Decommissioning of nuclear facilities

The decommissioning of nuclear facilities in Hungary is imposed by § 40 of the Act on Atomic Energy upon PURAM with the additional provision that the responsibility for the maintenance, surveillance and guarding of nuclear facilities from their closure to the dismantling shall be with our Company. The dismantling and the area recultivation work shall also be within the scope of responsibility of PURAM.

Preparation for the decommissioning of Paks Nuclear Power Plant

The first unit of Paks NPP was connected to the grid in 1982, while the fourths unit was commissioned in 1987. The design service life of Paks NPP was 30 years. However, taking into account the 20 years service life extension, the final shut down of Unit 4 of Paks NPP is expected to take place in 2037.

It is shown by the so far followed international practice that for nuclear facilities, which were designed long time ago without use of modern computer aided design tools, the presentation of the design input data in a correct and controllable way mean a very large problem. Moreover, the design input database shall be room oriented, since the decommissioning work will be carried out room by room rather than systems oriented. The structure of the decommissioning database and the database of Paks NPP were established by PURAM in 2004. Upon the request of the Hungarian Atomic Energy Authority, this was reviewed and commented in 2005 by the International Atomic Energy Agency with the involvement of German and Slovakian specialists. The collection of the first batch of data started in 2006 and was finished in 2009.

To ensure that the results of the technological developments and the accumulated experience are used in the preparations, the decommissioning plan is – in accordance with the regulatory requirements – periodically revised. The last revision of the Preliminary Decommissioning Plan of Paks NPP was finished in 2014. It contains the cost estimates and the amount of radioactive wastes for two scenarios, the immediate decommissioning and the 20 years secured preservation of the primary circuit.

Decommissioning of other nuclear facilities

Originally only one scenario, which was matching well to the decommissioning scenario including “70-year closure under surveillance” of Paks NPP, was studied in the Preliminary Decommissioning Plan of the Spent Fuel Interim Storage Facility (SFISF). The reduced period of this safe closure and surveillance is considered in the 2011 revision of the Preliminary Decommissioning Plan of the SFISF facility.

The Training Reactor of the Institute of Nuclear Techniques of the Budapest University of Technology and Economics was commissioned in 1971 to meet the need for the training of nuclear professionals in Hungary. The reactor operates at 100 kW nominal thermal power and has an operation license with a validity up to 2017. It is presumed upon considering the good technical conditions of the reactor that the operation license of the facility will be renewed even until 2027. The necessity of the license renewal is definitely supported by the service life extension of Paks NPP and the requirement for training new nuclear professionals. All in all, the decommissioning of the facility is not expected to occur before 2027. The Preliminary Decommissioning Plan – finished in 2014 – foresees the immediate dismantling of the reactor, while maintaining some functions, e. g. the operation of laboratories in the building.

The Budapest Research Reactor of the Centre for Energy Research of the Hungarian Academy of Sciences was constructed in 1959. A core modification, along with the introduction of a new fuel design, was implemented in 1967. The facility was renewed between 1986 and 1992, a new vessel was installed, and the thermal power was increased to 10 MW. The facility has been operated for research and isotope production purposes. The design service life of the reactor is 30 years, thus the reactor is expected to operate until 2023. The Preliminary Decommissioning Plan is contained in the 6th volume of the Final Safety Report of the facility. The estimated costs of the decommissioning are regularly compared since 2011 with the calculation based on the CERREX software (Cost Estimate for Research Reactors in Excel; IAEA-2011).
Scheduling of the tasks of the decommissioning of Paks NPP and the SFISF:

Scheduling of the tasks

  • Systematic review of Preliminary Decommissioning Plan of Paks NPP and SFISF and establishment and approval of the Final Decommissioning Plan.
  • Shut down of the units of Paks NPP..
  • Transfer of the spent nuclear fuel assemblies into the SFISF.
  • Preparation of the active parts of Paks NPP for safe enclosure.
  • Safe enclosure of Paks NPP and the surveillance and maintenance of the SFISF.
  • Dismantling the inactive parts of Paks NPP.
  • Dismantling the radioactive parts of Paks NPP.
  • Removal of the spent nuclear fuel assemblies from the SFISF.
  • Decommissioning of the SFISF.