Efforts to settle the nuclear accident in Fukushima continue to hit snags Nuke Info Tokyo No. 156
Japanese Prime Minister Shinzo Abe assured the International Olympic Committee (IOC) on September 8, 2013 that radiation leaks at the Fukushima Daiichi Nuclear Power Station were under control and did not pose any health risks.
Speaking to the IOC meeting prior to the vote to decide on the 2020 Olympics host city, Abe referred to this major issue that had raised doubts about Tokyo’s chances of holding the event.
“Let me assure you the situation is under control. It has never done and will never do any damage to Tokyo,” he stressed.
Meanwhile, the crippled Fukushima Daiichi Nuclear Power Station is producing massive amounts of radioactive water that are flowing into the ocean every day. The plant operator, Tokyo Electric Power Company (TEPCO), has also admitted that the radiation leaks are not fully contained within the nuclear power plant harbor.
The nuclear power plant workers, local fishermen and many other citizens were shocked to hear the prime ministers’ totally groundless comment, voicing criticisms and anger. In addition to the buildup of contaminated water, troubles have emerged one after another on the plant premises, such as sudden rises in radiation level in some places and many incidents of workers receiving exposure to high-level radiation.
Did removal of rubble and wreckage cause worker body contamination?
It has been confirmed that the heads and hands of ten TEPCO employees were exposed to radioactive substances when they were leaving the Fukushima Daiichi Nuclear Power Station on August 12. They were sprayed with water from the mist generator installed at the plant for prevention of heat stroke. At first, the mist generator or the water from the device was thought to be the source of the contamination.
On August 19, radiation levels of up to 13.3 Bq/cm2 (the government’s exposure criterion is 40 Bq/cm2) were detected from the heads of two workers who had finished work and boarded a bus outside the main earthquake-proof building. An examination of dust collected from the air in front of the building indicated that the radioactive cesium level had increased there.
TEPCO announced on August 29 that the radiation exposure of the 12 workers waiting for a bus in front of the earthquake-proof building on August 12 and 19 is believed to have been caused by scattered radioactive substances generated by two operations being carried out on top of the Unit 3 reactor building, some 400 meters southeast of the earthquake-proof building. One of the operations was the removal of a bridge-type crane for carrying nuclear fuel, which was conducted on August 12, and the other was the rubble and wreckage removal operation carried out at the same location on August 19. On both days, winds were blowing from the reactor building toward the earthquake-proof building. It is said that the removal operations were being carried out while the alarm was sounding. In addition, while the workers were waiting for the bus, the alarm on the radiation counter installed in front of the earthquake-proof building was also said to have been sounding, indicating that the radiation levels in those places were high.
Internal exposure levels of plant’s workers engaged in emergency operations
Pressed by international organizations, the health ministry has re-evaluated worker internal exposure levels
The Ministry of Health, Labor and Welfare (MHLW) announced on July 5 that it had revised the internal exposure records for 479 workers engaged in emergency operations at the plant. According to the ministry, some of the data recorded in TEPCO’s reports were not correct. The reports were compiled based on data from the plant makers and other subcontractors.
The ministry said it had checked closely the FY2011 and FY2012 reports on the internal exposure levels of the workers which were submitted to the ministry by TEPCO at the end of April, and discovered that there were some discrepancies between the exposure levels assessed by the subcontractors and those provisionally assessed by the utility company. The ministry, therefore, launched a re-assessment of the records in May.
Of the 19,592 workers engaged in the emergency operations at the plant between March 11 and December 2011, 452 were exposed to higher amounts of radiation than recorded levels, with the largest gap reaching 48.9 millisieverts (mSv), the ministry said.
After the correction was made by the end of March 2013, the number of workers whose total dosage topped 50 mSv increased by 24 (of these, six were exposed to more than 100 mSv).
Although the official limit of the plant worker’s five-year exposure to radiation is set at 100 mSv, at least two of the above-mentioned workers were confirmed to have continued to work after that period without knowing that their total dosage had exceeded the limit.
Immediately after the nuclear accident, there was a serious shortage of whole body counters for measuring internal exposure to radiation, and many workers were unable to check their dosage for several months. In such cases, the calculation of the total internal exposure is generally done by taking into account the current dose and the length of time since the worker began absorbing radiation.
The ministry’s investigation has revealed many questionable cases. For example, a case in which the exact time when the worker began absorbing radiation was not known, but was recorded as the middle of the March-December period. The general rule is to regard the starting time as the time when the worker began working in a radioactive environment.
In other cases, input errors of the data for 29 workers, mixed-up data, and other types of mistakes were discovered. As a result, a total of 479 errors and mistakes were found in the records for a total of 19,346 workers, the ministry said.
In July 2011, the Nuclear and Industrial Safety Agency ordered TEPCO to clarify the dosage calculation rules but the plant operator failed to fully comply with the order. Later, some scholars and intellectuals warned that the dosage calculation would be made inappropriately if TEPCO did nothing about it, but the utility completely failed to look into the matter.
Pressed by the international organizations probing into the harmful effects of radiation exposure, TEPCO submitted data on age-specific doses of the workers with distribution charts of their internal-exposure and thyroid equivalent doses to the World Health Organization in March 2012. Earlier this year, some of the international organizations posed questions about data in the report, which prompted MHLW to launch its investigation into the matter.
Most of the internal exposure of the workers was thyroid exposure to radiation suffered immediately after the nuclear accident. Concerning the thyroid equivalent doses, TEPCO reported the data for 522 workers calculated with the use of their actual measurements of exposure to iodine 131. Of these workers, the doses of 178 workers exceeded 100 mSv, the report said.
This time, TEPCO expanded the scale of its survey, and when the worker’s exposure to iodine 131 was not clear, it calculated their doses based on the worker’s exposure to cesium. The result of this survey showed that as many as 1,973 workers suffered high-level exposure of more than 100 mSv.
Since March 11, 2011, CNIC has been holding negotiations with the government’s ministries and agencies concerned through various channels, in cooperation with many other organizations, such as the Japan Occupational Safety and Health Resource Center and Radiation Exposure Opposition Campaign.
As for the issue of nuclear power plant workers’ exposure to radiation, we negotiated with the government officials for the tenth time on June 20.
Since the outset of the negotiations, we have maintained that TEPCO conducted appropriate dosage assessments only for its own heavily-exposed employees, but did not do so for heavily-exposed workers hired by its subcontractors and cooperating firms.
We have repeatedly demanded during the past two years that the ministry clarify the methods of dose calculations adopted by TEPCO’s subcontractors and cooperating firms. The ministry finally launched its action to investigate the matter, not in response to our demand, but in surrender to pressure from the international organizations. Their stance concerning this problem is, therefore, questionable.
The recent re-investigation of internal exposure has covered the workers of plant makers and companies specializing in nuclear plant work, as well as temporary officials employed by TEPCO. However, there were other workers engaged in emergency operations who were exposed to high-level radiation, such as the security guards who continued to guard the front gate immediately after the outbreak of the nuclear accident and at the time of the explosion in the reactor buildings. They probably had no time to take rests or eat meals in other places for several days. The ministry should conduct sufficient hearings on such people and re-assess their doses correctly.
TEPCO’s policy of recording only doses above 2 mSv in the radiation exposure management notebook and omitting smaller doses is not justifiable.
An official of the Industrial Health Division of MHLW’s Labor Standards Bureau in charge of health protection measures for workers exposed to ionizing radiation said the ministry is conducting assessments of worker internal exposure levels once every three months, screening doses of more than 1 mSv to find out if the total exposure level exceeds 20,000 cpm. The exact number of counts is actually kept, but counts of less than 2 mSv are recorded as “zero” in the official radiation-exposure management notebook, he said. “In the International Commission on Radiation Protection’s general rules concerning protection of workers from radiation, entitled ICRP pub.75, there is a rule that excludes counts of less than the designated level, and we are following the rule.”
Published in 1997, the ICRP pub.75 did not foresee disastrous accidents at nuclear power plants that could not be settled for several years, such as the one that has occurred in Fukushima.
It is extremely important to have a correct record of internal exposure levels of the workers engaged in various operations at the plant where radiation leaks continue. The internal exposure problem is becoming more and more serious for the workers engaged in the tasks of decontamination and disposal of radioactive wastes.
Management of radiation exposure data for decontamination workers
There is also the deplorable situation where the employers of decontamination workers are not sending worker radiation exposure data to the Radiation Effects Association (REA) Radiation Dose Registration Center (RADREC), a public interest incorporated foundation for registration and management of exposure doses. This means that the decontamination workers working under new employers are not informed of their cumulative doses. Some exposure-dose records can be lost if an employer goes bankrupt. Without such data, decontamination workers will have difficulties in applying for workers’ compensation.
The seventh negotiation with the government was held on June 24 jointly with eight other organizations and groups, such as the Radiation Exposure Opposition Campaign. The discussion was based on the statement calling for “the protection of health and lives of workers and residents, and compensation for health damages caused by radiation exposure.”
In this negotiation, MHLW expressed its position that it is desirable for decontamination business operators to promptly register their worker radiation exposure data with the RADREC, a private database, as soon as their doses are confirmed, though it is not mandatory. The ministry said this in response to the question raised prior to the negotiation about the unified management of exposure data for emergency operation workers at the Fukushima nuclear power plant.
In this negotiation, the Environment Ministry official said, “After five years, the dosage data can be handed over to the designated organization. In this case, the employers will be released from the duty to keep the data for the remaining 25 years.” “However, in the case of the Decontamination Ionizing Radiation Ordinance, there are no such rules and the employers cannot hand over their workers’ dosage data to other organizations. If MHLW, which has expertise in the Industrial Safety and Health Act, makes such rules, we will follow them,” said the ministry official.
We feel that MHLW should take the initiative in safety management of decontamination workers.
(Mikiko WATANABE, CNIC)