1. Operational RW and SNF of Russian VVER and RBMK reactors
The technologies of managing RW produced by the operation of NPPs with different reactor types are practically the same.
The differences are explained only by the amount of generated gaseous, liquid and solid waste. RBMK-1000 reactors produce much larger RW (especially LRW) than in the VVER-440 reactors.The LRW depends largely on which water (sea or fresh) is used for the turbine condensers cooling.
Generation of liquid radioactive waste (LRW)
During the NPP operation, LRW arises from the purification of the first circuit coolant, decontamination operations and repairs, washing of protective clothes, etc.
LRW from processing filter materials and first circuit decontamination amounts to 10 % of the total volume of operational LRW. The activity of this type of waste is from 1×10-5 Ci/l to 1 Ci/l and, in accordance with OSPORB-99 norms, belongs to middle-level waste.
LRW arising from the decontamination and maintenance (repairs), trap water, etc.,
which accounts for 90 % of the total waste volume, has an activity of up to 10-5 Ci/l and belong to low-level waste.
The four power units of Leningrad NPP produce about 16,000 m3 of LRW every year.
All LRW produced during operation is transferred to special storages to undergo volume reduction and conditioning. The annual accumulation of conditioned (concentrated) LRW (per one RBMK-1000 power unit) is 202 m3.
At present Leningrad NPP stores 18,500 m3 of conditioned LRW.
The volume of LRW arising after VVER-440 reactor flushing is ~150 m3, which is lower by one order than volumes produced during RBMK-1000 reactor operation (~1200 m3).
This is explained by the difference of technologies applied, reagents used for flushing to remove deposited corrosion products, also by a much smaller volume of the VVER-440 reactor circuit. In 2008 a low-waste facility for processing homogeneous LRW will be put into operation, its capacity of 1000 m3/year will enable to process not only newly-produced, but also accumulated LRW.
The total amount of LRW, which is yearly produced by the four power unit NPP with VVER-440 reactors is about 1600 m3. Their average specific activity is - 1×10-4 Ci/l.
This topic focuses on the existing experience of long-term isolation of radioactive wastes from the environment in Russia