Activities for nuclear waste disposal development Jun 2020

Studies continue at the Meuse Haute-Marne laboratory, France
Source: Meuse Haute-Marne

Several nations are engaged in developing a deep geological disposal facility to isolate radioactive waste and used nuclear fuel in stable formations over extended time periods. An operating disposal facility satisfies both societal and industrial needs in terms of having a management strategy in place. The availability and suitability of igneous crystalline and volcanic rocks, argillaceous clay rocks and salts is being explored in many nations.⁽¹⁾ Though complex, the designing and construction of a geologic disposal facility (GDF) is founded on the knowledge and practical experience gained in the underground civil engineering and mining industries over hundreds of years.

The siting of a GDF is dependent on the prevailing geological conditions and their availability and suitability of the purpose with various exploratory investigative methods being used to gain the required scientific verification that host rocks are suitable for constructing the necessary or proposed facilities.

France

Starting in the early 1990s, the National Agency for Radioactive Waste Management (ANDRA) in France began to study the suitability of two rock types - argillite and granite. The stiff clay rock argillite is approximately 155 million years old and sits in the Callovo-Oxfordian area at a depth of 400m to 600m. Experiments at the Meuse Haute-Marne laboratory have generated scientific information to ensure that the clay layer of the Callovo-Oxfordian provides the desired properties for a disposal facility, with numerous deep bore-holes having been drilled since 1994. Commissioning of the proposed Cigéo geologic disposal facility is programmed to occur before 2035.

Underground geological laboratory,Japan
Source: Horonobe Underground Research Centre

Japan

The disposal facility in Japan is envisioned to be constructed in a stable rock formation more than 300m underground, with proposed host rock types to include crystalline and sedimentary rocks. While geologically and structurally comparable to similar terrains elsewhere in the world, the siting of a GDF in Japan is complicated by the seismic activity in the country. In 2017, Japan published a map of possible locations for the siting of a national nuclear geologic storage facility, based on a number of scientific characteristics and parameters . Tests have been conducted at a depth of 500m at the Horonobe Underground Research Centre, as well as at a depth of 1,000m in igneous rock at the Tona Geoscience Centre. Japan expects to initiate the site selection process in the later 2020s with start of operation project at 2040.⁽⁵⁾

Germany

The proposed disposal facility in Germany was to be sited initially at Gorleben. Exploratory activity performed at Gorleben were analyzed and their results published, confirming the potential suitability of the favorable properties of the rock salt formation at this location. Initial exploratory work at Gorleben began in 1979 with exploration drilling activities conducted over an area of about 300km² based upon results from seismic investigations in the 1930s and 1950s conducted by the oil and gas industry. Exploratory work continued at the site during a twenty-year period, concluding in 2000 when 11km of exploration boreholes and geotechnical wells were drilled to investigate the material and structural condition of the salt dome.⁽²⁾ However, with the adoption of the StandAG Repository Site Selection Act in 2014, the Gorleben site is to be treated like any other possible site in Germany during a new site selection process, which is expected be concluded in the early 2030s.

Salt mines considered for waste storage in Germany

United States of America

The proposed Yucca Mountain site for disposal of high-level, long-lived nuclear waste in the USA is often referred to as “the most studied piece of real estate on the plant.⁽³⁾ In 2002, then Secretary of State for Energy Spencer Abraham provided the USA Congress a comprehensive report providing extensive detail on the work conducted at Yucca Mountain, and voluminous Environmental Impact Statement. This report demonstrated that the proposed repository would have little to no adverse effect on future populations or the environment. Collected and analyzed data from some 8 miles (13km) of test tunnels and 450 boreholes drilled deep into the mountain were obtained to study the rock, water movement, and susceptibility to earthquakes of the proposed repository.⁽⁴⁾ The Yucca Mountain program ceased in 2009, by then President Obama. Under his direction, a Blue Ribbon Commission on America’s Nuclear Future was established and in 2012 it submitted its final report on recommendations for the USA nuclear waste management program. The next phase of the process is for the Administration of President Donald Trump and Congress to determine a path forward.

Site of the Yucca Mountain repository in Nevada, USA
Source: Horonobe Underground Research Centre

Scope of the projects

Exploratory activities at proposed GDF sites are providing a wealth of valuable scientific information and learning experiences. However, to ensure that proposed GDFs around the world are able to be constructed, it will require that this knowledge is retained and that related GDF projects have access to educated, creative and skillful practitioners over many decades. These construction projects will use modern technology and highly sophisticated equipment methodologies based on previous exploratory studies. Individuals with sought after skills will include, but is not limited to, those with knowhow to excavate into a host geology, prepare short and long-range plans and production sequences, select and schedule needed equipment, monitor the safety of personnel and equipment, and optimizing all site processes.

The scope of excavation work needed to establish the underground facilities required for the safe long-term disposal of the volume of high-level nuclear waste that already exists is on an expansive scale. With one repository currently nearing completion, and alternative disposal methods, such as deep horizontal boreholes, being developed, the future in nuclear waste management looks promising.