LONG-TERM SAFE STORAGE OF SPENT NUCLEAR FUEL FROM SHIP POWER UNITS IN UNDERGROUND STORAGE FACILITY IN THE NORTHWEST REGION OF RUSSIA

The definition of the thermal state of containers with spent nuclear fuel is important part of the ensuring of its safe storage during all period of storage facility operation. The this work all investigations are carried out for the storage containers of spent nuclear fuel of WWER-1000 reactors, which are operated in the Dry Spent Nuclear Fuel Storage Facility in Zaporizhska NPP. The analysis of existing investigations in the world nuclear engineering science concerning to the prediction of maximum temperatures in spent nuclear fuel storage container is carried out. The absence of studies in this field is detected and the necessity of the dependence for the maximum temperature in the storage container and temperature of cooling air on the exit of ventilation duct from variated temperatures of atmospheric air and decay heat formulation is pointed out. With usage of numerical simulation by solving of the conjugate heat transfer problems, the dependence of maximum temperatures in storage container with spent nuclear fuel from atmospheric temperature and decay heat is detected. The verification of used calculation method by comparison of measured air temperature on exit of ventilation channels and calculated temperature of cooling air was carried out. By regression analysis of numerical results of studies the dependence of ventilation air temperature from the temperature of atmospheric air and the decay heat of spent nuclear fuel was formulated. For the obtained dependence the statistical analysis was carried out and confidence interval with 95% of confidence is calculated. The obtained dependences are expediently to use under maximum temperature level estimation at specified operation conditions of spent nuclear fuel storage containers and for the control of correctness of thermal monitoring system work.

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Dissolution of spent nuclear fuel fragments at high alkaline conditions under H2 overpressure

MRS Advances ◽

10.1557/adv.2017.204 ◽

2016 ◽

Vol 1 (62) ◽

pp. 4163-4168

Author(s):

E. González-Robles ◽

M. Herm ◽

V. Montoya ◽

N. Müller ◽

B. Kienzler ◽

...

Keyword(s):

Aqueous Solution ◽

Partial Pressure ◽

Nuclear Fuel ◽

Alkaline Solution ◽

Spent Nuclear Fuel ◽

Dissolution Tests ◽

The Matrix ◽

Alkaline Conditions ◽

Long Term Behavior

ABSTRACTThe long-term behavior of the UO2 fuel matrix under conditions of the Belgian “Supercontainer design” was investigated by dissolution tests of high burn-up spent nuclear fuel (SNF) in high alkaline solution under 40 bar of (Ar + 8%H2) atmosphere. Four fragments of SNF, obtained from a pellet previously leached during two years, were exposed to young cement water with Ca (YCWCa) under 3.2 bar H2 partial pressure in four single/independent autoclave experiments for a period of 59, 182, 252 and 341 days, respectively. After a decrease of the concentration of dissolved 238U, which is associated with a reduction of U(VI) to U(IV), the concentration of 238U in solution is constant in the experiments running for 252 and 341 days. These observations indicate an inhibition of the matrix dissolution due to the presence of H2. A slight increase in the concentration of 90Sr and 137Cs in the aqueous solution indicates that there is still dissolution of the grain boundaries. These findings are similar to those reported for spent nuclear fuel corrosion in synthetic near neutral pH solutions.

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Using of optimization geometric design methods for the problems of the spent nuclear fuel safe storage

Artificial Intelligence ◽

10.15407/jai2020.03.051 ◽

2020 ◽

Vol 25 (3) ◽

pp. 51-63

Author(s):

Chugay A.M. ◽

◽

Alyokhina S.V. ◽

Keyword(s):

Mathematical Model ◽

Nonlinear Programming ◽

Nuclear Fuel ◽

Site Selection ◽

Spent Nuclear Fuel ◽

Optimal Placement ◽

Storage Site ◽

Safe Storage ◽

Geometric Objects ◽

Technological Limitations

Packing optimization problems have a wide spectrum of real-word applications. One of the applications of the problems is problem of placement of containers with spent nuclear fuel (SNF) on the storage platform. The solution of the problem can be reduced to the solution of the problem of finding the optimal placement of a given set of congruent circles into a multiconnected domain taking into account technological restrictions. A mathematical model of the prob-lem is constructed and its peculiarities are considered. Our approach is based on the mathematical modelling of rela-tions between geometric objects by means of phi-function technique. That allowed us to reduce the problem solving to nonlinear programming. Today, an important scientific problem is the problem of creating conditions for safe storage of spent nuclear fuel. In the process of creating any dry spent nuclear fuel storage, the following main stages can be identified: site selection, storage design, construction, operation and decommissioning. A full check for compliance of the repository and its elements with these standards usually begins at the design stage. At the stage of site selection, the inspection for compliance with safety standards is carried out only in terms of the impact of the repository as a whole on the environment. This approach cannot be considered fully appropriate, because, taking into account, for example, all the climatic features of the future storage site, it is possible to adjust the thermal storage regimes of spent nuclear fuel. Similarly, it can be considered necessary to analyze and select the shape of the storage site in order to accommo-date the maximum possible number of spent fuel containers. Such a choice, obviously, should be made taking into ac-count the norms of nuclear, radiation and thermal safety, as well as in compliance with technological limitations. The problem of finding the optimal placement of containers taking into account the given technological limitations can be formulated in the form of the problem of optimization of geometric design. Therefore, the purpose of the study is to build a mathematical model of the problem and study its characteristics to develop effective methods of solution. The proposed approach is based on mathematical modeling of relations between geometric objects using the method of phi-functions. This allowed to reduce the solution of the problem to the problem of nonlinear programming.

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Two-person game model of long-term safeguards for a final repository for spent nuclear fuel

Progress in Nuclear Energy ◽

10.1016/j.pnucene.2019.103058 ◽

2020 ◽

Vol 118 ◽

pp. 103058 ◽

Cited By ~ 1

Author(s):

Heejae Ju ◽

Il-Soon Hwang ◽

Sungyeol Choi

Keyword(s):

Nuclear Fuel ◽

Spent Nuclear Fuel ◽

Game Model ◽

Person Game

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Modeling of decay heat removal from CONSTOR RBMK-1500 casks during long-term storage of spent nuclear fuel

Energy ◽

10.1016/j.energy.2018.12.217 ◽

2019 ◽

Vol 170 ◽

pp. 978-985 ◽

Cited By ~ 3

Author(s):

R. Poškas ◽

V. Šimonis ◽

H. Jouhara ◽

P. Poškas

Keyword(s):

Nuclear Fuel ◽

Spent Nuclear Fuel ◽

Heat Removal ◽

Decay Heat ◽

Long Term Storage ◽

Term Storage

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Landscape Modeling for Dose Calculations in the Safety Assessment of a Repository for Spent Nuclear Fuel

11th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B ◽

10.1115/icem2007-7115 ◽

2007 ◽

Cited By ~ 1

Author(s):

Tobias Lindborg ◽

Ulrik Kautsky ◽

Lars Brydsten

Keyword(s):

Nuclear Fuel ◽

Safety Assessment ◽

Spent Nuclear Fuel ◽

Landscape Model ◽

Landscape Development ◽

Surface Hydrology ◽

Site Investigations ◽

Time Period ◽

The Individual

The Swedish Nuclear Fuel and Waste Management Co., (SKB), pursues site investigations for the final repository for spent nuclear fuel at two sites in the south eastern part of Sweden, the Forsmark- and the Laxemar site (figure 1). Data from the two site investigations are used to build site descriptive models of the areas. These models describe the bedrock and surface system properties important for designing the repository, the environmental impact assessment, and the long-term safety, i.e. up to 100,000 years, in a safety assessment. In this paper we discuss the methodology, and the interim results for, the landscape model, used in the safety assessment to populate the Forsmark site in the numerical dose models. The landscape model is built upon ecosystem types, e.g. a lake or a mire, (Biosphere Objects) that are connected in the landscape via surface hydrology. Each of the objects have a unique set of properties derived from the site description. The objects are identified by flow transport modeling, giving discharge points at the surface for all possible flow paths from the hypothetical repository in the bedrock. The landscape development is followed through time by using long-term processes e.g. shoreline displacement and sedimentation. The final landscape model consists of a number of maps for each chosen time period and a table of properties that describe the individual objects which constitutes the landscape. The results show a landscape that change over time during 20,000 years. The time period used in the model equals the present interglacial and can be used as an analogue for a future interglacial. Historically, the model area was covered by sea, and then gradually changes into a coastal area and, in the future, into a terrestrial inland landscape. Different ecosystem types are present during the landscape development, e.g. sea, lakes, agricultural areas, forest and wetlands (mire). The biosphere objects may switch from one ecosystem type to another during the modeled time period, from sea to lake, and from lake to mire and finally, some objects are transformed into agricultural area due to favorable farming characteristics.

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Developing a Concept for a National Used Fuel Interim Storage Facility in the United States

Volume 1: Low/Intermediate-Level Radioactive Waste Management; Spent Fuel, Fissile Material, Transuranic and High-Level Radioactive Waste Management ◽

10.1115/icem2013-96374 ◽

2013 ◽

Author(s):

Donald Wayne Lewis

Keyword(s):

United States ◽

Nuclear Fuel ◽

Nuclear Waste ◽

Spent Nuclear Fuel ◽

The United States ◽

Yucca Mountain ◽

Storage Facility ◽

Spent Fuel ◽

Geological Repository ◽

Interim Storage

In the United States (U.S.) the nuclear waste issue has plagued the nuclear industry for decades. Originally, spent fuel was to be reprocessed but with the threat of nuclear proliferation, spent fuel reprocessing has been eliminated, at least for now. In 1983, the Nuclear Waste Policy Act of 1982 [1] was established, authorizing development of one or more spent fuel and high-level nuclear waste geological repositories and a consolidated national storage facility, called a “Monitored Retrievable Storage” facility, that could store the spent nuclear fuel until it could be placed into the geological repository. Plans were under way to build a geological repository, Yucca Mountain, but with the decision by President Obama to terminate the development of Yucca Mountain, a consolidated national storage facility that can store spent fuel for an interim period until a new repository is established has become very important. Since reactor sites have not been able to wait for the government to come up with a storage or disposal location, spent fuel remains in wet or dry storage at each nuclear plant. The purpose of this paper is to present a concept developed to address the DOE’s goals stated above. This concept was developed over the past few months by collaboration between the DOE and industry experts that have experience in designing spent nuclear fuel facilities. The paper examines the current spent fuel storage conditions at shutdown reactor sites, operating reactor sites, and the type of storage systems (transportable versus non-transportable, welded or bolted). The concept lays out the basis for a pilot storage facility to house spent fuel from shutdown reactor sites and then how the pilot facility can be enlarged to a larger full scale consolidated interim storage facility.

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Methodological and Practical Bases of Providing Information Support to Activities on Environmental Remediation of the Spent Nuclear Fuel and Radioactive Waste Temporary Storage Facility in Gremikha

ASME 2011 14th International Conference on Environmental Remediation and Radioactive Waste Management, Parts A and B ◽

10.1115/icem2011-59375 ◽

2011 ◽

Author(s):

D. B. Stepennov ◽

A. P. Varnavin ◽

A. A. Zakharchev ◽

L. Pillette-Cousin

Keyword(s):

Radioactive Waste ◽

Nuclear Fuel ◽

Environmental Remediation ◽

Spent Nuclear Fuel ◽

Public Information ◽

Operating Experience ◽

Information Support ◽

Research Centre ◽

Storage Facility ◽

Temporary Storage

Remediation of a spent nuclear fuel (SNF) and radioactive waste (RW) temporary storage facility is a multifaceted process that includes a number of stages, such as development of a remediation programme, performance of comprehensive engineering and radiological survey, development of a remediation design, removal of SNF and RW up to the site cleanup. At any stage of the remediation, making of justified decisions is ensured by availability and completeness of associated information. Huge amount of information has to be managed. Therefore an information analysis system (IAS) was developed by the National Research Centre «Kurchatov Institute» within the framework of the project for environmental remediation of the SNF and RW temporary storage facility in Gremikha with financial and technical support provided by France (CEA) and the Russian Federation (Rosatom). The IAS accumulates all information about the project: technical and radiological characteristics of objects/facilities, cartographic information, documentation, data on the project participants, technologies and equipment involved. The IAS architecture includes the following functional subsystems: data management, data analytical processing, project management, geoinformation, 3D modeling, and public information. The IAS allows developers and performers of environmental remediation of the SNF and RW temporary storage facility in Gremikha to fulfill tasks arising at all stages of the work. The IAS operating experience can be transferred for use during surveys and remediation of any radiation hazardous facilities.

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