Ryuno Kino | Freelance writer2018/8/27 (Monday) 11:26
Appearance of expanded multi-nuclide removal equipment (provided by TEPCO)
It was found that other radioactive materials were actually left in the water that TEPCO explained that radioactive materials other than tritium were removed from the contaminated water that continues to occur at the Fukushima Daiichi nuclear power plant, so-called tritium water. . After Kyodo News reported that it was left behind on August 19, Hebei Shinpo examined the data for fiscal 2017, and on November 23, the iodine 129 concentration limit (announcement concentration limit) for release stipulated by law Reported that it exceeded 60 times.
TEPCO revealed at the conference on the 23rd that the number of times exceeded 65 times . The author further examined the data and found that the concentration exceeding the notification concentration limit was concentrated in the second half of last year.
Tritium water will be held on August 30th and 31st to discuss future handling policies, but the explanatory materials published by the Agency for Natural Resources and Energy contain iodine-129. It is described as “ND”, that is, not detected (as of August 25).
This document uses what was created by TEPCO in November 2016. Nonetheless, TEPCO repeatedly tried to avoid the answer by repeatedly asking “confirm” when asked about the contents of the document at the press conference. In fact, it was reported on the 23rd that ND was described even though it actually exceeded the standard. “Not only iodine, but the concentration of nuclides may vary depending on the conditions of the filter. Yes, if ND is written, it is ND, and if it is higher than ND, it is shown. " Recognized that there was no problem with the description.
Contaminated water from the Fukushima Daiichi nuclear power plant is stored with a large amount of radioactive cesium and radioactive strontium removed using cesium removal equipment and multi-nuclide removal equipment. Of these, TEPCO has explained that 62 types of radioactive materials can be removed below the notification concentration limit, and that only tritium remains.
For example, in a document TEPCO interviewed with the NRA on November 2, 2016, it states that “62 nuclides have been removed to a concentration below the notification concentration limit”.
The document submitted by TEPCO at the November 11, 2016 meeting of the Sub-Committee on the Treatment of Treated Water of Multi-Nuclide Removal Facilities, etc. The water that has been removed is the state in which most of the radioactive material other than tritium has been removed. Except for ruthenium 106, radioactive substances contained in the stored water are displayed in a graph that cesium 137, strontium 90, iodine 129, cobalt 60, and antimony 125 are below the detection limit.
However, in fact, iodine-129 (I-129), ruthenium-106 (Ru-106), and technetium-99 (Tc-99) out of these 62 nuclides exceeded the notification concentration limit 65 times in FY2017 alone.
Further examination of the data shows that from August 24, 2017 to March 26, 2018, two of the multi-nuclide removal facilities, which are almost always in operation, were expanded 84 times. It was also found that the reported concentration limit was exceeded in 45 of the analyses. This means that half of the operating period exceeded the standard. TEPCO does not explain why it was excessive during this period.
<ALPS analysis results after August 24, 2017. Yellow-filled area exceeds notification concentration limit (created by the author based on TEPCO's published data)>
<ALPS analysis results after August 24, 2017. Yellow-filled area exceeds notification concentration limit (created by the author based on TEPCO's published data)>
TEPCO did not analyze the water stored in the tank. TEPCO showed only the analysis result of the water collected at the outlet of the multi-nuclide removal equipment at a certain time, and the nature of the water finally stored in the tank is unknown. Nevertheless, TEPCO has explained that the water in the tank has removed most of the radioactive material. And for the future, there are no plans for analysis at the moment.
When asked at a press conference about the presence of radioactive materials that could not be removed by the multi-nuclide removal equipment, the target was to reduce the radiation dose at the site boundary to 1 mSv or less per year. It was repeated not to be below the limit. Therefore, the replacement frequency of the adsorbent that reduces the radioactive material was adjusted according to the target.
In addition, all the data on the radioactive materials measured at the Fukushima Daiichi nuclear power plant have been released, indicating that there is no problem.
There is only a big problem with this explanation of TEPCO.
First of all, TEPCO says that there is no problem even if it exceeds the concentration limit because it is suitable for the purpose, but as stated in the above document, TEPCO has explained that it can be below the notified concentration limit with the multi-nuclide removal equipment, It does not explain that the standard is exceeded depending on the operational status. Moreover, in the second half of last year, over 50% of the number of analyzes exceeded, but there was no explanation at the press conference or other public venues. Is this a sincere attitude?
Also, TEPCO's explanation that all the data has been released is not a lie, but it would be too selfish to know what it would be without examining the large amount of data contained in the CSV file.
After all, there are 21 analysis plans for the multi-nuclide removal equipment in use alone, and the analysis period is divided finely, and it is necessary to search while checking the file name one by one. Since files change over time, it is actually difficult to keep track of a single piece of data.
In addition, in this case, even if the analysis results differ from TEPCO's explanation, it was found that TEPCO might not disclose it. It would be almost impossible to confirm the status of the Fukushima Daiichi nuclear power plant from outside. Although there are NRA regulatory offices on Hamadori, there are always 1 to 3 staff members in the nuclear power plant. It's impossible to monitor the site where 5000 workers enter every day.
This week, a public hearing on the handling of tritium water will be held on August 30th and 31st. Until now, the handling of tritium water has been discussed in the government on the assumption that it is almost ND except for tritium (only ruthenium is detected) as described in TEPCO materials. While the premise has collapsed, a public hearing is about to be held.
TEPCO says that it will release the latest data at the hearing, what kind of explanation will it be? Also, how will the organizer's Energy Agency explain to participants that there is actually some radioactive material left? You need to look carefully.