Japan's nuclear regulators say telecommunication failure was likely the cause for post-quake inaccessibility of data from some radiation monitoring posts around the Shika nuclear power plant in Ishikawa Prefecture.
A total of 116 radiation monitoring posts are set up around the Shika nuclear plant. But data transmission from up to 18 of them was temporarily cut off after earthquakes rocked the prefecture in central Japan on New Year's Day.
At a meeting of the Nuclear Regulation Authority on Wednesday, its secretariat reported the monitoring posts themselves had negligible damage.
Data became gradually available as telecom services were restored, suggesting disconnections and other problems had hampered transmission.
Monitoring posts use multiple means to transmit data, such as cable and mobile phones. But all methods apparently failed after the January 1 quake.
To prevent a recurrence, the authority secretariat plans to enable data transmission through multiple telecom firms, and also diversify monitoring methods, such as by using drones.
Data from monitoring posts are critical in judging whether residents should be evacuated in case of an accident at a nuclear plant.
Municipalities in Hokkaido took steps to ensure continued transmission after data from around the Tomari nuclear plant became inaccessible after the 2018 earthquake.
Authority Chairman Yamanaka Shinsuke told reporters he instructed measures to boost the reliability of telecom systems.
He said the authority will diversify methods of radiation monitoring, such as by using aircraft and drones, for possible disruptions in data transmission.
Yamanaka said the measures will be implemented as soon as possible.