Summary

The objective of the study was to develop a preliminary decommissioning plan and to estimate the related decommissioning costs. The decommissioning plan and the cost figures cover all the necessary actions which will follow the final shutdown, beginning with the preparation of documents for achieving a license for decommissioning and ending with the green field status. This scope includes also the treatment of the existing radioactive waste generated during the operation time and the handling of the spent fuel assemblies. Hence the operation and maintenance work as well as all the activities for project management and administration in the post-operational period were considered and have been included (which is consistent with the standard IAEA content of a decommissioning plan)

Final recommendations between an immediate or a delayed decommissioning strategy are not possible yet, as there is no clear advantage or disadvantage given for one strategy from the technical or radiological point of view.

The differences between the immediate dismantling and the delayed dismantling are not as large as known from the decommissioning projects of light water reactors. This is due to the following:

• the first ten years are strongly influenced by the existing operational waste and the spent fuel assemblies, this period is similar in every strategy
• the safe enclosure of the complete Ignalina building A or of all buildings will be difficult and will need a big operation effort during the enclosure period. The strategies minimum or small safe enclosure (reactor area or main circuit only) are more convenient. But in these strategies and also in the entombment strategy more than 90% of all components will be dismantled in the phase immediately before the safe enclosure period.

A direct advantage of one of the defined strategies can only be found in some detailed aspects:

• for the immediate dismantling the existing systems can be used (e.g. the fuel loading machine), the staff on-site is experienced (after 50 years there is no more experience from the operation) and the staff on site can be employed for a longer period - this is a positive social aspect
• in the delayed dismantling strategy the reactor graphite can remain in place for a period of 50 years. This avoids immediate packaging actions. It is possible that in 50 years a more advanced technique for the management of the graphite will exist
• the financial impact of the real interest rate is not calculable up to now. If the wages will increase to the western Europe standard will correspond with a real interest rate of approximately minus 6%

The current study showed a preliminary decommissioning plan based on different assumptions. The information level and the quality of the input data can be improved by the following way:

• the planning of the dismantling and the waste management of the reactor area and the main circuit components was done with a very rough estimation. This situation can be improved by a neutron activation analysis of this area
• the planning work and in particular the cost estimation should be actualised in a period of 3 to 5 years, taking into account the actual boundary conditions
• the waste management strategy should be checked and adapted when the interim storage facilities are defined and / or constructed
• the relationship between Ignalina Unit 1 and Unit 2 should be investigated in detail. The calculation shows that the total staff will rise up to about 1,800 people. But maximum top value depends on the parallel work in Unit 1 and Unit 2. If this work can stretched the staff can be reduced and the decommissioning equipment can be used twice
• the radiometric plan defines a program for the collection of radiological data. This data can be collected and evaluated during the operational time (and this program should initiated).