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Hydrogen generation and the risk of hydrogen combustion during a severe accident pose a complex safety issue in relation to accident management. The mitigation of hydrogen hazards in such events may depend directly on knowledge of the hydrogen concentration inside the containment.

The Hydrogen Monitoring System (WS85) measures the local hydrogen concentrations at different locations in the containment during normal operation as well as after an accident.
Thus, it is possible to continuously and simultaneously monitor the local distribution and time history of hydrogen concentrations after an accident.

WS85 consists of hydrogen sensors (inside containment), a signal processing unit (outside containment) and accident-proof cables connecting each hydrogen sensor to the signal processing unit.

The system can be installed in all types of reactors: the areas to be monitored and the locations of the sensors are assessed individually for each nuclear power plant layout. Because of its clas- sification as a post-accident monitoring system and the required reliability, all components which are located inside compartments subject to accident conditions (hydrogen sensors and instrument cables) successfully passed an extensive type test program including all specified loads during normal operation and loss-of-coolant (LOCA) accidents.

If required, the sensor system can be delivered with an uninterruptible power supply and a calibration trolley.

Your Benefits

  • In-situ measurement provides live information on containment gas composition
  • Easy and effective to retrofit, no containment penetrations for piping are needed
  • Reliable and accurate measurement ensured by functional testing of the sensors during online periodic inspections
  • Easy and fast periodic testing using mobile unit anticipated in design
  • Small demand for battery capacity or emergency diesel power because of low electrical power consumption


  • Germany: 11 – PWRs, BWRs and laboratories
  • Spain: 7 PWRs
  • Switzerland: 3 PWRs
  • Argentina: 1 PHWR
  • Finland: 3 – PWRs and VVERs
  • India: 1 PWR
  • Sweden: 3 PWRs
  • Czech Republic: 4 VVERs
  • Slovakia: 2 VVERs
  • Ukraine: 6 VVERs
  • Bulgaria: 4 VVERs
  • China: 4 VVERs
  • Japan: 8 BWRs

PWR: pressurized water reactor
BWR: boiling water reactor
VVER: water-water power reactor
PHWR: pressurized heavy water reactor

Interested in In-Situ Containment Atmosphere Hydrogen Monitoring System – WS85?

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