Is there any point in the fuel debris sample collection at Fukushima Daiichi Nuclear Power Station Unit 2?
On September 10, 2024, Tokyo Electric Power Company Holdings (TEPCO) began collecting samples of the debris [1] at Unit 2 of the Fukushima Daiichi Nuclear Power Station. However, it is not the case that we can be satisfied that the decommissioning has reached the main part of the process. There is little point in this sample collection other than to highlight the fact that some debris has been retrieved.
The government and TEPCO say that data on the properties and condition of the nuclear fuel debris obtained through the sampling process will be essential for further decommissioning efforts, including deliberation on the retrieval method. However, the sample that has been collected is just a few grams of the estimated 880 tons of debris, and only a fraction of the debris in a limited area of Unit 2. Even if the sample is analyzed, this data would hardly be representative of the overall properties of the debris. This is insufficient for a study of full-scale debris retrieval methods. If full-scale debris retrieval methods could be studied from just this small sample, it could surely be done without sample collection.
For this sampling plan, the targeted maximum exposure dose for workers was set at 12 mSv. When we check the procedure, there are a large number of processes which require manual intervention and there is ample room for human error. The fact that such a high maximum dose was set for the removal of only a few grams is suggestive of the difficulties that will be faced in debris retrieval in the future.
In fact, the government and TEPCO should think about decommissioning itself, rather than such harsh and pointless debris sampling. According to “The Medium-to-Long-Term Roadmap for the Decommissioning of Unit 1-4 at Tokyo Electric Power Company Holdings’ Fukushima Daiichi Nuclear Power Station,” the decommissioning will be completed 30-40 years after the accident, that is, by 2051. However, in the first place, the decommissioning has been carried out without even an image of how the site will look after decommissioning. Until now, the tasks carried out have been those with either a high degree of urgency or those easy to tackle, such as suppression of the release of large amounts of radioactive materials and the removal of spent fuel from spent fuel pools. It was therefore possible to cope with the situation without having an image of the final state of the decommissioned site. This is no longer the case. There are many issues that cannot be considered without knowing how the site will look after decommissioning, such as how much debris to remove, what to do with the buildings, and what to do with the radioactive waste.
The estimated decommissioning cost of eight trillion yen is the cost up to the point where the debris is removed. When the cost for the disposal of the huge amount of radioactive waste that will be generated is included, it is certain that the cost will be much higher. Since fiscal 2017, TEPCO has set aside an average of 300 billion yen per year as a reserve fund for decommissioning to the Nuclear Damage Compensation and Decommissioning Facilitation Corporation to cover the eight trillion yen cost of decommissioning. By simple calculation, it will take 27 years to accumulate the necessary eight trillion yen. If the decommissioning is to be completed in 2051, the accumulation of funds for waste disposal also need to be considered. But does TEPCO have enough stamina left to do so?
On August 22, the day the debris removal began, TEPCO President Kobayakawa Tomoaki, who had been insisting that ‘fulfillment of the responsibility to Fukushima’ was the top priority of the TEPCO management, was in Kashiwazaki, Niigata Prefecture, giving a presentation on restarting the Kashiwazaki-Kariwa Nuclear Power Station. This episode clearly shows where the management is headed. To what extent is decommissioning of the Fukushima Daiichi Nuclear power Station possible; is it feasible by 2051; and will the funds be ready by then? 13 years have passed since the accident, and if TEPCO were to fulfil their responsibility for the Fukushima disaster, now is the time to conduct a serious consideration of this matter.
[1] Although the government and TEPCO explain that this is debris retrieval, it is simply the collection of fuel samples for investigation, not debris retrieval itself.
Reference (in Japanese): Items required for measures to be taken at Tokyo Electric Power Co., Inc.’s Fukushima Daiichi Nuclear Power Station in line with the Designation as a Specified Nuclear Facility (test retrieval using the Experimental Telescopic Test Device for Unit 2)
