Radiation dose measurement status at water purification plants

We publish measurement result of space radiation dose in water purification plants of Water Works Bureau as follows.
Since September 2011, we have been measuring spatial radiation doses at the Yokohama Water Supply Memorial Hall and water purification plants that customers visit for tours, etc., but since the start of the measurement, all measured values have fallen below the standard of response in Yokohama City. Since 10 years have passed since the earthquake, measurement of spatial radiation dose at water purification plants was completed with the measurement in April 2021.

Measure the position of 1cm and 50cm from the ground.

[Standards for Response in Yokohama City]
・1 cm from the ground surface ：0.59μSv/h
・50cm from the ground surface: 0.23μSv/h

Yokohama Waterworks Memorial Hall, Nishiya Water Purification Plant, Kawai Purification Plant, Kosuzume Purifiction Plant, Aoyama Water Source Office

※From April 2015 to April 2021, measurements were taken at 23 locations in 5 facilities.
※In October 2014, measurements were taken at 24 locations in 5 facilities.
※Measurements from September 2013 to April 2014 are 25 locations at 5 facilities.
※Measurements from May 2012 to August 2013 were 23 locations at 5 facilities.
※Measurements from March to April 2012 were 83 locations at 5 facilities.
※Measurements were taken from November 2011 to February 2012 at 94 locations in 5 facilities
※Measurements in September 2011 were 139 locations at 5 facilities and 7 reservoirs.

Radiation Monitor “Radi” (PA-1000) (CsI (TI) scintillation detector) (produced by HORIBA, Ltd.)
※In September 2011, the NaI (TI) scintillation detector TCS-172B (manufactured by Hitachi Aloka Medical, Ltd.)