A safety enhancement program was launched to increase the safety on long term, with its first phase, the so-called demonstration phase, intended to carry out a review of how the waste packages can be recovered, identified, processed and conditioned, and to inspect the condition of the emptied storage vaults. Four vaults were selected for this phase, with three of them with no concrete pouring in the interspace among the packages comprising loose waste (i.e. vaults with no space filling), and with the fourth one with concrete filled space among the waste packages.

When the required licenses were available and after the completion of the preparatory work, Vault A11 was opened on 16 April 2007. The recovery operations were carried out under the cover of a double-wall tent. This vault was loaded with wastes repackaged into plastic bags during the dismantling of the former waste repository at Solymár, and was filled up and sealed in 1980.

The wastes in plastic bags were almost intact, and remained undamaged even during the handling operations therefore, the recovery work was easier than expected. During the sorting of the waste, the waste packages were classified into five categories, which were each conditioned in different manner. The compactible wastes were, directly after sorting, transferred to the pressing machine for compaction. The non-compactible wastes were loaded into a metal drum, and were subject to a repeated sorting to allow further waste processing (cutting and cementation) to start.

The wastes loaded into drums were provisionally transferred into a storage area arranged in the basement of the operational building.

During the implementation of the safety enhancement program, special attention was paid to the tritium containing wastes. Adequate (gas tight and durable) packaging is required for such wastes as specified in a separate procedure.

The work to recover wastes from Vault A13 was commenced on 14 April 2008. In case of this vault, a partial backfilling method by use of concrete mortar was applied during the waste loading operations.. In order to prevent any significant damage of the waste packages, the breaking up of the concrete was carried out slowly and carefully with the use of chipping machines. This operation was of the most labour intensive and time-consuming part of the entire process.

Following the retrieval of the wastes, a status survey of the vaults was undertaken, which resulted in a conclusion that the concrete walls of the vault are in good condition and there is no structural change apart from some minor cracks in the inside surface finish. Thus, no reconstruction of the vault was necessary, and the enhancement of the water sealing capacity was implemented by loading of reconditioned waste packages in the vault and pouring the interspace with space filling concrete. To increase the water sealing capacity, the internal surface of the vaults was coated with geotextile.

The reloading of the reconditioned and repackaged wastes into the vault and, in parallel, the space filling concrete pouring work, were started in early November 2008.

The demonstration program was finished in October 2009.

It was concluded on the first phase of the safety enhancement measures affecting the four vaults, that the recovery of the wastes was relative easily feasible. The conditioning of the recovered wastes was also easy to perform and the condition of the vaults was acceptable. A relative large volume of non-compactible wastes was also recovered and was conditioned by cementation after cutting. Long-lived wastes were contained in around one vault of waste packages. These packages were loaded into interim store for a period until creating the conditions for the disposal.

The removal and processing of wastes from four vaults resulted in the freeing of space of some half of a vault. Since both the desired objectives, i.e. the identification and separation of packages containing long-lived isotopes and the freeing of storage capacities to allow the reception of additional volume of wastes, has been achieved, the safety enhancement measures are considered successfully implemented.

The radiation exposure to those who took part in the demonstration program was very low. The exposure to the workers carrying out the waste recovery work was below the planned limit (which was specified as not exceeding one third of the allowable dose exposure limit).

Since the waste recovery operations were carried out under the cover of a double wall tent, from where no air could get out without filtration, and during the additional operations in the process systems building, discharge could occur in a controlled manner only, the discharge of media (air, water) containing radioactive materials did not increase as compared to the normal operational values. Therefore, the population was not exposed to excess radiation. The radiation protection and environment monitoring systems of the site were continuously functioning throughout the program and did not record any significant deviation from the measuring data recorded under normal operational conditions. Unusual event did not occur during the work. The level of discharges remained below the design level and the licensing limits. The population living in the neighbouring villages was not exposed to excess radiation.