22 Mars 2016
March 15, 2016
Nearly half of the radiation monitoring posts installed for issuing evacuation orders around the Sendai nuclear power plant in Kagoshima Prefecture have been found unable to perform the required function.
Twenty-two of the 48 monitoring posts around Kyushu Electric Power Co.’s Sendai plant can only measure airborne radiation levels up to 80 microsieverts per hour, far below the 500-microsievert threshold that triggers immediate evacuation orders, according to a survey by The Asahi Shimbun.
The survey also found that monitoring devices have not been installed at many of the designated locations around Kansai Electric Power Co.’s Takahama nuclear power plant, where two reactors were restarted in January and February.
The two reactors, however, are now out of service again in line with a recently issued court injunction.
These findings mean there are insufficiencies in the way to obtain crucial data for deciding on whether to evacuate local residents from areas around these nuclear plants during severe accidents.
Despite these serious safety lapses, reactors at the two plants were brought online. How seriously do the utilities, central and local governments take the safety of residents?
Nearby local governments that are in a position to monitor nuclear accidents by using these devices should ask the utilities to suspend reactor operations at least until useful radiation measuring instruments have been installed at all the posts.
Following the triple meltdown at the Fukushima No. 1 nuclear power plant, triggered by the Great East Japan Earthquake and tsunami in March 2011, the central government revised its guidelines on responding to nuclear disasters.
The revised guidelines mandate immediate evacuations of residents within 5 kilometers of a nuclear plant where a serious accident has taken place. Residents living between 5 km and 30 km from an accident-stricken plant will be required to stay indoors while the central government decides whether to order evacuations based on radiation levels detected by the monitoring posts.
Immediate evacuations will be ordered if radiation levels reach 500 microsieverts per hour. If radiation levels rise to and stay at 20 microsieverts per hour for an entire day, residents will be ordered to evacuate within a week. In both cases, the central government will issue the orders.
If the network of radiation monitoring posts fails to function properly, evacuation decisions for specific areas could be delayed or misguided.
With financial support from the central government, local governments concerned are required to install these monitoring posts. It is baffling why the local governments that host the two plants consented to the reactor restarts despite the insufficient monitoring installations.
The Nuclear Regulation Authority should not be allowed to shirk responsibility for the matter by claiming that dealing with issues related to the evacuations of residents is not part of its mandate.
The SPEEDI radioactive fallout-forecasting system failed to work properly during the Fukushima nuclear crisis. So the NRA decided to replace the SPEEDI system with networks of monitoring posts to measure radiation levels around nuclear plants for making evacuation decisions.
The NRA should be the one that checks if the posts will be workable in actual accidents.
Even the stricter nuclear safety standards cannot completely eliminate the risk of accidents. That makes it vital to make adequate preparations based on the assumption that nuclear disasters can occur.
The belated acceptance of this internationally common premise doesn’t amount to much if such a lax attitude is taken toward evacuations.
The principle that local governments should take the responsibility to protect local residents from various disasters is reasonable to a certain extent.
However, as far as nuclear disasters are concerned, this principle should not allow the central government to avoid playing a key role and shuffle off its responsibility.
The system needs changes so that the effectiveness of evacuation plans will be sufficiently checked by the central government and especially by the NRA, which has the necessary expertise.
Such reforms will prevent the restarts of reactors under such inadequate evacuation conditions by ensuring central government inspections in addition to safety checks by the local governments concerned.
In some disasters, individuals can make their own decisions concerning their safety. But a nuclear accident is not one of them.
Both the central and local governments should play far greater roles and assume far more important responsibilities in nuclear accidents than in other kinds of disasters.