New technologies fo LRW treatment. Valentin Avramenko, Far East Branch of Academy of Sciences, Russia

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1 New technologies fo LRW treatment Valentin Avramenko, Far East Branch of Academy of Sciences, Russia

2 LRW MANAGEMENT PRIOR TO 1993 Low-level active LRW NPS operation, repair and decommissioning NTS vessels Technical tankers (accumulation) Dumping into Pacific deep sea NTS vessels (floating workshops) LLRW, ILRW NTS vessel processing into LLRW

3 TRANSPORT REACTOR LRW FEATURES I SOURCE: Operation and repair of nuclear-powered submarines (NPS) and vessels with nuclear power units (NPU) (Navy and icebreaker fleet) TYPES OF RADIOACTIVE WASTE: Liquid and solid ACTIVITY DISTRIBUTION: Low-level active (70%), intermediatelevel active (30%), almost no high-level active LOW-LEVEL ACTIVE WASTE: NPU technological media; reactor flushing waters; decontamination solutions, drain waters of sanitary inspection rooms and special laundries etc. INTERMEDIATE-LEVEL ACTIVE WASTE: This type of waste forms as a result of conducting operations on vessel NPU service, namely, flushing unit circuits; decontamination of stationary and removable equipment; circuit sampling and analysis; changing the filter sorbent; SNF storage in spent fuel container storage units of nuclear technical support (NTS) vessels

4 TRANSPORT REACTOR LRW FEATURES II MAIN FEATURE OF TRANSPORT REACTORS: NPS, surface Navy vessels, ice breakers should have maximum power at minimum reactor size SOLUTION: High uranium enrichment >>> extreme fuel element operation conditions CONSEQUENCES: - Relatively high activity of transport reactors primary circuit (usually higher than for NPP primary circuit) - Significant amounts of strontium-90

5 TRANSPORT REACTOR LRW FEATURES III LRW are formed during active zone recharging followed by SNF management. In average, for 1 reactor the formed waste volume is up to 400 м 3 with activity Ci/l (3, , Bq/l); the filters produce about 0.2 m 3 of active sorbent. Intermediate-level LRW with activity more than 10-2 Ci/l (3, Bq/l) are formed, as a rule, only during NPU emergency situations. In the latter case the waste volume is about m 3, sometimes 1000 m 3 and more, with activity Ки/л (3, Bq/l); during severe emergency situations up to 4000 m 3 with total activity times higher than for regular NPS operation. In average, total volume of LRW formed at vessels with NPU is from 5000 up to m 3 /year (without taking into account sanitary inspection rooms and special laundries). After decommissioning each NPS produces about 400 m 3 of low-level activity LRW (in case of emergency situation intermediate-level waste).

6 MARINE LRW FEATURES Presence of large amounts of 90 Sr as a result of the fuel enrichment high level Traces (in some cases substantial amounts) of seawater Natural seawater contains 9 mg/l of nonactive strontium, i.e. LRW is enriched with strontium non-active isotopes Marine LRW contain substantial anounts of chloride-ions the problems related to equipment corrosion are imminent

7 SORPTION SETUP FOR LIQUID RADIOACTIVE WASTE MANAGEMENT Problematic LRW Selective sorption Disposal or conditioning of decontaminated water (industrial non-active waste) Problems: -complexants -high salinity -oil products Immobilization (conditioning) of expended sorbents (SRW) MAIN POINT: SORPTION SELECTIVITY

8 LRW TREATMENT BY SELECTIVE SORPTION Advantages Possibility of building simple mobile installations Installation low cost Disadvantages Industrial application (Loviisa NPP, Finland, Sellafield, UK) was limited whether by one radionuclide (Cs-137) or by low activity/low-salinity waters No selective sorbents production was available in Russia at that time Nevertheless, the selective sorbents were obtained, and an installation of this type was made and solved many technical problems of the Navy

9 Selective Sorbents and Sorption-Reagent Materials for Separation of Long-Lived Radionuclides µ тв = = µ µ A 0 A + + µ µ B 0 B + RT ln ( c c ) A B = µ 0 A + µ 0 B + RT ln ПР AB r < r min r > r min G = nrt ln * cac ПР * B AB 4πσ мр r 2 r v = 2σ ρrt мр M ln λ AB 10 nm - silicate matrix - Ba 2+ - SO BaSO 4

10 Institute of Chemistry FEBRAS, Vladivostok, Russia NANOSIZE STRUCTURES ON XEROGELS Before sorption from sulfate solutions After sorption from sulfate solutions 16th International Symposium Nanostructures; Physics and Technology, Vladivostok, July 14-18, 2008

11 Institute of Chemistry FEBRAS, Vladivostok, Russia NANOSIZE SORBENT SYNTHESIS ON CARBON FIBERS Metalloxide layer Nanosize sorbents Reduction Nanosize metallic particles Synthesis (ferrocyanide) 16 th International Symposium Nanostructures; Physics and Technology, Vladivostok, July 14-18, 2008

12 Institute of Chemistry FEBRAS, Vladivostok, Russia METAL-CARBON SELECTIVE SORBENTS Sorbent features: - high selectivity - high sorption rate 16 th International Symposium Nanostructures; Physics and Technology, Vladivostok, July 14-18, 2008

13 Institute of Chemistry FEBRAS, Vladivostok, Russia Distribution (Kd) and selectivity coefficients Sr-Ca (Ks) at strontium sorption from seawater Sorbent (Producer) SSW (Institute of Chemistry FEBRAS ) SSW-X (Institute of Chemistry FEBRAS ) DMT (Institute Of Physical Chemistry RAS, Russia) Kd Ks 15,7 74,2 1,6 IE-911 (UOP, Mt. Laurel, NJ, USA ) TiE-96 (UOP, Mt. Laurel, NJ, USA ) Sodium titanate (Allied Signal, Des Plaines, IL, USA) Duolite C-467 (Rohm & Haas USA) ,9 1,2 1,7 1,2 16 th International Symposium Nanostructures; Physics and Technology, Vladivostok, July 14-18, 2008

14 Institute of Chemistry FEBRAS, Vladivostok, Russia SELECTIVTY OF FERROCYANIDE SORBENTS TO 137 Cs IN 4.2 М NaNO 3 SORBENT NZhS (Institute of Physical Chemistry RAS) microcrystals and surface compounds of Ni ferrocyanide on silica gel SNi (Institute of Chemistry FEBRAS) nanoparticles of Ni ferrocyanide stabilized by silica gel Kd Ks * * th International Symposium Nanostructures; Physics and Technology, Vladivostok, July 14-18, 2008

15 Pilot plant of sorbents DalRAO

16 LRW TREATMENT AT NPS IN 2002

17 LRW TREATMENT AT COASTAL FACILITY

18 APPLICATION OF SORPTION/SORPTION- REAGENT TECHNOLOGY IN LRW MANAGEMENT IN THE RUSSIA FAR EAST I OBJECT Coastal facility NTS vessel NTS vessel NTS vessel NPS (6 objects) WORK DONE Drying and processing of LRW tanks in radiochemical laboratory Processing of LRW in emergency tanks Processing of high-salinity LRW down to disposal norms LRW activity reduction in spent fuel assemblies storage for further treatment at Landysh floating plant Drying of circuits and tanks with direct LRW processing down to disposal norms

19 APPLICATION OF SORPTION/SORPTION- REAGENT TECHNOLOGY IN LRW MANAGEMENT IN THE RUSSIA FAR EAST II OBJECT Coastal facilities Coastal facilities Fuel elements cells Emergency NPS WORK DONE Processing of LRW from radiochemical laboratory Complete high-salinity LRW decontamination down to disposal norms Complete LRW decontamination down to disposal norms Reduction of activity of the primary circuit of an emergency reactor (without unloading of active zone) for further processing

20 THANK YOU!