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Improvement of reliability and efficiency of Dukovany Nuclear Power Plant

The Dukovany Nuclear Power Plant (NPP) is one of the Czech Republic’s major power sources. In order to achieve higher efficiency, reliability and operational safety and to extend the power plant’s lifetime, a replacement and refurbishment of several key systems of the power plant has taken place.

ÅF in Czech Republic has been involved in the critical part of the modernization process - replacement and refurbishment of the I&C systems and electrical switchgears. ÅF experts carried out the feasibility study of the modernization program, evaluated the proposed solutions, provided Basic Design and Detailed Design of I&C systems Refurbishment. The power plant remains in full operation throughout the reconstruction.

Implementation of the new I&C system has resulted in lower risk of failure and an increase of the NPP reliability and testability. This has been achieved due to new protection systems that use state of the art computing technology, effective testing and maintenance tools and implementation of superset diagnostic.

There has also been a significant safety improvement achieved especially by an increase of redundancy, implementing the voting logic 2oo3 and reduction of the risk of false signals.

Since the I&C system refurbishment and replacement, there has been significant increase of the power plant’s efficiency. The operation has become easier and there is less need for manual intervention now.

The replacement and refurbishment of the I&C systems was carried out in conformity with the standard IEC 611226.

ÅF experts and NPP staff collaborate closely to reach the main goal of the modernization process: to extend the power plant’s lifetime. A joint effort of the designers, technical supervisors and other nuclear experts has resulted in significant plant’s lifetime extension. The plant’s original lifetime was until 2017. The refurbished power plant now meets the highest quality standards and strict demands in the nuclear sector and can remain in operation until 2040.

ÅF has come up with a strategy that allowed carrying out the modernization with no negative impact on the power plant’s availability. Thanks to this approach there has been no economic loss for the power plant’s owner due to the modernization process. ÅF has also developed advanced control strategies that facilitate optimal control of the power plant’s processes without the need for time-consuming tuning procedures. 

ÅF has also provided services in other areas, e.g. licensed works, fuel handling system and radioactive waste management.

Description of the Project:

The project has been divided into two stages:

Stage 1 was realized between 2002 and 2009 and included the replacement and upgrade of the instrumentation and control systems, which have a substantial influence on the nuclear safety. The scope of the refurbishment includes complete replacement of the original analogue systems with modern digital ones, implementation of a new complex post-accident monitoring system, replacement of sensors and cabling related to the replaced systems, modification of the main and emergency control rooms and general interconnection of the modernized systems with the existing power plant equipment.

Stage 2 included replacement of the control systems of the primary circuit, the turbine and the secondary circuit, including supply of the superset diagnostic and information system (realization in 2007 – 2016).

Services by ÅF:

  • Feasibility study of modernization program and replacement I&C systems
  • Evaluation of the proposed alternatives of replacement I&C systems and power supply alternatives
  • Technical support during tender documentation development
  • Feasibility study of cable routes
  • Development of safety documentation for discussion with State Office for Nuclear Safety
  • Development of documentation for territory permit
  • Study of pressure sensors resistance against pressure wave
  • Classification of the I&C according IEC 61226
  • General erection plan and time schedule
  • Basic Design and Detailed Design of Refurbishment of I&C systems
  • Detail Design of electrical switchgears
  • New turbine algorithm and participation on testing algorithms
  • Safety documentation
  • Participation on FAT, SAT and commissioning of I&C systems
  • Technical supervision of the Design, Installation, Commissioning of I&C systems
  • Licensing works for first operation and after modernization phase
  • Fuel Handling System for Fresh and Spent Fuel Engineering Services
  • Spent Fuel and Rad-Waste Management

Services involved