About Project

The PURL Initiative - the Polish Underground Research Laboratory - is a joint effort by scientific and research institutions designed to address the needs of the national economy and sustainable development. Its goal is to continue and expand research on deep geological storage that began in Poland in the late 1990s, with the support and guidance of government agencies responsible for the safe management of radioactive waste. Conducting systematic and coordinated research is the foundation for future decisions, which can thus be made based on well-established knowledge.

The following participated in the project:

 

Current Activities

Polish Nuclear Power Program (PPEJ) was approved.

On January 28, 2014, the Council of Ministers adopted the Polish Nuclear Power Program. This decision marks the culmination of a labor-intensive period of preparation and consultation on the Program, reaffirming the intention to implement nuclear power in Poland.

Among other things, the program includes guidelines for the management of radioactive waste and spent nuclear fuel. Attention to these issues in the nuclear industry is particularly important, as reflected in the provisions of the adopted document - awareness of and responsibility toward people and the environment will accompany the investment process from the very beginning.

This relates in particular to safety requirements concerning the storage of long-lived waste - including highly radioactive waste and spent nuclear fuel - not only from nuclear power plants, but also from research reactors, industry, and medicine.

According to the plan, research in this area will be conducted in a coordinated manner, as discussed in greater detail in the quoted passage:

“Following the adoption of the PPEJ Program, it is planned that the Ministry of Economy, the Polish Geological Institute, and other interested institutions will sign an agreement to support the concept of deep geological disposal of radioactive waste through the construction of the Underground Research Laboratory (PURL).

The purpose of the agreement is to:

1.  Support scientific research aimed at improving deep geological storage techniques and identifying the geological conditions that ensure safe storage in deep geological formations, while also contributing to the development of the scientific workforce and technologies necessary to carry out future work.

2. To ensure the coordination of this work in Poland.

3. To make maximum use of international experience regarding the geological storage of radioactive waste.

4. To provide the public with objective information on geological storage.

5. Supporting the establishment of the Underground Research Laboratory (PURL).

6. Supporting the operations of the PURL, which is organizationally located within the Polish Geological Institute (PGI).

7. Utilizing the PURL’s experience and transforming it into an entity responsible for the preparation and construction of a deep geological storage facility.

The goals of PURL are:

• Coordinating work in Poland and compiling its results;
• International cooperation;Conducting scientific research;
• Expanding knowledge about the geology of potential storage sites;
• Promoting public awareness and transparency of activities;
• Preparing personnel and organizational structures for the operation of the storage site.

The research findings collected will be used in the future to identify a site and construct a deep geological repository for spent nuclear fuel and high-level radioactive waste.

The issue of spent nuclear fuel from research reactors was resolved in 2009 through agreements with the United States and the Russian Federation to export this fuel to the Russian Federation, as a supplier of fresh fuel. However, based on the experience of other countries, the need to build a spent nuclear fuel repository will arise approximately 30-40 years after the first nuclear power plant begins operation, which means no earlier than around 2050. Until then, spent nuclear fuel will be stored on the power plant premises, including in in-reactor storage pools. Although Poland has up to 50 years to commission such a repository (counting from the commercial commissioning of the first unit of the first nuclear power plant in 2024), the experience of other countries indicates the need to begin preparations well in advance. At this stage of the work, however, no options (including rock formations) for the construction of a spent nuclear fuel repository should be ruled out.”

We encourage those interested to read the entire document, which is available on the Ministry of Economy’s website:

www.mg.gov.pl 

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EU regulations governing the deep storage of radioactive waste adopted in Poland

On November 5, 2013, the Polish government adopted a draft amendment to the Atomic Law, related, among other things, to the storage of radioactive waste (as reported by some media outlets: www.nettg.pl.)

The proposed amendment transposes into national law European Directive 2011/70/EURATOM of July 19, 2011, establishing a Community framework for the responsible and safe management of spent nuclear fuel and radioactive waste.

The directive clearly identifies underground repositories - that is, geological barriers - as the safest solution for the disposal of high-level radioactive waste and spent nuclear fuel. The explanatory statement to the project notes that, in light of plans to build nuclear power plants, this issue is becoming increasingly relevant in Poland, and work on such a repository should begin as soon as possible, as it will take many years to complete. This solution must also address highly radioactive waste from other sources within Poland’s economy.

The adoption of these legal regulations is yet another argument supporting the validity of the initiative and the implementation of the PURL project.

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1st Conference of the PURL Underground Research Laboratory

On October 28, 2013, a conference marking the launch of the PURL program was held at the headquarters of the Polish Geological Institute - National Research Institute (PGI) in Warsaw at 4 Rakowiecka Street.

The conference was opened by PGI-NRI Director Prof. Jerzy Nawrocki, who emphasized that the role of PGI-NRI is to coordinate and assist in organizing the work, and that the presented project is inter-institutional in nature.

The speech by the Government Plenipotentiary for Nuclear Energy, Deputy Minister of Economy Ms. Hanna Trojanowska, addressed the status of the Polish Nuclear Power Program and, as was clearly emphasized,the necessity of beginning preparatory work under the PURL project, even though the potential need for spent fuel storage may not arise until after 2050. Dr. Henryk Jacek Jezierski, Chair of the PURL Program Council, discussed the tasks and expectations for PURL.

During the discussion session:

Grzegorz Ryżyński, M.A., from PGI-NRI presented global experiences in the construction of deep repositories for radioactive waste and spent nuclear fuel, as well as in the operation of underground research laboratories, known as URLs,

and Dr. Leszek Lankof from the Mineral and Energy Economy Research Institute of the Polish Academy of Sciences presented Polish experiences and research related to the underground disposal of radioactive waste and spent nuclear fuel.

The conference concluded with a discussion led by Dr. Henryk Jacek Jezierski on cooperation in developing the concept for a Polish geological repository.

Approximately 40 people attended the conference.

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Second Meeting of the Program Council of the PURL Underground Research Laboratory

On October 28, 2013, at the headquarters of the Polish Geological Institute - National Research Institute (PGI-NRI) in Warsaw, located at 4 Rakowiecka Street, the second meeting of the Program Council of the PURL Underground Research Laboratory was held.

Following a presentation by Mr. Zbigniew Kubacki, Director of the Department of Nuclear Energy at the Ministry of Economy, on the current status of work on the strategic document “Polish Nuclear Power Program,” the Council discussed possible scenarios for the Program’s development and the role of issues related to geological disposal within it. PURL’s work should be aligned with the pace of implementation of the Polish Nuclear Power Program, particularly regarding the selection of appropriate public communication methods and the need for discussions on the safety of its implementation.

Based on the introductory material prepared by the Council Chair, the Council discussed the concept for the future operation of PURL. Noting the existence of far-reaching plans for the construction and operation of a repository and recognizing that a necessary preliminary step is the creation of a Polish URL - that is, a field research laboratory - the Council focused at this meeting on evaluating the actions taken (particularly the launch of the website and the organization of the first PURL conference).

As an immediate priority, the Council recommended:

• developing a detailed PURL action plan that outlines the direction of research efforts, such as establishing criteria for the siting of storages;
• Collecting proposals for research tasks related to geological storage (as the first stage in developing the program);
• increasing the participation of Polish researchers in international programs and considering the formation of a research consortium to enable applications for European funding.

The Chair announced the launch of the PURL website and asked Council members to submit information about their activities, organized meetings, etc., for publication on the PURL website. The website is intended to serve as a platform for exchanging information on geological storage.

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First Meeting of the Program Council of the PURL Underground Research Laboratory

On May 20, 2013, the inaugural meeting of the Program Council of the PURL Underground Research Laboratory was held at the headquarters of the Polish Geological Institute - National Research Institute (PGI-NRI) in Warsaw, at 76 Jagiellońska Street.

The Director of PGI-NRI, Prof. Jerzy Nawrocki, Ph.D., welcomed the attendees and presented letters of appointment to the selected members of the Program Council. In accordance with Order No. 21 of the Director of PGI-NRI dated May 10, 2013, the Council consists of the following individuals:

• Prof. Andrzej Chmielewski, PhD, DSc, Eng.
• Andrzej Cholerzyński, MSc, Eng.
• Prof. Janusz Janeczek, PhD, DSc
• Henryk Jacek Jezierski, PhD
• Zbigniew Kubacki, MSc
• Prof. Eugeniusz Mokrzycki, PhD, DSc, Eng.
• Prof. Grzegorz Pieńkowski, PhD, DSc
• Janusz Włodarski, MSc, Eng.

Dr H. Jezierski was unanimously elected Chair of the Council, and Dr. hab. Grzegorz Pieńkowski, Associate Professor at PGI-NRI, was unanimously elected Secretary of the Council.

Dr H. Jezierski presented the concept of establishing the Polish Underground Research Laboratory (PURL). The purpose of establishing PURL is to address the issue of radioactive waste and to prepare for the construction of a repository for such waste.

History of Research in Poland

A research program for a deep geological repository had already been carried out in Poland. It was launched in connection with the construction of the Żarnowiec nuclear power plant in the 1980s, but was terminated when construction of the plant was suspended in 1990.

At that time, Central Research and Development Program (CPRB) No. 5.1.0, Objective No. 47, “Underground Repository for Radioactive Waste,” was established. As part of this program, the following studies were conducted:

1.Inwentaryzacja złóż soli formacji cechsztyńskiej mioceńskiej w wysadach solnych i w złożach pokładowych pod kątem ich przydatności dla składowania odpadów promieniotwórczych. Państwowy Instytut Geologiczny (PIG) 1988.

2.Kryteria przyrodnicze, technologiczne i ekonomiczno-społeczne wyboru lokalizacji podziemnego składowiska otworowo-ługowniczego w złożach soli kamiennej. - Chemkop, 1988.

3.Koncepcja podziemnego składowiska odpadów promieniotwórczych w wysadach solnych. Akademia Górniczo Hutnicza (AGH), 1988.

4.Studium struktur tektonicznych przy pomocy technik teledetekcyjnych i geofizycznych w rejonie wstępnie projektowanego podziemnego składowiska na odpady promieniotwórcze w pokładowym złożu soli kamiennej Mechelinki, woj. gdańskie. PIG, 1988.

5.Wstępne rozpoznanie stanu zaludnienia i zagospodarowania przestrzennego rejonu Mechelinki. Uniwersytet Adama Mickiewicza, Poznań 1988.

6.Studium wyboru lokalizacji i zakresu badań dla zaprojektowania budowy składowiska odpadów promieniotwórczych. Synteza studium. PIG, 1988.

7.Studium struktur tektonicznych przy pomocy technik teledetekcyjnych i geofizycznych w rejonie wstępnie projektowanych lokalizacji podziemnego składowiska w pokładowych złożach soli kamiennej. PIG, 1989.

8.Analiza materiałów geologicznych, geofizycznych, laboratoryjnych oraz analizy geochemiczne prób z wierceń archiwalnych na wysadzie Łanięta. AGH, 1989.

9.Analiza materiałów geologicznych, geofizycznych, laboratoryjnych i analizy geochemiczne prób z wierceń archiwalnych wykonanych na wysadzie Damasławek oraz opracowanie projektu głębokiego wiercenia do 1000 m. PIG, 1989.

10.Analiza i zestawienie wyników badań z uwzględnieniem obowiązujących kryteriów wyboru lokalizacji. PIG, 1989.

11.Informacja o pracach w zakresie wyboru obszarów i środowisk dla składowania odpadów promieniotwórczych w Polsce. PIG, 1989.

12.Studium struktur tektonicznych w otoczeniu wysadu solnego Damasławek przy pomocy technik teledetekcyjnych i geofizycznych. PIG, 1990.

In 1997, Poland signed the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management, which requires compliance with the fundamental safety principles set forth in documents developed by the International Atomic Energy Agency (IAEA) in Vienna.

Between 1997 and 1999, the Council of Ministers established the “Strategic Government Program (SPR) on Radioactive Waste and Spent Nuclear Fuel Management.” The President of the National Atomic Energy Agency (PAA) served as the supervisory body for the implementation of the SPR. The program’s objectives included drafting amendments to regulations, identifying potential repository sites, and developing an information policy. The SPR also included the task of “Selecting a site and developing a concept for a radioactive waste repository in deep geological formations.”

As part of the SPR, studies were conducted on deep geological storage, among other topics:

1.Opracowanie i zbadanie nowych sztucznych barier ochronnych, zapobiegających migracji najbardziej toksycznych radionuklidów ze składowiska odpadów promieniotwórczych. ICHiTJ, 1999.

2.Poszukiwania i charakterystyka materiałów naturalnych do budowy zewnętrznych barier składowiska odpadów promieniotwórczych. PIG, 1999.

3.Uzupełniające rozpoznanie wysadu solnego Damasławek. AGH, 1998.

4.Analiza wyników prac laboratoriów światowych dla głębokiego Składowiska Odpadów Promieniotwórczych pod kątem ich przydatności dla rozwiązań krajowych. Instytut Gospodarki Surowcami Mineralnymi i Energią (IGSMiE) PAN, 1998.

5.Analiza materiałów archiwalnych dotyczących struktur skalnych na Niżu Polskim pod kątem przydatności do lokalizacji głębokiego Składowiska Odpadów Promieniotwórczych. IGSMiE PAN, 1998.

6.Rozpoznanie budowy wewnętrznej czapy gipsowo-anhydrytowej wysadu solnego "Damasławek" płytkimi badaniami sejsmicznymi. PIG, 1999.

7.Ocena możliwości głębokiego składowania odpadów promieniotwórczych w skałach ilastych monokliny przedsudeckiej w rejonie Jarocina - Pogorzeli. IGSMiE PAN, 1999.

8.Opracowanie modelu koncepcyjnego krajowego głębokiego składowiska odpadów promieniotwórczych w skałach: a) solnych b) ilastych. IGSMiE PAN 1999.

9.Opracowanie projektu koncepcyjnego Podziemnego Laboratorium Badawczego (PLB) w wysadzie solnym Kłodawa. IGSMiE PAN, 1999.

 

As a result of SPR’s work, it was determined that the site selection process is lengthy and multi-stage, and is based on selection by elimination of available geological formations. The selection criteria were based on the assumptions that the geological structure should be characterized by:

• appropriate dimensions,
• a homogeneous and simple structure,
• impermeability ensuring no water flow,
• resistance to deformation,
• stability throughout geological history,
• and the absence of seismic activity.

As a result of the analysis, existing deep mines were eliminated as potential sites due to water-related hazards, reduced rock mass stability, de-fracturing resulting as a side effect of mining operations, proximity to other mines, and seismic activity. A preliminary analysis was conducted on 44 sites (17 metamorphic and igneous rocks, 7 clay formations, and 20 salt deposits).

The following were identified as promising:

• crystalline rocks of the East European Platform in northeastern Poland (considered reserve sites due to limited hydrogeological data),
• clayey rocks of the Pre-Sudeten Monocline near Jarocin - an Upper Triassic complex where geophysical surveys identified optimal locations,
• salt intrusions (selected): Damasławek, which has been surveyed in detail, and Kłodawa and Łanięta, identified based on an analysis of archival materials.

 

A study conducted in 2011 by the Mineral and Energy Economy Research Institute (Polish Academy of Sciences) „Przegląd, ocena i ustalenie możliwego zakresu wykorzystania opracowań (projektów, analiz, ekspertyz) w zakresie postępowania/gospodarowania odpadami promieniotwórczymi i wypalonym paliwem jądrowym” included:

1.Identification of the scope of studies conducted to date in Poland.

2.An assessment of the results of previous studies conducted, among other things, for the design and construction of the Żarnowiec Nuclear Power Plant, taking into account the conditions prevailing during the implementation period and the results of activities related to the siting and design of radioactive waste repositories: surface and deep.

3.A summary of previous comparative cost analyses, depending on the fuel cycle solution recommended for Poland.

4.A summary of previous comparative cost analyses of radioactive waste and spent fuel management, depending on the reactor technologies recommended for Poland.

5.Comparison of methods for managing spent nuclear fuel for the fuel cycle options recommended for Poland - including technical, technological, and cost analyses - to establish criteria that facilitate the decision to adopt an open or closed cycle.

6.Preparation of a balance sheet for radioactive waste and spent nuclear fuel for the individual phases of the fuel cycle.

The main focus of this analysis was on the quantitative and cost aspects of radioactive waste management, with less emphasis on technological considerations.

This study indicated that:

“Among the claystone formations found in Poland, the Upper Triassic claystone complex in the Pre-Sudeten monocline (near Jarocin and Pogorzela) was deemed the most promising; in this complex, the upper gypsum layers lie at depths ranging from 500 to 1,000 m below ground level. The promising area, from the perspective of locating an underground waste repository with an area of approximately 20 km², is situated about 10 km southwest of Jarocin.

Within the salt structures, the salt intrusions of the Central Poland region - Damasławek, Łanięta, and the southern part of Kłodawa - were deemed the most favorable for the location of a deep storage. Locations in the northeastern part of Poland within crystalline rock massifs were considered backup options.„

Locations of rock formations identified for the construction of deep repositories for spent nuclear fuel and high-level radioactive waste. According to Mineral and Energy Economy Research Institute (Polish Academy of Sciences).

The work carried out by the Mineral and Energy Economy Research Institute (Polish Academy of Sciences) in Kraków, coordinated by J. Ślizowski, K. Ślizowski, and L. Lankof, focused primarily on the potential use of salt formations as a host rock for radioactive waste disposal. Within this research program, laboratory investigations were conducted on Zuber salts and clayey salt rocks, which constitute the principal components of the Zechstein salt diapirs in the Central Poland salt province. The investigations included:

1.Mineralogical and petrographic studies, including chemical analyses of Zuber salts, scanning electron microscopy (SEM), investigations of the mechanisms and rates of desiccation crack formation, and determination of moisture loss during thermal drying of Zuber salts.

2.Physical property testing, including measurements of porosity, density, permeability, and gas content.

3.Geomechanical testing, including strength, creep, and stress relaxation measurements.

4.Sorption studies of Zuber salts.

Based on these investigations, it was concluded that only part of these salt formations (specifically the brown Zuber salts) could be considered suitable for waste disposal.

One of the principal findings of these studies was that the investigated rocks exhibited a high capacity for radionuclide sorption, representing a significant advantage for repository applications.

The same research institute also investigated the suitability of clay formations as potential host rocks. The Keuper claystone-mudstone complex of the Fore-Sudetic Monocline was identified as a promising formation, and two candidate areas were selected: Jarocin and the area between Kępno and Wieruszów. In both locations, a homogeneous clay-rich sequence more than 200 m thick was identified at depths of approximately 450 - 500 m below ground level, overlain by a 300 m thick sandstone unit.

In the Jarocin - Pogorzela area, the Mineral and Energy Economy Research Institute (Polish Academy of Sciences) conducted additional investigations, including:

development of a database of geological and hydrogeological boreholes;geophysical surveys to refine the understanding of local tectonics and hydrogeological conditions;development of a hydrogeological model;assessment of environmental conditions, spatial planning constraints, and the socio-economic setting;preparation of a detailed geological investigation programme, including drilling activities;preparation of an application for a licence to conduct detailed geological investigations.

Despite these investigations, the authors themselves acknowledged that the existing level of site characterization in the Jarocin-Pogorzela area was clearly insufficient to support a decision on the construction of a deep geological repository.

For the Damasławek salt diapir, supplementary laboratory analyses of preserved salt samples were carried out, together with new geophysical investigations (geoelectrical, gravimetric, and shallow seismic surveys).

Two prospective areas suitable for the location of shafts and underground repository excavations were identified within the central part of the diapir.

Because of the significant differences in the physical and chemical properties of the selected host rock types, two conceptual models of a deep geological repository were developed: one for a clay-rock formation and another for a salt diapir. Both concepts considered the disposal of either spent nuclear fuel or vitrified high-level radioactive waste.

The proposed underground research laboratory (URL) in the Kłodawa rock salt mine may be regarded as the beginning of the Polish URL programme. The planned research was intended to focus on thermo-hydro-mechanical (THM) processes, excluding radiological and chemical effects. However, due to public opposition, the project was never implemented.

 

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This text is an adapted extract from a study by Dr. H. J. Jezierski titled “Concept for the Construction of a Deep Geological Repository for Radioactive Waste in Poland,” commissioned by the Department of Nuclear Energy of the Ministry of Economy, which holds the copyright to this text.

World Projects

The concept of deep geological repositories for radioactive waste originated in the 1950s, when the U.S. National Academy of Sciences proposed the underground disposal of radioactive waste generated by the military nuclear programme.

Research efforts subsequently led to the establishment of the U.S. Department of Energy's Waste Isolation Pilot Plant (WIPP) by the U.S. Congress in 1979. WIPP, located in New Mexico at a depth of approximately 650 m within Permian bedded salt formations, was developed as the first deep geological repository in the United States. Construction activities began in 1988 but were interrupted several times due to public opposition. The facility finally commenced waste acceptance in 1999. It should be noted that WIPP was designed specifically for the disposal of transuranic waste generated by the U.S. nuclear weapons programme.

The disposal of spent nuclear fuel at WIPP would require changes to U.S. legislation. In the United States, spent nuclear fuel and high-level radioactive waste were stored at 121 locations across the country. Based on data collected over a ten-year period, the U.S. Department of Energy identified ten candidate repository sites in six states in 1984. Following preliminary investigations, President Ronald Reagan approved three sites for detailed characterization: Hanford (Washington), Deaf Smith County (Texas), and Yucca Mountain (Nevada), located within a former nuclear weapons testing area. The U.S. Department of Energy initiated extensive investigations at Yucca Mountain to determine whether the geological formation could safely accommodate more than 70,000 tonnes of spent nuclear fuel for long-term disposal. The proposed repository host rock consisted of volcanic tuffs, a lithology that is generally uncommon for deep geological disposal because of its less favourable properties compared with other potential host rocks. Consequently, the site selection was influenced by factors beyond lithology alone.

In 1987, the U.S. Congress amended the Nuclear Waste Policy Act, authorizing detailed investigations exclusively at Yucca Mountain. In 2002, President George W. Bush approved the development of the repository. The U.S. Department of Energy had originally planned for the Yucca Mountain Repository (YMR) to begin accepting spent nuclear fuel in 1998; however, this target was not achieved. The delays resulted, among other factors, from public opposition, which influenced political decisions leading to reductions in the funding required for repository development.

During his 2008 presidential campaign, Barack Obama pledged to terminate the Yucca Mountain project. Following his election, funding for the programme was effectively discontinued by Congress. Nevertheless, many experts and policymakers in the United States continue to advocate for the continuation of the Yucca Mountain Repository. The U.S. experience demonstrates how easily deep geological repository projects can become highly politicized.

In contrast, the ONKALO repository in Finland has progressed without comparable political obstacles. The repository, intended for the disposal of spent nuclear fuel from Finnish nuclear power plants, is being developed by Posiva Oy, jointly owned by Fortum Oyj and Teollisuuden Voima Oyj (TVO), the operators of Finland's nuclear power plants. The Finnish Parliament ratified the Decision in Principle in 2001, formally approving the Olkiluoto site - adjacent to one of Finland's nuclear power plants - as the location for the repository. This decision was preceded by the construction of the ONKALO underground rock characterization facility.

According to the Finnish repository concept, spent nuclear fuel is encapsulated in corrosion-resistant disposal canisters and emplaced at a depth of several hundred metres. The annular space between the disposal canisters and the host rock is filled with highly compacted bentonite clay, which acts as an engineered barrier. According to information published by the Finnish Radiation and Nuclear Safety Authority (STUK), the development of the repository comprises five principal phases: pre-decision research and site investigations (1978 - 2001), repository design and construction of the underground rock characterization facility (2001 - 2014), repository construction (2014 - 2020), repository operation (2020 - 2120), and repository closure (2120 - 2125).

Sweden has also undertaken the development of a deep geological repository for spent nuclear fuel generated by its commercial nuclear reactors. In the early 1980s, Svensk Kärnbränslehantering AB (SKB) was established as the organization responsible for implementing Sweden's radioactive waste management programme. The proposed repository design is based on copper-coated disposal canisters containing spent fuel assemblies emplaced in deposition holes excavated in crystalline granite bedrock. The remaining void space is filled with bentonite clay, whose very low hydraulic conductivity and high swelling capacity provide an effective barrier to groundwater movement. In 2009, it was announced that the Swedish repository would be constructed near the Forsmark Nuclear Power Plant. At that time, completion of construction was provisionally anticipated around 2015. Although the project has experienced delays, repository implementation has continued through the licensing and construction phases.

 

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This text is an adapted extract from a study by Dr. H. J. Jezierski titled “Concept for the Construction of a Deep Geological Repository for Radioactive Waste in Poland,” commissioned by the Department of Nuclear Energy of the Ministry of Economy, which holds the copyright to this text.

Underground Laboratories

The process of constructing deep geological repositories should be distinguished from the facilities known as Underground Research Laboratories (URLs).

URLs have been established in most countries intending to build deep repositories for radioactive waste. Among the main tasks carried out by URLs are: determining the impact of waste emplacement on the environment, improving radioactive waste repository construction techniques, promoting knowledge about disposal, modelling geological barriers, verifying the correctness of engineering designs, investigating the effects of the Excavation Disturbed Zone (EDZ) resulting from mining works, etc.

It is expected that a URL should provide: 

• minimal and acceptable seismic hazard,
• limitation of waste contact with the biosphere over a period of thousands of years (through low rock permeability and the absence of groundwater or its very slow migration, as well as radionuclide sorption capacity).

The growing interest in radioactive waste disposal has contributed to the construction of underground laboratories and the implementation of national and international research projects.

Currently, there are 13 operating URLs worldwide, including 6 located in crystalline rocks, 4 in clay complexes, 2 in rock salt, and 1 in tuffs.

For several years, there has been a tendency toward cooperation between countries producing relatively small amounts of radioactive waste in order to construct a common regional radioactive waste repository. Currently, the SAPIERR (Support Action: Pilot Initiative for European Regional Repositories) programme, involving 21 organizations from 14 countries, is funded by the European Union.

Germany has experience in the construction of radioactive waste repositories. The Morsleben Repository for Radioactive Waste (Endlager für radioaktive Abfälle Morsleben - ERAM) is located in deep geological layers within the Bartensleben rock salt mine in Saxony-Anhalt. After salt mining operations ceased, the Bartensleben mine was designated by the government as a radioactive waste repository. Today, the facility is operated by Deutsche Gesellschaft zum Bau und Betrieb von Endlagern für Abfallstoffe mbH under the supervision of the Bundesamt für Strahlenschutz.

Salt mining in this region has a tradition of more than one hundred years. The first shaft, "Marie", was sunk in 1897. The "Bartensleben" mine began operation between 1910 and 1912. The mine is between 320 and 630 m deep. The initial enthusiasm regarding the construction of repositories in salt has, however, begun to decline with the emergence of new methods for investigating the stability of such repositories, due to the plasticity of salt. This property of salt, until recently regarded as an advantage, is now increasingly perceived in safety analyses as a hazard.

The French experience in radioactive waste disposal is also worth discussing. ANDRA, the French public organization responsible for managing the radioactive waste disposal process, has developed a methodology for repository construction. In developing this methodology, research carried out at the Meuse/Haute-Marne URL was used, where the Agency is preparing for repository operation in a clay formation.

The ANDRA methodology includes the following stages:

1. Identification of constraints and evaluation of appropriate solutions based on waste properties and geological conditions.
2. Identification of potential repository locations in deep geological formations.
3. Communication and relations with stakeholders as part of the decision-making process at national, regional, and local levels.
4. Geological investigations, simulation programmes, and modelling.
5. Construction and operation of the underground URL.
6. Technological development programmes.
7. Safety studies and preparation of applications for nuclear safety and radiological protection licences.
8. Construction of the repository.
9. Definition of the waste acceptance criteria package, disposal specifications, and inspection rules.
10. Detailed studies concerning operating conditions, reversibility, long-term monitoring, etc.
11. Cost assessment for the facility.

The schedule for implementation of the repository programme in France included:

• 1991 - adoption of the Waste Act, which established ANDRA, with responsibilities including research for the geological disposal of high- and intermediate-level radioactive waste.
• 1994 - 1996 - geological field investigations in Meuse and Haute-Marne in clay formations at a depth of 500 m below ground level. 1999 - repository construction licence.
• 2005 - report summarizing geological investigations.
• 2006 - second legislative approval of the geological repository (further legislative amendments were planned for 2016).
• 2009 - selection of the detailed site (30 km² out of the 250 km² investigated).
• 2010 - 2012 - geological investigations.
• 2013 - 2014 - public debate leading to government site selection.
• 2015 - licence to commence repository operation.
• 2017 - start of construction.
• 2025 - start of waste disposal.

The example of France shows how often legal regulations have been adapted to the needs of the project and how important public communication is during the implementation of such a project.

It should also be remembered that in France URLs are operated by two institutions: ANDRA and, separately, IRSN.

Under geological conditions similar to those in France, repository research is also being carried out in Belgium. The experience gained from the underground laboratory in Mol (Belgium) in clay formations over many years has confirmed the technological feasibility of disposal under such geological conditions. These studies demonstrated the advantages of these cohesive formations as disposal media. At the same time, because of the poor bearing properties of clay formations, they highlighted the need to pay particular attention to engineering solutions ensuring excavation stability.

It can be observed that, depending on geological conditions, countries conduct investigations in the most likely repository host formations available within their own geology. Thus, URLs have been established in Pinawa and Lac du Bonnet (Canada), Äspö HRL (Sweden), and Grimsel GTS (Switzerland) in crystalline rocks; in claystones at Mol (HADES) in Belgium and Bure URL in France; in salt at Asse Salt Mine, Gorleben (Germany), and Carlsbad, New Mexico (WIPP, USA); and in the previously discussed tuffs at Yucca Mountain (USA).

Outside Europe and the USA, Japan is at the forefront of URL research. The Horonobe Research Centre conducts research and development on the geological disposal of high-level radioactive waste and engineering research to verify the reliability of deep geological disposal under actual geological conditions.

The Horonobe Underground Research Laboratory (HURL) is a project of the Japan Atomic Energy Agency (JAEA) in northern Hokkaido and aims to investigate the geological environment in sedimentary rocks. HURL is one of the underground research laboratories planned under the Long-Term Programme for Research, Development and Utilization of Nuclear Energy (LTP). The role of underground research laboratories is defined in the LTP as providing facilities for research and development to confirm waste disposal technologies under geological conditions and to establish methods for safety assessment. The URL is also intended to serve as a demonstration facility for the public to improve understanding of the principles of geological disposal.

Operation of HURL is planned for a period of 20 years in three phases:

• Phase 1: Preliminary surface investigations (6 years).
• Phase 2: Underground access investigations (6 years).
• Phase 3: Investigations using the completed facility (9 - 11 years).

The results of research at HURL contribute to the development of the geological disposal programme and the preparation of safety regulations by the government. They are intended to be considered together with the results from subsequent Japanese URLs operated by JAEA (Tono Geoscience Center in Gifu Prefecture and Tokai Research and Development Center in Ibaraki Prefecture), together with the results of extensive international cooperation. An important element attracting attention because of future repository operational safety is research on the Excavation Disturbed Zone (EDZ) resulting from mining activities. Such investigations are carried out at many URLs. For example, at the Canadian URL at Lac du Bonnet, in areas of high in situ stress, damaged zones were found to extend several tens of centimetres, and maintaining excavation stability required sealing water inflows.

At Mont Terri in Switzerland, investigations in clay formations showed that clay minerals exhibiting plastic and swelling properties caused rapid healing of fractures formed within the EDZ. Similar investigations have been carried out in rock salt. Such studies make it possible not only to assess the depth of the EDZ in different rock types but are also used to select the best repository location and to minimize risks during repository operation. Another issue important for long-term repository safety investigated in URLs is the effect of heat generated by radioactive waste on the surrounding rock. Experimental studies have shown that heat generation significantly accelerates creep in rock salt, while in clay formations and fractured crystalline rocks it may cause significant movement of water and gases within the rock mass and alter the nature of fractures.

Research at URLs has also been directed towards evaluating the behaviour of bentonite buffer materials and repository backfill. In rocks other than crystalline rocks - that is, less consolidated formations - it has been established that a key issue is ensuring protection of excavations against rockfalls, collapse, creep, and convergence. In sedimentary formations, URLs have investigated the hazard of increased lateral groundwater migration resulting from the depositional and formation processes of these rocks. Studies concerning disposal in salt show that excavations in salt do not require additional support, but the issue of rock mobility remains. On the one hand, convergence processes have a positive aspect because they lead to complete (tight) isolation of the disposed waste, but on the other hand they may create safety problems due to the unpredictability of salt behaviour.

 

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This text is an adapted extract from a study by Dr. H. J. Jezierski titled “Concept for the Construction of a Deep Geological Repository for Radioactive Waste in Poland,” commissioned by the Department of Nuclear Energy of the Ministry of Economy, which holds the copyright to this text.

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