Japan Atomic Energy Agency


	
	
	


	

The measuring data of air dose rate monitor, canal discharge monitor, Stack gas monitor, or weather observation may miss because of maintenance of measuring equipment or data transferring computer.
In such cases, the data is displayed as “under maintenance”.
Air dose rate may fluctuate largely due to the influence of rainfall or snowfall.
In particular, air dose rate fluctuate periodically due to daily fluctuation of radon and its progeny nuclides concentration in the air which are produced from natural uranium and thorium in the soil.
The measuring data of canal discharge monitor may change due to rainfall or snowfall.
In winter, air dose rate may increase momentarily due to the influence of thunderbolt.
From 9 a.m. on February 10th to 4 p.m. on February 18th in 2025, there are going to be periods when all data is "adjusting" due to the update of computers at Japan Atomic Energy Agency.
Although, during this period, all monitors operate properly and measure radiation continuously.
The Monju MS transmission is scheduled to end on October 10, 2025.
As part of its voluntary safety activities, Monju MS has been measuring environmental radiation on the Monju site.
In May 2025, following Monju's designation under the Cooling Announcement and considering that the Monju MS equipment is approximately 30 years old, a decision was made to end its transmission 
in order to reduce the risk of failure associated with equipment degradation.
There are four Monitoring Posts (MPs), designated as Monju MP1 through MP4, located at the boundary of Monju's peripheral monitoring area. Therefore, radiation monitoring is being conducted as
necessary and sufficient at these locations.
From 11:00 on October 14,2025 to 15:00 on November 6, 2025, the Matsugasaki MS is going to be "Under Adjustment" for facility renewal. 
A portable monitoring post had been used for substitute and continuous surveillance during this period.
Data collected during this time is available here.