Equipment of the V3H14C family are designed for 3H and 14C sampling from the air. Several versions are produced, ranging from a compact model for the sampling of tritium in the form of water, to a version enabling differential sampling of both the oxidised and unoxidised form of tritium, and the organic and inorganic form of 14C.

  

PURPOSE

Equipment of the“V3H14C” family is designed for 3H and 14C sampling from the air. The samples are captured into sorbents, the standard sorbent for 3H is silica gel (optionally another one), and the standard sorbent for 14C is sodium hydroxide.

The equipment is produced in several versions. The version of the sampler is selected depending on the requirement of which radionuclides and forms are to be sampled.

Fully equipped model V3H14C includes two separate sampling lines for the sampling of different 3H and 14C forms. The first line is equipped with catalytic combustion and is designed for capturing 3H and 14C in all forms including H2, CO and CxHx. The second line is designed for 3H and 14C sampling, exclusively in the basic form H2O and CO2. By comparing the difference in both captures, it is possible to determine the total amount of the substances under investigation in both forms - both the oxidised and unoxidised form of tritium, and organic and inorganic form of 14C.

Desorption unit DJ-500 may also be part of the system, serving for releasing water captured in the silica gel sorbent.

The extracted samples are designed for subsequent laboratory analysis. Values of activity of samples, resulting from the analysis, serve for quantitative assessment of radioactive emissions of 3H and 14C and for comparing with the determined limits.

  

DESCRIPTION

The equipment is designed for installation on a wall or other suitable structure. It is controlled using buttons on the control panel. On the graphic display, it is possible to read the total amount of sieved air, current flow rate through the sampling lines, time of operation and all monitored values, such as temperature, pressure, and humidity in the line, and the temperature of the catalyst (for models with a catalyst).

The air flow may be constant, or it may be adjusted proportionally to the value present at the equipment control input (typically to the flow through the ventilation system, from which the sample is being extracted). It is adjustable in each sampling line separately. The set flow rate influences the duration of the sampling campaign. The flow through the individual lines may be limited by the parameters of the sorbent, and by the catalyst filling. The pump is microprocessor-controlled, which enables high accuracy of flow rate adjustment (contrary to flow control with the help of a throttle valve).

It is possible to set alarm levels for the measured values and the equipment signals exceeded limits.

V3H14C includes a serial communication interface that enables checking the equipment status, reading of measured values, and remote controlling of the equipment using a PC from the host system. Software for remote checking and control is delivered as an optional accessory.

The equipment may be optionally equipped with an external cyclic archive, enabling local storage of measured values and status messages. The saved values may be transferred to the host system using the RS-485 interface.

Basic sorption media are silica gel (amorphous silica) for capturing 3H and sodium hydroxide (NaOH) for capturing 14C. These media enable reliable operation even in case of longer exposition at high sample humidity.

When using silica gel with an indicator, capturing of humidity is indicated by progressive change of its colour.

The sorbents are filled into glass sampling bottles and the bottles are screwed into the holder in the laboratory; for safety reasons only assembled bottle arrays are handled at the sampler’s location. During normal operation, the sorbent should be normally exchanged on a weekly basis.

Fully equipped model V3H14C includes two lines for the extraction of samples. In the common intake section, there is an aerosol filter, a flow meter, and meters of pressure, temperature and relative humidity. The first line includes a pump, a catalyst upstream the bottles with sorbents, sampling bottles with silica gel, a mass flow meter and sensors of pressure, temperature and relative humidity, an overflow trap bottle and the sampling bottles with NaOH. The second line is analogous, but does not include the catalyst. Within one extraction line, 3H extraction precedes the 14C extraction, and the sorption medium of 14C is thus protected against humidity. Downstream the 3H extraction, and upstream the 14C extraction the humidity is measured, which enables the check of the efficiency of the extraction of water by silica gel. In the output section, there is a common output aerosol filter. It is possible to install a condensation vessel outside the equipment for draining condensate from the line behind the equipment.

The first line is equipped with heated platinum catalyst, the second one is not. Thanks to this arrangement, contrary to equipment with both lines (without and with a catalyst) in serial arrangement, sufficient amount of sample downstream/behind the catalyst is assured, and the activity uncertainty is thus lower. The catalyst temperature is adjustable in a broad range with high accuracy and is permanently measured and checked.

  

MAIN ADVANTAGES

  • Easy, fast and secure replacement of mechanically resistant sampling recipient bottles
  • When using silica gel longer sampling time or sampling of higher amount of tritium is possible compared to liquid sorption media
  • Parallel arrangement of sampling lines (one line with a catalyst and one without it) provides a sufficient amount of a sample from both lines for further analysis; thanks to that the results are more accurate compared to serial arrangement
  • Wide range and high accuracy of the flow rate adjustment
  • Measurement of the humidity downstream the tritium capture (only certain models)
  • Remote checking and control from the host system
  • Proportional sampling relative to flow in the ventilation stack enables calculation of the amount of released 3H and 14C (optional)

  

MODELS

  • Differential sampler of both the oxidised and unoxidised form of tritium 3H, and the organic and inorganic form of 14C
  • 2 sampling lines, 1 with catalyst Sampler of both the oxidised and unoxidised form of tritium 3H, and the organic and inorganic form of 14C
  • 1 sampling line with catalyst Differential sampler of both the oxidised and unoxidised form of tritium 3H
  • 2 sampling lines, 1 with catalyst Sampler of both the oxidised and unoxidised form of tritium 3H
  • 1 sampling line with catalyst Sampler of unoxidised form of tritium 3H
  • 1 sampling line without catalyst, compact model

  

  

SPECIFICATION

Flow rate through one sampling channel, adjustable

50 ÷ 500 ml/min

Uncertainty of measured flow rate

max. ±5 %
for flow ≥ 100 ml/l

Volume of sampling bottles in one bottle array

3 x 250 ml

Sorbents

- silica gel
- sodium hydroxide

fraction 3 ÷ 6 mm (grain size), 3 x 170 g (dry) in one bottle array
solution, concentration 3 mol/l, max. 3 x 200 ml in one bottle array

Collection efficiency

     

95 % ±5 % collection H2O in silica gel
99 % ±1 % collection CO2 in NaOH

Sorption capacity in one sampling bottle array
(maximum, declared for specified efficiency)

30 g for Silica gel
18.5 g for NaOH

Minimum detectable concentration *

approx. 0,01 Bq/m3

Volume of overflow trap bottle (for models with NaOH)

500 ml

Catalyst temperature, adjustable

250 ÷ 550 °C, přednastavená na 460 °C

Power supply

100 ÷ 240 V AC

Power consumption  

- models with catalyst
- models without catalyst

max. 140 W
max. 25 W

Operation temperature range

+5 ÷ 40 °C

Dimmension (W x H x D) 

- V3H14C, V3H14Cs, V3H, V3Hs
- V3Ha

cca 620 x 805 x 265 mm
cca 464 x 558 x 261 mm

Weight

- V3H14C, V3H14Cs, V3H, V3Hs
- V3Ha

45 kg
13 kg

Display

graphic, 120 x 32 dots

Communication interface

RS-485 / RS-232

Sampled air Temperature

+5 ÷ + 40 °C (41 + 104°F)

Sampled air Pressure

96 ÷ 106 kPa (720 + 795 mmHg) 

Sampled air Relative Humidity

max. 80% non cond.

 * Equipment of the "V3H14C" series only collects samples; the samples are analysed in the laboratory. The above mentioned values are based on ordinary laboratory LSC analysers (liquid scintillation counters), they correspond to performed tests, and are well proven in practice in nuclear power plants.

OPTIONAL ACCESSORIES

  • Software application for remote control
  • Local Data Logger for V3H14C
  • Transport box for sampling bottles in the holders

  

CONSUMABLES AND SPARE PARTS

  • Holder with sampling bottles for silica gel
  • Holder with sampling bottles for NaOH
  • Catalyst
  • Aerating stone

  

RELATED PRODUCTS

 

 

 

GET EXPERT HELP

 

 Specifications, standards and device design may be subject to change with regard to device development or specific customer design, without prior notice of change.
Please contact our representative to confirm the information provided on this website.

You could be interested in

Noble Gas Detectors

Noble Gas Detectors

A detector for the continuous measurement of the noble gases beta and/or gamma volumetric activity in ventilation stacks effluents and in technological systems

Detail

Digital High-Volume Air Sampler

Digital High-Volume Air Sampler

An air-sampling device designed to evaluate the air pollutants captured on filters (radioactive aerosols, dust, etc.)

Detail

Very High-Volume Air Sampler

Very High-Volume Air Sampler

A high-volume air sampler for the measurement of environmental contamination with radioactive substances

Detail

Desorption Unit

Desorption Unit

A device intended for water desorption from sorbents of silica gel type

Detail

  • 60+
  • products for
    nuclear power plants
  • 4
  • different type
    of gamma irradiators
  • 3500+
  • annual distribution
    of contamination monitors
VF, a.s.
Headquarters
+420 516 428 611
The Czech Republic
Svitavska 588, 679 21 Cerna Hora


Certifications and authorisations