Liquid radwaste treatment systems

FSUE «Alexandrov NITI» is a platform for development of liquid radwaste treatment technologies and equipment. The developed devices differ by their purpose ranging from micro/ultrafilters to integrated radwaste treatment systems.

An integrated approach enables a series or parallel connection of modular units depending on radwaste composition and the desired output. A modular structure allows for variation of modules layout to accomplish any tasks on treatment of middle- and low-level radwaste of complex radionuclide and physicochemical composition determined by the presence of spent decontamination solutions, oil products, suspensions, including those of corrosion products.

The automated operation of a modular membrane-sorption plant (MMSP) and a modular cementing plant (MCP) including an updated concentrate evaporation module (CEM) allows for reduction of staff exposure doses. High purification, concentration, and cementation processes ensure the compliance of produced cement compounds with the current requirements for their permanent disposal.

Modular membrane-sorption setup (MMSS) is intended for concentrating the low-active radwaste of complex physicochemical composition and purifying the filtrate until it meets the existing effluent standards.

The MMSS consists of the following modules:

  • microfiltration module;
  • ultrafiltration module;
  • reverse osmosis module;
  • ion exchange module;
  • reactor-settler;
  • ion exchange resin regeneration module.

MMSS purifies the liquid radwaste until the activity of hazardous radionuclides 90Sг и 137Cs is below the admissible limits.

Microfiltration module is intended for preliminary purification of liquid radwaste from suspended substances.

The module includes:

  • four deep-bed polyamide membrane filters
  • pressure gauge
  • gauge guard

The module enclosure is made of stainless steel. Filter fineness is 20 and 5 µm.
Liquid radwaste purification capacity is 1.5 to 4.0 m3/h

Ultrafiltration module (UFM) is intended to purify the liquid radwaste from suspended substances, emulsified oil products and, partially, from dissolved oil products and surface active substances having sorbed and extracted the radionuclides.

The UFM includes:

  • four tubular or roll ultrafilters
  • flushing unit
  • shut-off and control valves
  • instrumentation and controls
  • pipelines

Liquid radwaste purification capacity is 0.1 to 0,6 m3/h

Продукция — Системы переработки ЖРО: ММО и МИО

Reverse osmosis module (ROM) is intended for concentration and desalination of radioactive water, its purification from radionuclides and toxic substances (heavy metals, surface-active materials, oil products).

Liquid radwaste is supplied to four reverse-osmosis filter elements at operating pressure of 0.6 МPа using a high-pressure pump. The module is equipped with pressure sensors, variable pressure-drop flowmeters with pressure converters, conductivity converters, and adjusting valves.

The ROM includes:

  • high-pressure pump
  • four reverse-osmosis filter elements
  • instrumentation and controls
  • valves and pipelines

Composite high-pressure membranes are used as filter media.
Liquid radwaste purification capacity is 0.25 to 0.5 m3/h

Settling reactor is intended to remove hardness salts from the concentrate downstream of the reverse osmosis module to prevent settling of sediment on reverse-osmosis membrane surface during concentration.

The settling reactor includes:

  • vertical settling reactor
  • shut-off and control valves
  • pipelines

Ion exchange resin regeneration module is intended for removal of radionuclides and ionic impurities from ion-exchange resin.

The module includes:

  • containers for solutions
  • deionized water and acid solution dosing pump
  • valves

The module components may be used for injection of chemical reagents into treated radwaste, liquid radwaste composition correction, and preparation of solutions for washing of ultrafiltration and reverse-osmosis membranes.

MMSS technical characteristics
Ultrafiltration module capacity, m3/hour 0.1 to 0.6
Reverse-osmosis module capacity, m3/hour 0.25 to 0.5
Max working pressure, MPа 7,0
Max salt content of liquid radwaste, g/l 10
Max volumetric activity of liquid radwaste, Cu/l 1 x 10-6
Max volumetric activity of concentrate downstream of UFM and ROM, Cu/l 1 x 10-5
Liquid radwaste temperature, °С 1 to 55
Purification factors
MMSS 103 to 106
Micro- and untrafiltration modules up to 100
Reverse osmosis module 20 to 100
Ion-exchange module 50 to 100
General technical characteristics
Power supply voltage, V 220/380
Currect AC
Frequency, Hz 50
Max powerconsumption, kW 8
Number of operating personnel 3
Number of transport containers, pcs. 1
Dimensions of a transport container, mm 3500х1350х2000
Net weight, kg 1000

Modular cementing plant (MCP) is intended for preparation of liquid radwaste concentrates for disposal by incorporating them into inorganic cementing substances (portland cement, Portland blast-furnace cement etc.).

The MCP consists of:

  • transport unit
  • process unit including:
    • liquid radwaste receiver tank
    • cement hopper
    • liquid radwaste doser
    • cement feeder
    • hydraulic lock
    • control panel

Automated system of MCP process unit is intended to automate production of cement compounds during liquid radawaste solidification, to control and manage solidification processes, and to automatically dose liquid radwaste and initial components for mixing.

The automated system includes:

  • valves control unit
  • secondary convertor of a fluid-level gageв
  • digital device
  • timer
  • three magnetic starters for actuation of a mixer, a feeder, and a vibrator

MCP radiation monitoring system (MCP RMS) is intended to measure gamma radiation doses from plant equipment and at personnel workplaces, beta radioactivity in work space air, as well as to collect information from detection units, and to generate limit exceedance signals.
Signals are displayed at the radiation monitoring panel, personnel workstations, and shift operator’s central board.

The MCP RMS includes:

  • detection units
  • beta radioactivity measuring device
  • distribution device
  • processing device
  • signaling unit

MMSS technical characteristics

Liquid radioactive concentrate treatment capacity, m3/year 100
Average salt content in concentrates, g/l 50
Max salt content in concentrates, g/l 100
Average volume of liquid concentrate for cementation of one cask (drum), l 10
Cement amount required for cementation of one cask, kg 200
Amount of sorbing required for cementation of one cask, kg 20
Working volume of a receiver tank, m3 5
General technical characteristics
Max power consumption, kW 5
Number of operating personnel 3
Number of transport containers, pcs. 2
Dimensions of modules, mm 3500х1350х2000
Net weight, kg 1000