REGIONALNI PODZEMNI ISTRAŽIVAČKI CENTAR JOSEF

The Josef Gallery, located in the central Bohemia region of the Czech Republic was first excavated in 1981 as an exploration complex for the potential mining of gold. In 2007, the gallery was substantially reconstructed to house the Josef Underground Educational Facility (Josef UEF), which subsequently became an autonomous workplace under the direction of the Czech Technical University in Prague. At the beginning of 2010, the UEF was renamed the Josef Regional Underground Research Centre (Josef URC) which, along with the extensive underground complex, features modern above-ground facilities. One of the most important roles of this research center is to provide practical in-situ instruction in the fields of geotechnical engineering, geology, geochemistry, radiochemistry and radioecology. The training of future experts in this authentic underground setting involves the participation of several other Czech universities and numerous experienced specialists from outside the academic sphere. The IAEA (International Atomic Energy Agency) has added the Josef URC to its prestigious list of international training canters involved in the “Training in and Demonstration of Waste Disposal Technologies in Underground Research Facilities – A Network of Centers of Excellence” project.U rudniku Josef, čija je lokacija u centralnom području regije Bohemia, Češka, prva iskapanja su provedena 1981. u svrhu istraživanja za moguće vađenje zlata. Godine 2007. rudnik je znatno rekonstruiran da bi primio podzemni edukacijski objekt (PEO) Josef, koji je nakon toga postao zasebna jedinica pod upravom Češkog tehničkog sveučilišta u Pragu. Početkom 2010. PEO je preimenovan u Regionalni podzemni istraživački centar (RPIC) Josef koji, zajedno s velikom mrežom, podzemnih prostorija, predstavlja moderni istraživački objekt. Jedna od najvećih uloga ovog istraživačkog centra je praktična in situ obuka na polju geotehničkog inženjerstva, geologije, geokemije, radiokemije i radioekologije. Obuka budućih eksperata u ovom autentičnom podzemnom okolišu uključuje participaciju nekoliko drugih čeških sveučilišta i brojnih iskusnih specijalista van akademskih krugova. Međunarodna agencija za nuklearnu energiju (IAEA - International Atomic Energy Agency) dodala je Josef svojoj prestižnoj listi međunarodnih centara za obuku uključenih u projekt „Obuka i demonstriranje tehnologija za odlaganje otpada u podzemnim istraživačkim objektima – mreža centara izvrsnosti“ (Training in and Demonstration of Waste Disposal Technologies in Underground Research Facilities – A Network of Centers of Excellence)

TEHNOLOGIJA PRSKANE GLINE ZA DUBOKA ODLAGALIŠTA VISOKORADIOAKTIVNOG OTPADA

The sealing barrier will play very important role in the Czech disposal concept of high level radioactive waste. It follows Swedish SKB3 design where granitic rock environment will host the repository. Swelling clay based materials as the most favorable for sealing purposes were selected. Such clays must fulfill certain requirements (e.g. on swelling properties, hydraulic conductivity or plasticity) and must be stable for thousands of years. Better sealing behavior is obtained when the clay is compacted. Technology of the seal construction can vary according to its target dry density. Very high dry density is needed for buffer (sealing around entire canister with radioactive waste). Less strict requirements are on material backfilling the access galleries. It allows compaction to lower dry density than in case of buffer. One of potential technology for backfilling is to compact clay layers in most of the gallery profile by common compaction machines (rollers etc.) and to spray clay into the uppermost part afterwards. The paper introduces the research works on sprayed clay technology performed at the Centre of Experimental Geotechnics of the Czech Technical University in Prague. Large scale in situ demonstration of filling of short drift in the Josef Gallery is also mentioned.Brtvena barijera će igrati vrlo važnu ulogu u češkom konceptu odlaganja visokoradioaktivnog otpada. Ovaj koncept slijedi švedski SKB3 dizajn u kojem je odlagalište okruženo granitnim stijenama. Kao najpogodniji materijal za brtvljenje odabrani su materijali bazirani na bubrivim glinama. Takve gline moraju udovoljiti određenim zahtjevima (na primjer, značajke bubrenja, hidraulička vodljivost ili plastičnost) i moraju biti stabilne tisućama godina. Bolje brtvljenje postiže se ukoliko je glina zbijena. Tehnologija konstrukcije barijere može varirati prema ciljanoj suhoj gustoći. Vrlo visoka suha gustoća potrebna je za tampon (brtvljenje oko cijelog spremnika radioaktivnog otpada). Nešto su blaži zahtjevi glede materijala za ispunjavanje pristupne galerije. On omogućava zbijanje na nižu suhu gustoću nego u slučaju tampona. Jedna od potencijalnih tehnologija za ispunjavanje je zbijanje slojeva gline u većini profila galerije uobičajenim strojevima za zbijanje (valjci, itd.) i nakon toga prskati glinu u najgornji dio. Članak prikazuje istraživanje tehnologije prskane gline u Centru za eksperimentalnu geotehniku Tehničkog sveučilišta u Pragu. Također je spomenuta „in situ“ demonstracija zapunjavanja kratkog hodnika u Josef Galeriji

Experimental Verification of Amount of Water in Fully Saturated Bentonite

centrum experimentální geotechnik

SPRAYED CLAY TECHNOLOGY FOR THE DEEP REPOSITORY OF HIGH-LEVEL RADIOACTIVE WASTE

The sealing barrier will play very important role in the Czech disposal concept of high level radioactive waste. It follows Swedish SKB3 design where granitic rock environment will host the repository. Swelling clay based materials as the most favorable for sealing purposes were selected. Such clays must fulfill certain requirements (e.g. on swelling properties, hydraulic conductivity or plasticity) and must be stable for thousands of years. Better sealing behavior is obtained when the clay is compacted. Technology of the seal construction can vary according to its target dry density. Very high dry density is needed for buffer (sealing around entire canister with radioactive waste). Less strict requirements are on material backfilling the access galleries. It allows compaction to lower dry density than in case of buffer. One of potential technology for backfilling is to compact clay layers in most of the gallery profile by common compaction machines (rollers etc.) and to spray clay into the uppermost part afterwards. The paper introduces the research works on sprayed clay technology performed at the Centre of Experimental Geotechnics of the Czech Technical University in Prague. Large scale in situ demonstration of filling of short drift in the Josef Gallery is also mentioned

THE JOSEF REGIONAL UNDERGROUND RESEARCH CENTRE (JOSEF URC)

The Josef Gallery, located in the central Bohemia region of the Czech Republic was first excavated in 1981 as an exploration complex for the potential mining of gold. In 2007, the gallery was substantially reconstructed to house the Josef Underground Educational Facility (Josef UEF), which subsequently became an autonomous workplace under the direction of the Czech Technical University in Prague. At the beginning of 2010, the UEF was renamed the Josef Regional Underground Research Centre (Josef URC) which, along with the extensive underground complex, features modern above-ground facilities. One of the most important roles of this research center is to provide practical in-situ instruction in the fields of geotechnical engineering, geology, geochemistry, radiochemistry and radioecology. The training of future experts in this authentic underground setting involves the participation of several other Czech universities and numerous experienced specialists from outside the academic sphere. The IAEA (International Atomic Energy Agency) has added the Josef URC to its prestigious list of international training canters involved in the “Training in and Demonstration of Waste Disposal Technologies in Underground Research Facilities – A Network of Centers of Excellence” project

Cebama reference mix design for low-pH concrete and paste, preliminary characterisation

Trabajo presentado al Second Workshop of the HORIZON 2020 CEBAMA Project, celebrado en Espoo (Finlandia), del 16 al 18 de mayo de 2017.A reference low-pH concrete and paste mix were manufactured within the Cebama-project. Reference mixtures were casted at VTT in March 2016 and were distributed among some of the Cebama partners. Reference mix designs will be used by different partners as a common material to study their behaviour in contact with waters of different composition and interaction with radionuclides. Additionally, these materials will be used for model calibration. This article provides a summary of the characterization methods used by different partners and gives an overview of the experiments which will be made in the future with the reference materials.The research leading to these results has received funding from the European Union's Horizon 2020 Reasearch and Training Programme of the European Atomic Energy Community (EURATOM) (H2020-NFRP-2014/2015) under grant agreement n° 662147 (CEBAMA)