ACES addresses the EURATOM Work Programme 2019-2020, dedicated to Nuclear Fission and Radiation Protection Research (H2020 NFRP-2019-2020). Specifically, the proposal addresses the following work programme topic: A - Nuclear Safety - NFRP 1: Ageing phenomena of components and structures and operational issues. The main objective of ACES is to advance the assessment of safety performance of civil engineering structures by solving the remaining scientific and technological problems that currently hinder the safe and long-term operation of nuclear power plants reliant on safety-critical concrete infrastructure. Proper understanding of deterioration and ageing mechanisms requires a research strategy based on combined experimental and theoretical studies, following a multidisciplinary approach, and utilizing state of the art experimental and modelling techniques. Material characterization at different length scales (i.e., nano, micro, meso, and macro scales) is necessary, focusing on the physical understanding of the degradation processes (e.g., neutron and gamma radiation, internal swelling reactions, liner corrosion, etc.) as well as physical phenomena (drying, creep, shrinkage, etc.), and their influence on macroscopic mechanical properties and structural/ functional integrity of the components. The ACES project aims at having a significant impact on the safety of operational Gen II and III NPPs and impacting the design of next-generation plants. ACES will improve the understanding of ageing/ deterioration of concrete and will demonstrate and quantify inherent safety margins introduced by the conservative approaches used during design and defined by codes and standards employed through-out the life of the plant. The outcomes from ACES will therefore support the LTO of NPPs. This will be achieved by using more advanced and realistic scientific methods to assess the integrity of NPP concrete infrastructure. The project will provide evidence to support the methods by carrying out various tests, including large scale tests based on replicated scenarios of NPPs. ACES engages 11 partners from five EU Member States (BE, CZ, FI, FR, SI) and two non-EU countries (UA and USA).

Naloga obsega raziskave korozije bakra v talni vodi in bentonitu podzemnega odlagališča izrabljenega jedrskega goriva v bodočem odlagališču Äspö na Švedskem. V bakrenih zabojnikih s 5 cm debelo steno, ki bodo obdani z bentonitom, bo v rovih v granitnem masivu 500 m globoko pod zemljo, odloženo izrabljeno jedrsko gorivo. V nalogi sodelujemo z KTH - Royal Institute of Technology Stockholm in naročnikom SKB (Svensk Kämbränsllehantering AB - Swedish Nuclear Fuel and Waste Management Co).

V okviru raziskovalnega projekta MICROSENS, ki ga je sponzorirala Evropska komisija smo v sodelovanju z Inštitutom za kemijo/analizno kemijo (prof. dr. Kurt Klacher) na Univerzi Karla Franza v Gradcu, Avstrija, razvijali in preučevali elektrokemijske senzorje za določevanje kloridov v porni vodi betona. Razvili smo merilni sistem, ki omogoča kontinuirno zasledovanje penetracije kloridnih ionov v porozno betonsko matriko.

Poročilo vsebuje rezultate laboratorijskih raziskav efektivnosti novih inhibitorjev, ki naj bi bili aplicirani na površino betona. Ugotovili smo, da je pasivacija jekla možna le, če je vsebnost inhibitorja višja od vsebnosti kloridov v betonu (ostali parametri so manj pomembni). V kolikor ta pogoj ni zagotovljen, so možne izrazite lokalne oblike korozije. Dokazali smo, da tudi že po doseženi pasivaciji ob znižanju koncentracije inhibitorja (simulacija izpiranja iz betona) lahko pride do ponovne iniciacije korozijski procesov. Pokazali smo, da delovanje organskih inhibitorjev lahko relevantno ocenimo le s kombinacijo različnih elektrokemijskih metod.

Test Parcel of copper and bentonite was exposed for six years in the Äspo HardRock Laboratory, which offers a realistic environment for the conditions that will prevail in a deep repository for high-level radioactive waste disposal in Sweden. In January 2007 electric resistance (ER) sensors of pure copper were also installed in test package from deep repository. The results from the ER measurements of corrosion rate of copper from start in January 2007 to April 2011 are presented in this report. In summary, the measurements have shown that the corrosion rate of pure copper exposed to an oxic bentonite/saline groundwater environment can be followed by ER and electrochemical techniques, and corrosion rate decreases slowly with time to very low values (