What about the safety of interim storage facilities?
- The technical concept of dry interim storage with transport and storage casks and an interim storage building has proven its worth. In over 25 years of operation, no malfunctions have occurred that might have posed a hazard to people or the environment.
- The transport and storage casks are the central component of safe interim storage. The design of the storage buildings and their technical facilities are also a guarantee of safety during interim storage. This security concept is supplemented by administrative precautions, such as comprehensive property protection.
- This concept of interim storage in Germany ensures that all the following protection targets are met in the long term:
– Safe confinement of radioactive waste
– Heat dissipation
– Radiation shielding
– Prevention of a nuclear chain reaction in the cask - The transport and storage casks we use have proven themselves over decades. The casks have two lids and this double lid system guarantees the safe confinement of the radioactive contents. The casks are permanently monitored for the slightest amount of leakage during interim storage. The fuel element support baskets inside the casks enable heat dissipation and, in particular, prevent a nuclear chain reaction of the fissile material contained in the fuel elements. The casks are designed to withstand even extreme events such as transport accidents, fire or an aircraft crash. They fully meet the strict requirements of the International Atomic Energy Agency (IAEA).
- All the casks have successfully completed an extensive test programme at the Federal Institute for Materials Research and Testing (BAM) and are approved for transport and storage in accordance with international regulations. The seals of the cask lids have also remained tightly closed to this day. Ongoing long-term tests on cask seals are carried out to ensure that the safe use of the sealing systems will be guaranteed well beyond the approved period.
- Following the reactor accident in Fukushima, the Nuclear Waste Management Commission (ESK) used a stress test to evaluate the robustness of the interim storage facilities against impacts that exceeded the requirements of the licensing procedure. Earthquakes, floods, heavy rains, fires, aircraft crashes and other possible events were considered. In all scenarios, the interim storage concept met and fulfilled the stress level, with the result that the ESK certified the interim storage facilities to be highly robust even under conditions beyond the design basis, i.e. in case of stress levels that are higher than the design would normally permit.
- The safety of interim storage is continuously monitored by the supervisory authorities of the federal states. A comprehensive safety review (periodic safety review, PSR) is also carried out every ten years, pursuant to §19a of the Atomic Energy Act.
- The operator must regularly inspect all safety-relevant components in the presence of an expert appointed by the supervisory authority and repair or replace them where necessary. This ensures the operational readiness and functionality of all the interim storage system’s relevant components.
- The operation of interim storage facilities is carried out exclusively based on an operating manual reviewed and approved by the supervisory authorities. The operating personnel must possess the required levels of technical knowledge and reliability and prove this to the supervisory authorities.
What is the situation regarding radiation?
- The transport and storage casks are designed in such a way that they already fulfil all protective functions. This means that no radioactive substances are released into the environment, and only a tiny fraction of the original gamma and neutron radiation is emitted to the outside world. Extensive testing has shown that the casks retain their contents safely, even in the case of bad accidents and serious external influences. The sealing of the casks is also constantly monitored during the entire interim storage period.
- At the Ahaus and Gorleben interim storage facilities, the radiation (the ambient dose rate) is permanently measured and monitored – and samples from air, precipitation, soil, groundwater and vegetation are regularly tested for radioactive substances. Regular evaluation of these samples from the environment has revealed that no radioactivity originates from the operation of the interim storage facilities. Since 1983, extensive measurements have been carried out at the Gorleben interim storage site in accordance with strict specifications. In 2016, an annual value of 0.18 millisieverts (mSv) was measured at the fence of the interim storage facility, the location with the highest ambient dose rate. If a person remained constantly at this fence for one year, they would receive this dose. In comparison: On a flight from Frankfurt to San Francisco, passengers receive approx. 0.1 mSv and during an X-ray of the thoracic spine the dose involved is approx. 0.3 mSv. A change of residence from northern Germany to a German low mountain range means an additional dose of approx. 0.18 mSv per year. No dose was detected 200 metres from the Gorleben interim storage facility; the closest location to the interim storage facility, the village of Gorleben, is two kilometres away. At the Ahaus interim storage facility, no contribution from the stored inventory has been detected at the fence, only natural radiation.
How do the fuel elements behave in the cask?
- To date, the interim storage of fuel elements has shown that the technical concept functions in a problem-free manner. The ageing behaviour of fuel elements under the conditions of dry interim storage is also studied in international programmes. For example, laboratory tests and individual demonstration programmes with loaded casks are being prepared in the USA, Japan and Korea – including the accompanying measuring programmes, investigations of reference fuel rods and final inspections. In the past, a loaded CASTOR® cask was opened and inspected in the USA after 15 years. The fuel elements and the cask itself were in perfect condition. However, investigations will continue in this respect.
What are the implications of the Brunsbüttel judgment?
- In 2004, a local resident filed a suit against the storage permit for the Brunsbüttel interim storage facility issued under the 2003 Atomic Energy Act in the Higher Administrative Court of Schleswig. This suit was followed by many years of litigation. With its decision of 19 June 2013, the Schleswig Higher Administrative Court revoked the storage permit of 2003. The judgment became legally binding with the decision of the Federal Administrative Court on 8 June 2015.
- However, these court decisions did not identify any safety deficits at the Brunsbüttel interim storage facility. The courts have still not ruled on the actual safety of the interim storage facility. At that time, the Federal Office for Radiation Protection was the responsible authority – and it was criticised for not being able to demonstrate to the court in the desired level of detail (due to confidentiality obligations) that the licence for the Brunsbüttel interim storage facility actually guaranteed protection against disruptive measures or other actions by third parties. A new permit for the site’s interim storage facility was applied for on 16 November 2015. The storage of fuel elements is tolerated on the basis of a nuclear regulatory order issued by the competent supervisory authority. There are no findings available that call into question the legally binding permits of all the other central and decentralised interim storage facilities.
What happens if a cask does develop a defect?
- The transport and storage casks in the interim storage facility are sealed with two lids (primary and secondary lids). Safe sealing and enclosure are already permanently guaranteed by just one of these lids. A pressure switch installed in the outer lid (secondary lid) permanently monitors overpressure in the sealing chamber between the two lids, thus monitoring the leakproof sealing of the entire lid system. Even the pressure switch itself is monitored by a self-monitoring system. If a leak is detected, the seal of the outer lid of a cask loaded with fuel elements can be easily replaced on site in the storage facility. If the primary lid develops a leak, an additional cover is welded on to the primary lid by means of a BAM-approved procedure, completely restoring the double lid function. A hot cell in which both lids can be remotely removed is not required.
Is there a system for managing ageing fuel elements?
- All interim storage facilities are subject to systematic ageing management measures. These measures are carried out in accordance with the guidelines of the independent Nuclear Waste Management Commission. These guidelines also ensure that all the exchangeable cask components (e.g. pressure switches, metal seals, trunnions, screws) are always available in sufficient quantities.
Is there a strategy for dealing with radioactive waste?
- The National Waste Management Programme of 2015 – drawn up with the participation of the public – defines Germany’s strategy for managing radioactive waste. The programme states that fuel elements in Germany must be placed in dry interim storage until their final disposal. This means that after several years of decay storage in the wet storage facility of a nuclear power plant, the irradiated fuel elements are loaded into CASTOR® transport and storage casks and stored in the interim storage facility on the site of the nuclear power plant until their final disposal. Sufficient interim storage capacities are available in Germany for this purpose.
- In accordance with the Site Selection Act, a site for a repository for heat-generating waste (essentially spent fuel elements) will be specified in 2031. The repository will then be approved and constructed and is expected to go into operation around 2050. In accordance with the National Waste Management Programme, an incoming storage facility will be constructed at the site of the repository. This facility will be approved with the first partial approval of the repository, i.e. at the beginning of the 2040s. This will enable the clearance of the interim storage facilities to begin before the final storage facility is put into operation.
- On 1 August 2017, the BGZ took over the Ahaus and Gorleben interim storage facilities and has guaranteed their safe operation since that date. In a next step from 2019, the BGZ will take over the twelve decentralised interim storage facilities for spent fuel elements at the sites of the German nuclear power plants. On 1 January 2020, the BGZ will also take over the twelve storage facilities for low and intermediate-level radioactive waste at the nuclear power plant sites. When all the sites have been integrated, the BGZ will create a comprehensive inventory of the overall situation, taking into account each individual interim storage facility and subsequently coordinate the next steps with the Federal Ministry for the Environment based on the BGZ’s inventory. There is sufficient time to carry this out until the respective approvals expire – and the BGZ will make the best possible use of this period with the help of external experts.