In the second part of this article, we talk about what nuclear decommissioning is. A nuclear reactor is just a huge kettle, but the main difference from a normal kettle, we can not easily trash it, because of radioactive substance contamination. A nuclear decommissioning is a decomposition process to make a reactor to be safely trashed. We would like to talk about a time span and cost of the nuclear decommissioning and what to do about the nuclear waste. We also look close on a on-going decommissioning process example in Greifswald, Germany.
2.1 The time span and cost of nuclear decommissioning
Our current time estimate of nuclear decommissioning is at least thirty years for both immediate dismantling and safe enclosure methods.
The cost of decommissioning is not clear. One reason is that each reactor is highly customized to adapt it to its power plant. The nuclear decommissioning of Greifswald is estimated to cost around 5 billion dollars (Assume 1 dollar = 100 yen in this article).
2.2 A budget of nuclear decommissioning
Usually, a power company owing reactors should allocate money for decommissioning before the plant is shut down. The budget should include the processing cost of high-level nuclear waste. It is usually paid by the fee of electricity. However, Japanese companies don’t need to consider the nuclear waste processing cost since they have a plan a nuclear fuel cycle. The assumption is that establishing this cycle will succeeded, hence they assume there would be no nuclear waste. Therefore, the high-level nuclear waste disposal is not considered. (Footnote of the author: To establish the nuclear fuel cycle, Japan has already spent more than 100 billion dollars and 45 years time. Unfortunately, the current status doesn’t look good yet. The research budget came from the fees of electricity and tax money. [Tokyo Shinbun 2012-1-5])
German power companies are required to save 30 to 36 billion Euro for the nuclear decommissioning budget. Since there is no international standard for the decommissioning budget, some countries have no budget at all. The German government once wanted to establish a governmental fund for the decommissioning. However, the power industry refused to do so, since the power industry didn’t want to give the saved money to the government. Therefore, the plan to establish a fund was dismissed. But, the current estimation tells us that these saving are not enough. Therefore, the industry has changed their mind. Now the industry wants to have the fund backed up by tax money because even if the budget is short, the industry doesn’t need to take the responsibility. They hope the German government would take over the responsibility to cover the cost. In such case, our next generation who never used nuclear energy have to shoulder the cost. We don’t know where this discussion goes yet.
2.3 Waste generated by the decommissioning
The waste produced by a decommissioning process is classified as high/middle/low-level waste, and others. The classification depends on the level of radioactivity as well as on the type of the waste.
- High-level waste: Nuclear fuel.
- Middle/low-level waste: A contaminated waste that was in the nuclear power plant and is handled as a nuclear waste
- Others: A waste that handled as normal waste
The criterion of whether it is nuclear waste or not depends the strength of the radiation from the waste. If the dose equivalence is more than 10 mSv/y, it becomes a nuclear waste. Although there is no guarantee of safety even if the dose equivalence is lower than 10 mSv/y, if it is less than 10 mSv/y, we are allowed to recycle them in the common market. The toxicity of the (fuel) waste depends on the nuclide, the criterion is defined by nuclide.
2.4 Decontamination of nuclear waste
Decontamination of nuclear waste is a process to remove radioactive contaminants from the surface of a non-radioactive substance. We could lower the degree of contamination of the waste by removing the radioactive substances. This reduces the total amount of nuclear waste, therefore this is an important process in the decommissioning.
Please note that decontamination is not the process that makes radioactive substances innocuous. Most of the nuclear waste, e.g., pipes, pumps, etc., are originally not radioactive, but are contaminated by radioactive substances. Therefore we could clean up their surface by high pressure water, high pressure water with steel powder, or by a chemical process (melt off the surface by acid, for instance). Basically, we have not yet had an practical technology to nullify the radioactivity. It means we cannot make the radioactive substance non-radioactive by reasonable cost. Therefore, the only thing we could do is just to collect and store them somewhere and wait decades until the level of radiation becomes low enough.
The radioactivity of these pipes and other objects is lower after the cleanup. In this way, we could reduce the amount of middle/low level nuclear waste. (Decontamination is meaningless for the high level nuclear waste since the high level nuclear waste is usually the nuclear fuel, so clean up the surface doesn’t help to reduce the radioactive dosage since the inside is also radioactive.) Decontamination processes could reduce the total amount of nuclear waste to around 5%.
The remaining 5% waste will be sent to a final processing place (usually we need long term management for the waste), however, this is beyond the scope of this discussion session.
2.5 Decommissioning example: Greifswald nuclear power plant
Greifswald nuclear power plant is executing the largest nuclear power plant decommissioning in the world. Greifswald is located in the north-east of Germany. Five nuclear reactors are in the decommissioning process.
In this discussion, Fukumoto picked up Greifswald nuclear plant as an example of nuclear decommissioning. This plant was granted the decommissioning permission in 1995 and started the process after that. When the plant shut down, there were 10,000 employees (and half of them were working on building new reactors). The size of company organizations in the East Germany tended to be larger than West German organizations at that time. Thus it is not simple to compare the size between the organization and a contemporary organization. For instance, after the German reunification, when the East German companies changed their system to the West German system, some of the organizations drastically downsized. After the shutdown of the Greifswald plant, some people found their job related with a new interim storage construction. Some retired according to early retirement schemes. And some of them work for the nuclear decommissioning company. Currently, 1,500 employees are working for the decommissioning company. Later, several new companies re-use the former site of the plant. Some of them are new green energy companies. Greifswald people are also working for these new companies.
The decommissioning company estimated they had finished 70% to 80% of the process in 2013. However, everything is “learning by doing” as the company’s spokeswoman said. They started the immediate dismantling for the reactor unit one, but by the time they finished the process, it turned out that the cost for the immediate dismantling was too high. This lesson learned made them change the strategy. The new plan is to use the safe enclosure method. They first store the reactor pressure vessel and the steam generator in an interim storage facility for 50 years until the level of radiation becomes low enough and then proceed to the decommissioning process. We don’t know when this process in Greifswald can be completed, but it will most likely take at least until 2045 or longer. Figure 2-1 shows the time line of the life of Greifswald reactors. The author (of this article) could not find out when they decided to use the safe enclosure method. We only know they decided after the reactor unit one is decomposed, but don’t know when it was. We could only say that it will not end before 2045. However, we could not find out how long this process will take.
The total cost of the decommissioning is not clear yet, but the current estimation of the company is 5 billion dollars (1 dollar = 100 yen).
2.5.1 Decontamination process of the nuclear decommissioning
I understand that the decontamination process of decommissioning is done by cutting down the whole nuclear plant to 1m x 1m x 0.7m boxes. Then everything of the plant must be cleaned up. Literally everything, pipes, pumps, containers, walls, … are diced down to put into the boxes for the radiation inspection. If the radiation in the box is detected higher than the defined tolerance level, the box will be returned to the decontamination process again. Actually, the dimension of the box is not clearly shown, this size is rough estimate from the picture we saw in the discussion. (In the picture, a person explained about the box.) Each decontamination worker must wear a special protection suit. They must go through the decontamination process in a small chamber every time so that no radiation will be spread outside of the facility. The process is basically all manual work. All the boxes go to the low-level waste must pass the inspection test. After twenty years of the process, they still have not finished the decommissioning. The estimated current progress is 70% to 80%. Higher radioactive waste will first be kept for fifty years in a interim storage, then the decontamination process of them will start.
The life of a nuclear power plant is not finished when the plant shut down. Even a nuclear power plant closed its operation, there are remaining steps such as decommissioning. Decommissioning process provides numerous employment opportunities for a while. In the case of Greifswald, the skills and know-hows they have gathered became a strength of the city. They are also actively inviting other new businesses to the industry area where the nuclear power plant was located.
A part of the industry area has been used for factories of natural energy. The substations and the grids that were formerly used for the nuclear plant are now being re-used for the offshore wind power plant. These components are shipped to the ocean from the port that was modified from the drain of the nuclear power plant. A new gas power plant, which is under construction, has also a plan to re-use these substations and the grid.
A decommissioning process requires a large number of skilled people for decades. The city of Greifswald is hoping to grow as a pioneer and lead the decommissioning industry in and outside of Germany by using their skills and know-hows.
2.5.2 Summary of part 2
I am surprised that the decommissioning process takes at least more than 30 years. Some parts of the process first need to wait 50 years before starting the actual dismantling. Also we don’t really know how much it costs. Importantly, we don’t know who will pay for it. That depressed me. The fact that the process takes such a long time means that the people who didn’t use the electricity should pay it. And actually it is us and our children. Why should people who didn’t use the energy pay for it? This will be a burden for our descendants. I wonder if this is OK for the future of our country. In this case, parents spend the money of their children, grandchildren, and further descendants. What kind of parents do that?
This — taking money from descendants — has already been started. Some countries started to use nuclear energy earlier than Japan. For example, nuclear energy has been used from the mid-50s in U.K.. Those old reactors had already been retired. However, they started to pay the decommissioning recently. This means a large population of UK, who haven’t used the energy from these reactors, need to pay for the decommissioning. The estimated cost of decommissioning by the NDA (Nuclear Decommissioning Authority) of UK was 49 billion pound in 2010, and then the NDA adjusted the estimate to 100 billion pound in 2013 [The Guardian 2013-06-23].
On the other hand, the people of Greifswald in Germany industrialized the decommissioning process and created employment. I see they are trying to make the future. They are also expecting the big decommissioning time is coming in the world, therefore they have a plan to export their decommissioning technology to other countries. Most of the people don’t want to think about the retired nuclear reactors, therefore people are willing to pay for the decommissioning technology. Some part of me also does not want to think about the decommissioning. I think decommissioning is dangerous, time consuming, and expensive. I found Greifswald people are amazing. They have my respect. I believe I can learn something from them.
So far, we looked into the decommissioning. Now I have some information about it. Then, the next question is “what can I do for that?” Even if I can change nothing, how can I behave with this reality. I would like to think through about it. The next installment will be the last part of this article.
- [Tokyo Shinbun 2012-1-5] 東京新聞: 45年で10兆円投入．核燃サイクル事業めどなく, Tokyo Shinbun, Spent 100 billion dollars and 45 years, No chance of the establishment of nuclear fuel cycle yet. 2012-1-5. http://www.tokyo-np.co.jp/article/feature/nucerror/list/CK2012010502100003.html
- [Greifswald] Wikipedia En, Greifswald Nuclear Power Plant, https://en.wikipedia.org/wiki/Greifswald_Nuclear_Power_Plant
- [The Guardian 2013-06-23] The Guardian, UK’s nuclear clean-up programme to cost billions more than expected, 2013-06-13, http://www.theguardian.com/environment/2013/jun/23/britain-nuclear-atomic-clean-up-decommissioning