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Nuclear Safety Cooperation

R2.16/93 application of leak Before Break

  • Closed
Benefitting Zone
Eastern Europe / North Asia
€ 209,741.60
EU Contribution
Contracted in 1997
Technical Assistance to the Commonwealth of Independent States


Type of activity

Design Safety



Contracting authority

European Commission

Method of Procurement

Direct Agreement & AV DA


28/07/1997 - 28/12/1998



Project / Budget year

WW9406 Nuclear Safety 1994 / 1994


The objective was to continue and complete TACIS Project 1991-1.2 - Primary Circuit Integrity of VVER-230 Reactors Application of Leak Before Break (LBB) Concept.
During the implementation of that project, extra requirements were identified outside the original scope of work. This follow-on project was dedicated therefore to answer those open questions.
Project R2.16/93 was to undertake provisions to implement LBB concept for Kola NPP especially by:
Assessment of stratification effect in surge line;
Elaboration of the TOR for upgrading the leak detection system;
Elaboration of the TOR for ISI improvement-review and updating of operating procedures;
Updating LBB analysis from Project 1991-1.2;
Verification and justification of LBB concept.
For Novovoronezh NPP Unit 3 and 4 the task was to prove the integrity in normal operating conditions (NOC) based on the results of Project 1991-1.2.
The proof of LBB was to be done for NOC as well as for the safe shut-down/earthquake conditions (SSE) including a concept for additional seismic support if needed. Furthermore, a re-assessment on the proposed support concept was requested when the results of TACIS Project R2.07/94 – Dynamic Calculation of NPP Structures would be available.


The expected results according to the objective were achieved. The questions identified during Project 1991-1.2 have been answered as requested. At the time of the project end, the Beneficiary was already organizing technical meetings for launching the practical implementation of the results at the plants concerned.
The Local Subcontractor received the expected technical basis for applying the LBB concept in practice for the VVER-440/230 units in Kola and Novovoronezh. The commitment to implement the knowledge in practice in the near future is quite obvious. Due to the open nuclear liability issue together with the problems in subcontracting, the actual kick-off took place only in July 1998.
Thus there were practically only five months left for the implementation.