated corrosion thinning of pipelines and equipment of NPP power generating units

Science.gov (United States)

Tomarov, G. V.; Shipkov, A. A.; Lovchev, V. N.; Gutsev, D. F.

2016-10-01

Problems of metal flow-accelerated corrosion (FAC) in the pipelines and equipment of the condensate- feeding and wet-steam paths of NPP power-generating units (PGU) are examined. Goals, objectives, and main principles of the methodology for the implementation of an integrated program of AO Concern Rosenergoatom for the prevention of unacceptable FAC thinning and for increasing operational flow-accelerated corrosion resistance of NPP EaP are worded (further the Program). A role is determined and potentialities are shown for the use of Russian software packages in the evaluation and prediction of FAC rate upon solving practical problems for the timely detection of unacceptable FAC thinning in the elements of pipelines and equipment (EaP) of the secondary circuit of NPP PGU. Information is given concerning the structure, properties, and functions of the software systems for plant personnel support in the monitoring and planning of the inservice inspection of FAC thinning elements of pipelines and equipment of the secondary circuit of NPP PGUs, which are created and implemented at some Russian NPPs equipped with VVER-1000, VVER-440, and BN-600 reactors. It is noted that one of the most important practical results of software packages for supporting NPP personnel concerning the issue of flow-accelerated corrosion consists in revealing elements under a hazard of intense local FAC thinning. Examples are given for successful practice at some Russian NPP concerning the use of software systems for supporting the personnel in early detection of secondary-circuit pipeline elements with FAC thinning close to an unacceptable level. Intermediate results of working on the Program are presented and new tasks set in 2012 as a part of the updated program are denoted. The prospects of the developed methods and tools in the scope of the Program measures at the stages of design and construction of NPP PGU are discussed. The main directions of the work on solving the problems of flow

Kozloduy nuclear power plant. Units 1-4. Status of safety assessment activities. Rev. 2

International Nuclear Information System (INIS)

1999-01-01

This paper presents the results of the status of safety assessment activities carried out by the Kozloduy Nuclear Power Plant (KNPP) in order to evaluate the current status of the safety of its reactor units 1-4. The steam supply system of this units is based of the reactor WWER-440/ B-230, which is a PWR of Russian design developed according to the safety standards in force in USSR in late 60-s. Now a days 10 reactor units of this type are in operation in four NPPs. Despite of efforts of the different plants to implement safety improvements measures during first 10-15 years of operation of this type of reactor its major safety problems were not eliminated and were a subject of international concern. The systematic evaluation of the deficiencies of the original design of this type of reactors have been initiated by IAEA in the beginning of 1990 and brought to developing a comprehensive list of safety problems which required urgent implementation of safety measures in all plants. To solve this problems in 1991 KNPP initiated implementation of so called 'short term' safety improvement program, developed with the help of WANO under agreement with Bulgarian Nuclear Safety Authority (BNSA) and consortium RISKAUDIT. The program was based on a stage approach and was foreseen to be implemented by tree stages in very tight time schedule in order to achieve significant and rapid improvements of the level of safety in operation of the units. The Short Tenn Program was implemented between the years 1991 and 1997 thanks of the strong safety commitment of NEK and KNPP staff and the broad international cooperation and financial support. Important part of resources were supplied under PHARE program of CEC, EBRD grant agreement and EDF support. The plant current safety level analysis has been performed using IAEA analytical methodology according to 50-SG-O12 standard 'Periodic safety review of operational nuclear power plants'. The approach and criteria for acceptable safety level

Project No. 10 - Partial restoration of Ignalina NPP territory

International Nuclear Information System (INIS)

2000-01-01

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

Preparation for Early Termination of Ignalina NPP Operation

International Nuclear Information System (INIS)

Poskas, P.; Poskas, R.

2003-01-01

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

Study on the power control system for NPP power unit with the WWER-440 reactor

International Nuclear Information System (INIS)

Aleksandrova, N.D.; Naumov, A.V.

1981-01-01

Results of model investigations into basic version of the power control systems (PCS) conformably to the WWER-440 NPP power unit are stated. Transient processes in the power unit system when being two PCS versions during perturbations of different parameters: unit power, vapour pressure or position of control rods have been simulated. Investigations into the different PCS versions show that quality of operation of a traditional scheme with a turbine power controller and reactor pressure controller can be significantly improved with the introduction of a high-speed signal of pressure into the reactor controller. The PCS version with the compensation of interrelations between the turbine and reactor controllers constructed according to the same principles as the standard schemes of power units of thermal electric power plant is perspective as well [ru

Sitting Safety Aspects of Second Romanian NPP

International Nuclear Information System (INIS)

Mauna, T.

2010-01-01

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

Risk management solutions for Cernavoda Unit #2 NPP completion

International Nuclear Information System (INIS)

Chirica, T.; Pall, S.

2002-01-01

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)

Operation time extension for power units of the first generation NPP and the liability for potential damage

International Nuclear Information System (INIS)

Kovalevich, O.M.

2000-01-01

The problem on the operation time extension for the six operating NPP first generation power units is discussed. However it is not advisable to improve the safety of these power units up to the acceptable level, therefore there arises the contradiction between the operation time extension of these power units and potential damage for the population. The possibility of having the increased civilian-legal responsibility for potential harm and losses in case of an accident is proposed to be considered as a compensating measure. The measures for realization of this civilian-legal responsibility are described [ru

Dukovany NPP - Safely 16 TERA

International Nuclear Information System (INIS)

Vlcek, J.

2008-01-01

In this presentation increasing of power output of the Dukovany NPP is reviewed. To operate all Dukovany Units safely with the perspective of long-term operation (LTO) of 50 - 60 years it is proposed.

Cytochalasin-b micronucleus test of peripheral blood lymphocytes of Kozloduy NPP workers

International Nuclear Information System (INIS)

Hadjidekova, V.; Hristova, R.; Atanassova, P.; Stainova, A.; Popova, L.

2006-01-01

Full text: The cytokinesis-block micronucleus assay in peripheral blood lymphocytes was applied to evaluate occupational radiation exposure of 65 nuclear power plant workers. Blood samples were collected from 43 workers aged between 32-54 years, mean age 41,7 years. The accumulated radiation doses for each subject varied between 7,9 - 766,4 mSv, mean level of the whole group is 237,78 mSv. Controls were 22 healthy individuals, (13 male and 9 female), aged between 27-52 years, mean age 38,8 years, selected from the administrative staff. All subjects participating in this study were interviewed concerning health status, professional history, smoking habit and other aspects relevant to the study. At least 1000 binucleated cells were analysed per person. The detected frequencies of micronuclei in the control group were ranged between 4.0 and 23.5 per 1000 binucleated cells, with the average incidence yield of 12.16 ±5.59 %. The mean group value of the frequency of micronuclei in peripheral lymphocytes of exposed workers was found to be 18.46±6.72 % in 1000 cells. The difference between the mean frequency of micronuclei in the group of exposed subjects and the control group was statistically significant (P<0,001). The correlation coefficient for duration of employment and accumulated doses is 0,30 (P<0,05). After 1,5 Gy in vitro irradiation of peripheral blood from investigated workers and controls a decreased radiosensitivity of NPP workers is detected using micronucleus assay. Decreased radiosensitivity of the professionally exposed workers could be due to the phenomenon of adaptive response. Micronucleus assay in peripheral blood lymphocytes is useful approach in cytogenetic monitoring of occupationally exposed nuclear industry workers

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

International Nuclear Information System (INIS)

Cillik, I.

1997-01-01

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)

Determination of reactor parameters during start up test at the Taiwan NPP, Unit 1

International Nuclear Information System (INIS)

Astakhov, S.; Kravchenko, A.; Kraynov, Ju.; Nasedkin, A.; Tsyganov, S.

2006-01-01

Unit 1 of Taiwan NPP with WWER-1000 reactor reached the first criticality at December 20 of 2005. Series of start up experiments were carried out under scientific advisory of RRC 'Kurchatov Institute' specialists. At the Hot Zero Power state the reactivity coefficients, control rod group and scram worth were measured and symmetry of the core loading and power reactivity effect due to reaching 1% of nominal were assessed. Paper describes in brief special features of experiments and presented some results obtained at a measurements (Authors)

Experimental investigations and seismic analyses for benchmark study of 1000 MW WWER type (water-cooled and moderated reactor) nuclear power plant Kozloduy. Final report 15 June 1993 - 14 June 1994

Energy Technology Data Exchange (ETDEWEB)

Sachansky, S [Building Research Institute (NISI), Sofia (Bulgaria)

1995-07-01

This report includes preparation and compilation of all existing studies related to seismic safety assessment of Kozloduy WWER-1000, i.e. Units 5 and 6; description of previous full scale testing of Unit 5; and the results obtained from seismic analyses performed under benchmark experimental studies. The results are concerned with analysis of the geological conditions; analysis of the seismic wave velocities in the soil layers; analysis of the predominant natural periods; dynamic characteristics of the Unit 5; soil-structure interaction and laboratory testing and analysis of the reactor containment tenders.

Experimental investigations and seismic analyses for benchmark study of 1000 MW WWER type (water-cooled and moderated reactor) nuclear power plant Kozloduy. Final report 15 June 1993 - 14 June 1994

International Nuclear Information System (INIS)

Sachansky, S.

1995-01-01

This report includes preparation and compilation of all existing studies related to seismic safety assessment of Kozloduy WWER-1000, i.e. Units 5 and 6; description of previous full scale testing of Unit 5; and the results obtained from seismic analyses performed under benchmark experimental studies. The results are concerned with analysis of the geological conditions; analysis of the seismic wave velocities in the soil layers; analysis of the predominant natural periods; dynamic characteristics of the Unit 5; soil-structure interaction and laboratory testing and analysis of the reactor containment tenders

NPP construction cost in Canada

International Nuclear Information System (INIS)

Gorshkov, A.L.

1988-01-01

The structure of capital costs during NPP construction in Canada is considered. Capital costs comprise direct costs (cost of the ground and ground rights, infrastructure, reactor equipment, turbogenerators, electrotechnical equipment, auxiliary equipment), indirect costs (construction equipment and services, engineering works and management services, insurance payments, freight, training, operating expenditures), capital per cents for the period of construction and cost of heavy water storages. It proceeds from the analysis of the construction cost structure for a NPP with the CANDU reactor of unit power of 515, 740 and 880 MW, that direct costs make up on the average 62%

The design preparation for radiation monitoring system in the frame of completion NPP Mochovce Units 3 and 4

International Nuclear Information System (INIS)

Sevecka, S.; Slavik, O.; Kapisovsky, V.

2009-01-01

In 1985 a Basic Design of Radiation Monitoring System (RMS) has been elaborated for Mochovce NPP unit 3 and 4 construction. Due to construction interruption in the following years this design solution became obsolete. A new solution of RMS have been developed with conception following that of original Basic Design accommodating also safety measures implemented in RMS of NPP EMO units 1 and 2, and based on modem instrumentation and computer technique. Following the updating of Basic Design documentation the preparation of elaboration of RMS detailed design was carried on. In the frame of this preparation a review of possible suppliers of instrumentation satisfying the conception of radiation monitoring system and the extension of required deliveries has been made. Also criteria on RMS suppliers selection have been determined. The types of monitoring systems and equipment, as well as their quantities, have been specified based on updated Basic Design requirements and production profiles and possibilities of potential suppliers. The required parameters of measurements (including measurement geometry) have been evaluated, as well as requirements of legislation and requirements of proposed RMS architecture. (authors)

Radiobiological significance of radioactive contamination - summary assessment based on great number of measurements

Energy Technology Data Exchange (ETDEWEB)

Angelov, V [Civil Defence Administration, Sofia (Bulgaria); Bonchev, Ts; Mavrodiev, V; Kyrdzhilov, N [Sofia Univ. (Bulgaria). Fizicheski Fakultet

1996-12-31

In order to facilitate quantitative and qualitative characterisation of radioactive contamination the authors introduce a relative estimate of radionuclide activity by setting as a reference the most abundant element -Co-60 in the case of the Kozloduy NPP. The ratio {eta}{sub i} of the mean annual permissible concentration in air for each radionuclide (RPC-92) to that of Co-60 is calculated. It is found that {eta}{sub i} has the same or close values for groups of radionuclides, e.g. {eta}{sub i} = 2.10{sup -4} for {sup 238} Pu, {sup 239} Pu, {sup 240} Pu, {sup 241} Am, {sup 244} Cm; {eta}{sub i} = 5 for {sup 89} Sr, {sup 91} Y; {sup 93} Nb, {sup 134} Cs, {sup 137} Cs; {eta}{sub i} = 50 for {sup 55} Fe, {sup 63} Ni, {sup 95} Zr, {sup 95} Nb, {sup 140} Ba, {sup 140} La. Then it is compared to the experimentally measured values of the same quantity {eta}{sub iexp}, derived from surface contamination data. The ratio {eta}{sub iexp}/{eta}{sub i} is plotted against log {eta}{sub i}. The resulting nomograms give graphic representation of the radiobiological significance of various radionuclide groups. Data from different locations at the Kozloduy NPP are presented. It is found that the alpha emitter contamination has highest values in the Unit 1 (WWER-440) control rooms after repair. The Unit 5 (WWER-1000) has lower alpha contamination compared to WWER-440 units. 1 ref., 5 figs., 1 tab.

Construction of large-thickness sand cushions for NPP foundations

International Nuclear Information System (INIS)

Krantsfel'd, Ya.L.; Losievskaya, I.K.; Kovalenko, R.P.; Mutalipov, A.

1982-01-01

A study is made on some technological peculiarities of preparation of NPP foundations and control methods of foundation density. As an example the experience of cement-sand foundation construction for two 900 MW power-units at the Koeberg South Africa NPP is briefly described. The experience of artificial foundation construction at this NPP indicates both the possibility of obtaining the required quality of cement-sand cushions and commercial construction of large volume of such cushions by acceptable rates and the necessity of unification of work quality characteristics

Modernization of the oldest Swedish NPP

International Nuclear Information System (INIS)

Hagberth, Ronald

1998-01-01

OKG operates three BWR units of ABB design: Oskarshamn 1 with a net capacity of 440' MW, Oskarshamn 2 of 600 MW and Oskarshamn 3 of 1160 MW. Oskarshamn 1 NPP was commissioned in 1972 as the first commercial nuclear unit in Sweden. After more than twenty years of successful operation, the unit is now also the first reactor in Sweden to undergo a large safety modernization program. In the year 2000 the Oskarshamn 1 NPP will be modernized to a high level of safety standard and ready for operation for another period of at least 20 years. Experience gained can be used when modernizing other NPPs. The investment program for life extension is reasonable and shows that NPPs can be operated with an expected life span of more than 40 years at an ever-increasing safety level and still be very competitive in a deregulated market. (author)

Reactor plant for Belene NPP completion

International Nuclear Information System (INIS)

Dragunov, Yu. G.; Ryzhov, S. B.; Ermakov, D. N.; Repin, A. I.

2004-01-01

Construction of 'Belene' NPP was started at the end of 80-ties using project U-87 with V-320 reactor plant, general designer of this plant is OKB 'Gidropress'. At the beginning of 90-ties, on completing the considerable number of deliveries and performance of civil engineering work at the site the NPP construction was suspended. Nowadays, considering the state of affairs at the site and the work performed by Bulgarian Party on preservation of the equipment delivered, the most perspective is supposed to be implementation of the following versions in completing 'Belene' NPP: for completion of Unit 1 - reactor plant VVER-1000 on the basis of V-320 reactor with the maximum use of the delivered equipment (V-320M) having the extended service life and safety improvement; for Unit 2 - advanced reactor plant VVER-1000. For the upgraded reactor plant V-230M the basic solutions and characteristics are presented, as well as the calculated justification of strength and safety analyses, design of the reactor core and fuel cycle, instrumentation and control systems, application of the 'leak-before break' in the project and implementation of safety measures. For the modernised reactor plant V-392M the main characteristics and basic changes are presented, concerning reactor pressure vessel, steam generator, reactor coolant pump set. Design of NPP with the modernized reactor plant V-320M meets the up-to-date requirements and can be licensed for completion and operation. In the design of NPP with the advanced reactor plant the basic solutions and the equipment are used that are similar to those used in standard reactor plant V-320 and new one with VVER-1000 under construction and completion in Russia, and abroad. Compliance of reactor design with the up-to-date international requirements, considering the extended service life of the main equipment, shows its rather high potential for implementation during completion of 'Belene' NPP

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 4C. Paks NPP: Analysis and testing. Working material

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-07-01

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 involves comparative analysis of the seismic analysis results of the reactor building for soft soil conditions, derivation of design response spectra for components and systems; and upper range design response spectra for soft soil site conditions at Paks NPP.

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 4C. Paks NPP: Analysis and testing. Working material

International Nuclear Information System (INIS)

1996-01-01

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 involves comparative analysis of the seismic analysis results of the reactor building for soft soil conditions, derivation of design response spectra for components and systems; and upper range design response spectra for soft soil site conditions at Paks NPP

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

International Nuclear Information System (INIS)

Medeliene, D.; Alvers, M.

2001-01-01

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)

System approach as a tool for optimization of the dismantling technological process of NPP decommissioning

International Nuclear Information System (INIS)

Bylkin, B.K.; Shpitser, V.Ya.

1994-01-01

The concept of NPP unit decommissioning has been considered. Special attention was paid to the stage of dismantling of NPP unit equipment. Employment of systematic approach as a tool for optimization of dismantling processes permits formalizing manipulations with certified indices of quality and it permits an objective assessment of the dismantling technology level attained during designing as compared with the basic one. It seems appropriate to develop a basic project of NPP unit decommissioning as a technical means of planning, predicting and evaluating ecological and social aftereffects

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

International Nuclear Information System (INIS)

Tunturivuori, Lasse

2014-01-01

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)

Seismic strengthening of overhead roads between reactor buildings of WWER-1000 MW type NPP

International Nuclear Information System (INIS)

Stoyanov, G.; Jordanov, M.

2005-01-01

This paper presents results obtained during the upgrading design of overhead roads (OHR) between WWER-1000 MW Reactor Units at Kozloduy NPP. In order to avoid the deficiencies of OHR seismic capacity different approaches were developed based on the site and structure specifics. Overhead roads are precasted RC structures. They consist of pedestrian gallery and pipeline RC box, connecting reactor buildings with auxiliary building. They are mounted at approximately 10 m above ground level. The overhead roads are evaluated at their as-is status and a seismic upgrading of the structure is designed. The analysis of the upgraded structure is performed for Review Level Earthquake (RLE). Soil-Structure Interaction (SSI) effects are taken into account through equivalent soil springs with frequency adjusted stiffnesses. The upgraded structure is checked for conformance with the specially developed technical design specification based on International, US and Bulgarian standards and codes, taking into account site specific conditions. The general approach is consistent with up-to-date practice for evaluation and upgrade of nuclear power plant facilities. The existing site conditions and Owner's requirements are taken into account during development of the upgrading. The proposed upgrading measures can be divided in two major categories global and local. Special attention is paid to improvement of the ductile behavior of the structure through new detailing and upgrading of existing connection. These measures are grouped in two final design concepts and after a comparative study one of them is chosen for implementation. For the upgraded structure response spectra are derived at locations where equipment is attached. (authors)

Some results from a sociological study at Kozloduy NPP concerning atomic energy perspectives in the country

International Nuclear Information System (INIS)

Nanov, D.

1994-01-01

The results from an empirical sociological investigation among the personnel of the Kozloduj NPP are reported. The purpose of the study was to explore the opinions and assessment of the people working in the plant about their plant during the past years and at present. The necessary information was gathered from a representative excerpt of 231 persons. The questionnaire contained topics as: assessment of the operation and development of the plant as a whole and in comparison with other European NPPs; opinion about the security and safety of the plant; satisfaction by the work; necessity of additional qualification; assessment of payment and social policy of the plant. The results showed a variety of positive and negative assessment. The criticism expressed by this study point out the main significant problems of the station and will give rise to future efforts for eliminating the reasons of the deficiencies at work. (orig.)

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

International Nuclear Information System (INIS)

Tsiptsyura, R.D.

1985-01-01

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

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

International Nuclear Information System (INIS)

Gabriel, B.; Adrian, J.

2009-01-01

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

Temelin NPP commissioning experiences

International Nuclear Information System (INIS)

Hanus, V.

2002-01-01

The Building Permit for the Temelin NPP with four VVER units was issued in 1986, which is a long time ago. Since then, however, was taken a route that is very different from what anybody imagined. Described are the legislative and design changes and given is a current condition of the power plant

Licensing of the Ignalina NPP

International Nuclear Information System (INIS)

Kutas, S.

1999-01-01

Since 1991 State Nuclear Power Safety Inspectorate (VATESI) has regulated Ignalina NPP operation by issuing annual operating permits. Those have been issued following submission of specified documents by the Ignalina NPP that have been reviewed by VATESI. However, according to to the procedures that are now established in the Law on Nuclear Energy and subordinate regulations the use of nuclear energy in the Republic of Lithuania is subject to strict licensing. Therefore a decision about the licence for continued operation of unit 1 should be taken. Licence would be granted by VATESI in cooperation with the Ministry of Health, Ministry of Environment and the institutions of local authorities. Ignalina NPP presented to the VATESI safety analysis report (SAR) with other documents. SAR was made mainly by foreign experts and financed by European Bank for Reconstruction and Development (EBRD). VATESI in this process is supported by western regulators. A special project LAP - Licensing Assistance Project was launched to help VATESI perform licensing according western practices

NPP electrical price and tariff in the world

International Nuclear Information System (INIS)

Mochamad Nasrullah and Sriyana

2010-01-01

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)

The Chernobyl NPP decommissioning: Current status and alternatives

International Nuclear Information System (INIS)

Mikolaitchouk, H.; Steinberg, N.

1996-01-01

After the Chernobyl accident of April 26, 1986, many contradictory decisions were taken concerning the Chernobyl nuclear power plant (NPP) future. The principal source of contradictions was a deadline for a final shutdown of the Chernobyl NPP units. Alterations in a political and socioeconomic environment resulted in the latest decision of the Ukrainian Authorities about 2000 as a deadline for a beginning of the Chernobyl NPP decommissioning. The date seems a sound compromise among the parties concerned. However, in order to meet the data a lot of work should be done. First of all, a decommissioning strategy has to be established. The problem is complicated due to both site-specific aspects and an absence of proven solutions for the RBMK-type reactor decommissioning. In the paper the problem of decommissioning option selection is considered taking into account an influence of the following factors: relevant legislative and regulatory requirements; resources required to carry out decommissioning (man-power, equipment, technologies, waste management infrastructure, etc.); radiological and physical status of the plant, including structural integrity and predictable age and weather effects; impact of planned activities at the destroyed unit 4 and within the 30-km exclusion zone of the Chernobyl NPP; planed use of the site; socio-economic considerations

Conference: Nuclear Safety at the Ignalina NPP - Achievements and Challenges

International Nuclear Information System (INIS)

1999-01-01

Brief description of conference which took place in Vilnius on 8-9 April 1999 is presented. The aim of the international conference is to review the work carried out, to evaluate its influence on the nuclear safety, to get acquainted with the safety system of the Ignalina NPP. On December 31, the Ignalina NPP celebrated its 15 year anniversary. During that period the Ignalina NPP has produced more than 182 billion kWh of electricity. Nuclear power is not only immense economic benefit but also a syndrome of fear of an atomic bomb and the Chernobyl accident that has formed over the years. Numerous comprehensive international studies have been performed at the Ignalina NPP. After the Chernobyl accident many steps have been taken to improve the safety of the Ignalina NPP. The introduced changes guaranteed that the void coefficient remained negative in all possible circumstances. The Ignalina NPP is intensively preparing for licensing of unit 1

Plant level of automated control system at a NPP with RBMK reactor

International Nuclear Information System (INIS)

Vorob'ev, V.P.; Gorbunov, V.P.; Dmitriev, V.M.; Litvin, A.S.

1987-01-01

The functional structure of plant level automated control system (ACS) at NPP with RBMK-1000 reactors, its binding with the on-line control system of higher and lower levels, as well as engineering requirements to software and recommendations on composition of hardware components, are considered. NPP ACS is an organizational-engineering system consisting of computer facilities and binding aimed at solving management, economical, organizational and physical-engineering problems to control NPP more effectively. The system carries out data acquisition, preliminary processing, analysis, transmission and representation for users to accept solutions for NPP operation by operative and management personnel. The main aim of integrated NPP ACS is the control development and increase of NPP economical efficiency, the increase of electric and heat energy production, the optimization of the production distribution between units, the development of production and economic NPP control

Strengthening the control on radioactive sources - Cernavoda NPP operating experience

International Nuclear Information System (INIS)

Daian, I.; Simionov, V.

2005-01-01

This paper presents the national legal frame governing the radioactive source management, legislative requirements introduced during last years and current status of controlled radioactive sources program at Cernavoda NPP. 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. The legal representative of the nuclear power production sector in Romania is 'Nuclearelectrica' S.A. National Company (SNN). SNN is a governmental company controlled by the Ministry of Industry and Trade. The company has headquarters in Bucharest and three subsidiaries: - CNE-PROD Cernavoda (CNE-PROD), operating the Cernavoda NPP - Unit 1; - CNE-INVEST Cernavoda, in charge with the completion of Unit 2 and with the preservation of Units 3,4,5; - Nuclear Fuel Plant in Pitesti (FCN). Unit 1 is in commercial operation since December 2, 1996, Unit 2 is under construction (80% completed) and Units 3, 4, 5 are under preservation. The operation of Cernavoda NPP implies use of radioactive sources that may present a significant risk to health, property and the environment when control is lost. Within the last years CNCAN issued new regulations stating clear responsibilities for the different institutions involved in radioactive materials control programs. To manage radioactive sources in a safe way CNE-PROD established and revised the Controlled Radioactive Sources Program, as part of Station Radiation Protection Regulation, ensuring strict recording of the radioactive sources and their usage, ensuring physical and radiological security, protecting the personnel, members of the public and the environment from the hazards of ionizing radiation during the life cycle of the plant, including decommissioning. (authors)

Strengthening the control on radioactive sources - Cernavoda NPP operating experience

International Nuclear Information System (INIS)

Daian, I.; Simionov, V.

2005-01-01

Full text: This paper presents the national legal frame governing the radioactive source management, legislative requirements introduced during last years and current status of controlled radioactive sources program at Cernavoda NPP. 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. The legal representative of the nuclear power production sector in Romania is 'Nuclearelectrica' S.A. National Company (SNN). SNN is a governmental company controlled by the Ministry of Industry and Trade. The company has headquarters in Bucharest and three subsidiaries: - CNE-PROD Cernavoda (CNE-PROD), operating the Cernavoda NPP - Unit 1; - CNE-INVEST Cernavoda, in charge with the completion of Unit 2 and with the preservation of Units 3,4,5; - Nuclear Fuel Plant in Pitesti (FCN). Unit 1 is in commercial operation since December 2, 1996, Unit 2 is under construction (80% completed) and Units 3, 4, 5 are under preservation. The operation of Cernavoda NPP implies use of radioactive sources that may present a significant risk to health, property and the environment when control is lost. Within the last years CNCAN issued new regulations stating clear responsibilities for the different institutions involved in radioactive materials control programs. To manage radioactive sources in a safe way CNE-PROD established and revised the Controlled Radioactive Sources Program, as part of Station Radiation Protection Regulation, ensuring strict recording of the radioactive sources and their usage, ensuring physical and radiological security, protecting the personnel, members of the public and the environment from the hazards of ionizing radiation during the life cycle of the plant. (authors)

Enemona's Company experience in management of complex construction and modernization projects in sectors of industry and energetics

International Nuclear Information System (INIS)

Kalionski, V.

2005-01-01

The purpose of this paper is to present the Enemona's Company experience, gained during the management of complex projects related to Kozloduy NPP Modernization Program, enriched during the long-term collaboration with the international companies which are the executors of modernization projects. For the successful implementation of tasks on Framatom, Westinghouse, Atomenergo export projects, an exchange of process transfer, managerial practices were established between the Employers companies and Enemona Company, which along with the use of material resources, organization and personnel gave Enemona opportunity to implement and optimize goals that were set to the company. Some principles, approaches and methods of works have been established, based on strict scientific methods and practices that support Enemona to be competitive in order to assume fulfillment of similar projects not only at Kozloduy NPP site, but also at new projects and sites including the challenge for the erection of Belene NPP. In order to meet requirements of foreign companies, Enemona is able to apply new technologies and achievements in assurance of high quality of repair and installation activities on construction of new objects or their modernization

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.).

Feed water distribution pipe replacement at Loviisa NPP

Energy Technology Data Exchange (ETDEWEB)

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

1996-12-31

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.).

ICEMENERG technologies of water treatment applied at Cernavoda NPP Unit 1

International Nuclear Information System (INIS)

Stanca, Angela; Bolma, Aurelia; Serbanescu, Agnes; Raducanu, Alice

2002-01-01

The paper presents the ICEMENERG technologies for water treatment applied at Cernavoda Unit 1, the treatment of the additional water for power steam generators and the chemical treatment of cooling system water. The requirements for quality of water totally demineralized as imposed by the AECL-ANSALDO consortium are as following: electrical conductivity, < 0.2 mS/cm; total silicon, <0.02 mg/L; ionic silicon, <0.01 mg/L; sodium, < 0.05 mg/L; TOC, <0.300 mg/L. These requirements raise rather difficult problems to be solved because the raw water source in case of Cernavoda NPP is Danube River which presents a raising trend of organic and inorganic contamination. Accordingly, experiments at laboratory scale reproducing the entire technological flow were conducted. The following operations were studied: pretreatment with limewash, ferric chloride (with and without coagulation additives); demineralization with ion exchangers of Purolite and Amberlite types. The system consisted of a cationic stage, formed of an strongly acid step with countercurrent recovery and an anionic stage formed of two steps, namely, a weakly basic step and a strongly basic step with recovery inserted; finishing on mixed bed. The paper presents also the chemical treatment/conditioning of the cooling loop of turbine condenser. The Cernavoda NPP cooling system is an open system with a single flow of cooling water comprising two systems, namely, the circulation water system ensuring the steam condenser cooling and the servicing water system ensuring the cooling of heat exchangers in the recirculated water circuit (RCWS), the turbine oil coolants, the coolants of auxiliary steam as well as the emergency core cooling system. Studies were conducted to ensure the chemical conditioning of the raw water from Danube River, particularly, to destroy and remove the shells, the algae and other components. Finally, the following four steps of conditioning the water of the cooling system are summarized: 1

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

International Nuclear Information System (INIS)

Dinev, D.

2005-01-01

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

Indicators for monitoring of safety operation and condition of nuclear power stations

International Nuclear Information System (INIS)

Manova, D.

2001-01-01

A common goal of all employees in the nuclear power field is safety operation of nuclear power stations. The evaluation and control of NPP safety operation are a part of the elements of safety management. The present report is related only to a part of the total assessment and control of the plant safety operation, namely - the indicator system for monitoring of Kozloduy NPP operation and condition. (author)

Computer-aided design system for a complex of problems on calculation and analysis of engineering and economical indexes of NPP power units

International Nuclear Information System (INIS)

Stepanov, V.I.; Koryagin, A.V.; Ruzankov, V.N.

1988-01-01

Computer-aided design system for a complex of problems concerning calculation and analysis of engineering and economical indices of NPP power units is described. In the system there are means for automated preparation and debugging of data base software complex, which realizes th plotted algorithm in the power unit control system. Besides, in the system there are devices for automated preparation and registration of technical documentation

Human Resources Training Requirement on NPP Operation and Maintenance

International Nuclear Information System (INIS)

Nurlaila; Yuliastuti

2009-01-01

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)

A Preliminary Study on the Containment Integrity following BIT Removal for Kori NPP Unit 3,4

Energy Technology Data Exchange (ETDEWEB)

Song, Dong Soo; Byun, Choong Sup [KEPRI, Nuclear Power Generation Laboratory, Daejeon (Korea, Republic of); Jo, Jong Young [ENERGEO Inc., Sungnam (Korea, Republic of)

2008-05-15

The Boron Injection Tank (BIT) is to provide high concentrated boric acid to the reactor in order to mitigate the consequences of postulated Main Steam Line Break accidents (MSLB). Although BIT plays an important role in mitigating the accident, high concentration of 20,000ppm causes valve leakage, pipe clog, precipitation and continuous heat tracing have to be provided. This paper is for the feasibility study of containment integrity using CONTEMPT code for BIT removal of Kori Nuclear Power Plant (NPP) Unit 3, 4.

A Preliminary Study on the Containment Integrity following BIT Removal for Kori NPP Unit 3,4

International Nuclear Information System (INIS)

Song, Dong Soo; Byun, Choong Sup; Jo, Jong Young

2008-01-01

The Boron Injection Tank (BIT) is to provide high concentrated boric acid to the reactor in order to mitigate the consequences of postulated Main Steam Line Break accidents (MSLB). Although BIT plays an important role in mitigating the accident, high concentration of 20,000ppm causes valve leakage, pipe clog, precipitation and continuous heat tracing have to be provided. This paper is for the feasibility study of containment integrity using CONTEMPT code for BIT removal of Kori Nuclear Power Plant (NPP) Unit 3, 4

Brief review of 1995 events at Ukraine's NPPs. Report on the ChNPP unit 1 of November 27.1995 ''strict regime area premises contamination after reactor refuelling''

International Nuclear Information System (INIS)

Lomakin, V.

1996-01-01

In 1995 number of events at NPP had considerably decreased as compared with that for previous 1992-94, amounted in 87. In particular, as compared with 1994, events number had decreased by 36%. It characterizes a total improvement of current NPPs safety level during 1995. The most events number as recalculated per single unit was at the South Ukraine NPP - 8. The least - at the ChNPP - 4 in total, and 1,3 per unit. Decreasing of a total events number for 1995 did also accordingly reduce other quantitative system indices which reflect state of NPPs safety level. Among event root causes, as it was before, ''administrative management deficiencies'' and ''staff training deficiencies'' are still dominanting. ''Human factor'' issues are still pending for NPPs safety, despite of considerable efforts applied to improved efficiency of correcting measures aimed at their solution. Of sufficient importance for events system development in 1995 was the work implemented at the SSTC NRS/NRA as regards preparation of modern edition of the ''Regulation on order of NPP events investigation and account''. The IAEA/Nuclear Safety Division rendered a sufficient assistance for this work to be done through arrangement of advisory help to Ukrainian specialists from international experts. 2 figs, 8 diagrams

Novelly formed products of the interaction of fuel with construction materials of the 4th unit of Chernobyl NPP

International Nuclear Information System (INIS)

Borovoj, A.A.; Galkin, B.Ya.; Drapchinskij, L.V.; Krinitsyn, A.P.; Pazukhin, Eh.M.; Petrov, B.F.; Pleskachevskij, L.A.; Checherov, K.P.

1991-01-01

Radiation environment and position of fuel-containing masses in the bubbler pond of the 4th unit of the Chernobyl NPP are described. Classification of the products of fuel interaction with structural materials is given. Amounts of fuel on the 1st and 2nd floor of the bubbler pond are estimated. Postaccident pictures of the premises of the bubbler pond are presented for the first time

Knowledge Management Aspects of Decommissioning. Case Study

International Nuclear Information System (INIS)

Pironkov, Lyubomir

2017-01-01

Kozloduy NPP: Units 5&6, type VVER-1000 - in operation. SE RAW SD “Decommissioning of units 1-4” (type VVER-440); SD “Radioactive Waste – Kozloduy”; SD “National Repository for Radioactive Waste“; SD “Permanent Repository for Radioactive Waste – Novi Han”. Decommissioning Strategy: Strategy Target: “Brown Field”. Initial Version: Safe enclosure – completing by 2050. Updated Version: Continuous dismantling of equipment; Completing the process of Decommissioning of Units 1-4 by 2030. Major Phases: 1.Pre-decommissioning activities; 2.Facility shutdown activities; 3.Procurement of equipment; 4.Dismantling activities; 5.Treatment of RAM and RAW and delivery for disposal; 6.Site management and support; 7.Project management and engineering; 8.Management of SNF and activated materials

Preventing degradation and in-service inspection of NPP steam generator

International Nuclear Information System (INIS)

Ding Xunshen

1999-01-01

The author describes the degradation of steam generator tubes in initial operating stage of France NPP. The author emphatically presents the preventive measures to tackle degradation and In-service inspection of Daya Bay NPP 1 unit as a guarantee of safety operation, including secondary side water chemistry monitoring and controlling, leakage rate monitoring, eddy-current inspection, mechanical cleaning, cleanliness inspection, foreign objects removal and etc

Trial operation of TVS-2 at Balakovo NPP. Analysis of results and further modernization

International Nuclear Information System (INIS)

Vasilchenko, I.; Molchanov, V.; Pavlovichev, A.; Novikov, A.; Enin, A.

2006-01-01

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

Bituminization of liquid radioactive wastes. Part 2

International Nuclear Information System (INIS)

Gradev, G.D.; Ivanov, V.I.; Stefanova, I.G.; Milusheva, A.G.; Guteva, E.S.; Stefanov, G.I.; G'oshev, G.S.

1991-01-01

The leaching of alcaline cations, as well as of chloride, sulphate and borate anions and radionuclides was studied. The leach rates and the diffusion coefficients of some of the incorporated ions for the salt-bitumen products obtained from Bulgarian bitumens (road bitumen PB 66/90 and hydroinsulating bitumen HB 80/25) and salts (chlorides, sulphates, borates, salt mixtures modelling the concentrate from the evaporators at the Kozloduy NPP and radionuclides) were determined. Most suitable for technological research under the conditions of the Kozloduy NPP proved to be the road bitumen PB 66/90 with softening temperature at 48 o C. The optimum bitumen/salt ratio is found to be about 1.2. Admixtures of natural inorganic sorbents (clinoptiolite, vermiculite and bentonite) in quantities of 5-10% are found to decrease the leaching of radionuclides from the bitumen products. The action of the hydromica vermiculite is particularly pronounced. 6 tabs., 5 refs

Calculational-experimental examination and ensuring of equipment and pipelines seismic resistance at starting and operating water-cooled and moderated reactor WWER-type NPPs. Final report from 1 November 1994 to 31 October 1995

International Nuclear Information System (INIS)

Kaznovski, S.

1996-01-01

The method for examination and ensuring of equipment seismic resistance is based on the resonance character of the seismic influence on structures and equipment. Values of natural dynamic characteristics are obtained by using external source for exciting the vibrations of the testing unit. These characteristics with the floor response spectra enabled calculations of the seismic resistance. For tests of Kozloduy NPP equipment a simple shock method was used. The presentation includes the list of inspected equipment. The calculations of the equipment seismic resistance were carried out on the basis of Russian and International standards and demands

Analysis of electrical systems from Cernavoda NPP - Unit 1 based on commissioning activity

International Nuclear Information System (INIS)

Goia, M.L.; Manolescu, I.

1996-01-01

Several design solutions regarding the electrical part of Cernavoda NPP Unit 1 station auxiliaries are discussed in this paper. The solutions mentioned may have different variants which should be taken into consideration in the design of Units U2 - U5. This work offers an ample debate on such matters as the supply source connection of the station auxiliaries, the use of two different voltages for the mean voltage (MV) supply, the consequence of the lack of breakers on the 24 kV part of station auxiliary transformers T03 - T04, the protection devices non correlated with the breakers to which they react, as well as the consequences of low subtransient reactance of the new stand-by Diesel generators. Besides these design solutions that can influence the station auxiliaries reliability, matters as malfunctioning of the dry type MV/LV transformers and unreliable behaviour of some MV composite insulators are also discussed. For some of the above mentioned problems the authors proposed several solutions. (authors). 1 fig., 1 tab

Radiation monitoring in the NPP environment, control of radioactivity in NPP-environment system

International Nuclear Information System (INIS)

Egorov, Yu.A.

1987-01-01

Problems of radiation monitoring and control of the NPP-environment system (NPPES) are considered. Radiation control system at the NPP and in the environment provides for the control of the NPP, considered as the source of radioactive releases in the environment and for the environmental radiation climate control. It is shown, that the radiation control of the NPP-environment system must be based on the ecological normalization principles of the NPP environmental impacts. Ecological normalization should be individual for the NPP region of each ecosystem. The necessity to organize and conduct radiation ecological monitoring in the NPP regions is pointed out. Radiation ecological monitoring will provide for both environmental current radiation control and information for mathematical models, used in the NPPES radiation control

Technology for NPP decantate treatment realized at Kola NPP

International Nuclear Information System (INIS)

Stakhiv, Michael; Avezniyazov, Slava; Savkin, Alexander; Fedorov, Denis; Dmitriev, Sergei; Kornev, Vladimir

2007-01-01

At Moscow SIA 'Radon' jointly with JSC 'Alliance Gamma', the technology for NPP Decantate Treatment was developed, tested and realized at Kola NPP. This technology consists of dissolving the salt residue and subsequent treatment by ozonization, separation of the deposits formed from ozonization and selective cleaning by ferro-cyanide sorbents. The nonactive salt solution goes to an industrial waste disposal site or a repository specially developed at NPP sites for 'exempt waste' products by IAEA classification. This technology was realized at Kola NPP in December 2006 year. At this time more than 1000 m 3 of decantates log time stored are treated. It allows solving very old problem to empty decantates' tanks at NPPs in environmentally safe manner and with high volume reduction factor. (authors)

Retrofitting of NPP Computer systems

International Nuclear Information System (INIS)

Pettersen, G.

1994-01-01

Retrofitting of nuclear power plant control rooms is a continuing process for most utilities. This involves introducing and/or extending computer-based solutions for surveillance and control as well as improving the human-computer interface. The paper describes typical requirements when retrofitting NPP process computer systems, and focuses on the activities of Institute for energieteknikk, OECD Halden Reactor project with respect to such retrofitting, using examples from actual delivery projects. In particular, a project carried out for Forsmarksverket in Sweden comprising upgrade of the operator system in the control rooms of units 1 and 2 is described. As many of the problems of retrofitting NPP process computer systems are similar to such work in other kinds of process industries, an example from a non-nuclear application area is also given

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

International Nuclear Information System (INIS)

Bobric, Elena; Bucur, Cristina; Popescu, Ion; Simionov, Vasile; Titescu, Gheorghe; Varlam, Carmen

2010-01-01

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)

Numerical Simulation of Measurements during the Reactor Physical Startup at Unit 3 of Rostov NPP

Science.gov (United States)

Tereshonok, V. A.; Kryakvin, L. V.; Pitilimov, V. A.; Karpov, S. A.; Kulikov, V. I.; Zhylmaganbetov, N. M.; Kavun, O. Yu.; Popykin, A. I.; Shevchenko, R. A.; Shevchenko, S. A.; Semenova, T. V.

2017-12-01

The results of numerical calculations and measurements of some reactor parameters during the physical startup tests at unit 3 of Rostov NPP are presented. The following parameters are considered: the critical boron acid concentration and the currents from ionization chambers (IC) during the scram system efficiency evaluation. The scram system efficiency was determined using the inverse point kinetics equation with the measured and simulated IC currents. The results of steady-state calculations of relative power distribution and efficiency of the scram system and separate groups of control rods of the control and protection system are also presented. The calculations are performed using several codes, including precision ones.

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

International Nuclear Information System (INIS)

Bokor, J.; Gaspar, P.; Hetthessy, J.; Szabo, G.

1998-01-01

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)

New appraisement of siting for a NPP on Mures river

International Nuclear Information System (INIS)

Traian Mauna

2010-01-01

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)

Calculation of the effectiveness of manual control rods for the reactor of Ignalina NPP Unit 2

International Nuclear Information System (INIS)

Bubelis, E.; Pabarcius, R.

2001-01-01

On the basis of one of the recent databases of the reactor of Ignalina NPP Unit 2, calculations of the effectiveness of separate manual control rods, groups of manual control rods and axial characteristic of effectiveness of separate manual control rods were performed. The results of the calculations indicated, that all analyzed separate manual control rods have approximately the same effectiveness, which doesn't depend on the location of a control rod in the reactor core layout Manual control rod of the new design has about 10% greater effectiveness than manual control rod of the old design. (author)

Some results of periodical analysis of the behavior of unit 4 at the Dukovany NPP - II

International Nuclear Information System (INIS)

Jirsa, P.

1993-01-01

The results of a detailed spectral analysis of noise signals recorded at the unit 4 reactor of the Dukovany NPP during and after the start-up stage are presented. The changes in the noise source signal spectra during the start-up and in normal operation were evaluated by multidimensional autoregression analysis. The temperature dependence of the signal spectra peaks from individual detectors is described. The sources of the peaks at 27.9 and 37 Hz during normal operation were identified as standing pressure waves in the primary circuit of the reactor. 3 tabs., 23 figs., 6 refs

Automatic regulation of the feedwater turbo-pump capacity for the single-turbine 1000 MW NPP unit

International Nuclear Information System (INIS)

Pavlysh, O.N.; Garbuzov, I.P.; Reukov, Yu.N.

1985-01-01

A schematic of the flow regulators (FR) of feedwater turbo-pumps (FTP) for the single-turbine 1000 MW NPP unit is presented. The FR operate in response to feedwoter signals from FTP or in response to FTP rotor rotational speed and control automatic speed governars. The FR automatic regulation ensures limitation of FTP rotor maximum rotational speed at a feedwater flow rate excess equal to 3600 T/h. The transients in the automatic regulation system are considered. Production tests of FTP FR confirmed the FR operation reliability and the right choice of the regulator concept and structure

Configuration management and change control at Cernavoda NPP Unit 1

International Nuclear Information System (INIS)

Gheorghiu, Virgil

1998-01-01

Effective configuration management requires that: 1. the design basis of station structures, systems, equipment and components be maintained at all times; 2. only accurate and approved technical, operational and maintenance information is available for performance of station activities; 3. correct operating manuals, flowsheets, operating sequences, operating task and training manuals are prepared and maintained currently. Design Engineering at Cernavoda NPP is primarily the responsibility of the Engineering Services Department supported if necessary by the Technical Unit. The key elements needed to achieve excellence in design engineering support for station operation, including design process and implementation of modification are investigated by answering the questions: 1. What is the station expectation for design change control?; 2. How is this provided?. Concerning design, the following aspects are stressed: Detailed Design Development; Design Verification; Design Change Implementation. The present design process is auditable and well documented. It consists of detailed design development, and design output documents such as applicable drawings, procurement specifications, installation and test requirement and the results of design and safety reviews. The design change implementation does not proceed until an Inspection Test Plan has been developed and approved as required. (author)

Dukovany NPP operation

International Nuclear Information System (INIS)

Vlcek, Jaroslav

2010-01-01

The topics discussed include: Dukovany NPP among CEZ Group power plants; International missions at the plant; Plant operation results; and Strategic goals and challenges. Historical data are presented in the graphical form, such as the unit capacity factor, unplanned capability loss factor, unplanned automatic scrams, fuel reliability, industrial safety accident rate, collective radiation exposure, WANO index, power generation data, and maximum achievable power by the end of year. Also discussed were the company culture and human resources, maintenance, power uprate, and related phenomena. (P.A.)

Challenges of Ignalina NPP Decommissioning - View of Lithuanian Operator

International Nuclear Information System (INIS)

Aksionov, P.

2017-01-01

The state enterprise Ignalina Nuclear Power Plant (INPP) operates 2 similar design units of RBMK-1500 water-cooled graphite-moderated channel-type power reactors (1500 MW electrical power). INPP is carrying out the decommissioning project of the 2 reactors which includes: -) the retrieval of the spent nuclear fuel from the power units and its transportation into the Interim Spent Fuel Storage Facility; -) equipment and building decontamination and dismantling; -) radioactive waste treatment and storage; and -) the operation of key systems to ensure nuclear, radiation and fire protection. Ignalina NPP decommissioning project is planned to be completed by 2038. The presentation will be focused on the ongoing decommissioning activities at Ignalina NPP. The overview of main aspects and challenges of INPP decommissioning will be provided

Approach to training the operators of WWER-440 reactors

International Nuclear Information System (INIS)

Pironkov, L.; Minakova, R.

2002-01-01

The paper has three parts. (1) Personnel Training and Qualifications (2) Description of Kozloduy NPP Training and Qualification System (TQS) built in the last 7 years and its interfaces with the Certification System and (3) Application of the TQS for the Senior Reactor Operator (SRO). (author)

Bituminization of liquid radioactive wastes. Part 1

International Nuclear Information System (INIS)

Gradev, G.D.; Ivanov, V.I.; Stefanova, I.G.; Milusheva, A.G.; Guteva, E.S.; Zhelyazkov, V.T.; Stefanov, G.I.; G'oshev, G.S.

1991-01-01

Salt-bitumen products are produced by the method of 'hot mixing' of some Bulgarian bitumens (road bitumen PB 66/99 and the hydroinsulating bitumen HB 80/25) and salts (chlorides, sulphates, borates, salt mixtures modelling the liquid waste from nuclear power plants) in different ratios to determine the optimum conditions for bituminization of liquid radioactive waste. The penetration, ductility and softening temperature were determined. The sedimentation properties and the thermal resistance of the various bitumen-salt mixtures were studied. The most suitable bitumen for technological research at the Kozloduy NPP was found to be the road bitumen PB 66/90 with softening temperature at 48 o C. The optimum amount of salts incorporated in the bitumen - about 45% - was found. No exothermal effects were observed in the bituminization process in the temperature range of up to 200 o C. The results obtained may be useful in the elaboration of a technology for bituminization of liquid radioactive wastes in the Kozloduy NPP. 4 tabs., 5 figs., 4 refs

Decommissioning of Brennilis NPP

International Nuclear Information System (INIS)

Baize, Jean-Marc

1998-01-01

This EDF press communique give information related to the decommissioning of the Brennilis NPP. The following five items are developed in this report: 1. the level-2 decommissioning operations at the Brennilis NPP; 2. the Brennilis NPP, a pilot operation from the commissioning up to the decommissioning; 3. history of the Brennilis NPP decommissioning; 4. the types of radioactive wastes generated by the Brennilis NPP decommissioning; 5. the Brennilis NPP - a yard management as a function of the wastes. The document contains also seven appendices addressing the following subjects: 1. the share of decommissioning assigned to EDF and the decommissioning steps; 2. the EDF installations in course of decommissioning; 3. the CEA decommissioned installations or in course of decommissioning; 4. regulations; 5. costs; 6. waste management - principles; 7. data on the decommissioning yard

Corrosion strength monitoring of NPP component residual lifetime

International Nuclear Information System (INIS)

Denisov, V.G.; Belous, V.N.; Arzhaev, A.I.; Shuvalov, V.A.

1994-01-01

Importance of corrosion and fatigue monitoring; types of corrosion determine the NPP equipment life; why automated on-line corrosion and fatigue monitoring is preferable; major stages of lifetime monitoring system development; major groups of sensors for corrosion and strength monitoring system; high temperature on-line monitoring of water chemistry and corrosion; the RBMK-1000 NPP unit automatic water chemistry and corrosion monitoring scheme; examples of pitting, crevice and general corrosion forecast calculations on the basis of corrosion monitoring data; scheme of an experimental facility for water chemistry and corrosion monitoring sensor testing. 2 figs., 4 tabs

The role of the international Chornobyl Center in coordinating and conducting the work related to Chornobyl NPP closure and creation the new employment opportunities in Slavutych

International Nuclear Information System (INIS)

Nosovskij, A.V.

2001-01-01

The Slavutych division of the international Chornobyl Center (ICC) actively conducts its work in Slavutych from 1997. The following work was conducted during the last years: Documentation on the ChNPP 1-st Unit and 2-nd Unit decommissioning was developed. Comprehensive engineering and radiation survey of the 1-st Unit was conducted. Decommissioning database was created. On demand of Chornobyl NPP, the work on development the following documents was conducted: The 3-rd Unit shutdown program. Comprehensive program on ChNPP decommissioning. ChNPP personnel and Slavutych residents social protection program

Decommissioning of NPP A-1

International Nuclear Information System (INIS)

Anon

2009-01-01

In this presentation the Operation history of A1 NPP, Project 'Decommissioning of A1 NPP' - I stage, Project 'Decommissioning of A1 NPP ' - II stage and Next stages of Project 'Decommissioning of A1 NPP ' are discussed.

The post-accidents exploitation of Chernobyl NPP

International Nuclear Information System (INIS)

Nosovskij, A.V.

1996-01-01

Problems facing the Chernobyl NPP personnel since its commissioning and during its post-accident operation are considered. The accomplished measures on improving the power units safety, normalization of the radiation situation as well as the impact of psychological factor at the safety culture level are discussed

Preliminary results from uranium/americium affinity studies under experimental conditions for cesium removal from NPP ''Kozloduy'' simulated wastes solutions

International Nuclear Information System (INIS)

Nikiforova, A.; Kinova, L.; Peneva, C.; Taskaeva, I.; Petrova, P.

2005-01-01

We use the approach described by Westinghouse Savannah River Company using ammonium molybdophosphate (AMP) to remove elevated concentrations of radioactive cesium to facilitate handling waste samples from NPP K ozloduy . Preliminary series of tests were carried out to determine the exact conditions for sufficient cesium removal from five simulated waste solutions with concentrations of compounds, whose complexing power complicates any subsequent processing. Simulated wastes solutions contain high concentrations of nitrates, borates, H 2 C 2 O 4 , ethylenediaminetetraacetate (EDTA) and Citric acid, according to the composition of the real waste from the NPP. On this basis a laboratory treatment protocol was created. This experiment is a preparation for the analysis of real waste samples. In this sense the results are preliminary. Unwanted removal of non-cesium radioactive species from simulated waste solutions was studied with gamma spectrometry with the aim to find a compromise between on the one hand the AMP effectiveness and on the other hand unwanted affinity to AMP of Uranium and Americium. Success for the treatment protocol is defined by proving minimal uptake of U and Am, while at the same time demonstrating good removal effectiveness through the use of AMP. Uptake of U and Am were determined as influenced by oxidizing agents at nitric acid concentrations, proposed by Savannah River National laboratory. It was found that AMP does not significantly remove U and Am when concentration of oxidizing agents is more than 0.1M for simulated waste solutions and for contact times inherent in laboratory treatment protocol. Uranium and Americium affinity under experimental conditions for cesium removal were evaluated from gamma spectrometric data. Results are given for the model experiment and an approach for the real waste analysis is chosen. Under our experimental conditions simulated wastes solutions showed minimal affinity to AMP when U and Am are most probably in

Baltic NPP Project specifics and current status

International Nuclear Information System (INIS)

2011-01-01

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

Problems of complex automation of process at a NPP

International Nuclear Information System (INIS)

Naumov, A.V.

1981-01-01

The importance of theoretical investigation in determining the level and quality of NPP automation is discussed. Achievements gained in this direction are briefly reviewed on the example of domestic NPPs. Two models of the problem solution on function distribution between the operator and technical means are outlined. The processes subjected to automation are enumerated. Development of the optimal methods of power automatic control of power units is one of the most important problems of NPP automation. Automation of discrete operations especially during the start-up, shut-down or in imergency situations becomes important [ru

Benchmark study for the seismic analysis and testing of WWER type NPPs. Final report of a co-ordinated research project

International Nuclear Information System (INIS)

2000-10-01

This report is the final results of a five-year IAEA Coordinated Research Project (CRP) launched in 1992. The main goal was the harmonization of criteria and methods used in Member States in seismic reassessment and upgrading of existing nuclear power plants. To this aim, most of the activities have been focused on a benchmarking exercise related to a mixed numerical and experimental dynamic analysis carried out on two reference units of WWER reactors (WWER-1000 and WWER-440/213): Kozloduy NPP Units 5/6 and PAKS NPP. Twenty-four institutions from 13 countries participated in the CRP, and two other institutions from Japan contributed to the CRP informally. The objective of this TECDOC is to provide a consistent and comprehensive summary of the results of the work performed in the CRP through the preparation of a ''self-standing'' report with the general conclusion of the programme: a great deal of information from the Background Documents has been included in this report with a set of recommendations for future work in this field

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

Energy Technology Data Exchange (ETDEWEB)

Pwani, Henry; James, J. [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

2013-10-15

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.

Radiological characterisation of V1 NPP technological systems and buildings - Activation

International Nuclear Information System (INIS)

Kristofova, Kristina; Rapant, Tibor; Svitek, Jaroslav

2012-01-01

V1 NPP at Jaslovske Bohunice site has been finally shutdown after 28 years of successful operation in 2006 (Unit 1) and 2008 (Unit 2). At present, both units are finally shutdown and since July 2011 under decommissioning license. The preparation of V1 NPP decommissioning has been supported and partly financed by the Bohunice International Decommissioning Support Fund (BIDSF), under the administration of the European Bank for Reconstruction and Development. From 06/2008 to 12/2011 AMEC Nuclear Slovakia, together with partners STM Power and EWN GmbH, carried out BIDSF B6.4 project - Decommissioning database development (DDB). The main purpose of the B6.4 project was to develop a physical and radiological inventory database to support V1 NPP decommissioning process planning and performance. One of the specific deliverable tasks within the B6.4 project was deliverable D12 - Characterization of activated equipment and civil structures based on measurement, sampling and analyses performed on the samples. The scope of deliverable services within D12 task consisted of: 1. Categorization of activated components ; 2. Development of single working programs for their radiological monitoring and sampling ; 3. Preparation of sampling device and revision of all handling equipment; 4. Dose rate monitoring and sampling of: - Civil structures from reactors shaft on both units ; - Components placed in HLW storage, (so called 'Mogilnik') - connection rods, absorbers ; of control rod assemblies and neutron flux measurement channels ; - Reactor pressure vessel and shielding assemblies at both units of V1 NPP, reactor; internals from Unit 2 of V1 NPP; 5. Analysis of samples ; 6. Determination of radiological inventory ; 7. Import of radiological data for activated components into DDB. During sampling, mainly remotely controlled sampling device and radiation resistant camera with LED lightening for visual checking of all performed activities was used. In total, 125 samples have been taken

Use of operator training and simulating complexes for development of NPP APCS

International Nuclear Information System (INIS)

Malkin, S.D.; Rakitin, I.D.; Sivokon', V.P.

2002-01-01

The evolution of NPP educational facilities - from systems of training of personnel to power simulating systems for the development of Automatic Process Control System (APCS) and safety analysis is followed. High efficiency of simulating systems application for the development of NPP APCS including optimization of man-machine system interface was shown by experiments of USA, France, Japan, United Kingdom, conforming examples were given [ru

Maintenance training centre at NPP Paks, Hungary

International Nuclear Information System (INIS)

Babos, K.

1996-01-01

The lecture shows the feature of WWER-440/213 units maintenance, the existing maintenance training system, the necessity of the change in maintenance training system at NPP Paks. The author introduces the would-be maintenance training centre, the training facilities and the main tasks related to the maintenance training. (author)

Mochovce NPP simulator

International Nuclear Information System (INIS)

Ziakova, M.

1998-01-01

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

Main principles of the Chernobyl' NPP zone development

International Nuclear Information System (INIS)

Ignatenko, E.I.; Komarov, V.I.; Zverkov, V.V.; Proskuryakov, A.G.

1989-01-01

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

On improving the NPP construction long-term planning

International Nuclear Information System (INIS)

Solov'ev, M.M.

1980-01-01

General approaches to solving the problems of long-term planning of the construction-mounting work volume and introduction of power capacities at different paces of power unit commission and norms of construction time are considered. Problems associated with location and development of subsidiary industries providing NPP construction are discussed. It is shown that decrease of WWER-1000 reactor type NPP construction time from 24 to 12 months results in reduction of required high-skilled engineers, managerial staff, unique construction mechanisms and engines as well as in improvement of conditions for conducting measures on work arrangement during preparation of construction industry and mounting of the first assemblies

The politics of nuclear safety regulation

International Nuclear Information System (INIS)

Adam, G.

2002-01-01

The paper discusses political aspects of decision making about the safety of nuclear power plants especially in Eastern Europe and in connection with the enlargement of the European Union. The problem of the Kozloduy NPP safety is also discussed. Recommendations on the policy and tasks for nuclear regulators are given

Optimization of radiation protection at Bohunice NPP

International Nuclear Information System (INIS)

Dobis, L.; Svitek, J.

2003-01-01

Bohunice Nuclear Power Plant is situated in south - western part of Slovakia about 50 km away from Bratislava. There are four PWR reactors 440 MW e each - two units with reactors WWER - 230 (V1 NPP) and two units with WWER - 213 (V2 NPP). requirements for the optimization process are given in the mentioned Code No.12 of Ministry of Health. Code 12 stipulates the technical and organizational requirements for proving the Rational Achievable Level (RAL) of radiation protection. This level can be proved by means of the comparison of the dose distribution to the costs of protection. An example of two figures of dose constraints is: collective dose 20 man mSv for the specific task; individual exposure 1 mSv per day. The values of the financial equivalents of personal exposure - so called the alpha coefficients - are used for the calculation of the benefit of proposed measures. Impact of legislative changes into Bohunice NPP and optimization process are presented. Apparently the new law and the associate code created a base of transparent and understandable policy of radiation protection and optimization in Slovak Republic. The radiation protection legislative was implemented into the praxis and persons became familiar with it. Defining clear and unambiguous terms facilitated the communication between users and the regulatory body - State Health Institute. Optimization was generally accepted by the workers and managers and began to be a part of safety culture of operation at nuclear power plants. (authors)

The evolution of the fuel cycle in the Dukovany NPP

Energy Technology Data Exchange (ETDEWEB)

Bajgl, J [Jaderna Elektrarna, Dukovany (Czech Republic)

1994-12-31

The ten-year operational experience of four WWER-440 units in Dukovany NPP with a total number of 35 cycles is outlined. The strategy of fuel reloading has been changed from out-in schemes to low-leakage patterns. The linear pin power limitation will be introduced. The main physical limits and conditions for the NPP operation are listed. The main goal is to go to a full 4-year fuel cycle in which the burnup will be about 40 Mwd/kg U. 6 tabs.

Co-ordinated research programme on benchmark study for the seismic analysis and testing of WWER-type nuclear power plants. V. 4D. Paks NPP: Analysis and testing. Working material

International Nuclear Information System (INIS)

1996-01-01

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 seismic margin assessment and earthquake experience based methods for WWER-440/213 type NPPs; structural analysis and site inspection for site requalification; structural response of Paks NPP reactor building; analysis and testing of model worm type tanks on shaking table; vibration test of a worm tank model; evaluation of potential hazard for operating WWER control rods under seismic excitation

Estimation of the radiation risks for population in the process of the BN-600 power unit operation at the Beloyarsk NPP

International Nuclear Information System (INIS)

Koltik, I.I.; Oshkanov, N.N.

2005-01-01

Dose burdens on the population are the main criterion in estimating the radiological risks during NPP operation. Results of analysis of annual dose burdens on the population in the period of the BN-600 unit operation are presented. Data on individual and collective doses due to gas-aerosol and liquid effluents of radionuclides from the BN-600 unit on critical groups of population are presented. Data on collective doses due to other types of reactors are provided. It is shown that the risks stemming from the BN type reactors are approximately 2 orderers below the risks of channel-type and WWER-reactors [ru

Health risk in nuclear power plants

International Nuclear Information System (INIS)

Bliznakov, V.

1997-01-01

Worked out are the health risk indices for NPP personnel that could be used in normal operation and in case of accident. These indices concern temporary incapacity for work, invalidity, lethality, cancer, etc. Risk estimation is based on produced energy in NPP or on the collective dose of personnel exposure. Assessed are the specific risk values for NPP ''Kozloduy'', which show that the risk in normal operation is significantly low (of the order of 2.3 ./. 7.2 x 10 -4 for invalidity, lethality and cancer). Health risk indices can be used when comparing various alternative energy sources, as well as for determination of the power strategy of a country. (author)

Second report of the Republic of Bulgaria on the fulfilment of the obligations on the Convention on nuclear safety

International Nuclear Information System (INIS)

Committee on the use of atomic energy for peaceful purposes

2003-01-01

The document presents article 17 'NPP siting', article 18 'NPP design and construction' , and article 19 'NPP operation' from the Second National Report. For the siting the issues concerning the new circumstances in the studies of the sites 'Kozloduy' and 'Belene' are presented. A brief review of the corresponding article in the First National report is made. No changes are made in the legislation concerning design and construction for this period. Under article 19 the following topics are presented: Permission for commissioning; Limits and conditions for the operation; Operational documentation; Emergency procedures; Maintenance; Reporting of the events and analysis of the operational experience; Generation and treatment of radioactive waste

Enhancing NPP Safety Through an Effective Dependability Management

Energy Technology Data Exchange (ETDEWEB)

Vieru, G., E-mail: g_vieru@yahoo.com [AREN, Bucharest (Romania)

2014-10-15

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)

NPP Temelin instrumentation and control system upgrade and verification

International Nuclear Information System (INIS)

Ubra, O.; Petrlik, J.

1998-01-01

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)

Scheme of higher-density storage of spent nuclear fuel in Chernobyl NPP interim storage facility no. 1

International Nuclear Information System (INIS)

Britan, P.M.

2008-01-01

On 29. March 2000 the Cabinet of Ministers of Ukraine issued a decree prescribing that the last operating unit of Chernobyl NPP be shut down before its design lifetime expiry. In accordance with the Contract concluded on 14 June 1999 between the National Energy-generating Company 'Energoatom' and the Consortium of Framatome, Campenon Bernard-SGE and Bouygues, in order to store the spent ChNPP fuel a new interim dry storage facility (ISF-2) for spent ChNPP fuel would be built. Currently the spent nuclear fuel (spent fuel assemblies - SFAs) is stored in reactor cooling pools and in the reactors on Units 1, 2, 3, as well as in the wet Interim Storage Facility (ISF-1). Taking into account the expected delay with the commissioning of ISF-2, and in connection with the scheduled activities to build the New Safe Confinement (including the taking-down of the existing ventilation stack of ChNPP Units 3 and 4) and the expiry of the design operation life of Units 1 and 2, it is expedient to remove the nuclear fuel from Units 1, 2 and 3. This is essential to improve nuclear safety and ensure that the schedule of construction of the New Safe Confinement is met. The design capacity of ISF-1 (17 800 SFAs) is insufficient to store all SFAs (21 284) currently on ChNPP. A technically feasible option that has been applied on other RBMK plants is denser storage of spent nuclear fuel in the cooling ponds of the existing ISF-1. The purpose of the proposed modifications is to introduce changes to the ISF-1 design supported by necessary justifications required by the Ukrainian codes with the objective of enabling the storage of additional SFAs in the existing storage space (cooling pools). The need for the modification is caused by the requirement to remove nuclear fuel from the ChNPP units as soon as possible, before the work begins to decommission these units, as well as to create safe conditions for the construction of the New Safe Confinement over the existing Shelter Unit. (author)

SAT for NPP personnel training in USA

International Nuclear Information System (INIS)

Spinney, R.

1995-01-01

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

Considerations related to Cernavoda NPP lifetime management

International Nuclear Information System (INIS)

Cojan, Mihail

2007-01-01

Cernavoda NPP, the first CANDU in Europe, is one of the original CANDU 6 plants and the first CANDU 6 producing over 706 MWe. While the first series of CANDU 6 plants (which entered service in the early 1980 s) have now reached the 2/3 of their 30 years design life, the Cernavoda NPP was put into service on the 2nd December 1996. After 10 years of operation the Plant Life Management (PLiM) Program for Cernavoda should be an increasingly important program to Utility ('CNE - Prod') in order to protect the investment and the continued success of plant operation. The goal of the paper is to present some considerations related to Cernavoda NPP lifetime management. The Plant Life Management Program, known as PLiM Program is concerned with the analysis of technical limits of the safe operation - from the point of view of nuclear safety - in NPP units, aiming at attaining the planned 30 years life duration and its extension to 40 or even 50 years of safe and economical operation. For the CANDU reactors the so-called PLiM and PLEX Programs are just applied. These are applied research programs that approach with priority the current practices for assessing the capability of safe operation within the limits of nuclear safety (fitness-for-service assessment). These programs also approach inspection, monitoring are prevention of degrading due to the ageing of critical systems, structures and components (CSSCs). As each nuclear plant is somewhat different in its components and systems, materials composition, procurement, construction, and operational history, directed research and development programs into materials behavior, monitoring techniques, and methods to mitigate ageing are required to support the lifetime management. Over the past 6 years, INR Pitesti (Institute for Nuclear Research - Romania) has been working on R and D Programs to support a comprehensive and integrated Cernavoda NPP Life Management Program (PLiM) that will see the Cernavoda NPP successfully and

WIMS-IST/DRAGON-IST side-step calculation of reactivity device and structural material incremental cross sections for Wolsong NPP Unit 1

International Nuclear Information System (INIS)

Dahmani, M.; McArthur, R.; Kim, B.G.; Kim, S.M.; Seo, H.-B.

2008-01-01

This paper describes the calculation of two-group incremental cross sections for all of the reactivity devices and incore structural materials for an RFSP-IST full-core model of Wolsong NPP Unit 1, in support of the conversion of the reference plant model to two energy groups. This is of particular interest since the calculation used the new standard 'side-step' approach, which is a three-dimensional supercell method that employs the Industry Standard Toolset (IST) codes DRAGON-IST and WIMS-IST with the ENDF/B-VI nuclear data library. In this technique, the macroscopic cross sections for the fuel regions and the device material specifications are first generated using the lattice code WIMS-IST with 89 energy groups. DRAGON-IST then uses this data with a standard supercell modelling approach for the three-dimensional calculations. Incremental cross sections are calculated for the stainless-steel adjuster rods (SS-ADJ), the liquid zone control units (LZCU), the shutoff rods (SOR), the mechanical control absorbers (MCA) and various structural materials, such as guide tubes, springs, locators, brackets, adjuster cables and support bars and the moderator inlet nozzle deflectors. Isotopic compositions of the Zircaloy-2, stainless steel and Inconel X-750 alloys in these items are derived from Wolsong NPP Unit 1 history dockets. Their geometrical layouts are based on applicable design drawings. Mid-burnup fuel with no moderator poison was assumed. The incremental cross sections and key aspects of the modelling are summarized in this paper. (author)

Cernavoda NPP Unit 2 and Romanian nuclear industry

International Nuclear Information System (INIS)

Mocanu Horia

2001-01-01

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

Practical experience with the leaky-fuel monitoring at Bohunice NPP

International Nuclear Information System (INIS)

Kacmar, M.; Cizek, J.

2001-01-01

The first part of this paper describes practical experience with the fuel monitoring in operating reactors from point of view possible leakages. Summarized in the paper are numbers leaky fuel assemblies both for NPP and for particular units. Some failure causes are discussed for operational conditions of Bohunice NPP. In the second part of paper critical power ramps on hot fuel rod of leaky fuel assemblies are analysed to eliminate failures from PCI. The main aim of the paper is the need to understand the mechanism and causes of failures (Authors)

R and D status for NPP life management in Korea

Energy Technology Data Exchange (ETDEWEB)

Kim, Tae Ryong [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

2009-04-15

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.

R and D status for NPP life management in Korea

International Nuclear Information System (INIS)

Kim, Tae Ryong

2009-01-01

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.

Modernization of tritium in air monitoring system for CANDU type NPP

International Nuclear Information System (INIS)

Purghel, L.; Iancu, R.; Popescu, M.

2009-01-01

Nuclear energy provides at present one third of Europe's electricity with nearly no greenhouse-gas emissions. Sustained efforts are now being conducted to harmonize regulations all over Europe through WENRA and to converge on technical nuclear safety practices within the TSO network ETSON (European Technical Safety Organizations Network). In order to achieve this goals of safety function, IFIN-HH together with CITON developed a new solution to improve the Tritium Monitoring System (TMS) of Cernavoda NPP and the new generation of CANDU type reactors, using Tritium in air Intelligent Monitors (TIM) developed and patented by IFIN-HH. The paper presents a comparative analysis between the technical characteristics of traditional solutions implemented in CANDU type NPP, particularly in Cernavoda NPP Unit 2 and the newly proposed solution. (authors)

Seismic evaluation of existing nuclear facilities. Proceedings of the SMiRT-14 post conference seminar no. 16

International Nuclear Information System (INIS)

2001-03-01

Since 1992 the IAEA has been assisting Member States to develop NPP specific guidelines used in post-construction seismic safety reevaluation. Technical guidelines were developed with the aim to establish a general framework within which a seismic reevaluation of an operating NPP can be carried out. These guidelines will form the basis of an IAEA Safety Report on seismic evaluation of the existing nuclear facilities. Forty papers from 26 countries were presented. Most of the papers reviewed activities in the field of seismic reevaluation and upgrading of existing plants carried out in recent years. This is essential for the IAEA in the development of a unified approach to the seismic reevaluation of existing facilities applicable to WWERs, CANDU, PWRs, etc. A number of papers deal with the CRP benchmark study for the seismic analysis and testing of WWER type NPPs organized by the IAEA (1993-1997). The focal activities of the CRP were benchmarking exercises, applying similar methodology both for Paks NPP and Kozloduy NPP Unit 5 to test the NPP (mainly reactor building) using blast loading generated by a series of artificially generated underground explosions. This work highlighted the reliability of the available numerical tools, the need for further research, and a general judgement on the best compromise between experimental and numerical tools in the seismic reevaluation process. The final results of the CRP were presented in IAEA-TECDOC-1176

Seismic evaluation of existing nuclear facilities. Proceedings of the SMiRT-14 post conference seminar no. 16

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

Since 1992 the IAEA has been assisting Member States to develop NPP specific guidelines used in post-construction seismic safety reevaluation. Technical guidelines were developed with the aim to establish a general framework within which a seismic reevaluation of an operating NPP can be carried out. These guidelines will form the basis of an IAEA Safety Report on seismic evaluation of the existing nuclear facilities. Forty papers from 26 countries were presented. Most of the papers reviewed activities in the field of seismic reevaluation and upgrading of existing plants carried out in recent years. This is essential for the IAEA in the development of a unified approach to the seismic reevaluation of existing facilities applicable to WWERs, CANDU, PWRs, etc. A number of papers deal with the CRP benchmark study for the seismic analysis and testing of WWER type NPPs organized by the IAEA (1993-1997). The focal activities of the CRP were benchmarking exercises, applying similar methodology both for Paks NPP and Kozloduy NPP Unit 5 to test the NPP (mainly reactor building) using blast loading generated by a series of artificially generated underground explosions. This work highlighted the reliability of the available numerical tools, the need for further research, and a general judgement on the best compromise between experimental and numerical tools in the seismic reevaluation process. The final results of the CRP were presented in IAEA-TECDOC-1176.

Bases of updating of nuclear safety regulations for NPP in Romania

International Nuclear Information System (INIS)

Biro, Lucian; Serbanescu, Dan

1999-01-01

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)

NPOESS Preparatory Project (NPP) Science Overview

Science.gov (United States)

Butler, James J.

2011-01-01

NPP Instruments are: (1) well understood thanks to instrument comprehensive test, characterization and calibration programs. (2) Government team ready for October 25 launch followed by instrument activation and Intensive Calibration/Validation (ICV). NPP Data Products preliminary work includes: (1) JPSS Center for Satellite Applications and Research (STAR) team ready to support NPP ICV and operational data products. (2) NASA NPP science team ready to support NPP ICV and EOS data continuity.

Seismic functional qualification of active mechanical and electrical components based on shaking table testing

International Nuclear Information System (INIS)

Jurukovski, D.

1999-01-01

The seismic testing for qualification of one sample of the NPP Kozloduy Control Panel type YKTC was carried out under Research Contract no: 8008/Rl, entitled: 'Seismic Functional Qualification of Active Mechanical and Electrical Components Based on Shaking Table Testing'. The tested specimen was selected by the Kozloduy NPP staff, Section 'TIA-2' (Technical Instrumentation and Automatics), however the seismic input parameters were selected by the NPP Kozloduy staff, Section HTS and SC (Hydro-Technical Systems and Engineering Structures). The applied methodology was developed by the Institute of Earthquake Engineering and Engineering Seismology staff. This report presents all relevant items related to the selected specimen seismic testing for seismic qualification such as: description of the tested specimen, mounting conditions on the shaking table, selection of seismic input parameters and creation of seismic excitations, description of the testing equipment, explanation of the applied methodology, 'on line' and 'off line' monitoring of the tested specimen, functioning capabilities, discussion of the results and their presentation and finally conclusions and recommendations. In this partial project report, two items are presented. The first item presents a review of the existing and used regulations for performing of the seismic and vibratory withstand testing of electro-mechanical equipment. The selection is made based on MEA, IEEE, IEC and former Soviet Union regulations. The second item presents the abstracts of all the tests performed at the Institute of Earthquake Engineering and Engineering Seismology in Skopje. The selected regulations, the experience of the Institute that has been gathered for the last seventeen years and some theoretical and experimental research will be the basis for further investigations for development of a synthesised methodology for seismic qualification of differently categorized equipment for nuclear power plants

Grassland Npp Monitoring Based on Multi-Source Remote Sensing Data Fusion

Science.gov (United States)

Cai, Y. R.; Zheng, J. H.; Du, M. J.; Mu, C.; Peng, J.

2018-04-01

Vegetation is an important part of the terrestrial ecosystem. It plays an important role in the energy and material exchange of the ground-atmosphere system and is a key part of the global carbon cycle process.Climate change has an important influence on the carbon cycle of terrestrial ecosystems. Net Primary Productivity (Net Primary Productivity)is an important parameter for evaluating global terrestrial ecosystems. For the Xinjiang region, the study of grassland NPP has gradually become a hot issue in the ecological environment.Increasing the estimation accuracy of NPP is of great significance to the development of the ecosystem in Xinjiang. Based on the third-generation GIMMS AVHRR NDVI global vegetation dataset and the MODIS NDVI (MOD13A3) collected each month by the United States Atmospheric and Oceanic Administration (NOAA),combining the advantages of different remotely sensed datasets, this paper obtained the maximum synthesis fusion for New normalized vegetation index (NDVI) time series in 2006-2015.Analysis of Net Primary Productivity of Grassland Vegetation in Xinjiang Using Improved CASA Model The method described in this article proves the feasibility of applying data processing, and the accuracy of the NPP calculation using the fusion processed NDVI has been greatly improved. The results show that: (1) The NPP calculated from the new normalized vegetation index (NDVI) obtained from the fusion of GIMMS AVHRR NDVI and MODIS NDVI is significantly higher than the NPP calculated from these two raw data; (2) The grassland NPP in Xinjiang Interannual changes show an overall increase trend; interannual changes in NPP have a certain relationship with precipitation.

Enhancement of equipment services for Kozloduy NPP

International Nuclear Information System (INIS)

Schultz, Christophe

2013-01-01

Conclusion After 5 years of maintenance services, KNPP and AREVA have continuously intensified their partnership Close cooperation between KNPP, AREVA Local Office Engineers and OEM experts Involvement of sophisticated tools for diagnostics and condition monitoring Performance of engineering services and obsolescence evaluation Possibilities to perform equipment modernization of Electrical and IC equipment in future

Analysis of NPP protection structure reliability under impact of a falling aircraft

International Nuclear Information System (INIS)

Shul'man, G.S.

1996-01-01

Methodology for evaluation of NPP protection structure reliability by impact of aircraft fall down is considered. The methodology is base on the probabilistic analysis of all potential events. The problem is solved in three stages: determination of loads on structural units, calculation of local reliability of protection structures by assigned loads and estimation of the structure reliability. The methodology proposed may be applied at the NPP design stage and by determination of reliability of already available structures

NPP life management (abstracts)

International Nuclear Information System (INIS)

Litvinskij, L.L.; Barbashev, S.V.

2002-01-01

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

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)

Deneanu, Cornel; Popa Nemoiu, Dragos; Nica, Dana; Bucur, Cosmin

2007-01-01

The continuous monitoring of gas mixture concentrations (deuterium/ hydrogen/oxygen/nitrogen) accumulated in 'Moderator Cover Gas', 'Liquid Control Zone' and 'Heat Transport D 2 O 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

RELAP5/MOD3.2 investigation of reactor vessel YR line capabilities for primary side depressurization during the TLFW in VVER1000/V320

International Nuclear Information System (INIS)

Gencheva, Rositsa V.; Stefanova, Antoaneta E.; Groudev, Pavlin P.

2005-01-01

During the development of Symptom Based Emergency Operating Procedures (SB-EOPs) for VVER-1000/V320 units at Kozloduy Nuclear Power Plant (NPP), a number of analyses have been performed using the RELAP5/MOD3.2 computer code. One of them is 'Investigation of reactor vessel YR line capabilities for primary side depressurization during the Total Loss of Feed Water (TLFW)'. The main purpose of these calculations is to evaluate the capabilities of YR line located at the top of the reactor vessel for primary side depressurization to the set point of High Pressure Injection System (HPIS) actuation and the abilities for successful core cooling after Feed and Bleed procedure initiation. For the purpose of this, operator action with 'Reactor vessel off-gas valve - 0.032 m' opening has been investigated. RELAP5/MOD3.2 computer code has been used to simulate the TLFW transient in VVER-1000 NPP model. This model was developed at Institute for Nuclear Research and Nuclear Energy - Bulgarian Academy of Sciences (INRNE-BAS), Sofia, for analyses of operational occurrences, abnormal events, and design basis scenarios. The model provides a significant analytical capability for the specialists working in the field of NPP safety

Investigation of station blackout scenario in VVER440/v230 with RELAP5 computer code

Energy Technology Data Exchange (ETDEWEB)

Gencheva, Rositsa Veselinova, E-mail: roseh@mail.bg; Stefanova, Antoaneta Emilova, E-mail: antoanet@inrne.bas.bg; Groudev, Pavlin Petkov, E-mail: pavlinpg@inrne.bas.bg

2015-12-15

Highlights: • We have modeled SBO in VVER440. • RELAP5/MOD3 computer code has been used. • Base case calculation has been done. • Fail case calculation has been done. • Operator and alternative operator actions have been investigated. - Abstract: During the development of symptom-based emergency operating procedures (SB-EOPs) for VVER440/v230 units at Kozloduy Nuclear Power Plant (NPP) a number of analyses have been performed using the RELAP5/MOD3 (Carlson et al., 1990). Some of them investigate the response of VVER440/v230 during the station blackout (SBO). The main purpose of the analyses presented in this paper is to identify the behavior of important VVER440 parameters in case of total station blackout. The RELAP5/MOD3 has been used to simulate the SBO in VVER440 NPP model (Fletcher and Schultz, 1995). This model was developed at the Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences (INRNE-BAS), Sofia, for analyses of operational occurrences, abnormal events and design based scenarios. The model provides a significant analytical capability for specialists working in the field of NPP safety.

NPP Evaluation, backfitting and life extension. An engineering viewpoint

Energy Technology Data Exchange (ETDEWEB)

Gonzalez Lopez, A [Empresarios Agrupados, A.I.E., Madrid (Spain)

1993-12-15

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)

NPP Evaluation, backfitting and life extension. An engineering viewpoint

International Nuclear Information System (INIS)

Gonzalez Lopez, A.

1993-01-01

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)

The radiation factor 'hot particles': origin, methods of investigation, characterization and risk factors

International Nuclear Information System (INIS)

Bonchev, Ts.; Vapirev, E.; Yanev, Y.

1993-01-01

The problem of hot particles (HP) is reviewed chronologically following published data. The term appeared in the 50-s when HP have been found in fallout as a result of nuclear explosions in the atmosphere. After the Chernobyl accident there is a growing interest in HP. In 1986 HP have been discovered in American nuclear power plants (NPP) and in 1992 some have been found at Kozloduy NPP in Bulgaria as well. Detection and collection methods and different approaches for HP investigation are discussed. The direct and indirect risks from HP are described. It is concluded that the problem deserves further investigation and the discovery of HP inside NPP is of special interest

The radiation factor `hot particles`: origin, methods of investigation, characterization and risk factors

Energy Technology Data Exchange (ETDEWEB)

Bonchev, Ts; Vapirev, E; Yanev, Y

1994-12-31

The problem of hot particles (HP) is reviewed chronologically following published data. The term appeared in the 50-s when HP have been found in fallout as a result of nuclear explosions in the atmosphere. After the Chernobyl accident there is a growing interest in HP. In 1986 HP have been discovered in American nuclear power plants (NPP) and in 1992 some have been found at Kozloduy NPP in Bulgaria as well. Detection and collection methods and different approaches for HP investigation are discussed. The direct and indirect risks from HP are described. It is concluded that the problem deserves further investigation and the discovery of HP inside NPP is of special interest.

Implementation of the II. Stage decommissioning of A1 NPP

International Nuclear Information System (INIS)

Ficher, T.

2015-01-01

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)

Dynamic model for tritium build-up at NPP with RBMK type reactors and its enviromental beraviour

International Nuclear Information System (INIS)

Badyaev, V.V.; Egorov, Yu.A.; Ivanov, E.A.; Stegachev, G.F.; Tolstykh, V.D.

1982-01-01

A model of tritium production dynamics for a high power NPP with RBMK type reactors is proposed and investigated. The main ''skeleton'' model structure for forecasting tritium buildup at a NPP and its exchange with the environment has been singled out at a heuristic level. Decomposition and layout of the units have been performed by global functional relations of the investigated objects (NPP and environment). the model accounts for only oxidized tritium forms. Water exchange between the NPP subsystems and environment is the main mechanism for tritium migration. The model does not account for scheduled periodic maintenance work effects, presence of stagnant zones in the station circuits, fuel burn-up, etc. The parametric identification method applied in the model makes the model adaptable to particular situations and considered systems of the NPP and environment. Completing the model with necessary and sufficient experimental data one can pass to certain forecasting problems and to NPP control as a tritium source in the environment

Experience in NPP operation and prospects of nuclear power development in France

International Nuclear Information System (INIS)

Lekler, Zh.

1986-01-01

Main results and perspectives of nuclear power development in France are analysed. Data characterizing operation of NPPs with PWR reactors in France and leading capitalist countries are given. Problems related to the organization of works on control of NPP operation and its maintenance are discussed. Power utilization factor for french power units amounted to 75% in 1984. NPP share of all electric power generated in the country constituted 59%. Emergency reactor shut-downs took 5% of calendar time in 1984

The trends in the social opinion for the nuclear energy development in Bulgaria during the last five years

International Nuclear Information System (INIS)

Nanov, D.

2001-01-01

The sociological investigations in Bulgaria about the development of nuclear energy show that generally most of the people understand the importance of the nuclear power production in the country and are inclined to support it if the necessary safety level is guaranteed. 53.2% are against the early shutdown of the Kozloduy NPP units 1-4. Only 9.6% think that the authorities give adequate information about the atomic energy production. 34.6% are of the opinion that the actions of the authorities are unclear and that the population is not informed enough about them. A common opinion is that the public relations should be extended and the people need more information in the field of nuclear energy

Key features of MIR.1200 (AES-2006) design and current stage of Leningrad NPP-2 construction

International Nuclear Information System (INIS)

Ivkov, Igor

2010-01-01

MIR.1200/AES-2006 is an abbreviated name of the evolving NPP design developed on the basis of the VVER-1000 Russian design with gross operation life of 480 reactor-years. This design is being implemented in four Units of Leningrad NPP-2 (LNPP-2. The AES-91/99 was used as reference during development of the AES-2006 design for LNPP-2; this design was implemented in two Units of Tianwan NPP (China). The main technical features of the MIR.1200/AES-2006 design include a double containment, four trains of active safety systems (4x100%, 4x50%), and special engineering measures for BDBA management (core catcher, H2 PARs, PHRS) based mainly on passive principles. The containment is described in detail, the main features in comparison with the reference NPP are outlined, the design layout principles are highlighted, the safety system structure and parameters are described. Attention is paid to the BDBA management system, hydrogen removal system, core catcher, and PHRS-SG and C-PHRS. (P.A.)

New generation main control room of enhanced safety NPP with MKER reactor

International Nuclear Information System (INIS)

Golovanev, V.E.; Gorelov, A.I.; Proshin, V.A.

1994-01-01

Russia is planning to begin the gradual substitution RMBK NPP units, whose resources were worked out itself, to NPP units with a 800 MW multiloop boiling water power reactor (MKER-800) enhanced safety at next ten-year period. Main drawbacks of RBMK Reactor were completely removed in design of MKER-800 reactor. Moreover some special decisions were made to give MKER-800 self-safety properties. The proposed design of the MKER-800 enhanced safety reactor is not only fully free from the drawbacks of the RBMK reactors, but also show a number of advantages of channel-type reactors. This Paper presents some preliminary proposals of MCR Design, that developed Research and Development Institute of Power Energy (RDIPE). 6 refs, 2 figs

Fusion of eastern and western technology in VVER 1000 NPP upgrade

International Nuclear Information System (INIS)

Ubra, O.; Fleischhans, J.; Kveton, M.

1997-01-01

An extensive modernization program upgrading two units of VVER 1000 type of the Czech nuclear power plant (NPP) Temelin to meet the latest international standards is presented. The program is based primarily on combination of eastern and western technology and it has been implemented during plant construction. The NPP Temelin was originally designed according to the standards of the former Soviet Union. After a series of reviews in the 1990s, a decision was made by the Temelin management of upgrade the design of the plant, including the supply of fuel and instrumentation and control system by a western company. The adoption of western technology and practices has helped to solve a large number of IAEA safety issues related to design and operation of VVER 1000 NPP. Details on the current Temelin design and other related safety matters are presented

Construction of Site Risk Model using Individual Unit Risk Model in a NPP Site

Energy Technology Data Exchange (ETDEWEB)

Lim, Ho Gon; Han, Sang Hoon [KAERI, Daejeon (Korea, Republic of)

2016-05-15

Since Fukushima accident, strong needs to estimate site risk has been increased to identify the possibility of re-occurrence of such a tremendous disaster and prevent such a disaster. Especially, in a site which has large fleet of nuclear power plants, reliable site risk assessment is very emergent to confirm the safety. In Korea, there are several nuclear power plant site which have more than 6 NPPs. In general, risk model of a NPP in terms of PSA is very complicated and furthermore, it is expected that the site risk model is more complex than that. In this paper, the method for constructing site risk model is proposed by using individual unit risk model. Procedure for the development of site damage (risk) model was proposed in the present paper. Since the site damage model is complicated in the sense of the scale of the system and dependency of the components of the system, conventional method may not be applicable in many side of the problem.

New system technologies implemented at Kozloduy 3 and 4 (WWER 440-230) for containment leakage and H2 control in severe accident situations - Design, qualification, installation, commissioning

International Nuclear Information System (INIS)

Feuerbach, R.; Eckardt, B.; Kastner, B.

2005-01-01

In order to reduce the residual risk associated with hypothetical severe nuclear accidents, systems and components for filtered containment venting and H 2 reduction were developed. During severe accident scenarios large quantities of hydrogen and radioactive material may be released into the containment atmosphere within a short period of time. In the event of internal over pressurization due to hypothetical severe accident sequences a pressure barrier system has to be created to confine the activity in the containment. Unavoidable releases of activity to the environment have to be minimized to a great extent as possible. Research into the hypothetical event of core melt accidents has continued and new accident mitigation technologies have been developed. Decisions have been taken to implement these new mitigation measures in operating nuclear power plants to mitigate severe accidents consequences. In order to prevent loss of containment integrity as a result of over pressurization, nuclear power plants in the Federal Republic of Germany as well as in most other European countries have been or will be back-fitted with systems for filtered venting of the containment atmosphere and systems for H 2 -control. Similar technologies for containment venting system and H 2 control have been now implemented in the first WWER 440-230 units of Kozloduy 3 and 4. Following OECD recommendations sever accident situations were analyzed and a design of countermeasures have been performed. Main goal of the developed countermeasures was to overcome the WWER 440-230 containment design specifics like, leakage rate behavior, limited available containment volume combined with the feature of high availability of electrical supply at multiple plant sites. Further more the design of counter measures considers the common use for Kozloduy unit 3 and 4. The analysis of postulated severs accident situation - without countermeasures - showed significant increase of H 2 /O 2 concentration in the

Solid radioactive waste processing facility of the NPP Leningrad

International Nuclear Information System (INIS)

Weichard, Swetlana

2008-01-01

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.

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

International Nuclear Information System (INIS)

Caeny, P.; Chyly, M.; Suchon, D.; Smejkalova, E.; Fabova, V.; Mancikova, M.; Muller, P.

2009-01-01

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)

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

International Nuclear Information System (INIS)

Caeny, P.; Chyly, M.; Suchon, D.; Smejkalova, E.; Fabova, V.; Mancikova, M.; Muller, P.

2008-01-01

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)

Introducing advanced ISI requirements at Paks NPP for supporting the LTO

International Nuclear Information System (INIS)

Trampus, P.; Ratkai, S.

2012-01-01

The four VVER-440 model 213 units in operation at Paks NPP, Hungary, are facing to approach their licensed term of operation, which is 30 years. To extend the safe operation of the units beyond the original licensed term by additional 20 years belongs to the highest priorities of the owners/operator of MVM Paks NPP. According to the nuclear legislation, a formal license renewal application for the extended period has to be submitted to the Hungarian Atomic Energy Authority. A significant feature of the license renewal process is the demonstration of the effectiveness of the currently applied ageing management program. ISI is an essential part of the ageing management program thus the adequate ISI techniques and the tailor made requirements have to be incorporated in it. To cope with the expectations originating from the LTO at Paks NPP, it was decided to replace the original Soviet based ISI system by the widely applied ASME BPVC Section XI requirements. Additionally, in 2011 a new nuclear regulation was issued in Hungary, in which the ISI requirements have also been changed. This paper intends to present the entire structure of the new Hungarian regulation related to the ISI but mainly focusing on the deviation to the ASME Section XI with the perspective of the licence renewal. (author)

Construction of Belene NPP in Bulgaria

International Nuclear Information System (INIS)

JSC Atomstroyexport

2010-01-01

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

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)

Branzeu, N.; Necula, D.; Badea, M.; Teodorescu, D.; Peteu, M.

2006-01-01

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)

In-house developed methodologies and tools for decommissioning projects

International Nuclear Information System (INIS)

Detilleux, Michel; Centner, Baudouin

2007-01-01

The paper describes different methodologies and tools developed in-house by Tractebel Engineering to facilitate the engineering works to be carried out especially in the frame of decommissioning projects. Three examples of tools with their corresponding results are presented: - The LLWAA-DECOM code, a software developed for the radiological characterization of contaminated systems and equipment. The code constitutes a specific module of more general software that was originally developed to characterize radioactive waste streams in order to be able to declare the radiological inventory of critical nuclides, in particular difficult-to-measure radionuclides, to the Authorities. In the case of LLWAA-DECOM, deposited activities inside contaminated equipment (piping, tanks, heat exchangers...) and scaling factors between nuclides, at any given time of the decommissioning time schedule, are calculated on the basis of physical characteristics of the systems and of operational parameters of the nuclear power plant. This methodology was applied to assess decommissioning costs of Belgian NPPs, to characterize the primary system of Trino NPP in Italy, to characterize the equipment of miscellaneous circuits of Ignalina NPP and of Kozloduy unit 1 and, to calculate remaining dose rates around equipment in the frame of the preparation of decommissioning activities; - The VISIMODELLER tool, a user friendly CAD interface developed to ease the introduction of lay-out areas in a software named VISIPLAN. VISIPLAN is a 3D dose rate assessment tool for ALARA work planning, developed by the Belgian Nuclear Research Centre SCK.CEN. Both softwares were used for projects such as the steam generators replacements in Belgian NPPs or the preparation of the decommissioning of units 1 and 2 of Kozloduy NPP; - The DBS software, a software developed to manage the different kinds of activities that are part of the general time schedule of a decommissioning project. For each activity, when relevant

On some problems concerning the national emergency planning

Energy Technology Data Exchange (ETDEWEB)

Angelov, V [Civil Defence Administration, Sofia (Bulgaria); Bonchev, Ts [Sofia Univ. (Bulgaria). Fizicheski Fakultet; Andonov, S [Civil Defence Administration, Sofia (Bulgaria); Semova, T [Sofia Univ. (Bulgaria). Fizicheski Fakultet; Ganchev, N [Committee on the Use of Atomic Energy for Peaceful Purposes, Sofia (Bulgaria); Georgiev, V [Energoproekt, Sofia (Bulgaria)

1996-12-31

The basic principles of national emergency planning and preparedness in case of severe nuclear accident are discussed. Recommendations concerning the participating authorities in Bulgaria and their cooperation are given. The need to synchronize the plan with the NPP Kozloduy emergency plan is pointed out. The introduction of new legislation outlining the necessity of national emergency planning is stressed. 13 refs.

On some problems concerning the national emergency planning

International Nuclear Information System (INIS)

Angelov, V.; Bonchev, Ts.; Semova, T.; Georgiev, V.

1995-01-01

The basic principles of national emergency planning and preparedness in case of severe nuclear accident are discussed. Recommendations concerning the participating authorities in Bulgaria and their cooperation are given. The need to synchronize the plan with the NPP Kozloduy emergency plan is pointed out. The introduction of new legislation outlining the necessity of national emergency planning is stressed. 13 refs

Operating and mathematical representation of resonances between flow parameters oscillations and structure vibrations of NPP

Energy Technology Data Exchange (ETDEWEB)

Proskuryakov, K.N.; Yang Shan Afshar, E.; Polyakov, N.I. [Nuclear Power Plant Department of Moscow Power Engineering Institute Technical Univ., Moscow (Russian Federation)

2007-07-01

The experimental data that have been obtained from the measurements of noise signals in primary circuit of NPP with reactor of WWER-1000 are presented. The causes of resonant interaction between Eigen-Frequencies of Oscillations of the Coolant Pressure (EFOCP) and structure vibrations are discussed. An application-oriented approach to the problem of identification of abnormal phenomena of thermal-hydraulic parameters is proposed. Logarithmic Decrement {delta} is determined. The bigger damping ratio {zeta} provides bigger {delta} and correspondingly smaller values of Q-factor and amplitude X(t)max. All experimental units intended for NPP severe accident investigation must satisfy to the NPP Q-factor criterion of similarity. (authors)

Operating and mathematical representation of resonances between flow parameters oscillations and structure vibrations of NPP

International Nuclear Information System (INIS)

Proskuryakov, K.N.; Yang Shan Afshar, E.; Polyakov, N.I.

2007-01-01

The experimental data that have been obtained from the measurements of noise signals in primary circuit of NPP with reactor of WWER-1000 are presented. The causes of resonant interaction between Eigen-Frequencies of Oscillations of the Coolant Pressure (EFOCP) and structure vibrations are discussed. An application-oriented approach to the problem of identification of abnormal phenomena of thermal-hydraulic parameters is proposed. Logarithmic Decrement δ is determined. The bigger damping ratio ζ provides bigger δ and correspondingly smaller values of Q-factor and amplitude X(t)max. All experimental units intended for NPP severe accident investigation must satisfy to the NPP Q-factor criterion of similarity. (authors)

Reactor building seismic analysis of a PWR type - NPP

International Nuclear Information System (INIS)

Kakubo, Masao

1983-01-01

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)

NPP service life management

International Nuclear Information System (INIS)

Elagin, Yu.P.

2001-01-01

Problems of NPP service life management and service life prolongation are reviewed. Methods for the prolongation of the French NPP service life are discussed, priority directions of nuclear block service life management in regard to aging in the context of the European program of investigation into the materials aging are identified. Questions of the provision of the 60 years service life of the Mihama 1 block (Japan) and decision of the problem of the control equipment aging in Great Britain are discussed. Situation with the prolongation of licenses on the NPP operation in the USA and Spain is considered [ru

Welding of large-size embelled fittings in NPP construction

International Nuclear Information System (INIS)

Semenov, N.A.; Savinov, O.A.

1988-01-01

Drawbacks of the accepted technology for peoducing embedded fittings are considered. Activities on modernization of the standard ADF-2001 automatic welding machine are described. Results of testing the samples of welded joints performed using the modernized automatic welding machine, and economic effect caused by its introduction at the balakovo NPP second unit construction are presented

RMR. A new portable Reactivity Measuring System installed at NPP Paks