Remove those dosimeters...

April 5, 2018

NRA to remove most dosimeters in Fukushima as radiation drops

http://www.asahi.com/ajw/articles/AJ201804050009.html

By MASANOBU HIGASHIYAMA/ Staff Writer

Japan’s nuclear watchdog will remove 80 percent of its radiation dosimeters in Fukushima Prefecture to slash costs and alleviate unnecessary concerns, as air dose rates have decreased significantly since the nuclear crisis unfolded in 2011.

The Nuclear Regulation Authority (NRA) on March 20 decided to stop using 2,400 of 3,000 radiation meters set up in elementary schools, parks and elsewhere in the prefecture.

While there are 600 extra monitoring posts for long-term radiation measuring, local municipalities and Tokyo Electric Power Co. have also introduced hundreds of dosimeters in the prefecture. The latest removal plan will not cover those long-term radiation meters.

“Although the number of radiation meters will be reduced, our measuring network will never fail to cover any locations when problems occur at the Fukushima No. 1 nuclear power plant,” said an NRA official.

The decision was reached because radiation figures are below the threshold level of 0.23 microsieverts per hour in most areas thanks to the progress of decontamination work, seven years after the disaster started at TEPCO’s Fukushima plant.

Another reason behind the move is that radiation meters will soon reach the end of their operating lives. While the NRA plans to change the arrangement of dosimeters, those installed near the nuclear facility will be maintained.

Under the plan, real-time systems to measure dose rates around facilities for children could be removed in regions sufficiently far from the nuclear plant. Meters in cities, towns and villages that are currently or have once been home to evacuation zones will be maintained.

Most of those areas now report radiation levels as low as before the disaster and readings higher than 0.23 microsieverts per hour are measured at only several points.

The thousands of dosimeters require annual maintenance costs of 360 million yen ($3.39 million).

In addition, the NRA has received complaints from residents, with one of those saying, “The existence of radiation meters could mistakenly make people believe dose rates are high in the area.”

In response to those issues, the NRA decided to reduce the number of dosimeters to around 600 in three years. It will determine which meters to remove after holding talks with residents, starting in April, according to NRA officials.