Long-term safety of the extended SFR - Methodology and conclusions from the SR-PSU project

MRS Advances ◽  
2016 ◽  
Vol 1 (61) ◽  
pp. 4075-4080
Author(s):  
Fredrik Vahlund
Keyword(s):  
Radioactive Waste ◽  
Nuclear Fuel ◽  
Nuclear Power ◽  
Safety Assessment ◽  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Surface System ◽  
Radiological Safety ◽  
The Impact

ABSTRACTSince 1988 the Swedish Nuclear Fuel and Waste Management Co. operates a repository for low- and intermediate-level short-lived radioactive waste, SFR, in Forsmark, Sweden. Due to decommissioning of the nuclear power plants additional storage capacity is needed. In December 2014, an application to extend the repository was therefore submitted. One key component of this application was an assessment of post-closure safety of the extended SFR. For this safety assessment, a methodology based on that developed by SKB for the spent nuclear fuel repository was used and the impact of the degradation of repository components, the evolution of the surface system and changes of future climate on the radiological safety of the repository was assessed over a period of 100,000 years. The central conclusion of the SR-PSU safety assessment is that the extended SFR repository meets requirements on protection of human health and of the environment that have been established by the Swedish radiation safety authority for the final disposal of radioactive waste. Furthermore, the design of the repository was shown suitable for the waste selected and the applied methodology suitable for the safety assessment.

scholarly journals Approaches to Safety Justification for Loading of VSC-VVER Containers in ZNPP DSFSF

2019 ◽  
pp. 82-87
Author(s):  
Ya. Kostiushko ◽  
O. Dudka ◽  
Yu. Kovbasenko ◽  
A. Shepitchak
Keyword(s):  
Nuclear Fuel ◽  
Nuclear Power ◽  
Safety Assessment ◽  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Operating Conditions ◽  
Spent Fuel ◽  
Fuel Assemblies ◽  
Fuel Storage ◽  
The Government

The introduction of new fuel for nuclear power plants in Ukraine is related to obtaining a relevant license from the regulatory authority for nuclear and radiation safety of Ukraine. The same approach is used for spent nuclear fuel (SNF) management system. The dry spent fuel storage facility (DSFSF) is the first nuclear facility created for intermediate dry storage of SNF in Ukraine. According to the design based on dry ventilated container storage technology by Sierra Nuclear Corporation and Duke Engineering and Services, ventilated storage containers (VSC-VVER) filled with SNF of VVER-1000 are used, which are located on a special open concrete site. Containers VSC-VVER are modernized VSC-24 containers customized for hexagonal VVER-1000 spent fuel assemblies. The storage safety assessment methodology was created and improved directly during the licensing process. In addition, in accordance with the Energy Strategy of Ukraine up to 2035, one of the key task is the further diversification of nuclear fuel suppliers. Within the framework of the Executive Agreement between the Government of Ukraine and the U.S. Government, activities have been underway since 2000 on the introduction of Westinghouse fuel. The purpose of this project is to develop, supply and qualify alternative nuclear fuel compatible with fuel produced in Russia for Ukrainian NPPs. In addition, a supplementary approach to safety analysis report is being developed to justify feasibility of loading new fuel into the DSFSF containers. The stated results should demonstrate the fulfillment of design criteria under normal operating conditions, abnormal conditions and design-basis accidents of DSFSF components.  Thus, the paper highlights both the main problems of DSFSF licensing and obtaining permission for placing new fuel types in DSFSF.

Simulation and Analysis: The Dose Distribution of KBS-3 Spent Nuclear Fuel Canister by MCNP

2010 ◽  
Author(s):  
Bo Yang ◽  
He-xi Wu ◽  
Yi-bao Liu
Keyword(s):  
Cast Iron ◽  
Radioactive Waste ◽  
Nuclear Fuel ◽  
Nuclear Power ◽  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Ductile Cast Iron ◽  
Nuclear Industry ◽  
Spent Fuel ◽  
High Level

With the sustained and rapid development of the nuclear power plants, the spent fuel which is produced by the nuclear power plants will be rapidly rising. Spent fuel is High-level radioactive waste and should be disposed safely, which is important for the environment of land, public safety and health of the nuclear industry, the major issues of sustainable development and it is also necessary part for the nuclear industry activities. It is important to study and resolve the high-level radioactive waste repository problem. Spent nuclear fuel is an important component in the radioactive waste, The KBS-3 canister for geological disposal of spent nuclear fuel in Sweden consists of a ductile cast iron insert and a copper shielding. The ductile cast iron insert provides the mechanical strength whereas the copper protects the canister from corrosion. The canister inserts material were referred to as I24, I25 and I26, Spent nuclear fuel make the repository in high radiant intensity. The radiation analysis of canister insert is important in canister transport, the dose analysis of repository and groundwater radiolysis. Groundwater radiolysis, which produces oxidants (H2O2 and O2), will break the deep repository for spent nuclear fuel. The dose distribution of canister surface with different kinds of canister inserts (I24, I25 and I26) is calculated by MCNP (Ref. 1). Analysing the calculation results, we offer a reference for selecting canister inserts material.

scholarly journals Radiation Effects on Materials Used in Geological Repositories for Spent Nuclear Fuel

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Mats Jonsson
Keyword(s):  
Ionizing Radiation ◽  
Nuclear Fuel ◽  
Nuclear Power ◽  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Safety Analysis ◽  
Nuclear Industry ◽  
Barrier Materials ◽  
Materials Used

Safe long-term storage of radioactive waste from nuclear power plants is one of the main concerns for the nuclear industry as well as for governments in countries relying on electricity produced by nuclear power. A repository for spent nuclear fuel must be safe for extremely long time periods (at least 100 000 years). In order to ascertain the long-term safety of a repository, extensive safety analysis must be performed. One of the critical issues in a safety analysis is the long-term integrity of the barrier materials used in the repository. Ionizing radiation from the spent nuclear constitutes one of the many parameters that need to be accounted for. In this paper, the effects of ionizing radiation on the integrity of different materials used in a granitic deep geological repository for spent nuclear fuel designed according to the Swedish KBS-3 model are discussed. The discussion is primarily focused on radiation-induced processes at the interface between groundwater and solid materials. The materials that are discussed are the spent nuclear fuel (based on UO2), the copper-covered iron canister, and bentonite clay. The latter two constitute the engineered barriers of the repository.

scholarly journals Prevention of Damage to Spent Nuclear Fuel during Handling Operations

2020 ◽  
pp. 62-71
Author(s):  
M. Sapon ◽  
O. Gorbachenko ◽  
S. Kondratyev ◽  
V. Krytskyy ◽  
V. Mayatsky ◽  
...  
Keyword(s):  
Nuclear Fuel ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Nuclear Fuel ◽  
Spent Fuel ◽  
Long Term Storage ◽  
Fuel Storage ◽  
Storage Facilities

According to regulatory requirements, when carrying out handling operations with spent nuclear fuel (SNF), prevention of damage to the spent fuel assemblies (SFA) and especially fuel elements shall be ensured. For this purpose, it is necessary to exclude the risk of SFA falling, SFA uncontrolled displacements, prevent mechanical influences on SFA, at which their damage is possible. Special requirements for handling equipment (in particular, cranes) to exclude these dangerous events, the requirements for equipment strength, resistance to external impacts, reliability, equipment design solutions, manufacturing quality are analyzed in this work. The requirements of Ukrainian and U.S. regulatory documents also are considered. The implementation of these requirements is considered on the example of handling equipment, in particular, spent nuclear fuel storage facilities. This issue is important in view of creation of new SNF storage facilities in Ukraine. These facilities include the storage facility (SFSF) for SNF from water moderated power reactors (WWER): a Сentralized SFSF for storing SNF of Rivne, Khmelnitsky and South-Ukraine Nuclear Power Plants (СSFSF), and SFSF for SNF from high-power channel reactors (RBMK): a dry type SFSF at Chornobyl nuclear power plant (ISF-2). After commissioning of these storage facilities, all spent nuclear fuel from Ukrainian nuclear power plants will be placed for long-term “dry” storage. The safety of handling operations with SNF during its preparation for long-term storage is an important factor.

Safety Aspects in Dry Storage of Spent Nuclear Fuel in Long Term Operation for Brazilian Nuclear Power Plants

2020 ◽  
Vol 18 (10) ◽  
pp. 1807-1816
Author(s):  
Claudir Jose Nodari ◽  
Pedro Luiz da Cruz Saladanha ◽  
Gladson Silva Fontes
Keyword(s):  
Nuclear Fuel ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Nuclear Fuel ◽  
Term Operation ◽  
Dry Storage ◽  
Safety Aspects

The impact of Ignalina Nuclear Power Plant on Carbon-14 content in Lake Druksiai, Lithuania

2020 ◽  
Author(s):  
Laurynas Butkus ◽  
Rūta Barisevičiūtė ◽  
Žilvinas Ežerinskis ◽  
Justina Šapolaitė ◽  
Evaldas Maceika ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Fuel ◽  
Sediment Core ◽  
Nuclear Power ◽  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Carbon 14 ◽  
Fish Samples ◽  
The Impact

<p>Nuclear Power Plants (NPPs) and nuclear fuel reprocessing sites are main producers of anthropogenic radiocarbon. Anthropogenic <sup>14</sup>C can be released into the environment in gaseous forms, with liquid effluents or with spent nuclear fuel [1]. During photosynthesis radiocarbon can be easily assimilated into the plants. As a result, carbon-14 can be transported through the food chain and accumulate in a human body. Therefore, radiocarbon is considered a primary source of increased human radiation dose from industrial nuclear activities [2].</p><p>Main goal of this research was to evaluate the influence Ignalina NPP on carbon-14 content in the Lake Druksiai. The sediment core was collected from the Lake Druksiai. The ages of sediment layers were estimated using <sup>137</sup>Cs and <sup>210</sup>Pb dating methods. ABA (acid-base-acid) chemical pretreatment procedure was used to extract humin (HM) and humic acid (HA) fractions from the sediments. Chemically pretreated samples were graphitized with the Automated Graphitization Equipment AGE 3 (IonPlus AG). Carbon-14 measurements in prepared samples were performed using the single stage accelerator mass spectrometer (SSAMS, NEC, USA).</p><p>Radiocarbon content was measured in the sediment core which covers all phases of the NPP exploitation (commissioning, operation and decommissioning). These measurements in HM and HA fractions showed that after the start of the operation of the Ignalina NPP in 1983, the <sup>14</sup>C concentration in these organic fractions increased by 4 pMC and 3 pMC, respectively. In addition, a sharp increase of radiocarbon content (concentration almost doubled) in HA fraction was observed in the year 1999. Similar increase in <sup>14</sup>C activity in fish samples from Lake Druksiai was measured. In HM fraction such drastic changes in radiocarbon concentration were not observed. These results suggest that <sup>14</sup>C enriched effluents were released from the Ignalina NPP in 1999.</p><p>[1] Z. Ezerinskis et al., Annual Variations of 14C Concentration in the Tree Rings in the Vicinity of Ignalina Nuclear Power Plant, Radiocarbon 60, 1227–1236 (2018).</p><p>[2] IAEA, Generic Models for Use in Assessing the Impact of Discharges of Radioactive Substances to the Environment (2001).</p>

scholarly journals Twenty years of research on spent nuclear fuel in the context of final disposal at KIT-INE in multinational collaborative projects

2021 ◽  
Vol 1 ◽  
pp. 237-238
Author(s):  
Michel Herm ◽  
Elke Bohnert ◽  
Luis Iglesias Pérez ◽  
Tobias König ◽  
Volker Metz ◽  
...  
Keyword(s):  
Nuclear Fuel ◽  
Nuclear Power ◽  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Iron Corrosion ◽  
Reducing Conditions ◽  
Deep Geological Disposal ◽  
Preferential Option ◽  
Radionuclide Release

Abstract. Disposal of spent nuclear fuel (SNF) in deep geological repositories is considered a preferential option for the management of such wastes in many countries with nuclear power plants. With the aim to permanently and safely isolate the radionuclide inventory from the biosphere for a sufficient time, a multibarrier system consisting of technical, geotechnical and geological barriers is interposed between the emplaced waste and the environment. In safety assessments for deep underground repositories, access of water, followed by failure of canisters and finally loss of the cladding integrity is considered in the long-term. Hence, evaluating the performance of SNF in deep geological disposal systems requires process understanding of SNF dissolution and rates as well as quantification of radionuclides release from SNF under reducing conditions of a breached container. In order to derive a radionuclide source term, the SNF dissolution and alteration processes can be assigned to two steps: (i) instantaneous release of radionuclides upon cladding failure from gap and grain boundaries and (ii) a long-term release that results from dissolution of the fuel grains itself (Ewing, 2015). In this context, research at KIT-INE has focused for more than 20 years on the behavior of SNF (irradiated UO2 and MOX fuels) under geochemical conditions (pH, redox and ionic strength) representative of various repository concepts, including the interaction of SNF with backfill material, such as bentonite as well as the influence of iron corrosion products, e.g. magnetite and radiolytic reactions on SNF dissolution mechanisms. Since 2001, KIT-INE has contributed with experimental and theoretical studies on the behavior of SNF under repository relevant conditions to six Euratom projects viz SFS (2001–2004), NF-PRO (2004–2006), MICADO (2006–2009), RECOSY (2007–2011), FIRST-Nuclides (2012–2014) and DISCO (2016–2021). Moreover, since 2007, overall 4 consecutive projects for the Belgian waste management organization, ONDRAF-NIRAS, were performed on the behavior of SNF under conditions representative of the Belgian “Supercontainer” concept. In this contribution, we summarize major achievements of theses research projects to understand and quantify the radionuclide release from dissolving SNF under repository conditions. In particular, the dependence of radionuclide release on the chemical composition of the aqueous and gaseous phase in the proximity of repositories in different types of host rock is discussed.

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