After the Chernobyl accident, a number of technical and organizational changes were developed and implemented in order to improve the operational safety of all RBMKs. These changes were made primarily to:
The aim was to improve the neutronic characeristics of the reactor and to increase the emergency protection system effectiveness and thus diminish the changes of an uncontrolled increase in reactor power.
In the necessity to provide safe operation of the Ignalina NPP, the management of the plant together with the Lithuanian Ministry of Energy and assisted by Western experts prepared a plan to implement the Ignalina NPP Safety Upgrading Program. It was approved by VATESI in 1993. The objective of the safety upgrading program is to maintain the Ignalina operational safety level until it is permanently closed. The program recognizes the need for better fire-protection system, procedures for proper documentation of plant equipment and improved reactor protection system.
Lithuania’s original intention was to contribute about $5 million of its own money to plant improvements. But the program could not be implemented without technical and financial assistance of the Western countries. For this reason, a Grant Agreement was signed on February 10, 1994 in London between the Lithuanian Government, Ignalina NPP and the European Bank for Reconstruction and Development (EBRD) on behalf of the Nuclear Safety Account (NSA). This agreement is the first significant Western financial aid to an RBMK plant from the NSA. The accord provides for a grant of about 33 million ECU pledged by 13 Western donor countries and the European Union. The EBRD money will be used to fund 18 items. The program is due to be completed during 1996. The whole project consists of the following three parts:
The operational safety improvements include non-destructive examination, seals for pressure tubes, routine maintenance equipment, radioactive release and monitoring and a full scope simulator. Near-term technical improvements include seismic upgrading, fire protection equipment and hydrogen monitoring system. These improvements will also include a diversed reactor protection system, neutron flux monitoring system, improved operational data processing, and emergency core cooling system backfits. Services include project management, design and engineering work.
In addition to the safety upgrading program, an in-depth safety assessment of the Ignalina NPP will be undertaken by the end of 1996. A plant-specific Safety Analysis Report (SAR) is produced which will form the basis for decisions on future operation of Ignalina NPP. The SAR aims to:
The safety analysis will consider a safety assessment of both units at the Ignalina NPP. The main reference plant for the project is Unit 1, but a survey is included which defines the differences between Unit 1 and Unit 2 and assesses their safety.
As well as the EBRD-funded Safety Upgrading Program, Ignalina NPP has the ongoing bilateral cooperative projects with Sweden, Germany, USA, UK, France, Belgium, Italy, Switzerland, Canada, Finland and Japan. Sweden is especially active in Lithuania. The two RBMK reactors at Ignalina NPP across the Baltic sea are the closest to Sweden. It makes Ignalina NPP a natural focus-point for Swedish interest. The most important technical safety projects include the fire protection equipment and installation of a pressure relief pipe from the reactor cavity to the accident confinement system. The object of the latter project is to enhance the relief capacity from the reactor cavity by using a remote equipment to install a 600 mm penetration into the cavity. This will make the cavity able to withstand multiple ruptures of 3 up to 9 pressure tubes. Other projects include NDT testing, development and implementation of the plant quality assurance system, physical security and communications system upgrades.