Summary

At the Mochovce site in Slovakia/>, four units of the Soviet type VVER-440/213 were under construction by the end of the 80's in the former
Czechoslovak/> Republic/>/>. The respective state of completion for units 1 to 4 was 90, 75, 40 and 30 %. After the change in the political situation, construction was practically stopped due to financial shortcomings.

In order to carry out construction of units 1 - 2 with the financial support of European banks for which the European Bank for Reconstruction and Development (EBRD) is acting as a leader, German (Bayernwerk : BAG) and French (Electricite de France : EDF) utilities proposed to their Slovak counterpart, SEP, to create a joint venture. Plans of the support provided by EDF and BAG were not only to support the completeness of the construction of the plant as designed, but also to improve the safety level by implementation of upgrading measures. Proposals to upgrade plant safety are presented in the Safety Improvement Report (SIR).

Before taking any decision, the EBRD had to check whether or not, after implementation of the proposed upgrading measures, the Mochovce units 1 - 2 would be in line with its internal policy on nuclear safety matters:

/>"The standards applied for the construction, management and operation of the plant would have to be fully in line with the fundamental principles set out in IAEA documents. These include, in particular, the document "Basic Safety Principles for Nuclear Power Plants, IAEA Safety Series No 75 - INSAG-3", issued by the Agency's International Nuclear Safety Advisory Group (INSAG), as well as the NUSS ("Nuclear Safety Standards') Codes of Practice, which are a set of recommendations on safety requirements adopted by the Agency's Board of Governors. In addition, at the more detailed level of the various safety systems, the plant safety assessment will be based upon an approach demonstrably equivalent to accepted Western practices ...

... Particular attention would be given to checking the quality of construction and fabrication in already built parts of the plants and for manufactured equipment."

Riskaudit GRS/IPSN International received a contract to perform an independent safety evaluation of the Mochovce project in support of the Slovak Nuclear Regulatory Authority, and to provide the EBRD with technical views of the safety aspect of the project

Within the frame of a contract concluded, under request of the EBRD, between Riskaudit IPSN/GRS International and the CEC, the independent safety evaluation of the Mochovce project which was conducted by IPSN and GRS to support the EBRD, the EC and the Slovak Nuclear Regulatory Authority was based on :

• IPSN and GRS knowledge of VVER's safety deficiencies regarding the application of Western safety standards and practices,
  

• technical documents available for Mochovce,
  

• the Safety Improvement Report (SIR) which presents a set of proposals to upgrade the safety level of Mochovce,
  

• plant walkdowns,
  

• technical discussions.
  

The safety evaluation addressed technical items usually covered in Western Safety Analysis Reports. For each technical item, it was determined whether or not the improved Mochovce situation would respect Western safety requirements and practices, on some topics reference to IAEA safety guides was also considered. If not, investigations were conducted in order to identify whether the deviations were detrimental to safety and if so, recommendations to improve the situation were proposed.

/> />/>Taking into account the existing situation at Mochovce and the implementation of approved measures proposed in the SIR, it can be concluded that, on condition that IPSN-GRS recommendations are correctly and exhaustively dealt by the utility, the construction, management and operation of the plant will be in line with fundamental principles set out in IAEA documents like lNSAG-3 and MUSS Codes of Practice, and with Western safety requirements and practices.

/>In addition waste management, fuel management and transport, and decommissioning were also evaluated. No major discrepancies with Western and international safety practice were found.

Quality already achieved on the site was also examined through an evaluation of existing quality audit reports. No prohibitive problems were found. Recommendations are provided for future activities.

As a general conclusion, it can be stated that, if correctly completed, the Mochovce project will be in keeping with the EBRD policy on nuclear safety matters.

It is important to point out that the implementation of the safety measures shall be realised during the period of the plant construction.

Independent evaluation of current detailed upgrading proposals and safety studies which may lead to additional improvement measures should be organized to support as far as needed the Slovak Nuclear Authority in its tasks. All measures and complete safety demonstration should be provided in the Pre-Operational Safety Report (POSAR) which will constitute the licensing basis to operate the plant.