INMUNOGLOBULINA ANTI D

The long-term management of radioactive waste envisages the disposal of high-level radioactive waste (HLW) in low permeability media. High-level radioactive waste usually are stored first in a Centralised Temporary Storage (CTS) facility and later in a deep geological repository (DGR).

DGR is based on a multibarrier concept which combines natural barriers such as the geological formation and artificial barriers including the chemical forms of the waste, the metallic container, and the clay and concrete buffer and sealing materials. Reactive transport models are tools that help to understand and predict the time evolution of a DGR (De Windt et al., 2004, 2007; Samper et al., 2008a,b; Zheng et al., 2010, 2011; Kosakowski and Berner, 2013; Berner et al. 2013; Samper et al., 2016; Mon et al.,2017). In this dissertation, a non-isothermal multicomponent reactive transport model of the long- term interactions of compacted bentonite with the corrosion products of a carbon-steel canister and the concrete liner of the engineered barrier of a HLW repositories in clay has been carried out which takes into account the porosity changes due to mineral dissolution/precipitation and the feedback on flow, transport and chemical parameters. In addition, reactive transport models have been performed in this dissertation to simulate the non-linear transport and sorption of caesium through Opalinus clay which is considered a potential host rock for radioactive waste disposal.

Chapter 1. Introduction

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CTS is a storage system designed to host the spent fuel and high-level radioactive waste from nuclear power plants. The CTS facilities are the most ideal temporary solution from the security point of view since they allow the monitoring measures to be concentrated on a single facility and are the most convenient ones for leaving the way open for the eventual dismantling of the nuclear power plants themselves. These facilities have a concrete structure as a radiation shield and as security against unauthorised entries. Within the facility, the use of vaults or chambers enables the storage of a greater number of fuel assemblies at the lowest cost for both irradiated fuel and vitrified high-level radioactive waste. The results and experience accumulated by the international technical community are able to ensure the temporary storage of irradiated fuel for periods of 50 years or more. However, CTS facilities cannot be considered as a final permanent solution.

A large research effort has been devoted in the field of the radioactive waste repositories which in Spain has been promoted by ENRESA (Empresa Nacional de Residuos Radiactivos S.A.).

1.2.3.1. Centralised Temporary Storage (CTS) in Spain

On 30 December 2011, the Government of Spain designated the municipality of Villar de Cañas in Cuenca as the site of the Centralised Temporal Storage (CTS) and its Associated Technology Centre. (Figure 1.1). This facility will provide temporary storage for spent fuel and high-level radioactive waste from Spanish nuclear power plants. From the beginning of 2012, ENRESA has been working on the characterisation of the CTS site and the detailed design of the facility. In January 2014, applications for the prior (siting) authorisation and the construction permit were submitted to the Ministry of Industry, Energy and Tourism (MINETUR). These permits, granted by the MINETUR subsequent to approval by the Nuclear Safety Council (CSN), issued on 28 July 2015, and the Environmental Impact Statement from the Ministry of Agriculture, Food and the Environment (MAGRAMA), are required, along with the mandatory construction permit issued by Villar de Cañas Council, before the construction of the CTS site can begin. Once the construction of the CTS is complete, it will require an operating permit issued by the MINETUR, which must be accompanied by further authorisation from the autonomous communities and the EU (EURATOM).

The CTS has been designed for a 100-year life, although the current General Radioactive Waste Plan (GRWP) sets out an operational life of 60 years. After this time, the radioactive material will be removed for subsequent management and the facility will be dismantled, as with any other nuclear facility at the end of its operational life. The CTS will be a dry storage surface facility, ensuring the confinement of spent fuel from Spanish nuclear power plants and other high-level radioactive waste. According to the current GRWP, 12,000 m3 _{of nuclear materials will be stored at the CTS site. Most of}

them are spent fuel (about 20,000 fuel assemblies). There are only small quantities of vitrified waste (less than 70 canisters) and special waste.

Figure 1.1. Location of the municipality of Villar de Cañas where the construction of the CTS is planned and

3-D view of the future nuclear facilities (www.enresa.es).

Several numerical flow and reactive transport models have been performed by the University of A Coruña as part of the CTS site characterization activities. These numerical flow models which have been carried out during the course of this dissertation have been performed in several stages. Two flow models in vertical profiles in East-West direction at local and site scales were carried out in the first stage of the project in June 2014 (Samper et al., 2014a). In the second stage of the project (in December 2014), the two models performed in the previous stage were updated with additional measured data and an additional numerical model in a vertical profile in North-South direction at site scale was carried out (Samper et al., 2014b). The predictions of the effects of the construction of the nuclear facilities on the hydraulic heads were also performed with the numerical model in the second stage of the project. In the third stage of the project (in September 2016), the model in a vertical profile in East-West direction at local scale was updated and the following numerical models were carried out (Samper et al., 2016): 1) A 2-D horizontal flow model to simulate a long-term pumping test carried out in the creek located east of the nuclear zone of the CTS, 2) A 2-D horizontal flow model performed to analyse the potential impact of the Chaparral pumping well on the hydrogeological conditions in the nuclear zone of the CTS and 3) A 3-D flow model at local scale. In addition, heat transport, groundwater age, hydrogeochemical mixing and reactive transport models at the CTS site have been performed. Figure 1.2 shows the domain

Chapter 1. Introduction

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Figure 1.2. Geological map of the CTS showing the domains of the numerical models. The Záncara River, the

groundwater drainages defined in the 3-D model and the nuclear zone of the CTS site are also shown.