Application of Spent Fuel Characterization and Leaching Studies for Validating Alteration Models

2007 ◽  
Author(s):  
Javier Quin˜ones ◽  
Joaquin Cobos Sabate ◽  
Eduardo Iglesias ◽  
Nieves Rodriguez ◽  
Aurora Marti´nez-Esparza
Keyword(s):  
Performance Assessment ◽  
Corrosion Behaviour ◽  
Point Of View ◽  
Spent Fuel ◽  
Long Period ◽  
Geological Repository ◽  
Key Issues ◽  
Fuel Characterization ◽  
Or Modelling

From the Spanish point of view, one of the key issues related to the HLW performance assessment is knowing and predicting, or modelling, the behaviour of spent fuel under geological repository conditions. Taking into account this objective, several experiments have been performed in order to split and determine the influence of different variables on the final stability of the spent fuel matrix in the geological repository. This paper presents some of the leaching results obtained with spent fuel and chemical analogues (UO2, alpha doped – UO2, SIMFUEL,) their application to extrapolate the corrosion behaviour for a long period of time and compare with corresponding data obtained using models. This procedure allows pointing out some of the uncertainties whose minimization is necessary to improve the models useful for performance assessment studies.

Performance assessment of the geosphere barrier of a deep geological repository for spent fuel

1997 ◽  
Vol 176 (1-2) ◽  
pp. 155-162 ◽  
Author(s):  
Kristina Skagius ◽  
Marie Wiborgh ◽  
Anders Ström ◽  
Lena Morén
Keyword(s):  
Performance Assessment ◽  
Deep Geological Repository ◽  
Spent Fuel ◽  
Geological Repository

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

Studies and Research on the Corrosion Behavior of Ni-Al2O3 Compound Coatings Obtained by Electrochemical Methods

2020 ◽  
Vol 43 (3) ◽  
pp. 21-25
Author(s):  
Simona BOICIUC ◽  
◽  
◽  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Corrosion Behaviour ◽  
Composite Coatings ◽  
Point Of View ◽  
Electrochemical Methods ◽  
Dispersed Phase ◽  
Nickel Matrix ◽  
Technical Alumina ◽  
Compound Coatings

The undertaken research which is described in this paper aims at the corrosion behaviour of composite coatings in nickel matrix using as dispersed phase technical alumina with dimensions of 5 μm and their characterization from a microstructural point of view. The corrosion resistance in the saline fog of the coatings is influenced by the microstructure, the stresses developed in the layer and the roughness.

Remembering From-the-Outside

2018 ◽  
Author(s):  
Christopher McCarroll
Keyword(s):  
Empirical Evidence ◽  
Point Of View ◽  
Philosophical Analysis ◽  
Visual Perspective ◽  
Observer Perspective ◽  
The Status ◽  
Key Issues ◽  
Way Of Thinking

This chapter sets out some key issues related to a philosophical analysis of point of view in memory. It does so by looking at examples of psychological, philosophical, and literary accounts of the phenomenon, as well as examples of the author’s own observer perspective memories. The chapter provides an overview of some of the empirical evidence related to visual perspective in memory. Despite these consistent empirical findings, however, a number of doubts and misconceptions about remembering from-the-outside still linger, especially concerning the status of observer perspectives in memory. This chapter outlines some of the skepticism to the possibility of remembering from-the-outside and points to a possible diagnosis of why such skepticism arises. This chapter points to a way of thinking about memory—to be developed through the course of the book—which eases the worries about remembering from-the-outside.

The holistic risk analysis of spent fuel pool considering the fuel route risk

2021 ◽  
pp. 1748006X2199851
Author(s):  
Zhixin Xu ◽  
Ming Wang ◽  
Binyan Song ◽  
WenYu Hou ◽  
Chao Wang
Keyword(s):  
Nuclear Power ◽  
Comprehensive Evaluation ◽  
Point Of View ◽  
Spent Fuel ◽  
Nuclear Disaster ◽  
Evaluation Approach ◽  
Fuel Assemblies ◽  
Spent Fuel Pool ◽  
Large Water ◽  
Fukushima Nuclear Disaster

The Fukushima nuclear disaster has raised the importance on the reliability and risk research of the spent fuel pool (SFP), including the risk of internal events, fire, external hazards and so on. From a safety point of view, the low decay heat of the spent fuel assemblies and large water inventory in the SFP has made the accident progress goes very slow, but a large number of fuel assemblies are stored inside the spent fuel pool and without containment above the SFP building, it still has an unignored risk to the safety of the nuclear power plant. In this paper, a standardized approach for performing a holistic and comprehensive evaluation approach of the SFP risk based on the probabilistic safety analysis (PSA) method has been developed, including the Level 1 SFP PSA and Level 2 SFP PSA and external hazard PSA. The research scope of SFP PSA covers internal events, internal flooding, internal fires, external hazards and new risk source-fuel route risk is also included. The research will provide the risk insight of Spent Fuel Pool operation, and can help to make recommendation for the prevention and mitigation of SFP accidents which will be applicable for the SFP configuration risk management.

History: changing the forms or forming the changes?

2005 ◽  
Vol 13 (1) ◽  
pp. 47-66 ◽  
Author(s):  
SVEND ERIK LARSEN
Keyword(s):  
Cultural History ◽  
18Th Century ◽  
Point Of View ◽  
Future Planning ◽  
Long Period ◽  
Close Analysis ◽  
Vitruvian Man ◽  
Human Responsibility ◽  
The Individual ◽  
Individual Human

Change in European cultural history has, for a long period, been discussed through two interrelated notions, that of science and that of history. This paper traces the various stages of this discussion from Antiquity to the present day from the point of view of history. Two reoccurring and paradigmatic characters of mythological descent, Odysseus and Prometheus, illustrate how history as a realm for human responsibility and future planning has established itself as a specific European construct, with the 18th century as its final breakthrough in practical and ideological terms. A close analysis of Leonardo da Vinci's drawing the Vitruvian Man, in statu nascendi, shows how the individual human being carrying the obligations and the promises of this history, is envisioned. The final remarks underline the importance of scientific knowledge in the concrete shaping of this responsibility and a plea for an increased cooperation across the disciplines.

The Effect of Bromide on Oxygen Yields in Homogeneous α-radiolysis

MRS Advances ◽  
2017 ◽  
Vol 2 (13) ◽  
pp. 711-716 ◽  
Author(s):  
Lovisa Bauhn ◽  
Christian Ekberg ◽  
Patrik Fors ◽  
Kastriot Spahiu
Keyword(s):  
Radiation Field ◽  
Spent Nuclear Fuel ◽  
Radiation Doses ◽  
Deep Geological Repository ◽  
Spent Fuel ◽  
Mass Spectrometric Measurement ◽  
Α Decay ◽  
Geological Repository ◽  
Dissolved Ions ◽  
Dissolved Hydrogen

ABSTRACTIn a scenario where ground water enters a canister for spent nuclear fuel in a deep geological repository, the presence of dissolved ions in the water could possibly influence the fuel dissolution due to effects on radiolysis yields. One species of particular interest in this context is bromide, which has a proven ability to scavenge hydroxyl radicals much faster than molecular hydrogen does. As a result, bromide could inhibit the beneficial effect of dissolved hydrogen, which has been shown in γ-radiolysis experiments. However, already a few hundred years after repository closure, α-decay starts to dominate in the radiation field from the spent fuel. Hence, the effects of α-radiolysis are expected to govern the fuel dissolution over the geological timeframes of the repository. In the present work, α-radiolysis experiments have been performed to determine the effect of bromide ions on the yield of hydrogen peroxide by mass spectrometric measurement of its decomposition product oxygen. The use of high activity 238Pu solutions has made it possible to study this effect during pure α-radiolysis from a homogeneously distributed radiation field. To simulate deep bedrock repository conditions, and to minimize the influence of in-leaking O2 from air, the studies were performed using graphite sealed stainless steel autoclaves with an initial atmosphere of 10 bar H2. The results show that addition of 1 mM Br- to the solution gives no significant effect on the O2 yield for radiation doses up to 2 MGy. This lack of effect is most likely explained by the limited radical escape yields from radiation tracks in pure α-radiolysis.

scholarly journals Strengthening the SSTC NRS Scientific and Technical Potential through Participation in the IAEA Coordinated Research Projects

2021 ◽  
pp. 5-13
Author(s):  
Yu. Balashevska ◽  
D. Gumenyuk ◽  
Iu. Ovdiienko ◽  
O. Pecherytsia ◽  
I. Shevchenko ◽  
...  
Keyword(s):  
Best Practices ◽  
Safety Assessment ◽  
Radiation Safety ◽  
Research Projects ◽  
Spent Fuel ◽  
Research Activities ◽  
Technical Potential ◽  
Technical Issues ◽  
Fuel Characterization ◽  
Definition Of

The State Scientific and Technical Center for Nuclear and Radiation Safety (SSTC NRS), a Ukrainian enterprise with a 29-year experience in the area of scientific and technical support to the national nuclear regulator (SNRIU), has been actively involved in international research activities. Participation in the IAEA coordinated research activities is among the SSTC NRS priorities. In the period of 2018–2020, the IAEA accepted four SSTC NRS proposals for participation in respective Coordinated Research Projects (CRPs). These CRPs address scientific and technical issues in different areas such as: 1) performance of probabilistic safety assessment for multi-unit/multi-reactor sites; 2) use of dose projection tools to ensure preparedness and response to nuclear and radiological emergencies; 3) phenomena related to in-vessel melt retention; 4) spent fuel characterization. This article presents a brief overview of the abovementioned projects with definition of scientific contributions by the SSTC NRS (participation in benchmarks, development of methodological documents on implementing research stages and of IAEA technical documents (TECDOC) for demonstration of best practices and results of research carried out by international teams).

scholarly journals Optimal Stopping and Utility in a Simple Modelof Unemployment Insurance

Risks ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 94
Author(s):  
Jason S. Anquandah ◽  
Leonid V. Bogachev
Keyword(s):  
Simple Model ◽  
Unemployment Insurance ◽  
Optimal Stopping ◽  
Point Of View ◽  
Call Option ◽  
Optimal Stopping Problem ◽  
Optimal Decisions ◽  
Key Issues ◽  
The Unemployed ◽  
New Jobs

Managing unemployment is one of the key issues in social policies. Unemployment insurance schemes are designed to cushion the financial and morale blow of loss of job but also to encourage the unemployed to seek new jobs more proactively due to the continuous reduction of benefit payments. In the present paper, a simple model of unemployment insurance is proposed with a focus on optimality of the individual’s entry to the scheme. The corresponding optimal stopping problem is solved, and its similarity and differences with the perpetual American call option are discussed. Beyond a purely financial point of view, we argue that in the actuarial context the optimal decisions should take into account other possible preferences through a suitable utility function. Some examples in this direction are worked out.

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