Monitoring Post

• Air radiation dose rate measuring device

   Wide measuring range, from the minute level of nature radiation to the high level detected during some accident, should be assured when monitoring the air radiation dose rate, so that the different types of measuring devices to deal with the each different level are implemented at monitoring posts.

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    Pref. Nagai MP

• Low dose detector (NaI scintillation detector)

   NaI scintillation detector is implemented to measure the dose rate using a phenomenon that a radiation (gamma ray) emits light when it hits a crystal of NaI.
  Under normal condition, the website displays the data measured by the detector.

  
  

  High dose detector (ionization chamber)

   Ionization chamber is used to measure the dose rate using a phenomenon that a radiation ionizes (that is, divides into an ion and an electron) when it hits gas.

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    Low dose detector (left) and high dose detector (right)

• Radioactivity concentration measuring equipment

   In 11 prefectural monitoring stations where are close to the nuclear power plants, the radioactivity concentration is measured by absorbing the air from out of the stations.
   The radioactivity concentration of the air is measured using consecutive floating dust measuring equipment (“dust monitor”). This equipment can measure the concentration of radionuclide that emits alpha and beta ray contained in the atmospheric dust. The value of concentration of radionuclide shown on the website is the one that emits beta ray.
   Concentration of radionuclide can be measured even under normal condition by the influence of radon daughter that is changed from radon that is natural radionuclide contained in the air.
   From the data observed so far, it is confirmed that the radioactivity concentration fluctuates between 0.1 Bq/m³and several tens. (Bq is a unit to express strength of radioactivity.)

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    Dust monitor

• Weather observation equipment

   Air radiation dose rate and radioactivity concentration from natural radiation material fluctuate every day. Therefore, it is important to evaluate if the fluctuation of the observed data comes from the nuclear power plant or from the natural fluctuation by the natural radionuclide.
  Some monitoring station implements weather observation equipment to grasp the weather condition in the observation spot

  
  

  Pluviometer

   It is the equipment to measure the precipitation more than 0.5mm. The white part in the center receives rainfall, and it is surrounded by the shield for wind and birds.

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    Pluviometer

• Precipitation detector

   It is the equipment to detect the precipitation less than 0.5mm that the pluviometer cannot measure. It detects rain when an electrode part gets wet and electricity flows.

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    Precipitation detector

• Wind vane and anemometer

   It measures both wind vane and velocity. Many monitoring centers implement windmill type ones.

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    Wind vane and anemometer