Germany’s Federal Company for Radioactive Waste Disposal (BGE – Bundesgesellschaft für Endlager mbH) said it has “made a lot of progress in its preparation for the retrieval of radioactive waste from the Asse II mine”. An exploratory drilling at a depth of 750 metres has provided information for the first time about the condition of the stored barrels in Storage Chamber 12.
“Through a hole the size of a tennis ball, we were able to take a look into Storage Chamber 12 for the first time in decades,” said Iris Graffunder, chairwoman of the BGE management board. “Our first impression is that at least the visible barrels are in good condition. Now we’re going to figure out exactly how the chamber atmosphere is made up and we’re going to measure the activity levels in the chamber. For this we need more space and have to expand the borehole even further.”
The ageing nuclear waste facility in the Asse II salt mine near Wolfenbüttel in Lower Saxony holds some 126,000 barrels of low- and intermediate-level radioactive waste, is operated by BGE a federally owned company within the remit of the Federal Environment Ministry. In April 2017, BGE took over responsibility as operator of the Asse II mine and the Konrad and Morsleben repositories from the Federal Office for Radiation Protection.
From 1967 to 1978, around 47,000 cubic metres of low- and intermediate-level radioactive waste were emplaced in the mine according to information from former operator, the Association for Radiation Research (now known as Helmholtz Zentrum München, HMGU). Some 67% of the waste originated from NPPs. Typical waste included: filters, scrap metal, paper, laboratory waste, building rubble, wood, slurries and mixed waste. Other waste was delivered by research institutes, the nuclear industry and other waste producers such as the medical industry.
The radioactive waste was emplaced in 13 former mining chambers took place in 1973 and 1974. Two chambers are located in the central section and 10 in the southern flank of the mine at depths of 725 and 750 metres. A further chamber is located at the 511-metre level. Chamber 12 holds 7,464 containers, of which 6,747 are barrels and 717 are so-called lost concrete shields. The containers were stacked lying down.
Storage Chamber 12 is one of the highest radon emitters in the Asse II mine. At the end of May 2024, miners started the targeted drilling into the Storage Chamber 12 under the highest radiation protection requirements. A hole around 117 metres long was drilled at a depth of 750 metres to get into the chamber. Earlier in August, radiation protection measurements during drilling showed an increased radon level, indicating that the chamber was reached.
A planned gas measurement will show how the chamber atmosphere is composed and what influencing factors determine it. Geological exploration is also ongoing. Preliminary investigations revealed that the ceiling of the chamber was lower than expected. The first images from the chamber confirm these radar and magnetics measurements. A planned 3 D scan is expected to provide a more complete image of the emplacement chamber.
All of the measured values obtained will be utilised in the further planning of retrieval and in future licensing procedures. Among other things, they will allow BGE to determine which recovery technologies can be used in Storage Chamber 12.
According to current laws and state of the art of science and technology, the final disposal of radioactive waste in the manner employed at the Asse II mine would not be eligible for a licence although no laws were broken based on the legislation in force at the time. If the waste were to remain in the mine, it would not be possible to demonstrate that the legal safety objectives would be met and the intention is for the waste to be retrieved. Removal is not expected to start before 2033 as scientific methods to do it safely are still being investigated.
According to current planning, retrieval of the radioactive waste stored in Asse II is scheduled to begin in 2033. Currently, costs of about €4.7bn ($5.5bn) are expected until retrieval begins, including the costs of keeping the mine open and implementing the emergency planning precautions. The cost of retrieval, interim storage, and final disposal after 2033 are not included.
