“We have a responsibility to future generations”

Nuclear energy issues run like a red thread through Michael Sailer’s curriculum vitae. Early on in his career, he campaigned for the phasing out of nuclear power. Today, he is the Chairman of the Nuclear Waste Management Commission (ESK) and a member of the Commission on the Storage of Highly Radioactive Materials. Michael Sailer is a critic of nuclear energy and a high-profile expert on the nuclear industry. For the last 35 years, he has put this expertise to good use on behalf of the Oeko-Institut. He has been a member of its Executive Board since 1999. He talks to eco@work about his involvement in the search for a final storage site, the problematical issue of interim storage, and the criteria that must be met by a German repository.

Mr Sailer, why is being involved in the search for a final storage site so important to you?

We are responsible for the nuclear waste produced in Germany, so we need final storage facilities in Germany. To me, that’s beyond question. I think it would be immoral simply to leave nuclear energy’s difficult legacy for future generations to deal with. So we need to build a safe and secure repository as soon as possible. We should not operate the existing interim storage facilities any longer than necessary.

What risks are posed by the interim storage facilities for spent fuel elements and high-level radioactive waste?

These interim storage facilities are licensed for 40 years. Let’s take the Gorleben site as an example: its operating licence is due to expire in 2035. The other 15 interim storage facilities will follow soon afterwards. But Germany won’t have a repository for high-level radioactive waste by then. This raises a host of questions. What will happen to the waste that is stored at these sites? What condition will the fuel elements be in? How reliable are the sealing and monitoring systems? These things are impossible to predict. So the Oeko-Institut is demanding continuous monitoring, which must include periodically opening and examining a number of sample storage containers. If we intend to store high-level radioactive waste in a repository, we first need to find an answer to the question whether the condition of the containers and their contents will allow this to take place without any need for additional safeguards.

Do the current interim storage facilities have adequate capacity? Will they be able to cope with the forthcoming decommissioning programmes?

The interim facilities have sufficient capacity to store spent fuel elements and high-level radioactive waste, but not enough to store the low- and intermediate-level radioactive waste that forms the bulk of the waste produced during decommissioning, mainly from power plant buildings and technical components. So we will need additional interim storage facilities at the reactor sites. A repository for this type of waste is now being built at Konrad pit, and it is important that it comes into operation as soon as possible.

What are the criteria that should be met by a future final storage facility?

The key criterion is that no water should penetrate the facility, so the host rock must be as watertight as possible. The containers and backfilling must be constructed in such a way that the waste is stored securely, with no leaks, until the surrounding rock closes the gap. So the construction of the containers must be very solid. They should not corrode easily and they should not react with the stored materials. In order to protect the repository from water penetration, the entire facility must also be closed and filled with effective barrier materials. We also need a clearly structured emplacement geometry and clear documentation of the facility. If the repository needs to be reopened again at any stage – for example, if the waste needs to be removed from the facility, which is not something we expect to happen – it must be clear which type of waste is being stored and precisely where it is located at the site.

How can a balance be achieved between integrity and recoverability?

The best approach – should it be necessary to remove the waste from the facility in future – is to build a new facility directly adjacent to the sealed repository from which storage containers are to be removed. This approach allows safe, secure and timely sealing of the repository while allowing possible access at a later stage, if necessary. This also has implications for the search for a site: there needs to be enough space not only for the repository itself but also for the possible future construction of a back-up facility in the host rock.

Thank you for talking to eco@work.

The interviewer was Christiane Weihe.