The restart of the neutron source at the research reactor in Garching has been delayed again. As reported by the Technical University of Munich as the operator of the FRM II on Friday, a small amount of water escaped from the compensators in the central channel in the reactor basin, in which a fuel element is located. However, the incident had no impact on the safety of the neutron source, the operating personnel or the environment; it says on the part of the TU. No radioactivity was released either.
According to the TU, an early warning system reported the leakage of a small amount of liquid on Wednesday. Tests initiated as a result, including with an underwater camera, revealed a hole in one of the compensators, a kind of vacuum barrier chamber, on the underside of the central duct. The central channel separates the primary cooling circuit, i.e. conventional water from the reactor pool, from that in the so-called moderator tank, which contains heavy water, deuterium oxide.
In order to repair the damage, the central channel should now be removed and replaced. After the exchange, the TÜV must check the system extensively; only then is it possible to resume reactor operation. A spokeswoman for the FRM II told the SZ on Friday that it is hoped that a cycle of 60 days of neutron production will still be possible this year.
The research neutron source in Garching is considered one of the most powerful of its kind. However, the research reactor has been criticized because it is operated with highly enriched uranium. Environmentalists are therefore demanding its shutdown, and a lawsuit is pending before the Bavarian Administrative Court. After a malfunction in early 2020, during which a small amount of radioactive carbon dioxide escaped into the air, and as a result of the corona pandemic, the research reactor has been idle for almost two years.
The Greens are once again calling for the final shutdown
In view of the new damage, the two Greens members of the state parliament, Claudia Köhler and Markus Büchler, are again calling on the state government to prevent the reactor from restarting until an operating concept with less enriched uranium has been found. Interim storage must also be clarified. The cooldown pool on the FRM II is almost full. According to the contracts, the spent fuel elements are to be transported to the nuclear waste interim storage facility in Ahaus, North Rhine-Westphalia. However, two permits are still missing.
The approval process is quite complex: The operators of the FRM II give their documents to the federal company for interim storage (BGZ), which since 2019 has managed the two large interim storage facilities in Ahaus and Gorleben, the decentralized interim storage facilities at the sites of the German nuclear power plants and twelve storage facilities with weak – and medium-level radioactive waste. On behalf of the reactor operator, the BGZ in turn applies for the necessary storage license for the fuel elements of the FRM II in Ahaus from the responsible Federal Office for the Safety of Nuclear Waste Management (BASE). This approval process is already well advanced, says a spokesman for the BGZ.
Because the requirements for protecting the interim storage facility against attacks from outside have changed, documents on IT security still have to be submitted. However, the BGZ assumes that it will be able to submit these in a timely manner. If all documents are available, the BASE can start its examination. At the same time, the operators of the Garching research reactor apply for the necessary transport permit from the Federal Office via a specialized transport company.