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RADWASTE GENERATION AND RADWASTE MANAGEMENT AT SLOVAK NPPs

The producer of radwaste should assure technically and organisationally to keep the amount and radioactivity of waste as low as reasonably achievable. The complex program of radwaste minimisation is prepared and annually evaluated at each NPP.
Liquid radwaste includes concentrates, sludge, sorbents and oils; the radioactive concentrates are the most important. Total concentrates generation and minimisation trends during recent period (for NPP V1, NPP V2 Bohunice and NPP Mochovce) as well as increasing of their conditioning are presented by the following figure 6.2. Increasing radwaste generation since 1999 was caused by commissioning of NPP Mochovce and higher generation of concentrates during the start of operation.

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Fig. 6.2. GENERATION AND TREATMENT OF RADIOACTIVE CONCENTRATES FROM VVER

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Fig. 6.3. SOLID RAW GENERATION AT BOHUNICE V-1 AND V-2 NPP AND MOCHOVCE NPP

Filters, metal waste, concrete, burnable and compressible waste represent a solid radwaste. This radwaste is preliminary sorted at NPP V1 and V2 Bohunice as well as at NPP Mochovce at the place of its origin according to its activity level and next processing. Exact total data on generated and stored solid waste are not available, because some burnable waste are continually burned and are not in an accountancy and some types of radwaste are recorded by the operator only by pieces, tons or in dependence of storage mode. A trend of solid waste generation (expressed in m3) is presented as an example (Fig. 6.3). A significant increasing of solid waste generation in 1998-2000 was the result of NPP V1 Bohunice reconstruction. The generation of the most important kinds of radwaste in 2001 is presented in the Table 6.4.

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Table 6.4. RAW GENERATION AT NPPs IN 2001

As the original design of NPPs was based on the conditioning and disposal of operational waste only after final shut down, radwaste produced during the operation has been continuously filling in available storage capacity. So nearly 8000 m3 of concentrates were stored at the end of year 2001, representing 75.5% of storage capacity at Bohunice site. Total amount of solid waste stored at VVER NPPs reached 3500 m3 at December 2001. The solid waste storage capacity of NPP V1 Bohunice is spent.
The radioactive waste generated during nuclear installation decommissioning is connected with the range of decontamination, dismantling and demolition works. Management of this waste is described in the following chapter „ NPP A1 Bohunice Decommissioning”.

NPP A1 BOHUNICE DECOMMISSIONING

NPP A1 Bohunice with a heterogeneous reactor using natural uranium, moderated by heavy water and cooled by CO2 had been in operation for 4 years. It was finally shut down in February 1977 after an accident (INES level 4). Recent decommissioning strategy was accepted by Governmental Decision in 1992 and first decommissioning phase occurs in accordance with plan elaborated and amended in 1994-1996. Radwaste management is involved into this plan. In 1999 UJD issued the permit for this decommissioning phase on the basis of „Atomic Act“. Main activities in 2001 were focused on an increasing of radwaste management safety by the waste solidification or storage improvement, especially in the case of inorganic spent fuel coolant. Also one half of vaults was emptied and reconstructed in the original solid waste store. Fragmentation and decontamination of low contaminated scrap has continued.
Historical radwaste from NPP A1 Bohunice represents the special problem for its insufficient sorting and recording during operation. First estimated data for the radwaste inventory exist since 1990, when NPP A1 Bohunice was 13 years after its final shut down. The total volume of liquid radwaste including sludge reached that time 2 112 m3. A part of this waste was evaporated and remaining concentrates were bituminized during 1994-1997. Newly generated concentrates (cca 10 m3 annually) are also bituminized. By the end of December 2001 more than 1400 m3 of liquid radwaste was stored at NPP A1 Bohunice.
The total solid radwaste inventory in 2001 (including filters) represents cca 700 m3 of soft and pre-pressed not sorted waste, 700 m3 of sorted waste, more then 1 000 t of scrap and next 260 m3 of scrap in drums. The total volume of contaminated soils and concrete is more than 7200 m3. The volume of solid radwaste depends on the extent of dismantling works and following treatment, conditioning and disposal. The total volume is also increased by products of bituminization and cementation facilities in drums stored before conditioning at NPP A1 Bohunice site.


 
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