Beneficiary Organizations Details
State Nuclear Power Safety Inspectorate (VATESI)
http://www.vatesi.lt

Project Aims
The main purpose of the project is to support and increase the competence of VATESI and its TSOs in assessing the BDBA considering the RBMK-1500 characteristics in the following areas:

• accident scenarios regarding behaviour of the defence-in-depth barriers (fuel matrix, fuel rod, main circulation circuit, and reactor confinement);
• behaviour of the spent nuclear fuel in the pools of Ignalina NPP;
• radionuclide transfer and discharge to the environment, including realistic evaluation of source-terms during BDBA.

The adaptation and provision of computer codes, development of engineering handbooks and preparation of updated draft procedures related to the identification of source term for the operation of the VATESI ERC in the case of BDBA at Ignalina NPP, and staff training are foreseen in the project as well.
Project Results
The main result of the project would be increased competence of the Lithuanian nuclear safety authority and strengthened technical expertise resources of VATESI and its TSOs in the area of the beyond design basis accidents for Ignalina NPP.
Expected results:

• A list of the transients that potentially could develop into BDBA with core damage, and important accident phenomena that need to be addressed with accident progression models;
• Analysis of the the in-core, ex-core and containment phenomena for the cases when the total damage of the core is unavoidable and it results in loss of the general structural integrity of the reactor system;
• Experimental measurements in situ of the radionuclide content in the main circulation circuit of the operating reactor and determination of activity ratios of certain isotopes;
• Development with verification, validation (based on data from experimental measurements in situ) of input decks of fuel behaviour, neutronics and thermo-hydraulic computer codes, adapted for RBMK-1500;
• Development of Regulatory Guides on the assessment and management of BDBA for RBMK-1500;
• The improvement of scientific knowledge on specific phenomena and understanding of BDBA for RBMK-1500 reactors, gained expertise on BDBA analysis and experimental data would constitute an important safety improvement during the remaining time of Ignalina NPP operation and the initial face of decommissioning after final shut-down of the reactors.

The budget for this project is: 650 000 euro
Further Project Results
Further information on the project could be sought from the beneficiary organizations.