The release of radioactive material from a Japan Atomic Energy Agency facility in Tokai, Ibaraki Prefecture, last week suggests scientists still lack a sense of crisis and urgency about radiation dangers despite the 2011 Fukushima disaster.
At least 30 researchers at the Hadron Experimental Facility of the Japan Proton Accelerator Research Complex (J-PARC) sustained internal radiation exposure in Thursday’s accident.
An alarm went off at 11:55 a.m. Thursday in a radiation-controlled part of the Hadron facility when an experiment to generate elementary particles by aiming a proton beam at a target made of gold went haywire. After halting the experiment for the alarm, a researcher in charge decided there was no danger and restarted the equipment just 13 minutes later.
“The safety device went off correctly and there wasn’t a malfunction,” the senior researcher was quoted as saying later.
Soon after, radiation readings in the facility spiked alarmingly to 4 microsieverts per hour — 10 times normal — and officials shut down the equipment. They then ventilated the facility and the internal readings dropped.
But despite the fact that the fan had no radiation filters, it wasn’t until late Friday afternoon that they checked radiation levels outside the facility.
“It was not an appropriate move,” a J-PARC official conceded.
The 1½ days it took the JAEA to report the accident to the Nuclear Regulation Authority, at 10:15 p.m. Friday night, angered both the prefectural and central governments.
“The prefecture is taking the incident seriously. People living nearby are feeling very anxious about the external radiation leak and the internal exposure (of the researchers),” said Shuichi Matsumoto, an official at Ibaraki’s nuclear safety steps division who helped search J-PARC Saturday to probe the incident.
Mitsuhiko Tanaka, a science journalist, said researchers experienced in working with radioactive material generally view leaks of that level as “not a big deal” — a somewhat different perspective from the average citizen since the core meltdowns at the Fukushima No. 1 plant in March 2011.
But in the case of the J-PARC accident, Tanaka said the researchers, who were not used to handling radioactive substances, may have caused them to underestimate the severity of the situation.
It is paramount to find out why they failed to assume that radiation probably leaked from the facility, Tanaka, a member of a Diet panel that probed the Fukushima disaster, said.
“Either the researchers saw the need to take further measures but felt they couldn’t say anything out loud, or they simply thought that nothing more needed to be done,” he speculated.
Meanwhile, Hiroaki Koide, an associate professor at Kyoto University’s Research Reactor Institute, criticized the carelessness of the atomic energy agency.
“It was a result of designing the facility under the assumption that an accident would never happen,” he said.
A senior official at the education ministry, which oversees J-PARC, was also highly critical.
“I can’t believe they failed to report the incident (immediately) when the public is so sensitive to such matters. I’m not sure if they could handle a bigger accident on their own.”
Education minister Hakubun Shimomura is also concerned.
“They lacked a sense of urgency and crisis when the public is harboring strong feelings of distrust toward nuclear power,” he said.