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Lévai project

In consideration of the results and conclusions of the previous Teller project on March 3, 2009 the Hungarian Parliament approved the governmental proposal for initiating activities to make preparations for constructing new nuclear power plant units. Following the approval MVM Paks NPP Ltd. and MVM Plc. have established the Lévai project. The goal of this project is to carry out all the preparatory work necessary for starting the extension of the current nuclear energy production capacity in Hungary.

Further information.

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Teller project

To ensure reliable and balanced supply of electric power Hungary needs to build new nuclear power plant units. Therefore MVM Plc. and MVM Paks NPP Ltd. initiated the Teller project in 2007. Its objective was to assemble information and data which were seen necessary to underpin decision-making of the Hungarian Parliament concerning its support in principle to preparatory works for constructing new nuclear power plant units.

The Teller project had several Task Groups that focused on the following activities:

1. preparation of a feasibility study
2. preliminarily evaluation of environmental impacts
3. investigation of options for and technical solutions to the storage and future uses of spent fuel and radioactive waste
4. communication planning.

NUBIKI participated in Task Groups a) and b) (through VEIKI Nuclear Engineering Division, as its predecessor)

The results of the Teller project facilitated the approval of the Parliament to initiate preparatory activities for constrcuting new nuclear power plant units. Preparatory work is being carried out within the Lévai project.

Further information

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Plant Lifetime Extension

The original operational service life of the Paks NPP units is 30 years, which would have required termination of plant operation between 2012 and 2017 because the four units were commissioned in the early 80’s.

Based on a preliminary feasibility study the plant expressed its intention to prolong plant lifetime by 20 years. The Parliament has studied the related proposal and gave its approval in principle to realise it.

A systematic lifetime management programme is a precondition for plant lifetime extension. This programme must ensure that safety related plant equipment will operate safely and reliably during the whole period of the planned service life.

NUBIKI has been supporting the lifetime management programme of the plant in several areas:

• by contributing to the development and operation of a dedicated programme on monitoring the effectiveness of maintenance for safety related plant systems and equipment,
• by developing the ADRIA cable database system that supplies input information for ageing management of cables.

Nowadays the ADRIA system serves also as the ultimate tool for the design of cable routes in relation to plant modifications and refurbishment of electrical and I&C systems and components.

Further information.

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Power uprate

The original net electric capacity of the Paks NPP was 440 MWe per unit. A feasibility study has been conducted to support power uprate of each unit.

By making use of the the results of the feasibility study, the plant has increased the power level of the units in two steps:

• first the nominal electric output of the units was raised to 470MWe by improving the efficiency of the secondary circuit,
• then the nominal electric output of each unit was raised to 500MWe by increasing the thermal power level of the reactor.

NUBIKI (through VEIKI Nuclear Engineering Division, its predecessor) supported the power uprate project by performing safety analyses and by making an independent review of the principal licensee application submitted to the regulatory body for approval.

Further information.

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AGNES project 1991-1994

The Hungarian Atomic Energy Authority launched the AGNES project (Advanced General and New Evaluation of Safety) in the early 90’s with the participation of all the major national organisations that were dealing with nuclear safety. The objectives of the AGNES project were[1]:

• to re-evaluate the safety level of the Paks NPP by modern analysis methods and tools in the following areas:
1. re-analysis of design basis accidents
2. severe accident analysis
3. probabilistic safety assessment
4. systems analysis
• to identify and prioritise safety upgrading measures
• to prepare an up-to-date safety analysis report.

The project was performed between 1992 and 1994. The KFKI Atomic Energy Research Institute (today: Hungarian Academy of Sciences, Centre for Energy Research) was in charge of project management. The results of the AGNES project have contributed considerably to improving safety of the Paks NPP up to the level of western nuclear power plants of the same vintage, as well as to set up the conditions for safe operation of the plant.

The scientific staff members of NUBIKI (as employees of the predecessor VEIKI Nuclear Engineering Division) participated in the AGNES project as coordinators and main investigators within the b) and c) subprojects.

Further information in Hungarian

[1] Safety Reassessment of the Paks nuclear power plant, Final report. Prepared in the framework of the AGNES Project. KFKI AEKI/VEIKI Rt./PA Rt./ETV-ERŐTERV Rt. report, May 1995

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SARNET2 Severe accident research network 2

The SARNET network has been set up under the aegis of the Framework Programmes (FP) of the European Commission on research. Two projects have been defined, both coordinated by IRSN (France), in the FP6 (2004-08) and FP7 (2009-13), with the following key objectives:

• Improving knowledge on severe accidents in order to reduce the uncertainties on the pending issues, thereby enhancing plant safety
• Coordinating research resources and expertise available in Europe
• Preserving the research data and disseminating knowledge

NUBIKI has participated in 5 out of the 8 Work Packages (WP) of the second phase of SARNET. The main working areas of NUBIKI were the following

• NUBIKI contributed to WP 4 in order to investigate the ASTEC code capabilities to calculate the effects of accident management measures for VVER-440/213.
• In the COOL work package (WP 5) NUBIKI performed analyses to support the evaluation of coolability of the reactor vessel.
• In WP 6 NUBIKI did calculations with the MEDICIS computer code for the molten corium-concrete interaction
• In WP 7, that was dealing with containment phenomena, NUBIKI performed calculations and analyses of hydrogen mixing and burning experiments.
• The research in WP8 is concerned with the transport of fission products through the RCS and their behaviour in the containment. NUBIKI performed calculations for Phébus FP experiments and examined the usability of the experimental results.

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Targeted Safety (Re-)Assessment

Following the severe accident at the Fukushima Dai-ichi nuclear power plant on 11 March 2011, the Hungarian Atomic Energy Authority passed a resolution to evaluate the risk and safety level of the Paks nuclear power plant within the framework of a Targeted Safety Assessment. The Targeted Safety Assessment was envisaged to estimate the safety margins of the nuclear power plant beyond its design basis with special consideration to the protection against external natural hazards, and to prepare proposals in order to enhance the level of protection.

The Paks power plant has conducted the Targeted Safety Assessment using technical support provided mostly by NUBIKI and the Hungarian Academy of Sciences Centre for Energy Research. The primary tasks of our institute were to review the strategy and means of severe accident management, and to assess the vulnerability of electric power supply, the ultimate heat sink and the containment to extreme external hazards. The major proposals emerged from the results of the assessment included assurance of continuous power supply by means of alternative back-up devices and use of water supplies from alternative resources to ensure removal of residual heat from the reactors shut down as a response to extreme external events. An important lesson learnt from the assessment was the need to apply accident management procedures on multiple plant units at a time if an external event that significantly exceeds the design basis affects several units.

National Report of Hungary on the Targeted Safety Re-assessment

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FSAR Revision

The first Final Safety Analysis Report (FSAR) for the Paks NPP was prepared in 2000. The authority approved this FSAR in 2001 and ordained that it shall be completely revised considering the state of the plant on 31 December 2002 as reference.
A comprehensive programme was drawn up for the revision based on a dedicated Quality Management Plan.

The purpose of FSAR revision was to provide a document establishing the authority-approved reference state of plant operation. The revision was completed in 2004. NUBIKI participated in the preparation of the FSAR by

• developing certain technical subchapters (safety systems, probabilistic safety assessment),
• contributing to the work of the Supercontrol Team that was in charge of technical supervision.

Since then, the FSAR has been updated annually by the plant to always meet the latest regulatory requirements. These updates require considerable resources to be in conformity with the successively changing Nuclear Safety Regulations. Particularly, major efforts have been made to fulfil the requirements published in the appendices of the governmental decrees on safety regulations issued in 2011. A similar task is to be completed by the end of 2013 to reflect changes of safety regulations in 2012. NUBIKI contributes to FSAR updates by working in the technical areas mentioned above.