9 Juin 2017
June 8, 2017
EDITORIAL: Radiation exposure reveals lax safety at nuclear agency
An exhaustive investigation should be made into an accident on June 6 that exposed workers to radiation at a nuclear energy research center in Oarai, Ibaraki Prefecture.
The probe should answer questions as to why the accident occurred and whether it was possible to prevent the internal radiation exposure.
Workers were exposed to radiation at the Japan Atomic Energy Agency’s Oarai Research and Development Center after radioactive materials escaped from a nuclear fuel container.
One worker in his 50s was found to have 22,000 becquerels of plutonium in his lungs. A rough calculation of the 22,000-becquerel figure translates to internal radiation exposure of 1.2 sieverts over one year and 12 sieverts over 50 years.
The level of the worker’s internal radiation exposure is certain to surpass the safety standards for workers at nuclear plants.
There have been no past examples of such a high level of internal radiation exposure in Japan.
So far, none of the workers has complained of health problems, according to the operator, but it is necessary to monitor their health conditions over the long term.
The accident occurred when the workers were inspecting the storage conditions of the nuclear fuel, such as uranium and plutonium.
When one of the workers opened the lid of the container, the plastic wrapping of the fuel was ripped, and radioactive materials were spewed into the air.
There are a raft of questions that need to be answered. Why was the wrapping ripped, for instance? Were there any problems with the work procedures?
What is disturbing is that the agency said it never assumed the plastic might rip.
Plutonium, when absorbed into a human body, stays inside for a long time, continuing to emit radiation and possibly causing cancer and other health problems.
If it leaks outside the facility, local residents in surrounding areas also face the risk of developing health problems.
In dealing with plutonium, maximum care is required for any type of work. The accident inevitably raises the suspicion that the agency failed to take sufficient care in dealing with potential safety risks.
According to the agency, the research center has a facility for handling radioactive materials in a tightly sealed environment. But the facility was not used for the work. The workers, although they wore protective clothing, wore face masks that only covered their mouths and noses instead of full-face masks to cover their entire faces.
Usually, workers at places where they can be exposed to radiation wear full-face masks.
The agency said it did not expect that the workers could be exposed to radiation, but they wore the half-face masks just in case.
It is doubtful whether the safety management system for the workplace was adequate. Thorough efforts should be made to delve into this issue.
In 2015, the Nuclear Regulation Authority said the Japan Atomic Energy Agency was not sufficiently equipped to safely operate the Monju prototype fast-breeder reactor.
It was also revealed that the agency’s management of radioactive materials at its spent-fuel reprocessing plant in the village of Tokai, Ibaraki Prefecture, was grossly lax.
The agency has already announced a plan to scrap the research center that has been hit by the latest accident. It is now working to confirm the types and conditions of radioactive materials at the center for its closure.
Isn’t it that the agency’s attention to safety issues at the center has declined as its research and development functions have stopped?
The agency should make a fresh and rigorous review of its awareness of the safety risks involved in dealing with radioactive materials.