Climate and climate-related issues for the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Naeslund, Jens-Ove (comp.)

2006-11-15

The purpose of this report is to document current scientific knowledge of the climate-related conditions and processes relevant to the long-term safety of a KBS-3 repository to a level required for an adequate treatment in the safety assessment SR-Can. The report also includes a concise background description of the climate system. The report includes three main chapters: A description of the climate system (Chapter 2); Identification and discussion of climate-related issues (Chapter 3); and, A description of the evolution of climate-related conditions for the safety assessment (Chapter 4). Chapter 2 includes an overview of present knowledge of the Earth climate system and the climate conditions that can be expected to occur in Sweden on a 100,000 year time perspective. Based on this, climate-related issues relevant for the long-term safety of a KBS-3 repository are identified. These are documented in Chapter 3 'Climate-related issues' to a level required for an adequate treatment in the safety assessment. Finally, in Chapter 4, 'Evolution of climate-related conditions for the safety assessment' an evolution for a 120,000 year period is presented, including discussions of identified climate-related issues of importance for repository safety. The documentation is from a scientific point of view not exhaustive, since such a treatment is neither necessary for the purposes of the safety assessment nor possible within the scope of a safety assessment. As further described in the SR-Can Main Report and in the Features Events and Processes report, the content of the present report has been audited by comparison with FEP databases compiled in other assessment projects. This report follows as far as possible the template for documentation of processes regarded as internal to the repository system. However, the term processes is not used in this report, instead the term issue has been used. Each issue includes a set of processes together resulting in the

Handling of future human actions in the safety assessment SR-Can

International Nuclear Information System (INIS)

Moren, Lena

2006-10-01

This report documents the future human actions (FHA) considered in the long-term safety analysis of a KBS-3 repository. The report is one of the supporting documents to the safety assessment SR-Can. The purpose of this report is to provide an account of: General considerations concerning FHA; The methodology applied in SR-Can to assess FHA; The aspects of FHA that need to be considered in the evaluation of their impact on a deep geological repository; and The selection of representative scenarios for illustrative consequence analysis

Handling of future human actions in the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Moren, Lena

2006-10-15

This report documents the future human actions (FHA) considered in the long-term safety analysis of a KBS-3 repository. The report is one of the supporting documents to the safety assessment SR-Can. The purpose of this report is to provide an account of: General considerations concerning FHA; The methodology applied in SR-Can to assess FHA; The aspects of FHA that need to be considered in the evaluation of their impact on a deep geological repository; and The selection of representative scenarios for illustrative consequence analysis.

Fuel and canister process report for the safety assessment SR-Can

International Nuclear Information System (INIS)

Werme, Lars

2006-10-01

This report documents fuel and canister processes identified as relevant to the long-term safety of a KBS-3 repository. It forms an important part of the reporting of the safety assessment SR-Can. The detailed assessment methodology, including the role of the process report in the assessment, is described in the SR-Can Main report. The report is written by, and for, experts in the relevant scientific fields. It should though be possible for a generalist in the area of long-term safety assessments of geologic nuclear waste repositories to comprehend the contents of the report. The report is an important part of the documentation of the SR-Can project and an essential reference within the project, providing a scientifically motivated plan for the handling of geosphere processes. It is, furthermore, foreseen that the report will be essential for reviewers scrutinising the handling of geosphere issues in the SR-Can assessment. Several types of fuel will be emplaced in the repository. For the reference case with 40 years of reactor operation, the fuel quantity from boiling water reactors, BWR fuel, is estimated at 7,000 tonnes, while the quantity from pressurized water reactors, PWR fuel, is estimated at about 2,300 tonnes. In addition, 23 tonnes of mixed-oxide fuel (MOX) fuel of German origin from BWR and PWR reactors and 20 tonnes of fuel from the decommissioned heavy water reactor in Aagesta will be disposed of. To allow for future changes in the Swedish nuclear programme, the safety assessment assumes a total of 6,000 canister corresponding to 12,000 tonnes of fuel

Fuel and canister process report for the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Werme, Lars (ed.)

2006-10-15

This report documents fuel and canister processes identified as relevant to the long-term safety of a KBS-3 repository. It forms an important part of the reporting of the safety assessment SR-Can. The detailed assessment methodology, including the role of the process report in the assessment, is described in the SR-Can Main report. The report is written by, and for, experts in the relevant scientific fields. It should though be possible for a generalist in the area of long-term safety assessments of geologic nuclear waste repositories to comprehend the contents of the report. The report is an important part of the documentation of the SR-Can project and an essential reference within the project, providing a scientifically motivated plan for the handling of geosphere processes. It is, furthermore, foreseen that the report will be essential for reviewers scrutinising the handling of geosphere issues in the SR-Can assessment. Several types of fuel will be emplaced in the repository. For the reference case with 40 years of reactor operation, the fuel quantity from boiling water reactors, BWR fuel, is estimated at 7,000 tonnes, while the quantity from pressurized water reactors, PWR fuel, is estimated at about 2,300 tonnes. In addition, 23 tonnes of mixed-oxide fuel (MOX) fuel of German origin from BWR and PWR reactors and 20 tonnes of fuel from the decommissioned heavy water reactor in Aagesta will be disposed of. To allow for future changes in the Swedish nuclear programme, the safety assessment assumes a total of 6,000 canister corresponding to 12,000 tonnes of fuel.

Audit of data and code use in the SR-Can safety assessment

Energy Technology Data Exchange (ETDEWEB)

Hicks, T.W.; Baldwin, T.D. [Galson Sciences Ltd, 5 Grosvenor House, Melton R oad, Oakham, Rutland LE15 6AX (United Kingdom)

2008-03-15

Building on the findings of previous studies on data and code quality assurance (QA) in safety assessments, this report provides a review of data and code QA in the SR-Can safety assessment. The data quality audit aimed to check that the selection and use of data in the SR-Can safety assessment was appropriate, focusing on the data that underpin representations of and assumptions about canister, insert, buffer, and backfill behaviour. The SR-Can Data Report provided the initial focus for examining the traceability and reliability of data used in the safety assessment; the Data Report is one of the series of SR-Can safety assessment reports and, in this review, it was anticipated that it would provide the primary source of data on the canister, insert, buffer, and backfill. However, other safety assessment reports (the SR-Can Main Report, the Initial State Report, the Fuel and Canister Process Report, and the Buffer and Backfill Process Report) were found to provide key information on data used in the safety assessment. The quality audit of codes aimed to check that code use in the SR-Can safety assessment has been justified through a transparent and traceable process of code development and selection. The Model Summary Report provided the focus for reviewing the QA status of the codes used in the safety assessment. As well as highlighting a number of concerns regarding QA aspects of specific data sets, parameter values, and codes used in the SR-Can safety assessment (which are presented in the report), the review has led to several general observations on data and code QA that should be considered by SKB in the development and implementation of a QA system for the SR-Site safety assessment: - The SR-Site safety assessment and associated QA records should include information that demonstrates that a full QA system has been implemented in order to build confidence in the validity of the assessment. - The data and parameter values used directly in the safety

Planning report for the safety assessment SR-Can

International Nuclear Information System (INIS)

2003-06-01

This document is a planning report for SKB's next assessment of long-term safety for a KBS 3 repository. The assessment, SR-Can, is to be finished by the end of 2005 and will be used for SKB's application to build an Encapsulation plant for spent nuclear fuel. Apart from outlining the methodology, the report discusses the handling in SR-Can of a number of important issues regarding the near field, the geosphere, the biosphere, the climatic evolution etc. The Swedish nuclear safety and radiation protection authorities have recently issued regulations concerning the final disposal of nuclear waste. The principal compliance criterion states that the annual risk of harmful effects must not exceed 10 -6 for a representative individual in the group exposed to the greatest risk. There are also a number of requirements on methodological aspects of the safety assessment as well as on the contents of a safety report. The regulations are reproduced in an Appendix to this report. The primary safety function of the KBS 3 system is to completely isolate the spent nuclear fuel within copper canisters over the entire assessment period, which will be one million years in SR-Can. Should a canister be damaged, the secondary safety function is to retard any releases from the canisters. The main steps of the assessment are the following: 1. Qualitative system description, FEP processing: This step consists of defining a system boundary and of describing the system on a format suitable for the safety assessment. Databases of relevant features, events and processes influencing long-term safety are structured and used as one starting point for the assessment. 2. Initial state descriptions. 3. Process descriptions: In this step all identified processes within the system boundary involved in the long-term evolution of the system are described in detail. 4. Description of boundary conditions: This step is a broad description of the evolution of the boundaries of the system, focussing mainly

Model summary report for the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Vahlund, Fredrik

2006-10-15

This document is the model summary report for the safety assessment SR-Can. In the report, the quality assurance measures conducted for the assessment codes are presented together with the chosen methodology. In the safety assessment SR-Can, a number of different computer codes are used. In order to better understand how these codes are related Assessment Model Flowcharts, AMFs, have been produced within the project. From these, it is possible to identify the different modelling tasks and consequently also the different computer codes used. A large number of different computer codes are used in the assessment of which some are commercial while others are developed especially for the current assessment project. QA requirements must on the one hand take this diversity into account and on the other hand be well defined. In the methodology section of the report the following requirements are defined: It must be demonstrated that the code is suitable for its purpose; It must be demonstrated that the code has been properly used; and, It must be demonstrated that the code development process has followed appropriate procedures and that the code produces accurate results. Although the requirements are identical for all codes, the measures used to show that the requirements are fulfilled will be different for different codes (for instance due to the fact that for some software the source-code is not available for review). Subsequent to the methodology section, each assessment code is presented and it is shown how the requirements are met.

Model summary report for the safety assessment SR-Can

International Nuclear Information System (INIS)

Vahlund, Fredrik

2006-10-01

This document is the model summary report for the safety assessment SR-Can. In the report, the quality assurance measures conducted for the assessment codes are presented together with the chosen methodology. In the safety assessment SR-Can, a number of different computer codes are used. In order to better understand how these codes are related Assessment Model Flowcharts, AMFs, have been produced within the project. From these, it is possible to identify the different modelling tasks and consequently also the different computer codes used. A large number of different computer codes are used in the assessment of which some are commercial while others are developed especially for the current assessment project. QA requirements must on the one hand take this diversity into account and on the other hand be well defined. In the methodology section of the report the following requirements are defined: It must be demonstrated that the code is suitable for its purpose; It must be demonstrated that the code has been properly used; and, It must be demonstrated that the code development process has followed appropriate procedures and that the code produces accurate results. Although the requirements are identical for all codes, the measures used to show that the requirements are fulfilled will be different for different codes (for instance due to the fact that for some software the source-code is not available for review). Subsequent to the methodology section, each assessment code is presented and it is shown how the requirements are met

Planning report for the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-06-01

This document is a planning report for SKB's next assessment of long-term safety for a KBS 3 repository. The assessment, SR-Can, is to be finished by the end of 2005 and will be used for SKB's application to build an Encapsulation plant for spent nuclear fuel. Apart from outlining the methodology, the report discusses the handling in SR-Can of a number of important issues regarding the near field, the geosphere, the biosphere, the climatic evolution etc. The Swedish nuclear safety and radiation protection authorities have recently issued regulations concerning the final disposal of nuclear waste. The principal compliance criterion states that the annual risk of harmful effects must not exceed 10{sup -6} for a representative individual in the group exposed to the greatest risk. There are also a number of requirements on methodological aspects of the safety assessment as well as on the contents of a safety report. The regulations are reproduced in an Appendix to this report. The primary safety function of the KBS 3 system is to completely isolate the spent nuclear fuel within copper canisters over the entire assessment period, which will be one million years in SR-Can. Should a canister be damaged, the secondary safety function is to retard any releases from the canisters. The main steps of the assessment are the following: 1. Qualitative system description, FEP processing: This step consists of defining a system boundary and of describing the system on a format suitable for the safety assessment. Databases of relevant features, events and processes influencing long-term safety are structured and used as one starting point for the assessment. 2. Initial state descriptions. 3. Process descriptions: In this step all identified processes within the system boundary involved in the long-term evolution of the system are described in detail. 4. Description of boundary conditions: This step is a broad description of the evolution of the boundaries of the system

An Assessment of SKB's Performance Assessment Calculations in the Interim Main Report for the Safety Assessment SR-Can

International Nuclear Information System (INIS)

Maul, Philip; Robinson, Peter

2005-03-01

SKB have published their Interim Main Report of the safety assessment SR-Can, which is intended to establish the framework for what will be submitted in 2006 in support of a licence application for construction of the spent fuel encapsulation plant. This follows on from the SR-Can Planning Document published in 2003. The purpose of the Interim Report is stated to be to demonstrate the methodology that will be used for safety assessment. The present report evaluates the information provided in the Interim SR-Can Report that is relevant to the Performance Assessment (PA) calculations that SKB intend to undertake, using independent calculations to facilitate this process. SKB consider that the primary safety function is to isolate completely the fuel within the canisters over the entire assessment period. Should a canister be damaged, the secondary safety function is to ensure that any release is retarded and dispersed sufficiently to ensure that concentrations levels in the accessible environment cannot cause unacceptable consequences. In this report PA calculations are considered to include both a high-level representation of the evolution of the system (relevant to the primary safety function), and any subsequent radionuclide transport (relevant to the secondary safety function). The main conclusions drawn are: 1. The effects of climate evolution on engineered barriers have not been analysed in detail in the Interim Report, and this limits the usefulness of the preliminary calculations that have been undertaken. 2. A key aspect of SKB's approach is the use of an integrated near-field evolution model. The information provided on this model demonstrates its capability efficiently to reproduce calculations from individual process models, but insufficient information is given at the present time to justify statements about interactions between processes. In particular it is assumed that relatively short term thermal and resaturation processes do not affect the

SSI's independent consequence calculations in support of the regulatory review of the SR-Can safety assessment

International Nuclear Information System (INIS)

Shulan Xu; Dverstorp, Bjoern; Woerman, Anders; Marklund, Lars; Klos, Richard; Shaw, George

2008-03-01

With the publication of the SR-Can report at the end of 2006, Swedish Nuclear Fuel and Waste Management Co (SKB) have presented a complete assessment of long-term safety for a KBS-3 repository. The SR-Can project demonstrates progress in SKB's capabilities in respect of the methodology for assessment of long-term safety in support of a licence application for a final repository. According to SKB's plans, applications to construct a geological repository will be submitted in 2009, supported by post-closure safety assessments. Project CLIMB (Catchment LInked Models of radiological effects in the Biosphere) was instituted in 2004 to provide SSI with an independent modelling capability when reviewing SKB's assessments. Modelling in CLIMB covers all aspects of performance assessment (PA) from nearfield releases to radiological consequences in the surface environment. This review of SR-Can provides the first opportunity to apply the models and to compare the CLIMB approach with developments at SKB. The aim of the independent calculations is to investigate key aspects of the PA models and so to better understand the assessment methodology used by SKB. Independent modelling allows critical review issues to be addressed by the application of alternative models and assumptions. Three reviews are undertaken here: - Reproduction of selected cases from SR-Can in order to demonstrate an adequate understanding of the PA model from details given in the SR-Can documentation. - Alternative conceptualisation of radionuclide transport and accumulation in the surface system. Two modelling approaches have been used: GEMA (the Generic Ecosystem Modelling Approach) is a traditional compartmental model similar to that used by SKB in SR-Can but with additional functionality and flexibility. The second approach takes continuous transport models to investigate contaminant migration through the Quaternary deposits into the surface drainage system. - The final strand of the CLIMB investigation

FEP report for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

2010-12-15

This report documents the analysis and processing of features, events and processes, FEPs, that has been carried out within the safety assessment SR-Site, and forms an important part of the reporting of the project. The main part of the work was conducted within the earlier safety assessment SR-Can, which was a preparatory stage for the SR-Site assessment. The overall objective of the FEP analysis and processing in both SR-Can and SR-Site included development of a database of features, events and processes, an SKB FEP database, in a format that facilitates both a systematic analysis of FEPs and documentation of that FEP analysis, as well as facilitating revisions and updates to be made in connection with new safety assessments. The primary objective in SR-Site was to establish an SR-Site FEP catalogue within the framework of the SKB FEP database. This FEP catalogue was required to contain all FEPs that needed to be handled in SR-Site and is an update of the corresponding SR-Can FEP catalogue that was established for the SR-Can assessment. The starting point for the handling of FEPs in SR-Site was the SR-Can version of the SKB FEP database and associated SR-Can reports. The SR-Can version of the SKB FEP database includes the SR-Can FEP catalogue, as well as the sources for the identification of FEPs in SR-Can, namely the SR 97 processes and variables, Project FEPs in the NEA International FEP database version 1.2 and matrix interactions in the Interaction matrices developed for a deep repository of the KBS-3 type. Since the completion of the FEP work within SR-Can, an updated electronic version, version 2.1, of the NEA FEP database has become available. Compared with version 1.2 of the NEA FEP database, version 2.1 contains FEPs from two more projects. As part of SR-Site, all new Project FEPs in version 2.1 of the NEA FEP database have been mapped according to the methodology adopted in SR-Can resulting in an SR-Site version of the SKB FEP database. The SKB FEP

FEP report for the safety assessment SR-Site

International Nuclear Information System (INIS)

2010-12-01

This report documents the analysis and processing of features, events and processes, FEPs, that has been carried out within the safety assessment SR-Site, and forms an important part of the reporting of the project. The main part of the work was conducted within the earlier safety assessment SR-Can, which was a preparatory stage for the SR-Site assessment. The overall objective of the FEP analysis and processing in both SR-Can and SR-Site included development of a database of features, events and processes, an SKB FEP database, in a format that facilitates both a systematic analysis of FEPs and documentation of that FEP analysis, as well as facilitating revisions and updates to be made in connection with new safety assessments. The primary objective in SR-Site was to establish an SR-Site FEP catalogue within the framework of the SKB FEP database. This FEP catalogue was required to contain all FEPs that needed to be handled in SR-Site and is an update of the corresponding SR-Can FEP catalogue that was established for the SR-Can assessment. The starting point for the handling of FEPs in SR-Site was the SR-Can version of the SKB FEP database and associated SR-Can reports. The SR-Can version of the SKB FEP database includes the SR-Can FEP catalogue, as well as the sources for the identification of FEPs in SR-Can, namely the SR 97 processes and variables, Project FEPs in the NEA International FEP database version 1.2 and matrix interactions in the Interaction matrices developed for a deep repository of the KBS-3 type. Since the completion of the FEP work within SR-Can, an updated electronic version, version 2.1, of the NEA FEP database has become available. Compared with version 1.2 of the NEA FEP database, version 2.1 contains FEPs from two more projects. As part of SR-Site, all new Project FEPs in version 2.1 of the NEA FEP database have been mapped according to the methodology adopted in SR-Can resulting in an SR-Site version of the SKB FEP database. The SKB FEP

SSI's independent consequence calculations in support of the regulatory review of the SR-Can safety assessment

Energy Technology Data Exchange (ETDEWEB)

Shulan Xu; Dverstorp, Bjoern (Swedish Radiation Protection Authority, Stockholm (Sweden)); Woerman, Anders; Marklund, Lars (Royal Institute of Technology (KTH), Stockholm (SE)); Klos, Richard (Aleksandria Sciences, Sheffield (GB)); Shaw, George (Univ. of Nottingham (GB))

2008-03-15

With the publication of the SR-Can report at the end of 2006, Swedish Nuclear Fuel and Waste Management Co (SKB) have presented a complete assessment of long-term safety for a KBS-3 repository. The SR-Can project demonstrates progress in SKB's capabilities in respect of the methodology for assessment of long-term safety in support of a licence application for a final repository. According to SKB's plans, applications to construct a geological repository will be submitted in 2009, supported by post-closure safety assessments. Project CLIMB (Catchment LInked Models of radiological effects in the Biosphere) was instituted in 2004 to provide SSI with an independent modelling capability when reviewing SKB's assessments. Modelling in CLIMB covers all aspects of performance assessment (PA) from nearfield releases to radiological consequences in the surface environment. This review of SR-Can provides the first opportunity to apply the models and to compare the CLIMB approach with developments at SKB. The aim of the independent calculations is to investigate key aspects of the PA models and so to better understand the assessment methodology used by SKB. Independent modelling allows critical review issues to be addressed by the application of alternative models and assumptions. Three reviews are undertaken here: - Reproduction of selected cases from SR-Can in order to demonstrate an adequate understanding of the PA model from details given in the SR-Can documentation. - Alternative conceptualisation of radionuclide transport and accumulation in the surface system. Two modelling approaches have been used: GEMA (the Generic Ecosystem Modelling Approach) is a traditional compartmental model similar to that used by SKB in SR-Can but with additional functionality and flexibility. The second approach takes continuous transport models to investigate contaminant migration through the Quaternary deposits into the surface drainage system. - The final strand of the CLIMB

Review of SR-Can: Evaluation of SKB's handling of spent fuel performance, radionuclide chemistry and geosphere transport parameters. External review contribution in support of SKI's and SSI's review of SR-Can

International Nuclear Information System (INIS)

Stenhouse, Mike; Jegou, Christophe; Brown, Paul; Meinrath, Guenther; Nitsche, Heino; Ekberg, Christian

2008-03-01

SR-Can covers the containment phase of the KBS-3 barriers as well as the consequences of releases of radionuclides to the rock and eventually the biosphere (after complete containment within fuel canisters has partially failed). The aim of this report is to provide a range of review comments with respect to those parameters related to spent fuel performance as well as radionuclide chemistry and transport. These parameter values are used in the quantification of consequences due to release of radionuclides from potentially leaking canisters. The report does not cover modelling approaches used for quantification of consequences. However, modelling used to derive parameter values is to some extent addressed (such as calculation of maximum radionuclide concentration due to formation of solubility limiting phases). The following are the key highlights and comments generated in the course of the review: Inconsistencies exist between recommendations provided in technical reports and those quoted in the Data Report. One of the reasons for such inconsistencies has been the timing of different pieces of research. It is hoped that the timing of contributions to SR-Site will be such that these inconsistencies can be avoided. Sensitivity analyses need to be carried out and reported in a number of areas to support some of the assumptions or decisions made in the assessment calculations. The likelihood is that SKB has performed many of the sensitivity analyses identified in different parts of this report, but these need to be reported, preferably to complement the recommendations provided

Review of SR 97 performance assessment

International Nuclear Information System (INIS)

Glynn, P.D.

2000-01-01

This review has identified many technical problems in the SR 97 performance assessment. The general impression of this reviewer is that SKB has been disingenuous in its performance assessment effort. It has not cited important differences of opinion with its own views. Furthermore, there are many inconsistencies in the SR 97 report that all together leave the impression that there are many more uncertainties in the SR 97 performance assessment than SKB would perhaps care to admit. Additionally, despite SKB's statements to the contrary, many of the analyses conducted for the SR 97 performance assessment can be clearly shown not to have been based on 'conservative' assumptions. Finally, SKB has made little effort to consider possible coupling effects between their different scenarios in SR 97. This is a serious flaw in the SR 97 performance assessment. The comments in this review should not be taken to imply that the KBS-3 nuclear waste disposal method will not be able to meet the safety and radiation protection requirements which SKI and SSI have specified in recent years. Instead, my conclusion is simply that the SR 97 performance assessment of the KBS-3 method would have been more believable had it been based on a forthright and comprehensive discussion of facts, uncertainties and opinions, and on a more conservative choice of assumptions. As it stands, the SR 97 performance assessment is not very credible

Buffer and backfill process report for the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Sellin, Patrik (comp.)

2006-09-15

This document compiles information on processes in the buffer and deposition tunnel backfill relevant for long-term safety of a KBS-repository. It supports the safety assessment SR-Can, which is a preparatory step for a safety assessment that will support the licence application for a final repository in Sweden. The purpose of the process reports is to document the scientific knowledge of the processes to a level required for an adequate treatment of the processes in the safety assessment. The documentation is not exhaustive from a scientific point of view, since such a treatment is neither necessary for the purposes of the safety assessment nor possible within the scope of an assessment. However, it must be sufficiently detailed to motivate, by arguments founded on scientific understanding, the treatment of each process in the safety assessment. The purpose is further to determine how to handle each process in the safety assessment at an appropriate degree of detail, and to demonstrate how uncertainties are taken care of, given the suggested handling.

Buffer and backfill process report for the safety assessment SR-Can

International Nuclear Information System (INIS)

Sellin, Patrik

2006-09-01

This document compiles information on processes in the buffer and deposition tunnel backfill relevant for long-term safety of a KBS-repository. It supports the safety assessment SR-Can, which is a preparatory step for a safety assessment that will support the licence application for a final repository in Sweden. The purpose of the process reports is to document the scientific knowledge of the processes to a level required for an adequate treatment of the processes in the safety assessment. The documentation is not exhaustive from a scientific point of view, since such a treatment is neither necessary for the purposes of the safety assessment nor possible within the scope of an assessment. However, it must be sufficiently detailed to motivate, by arguments founded on scientific understanding, the treatment of each process in the safety assessment. The purpose is further to determine how to handle each process in the safety assessment at an appropriate degree of detail, and to demonstrate how uncertainties are taken care of, given the suggested handling

SR-can: preliminary feedback to canister fabrication, repository design and future R and D

International Nuclear Information System (INIS)

Hedin, A.; Sellin, P.

2007-01-01

This paper discusses preliminary feedback from SKB's on-going safety assessment SR-Can, to he finalized in 2006. The assessment, which is not part of a formal licence application, is an important step towards the SR-Site assessment to be delivered in 2008 and which will support a licence application for a Swedish deep repository for spent nuclear fuel. The SR-Can assessment will use data from the initial stage of the on-going site investigations at the two candidate sites at Forsmark and Oskarshamn. Review comments on SR-Can from Swedish authorities are expected in the summer of 2007 and these will be taken into account when preparing the SR-Site assessment. An Interim version of the SR-Can report was produced in September 2004 and has been reviewed by the Swedish authorities supported by an international review team. The assessment concerns a KBS 3 repository for which the key safety related features can be summarised in the primary safety function isolation and the secondary function retardation. The isolation function is more prominent in the KBS 3 method compared to many other repository concepts. (authors)

SKI's and SSI's review of SKB's safety report SR-Can

International Nuclear Information System (INIS)

Dverstorp, Bjoern; Stroemberg, Bo

2008-03-01

This report summarises SKI's and SSI's joint review of the Swedish Nuclear Fuel and Waste Management Co's (SKB) safety report SR-Can (SKB TR-06-09). SR-Can is the first assessment of post-closure safety for a KBS-3 spent nuclear fuel repository at the candidate sites Forsmark and Laxemar, respectively. The analysis builds on data from the initial stage of SKB's surface-based site investigations and on data from full-scale manufacturing and testing of buffer and copper canisters. SR-Can can be regarded as a preliminary version of the safety report that will be required in connection with SKB's planned licence application for a final repository in late 2009. The main purpose of the authorities' review is to provide feedback to SKB on their safety reporting as part of the pre-licensing consultation process. However, SR-Can is not part of the formal licensing process. In support of the authorities' review three international peer review teams were set up to make independent reviews of SR-Can from three perspectives, namely integration of site data, representation of the engineered barriers and safety assessment methodology, respectively. Further, several external experts and consultants have been engaged to review detailed technical and scientific issues in SR-Can. The municipalities of Oesthammar and Oskarshamn where SKB is conducting site investigations, as well NGOs involved in SKB's programme, have been invited to provide their views on SR-Can as input to the authorities' review. Finally, the authorities themselves, and with the help of consultants, have used independent models to reproduce part of SKB's calculations and to make complementary calculations. All supporting review documents are published in SKI's and SSI's report series. The main findings of the review are: -SKB's safety assessment methodology is overall in accordance with applicable regulations, but part of the methodology needs to be further developed for the licence application. -SKB's quality

Interim initial state report for the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Pers, Karin (ed.) [Kemakta Konsult AB, Stockholm (Sweden)

2004-07-01

A thorough description of the initial state of the engineered parts of the repository system is one of the main bases for the SR-Can safety assessment. The initial state refers to the state at the time of deposition for the spent fuel and the engineered barriers and the natural, undisturbed state at the time of beginning of excavation for the repository for the geosphere and the biosphere. The repository system is based on the KBS-3 method, where copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at approximately 500 m depth in saturated, granitic rock. For the purpose of the safety assessment the engineered portion of the repository system has been divided into a number of consecutive barriers or sub-systems. The importance of a particular feature for safety has influenced the resolution into components. In principle, components close to the source term and those that play an important role for safety are treated in more detail than more peripheral components. For the option with 40 years of reactor operation, the quantity of BWR fuel is estimated at 7200 tonnes and the quantity of PWR fuel at 2300 tonnes. The fuel burn-up may vary from 15 MWd/kgU up to 60 MWd/kg. Geometric aspects of the fuel cladding tubes of importance in the safety assessment are, as a rule, handled sufficiently pessimistically in analyses of radionuclide transport that differences between different fuel types are irrelevant. The relative differences in radionuclide inventory with respect to burn-up are small. Deviations in inventory and deviating or damaged fuel are not considered in the SR-Can interim reporting but will be handled in the final reporting of SR-Can. The canister consists of an inner container, the insert of cast iron and an outer shell of copper. The cast iron insert provides mechanical stability and the copper shell protects against corrosion in the repository environment. The copper shell is 5 cm thick and

Interim initial state report for the safety assessment SR-Can

International Nuclear Information System (INIS)

Pers, Karin

2004-07-01

A thorough description of the initial state of the engineered parts of the repository system is one of the main bases for the SR-Can safety assessment. The initial state refers to the state at the time of deposition for the spent fuel and the engineered barriers and the natural, undisturbed state at the time of beginning of excavation for the repository for the geosphere and the biosphere. The repository system is based on the KBS-3 method, where copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at approximately 500 m depth in saturated, granitic rock. For the purpose of the safety assessment the engineered portion of the repository system has been divided into a number of consecutive barriers or sub-systems. The importance of a particular feature for safety has influenced the resolution into components. In principle, components close to the source term and those that play an important role for safety are treated in more detail than more peripheral components. For the option with 40 years of reactor operation, the quantity of BWR fuel is estimated at 7200 tonnes and the quantity of PWR fuel at 2300 tonnes. The fuel burn-up may vary from 15 MWd/kgU up to 60 MWd/kg. Geometric aspects of the fuel cladding tubes of importance in the safety assessment are, as a rule, handled sufficiently pessimistically in analyses of radionuclide transport that differences between different fuel types are irrelevant. The relative differences in radionuclide inventory with respect to burn-up are small. Deviations in inventory and deviating or damaged fuel are not considered in the SR-Can interim reporting but will be handled in the final reporting of SR-Can. The canister consists of an inner container, the insert of cast iron and an outer shell of copper. The cast iron insert provides mechanical stability and the copper shell protects against corrosion in the repository environment. The copper shell is 5 cm thick and

Review of SR-Can: Evaluation of SKB's handling of spent fuel performance, radionuclide chemistry and geosphere transport parameters. External review contribution in support of SKI's and SSI's review of SR-Can

Energy Technology Data Exchange (ETDEWEB)

Stenhouse, Mike (Monitor Scientific LLC, Denver, CO (US)); Jegou, Christophe (Commissariat a l' Energie Atomique (CEA) (FR)); Brown, Paul (Geochem Australia (AU)); Meinrath, Guenther (RER Consultants, Passau (DE)); Nitsche, Heino (Univ. of California, Berkeley (US)); Ekberg, Christian (Chalmers University of Technology (SE))

2008-03-15

SR-Can covers the containment phase of the KBS-3 barriers as well as the consequences of releases of radionuclides to the rock and eventually the biosphere (after complete containment within fuel canisters has partially failed). The aim of this report is to provide a range of review comments with respect to those parameters related to spent fuel performance as well as radionuclide chemistry and transport. These parameter values are used in the quantification of consequences due to release of radionuclides from potentially leaking canisters. The report does not cover modelling approaches used for quantification of consequences. However, modelling used to derive parameter values is to some extent addressed (such as calculation of maximum radionuclide concentration due to formation of solubility limiting phases). The following are the key highlights and comments generated in the course of the review: Inconsistencies exist between recommendations provided in technical reports and those quoted in the Data Report. One of the reasons for such inconsistencies has been the timing of different pieces of research. It is hoped that the timing of contributions to SR-Site will be such that these inconsistencies can be avoided. Sensitivity analyses need to be carried out and reported in a number of areas to support some of the assumptions or decisions made in the assessment calculations. The likelihood is that SKB has performed many of the sensitivity analyses identified in different parts of this report, but these need to be reported, preferably to complement the recommendations provided

Determination and assessment of the concentration limits to be used in SR-Can. Supplement to TR-06-32

International Nuclear Information System (INIS)

Grive, Mireia; Domenech, Cristina; Montoya, Vanessa; Garcia, David; Duro, Lara

2010-09-01

This document complements and updates the report TR-06-32, Determination and assessment of the concentration limits to be used in SR-Can, in which the solubility limits of different radionuclides in the near field system and under the different scenarios selected by SKB were assessed. Since 2006, several important changes in different fields affecting solubility assessment calculations have been reported. These changes basically concern some of the thermodynamic data used in the calculations and the groundwater compositions for scenarios of interest defined by SKB. In this document we update the thermodynamic data corresponding to Ni, Zr, Th and U and we describe the thermodynamic database selected for Pb. This document also reports the update of the assessment of the concentration limits to be used in SR-Can, which has been done considering the recent thermodynamic database updates and the new groundwater compositions of interest supplied by SKB. Finally, we also present the Simple Functions spreadsheet tool, born from the need of having a confident and easy-to-handle tool to calculate solubility limits of some radionuclides under determined conditions in an agile and relatively fast manner

Determination and assessment of the concentration limits to be used in SR-Can. Supplement to TR-06-32

Energy Technology Data Exchange (ETDEWEB)

Grive, Mireia; Domenech, Cristina; Montoya, Vanessa; Garcia, David; Duro, Lara

2010-09-15

This document complements and updates the report TR-06-32, Determination and assessment of the concentration limits to be used in SR-Can, in which the solubility limits of different radionuclides in the near field system and under the different scenarios selected by SKB were assessed. Since 2006, several important changes in different fields affecting solubility assessment calculations have been reported. These changes basically concern some of the thermodynamic data used in the calculations and the groundwater compositions for scenarios of interest defined by SKB. In this document we update the thermodynamic data corresponding to Ni, Zr, Th and U and we describe the thermodynamic database selected for Pb. This document also reports the update of the assessment of the concentration limits to be used in SR-Can, which has been done considering the recent thermodynamic database updates and the new groundwater compositions of interest supplied by SKB. Finally, we also present the Simple Functions spreadsheet tool, born from the need of having a confident and easy-to-handle tool to calculate solubility limits of some radionuclides under determined conditions in an agile and relatively fast manner

Tracing sediment sources in upstream agricultural catchments: contribution of elemental geochemistry, 87Sr/86Sr ratio and radionuclides measurements

International Nuclear Information System (INIS)

Le-Gall, Marion

2016-01-01

Soil erosion is recognized as one of the main processes of land degradation in agricultural environments. This study develops an original fingerprinting method to examine sediment source contributions in two contrasted agricultural catchments. Several properties were used to trace sediment lithological sources ( 87 Sr/ 86 Sr ratios, elemental concentrations), soil surface and subsurface sources ( 137 Cs) and to quantify their temporal dynamics ( 7 Be, 210 Pb xs ). In the Louroux catchment (24 km 2 , France), representative of drained areas of Northwestern Europe, results showed the dominant contribution of very fine particles (≤2 μm) transiting through the tile drainage system to suspended sediment. Sediment accumulated in the river channel was mainly exported during the two first floods investigated in 2013 whereas the next event was characterized by the transport of sediment eroded from the cultivated soil surface. Mixing models were used, and results indicated that surface sources contributed the majority of sediment deposited in the pond, at the outlet of the catchment. The two lithological sources, discriminated using 87 Sr/ 86 Sr ratios, contributed in similar proportions to downstream pond sediment. In contrast, significant variations were observed since the 1950's. These changes may be related to the progressive implementation of land consolidation schemes within the catchment. Results obtained in the Louroux catchment revealed the potential of 87 Sr/ 86 Sr ratios to trace sediment lithological sources. The methodology was then applied to the larger and steeper Guapore catchment (2000 km 2 , Brazil), exposed to a more erosive climate and characterized by contrasted laterite soils. 87 Sr/ 86 Sr ratios and elements that discriminated the five soil types found in the catchment were incorporated in mixing models. Results showed that the major part of sediment was supplied by soils located in lower catchment parts. This result suggests the higher

Determination and assessment of the concentration limits to be used in SR-Can

Energy Technology Data Exchange (ETDEWEB)

Duro, L; Grive, M; Cera, E; Gaona, X; Domenech, C; Bruno, J [Enviros Spain S.L., Barcelona (Spain)

2006-12-15

This report presents the results for solubility limit calculations for the SR-Can assessment. It has been organized into five chapters that constitute the core of the report, supported by several appendices containing additional and supporting information. The updated thermodynamic database used to conduct the solubility calculations has been issued as a separate report. The near field system for which the concentration limits of the radionuclides are assessed and the scenarios selected by SKB to calculate the solubility limits are thoroughly described. Several sources of information have been used to support the calculated solubility limits. In particular results from selected spent fuel dissolution experiments and natural analogue data are discussed to introduce the proper perspective to the results from the thermodynamic calculations. In addition, the main conceptual and numerical uncertainties associated to the assessment of the concentration limits of each element are numerically evaluated and discussed. Equilibrium calculations have been conducted to select the solubility limiting solid phase for each element. Furthermore a sensitivity analysis of parameters of interest for each element is presented and the impact of the uncertainties identified on the solubility of each element quantified. The results are presented in a series of tables containing the calculated solubility for each radionuclide under the reference conditions. Finally concentration limits that are recommended result from the expert judgement built-up around the various sources of information together with the quantification of radionuclide solubility data and their associated uncertainties. The results are compared to previous solubility limits determination performed by SKB in SR 97, as well as the recommended values from other HLNW management organisations.

Determination and assessment of the concentration limits to be used in SR-Can

International Nuclear Information System (INIS)

Duro, L.; Grive, M.; Cera, E.; Gaona, X.; Domenech, C.; Bruno, J.

2006-12-01

This report presents the results for solubility limit calculations for the SR-Can assessment. It has been organized into five chapters that constitute the core of the report, supported by several appendices containing additional and supporting information. The updated thermodynamic database used to conduct the solubility calculations has been issued as a separate report. The near field system for which the concentration limits of the radionuclides are assessed and the scenarios selected by SKB to calculate the solubility limits are thoroughly described. Several sources of information have been used to support the calculated solubility limits. In particular results from selected spent fuel dissolution experiments and natural analogue data are discussed to introduce the proper perspective to the results from the thermodynamic calculations. In addition, the main conceptual and numerical uncertainties associated to the assessment of the concentration limits of each element are numerically evaluated and discussed. Equilibrium calculations have been conducted to select the solubility limiting solid phase for each element. Furthermore a sensitivity analysis of parameters of interest for each element is presented and the impact of the uncertainties identified on the solubility of each element quantified. The results are presented in a series of tables containing the calculated solubility for each radionuclide under the reference conditions. Finally concentration limits that are recommended result from the expert judgement built-up around the various sources of information together with the quantification of radionuclide solubility data and their associated uncertainties. The results are compared to previous solubility limits determination performed by SKB in SR 97, as well as the recommended values from other HLNW management organisations

Design premises for a KBS-3V repository based on results from the safety assessment SR-Can and some subsequent analyses

Energy Technology Data Exchange (ETDEWEB)

2009-11-15

The objective with this report is to: - provide design premises from a long term safety aspect of a KBS-3V repository for spent nuclear fuel, to form the basis for the development of the reference design of the repository. The design premises are used as input to the documents, called production reports, that present the reference design to be analysed in the long term safety assessment SR-Site. It is the aim that the production reports should verify that the chosen design complies with the design premises given in this report, whereas this report takes the burden of justifying why these design premises are relevant. The more specific aims and objectives with the production reports are provided in these reports. The following approach is used: - The reference design analysed in SR-Can is a starting point for setting safety related design premises for the next design step. - A few design basis cases, in accordance with the definition used in the regulation SSMFS 2008:211 and mainly related to the canister, can be derived from the results of the SR-Can assessment. From these it is possible to formulate some specific design premises for the canister. - The design basis cases involve several assumptions on the state of other barriers. These implied conditions are thus set as design premises for these barriers. - Even if there are few load cases on individual barriers that can be directly derived from the analyses, SR-Can provides substantial feedback on most aspects of the analysed reference design. This feedback is also formulated as design premises. - An important part of SR-Can Main report is the formulation and assessment of safety function indicator criteria. These criteria are a basis for formulating design premises, but they are not the same as the design premises discussed in the present report. Whereas the former should be upheld throughout the assessment period, the latter refer to the initial state and must be defined such that they give a margin for

Design premises for a KBS-3V repository based on results from the safety assessment SR-Can and some subsequent analyses

International Nuclear Information System (INIS)

2009-11-01

The objective with this report is to: - provide design premises from a long term safety aspect of a KBS-3V repository for spent nuclear fuel, to form the basis for the development of the reference design of the repository. The design premises are used as input to the documents, called production reports, that present the reference design to be analysed in the long term safety assessment SR-Site. It is the aim that the production reports should verify that the chosen design complies with the design premises given in this report, whereas this report takes the burden of justifying why these design premises are relevant. The more specific aims and objectives with the production reports are provided in these reports. The following approach is used: - The reference design analysed in SR-Can is a starting point for setting safety related design premises for the next design step. - A few design basis cases, in accordance with the definition used in the regulation SSMFS 2008:211 and mainly related to the canister, can be derived from the results of the SR-Can assessment. From these it is possible to formulate some specific design premises for the canister. - The design basis cases involve several assumptions on the state of other barriers. These implied conditions are thus set as design premises for these barriers. - Even if there are few load cases on individual barriers that can be directly derived from the analyses, SR-Can provides substantial feedback on most aspects of the analysed reference design. This feedback is also formulated as design premises. - An important part of SR-Can Main report is the formulation and assessment of safety function indicator criteria. These criteria are a basis for formulating design premises, but they are not the same as the design premises discussed in the present report. Whereas the former should be upheld throughout the assessment period, the latter refer to the initial state and must be defined such that they give a margin for

International Expert Review of SRCan: Engineered Barrier Issues. External review contribution in support of SKI's and SSI's review of SR-Can

International Nuclear Information System (INIS)

Savage, David; Bennett, David; Apted, Mick; Saellfors, Goeran; Saario, Timo; Segle, Peter

2008-03-01

The Swedish Nuclear Fuel and Waste Management Company (SKB) has recently submitted a license application for the construction of a spent fuel encapsulation plant. SKB plans to submit a further license application in 2009 for the construction of a repository for the disposal spent nuclear fuel. In connection with the first of these applications, SKB published a safety report, known as SR-Can, which assessed the safety of a spent-fuel repository. The Swedish Nuclear Power Inspectorate (SKI) and the Swedish Radiation Protection Authority (SSI) (the Authorities) will make formal reviews of the licence applications, and have, therefore, jointly commissioned a team of independent experts to assess and provide comments on SKB's safety reports. The Authorities will consider the views of the independent review team in completing their own reviews. This document presents the comments and findings of the Engineered Barrier System (EBS) review group on SR-Can. The SR-Can safety report includes an examination of EBS design and performance for a range of scenarios, including expected repository evolution and possible variant scenarios, that together address processes and events that might result in the loss of certain repository safety functions. Furthermore, a series of sensitivity analyses is also presented that provides helpful insights into the relative importance of many key parameters and processes related to the EBS. In general, the explanatory text of the SR-Can safety report is clear, and the cited references provide adequate technical justifications for the assumptions, models, and data that are abstracted into the SR-Can safety report. The review group considers, therefore, that SKB's development of SR-Can has been a very valuable exercise, and that SKB should be congratulated on the breadth, depth and general clarity of its research and development and safety assessment programmes. Notwithstanding these successes, the EBS review group has identified a range of

International Expert Review of SRCan: Site Investigation Aspects. External review contribution in support of SKI's and SSI's review of SR-Can. INSITE/OVERSITE

International Nuclear Information System (INIS)

2008-03-01

As a first evaluation of long-term safety for KBS-3 repositories at Forsmark and Laxemar, the SIG (Site Investigation Group) found SR-Can to be a well-produced and generally well-argued safety assessment. Overall, SKB is to be complimented on this project. Members of of the two groups INSITE and OVERSITE within the SIG had somewhat differing views on how well SKB had made use of the site data available at the end of the SDM 1.2 stage of investigations. This difference is less to do with the extent of site characterisation than of its use and application, reflecting the different levels of maturity of SKB's geosphere and biosphere assessment programmes. The more recent and current work on the sites means that our concerns expressed in this review should, to a large extent, be addressable in or prior to SR-Site, provided SKB is so minded. However, we acknowledge that some of the issues we raise will not be fully resolved until underground rock characterisation from excavations or longer records of surface conditions are available. There are also some key aspects of SKB's methodology still under development that would benefit from review prior to their use in SR-Site. More space in the currently pressing schedule would allow for this review and a consequent increase in confidence. In any case, the authorities should be aware that SKB may face residual programmatic risks, associated principally with the underground design and layout (and their knockon effects into performance), even after SR-Site. An early understanding of some of these relationships would be helped by a plan (at least on an outline level) of the underground characterisation programme. We also note that many engineering matters are still to be confronted, not least the EBS design and its implementation, along with the treatment of high stresses, if Forsmark is selected. However, our views on the nature of the SR-Can analysis and the way in which site data have been utilised in it (our principal remit

The ecosystem models used for dose assessments in SR-Can

Energy Technology Data Exchange (ETDEWEB)

Avila, Rodolfo [Facilia AB, Bromma (Sweden)

2006-11-15

chronic contamination. From the simulations for the different release cases, activity concentrations in water and soil are obtained and then multiplied with the aggregated transfer factors to obtain concentrations in food products. For terrestrial ecosystems, the aggregated transfer factors in Becquerel per Kilogram of edible carbon in the food are used to calculate the activity intake and from this the effective dose rate per unit release to an adult individual. For aquatic ecosystems, only doses from the ingestion of water (for lakes) and food (for sea and lakes) are considered, as previous assessments have shown that in these types of ecosystems other exposure pathways give a very low contribution to the total doses. A sensitivity analysis of the ecosystem models is presented in the report, identifying which parameters have the largest effect on the simulation endpoints of interest. The endpoints considered are the fraction of the release that is retained in the ecosystem, the activity concentrations in soil, water and sediments, and the total dose rates from external exposure, inhalation, and ingestion of water and food. These endpoints are evaluated at different times within the simulation and a sensitivity analysis using the Morris method is carried out. For some of the scenarios considered in SR-Can, the LDF concept is not applicable. One of these scenarios comprises the contamination of ground caused by inadvertent drilling into the repository. Doses which would arise for a family using this contaminated ground for housing and food production are estimated. The other scenario which is assessed separately is the release of C-14 and Rn-222 from the repository in gaseous form, entering the biosphere via soil as a diffuse source. Pathways considered are doses from ingestion of C-14 and from inhalation of C-14 and Rn-222 outdoors as well as indoors. For these scenarios, specific dose calculations were carried out. The methods applied for these calculations and the

The ecosystem models used for dose assessments in SR-Can

International Nuclear Information System (INIS)

Avila, Rodolfo

2006-11-01

chronic contamination. From the simulations for the different release cases, activity concentrations in water and soil are obtained and then multiplied with the aggregated transfer factors to obtain concentrations in food products. For terrestrial ecosystems, the aggregated transfer factors in Becquerel per Kilogram of edible carbon in the food are used to calculate the activity intake and from this the effective dose rate per unit release to an adult individual. For aquatic ecosystems, only doses from the ingestion of water (for lakes) and food (for sea and lakes) are considered, as previous assessments have shown that in these types of ecosystems other exposure pathways give a very low contribution to the total doses. A sensitivity analysis of the ecosystem models is presented in the report, identifying which parameters have the largest effect on the simulation endpoints of interest. The endpoints considered are the fraction of the release that is retained in the ecosystem, the activity concentrations in soil, water and sediments, and the total dose rates from external exposure, inhalation, and ingestion of water and food. These endpoints are evaluated at different times within the simulation and a sensitivity analysis using the Morris method is carried out. For some of the scenarios considered in SR-Can, the LDF concept is not applicable. One of these scenarios comprises the contamination of ground caused by inadvertent drilling into the repository. Doses which would arise for a family using this contaminated ground for housing and food production are estimated. The other scenario which is assessed separately is the release of C-14 and Rn-222 from the repository in gaseous form, entering the biosphere via soil as a diffuse source. Pathways considered are doses from ingestion of C-14 and from inhalation of C-14 and Rn-222 outdoors as well as indoors. For these scenarios, specific dose calculations were carried out. The methods applied for these calculations and the

Groundwater flow and radionuclide transport modelling using CONNECTFLOW in support of the SR Can assessment

International Nuclear Information System (INIS)

Hartley, Lee; Cox, Ian; Holton, David; Hunter, Fiona; Joyce, Steve; Gylling, Bjoern; Lindgren, Maria

2004-09-01

SKB is currently pursuing site investigations for a deep repository in the municipalities of Oesthammar and Oskarshamn. The investigations are conducted in two stages; an initial phase followed by a complete site investigation phase. The favoured alternative for the location of the encapsulation plant is at Oskarshamn, where it would operate in conjunction with the existing interim storage facility. These two planning applications will each require a report on the long-term safety of the deep repository. In the case of the encapsulation plant, such a report will demonstrate that a repository for the sealed canisters will meet the requirements on long-term safety set up by the Swedish authorities. The two safety reports will be referred to as SR-Can and SR-Site, for the encapsulation plant and repository, respectively. SR-Can will be based on site data from the initial site investigation phase and SR-Site on data from the complete site investigation. The preliminary safety evaluations for each site will be carried out as sub-tasks within the SR-Can project. The main purposes of those evaluations are to: Determine whether earlier judgements of the suitability of the candidate area for a deep repository with respect to long-term safety holds up in the light of borehole data; Provide feed-back to continued site investigations and site-specific repository design. A proposed methodology for the SR-Can assessment has been published in SKB TR-03-08. The methodology envisaged the use of both continuum porous medium (CPM) and discrete fracture network (DFN) models on a range of scales to investigate the groundwater flow and radionuclide transport from a deep disposal facility to the biosphere. The modelling must address the effects of variable groundwater density and transients. Transients occur naturally as a consequence of changes in climate states (temperate, periglacial and glacial) and during the operational and immediate post-closure phases of the repository. Key

International Expert Review of SRCan: Engineered Barrier Issues. External review contribution in support of SKI's and SSI's review of SR-Can

Energy Technology Data Exchange (ETDEWEB)

Savage, David (Quintessa Limited, Henley-on-Thames (GB)); Bennett, David (TerraSalus Limited, Oakham (GB)); Apted, Mick (Monitor Scientific LLC, Denver, CO (US)); Saellfors, Goeran (Chalmers Univ. of Technology, Goeteborg (SE)); Saario, Timo (VTT Materials and Building (FI)); Segle, Peter (Inspecta, Stockholm (SE))

2008-03-15

The Swedish Nuclear Fuel and Waste Management Company (SKB) has recently submitted a license application for the construction of a spent fuel encapsulation plant. SKB plans to submit a further license application in 2009 for the construction of a repository for the disposal spent nuclear fuel. In connection with the first of these applications, SKB published a safety report, known as SR-Can, which assessed the safety of a spent-fuel repository. The Swedish Nuclear Power Inspectorate (SKI) and the Swedish Radiation Protection Authority (SSI) (the Authorities) will make formal reviews of the licence applications, and have, therefore, jointly commissioned a team of independent experts to assess and provide comments on SKB's safety reports. The Authorities will consider the views of the independent review team in completing their own reviews. This document presents the comments and findings of the Engineered Barrier System (EBS) review group on SR-Can. The SR-Can safety report includes an examination of EBS design and performance for a range of scenarios, including expected repository evolution and possible variant scenarios, that together address processes and events that might result in the loss of certain repository safety functions. Furthermore, a series of sensitivity analyses is also presented that provides helpful insights into the relative importance of many key parameters and processes related to the EBS. In general, the explanatory text of the SR-Can safety report is clear, and the cited references provide adequate technical justifications for the assumptions, models, and data that are abstracted into the SR-Can safety report. The review group considers, therefore, that SKB's development of SR-Can has been a very valuable exercise, and that SKB should be congratulated on the breadth, depth and general clarity of its research and development and safety assessment programmes. Notwithstanding these successes, the EBS review group has identified a range

SKI's and SSI's joint review of the Swedish Nuclear Fuel and Waste Management Co's (SKB) safety report SR-Can; SKIs och SSIs gemensamma granskning av SKBs saekerhetsrapport SR-Can

Energy Technology Data Exchange (ETDEWEB)

Dverstorp, Bjoern; Stroemberg, Bo (and others)

2008-03-15

This report summarizes SKI's and SSI's joint review of the Swedish Nuclear Fuel and Waste Management Co's (SKB) safety report SR-Can (SKB TR-06-09). SR-Can is the first assessment of post-closure safety for a KBS-3 spent nuclear fuel repository at the candidate sites Forsmark and Laxemar, respectively. The analysis builds on data from the initial stage of SKB's surface-based site investigations and on data from full-scale manufacturing and testing of buffer and copper canisters. SR-Can can be regarded as a preliminary version of the safety report that will be required in connection with SKB's planned license application for a final repository in late 2009. The main purpose of the authorities' review is to provide feedback to SKB on their safety reporting as part of the pre-licensing consultation process. However, SR-Can is not part of the formal licensing process. In support of the authorities' review three international peer review teams were set up to make independent reviews of SR-Can from three perspectives, namely integration of site data, representation of the engineered barriers and safety assessment methodology, respectively. Further, several external experts and consultants have been engaged to review detailed technical and scientific issues in SR-Can. The municipalities of Oesthammar and Oskarshamn where SKB is conducting site investigations, as well NGOs involved in SKB's programme, have been invited to provide their views on SR-Can as input to the authorities' review. Finally, the authorities themselves, and with the help of consultants, have used independent models to reproduce part of SKB's calculations and to make complementary calculations. All supporting review documents are published in SKI's and SSI's report series. The main findings of the review are: SKB's safety assessment methodology is overall in accordance with applicable regulations, but part of the methodology needs to be

SKI's and SSI's joint review of SKB's safety assessment report, SR 97. Summary

International Nuclear Information System (INIS)

2001-01-01

The Swedish Nuclear Fuel and Waste Management Co (SKB) has a programme for the siting of a repository for spent nuclear fuel in Swedish bedrock. In 1996, the Swedish Government decided that SKB must perform an assessment of the repository's long-term safety before undertaking the next step of the programme which entails drilling in a minimum of two municipalities (site investigations). SKB has presented such a safety assessment in SR 97 Post-closure Safety (henceforth referred to as SR 97). SR 97 is one of the documents in the comprehensive reporting that SKB must provide when it proposes sites for investigation. The Swedish Nuclear Power Inspectorate (SKI) and the Swedish Radiation Protection Institute (SSI) have evaluated SR 97 in terms of its purposes which are to demonstrate a methodology for safety assessment, to show that Swedish bedrock can provide a safe repository using SKB's method, to provide a basis for specifying the factors that are important for site selection and to derive preliminary requirements on the function of the engineered barriers. The authorities have reached the following conclusions: SR 97 does not indicate any conditions that would mean that geological final disposal in accordance with SKB's method would have significant deficiencies in relation to the safety and radiation protection requirements of the authorities. SR 97 contains the elements required for a comprehensive assessment of safety and radiation protection. SKB's safety assessment methodology has improved within several important areas, such as the documentation of processes and properties that can affect repository performance and the development of models for safety assessment calculations. The methodology used in SR 97 has some deficiencies, for example, the specification of future events to be described in the safety assessment. SR 97 has not, to an adequate extent, dealt with unfavourable conditions that can affect the future safety of a repository. SKB states that the

SR-CAN - a safety assessment of a repository of spent nuclear fuel: canister performance and effects on the biosphere

International Nuclear Information System (INIS)

Kautsky, U.; Kumblad, L.

2004-01-01

During the next few years the Swedish Nuclear Fuel and Waste Management Co. (SKB) performs site investigations at two sites in Sweden for a future repository of spent nuclear fuel. Parallel an encapsulation plant is planned to encapsulate the spent fuel in copper canisters according to the KBS-3 method. The purpose of the SR-CAN safety assessment is to show the performance of the canister isolations at different sites for a repository at 500 meters depth in crystalline rock. Moreover, SR-CAN provides an example how the site specific safety assessment of a deep repository will be made in year 2006-2008. To be able to calculate dose and risk for humans and the environment, new assessment methods were developed for the biosphere. These methods were based on a system ecological approach and used knowledge from landscape ecology to provide an integrated approach with hydrology and geology considering the discharges in a watershed and calculating consequences in terrestrial and aquatic (freshwater and marine) ecosystems. A range of methods and tools were developed in GIS and Matlab/Simulink to be able to model and understand the important processes in the landscape today and during the next few thousands of years. In this paper, an overview of the program and the novel methods are presented, as well as some examples from performance calculations from a watershed in the Forsmark area considering effects on humans and ecosystems. (author)

SKI's and SSI's review of SKB's safety report SR-Can

Energy Technology Data Exchange (ETDEWEB)

Dverstorp, Bjoern; Stroemberg, Bo (and others)

2008-03-15

This report summarises SKI's and SSI's joint review of the Swedish Nuclear Fuel and Waste Management Co's (SKB) safety report SR-Can (SKB TR-06-09). SR-Can is the first assessment of post-closure safety for a KBS-3 spent nuclear fuel repository at the candidate sites Forsmark and Laxemar, respectively. The analysis builds on data from the initial stage of SKB's surface-based site investigations and on data from full-scale manufacturing and testing of buffer and copper canisters. SR-Can can be regarded as a preliminary version of the safety report that will be required in connection with SKB's planned licence application for a final repository in late 2009. The main purpose of the authorities' review is to provide feedback to SKB on their safety reporting as part of the pre-licensing consultation process. However, SR-Can is not part of the formal licensing process. In support of the authorities' review three international peer review teams were set up to make independent reviews of SR-Can from three perspectives, namely integration of site data, representation of the engineered barriers and safety assessment methodology, respectively. Further, several external experts and consultants have been engaged to review detailed technical and scientific issues in SR-Can. The municipalities of Oesthammar and Oskarshamn where SKB is conducting site investigations, as well NGOs involved in SKB's programme, have been invited to provide their views on SR-Can as input to the authorities' review. Finally, the authorities themselves, and with the help of consultants, have used independent models to reproduce part of SKB's calculations and to make complementary calculations. All supporting review documents are published in SKI's and SSI's report series. The main findings of the review are: -SKB's safety assessment methodology is overall in accordance with applicable regulations, but part of the methodology needs to be

Radionuclide transport report for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

2010-12-15

This document compiles radionuclide transport calculations of a KBS-3 repository for the safety assessment SR-Site. The SR-Site assessment supports the licence application for a final repository at Forsmark, Sweden

Initial state report for the safety assessment SR-Can

Energy Technology Data Exchange (ETDEWEB)

Pers, Karin (ed.) [Kemakta Konsult AB, Stockholm (Sweden)

2006-10-15

A comprehensive description of the initial state of the engineered parts of the repository system is one of the main bases for the safety assessment. There is no obvious definition of the time of the initial state. For the engineered part of their repository system, the time of deposition is a natural starting point and the initial state in SR-Can is, therefore, defined as the state at the time of deposition for the engineered barrier system. The initial state of the engineered parts of the repository system is largely obtained from the design specifications of the repository, including allowed tolerances or allowance for deviations. Also the manufacturing, excavation and control methods have to be described in order to adequately discuss and handle hypothetical initial states outside the allowed limits in the design specifications. It should also be noted that many parts of the repository system are as yet not finally designed, there can be many changes in the future. The design and technical solutions presented here are representative of the current stage of development. The repository system is based on the KBS-3 method, in which copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at 400-700 m depth in saturated granitic rock. The facility design comprises rock caverns, tunnels, deposition positions etc. Deposition tunnels are linked by tunnels for transport and communication and shafts for ventilation. One ramp and five shafts connect the surface facility to the underground repository. The ramp is used for heavy and bulky transports and the shafts are for utility systems and for transport of excavated rock, backfill and staff. For the purposes of the safety assessment, the engineered parts of the repository system have been sub-divided into a number of components or sub-systems. These are: The fuel, (also including cavities in the canister since strong interactions between the two occur if the

Initial state report for the safety assessment SR-Can

International Nuclear Information System (INIS)

Pers, Karin

2006-10-01

A comprehensive description of the initial state of the engineered parts of the repository system is one of the main bases for the safety assessment. There is no obvious definition of the time of the initial state. For the engineered part of their repository system, the time of deposition is a natural starting point and the initial state in SR-Can is, therefore, defined as the state at the time of deposition for the engineered barrier system. The initial state of the engineered parts of the repository system is largely obtained from the design specifications of the repository, including allowed tolerances or allowance for deviations. Also the manufacturing, excavation and control methods have to be described in order to adequately discuss and handle hypothetical initial states outside the allowed limits in the design specifications. It should also be noted that many parts of the repository system are as yet not finally designed, there can be many changes in the future. The design and technical solutions presented here are representative of the current stage of development. The repository system is based on the KBS-3 method, in which copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at 400-700 m depth in saturated granitic rock. The facility design comprises rock caverns, tunnels, deposition positions etc. Deposition tunnels are linked by tunnels for transport and communication and shafts for ventilation. One ramp and five shafts connect the surface facility to the underground repository. The ramp is used for heavy and bulky transports and the shafts are for utility systems and for transport of excavated rock, backfill and staff. For the purposes of the safety assessment, the engineered parts of the repository system have been sub-divided into a number of components or sub-systems. These are: The fuel, (also including cavities in the canister since strong interactions between the two occur if the

International Expert Review of SRCan: Site Investigation Aspects. External review contribution in support of SKI's and SSI's review of SR-Can. INSITE/OVERSITE

Energy Technology Data Exchange (ETDEWEB)

2008-03-15

As a first evaluation of long-term safety for KBS-3 repositories at Forsmark and Laxemar, the SIG (Site Investigation Group) found SR-Can to be a well-produced and generally well-argued safety assessment. Overall, SKB is to be complimented on this project. Members of of the two groups INSITE and OVERSITE within the SIG had somewhat differing views on how well SKB had made use of the site data available at the end of the SDM 1.2 stage of investigations. This difference is less to do with the extent of site characterisation than of its use and application, reflecting the different levels of maturity of SKB's geosphere and biosphere assessment programmes. The more recent and current work on the sites means that our concerns expressed in this review should, to a large extent, be addressable in or prior to SR-Site, provided SKB is so minded. However, we acknowledge that some of the issues we raise will not be fully resolved until underground rock characterisation from excavations or longer records of surface conditions are available. There are also some key aspects of SKB's methodology still under development that would benefit from review prior to their use in SR-Site. More space in the currently pressing schedule would allow for this review and a consequent increase in confidence. In any case, the authorities should be aware that SKB may face residual programmatic risks, associated principally with the underground design and layout (and their knockon effects into performance), even after SR-Site. An early understanding of some of these relationships would be helped by a plan (at least on an outline level) of the underground characterisation programme. We also note that many engineering matters are still to be confronted, not least the EBS design and its implementation, along with the treatment of high stresses, if Forsmark is selected. However, our views on the nature of the SR-Can analysis and the way in which site data have been utilised in it (our

Is the Modern Marine 87Sr/86Sr Cycle Balanced?

Science.gov (United States)

Peucker-Ehrenbrink, B.

2017-12-01

The marine 87Sr/86Sr record is one of the best-reconstructed isotope records with thousands of high quality measurements spanning the past 800 million years. It records a global signal of tectonic, biotic and climatic processes on Earth. Yet despite decades of research we still do not know whether the current marine Sr budget is in steady state. Studies of the marine 88Sr/86Sr record indicate that sources and sinks do not balance. The magnitude and isotope composition of the terrestrial inputs are being debated, and the magnitude and temporal variability of unradiogenic contributions are not well constrained. Here I provide a revised assessment of all continental sources of Sr to the ocean, including river runoff, submarine groundwater discharge (Beck et al., 2013), dissolution of riverine suspended matter in seawater and dissolution of volcanic ash deposited on the ocean (Jones et al., 2012). I contrast continental sources of Sr with estimates of marine sources of Sr to seawater, specifically high- and low-temperature submarine hydrothermal fluids, as well as diffusive diagenetic fluxes. Best current data imply that unradiogenic submarine hydrothermal inputs to seawater are insufficient to balance the flux of radiogenic continental Sr. The revised assessment of riverine contributions is based on Sr data for almost 230 rivers, an increasing amount of time-series data for such rivers, as well as river discharge and sediment flux data for more than 2000 rivers. Regional sampling biases have been corrected with the aid of digital bedrock maps, specifically along the western margin of North America, East Africa and the large drainage region of Arabia, India and SE Asia. Significant uncertainty in the chemical and isotopic compositions of runoff from Greenland and East Africa remains. The main uncertainty in the budget, however, is related to the possibility that modern rivers do not represent the pre-anthropogenic (natural) state of continental runoff (e.g. Ganges

Opinions on SKB's Safety Assessments SR 97 and SFL 3-5. A Review by SKI Consultants

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-12-01

The Swedish Nuclear Fuel and Waste Management Co. (SKB) has presented their safety assessment 'Deep repository for spent nuclear fuel, SR 97 - Post-closure safety'. SKB's report is part of the documentation that has been required by the Government before the start of site investigations. The Swedish Nuclear Power Inspectorate (SKI) is reviewing SR 97 according to earlier Government decisions. In its review work SKI has asked several consultants, that recently have been performing research work for SKI, to give their opinions on SR 97. SKI and the Swedish Radiation Protection Institute (SSI) have used these reports from the consultants as one complementary basis for the formulation of the SKI/SSI review report. This is a compilation of the reports from the different consultants, and therefore the different contributions vary in length, style and language. Included are also two consultant reports, giving comments on SKB's preliminary safety assessment for SFL 3-5 (deep repository for long-lived low- and intermediate-level waste). The 17 contributions have all been separately indexed.

Opinions on SKB's Safety Assessments SR 97 and SFL 3-5. A Review by SKI Consultants

International Nuclear Information System (INIS)

2000-12-01

The Swedish Nuclear Fuel and Waste Management Co. (SKB) has presented their safety assessment 'Deep repository for spent nuclear fuel, SR 97 - Post-closure safety'. SKB's report is part of the documentation that has been required by the Government before the start of site investigations. The Swedish Nuclear Power Inspectorate (SKI) is reviewing SR 97 according to earlier Government decisions. In its review work SKI has asked several consultants, that recently have been performing research work for SKI, to give their opinions on SR 97. SKI and the Swedish Radiation Protection Institute (SSI) have used these reports from the consultants as one complementary basis for the formulation of the SKI/SSI review report. This is a compilation of the reports from the different consultants, and therefore the different contributions vary in length, style and language. Included are also two consultant reports, giving comments on SKB's preliminary safety assessment for SFL 3-5 (deep repository for long-lived low- and intermediate-level waste). The 17 contributions have all been separately indexed

Geosphere process report for the safety assessment SR-Site

International Nuclear Information System (INIS)

Skagius, Kristina

2010-11-01

This report documents geosphere processes identified as relevant to the long-term safety of a KBS-3 repository, and forms an important part of the reporting of the safety assessment SR-Site. The detailed assessment methodology, including the role of the process reports in the assessment, is described in the SR-Site Main report /SKB 2011/

Geosphere process report for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

Skagius, Kristina (ed.) (Kemakta Konsult AB, Stockholm (Sweden))

2010-11-15

This report documents geosphere processes identified as relevant to the long-term safety of a KBS-3 repository, and forms an important part of the reporting of the safety assessment SR-Site. The detailed assessment methodology, including the role of the process reports in the assessment, is described in the SR-Site Main report /SKB 2011/

Review of SKB's Work on Coupled THM Processes Within SR-Can. External review contribution in support of SKI's and SSI's review of SR-Can

Energy Technology Data Exchange (ETDEWEB)

Rutqvist, Jonny; Chin-Fu Tsang (Lawrence Berkeley National Laboratory, Berkeley, CA (US))

2008-03-15

In this report, we scrutinize the work by the Swedish Nuclear Fuel and Waste Management Company (SKB) related to coupled thermal, hydrological and mechanical (THM) processes within the SR-Can project. SR-Can is SKB's preliminary assessment of long-term safety for a KBS-3 nuclear waste repository, and is a preparation stage for the SR-Site assessment, the report that will be used in SKB's application for a final repository. We scrutinize SKB's work related to THM processes through review and detailed analysis, using an independent modeling tool. The modeling tool is applied to analyze coupled THM processes at the two candidate sites, Forsmark and Laxemar, using data defined in SKB's site description models for respective sites. In this report, we first provide a brief overview of SKB's work related to analysis of the evolution of coupled THM processes as presented in SRCan, as well as supporting documents. In this overview we also identify issues and assumptions that we then analyze using our modeling tool. The overview and subsequent independent model analysis addresses issues related to near-field behavior, such as buffer resaturation and the evolution of the excavation-disturbed zone, as well as far-field behavior, such as stress induced changes in hydrologic properties. Based on the review and modeling conducted in this report, we conclude by identifying a number of areas of weaknesses, where we believe further work and clarifications are needed. Some of the most important ones are summarized below: 1) We found that SKB's calculation of peak temperature might not have been conducted for the most conservative case of extreme drying of the buffer under dry rock conditions and an unexpectedly high thermal diffusion coefficient. Our alternative analysis indicates that temperatures close to 100 might be achieved under unfavorable (and perhaps unexpected) conditions in which the buffer is dried to below 20% near the canister. We believe

Using 87Sr/86Sr Ratios of Carbonate Minerals in Dust to Quantify Contributions from Desert Playas to the Urban Wasatch Front, Utah, USA

Science.gov (United States)

Goodman, M.; Carling, G. T.; Fernandez, D. P.; Rey, K.; Hale, C. A.; Nelson, S.; Hahnenberger, M.

2017-12-01

Desert playas are important dust sources globally, with potential harmful health impacts for nearby urban areas. The Wasatch Front (population >2 million) in western Utah, USA, is located directly downwind of several playas that contribute to poor air quality on dust event days. Additionally, the exposed lakebed of nearby Great Salt Lake is a growing dust source as water levels drop in response to drought and river diversions. To investigate contributions of playa dust to the Wasatch Front, we sampled dust emissions from the exposed lakebed of Great Salt Lake and seven playas in western Utah, including Sevier Dry Lake, and dust deposition at four locations stretching 160 km from south to north along the Wasatch Front, including Provo, Salt Lake City, Ogden, and Logan. The samples were analyzed for mineralogy, bulk chemistry, and 87Sr/86Sr ratios for source apportionment. The mineralogy of playa dust and Wasatch Front dust samples was dominated by quartz, feldspar, chlorite and calcite. Bulk geochemical composition was similar for all playa dust sources, with higher anthropogenic metal concentrations in the Wasatch Front. Strontium isotope (87Sr/86Sr) ratios in the carbonate fraction of the dust samples were variable in the playa dust sources, ranging from 0.7105 in Sevier Dry Lake to 0.7150 in Great Salt Lake, providing a powerful tool for apportioning dust. Based on 87Sr/86Sr mixing models, Great Salt Lake contributed 0% of the dust flux at Provo, 20% of the dust flux at Salt Lake City, and 40% of the dust flux at Ogden and Logan during Fall 2015. Contrastingly, Great Salt Lake dust was less important in Spring of 2016, contributing 0% of the dust flux at Provo and City and Logan. Two major dust events that occurred on 3 November 2015 and 23 April 2016 had similar wind and climate conditions as understood by HYSPLIT backward trajectories, meaning that seasonal variability in dust emissions is due to playa surface conditions rather than meteorologic conditions

87Sr/86Sr and 143Nd/144Nd for disentangling anthropogenic and natural REE contributions in river water during flood events.

Science.gov (United States)

Hissler, Christophe; Stille, Peter; Pfister, Laurent

2017-04-01

The sustainable management of water resources is one of the greatest challenges of the 21st century. Water is a vital resource that is increasingly put under pressure from multiple perspectives. While the global population is on the rise, socio-economic development makes equally rapid progress - eventually compromising access to clean water bodies. Multiple pollution sources constitute an immediate threat to aquatic ecosystems and are likely to cause long lasting contaminations of water bodies that are critical for drinking and/or irrigation water production. There is a pressing need for an adequate quantification of anthropogenic impacts on the critical zone of river basins and the identification of the temporal dynamics of these impacts. As an example, despite the work done to assess the environmental impact of REE pollutions in larger river systems, we are still lacking information on the dynamics of these anthropogenic compounds in relation to rapid hydrological changes. Filling these knowledge gaps is a pre-requisite for the design and implementation of sustainable water resources management strategies. In order to better constrain the relative contributions of both anthropogenic and geogenic trace element sources we propose using a multitracer approach combining elemental and 87Sr/86Sr, 143Nd/144Nd, and 206Pb/207Pb isotopic ratios. The use of these three separate isotopic systems together with REE concentrations is new in the field of anthropogenic source identification in river systems. We observed enrichments in Anthropogenic Rare Earth Elements (AREE) for dissolved Gd and suspended Nd loads of river water. With increasing discharge, AREE anomalies progressively disappeared and gave way to the geogenic chemical signature of the basin in both dissolved and suspended loads. The isotopic data confirm these observations and shed new light on the trace elements sources. On the one hand, dissolved loads have peculiar isotopic characteristics and carry mainly

Thermodynamic assessment of the Sn–Sr system supported by first-principles calculations

International Nuclear Information System (INIS)

Zhao, Jingrui; Du, Yong; Zhang, Lijun; Wang, Aijun; Zhou, Liangcai; Zhao, Dongdong; Liang, Jianlie

2012-01-01

Highlights: ► All the literature data of Sn–Sr system is critically reviewed. ► First-principles calculation of enthalpy of formation is carried out for each compound. ► Thermodynamic parameters for Sn–Sr system are obtained by CALPHAD method. ► A hybrid approach of CALPHAD and first-principles calculations is recommended. - Abstract: A hybrid approach of CALPHAD and first-principles calculations was employed to perform a thermodynamic modeling of the Sn–Sr system. The experimental phase diagram and thermodynamic data available in the literature were critically reviewed. The enthalpies of formation for the 6 stoichiometric compounds (i.e. Sr 2 Sn, Sr 5 Sn 3 , SrSn, Sr 3 Sn 5 , SrSn 3 and SrSn 4 ) at 0 K were computed by means of first-principles calculations. These data were used as the experimental values in the optimization module PARROT in the subsequent CALPHAD assessment to provide thermodynamic parameters with sound physical meaning. A set of self-consistent thermodynamic parameters was finally obtained by considering reliable literature data and the first-principles computed results. Comprehensive comparisons between the calculated and measured quantities indicate that all the reliable experimental information can be satisfactorily accounted for by the present thermodynamic description.

Opinions on SKB's Safety Assessments SR 97 and SFL 3-5. A Review by SKI Consultants

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-12-01

The Swedish Nuclear Fuel and Waste Management Co. (SKB) has presented their safety assessment 'Deep repository for spent nuclear fuel, SR 97 - Post-closure safety'. SKB's report is part of the documentation that has been required by the Government before the start of site investigations. The Swedish Nuclear Power Inspectorate (SKI) is reviewing SR 97 according to earlier Government decisions. In its review work SKI has asked several consultants, that recently have been performing research work for SKI, to give their opinions on SR 97. SKI and the Swedish Radiation Protection Institute (SSI) have used these reports from the consultants as one complementary basis for the formulation of the SKI/SSI review report. This is a compilation of the reports from the different consultants, and therefore the different contributions vary in length, style and language. Included are also two consultant reports, giving comments on SKB's preliminary safety assessment for SFL 3-5 (deep repository for long-lived low- and intermediate-level waste). The 17 contributions have all been separately indexed.

The biosphere at Laxemar. Data, assumptions and models used in the SR-Can assessment

Energy Technology Data Exchange (ETDEWEB)

Karlsson, Sara; Kautsky, Ulrik; Loefgren, Anders; Soederbaeck, Bjoern [eds.

2006-10-15

This is essentially a compilation of a variety of reports concerning the site investigations, the research activities and information derived from other sources important for the safety assessment. The main objective is to present prerequisites, methods and data used, in the biosphere modelling for the safety assessment SR-Can at the Laxemar site. A major part of the report focuses on how site-specific data are used, recalculated or modified in order to be applicable in the safety assessment context; and the methods and sub-models that are the basis for the biosphere modelling. Furthermore, the assumptions made as to the future states of surface ecosystems are mainly presented in this report. A similar report is provided for the Forsmark area. This report summarises the method adopted for safety assessment following a radionuclide release into the biosphere. The approach utilises the information about the site as far as possible and presents a way of calculating risk to humans. A central tool in the work is the description of the topography, where there is good understanding of the present conditions and the development over time is fairly predictable. The topography affects surface hydrology, sedimentation, size of drainage areas and the characteristics of ecosystems. Other parameters are human nutritional intake, which is assumed to be constant over time, and primary production (photosynthesis), which also is a fairly constant parameter over time. The Landscape Dose Factor approach (LDF) gives an integrated measure for the site and also resolves the issues relating to the size of the group with highest exposure. If this approach is widely accepted as method, still some improvements and refinement are necessary in collecting missing site data, reanalysing site data, reviewing radionuclide specific data, reformulating ecosystem models and evaluating the results with further sensitivity analysis.

The biosphere at Laxemar. Data, assumptions and models used in the SR-Can assessment

International Nuclear Information System (INIS)

Karlsson, Sara; Kautsky, Ulrik; Loefgren, Anders; Soederbaeck, Bjoern

2006-10-01

This is essentially a compilation of a variety of reports concerning the site investigations, the research activities and information derived from other sources important for the safety assessment. The main objective is to present prerequisites, methods and data used, in the biosphere modelling for the safety assessment SR-Can at the Laxemar site. A major part of the report focuses on how site-specific data are used, recalculated or modified in order to be applicable in the safety assessment context; and the methods and sub-models that are the basis for the biosphere modelling. Furthermore, the assumptions made as to the future states of surface ecosystems are mainly presented in this report. A similar report is provided for the Forsmark area. This report summarises the method adopted for safety assessment following a radionuclide release into the biosphere. The approach utilises the information about the site as far as possible and presents a way of calculating risk to humans. A central tool in the work is the description of the topography, where there is good understanding of the present conditions and the development over time is fairly predictable. The topography affects surface hydrology, sedimentation, size of drainage areas and the characteristics of ecosystems. Other parameters are human nutritional intake, which is assumed to be constant over time, and primary production (photosynthesis), which also is a fairly constant parameter over time. The Landscape Dose Factor approach (LDF) gives an integrated measure for the site and also resolves the issues relating to the size of the group with highest exposure. If this approach is widely accepted as method, still some improvements and refinement are necessary in collecting missing site data, reanalysing site data, reviewing radionuclide specific data, reformulating ecosystem models and evaluating the results with further sensitivity analysis

Fuel and canister process report for the safety assessment SR-Site

International Nuclear Information System (INIS)

Werme, Lars; Lilja, Christina

2010-12-01

This report documents fuel and canister processes identified as relevant to the long-term safety of a KBS-3 repository. It forms an important part of the reporting of the safety assessment SR-Site. The detailed assessment methodology, including the role of the process reports in the assessment, is described in the SR-Site Main report /SKB 2011/

Fuel and canister process report for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

Werme, Lars; Lilja, Christina (eds.)

2010-12-15

This report documents fuel and canister processes identified as relevant to the long-term safety of a KBS-3 repository. It forms an important part of the reporting of the safety assessment SR-Site. The detailed assessment methodology, including the role of the process reports in the assessment, is described in the SR-Site Main report /SKB 2011/

Human SR-BII mediates SAA uptake and contributes to SAA pro-inflammatory signaling in vitro and in vivo.

Directory of Open Access Journals (Sweden)

Irina N Baranova

Full Text Available Serum amyloid A (SAA is an acute phase protein with cytokine-like and chemotactic properties, that is markedly up-regulated during various inflammatory conditions. Several receptors, including FPRL-1, TLR2, TLR4, RAGE, class B scavenger receptors, SR-BI and CD36, have been identified as SAA receptors. This study provides new evidence that SR-BII, splice variant of SR-BI, could function as an SAA receptor mediating its uptake and pro-inflammatory signaling. The uptake of Alexa Fluor488 SAA was markedly (~3 fold increased in hSR-BII-expressing HeLa cells when compared with mock-transfected cells. The levels of SAA-induced interleukin-8 secretion by hSR-BII-expressing HEK293 cells were also significantly (~3-3.5 fold higher than those detected in control cells. Moderately enhanced levels of phosphorylation of all three mitogen-activated protein kinases, ERK1/2, and p38 and JNK, were observed in hSR-BII-expressing cells following SAA stimulation when compared with control wild type cells. Transgenic mice with pLiv-11-directed liver/kidney overexpression of hSR-BI or hSR-BII were used to assess the in vivo role of each receptor in SAA-induced pro-inflammatory response in these organs. Six hours after intraperitoneal SAA injection both groups of transgenic mice demonstrated markedly higher (~2-5-fold expression levels of inflammatory mediators in the liver and kidney compared to wild type mice. Histological examinations of hepatic and renal tissue from SAA-treated mice revealed moderate level of damage in the liver of both transgenic but not in the wild type mice. Activities of plasma transaminases, biomarkers of liver injury, were also moderately higher in hSR-B transgenic mice when compared to wild type mice. Our findings identify hSR-BII as a functional SAA receptor that mediates SAA uptake and contributes to its pro-inflammatory signaling via the MAPKs-mediated signaling pathways.

Data and uncertainty assessment for radionuclide Kd partitioning coefficients in granitic rock for use in SR-Can calculations

International Nuclear Information System (INIS)

Crawford, James; Neretnieks, Ivars; Malmstroem, Maria

2006-10-01

SKB is currently preparing licence applications related to the proposed deep repository for spent nuclear fuel as well as the encapsulation plant required for canister fabrication. The present report is one of several specific data reports that form the data input to an interim safety report (SR-Can) for the encapsulation plant licence application. This report concerns the derivation and recommendation of generic K d data (i.e. linear partitioning coefficients) for safety assessment modelling of far-field radionuclide transport in fractured granitic rock. The data are derived for typical Swedish groundwater conditions and rock types distinctive of those found on the Simpevarp peninsula and Forsmark. Data have been derived for 8 main elements (Cs, Sr, Ra, Ni, Th, U, Np, Am) and various oxidation states. The data have also been supplied with tentative correction factors to account for artefacts that have not been previously considered in detail in previous compilations. For the main reviewed solutes the data are given in terms of a best estimate K d value assumed to be the median of the aggregate set of selected data. A range corresponding to the 25-75% inter-quartile range is also specified and probable ranges of uncertainty are estimated in the form of an upper and lower limit to the expected variability. Data for an additional 19 elements that have not been reviewed are taken from a previous compilation by Carbol and Engkvist

Review of SKB's interim report of SR-Can: SKI's and SSI's evaluation of SKB's up-dated methodology for safety assessment

International Nuclear Information System (INIS)

Dverstorp, Bjoern; Moberg, Leif; Wiebert, Anders; Xu Shulan; Stroemberg, Bo; Kautsky, Fritz; Lilja, Christina; Simic, Eva; Sundstroem, Benny; Toverud, Oeivind

2005-07-01

This report presents the findings of a review of the Swedish Nuclear Fuel and Waste Management Co.'s (SKB) interim report of the safety assessment SR-Can (SKB TR 04-11), conducted by the Swedish Radiation Protection Authority (SSI) and the Swedish Nuclear Power Inspectorate (SKI). SKB's interim report describes and exemplifies the safety assessment methodology that SKB plans to use in the oncoming licence applications for an encapsulation plant and a final repository for spent nuclear fuel. The authorities' review takes into account the findings of an international peer review of SKB's interim report. The authorities conclude that SKB has improved its safety assessment methodology in several aspects compared to earlier safety reports. Among other things the authorities commend SKB for giving a comprehensive account of relevant regulations and guidance, and for the systematic approach to identification and documentation of features, events and processes that need to be considered in the safety assessment. However, the authorities also conclude that important parts of SKB's method need to be further developed before they are mature enough to be used as a basis for a license application. The authorities' overall assessment is summarised in chapter 8 of this report

Development of Landscape Dose Factors for dose assessments in SR-Can

Energy Technology Data Exchange (ETDEWEB)

Avila, Rodolfo; Ekstroem, Per-Anders [Facilia AB, Bromma (Sweden); Kautsky, Ulrik [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

2006-08-15

In previous safety assessments Ecosystem Dose Factors (EDFs), were derived from estimates of doses to the most exposed group resulting from constant unit radionuclide release rates over 10,000 years to various ecosystem types, e.g. mires, agricultural lands, lakes and marine ecosystems. A number of limitations of the EDF approach have been identified. The objectives of this report is to further develop the EDF approach, in order to resolve the identified limitations, and to use the improved approach for deriving Dose Conversion Factors for use in the SR-Can risk assessments. The Dose Conversion Factors derived in this report are named Landscape Dose Factors (LDFs). It involves modelling the fate of the radionuclides in the whole landscape, which develops from a sea to a inland situation during 20,000 years. Both candidate sites studies in SR-Can, Forsmark and Laxemar, are included in the study. As a basis for the modelling, the period starting at the beginning of the last interglacial (8,000 BC) is used, over which releases from a hypothetical repository were assumed to take place. For the present temperate period, the overall development of the biosphere at each site is outlined in a 1,000 year perspective and beyond, essentially based on the ongoing shoreline displacement and the understanding on the impact this has on the biosphere. The past development, i.e. from deglaciation to the present time, is inferred from geological records and associated reconstructions of the shore-line. For each time step of 1,000 years, the landscape at the site is described as a number of interconnected biosphere objects constituting an integrated landscape model of each site. The water fluxes through the objects were estimated from the average run-off at the site, the areas of the objects and their associated catchment areas. Radionuclides in both dissolved and particulate forms were considered in the transport calculations. The transformation between ecosystems was modelled as

How social impact assessment can contribute to conflict management

International Nuclear Information System (INIS)

Prenzel, Paula V.; Vanclay, Frank

2014-01-01

The potential for conflict is omnipresent in all projects, and even in all human interactions, and conflict itself leads to many second-order social impacts. This article examines the contribution of the methodological approach used in social impact assessment (SIA) to conflict management. We view conflict as a process that has its own dynamic, and is to be expected in all situations. By using game theory (prisoner's dilemma), we describe and conceptualize this process and highlight the importance of communication in managing conflict. We demonstrate the potential use of SIA in preventing, managing and resolving conflict. Emphasis is placed on the participatory character of SIA and the role of public media. In contrast to existing literature, our focus is not restricted to the typical fields of study of SIA (e.g. environmental conflicts), but understands conflict itself as a field of application. In this sense, conflict-sensitive SIA can be understood both as an extension to the SIA tool kit and a broadening of the scope of SIA application. -- Highlights: • Conflict is omnipresent and creates both positive and negative social impacts. • Conflict itself represents a possible field of application for SIA. • Conflict escalation is a process that can be modeled in a game-theoretic framework. • There needs to be concerted effort to prevent escalation to avoid harmful outcomes. • Conflict-sensitive SIA can support conflict management and sustainable resolution

How social impact assessment can contribute to conflict management

Energy Technology Data Exchange (ETDEWEB)

Prenzel, Paula V., E-mail: p.v.prenzel@student.rug.nl; Vanclay, Frank, E-mail: frank.vanclay@rug.nl

2014-02-15

The potential for conflict is omnipresent in all projects, and even in all human interactions, and conflict itself leads to many second-order social impacts. This article examines the contribution of the methodological approach used in social impact assessment (SIA) to conflict management. We view conflict as a process that has its own dynamic, and is to be expected in all situations. By using game theory (prisoner's dilemma), we describe and conceptualize this process and highlight the importance of communication in managing conflict. We demonstrate the potential use of SIA in preventing, managing and resolving conflict. Emphasis is placed on the participatory character of SIA and the role of public media. In contrast to existing literature, our focus is not restricted to the typical fields of study of SIA (e.g. environmental conflicts), but understands conflict itself as a field of application. In this sense, conflict-sensitive SIA can be understood both as an extension to the SIA tool kit and a broadening of the scope of SIA application. -- Highlights: • Conflict is omnipresent and creates both positive and negative social impacts. • Conflict itself represents a possible field of application for SIA. • Conflict escalation is a process that can be modeled in a game-theoretic framework. • There needs to be concerted effort to prevent escalation to avoid harmful outcomes. • Conflict-sensitive SIA can support conflict management and sustainable resolution.

Long-term safety for KBS-3 repositories at Forsmark and Laxemar - a first evaluation. Main Report of the SR-Can project

International Nuclear Information System (INIS)

Hedin, Allan

2006-10-01

This document is the main report from the safety assessment project SR-Can. The SR-Can project is a preparatory stage for the SR-Site assessment, the report that will be used in support of SKB's application for a final repository. The purposes of the safety assessment SR-Can are the following: 1. To make a first assessment of the safety of potential KBS-3 repositories at Forsmark and Laxemar to dispose of canisters as specified in the application for the encapsulation plant. 2. To provide feedback to design development, to SKB's RandD programme, to further site investigations and to future safety assessment projects. 3. To foster a dialogue with the authorities that oversee SKB's activities, i.e. the Swedish Nuclear Power Inspectorate, SKI, and the Swedish Radiation Protection Authority, SSI, regarding interpretation of applicable regulations, as a preparation for the SR-Site project. The assessment relates to the KBS-3 disposal concept in which copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at approximately 500 m depth in saturated, granitic rock. Preliminary data from the Forsmark and Laxemar sites, presently being investigated by SKB as candidates for a KBS-3 repository are used in the assessment. An important aim of this report is to demonstrate the proper handling of requirements placed on the safety assessment in applicable regulations. Therefore, regulations issued by the Swedish Nuclear Power Inspectorate and the Swedish Radiation Protection Institute are reproduced in an Appendix where references are given to sections in the main text where the handling of the different requirements is discussed. The principal acceptance criterion requires that 'the annual risk of harmful effects after closure does not exceed 10 -6 for a representative individual in the group exposed to the greatest risk'. 'Harmful effects' refer to cancer and hereditary effects. The risk limit corresponds to an

Long-term safety for KBS-3 repositories at Forsmark and Laxemar - a first evaluation. Main Report of the SR-Can project

Energy Technology Data Exchange (ETDEWEB)

Hedin, Allan (ed.)

2006-10-15

This document is the main report from the safety assessment project SR-Can. The SR-Can project is a preparatory stage for the SR-Site assessment, the report that will be used in support of SKB's application for a final repository. The purposes of the safety assessment SR-Can are the following: 1. To make a first assessment of the safety of potential KBS-3 repositories at Forsmark and Laxemar to dispose of canisters as specified in the application for the encapsulation plant. 2. To provide feedback to design development, to SKB's RandD programme, to further site investigations and to future safety assessment projects. 3. To foster a dialogue with the authorities that oversee SKB's activities, i.e. the Swedish Nuclear Power Inspectorate, SKI, and the Swedish Radiation Protection Authority, SSI, regarding interpretation of applicable regulations, as a preparation for the SR-Site project. The assessment relates to the KBS-3 disposal concept in which copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at approximately 500 m depth in saturated, granitic rock. Preliminary data from the Forsmark and Laxemar sites, presently being investigated by SKB as candidates for a KBS-3 repository are used in the assessment. An important aim of this report is to demonstrate the proper handling of requirements placed on the safety assessment in applicable regulations. Therefore, regulations issued by the Swedish Nuclear Power Inspectorate and the Swedish Radiation Protection Institute are reproduced in an Appendix where references are given to sections in the main text where the handling of the different requirements is discussed. The principal acceptance criterion requires that 'the annual risk of harmful effects after closure does not exceed 10{sup -6} for a representative individual in the group exposed to the greatest risk'. 'Harmful effects' refer to cancer and hereditary effects

Model summary report for the safety assessment SR-Site

International Nuclear Information System (INIS)

Vahlund, Fredrik; Zetterstroem Evins, Lena; Lindgren, Maria

2010-12-01

This document is the model summary report for the safety assessment SR-Site. In the report, the quality assurance (QA) measures conducted for assessment codes are presented together with the chosen QA methodology. In the safety assessment project SR-Site, a large number of numerical models are used to analyse the system and to show compliance. In order to better understand how the different models interact and how information are transferred between the different models Assessment Model Flowcharts, AMFs, are used. From these, different modelling tasks can be identify and the computer codes used. As a large number of computer codes are used in the assessment the complexity of these differs to a large extent, some of the codes are commercial while others are developed especially for the assessment at hand. QA requirements must on the one hand take this diversity into account and on the other hand be well defined. In the methodology section of the report the following requirements are defined for all codes: - It must be demonstrated that the code is suitable for its purpose. - It must be demonstrated that the code has been properly used. - It must be demonstrated that the code development process has followed appropriate procedures and that the code produces accurate results. - It must be described how data are transferred between the different computational tasks. Although the requirements are identical for all codes in the assessment, the measures used to show that the requirements are fulfilled will be different for different types of codes (for instance due to the fact that for some software the source-code is not available for review). Subsequent to the methodology section, each assessment code is presented together with a discussion on how the requirements are met

Model summary report for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

Vahlund, Fredrik; Zetterstroem Evins, Lena (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Lindgren, Maria (Kemakta Konsult AB, Stockholm (Sweden))

2010-12-15

This document is the model summary report for the safety assessment SR-Site. In the report, the quality assurance (QA) measures conducted for assessment codes are presented together with the chosen QA methodology. In the safety assessment project SR-Site, a large number of numerical models are used to analyse the system and to show compliance. In order to better understand how the different models interact and how information are transferred between the different models Assessment Model Flowcharts, AMFs, are used. From these, different modelling tasks can be identify and the computer codes used. As a large number of computer codes are used in the assessment the complexity of these differs to a large extent, some of the codes are commercial while others are developed especially for the assessment at hand. QA requirements must on the one hand take this diversity into account and on the other hand be well defined. In the methodology section of the report the following requirements are defined for all codes: - It must be demonstrated that the code is suitable for its purpose. - It must be demonstrated that the code has been properly used. - It must be demonstrated that the code development process has followed appropriate procedures and that the code produces accurate results. - It must be described how data are transferred between the different computational tasks. Although the requirements are identical for all codes in the assessment, the measures used to show that the requirements are fulfilled will be different for different types of codes (for instance due to the fact that for some software the source-code is not available for review). Subsequent to the methodology section, each assessment code is presented together with a discussion on how the requirements are met

International Peer Review of Swedish Nuclear Fuel and Waste Management Company's SR-Can interim report

International Nuclear Information System (INIS)

Sagar, Budhi; Bailey, Lucy; Bennett, David G.; Egan, Mike; Roehlig, Klaus

2004-12-01

SKB has produced an interim safety assessment report as part of its work to develop a licence application for the construction of a spent nuclear fuel encapsulation plant. The purpose of the interim report is to set out and demonstrate SKB's proposed methodology for long-term safety assessment. The aim of producing an interim report is to allow the Swedish regulatory authorities (SKI and SSI) to review and comment on SKB's proposed methodology before it is used in support of a formal licence application. To help inform their review of SKB's proposed methodology, the authorities appointed an international review team (IRT) to carry out a review of SKB's interim safety assessment report. Comments from the IRT are presented in this document and will be considered by the regulatory authorities in developing their own view of SKB's proposed methodology. The IRT's review included examination of SKB's documentation (the 'Interim Main Report of the Safety Assessment SR-Can' and four supporting documents) and hearings with SKB staff and contractors. The hearings provided an opportunity for the IRT to discuss the SR-Can safety assessment with the authors and contributors to SKB's work. As directed by SKI and SSI, the IRT's review focused on methodological aspects and sought to determine whether SKB's proposed safety assessment methodology: (i) is fit for the purpose of supporting a licence application; (ii) has a reasonable prospect of leading to a safety assessment that is sufficiently comprehensive, reproducible, traceable and transparent; (iii) is compatible with the authorities' regulations and guidance. No evaluation of long term safety or site acceptability was attempted by the IRT. At the request of SKI and SSI, the IRT's review considered and made recommendations on the following issues: Description of the initial state of the repository and its components; Description of features, events and processes (FEPs) relevant to repository evolution; Strategy for safety

Climate and climate-related issues for the safety assessment SR-Site

International Nuclear Information System (INIS)

2010-12-01

The purpose of this report is to document current scientific knowledge on climate and climate-related conditions, relevant to the long-term safety of a KBS-3 repository, to a level required for an adequate treatment in the safety assessment SR-Site. The report also presents a number of dedicated studies on climate and selected climate-related processes of relevance for the assessment of long term repository safety. Based on this information, the report presents a number of possible future climate developments for Forsmark, the site selected for building a repository for spent nuclear fuel in Sweden (Figure 1-1). The presented climate developments are used as basis for the selection and analysis of SR-Site safety assessment scenarios in the SR-Site main report /SKB 2011/. The present report is based on research conducted and published by SKB as well as on research reported in the general scientific literature

Climate and climate-related issues for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

2010-12-15

The purpose of this report is to document current scientific knowledge on climate and climate-related conditions, relevant to the long-term safety of a KBS-3 repository, to a level required for an adequate treatment in the safety assessment SR-Site. The report also presents a number of dedicated studies on climate and selected climate-related processes of relevance for the assessment of long term repository safety. Based on this information, the report presents a number of possible future climate developments for Forsmark, the site selected for building a repository for spent nuclear fuel in Sweden (Figure 1-1). The presented climate developments are used as basis for the selection and analysis of SR-Site safety assessment scenarios in the SR-Site main report /SKB 2011/. The present report is based on research conducted and published by SKB as well as on research reported in the general scientific literature

Thermodynamic assessment of the Pb-Sr system

Directory of Open Access Journals (Sweden)

Zhang H.

2017-01-01

Full Text Available The Pb-Sr system has been critically reviewed and modeled by means of the CALPHAD (CALculation of PHAse Diagrams approach. It contains seven stoichiometric compounds, i.e. SrPb3, Sr3Pb5, Sr2Pb3, SrPb, Sr5Pb4, Sr5Pb3 and Sr2Pb, in which the SrPb3 and Sr2Pb phases melt congruently, and the other five phases form via peritectic reactions. The enthalpies of formation for the intermetallic compounds at 0 K are provided by first-principles calculations. The liquid, fcc and bcc phases are modeled as substitutional solution phases. Both Redlich-Kister and exponential polynomials are used to describe the excess Gibbs energy of the liquid. Two sets of self-consistent thermodynamic parameters are obtained by considering reliable experimental data and the computed enthalpies of formation. Comprehensive comparisons between the calculated and measured phase diagram and thermodynamic data show that the experimental information is satisfactorily accounted for by the present thermodynamic description.

Data and uncertainty assessment for radionuclide K{sub d} partitioning coefficients in granitic rock for use in SR-Can calculations

Energy Technology Data Exchange (ETDEWEB)

Crawford, James; Neretnieks, Ivars; Malmstroem, Maria [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Chemical Engineering and Technology

2006-10-15

SKB is currently preparing licence applications related to the proposed deep repository for spent nuclear fuel as well as the encapsulation plant required for canister fabrication. The present report is one of several specific data reports that form the data input to an interim safety report (SR-Can) for the encapsulation plant licence application. This report concerns the derivation and recommendation of generic K{sub d} data (i.e. linear partitioning coefficients) for safety assessment modelling of far-field radionuclide transport in fractured granitic rock. The data are derived for typical Swedish groundwater conditions and rock types distinctive of those found on the Simpevarp peninsula and Forsmark. Data have been derived for 8 main elements (Cs, Sr, Ra, Ni, Th, U, Np, Am) and various oxidation states. The data have also been supplied with tentative correction factors to account for artefacts that have not been previously considered in detail in previous compilations. For the main reviewed solutes the data are given in terms of a best estimate K{sub d} value assumed to be the median of the aggregate set of selected data. A range corresponding to the 25-75% inter-quartile range is also specified and probable ranges of uncertainty are estimated in the form of an upper and lower limit to the expected variability. Data for an additional 19 elements that have not been reviewed are taken from a previous compilation by Carbol and Engkvist.

Sequential separation of cs, ca and ba for 90sr assessment

International Nuclear Information System (INIS)

Dianu, M.; Bucur, C.

2015-01-01

A two-steps chemical treatment technique for strontium assessment from aqueous samples is described in this paper. The method was applied to simulated samples containing stable elements of Ni, Cs, Ca, Ba, Mn, Fe, Co and Eu. The transition elements (Ni, Mn, Fe, Co, Eu) were precipitated as hydroxides, followed by alkaline-earth metals separation (Ca, Ba) as carbonates. Finally, the Sr was purified by extraction chromatography using Triskem International Sr resin. The strength of Sr sorption in nitric acid increases with increasing acid concentration, and the optimal bonding strength is achieved in 8 M HNO3. The combination of successive precipitations with extraction chromatography for complete removal of other interferences from Sr matrix leads to good recovery and decontamination factor values. (authors)

87Sr/86Sr isotope fingerprinting of Scottish and Icelandic migratory shorebirds

International Nuclear Information System (INIS)

Evans, Jane; Bullman, Rhys

2009-01-01

Biosphere Sr isotope composition data from Iceland and Scotland suggest that terrestrially feeding birds from these two countries will have significantly different 87 Sr/ 86 Sr isotope composition in their tissues. The aim of this study is to test if these differences can be measured within the bone and feather of migratory wading birds, who feed terrestrially as juveniles, thus providing a provenance tool for these birds. The study shows that birds can be distinguished on the basis of the Sr isotope composition of their bone. The field for Icelandic birds is defined by data from juvenile common redshank (Tringa totanus) and whimbrel (Numenius phaeopus) which give 0.7056 ± 0.0012, (2σ, n = 7). The majority of Scottish birds in this study are from coastal regions and have a signature close to that of seawater of 0.7095 ± 0.0006 (2σ, n = 9). The Sr ratios in the body tissue of these two populations of all Icelandic and Scottish adult and juvenile birds analysed are significantly different (p 87 Sr/ 86 Sr values as high as 0.7194 which reflect their non-marine diet. Icelandic redshank (Tringa totanus robusta) that have flown to Scotland and returned to Iceland show the effect of the Scottish contribution to their diet with elevated values of 0.7086 ± 0.0004, (2σ, n = 6). Redshank found in Scotland that cannot be classified on the basis biometric analysis are shown to be of Icelandic origin and analysis of the primary feathers from two birds demonstrates that isotope variation between feathers could be used to track changes in diet related to the timing of individual feather growth.

Chemical weathering on the North Island of New Zealand: CO2 consumption and fluxes of Sr and Os

Science.gov (United States)

Blazina, Tim; Sharma, Mukul

2013-09-01

We present Os and Sr isotope ratios and Os, Sr and major/trace element concentrations for river waters, spring waters and rains on the North Island of New Zealand. The Os and Sr data are used to examine whether the NINZ is a significant contributor of unradiogenic Os and Sr to the oceans. Major element chemistry is used to quantify weathering and CO2 consumption rates on the island to investigate relationships between these processes and Os and Sr behavior. Chemical erosion rates and CO2 consumption rates across the island range from 44 to 555 km-2 yr-1 and 95 to 1900 × 103 mol CO2 km-2 yr-1, respectively. Strontium flux for the island range from 177 to 16,100 mol km-2 yr-1 and the rivers have an average flux normalized 87Sr/86Sr ratio of 0.7075. In agreement with the previous studies these findings provide further evidence that weathering of arc terrains contributes a disproportionally large amount of Sr to the oceans and consumes very large amounts of CO2 annually compared to their areal extent. However, the 87Sr/86Sr from the NINZ is not particularly unradiogenic and it is likely not contributing significant amounts of unradiogenic Sr to the oceans. Repeated Os analyses and bottle leaching experiments revealed extensive and variable sample contamination by Os leaching from rigorously precleaned LDPE bottles. An upper bound on the flux of Os from NINZ can nevertheless be assessed and indicates that island arcs cannot provide significant amounts of unradiogenic Os to the oceans.

Data report for the safety assessment SR-Site

International Nuclear Information System (INIS)

2010-12-01

This report compiles, documents, and qualifies input data identified as essential for the long-term safety assessment of a KBS-3 repository, and forms an important part of the reporting of the safety assessment project SR-Site. The input data concern the repository system, broadly defined as the deposited spent nuclear fuel, the engineered barriers surrounding it, the host rock, and the biosphere in the proximity of the repository. The input data also concern external influences acting on the system, in terms of climate related data. Data are provided for a selection of relevant conditions and are qualified through traceable standardised procedures

Data report for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

2010-12-15

This report compiles, documents, and qualifies input data identified as essential for the long-term safety assessment of a KBS-3 repository, and forms an important part of the reporting of the safety assessment project SR-Site. The input data concern the repository system, broadly defined as the deposited spent nuclear fuel, the engineered barriers surrounding it, the host rock, and the biosphere in the proximity of the repository. The input data also concern external influences acting on the system, in terms of climate related data. Data are provided for a selection of relevant conditions and are qualified through traceable standardised procedures

Development of 87Sr/86Sr maps as targeted strategy to support wine quality.

Science.gov (United States)

Durante, Caterina; Bertacchini, Lucia; Cocchi, Marina; Manzini, Daniela; Marchetti, Andrea; Rossi, Maria Cecilia; Sighinolfi, Simona; Tassi, Lorenzo

2018-07-30

This study summarizes the results obtained from a systematic and long-term project aimed at the development of tools to assess the provenance of food in the oenological sector. In particular, 87 Sr/ 86 Sr isotope ratios were measured on statistically representative set of soils, vine branches and wines sampled in the production district of Modena, worldwide known for the Lambrusco wines production. The obtained data were used to build strontium isotopic maps able to objectively support the Lambrusco PDO wines origin as well as other products of the Modena district. Finally, a strong relationship was found between the 87 Sr/ 86 Sr isotope ratios of soils and vine branches on a large scale, highlighting and confirming once more the idea that plants can also represent an optimal sampling device to support geographical traceability. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assessment of the Mechanisms for Sr-90 and TRU Removal from Complexant-Containing Tank Wastes at Hanford

International Nuclear Information System (INIS)

Hallen, Richard T.; Geeting, John GH; Lilga, Michael A.; Hart, Todd R.; Hoopes, Francis V.

2005-01-01

Small-scale tests (∼20 mL) were conducted with samples from Hanford underground storage tanks AN-102 and AN-107 to assess the mechanisms for removing Sr-90 and transuranics (TRU) from the liquid (supernatant) portion of the waste. The Sr-90 and TRU must be removed (decontaminated), in addition to Cs-137 and the entrained solids, before the supernatant can be disposed of as low-activity waste. Experiments were conducted with various reagents and modified Sr/TRU removal process conditions to more fully understand the reaction mechanisms. The optimized treatment conditions--no added hydroxide, addition of Sr (0.02M target concentration) followed by sodium permanganate (0.02M target concentration) with mixing at ambient temperature--were used as a reference for comparison. The waste was initially two orders of magnitude undersaturated with Sr; the addition of nonradioactive Sr(NO?) ? saturated the supernatant, resulting in isotopic dilution and precipitation of Sr-90 as SrCO?. The reaction chemistry of Mn species relevant to the mechanism of TRU removal by permanganate treatment was evaluated, along with the importance of various mechanisms for decontamination, such as precipitation, absorption, ligand exchange, and oxidation of organic complexants. For TRU removal, permanganate addition generally gave the highest DF. The addition of Mn of lower oxidation states (II, IV, and VI) also resulted in good TRU removal, as did complexant oxidation with periodate and addition of Zr(IV) for ligand exchange. These results suggest that permanganate treatment leads to TRU removal by multiple routes

Changes in local surface structure and Sr depletion in Fe-implanted SrTiO{sub 3} (001)

Energy Technology Data Exchange (ETDEWEB)

Lobacheva, O., E-mail: olobache@gmail.com [Department of Physics and Astronomy, Western University, London, ON N6A 5B7 (Canada); Yiu, Y.M. [Department of Chemistry, Western University, London, ON N6A 5B7 (Canada); Chen, N. [Canadian Light Source, Saskatoon, SK S7N 0X4 (Canada); Sham, T.K.; Goncharova, L.V. [Department of Physics and Astronomy, Western University, London, ON N6A 5B7 (Canada); Department of Chemistry, Western University, London, ON N6A 5B7 (Canada)

2017-01-30

Highlights: • Fe ion implantation of SrTiO{sub 3} and post-implantation results in formation of Sr{sub 1-y}Ti{sub 1-x}Fe{sub x+y}O{sub 3-δ} phase. • In Sr{sub 1-y}Ti{sub 1-x}Fe{sub x+y}O{sub 3-δ} phase, Fe assumes Fe{sup 3+} oxidation state in the bulk and Fe{sup 2+} oxidation state in the near surface area. • FEFF9 calculations indicate that Fe ions can substitute both Ti and Sr sites. • Formation of Sr{sub 1-y}Ti{sub 1-x}Fe{sub x+y}O{sub 3-δ} phase is accompanied by Sr depletion in the near surface region. - Abstract: Local surface structure of single crystal strontium titanate SrTiO{sub 3} (001) samples implanted with Fe in the range of concentrations between 2 × 10{sup 14} to 2 × 10{sup 16} Fe/cm{sup 2} at 30 keV has been investigated. In order to facilitate Fe substitution (doping), implanted samples were annealed in oxygen at 350 °C. Sr depletion was observed from the near-surface layers impacted by the ion-implantation process, as revealed by Rutherford Backscattering Spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray Absorption Near Edge Spectroscopy (XANES), and Atomic Force Microscopy (AFM). Hydrocarbon contaminations on the surface may contribute to the mechanisms of Sr depletion, which have important implications for Sr(Ti{sub 1-x}Fe{sub x})O{sub 3-δ} materials in gas sensing applications.

Review comments on the SR 97 post-closure safety assessment

International Nuclear Information System (INIS)

Geier, J.

2000-01-01

These review comments concern an assessment of the long-term safety of a deep repository for spent nuclear fuel, titled Safety Report 97 (SR 97), which was prepared by the Swedish Nuclear Fuel Waste Management Company (SKB). The primary focus of this review is on hydrogeologic issues relating to groundwater flow, hydrologic uncertainty, and the potential for radionuclide transport from leaking canisters. The main hydrological model that was used in SR 97 is based on a continuum conceptual model of groundwater flow in fractured bedrock. Major problems with this model include the following: The validity of the continuum model is arguable for the type of rock that is present at these sites. The suitability of the model for the intended purpose of predicting streamlines and travel times for groundwater flow through the rock mass has not been adequately demonstrated. The comparison with alternative, discrete models yielded more divergent results than has been recognized in the SR 97 reports. The comparison with alternative models did not consider significant, realistic sources of uncertainty in the alternative models, evaluation of which would have likely led to greater divergence. The SR 97 model of radionuclide transport is based on a 1-D streamtube formulation, within which the predicted release of radionuclides to the biosphere is dominated by a parameter called the F ratio. A key factor in this parameter is the flow wetted surface. All of the hydrologic models used in SR 97 relied upon essentially the same set of geometric assumptions to estimate flow wetted surface from conductive fracture frequency in boreholes. Hence the predictions of the alternative models are not independent. Alternative methods of estimating flow wetted surface are needed to obtain a realistic evaluation of the uncertainty regarding radionuclide release. The alternative 3-D hydrologic models were used only to predict streamtube parameters, not for actual transport simulations. Hence the

Environmental levels of 239+240Pu and 90Sr for internal radiation exposure assessment

International Nuclear Information System (INIS)

Anand, S.J.S.; Khandekar, R.N.; Krishnamoorthy, T.M.

1995-01-01

Measurements have been carried out on the concentration of low levels of long-lived isotopes of 239+240 Pu and 90 Sr in the environmental materials such as atmospheric particulates, drinking water and food. The estimation of daily intake of these isotopes through inhalation and ingestion is a pre-requisite for the assessment of internal exposure. This paper presents temporal distribution of 239+240 Pu and 90 Sr in rain water, drinking water and total diet samples collected at Trombay site. The annual committed effective dose due to 90 Sr through inhalation and diet to the population of Bombay has been estimated to be 0.06 nSv/y and 0.48 μSv/y, respectively, and the same for 239+240 Pu is 1.3 nSv/y and 0.9 nSv/y, respectively. The data is discussed in relation to previous years' values to assess for any significant increase. (author). 9 refs., 3 figs., 2 tabs

Assessing electron beam sensitivity for SrTiO{sub 3} and La{sub 0.7}Sr{sub 0.3}MnO{sub 3} using electron energy loss spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Nord, Magnus, E-mail: magnunor@gmail.com [Department of Physics, NTNU, Trondheim (Norway); Vullum, Per Erik [Department of Physics, NTNU, Trondheim (Norway); Materials and Chemistry, SINTEF, Trondheim (Norway); Hallsteinsen, Ingrid; Tybell, Thomas [Department of Electronics and Telecommunications, NTNU, Trondheim (Norway); Holmestad, Randi [Department of Physics, NTNU, Trondheim (Norway)

2016-10-15

Thresholds for beam damage have been assessed for La{sub 0.7}Sr{sub 0.3}MnO{sub 3} and SrTiO{sub 3} as a function of electron probe current and exposure time at 80 and 200 kV acceleration voltage. The materials were exposed to an intense electron probe by aberration corrected scanning transmission electron microscopy (STEM) with simultaneous acquisition of electron energy loss spectroscopy (EELS) data. Electron beam damage was identified by changes of the core loss fine structure after quantification by a refined and improved model based approach. At 200 kV acceleration voltage, damage in SrTiO{sub 3} was identified by changes both in the EEL fine structure and by contrast changes in the STEM images. However, the changes in the STEM image contrast as introduced by minor damage can be difficult to detect under several common experimental conditions. No damage was observed in SrTiO{sub 3} at 80 kV acceleration voltage, independent of probe current and exposure time. In La{sub 0.7}Sr{sub 0.3}MnO{sub 3}, beam damage was observed at both 80 and 200 kV acceleration voltages. This damage was observed by large changes in the EEL fine structure, but not by any detectable changes in the STEM images. The typical method to validate if damage has been introduced during acquisitions is to compare STEM images prior to and after spectroscopy. Quantifications in this work show that this method possibly can result in misinterpretation of beam damage as changes of material properties. - Highlights: • We studied the effects of a TEM electron beam on a perovskite heterostructure. • Using an improved ELNES quantification method, subtle changes could be observed. • On LSMO changes were observed in the ELNES, but none in the STEM-HAADF. • For STO changes were observed in both ELNES and STEM-HAADF. • This shows beam damage can be misinterpreted as material properties.

Can one observe by μ SR the transition from uncorrelated to correlated spin fluctuations? Example: Nd1.4Ce0.2Sr0.4CuO4-δ

International Nuclear Information System (INIS)

Pinkpank, M.; Amato, A.; Gygax, F.N.; Schenck, A.; Henggeler, W.; Fischer, P.

1997-01-01

μSR-measurements in ZF and LF on Nd 1.4 Ce 0.2 Sr 0.4 CuO 4-δ show a sharp increase of the depolarisation rate (λ) below ∼ 2K. This increase can be explained by the transition from uncorrelated to correlated spin fluctuations, which is in agreement with results obtained by neutron scattering

Buffer, backfill and closure process report for the safety assessment SR-Site

International Nuclear Information System (INIS)

Sellin, Patrik

2010-11-01

This report gives an account of how processes in buffer, deposition tunnel backfill and the closure important for the long-term evolution of a KBS-3 repository for spent nuclear fuel, will be documented in the safety assessment SR-Site

Buffer, backfill and closure process report for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

Sellin, Patrik (ed.)

2010-11-15

This report gives an account of how processes in buffer, deposition tunnel backfill and the closure important for the long-term evolution of a KBS-3 repository for spent nuclear fuel, will be documented in the safety assessment SR-Site

Experiences with the determination of Sr-89 and Sr-90 using fast methods; Erfahrungen bei der Bestimmung von {sup 89}Sr und {sup 90}Sr mittels Schnellmethoden

Energy Technology Data Exchange (ETDEWEB)

Kowalik, C.; Fueger, J. [Thueringer Landesanstalt fuer Umwelt und Geologie, Jena (Germany). Landesmessstelle fuer Umweltradioaktivaet

2014-01-20

Quick methods of the measurement of {sup 89}Sr and {sup 90}Sr have a great importance in the supervision of the environmental radioactivity. It is necessary to receive in short time dependable analytical data to be able to carry out suitable assessments or to give recommendations. The aim of the investigations was to be guaranteed the demands for these methods (test preparation, measurement and evaluation). The use of the solid phase extraction by means of commercial Sr Resin trademark columns (4.4' (5')-Di-tert-butylcyclohexanol-18-kronen-6-aether) (Triskem) to the radiochemical separation of the Sr isotopes was suitable. The measurements occurred to the FHT 770 T12 - Multi Low Level Alpha/Beta Sample Counter (Thermo Scientific). The results contain the summary activities of all available Sr isotopes, as for example {sup 89}Sr and {sup 90}Sr. The calculations of the single activities occur about the mathematical algorithm of the linear development on the basis of the works of G. Kanisch. The first results show, this method is suitable for the analysis of {sup 89}Sr and {sup 90}Sr and is used therefore in future in Thuringia.

Novel approaches for 90Sr analyses in contaminated environmental samples

International Nuclear Information System (INIS)

Kavasi, N.; Sahoot, S.K.; Area, H.; Aono, T.

2016-01-01

Radioactive strontium isotopes are generated with high cumulative fission yield (5-6 %) during thermal neutron fission in a nuclear reactor. The physical half-life of 89 Sr (50.52 d) is short but that of 90 Sr (28.8 y) is long enough to generate radioecological repercussions. 90 Sr has a long-lasting biological half-life (∼18 y) in the human body, due to its chemical similarity to calcium the importance of 90 Sr analysis is emphasized in case of a nuclear disaster. The world-wide spread of 90 Sr, as a background, is derived from the global atmospheric fallout contributed by large-scale atmospheric nuclear weapons tests conducted from 1945. In case of local contamination, nuclear accidents are not the only source of 90 Sr isotope, misconducted underground nuclear weapon tests; improper handling of by-products of nuclear weapon production or normal operation of nuclear facilities (e.g. reprocessing plants) can be taken into account

Electronic properties and surface reactivity of SrO-terminated SrTiO3 and SrO-terminated iron-doped SrTiO3.

Science.gov (United States)

Staykov, Aleksandar; Tellez, Helena; Druce, John; Wu, Ji; Ishihara, Tatsumi; Kilner, John

2018-01-01

Surface reactivity and near-surface electronic properties of SrO-terminated SrTiO 3 and iron doped SrTiO 3 were studied with first principle methods. We have investigated the density of states (DOS) of bulk SrTiO 3 and compared it to DOS of iron-doped SrTiO 3 with different oxidation states of iron corresponding to varying oxygen vacancy content within the bulk material. The obtained bulk DOS was compared to near-surface DOS, i.e. surface states, for both SrO-terminated surface of SrTiO 3 and iron-doped SrTiO 3 . Electron density plots and electron density distribution through the entire slab models were investigated in order to understand the origin of surface electrons that can participate in oxygen reduction reaction. Furthermore, we have compared oxygen reduction reactions at elevated temperatures for SrO surfaces with and without oxygen vacancies. Our calculations demonstrate that the conduction band, which is formed mainly by the d-states of Ti, and Fe-induced states within the band gap of SrTiO 3 , are accessible only on TiO 2 terminated SrTiO 3 surface while the SrO-terminated surface introduces a tunneling barrier for the electrons populating the conductance band. First principle molecular dynamics demonstrated that at elevated temperatures the surface oxygen vacancies are essential for the oxygen reduction reaction.

Investigating the hydrological significance of stalagmite geochemistry (Mg, Sr) using Sr isotope and particulate element records across the Late Glacial-to-Holocene transition

Science.gov (United States)

Belli, R.; Borsato, A.; Frisia, S.; Drysdale, R.; Maas, R.; Greig, A.

2017-02-01

The trace element and Sr isotope records in two coeval stalagmites characterized by different growth rates and flow regimes at Savi cave (Grotta Savi, NE Italy) reveal different sources and incorporation mechanisms for Mg and Sr. Mg is sourced primarily from dissolved cave host rock while particulate Mg derived from soil plays a subordinate role. The presence of particulate-borne Mg is inferred from the co-variation of Mg and particle-associated elements (Th, Al and Mn) which are preferentially concentrated in open columnar calcite layers. Variation in Mg concentrations corrected for particle-influenced components, the Mgc parameter, is controlled by water-rock interaction, with higher and lower Mgc during dry and wet phases, respectively. This is thought to reflect incongruent dissolution of Mg-rich phases. Correction of Sr concentrations for contributions from airborne exogenic Sr, based on 87Sr/86Sr ratios, yields the bedrock-only contribution (Src). Src variation in stalagmite calcite is influenced by speleothem growth rate and by variation of the calcite-water Sr partitioning in wet and dry phases, and only to a minor extent by incongruent dissolution of Mg-rich phases. Concentration profiles for Mgc and Srcg (corrected for growth rate effects) show inverse correlations and are inferred to show hydrological significance which is captured in a hydrological index, HI. We suggest HI provides robust information on water-rock interaction related to hydrological changes and can be utilized in both wet and semi-arid environments, provided the corrections for soil Mg and exogenic Sr can be applied with confidence. Application of the HI index allows correction of Grotta Savi oxygen isotope data, to yield a δ18Oc time series that shows when changes in moisture sources and atmospheric reorganization, or changes in moisture amount, were significant. This is especially evident during the Younger Dryas (YD). The Savi record supports the concept of a two-phase YD, marked by

Mineralogy and geochemistry of rocks and fracture fillings from Forsmark and Oskarshamn: Compilation of data for SR-Can

Energy Technology Data Exchange (ETDEWEB)

Drake, Henrik; Sandstroem, Bjoern [Isochron GeoConsulting HB, Goeteborg (Sweden); Tullborg, Eva-Lena [Terralogica AB, Graabo (Sweden)

2006-11-15

This report is a compilation of the so far available data for the safety assessment SR-Can carried out by SKB. The data consists of mineralogy, geochemistry, porosity, density and redox properties for both dominating rock types and fracture fillings at the Forsmark and Oskarshamn candidate areas. In addition to the compilation of existing information, the aim has been to identify missing data and to clarify some conception of e.g. deformation zones. The objective of the report is to present the available data requested for the modelling of the chemical stability of the two sites. The report includes no interpretation of the data.

Assessment of 137Cs and 90Sr Fluxes in the Barents Sea

Science.gov (United States)

Matishov, Gennady; Usiagina, Irina; Kasatkina, Nadezhda; Ilin, Gennadii

2014-05-01

On the basis of published and own data the annual balance of radionuclide income/outcome was assessed for 137Cs and 90Sr in the Barents Sea for the period from 1950s to the presnt. The scheme of the isotope balance calculation in the Barents Sea included the following processes:atmospheric fallout; river run-off; liquid radioactive wastes releases, income from the Norwegian and the White Seas; outflow to the adjacent areas through the Novaya Zemlya straits and the transects Svalbard-Franz Josef Land and Franz Josef Land-Novaya Zemlya; radioactive decay. According to the multiyear dynamics, the inflow of 137Cs and 90Sr to the Barents Sea was significantly preconditioned by currents from the Norwegian Sea. Three peaks of 137Cs and 90Sr isotope concentrations were registered for the surface waters on the western border of the Barents Sea. The first one was observed in the mid-1960s and was conditioned by testing of nuclear weapons. The increase of isotope concentrations in 1975 and 1980 was preconditioned by the discharge of atomic waste by the Sellafield nuclear reprocessing plant. Nowadays, after the sewage disposal plant was built, the annual discharge of nuclear waste from Sellafield plant is low. The Norwegian Sea was a major source of 137Cs and 90Sr isotope income into the Barents Sea for the period of 1960-2014. Currently, the transborder transfer of 90Sr and 137Cs from the Norwegian Sea into the Barents Sea constitutes about 99% of income for each element. Atmospheric precipitation had a major impact in the 1950-1960s after the testing of the nuclear weapons, and in 1986 after the accident at Chernobyl Nuclear Power Station. In 1963, the atmospheric precipitation of 137Cs reached 1050 TBq; and that of 90Sr, 630 TBq. In 1986, a significant amount of 137Cs inflow (up to 1010 TBq/year) was registered. The 137Cs isotope income exceeded the 90Sr income in the 1960s-1980s, and equal amounts penetrated into the Barents Sea from the Norwegian Sea in the 1990s. Before

Results of field studies on 90SR and stable SR soil-to-plant transfer

International Nuclear Information System (INIS)

Gerzabek, M.H.; Artner, C.; Horak, O.; Mueck, K.

1992-01-01

In 1987 and 1988 at 35 sites plants ready to harvest and the corresponding soils (0 - 20 cm) were collected for 90 Sr and stable strontium analyses. Sample preparation and measurement led to a detection limit of 0.008 Bq 90 Sr kg -1 . The 90 Sr-contamination of Austrian soils ranged from 396 to 1998 Bq m -2 . Known from literature the contribution of the Chernobyl fallout amounted to app. 25 % of the total contamination. Stable strontium contents of the soils were between 6 and 62.5 mg kg -1 . Bariumtriethanolamine extracted 17.7 to 62.3 % of the total stable Sr in soil. 90 Sr-concentrations in cereal grains ranged from 0.03 to 0.67 Bq kg -1 (fresh wight) for maize and barley, respectively. The values for other foodstuff were between 0.15 (white cabbage) and 0.91 Bq kg -1 (spinach). Stable strontium contents were between 0.079 mg kg -1 (maize) and 72.5 mg kg -1 (celery shoot). The following mean 90 Sr soil-to-plant transfer factors for cereal grains were obtained: 0.010 (maize), 0.097 (rye), 0.049 (wheat), 0.095 (barley). Transfer factors for straw were up to 50 times higher (maize). The transfer of 90 Sr into vegetables and potatoes reached the same order of magnitude compared to the cereals. In all cases soil-to-plant transfer of stable Sr was clearly lower up to 60 % of the respective values for 90 Sr. Thus natural stable strontium is less plant available than 90 Sr. The influence of soil parameters on the 90 Sr transfer into plants was examinated by correlation analyses. Increasing exchangeable calcium contents of the soils resulted in a significant reduction of Sr soil-to-barley straw transfer. (authors)

Review of SKB's interim report of SR-Can: SKI's and SSI's evaluation of SKB's up-dated methodology for safety assessment

Energy Technology Data Exchange (ETDEWEB)

Dverstorp, Bjoern; Moberg, Leif; Wiebert, Anders; Xu Shulan [Swedish Radiation Protection Authority, Stockholm (Sweden); Stroemberg, Bo; Kautsky, Fritz; Lilja, Christina; Simic, Eva; Sundstroem, Benny; Toverud, Oeivind [Swedish Nuclear Power Inspectorate, Stockholm (Sweden)

2005-07-01

This report presents the findings of a review of the Swedish Nuclear Fuel and Waste Management Co.'s (SKB) interim report of the safety assessment SR-Can (SKB TR 04-11), conducted by the Swedish Radiation Protection Authority (SSI) and the Swedish Nuclear Power Inspectorate (SKI). SKB's interim report describes and exemplifies the safety assessment methodology that SKB plans to use in the oncoming licence applications for an encapsulation plant and a final repository for spent nuclear fuel. The authorities' review takes into account the findings of an international peer review of SKB's interim report. The authorities conclude that SKB has improved its safety assessment methodology in several aspects compared to earlier safety reports. Among other things the authorities commend SKB for giving a comprehensive account of relevant regulations and guidance, and for the systematic approach to identification and documentation of features, events and processes that need to be considered in the safety assessment. However, the authorities also conclude that important parts of SKB's method need to be further developed before they are mature enough to be used as a basis for a license application. The authorities' overall assessment is summarised in chapter 8 of this report.

Review of SR 97

International Nuclear Information System (INIS)

Voss, C.I.

2000-01-01

generate fluxes, travel paths and travel times, it is dangerous to use unproven probability distributions as the basis for assessment of hydrogeologic impact on repository safety. There may be serious doubt that the fluxes and path values derived from SR 97 ground-water modeling are appropriate for determining near-field release and far-field transport because they are based on poorly founded probabilistic assumptions, on weak hydrogeologic structural models of the sites, and on static boundary conditions, despite the expectation of strong climate change effects. In this light, it is interesting that SR 97 directly used very little of the extensive ground-water modeling results, funneling all of the considerations and complexities for each site into a few selected values for use in release, transport, and dose calculations. It can be argued that, if these few values are all that are needed for performance assessment, they can be equally well determined by simple hydrogeologic scoping calculations for a site, rather than through the type of extensive effort applied in SR 97

Effect of Wood Aging on Wine Mineral Composition and 87Sr/86Sr Isotopic Ratio.

Science.gov (United States)

Kaya, Ayse D; Bruno de Sousa, Raúl; Curvelo-Garcia, António S; Ricardo-da-Silva, Jorge M; Catarino, Sofia

2017-06-14

The evolution of mineral composition and wine strontium isotopic ratio 87 Sr/ 86 Sr (Sr IR) during wood aging were investigated. A red wine was aged in stainless steel tanks with French oak staves (Quercus sessiliflora Salisb.), with three industrial scale replicates. Sampling was carried out after 30, 60, and 90 days of aging, and the wines were evaluated in terms of general analysis, phenolic composition, total polysaccharides, multielement composition, and Sr IR. Li, Be, Mg, Al, Sc, Ti, V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Sb, Cs, Ba, Pr, Nd, Sm, Eu, Dy, Ho, Er, Yb, Lu, Tl, and Pb elements and 87 Sr/ 86 Sr were determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and Na, K, Ca, and Fe by flame atomic absorption spectrometry (FAAS). Two-way ANOVA was applied to assess wood aging and time effect on Sr IR and mineral composition. Wood aging resulted in significantly higher concentrations of Mg, V, Co, Ni, and Sr. At the end of the aging period, wine exhibited statistically identical Sr IR compared to control. Study suggests that wood aging does not affect 87 Sr/ 86 Sr, not precluding the use of this parameter for wine traceability purposes.

Activity ratios of {sup 137}Cs, {sup 90}Sr and {sup 239+240}Pu in environmental samples

Energy Technology Data Exchange (ETDEWEB)

Bossew, P. [European Commission - DG Joint Research Centre, Institute for Environment and Sustainability (IES), I-21020 Ispra (Vatican City State, Holy See,) (Italy)], E-mail: peter.bossew@jrc.it; Lettner, H. [Institute of Physics and Biophysics, University of Salzburg, Hellbrunner Strasse 34, A-5020 Salzburg (Austria)], E-mail: herbert.lettner@sbg.ac.at; Hubmer, A.; Erlinger, C.; Gastberger, M. [Institute of Physics and Biophysics, University of Salzburg, Hellbrunner Strasse 34, A-5020 Salzburg (Austria)

2007-09-15

Both global and Chernobyl fallout have resulted in environmental contamination with radionuclides such as {sup 137}Cs, {sup 90}Sr and {sup 239+240}Pu. In environmental samples, {sup 137}Cs and {sup 239+240}Pu can be divided into the contributions of either source, if also the isotopes {sup 134}Cs and {sup 238}Pu are measurable, based on the known isotopic ratios in global and Chernobyl fallout. No analogous method is available for {sup 90}Sr. The activity ratios of Sr to Cs and Pu, respectively, are known for the actual fallout mainly from air filter measurements; but due to the high mobility of Sr in the environment, compared to Cs and Pu, these ratios generally do not hold for the inventory many years after deposition. In this paper we suggest a method to identify the mean contributions of global and Chernobyl fallout to total Sr in soil, sediment and cryoconite samples from Alpine and pre-Alpine regions of Austria, based on a statistical evaluation of Sr/Cs/Pu radionuclide activity ratios. Results are given for Sr:Cs, Sr:Pu and Cs:Pu ratios. Comparison with fallout data shows a strong depletion of Sr against Cs and Pu.

Strontium (Sr) separation from seawater using titanate adsorbents: Effects of seawater matrix ions on Sr sorption behavior

Science.gov (United States)

Ryu, Jungho; Hong, Hye-jin; Ryu, Taegong; Park, In-Su

2017-04-01

Strontium (Sr) which has many industrial applications such as ferrite magnet, ceramic, and fire works exists in seawater with the concentration of approximately 7 mg/L. In previous report estimating economic potential on recovery of various elements from seawater in terms of their commercial values and concentrations in seawater, Sr locates upper than approximate break-even line, which implies Sr recovery from seawater can be potentially profitable. Recently, Sr separation from seawater has received great attention in the environmental aspect after Fukushima Nuclear Power Plant (NPP) accident which released much amount of radioactive Sr and Cs. Accordingly, the efficient separation of radioactive elements released to seawater has become critical as an important technological need as well as their removal from radioactive wastes. So far, it has been introduced to separate Sr from aqueous media by various methods including solvent extraction, adsorption by solid materials, and ion exchange. Among them, the adsorption technique using solid adsorbents is of great interest for selectively separating Sr from seawater with respect to low concentration level of Sr. In this study, we synthesized titanate nanotube (TiNT) by simple hydrothermal reaction, characterized its physicochemical properties, and systematically evaluated Sr sorption behavior under various reaction conditions corresponding to seawater environment. The synthesized TiNT exhibited the fibril-type nanotube structure with high specific surface area of 260 m2/g. The adsorption of Sr on TiNT rapidly occurred following pseudo-second-order kinetic model, and was in good agreement with Langmuir isotherm model, indicating maximum adsorption capacity of 97 mg/g. Based on Sr uptake and Na release with stoichiometric balance, sorption mechanism of Sr on TiNT was found to be ion-exchange between Na in TiNT lattice and Sr in solution phase, which was also confirmed by XRD and Raman analysis. Among competitive ions, Ca

Assessing ambition of nationally determined contributions

International Nuclear Information System (INIS)

Höhne, Niklas

2015-01-01

A key for a successful new international climate agreement by December 2015 will be the collective assessment of ambition of individual proposals by countries on how and how much to reduce their greenhouse gas emissions. We conclude that there is nothing right or wrong in choosing one or several of these approaches to assess the level of ambition of contributions. An approach using several of many methods described can take into account the difference in national circumstances.

Thermodynamic modeling of the Sr-Co-Fe-O system

DEFF Research Database (Denmark)

Zhang, Wei Wei; Povoden-Karadeniz, Erwin; Chen, Ming

2016-01-01

This paper reviews and assesses phase equilibria and thermodynamic properties of phases in the Sr-Co-Fe-O system, with a focus on oxides, especially the SrCo1 - xFexO3 - δ perovskite. In our work, the SrCo1 - xFexO3 - δ perovskite was modeled with a three-sublattice model, where the three...... sublattices correspond to the A, B and oxygen sites in an ABO3 perovskite, respectively. A number of other important ternary oxide phases in Sr-Co-O and Sr-Co-Fe-O were also considered. Available thermodynamic and phase diagram data were carefully assessed. A thermodynamic description of Sr-Co-O was derived...

Bedrock Kd data and uncertainty assessment for application in SR-Site geosphere transport calculations

International Nuclear Information System (INIS)

Crawford, James

2010-12-01

The safety assessment SR-Site is undertaken to assess the safety of a potential geologic repository for spent nuclear fuel at the Forsmark and Laxemar sites. The present report is one of several reports that form the data input to SR-Site and contains a compilation of recommended K d data (i.e. linear partitioning coefficients) for safety assessment modelling of geosphere radionuclide transport. The data are derived for rock types and groundwater compositions distinctive of the site investigation areas at Forsmark and Laxemar. Data have been derived for all elements and redox states considered of importance for far-field dose estimates as described in /SKB 2010d/. The K d data are given in the form of lognormal distributions characterised by a mean (μ) and standard deviation (σ). Upper and lower limits for the uncertainty range of the recommended data are defined by the 2.5% and 97.5% percentiles of the empirical data sets. The best estimate K d value for use in deterministic calculations is given as the median of the K d distribution

Isotope ratio 87Sr/86Sr in limestones from Bambui group, Brazil (MG)

International Nuclear Information System (INIS)

Kawashita, K.; Mizusaki, A.M.P.; Kiang, C.H.

1987-01-01

The Sr composition of ancient seawater can be estimated from the analysis of carbonate rocks and, in some cases, used to estimate the age of the analyzed carbonate. The normalized 87Sr/86Sr ratios in calcium carbonate fractions from 14 core samples in the Bambui Group near Montalvania, MG, were found to range between .7077 and .7280. The higher values are attributable to Sr isotopic exchange between silicate and carbonate phases during diagenesis. The ratio of .7077 obtained in two pure calcium carbonate samples is here suggested as the best aproximation for the 87Sr/86Sr value for the Bambui sea. This ratio is compatible with an age of about 700 Ma., estimated from the published 87Sr/86Sr curve of Veizer and others, an age in accordance with Quadros recent (1987, in preparation) identification of marine acritarchs from the latest Precambrian (Vendian). (author) [pt

A new approach to assess the effects of Sr and Bi interaction in ADC12 Al–Si die casting alloy

International Nuclear Information System (INIS)

Farahany, Saeed; Ourdjini, Ali; Abu Bakar, Tuty Asma; Idris, Mohd Hasbullah

2014-01-01

Highlights: • Interactive effect between Bi and Sr has been invesitigated comprehensively. • Sequence of addition did not affect thermal and microscopical characteristics. • A new map has been established to assess the final microstructure of castings. - Abstract: In the present paper, the possible interaction between bismuth and strontium in ADC12 die casting alloy was investigated comprehensively by using in situ thermal analysis technique. The characteristic temperatures including nucleation, minimum and growth temperatures of eutectic Al–Si were also analyzed. The results show that with Bi present in the Al–Si alloy melt the efficiency of Sr in modifying the eutectic Si is reduced. A threshold Sr/Bi ratio of at least 0.5 is required for a fully modified Si structure to form. A new map based on the characteristic temperatures, Sr/Bi ratio and microstructure, was established to assess the microstructure of fully solidified Al–Si castings

A new approach to assess the effects of Sr and Bi interaction in ADC12 Al–Si die casting alloy

Energy Technology Data Exchange (ETDEWEB)

Farahany, Saeed, E-mail: saeedfarahany@gmail.com; Ourdjini, Ali; Abu Bakar, Tuty Asma; Idris, Mohd Hasbullah

2014-01-10

Highlights: • Interactive effect between Bi and Sr has been invesitigated comprehensively. • Sequence of addition did not affect thermal and microscopical characteristics. • A new map has been established to assess the final microstructure of castings. - Abstract: In the present paper, the possible interaction between bismuth and strontium in ADC12 die casting alloy was investigated comprehensively by using in situ thermal analysis technique. The characteristic temperatures including nucleation, minimum and growth temperatures of eutectic Al–Si were also analyzed. The results show that with Bi present in the Al–Si alloy melt the efficiency of Sr in modifying the eutectic Si is reduced. A threshold Sr/Bi ratio of at least 0.5 is required for a fully modified Si structure to form. A new map based on the characteristic temperatures, Sr/Bi ratio and microstructure, was established to assess the microstructure of fully solidified Al–Si castings.

T-H-M couplings in rock. Overview of results of importance to the SR-Can safety assessment

International Nuclear Information System (INIS)

Hoekmark, Harald; Faelth, Billy; Wallroth, Thomas

2006-09-01

This report deals with THM processes in rock hosting a KBS-nuclear waste repository. The issues addressed are mechanically and thermo-mechanically induced changes of the hydraulic conditions in the near-field and in the far-field, and the risk of stress-induced failure, spalling, in the walls of deposition holes. These changes are examined for the construction and operational phases, the initial temperate period and a subsequent glacial cycle. The report was compiled to be used as reference and background for corresponding parts of the safety report SR-Can. The near-field is analyzed using thermo-mechanical DEC models. There are a number of models for each of the three sites Forsmark, Simpevarp and Laxemar. Parameter values of intact rock and rock mass mechanical and thermo-mechanical properties were obtained from the site descriptive models. Layout data, i.e. the number of canisters, the geometry of the repository openings, the tunnel spacing and the canister spacing are in accordance with rules and guidelines given in general design- and layout documents. Heat generation data, i.e. the initial canister power and the canister power decay are in accordance with data given in the SR-Can main report. The effects of changes in nearfield stresses during the different phases of the repository's lifetime are evaluated by comparing numerically obtained stresses and deformations on a number of explicitly modelled near-field fractures with empirical and theoretical stress-transmissivity laws and with empirically based slip-transmissivity estimates. For the near-field it is concluded that substantial transmissivity increases are found only very close to the repository openings. Bounding estimates, judged to be valid for the entire load sequence, are made of the extent and magnitude of the hydraulic disturbance. At distances larger than about 1.5 m from the tunnel periphery, transmissivity increases are concluded to be too small and unsystematic to be of any concern. The

T-H-M couplings in rock. Overview of results of importance to the SR-Can safety assessment

Energy Technology Data Exchange (ETDEWEB)

Hoekmark, Harald; Faelth, Billy [Clay Technology AB, Lund (Sweden); Wallroth, Thomas [BERGAB, Goeteborg (Sweden)

2006-09-15

This report deals with THM processes in rock hosting a KBS-nuclear waste repository. The issues addressed are mechanically and thermo-mechanically induced changes of the hydraulic conditions in the near-field and in the far-field, and the risk of stress-induced failure, spalling, in the walls of deposition holes. These changes are examined for the construction and operational phases, the initial temperate period and a subsequent glacial cycle. The report was compiled to be used as reference and background for corresponding parts of the safety report SR-Can. The near-field is analyzed using thermo-mechanical DEC models. There are a number of models for each of the three sites Forsmark, Simpevarp and Laxemar. Parameter values of intact rock and rock mass mechanical and thermo-mechanical properties were obtained from the site descriptive models. Layout data, i.e. the number of canisters, the geometry of the repository openings, the tunnel spacing and the canister spacing are in accordance with rules and guidelines given in general design- and layout documents. Heat generation data, i.e. the initial canister power and the canister power decay are in accordance with data given in the SR-Can main report. The effects of changes in nearfield stresses during the different phases of the repository's lifetime are evaluated by comparing numerically obtained stresses and deformations on a number of explicitly modelled near-field fractures with empirical and theoretical stress-transmissivity laws and with empirically based slip-transmissivity estimates. For the near-field it is concluded that substantial transmissivity increases are found only very close to the repository openings. Bounding estimates, judged to be valid for the entire load sequence, are made of the extent and magnitude of the hydraulic disturbance. At distances larger than about 1.5 m from the tunnel periphery, transmissivity increases are concluded to be too small and unsystematic to be of any concern. The

Accessible switching of electronic defect type in SrTi O3 via biaxial strain

Science.gov (United States)

Chi, Yen-Ting; Youssef, Mostafa; Sun, Lixin; Van Vliet, Krystyn J.; Yildiz, Bilge

2018-05-01

Elastic strain is used widely to alter the mobility of free electronic carriers in semiconductors, but a predictive relationship between elastic lattice strain and the extent of charge localization of electronic defects is still underdeveloped. Here we considered SrTi O3 , a prototypical perovskite as a model functional oxide for thin film electronic devices and nonvolatile memories. We assessed the effects of biaxial strain on the stability of electronic defects at finite temperature by combining density functional theory (DFT) and quasiharmonic approximation (QHA) calculations. We constructed a predominance diagram for free electrons and small electron polarons in this material, as a function of biaxial strain and temperature. We found that biaxial tensile strain in SrTi O3 can stabilize the small polaron, leading to a thermally activated and slower electronic transport, consistent with prior experimental observations on SrTi O3 and distinct from our prior theoretical assessment of the response of SrTi O3 to hydrostatic stress. These findings also resolved apparent conflicts between prior atomistic simulations and conductivity experiments for biaxially strained SrTi O3 thin films. Our computational approach can be extended to other functional oxides, and for the case of SrTi O3 our findings provide concrete guidance for conditions under which strain engineering can shift the electronic defect type and concentration to modulate electronic transport in thin films.

Structural and compositional characterization of synthetic (Ca,Sr)-tremolite and (Ca,Sr)-diopside solid solutions

Science.gov (United States)

Gottschalk, M.; Najorka, J.; Andrut, M.

Tremolite (CaxSr1-x)2Mg5[Si8O22/(OH)2] and diopside (CaxSr1-x)Mg[Si2O6] solid solutions have been synthesized hydrothermally in equilibrium with a 1 molar (Ca,Sr)Cl2 aqueous solution at 750°C and 200 MPa. The solid run products have been investigated by optical, electron scanning and high resolution transmission electron microscopy, electron microprobe, X-ray-powder diffraction and Fourier-transform infrared spectroscopy. The synthesized (Ca,Sr)-tremolites are up to 2000 µm long and 30 µm wide, the (Ca,Sr)-diopsides are up to 150 µm long and 20 µm wide. In most runs the tremolites and diopsides are well ordered and chain multiplicity faults are rare. Nearly pure Sr-tremolite (tr0.02Sr-tr0.98) and Sr-diopside (di0.01Sr-di0.99) have been synthesized. A continuous solid solution series, i.e. complete substitution of Sr2+ for Ca2+ on M4-sites exists for (Ca,Sr)-tremolite. Total substitution of Sr2+ for Ca2+ on M2-sites can be assumed for (Ca,Sr)-diopsides. For (Ca,Sr)-tremolites the lattice parameters a, b and β are linear functions of composition and increase with Sr-content whereas c is constant. For the diopside series all 4 lattice parameters are a linear function of composition; a, b, c increase and β decreases with rising Sr-content. The unit cell volume for tremolite increases 3.47% from 906.68 Å3 for tremolite to 938.21 Å3 for Sr-tremolite. For diopside the unit cell volume increases 4.87 % from 439.91 Å3 for diopside to 461.30 Å3 for Sr-diopside. The observed splitting of the OH stretching band in tremolite is caused by different configurations of the next nearest neighbors (multi mode behavior). Resolved single bands can be attributed to the following configurations on the M4-sites: SrSr, SrCa, CaCa and CaMg. The peak positions of these 4 absorption bands are a linear function of composition. They are shifted to lower wavenumbers with increasing Sr-content. No absorption band due to the SrMg configuration on the M4-site is observed. This indicates

Handling of future human actions in the safety assessment SR-Site

International Nuclear Information System (INIS)

2010-12-01

authorities in their review of SR-Can /Dverstorp and Stroemberg 2008/ maintain that the state, rather than SKB, is expected to be responsible for the supervision and monitoring of the repository after sealing. Man is dependent on, and influences, the environment in which he lives. After the repository has been closed, future generations should be able to utilise the repository site according to their needs without jeopardising their health. In the case of a final repository of the KBS-3 type, there are, however, inevitably examples of activities that, if carried out carelessly or without knowledge of the repository, could result in exposure to radiotoxic elements from the spent fuel. Therefore, there is an international consensus that future human activities shall be considered in safety assessments of deep geological repositories. Based on generally accepted principles and the Swedish Radiation Safety Authority's, SSM's, regulations SSM FS 2008:21 and SSM FS 2008:37, the future human actions considered in this part of the safety assessment are restricted to global pollution and actions that: - are carried out after the sealing of the repository, - take place at or close to the repository site, - are unintentional, i.e. are carried out when the location of the repository is unknown, its purpose forgotten or the consequences of the action are unknown, - impair the safety functions of the repository's barriers. However, in line with SSM's general guidance /SSM 2008a/, future human actions and their impact on the repository are evaluated separately, and are not included in the main scenario reference evolution or in the risk summation

Handling of future human actions in the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

2010-12-15

authorities in their review of SR-Can /Dverstorp and Stroemberg 2008/ maintain that the state, rather than SKB, is expected to be responsible for the supervision and monitoring of the repository after sealing. Man is dependent on, and influences, the environment in which he lives. After the repository has been closed, future generations should be able to utilise the repository site according to their needs without jeopardising their health. In the case of a final repository of the KBS-3 type, there are, however, inevitably examples of activities that, if carried out carelessly or without knowledge of the repository, could result in exposure to radiotoxic elements from the spent fuel. Therefore, there is an international consensus that future human activities shall be considered in safety assessments of deep geological repositories. Based on generally accepted principles and the Swedish Radiation Safety Authority's, SSM's, regulations SSM FS 2008:21 and SSM FS 2008:37, the future human actions considered in this part of the safety assessment are restricted to global pollution and actions that: - are carried out after the sealing of the repository, - take place at or close to the repository site, - are unintentional, i.e. are carried out when the location of the repository is unknown, its purpose forgotten or the consequences of the action are unknown, - impair the safety functions of the repository's barriers. However, in line with SSM's general guidance /SSM 2008a/, future human actions and their impact on the repository are evaluated separately, and are not included in the main scenario reference evolution or in the risk summation

Thermodynamic modeling of the Sr-Co-Fe-O system

DEFF Research Database (Denmark)

Zhang, Wei Wei; Povoden-Karadeniz, Erwin; Chen, Ming

2016-01-01

This paper reviews and assesses phase equilibria and thermodynamic properties of phases in the Sr-Co-Fe-O system, with a focus on oxides, especially the SrCo1 - xFexO3 - δ perovskite. In our work, the SrCo1 - xFexO3 - δ perovskite was modeled with a three-sublattice model, where the three...... sublattices correspond to the A, B and oxygen sites in an ABO3 perovskite, respectively. A number of other important ternary oxide phases in Sr-Co-O and Sr-Co-Fe-O were also considered. Available thermodynamic and phase diagram data were carefully assessed. A thermodynamic description of Sr-Co-O was derived...... using the CALPHAD approach and was further extrapolated to that of Sr-Co-Fe-O. The thermodynamic database of Sr-Co-Fe-O established in this work allows for calculating phase diagrams, thermodynamic properties, cation distribution and defect chemistry properties, and therefore enables material...

Sr-Pb-Nd isotopic evidence that both MORB and OIB sources contribute to oceanic island arc magmas in Fiji

International Nuclear Information System (INIS)

Gill, J.B.

1984-01-01

Twenty-eight new Pb, 20 Sr, and 9 Nd isotopic compositions are presented for 32 rocks and one galena from Fiji and the South Fiji (back-arc) Basin. The Fijian rocks range in age from 35 to 143 Nd/ 144 Nd and low 206 Pb/ 204 Pb). Nearly constant 207 Pb/ 204 Pb, and an OIB source component lying within the conventional Sr-Nd-Pb mantle array. In later calc-alkaline and shoshonitic series rocks, these same trace element and isotopic ratios are more like those of OIB. The change was not accompanied by an increase in 207 Pb/ 204 Pb or Cs/K, indeed, 207 Pb/ 204 Pb is closer to the mantle array in these later series. Consequently, the change indicates a greater contribution from OIB sources, rather than from recycled ocean crust. These interpretations require that both MORB and OIB sources coexist in the uppermost mantle above subducted lithosphere. (orig./WB)

Determination of 90Sr by liquid scintillation counting

International Nuclear Information System (INIS)

Cerchetti, Maria L.; Aghazarian, V.P.

2006-01-01

99m Tc, the result of the radioactive decay of 99 Mo, is one of the most applied radioisotopes in nuclear medicine and is used in nuclear medicine as a radiopharmaceutical product. It is important to ensure 99 Mo quality in order to fit the 99m Tc quality specifications. The main objective was to obtain a technique for 90 Sr determination in 99 Mo and environmental samples. The purification of 90 Sr is performed by extraction chromatography where crown-ether resin (Sr-Spec, Eichrom) was used. The measurement of the 90 Sr activity is performed by Liquid Scintillation Counting (LSC) using the double windows method. This method permits the 90 Sr determination without waiting until radiochemical equilibrium 90 Sr / 90 Y has been reached. The recovery factor was determined by gamma spectrometry with 85 Sr, and by gravimetry with stable strontium carrier solution. The minimum detectable activity was 0,05 Bq. The recovery factor was the major contribution in the total uncertainty. (author)

137Cs and 90Sr IN lizards of Semipalatinsk test site.

Science.gov (United States)

Panitskiy, А V; Lukashenko, S N; Kadyrova, N Zh

2017-01-01

The paper provides research results of 137 Cs and 90 Sr radionuclides concentrations in bodies of Lacertidae family lizards, inhabiting different parts of Semipalatinsk Test Site, and the parameters of these radionuclides' transfer into lizards' bodies. It shows that high activity concentration of radionuclides in lizards' bodies can be noticed if they live directly at locally contaminated areas. Since the distance from contaminated spots exceeds home range of the studied animals, no increased values of radionuclides' activity were found in the animal bodies. At some individual radioactively contaminated spots, very high activity concentrations of 90 Sr radionuclide up to 7.8 × 10 5  Bq kg -1 were found in lizards. So under certain conditions, lizards can significantly contribute to radionuclides redistribution in the natural environment. Mean concentration ratios (CR) of radionuclides were as follows: 137 Cs-6.2 × 10 -3 , 90 Sr-1.1 × 10 -2 . Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of Sr-90 in water samples: precision and accuracy

International Nuclear Information System (INIS)

Nisti, Marcelo B.; Saueia, Cátia H.R.; Castilho, Bruna; Mazzilli, Barbara P.

2017-01-01

The study of artificial radionuclides dispersion into the environment is very important to control the nuclear waste discharges, nuclear accidents and nuclear weapons testing. The accidents in Fukushima Daiichi Nuclear Power Plant and Chernobyl Nuclear Power Plant, released several radionuclides in the environment by aerial deposition and liquid discharge, with various level of radioactivity. The 90 Sr was one of the elements released into the environment. The 90 Sr is produced by nuclear fission with a physical half-life of 28.79 years with decay energy of 0.546 MeV. The aims of this study are to evaluate the precision and accuracy of three methodologies for the determination of 90 Sr in water samples: Cerenkov, LSC direct method and with radiochemical separation. The performance of the methodologies was evaluated by using two scintillation counters (Quantulus and Hidex). The parameters Minimum Detectable Activity (MDA) and Figure Of Merit (FOM) were determined for each method, the precision and accuracy were checked using 90 Sr standard solutions. (author)

Peer assessment of individual contributions to a group project: Student perceptions

International Nuclear Information System (INIS)

Kench, Peter L.; Field, Nikki; Agudera, Maila; Gill, Margo

2009-01-01

Group work has many benefits for a student's professional development but it is difficult to determine the individual contributions to the group assessment tasks. Peer assessment of an individual's contribution to group work can be used to encourage student participation. It is important that the method of peer assessment is fair and that the students' submissions be treated confidentially. A model for peer assessment of individual contributions to the group assessment is described. Students who did not participate adequately in the group were penalised resulting in a reduced individual grade. Perceptions of the peer assessment method are reported for students enrolled (n = 169) in the subject 'Medical Radiations Project'. The questionnaire showed a positive student response towards the peer assessment model.

Regional and interspecific variation in Sr, Ca, and Sr/Ca ratios in avian eggshells from the USA.

Science.gov (United States)

Mora, Miguel A; Brattin, Bryan; Baxter, Catherine; Rivers, James W

2011-08-01

To examine regional variation in strontium (Sr), which at high concentrations may reduce eggshell quality, increase egg breakage and reproductive failure, we analyzed Sr, and calcium (Ca) concentrations and Sr/Ca ratios in eggshells from 20 avian species from California, Texas, Idaho, Kansas, and Michigan. In addition, we included data previously reported from Arizona to expand the regional comparisons and to better establish patterns of Sr, and Sr/Ca ratios in bird species across the United States. We found Sr concentrations varied significantly among regions, among species, and among foraging guilds; this variability is strongly influenced by the Sr/Ca ratios in surface water from locations close to the region where the eggshells were collected. Sr concentrations and Sr/Ca ratios were significantly higher in bird eggshells from the Volta wildlife region in the San Joaquin Valley, California and in various locales from Arizona. Sr concentrations and Sr/Ca ratios in bird eggshells from other locations in the USA were lower than those detected in these two regions. Among foraging guilds, invertivores had the highest Sr concentrations and Sr/Ca ratios and carnivores had the lowest. In general, the Sr/Ca ratio increased strongly with increasing Sr concentrations (R(2) = 0.99, P eggshells suggesting that these values could be determined from Sr/Ca ratios in water. Eggshell thickness was poorly correlated with Sr (R(2) = 0.03) but had a significant and positive correlation with Ca and was more properly correlated by a quadratic equation (R(2) = 0.50, Thickness = 2.13 - 0.02Ca - 3.07 * 10(-5)Ca(2)). Our study provides further evidence that Sr accumulates significantly in the avian eggshell, in some regions at concentrations which could be of concern for potential negative effects on reproduction. We suggest that when assessing the effects of metals on avian reproduction in regions with high Sr deposits in rock and soil, Sr concentrations in the eggshell also should be

Assessment of Sr-90 in water samples: precision and accuracy

Energy Technology Data Exchange (ETDEWEB)

Nisti, Marcelo B.; Saueia, Cátia H.R.; Castilho, Bruna; Mazzilli, Barbara P., E-mail: mbnisti@ipen.br, E-mail: chsaueia@ipen.br, E-mail: bcastilho@ipen.br, E-mail: mazzilli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2017-11-01

The study of artificial radionuclides dispersion into the environment is very important to control the nuclear waste discharges, nuclear accidents and nuclear weapons testing. The accidents in Fukushima Daiichi Nuclear Power Plant and Chernobyl Nuclear Power Plant, released several radionuclides in the environment by aerial deposition and liquid discharge, with various level of radioactivity. The {sup 90}Sr was one of the elements released into the environment. The {sup 90}Sr is produced by nuclear fission with a physical half-life of 28.79 years with decay energy of 0.546 MeV. The aims of this study are to evaluate the precision and accuracy of three methodologies for the determination of {sup 90}Sr in water samples: Cerenkov, LSC direct method and with radiochemical separation. The performance of the methodologies was evaluated by using two scintillation counters (Quantulus and Hidex). The parameters Minimum Detectable Activity (MDA) and Figure Of Merit (FOM) were determined for each method, the precision and accuracy were checked using {sup 90}Sr standard solutions. (author)

The 87Sr/86Sr aquatic isoscape of the Danube catchment from the source to the mouth as tool for studying fish migrations

Science.gov (United States)

Zitek, Andreas; Tchaikovsky, Anastassiya; Irrgeher, Johanna; Waidbacher, Herwig; Prohaska, Thomas

2014-05-01

Isoscapes - spatially distributed isotope patterns across landscapes - are increasingly used as important basis for ecological studies. The natural variation of the isotopic abundances in a studied area bears the potential to be used as natural tracer for studying e.g. migrations of animals or prey-predator relations. The 87Sr/86Sr ratio is one important tracer, since it is known to provide a direct relation of biological samples to geologically distinct regions, as Sr isotopes are incorporated into living tissues as a proxy for calcium and taken up from the environment without any significant fractionation. Although until now the focus has been mainly set on terrestrial systems, maps for aquatic systems are increasingly being established. Here we present the first 87Sr/86Sr aquatic isoscape of the Danube catchment, the second largest river catchment in Europe, from near its source starting at river km 2581 in Germany down to its mouth to river km 107 in Romania. The total length of the river Danube is 2780 km draining a catchment area 801 463 km2 (10 % of the European continent). The major purpose of this study was to assess the potential of the 87Sr/86Sr isotope ratio to be used as tool for studying fish migrations at different scales in the entire Danube catchment. Within the Joint Danube Research 3 (JDS 3), the biggest scientific multi-disciplinary river expedition of the World in 2013 aiming at the assessment of the ecological status and degree of human alterations along the river Danube, water samples were taken at 68 pre-defined sites along the course of the river Danube including the major tributaries as a basis to create the so called 'Isoscape of the Danube catchment'. The determination of 87Sr/86Sr isotope ratio in river water was performed by multicollector-sector field-inductively coupled plasma-mass spectrometry (MC-SF-ICP-MS). The JDS 3 data were combined with existing data from prior studies conducted within the Austrian part of the Danube catchment

Corrosion calculations report for the safety assessment SR-Site

International Nuclear Information System (INIS)

2010-12-01

This report is a compilation of the quantitative assessments of corrosion of the copper canisters in a KBS-3 repository. The calculations are part of the safety assessment SR-Site that is the long-term safety assessment to support the license application for building a final repository for spent nuclear fuel at Forsmark, Sweden. The safety assessment methodology gives the frame for the structured and documented approach to assess all conceivable corrosion processes. The quantitative assessments are done in different ways depending on the nature of the process and on the implications for the long-term safety. The starting point for the handling of the corrosion processes is the description of all known corrosion processes for copper with the current knowledge base and applied to the specific system and geology. Already at this stage some processes are excluded for further analysis, for example if the repository environment is not a sufficient prerequisite for the process to occur. The next step is to identify processes where the extent of corrosion could be bounded, e.g. by a mass balance approach. For processes where a mass balance is not limiting, the mass transport of corrodants (or corrosion products) is taken into account. A simple approach would be just to calculate the diffusive transport of corrodants through the bentonite, but generally the transport resistance for the interface between groundwater in a rock fracture intersecting the deposition hole and the bentonite buffer is more important. In SR-Site, the concept of equivalent flowrate, Q eq , is used. This assessment is done integrated with the evaluation of the geochemical and hydrogeological evolution of the repository. For most of the corrosion processes analysed, the corrosion depth is much smaller than the copper shell thickness, even for the assessment time of 10 6 years. Several processes give corrosion depths less than 100 μm, but no process give corrosion depths larger than a few millimetres

Corrosion calculations report for the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

2010-12-15

This report is a compilation of the quantitative assessments of corrosion of the copper canisters in a KBS-3 repository. The calculations are part of the safety assessment SR-Site that is the long-term safety assessment to support the license application for building a final repository for spent nuclear fuel at Forsmark, Sweden. The safety assessment methodology gives the frame for the structured and documented approach to assess all conceivable corrosion processes. The quantitative assessments are done in different ways depending on the nature of the process and on the implications for the long-term safety. The starting point for the handling of the corrosion processes is the description of all known corrosion processes for copper with the current knowledge base and applied to the specific system and geology. Already at this stage some processes are excluded for further analysis, for example if the repository environment is not a sufficient prerequisite for the process to occur. The next step is to identify processes where the extent of corrosion could be bounded, e.g. by a mass balance approach. For processes where a mass balance is not limiting, the mass transport of corrodants (or corrosion products) is taken into account. A simple approach would be just to calculate the diffusive transport of corrodants through the bentonite, but generally the transport resistance for the interface between groundwater in a rock fracture intersecting the deposition hole and the bentonite buffer is more important. In SR-Site, the concept of equivalent flowrate, Q{sub eq}, is used. This assessment is done integrated with the evaluation of the geochemical and hydrogeological evolution of the repository. For most of the corrosion processes analysed, the corrosion depth is much smaller than the copper shell thickness, even for the assessment time of 106 years. Several processes give corrosion depths less than 100 mum, but no process give corrosion depths larger than a few

Hybrid HF-DFT comparative study of SrZrO{sub 3} and SrTiO{sub 3}(001) surface properties

Energy Technology Data Exchange (ETDEWEB)

Evarestov, R.A.; Bandura, A.V.; Alexandrov, V.E. [Department of Quantum Chemistry, St. Petersburg State University, 26 Universitetskii Prospekt, Stary Petergof, 198504 St. Petersburg (Russian Federation)

2006-10-15

Hybrid HF-DFT LCAO simulations of SrZrO{sub 3} and SrTiO{sub 3}(001) surface properties are performed in a single-slab model framework. The SrZrO{sub 3}(001) surface was studied by an ab initio method for the first time. Three slab models with different surface terminations including up to 8 atomic planes were used for calculation of the various surface characteristics (surface energies, atomic charges, density of electronic states). The dependence of the results on the chosen model and on the kind of d-element is analyzed. The dissimilarity in the surface oxygen atom contributions to the total density of states of two crystals is attributed to the more ionic nature of Zr-O bonds compared to Ti-O bonds. It is found that in the case of SrZrO{sub 3} the electronic density is biased towards the SrO-terminated surface and this surface should be more basic in nature than the SrO surface of SrTiO{sub 3} crystal. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Surface modeling and chemical solution deposition of SrO(SrTiO3)n Ruddlesden-Popper phases

International Nuclear Information System (INIS)

Zschornak, M.; Gemming, S.; Gutmann, E.; Weissbach, T.; Stoecker, H.; Leisegang, T.; Riedl, T.; Traenkner, M.; Gemming, T.; Meyer, D.C.

2010-01-01

Strontium titanate (STO) is a preferred substrate material for functional oxide growth, whose surface properties can be adjusted through the presence of Ruddlesden-Popper (RP) phases. Here, density functional theory (DFT) is used to model the (1 0 0) and (0 0 1) surfaces of SrO(SrTiO 3 ) n RP phases. Relaxed surface structures, electronic properties and stability relations have been determined. In contrast to pure STO, the near-surface SrO-OSr stacking fault can be employed to control surface roughness by adjusting SrO and TiO 2 surface rumpling, to stabilize SrO termination in an SrO-rich surrounding or to increase the band gap in the case of TiO 2 termination. RP thin films have been epitaxially grown on (0 0 1) STO substrates by chemical solution deposition. In agreement with DFT results, the fraction of particular RP phases n = 1-3 changes with varying heating rate and molar ratio Sr:Ti. This is discussed in terms of bulk formation energy.

Assessing the complexity of interventions within systematic reviews: development, content and use of a new tool (iCAT_SR

Directory of Open Access Journals (Sweden)

Simon Lewin

2017-04-01

pathway between intervention and outcome. Dimensions 1–6 are considered ‘core’ dimensions. Dimensions 7–10 are optional and may not be useful for all interventions. Conclusions The iCAT_SR tool facilitates more in-depth, systematic assessment of the complexity of interventions in systematic reviews and can assist in undertaking reviews and interpreting review findings. Further testing of the tool is now needed.

The adsorption of Cs+, Sr2+ and Ni2+ on bitumen: a mechanistic model

International Nuclear Information System (INIS)

Loon, L.R. Van; Kopajtic, Z.

1991-01-01

The adsorption of radionuclides on the waste matrix is a positive effect and contributes to the retardation of released radionuclides migrating to the geo-and biosphere. For the safety assessment studies, it is important to know whether or not radionuclides do adsorb on the waste matrix. In the present work the adsorption of 134 Cs + , 85 Sr 2+ and 63 Ni 2+ on bitumen was studied as a function of the pH and ionic strength of the equilibrium solution. Bitumen emulsions with well defined surfaces were used. The surface of bitumen is negatively charged due to the deprotonation of weak acid carboxyl groups at the interface. The functional group density amounts to 1.37.10 18 groups/m 2 and their deprotonation behaviour can be well described by the 'Ionizable Surface Group' model. Cs + , Sr 2+ and Ni 2+ adsorb on the surface by three different processes, i.e. ion exchange, outer sphere complexation and inner sphere surface complexation respectively. The adsorption depends on the pH and the ionic strength of the contact solution. Under near field conditions, Cs + and Sr 2+ do not adsorb on the bitumen due to the competition with Na + , K + and Ca 2+ present in the cement pore water in contact with the bitumen. Ni 2+ adsorption can also be neglected because the formation of neutral and anionic hydroxo complexes in solution competes strongly with the adsorption reaction. Other hydrolysable radionuclides of interest are expected to behave similarly to Ni 2+ . The main conclusion of the study is that the adsorption of radionuclides under near field conditions is expected to be very low. Consequently, this process need not to be considered in safety assessment studies. (author) figs., tabs., 30 refs

Bedrock K{sub d} data and uncertainty assessment for application in SR-Site geosphere transport calculations

Energy Technology Data Exchange (ETDEWEB)

Crawford, James (Kemakta Konsult AB, Stockholm (Sweden))

2010-12-15

The safety assessment SR-Site is undertaken to assess the safety of a potential geologic repository for spent nuclear fuel at the Forsmark and Laxemar sites. The present report is one of several reports that form the data input to SR-Site and contains a compilation of recommended K{sub d} data (i.e. linear partitioning coefficients) for safety assessment modelling of geosphere radionuclide transport. The data are derived for rock types and groundwater compositions distinctive of the site investigation areas at Forsmark and Laxemar. Data have been derived for all elements and redox states considered of importance for far-field dose estimates as described in /SKB 2010d/. The K{sub d} data are given in the form of lognormal distributions characterised by a mean (mu) and standard deviation (sigma). Upper and lower limits for the uncertainty range of the recommended data are defined by the 2.5% and 97.5% percentiles of the empirical data sets. The best estimate K{sub d} value for use in deterministic calculations is given as the median of the K{sub d} distribution

Cancer risk due to Cs-137 and Sr-90 dietary intake after the Chernobyl accident

International Nuclear Information System (INIS)

Toader, M.; Vasilache, R.A.

1997-01-01

The most important radionuclides carried by the radioactive plume over Romania were I 131 , Cs 134 , Cs 137 and Sr 90 . As in many other countries, in the first days, I 131 had the main contribution to the irradiation dose released to the population. After its decay, and the decay of the other short-lived radionuclides, Cs 137 and Sr 90 remained the most important contaminants. The principal route of intake for these two radionuclides is considered to be the ingestion of contaminated foods. Assessments of radiation doses to people living in the Bucharest area have utilized data obtained from measurement of Cs 137 and Sr 90 content in dietary intake samples for a number of subjects of different ages and sexes. This paper summarizes the results of some of our measurements performed since April 1986 until March 1995. 7 refs, 8 figs

87Sr/86Sr isotopes in grapes of different cultivars: A geochemical tool for geographic traceability of agriculture products.

Science.gov (United States)

Tescione, Ines; Marchionni, Sara; Casalini, Martina; Vignozzi, Nadia; Mattei, Massimo; Conticelli, Sandro

2018-08-30

87 Sr/ 86 Sr was determined on fresh red and white grapes, soils and rocks from three selected vineyards to verify the isotopic relationships between the fruit of the vine and geologic substrata of vineyards. 87 Sr/ 86 Sr were determined on sampled grapes of four different harvest years and different grape varieties, on bioavailable fraction of soils, on whole soils, and on bedrocks from the geo-pedological substratum of the vineyards. The vineyards chosen for the experimental works belong to an organic farming winery and thus cultivation procedures were strictly controlled. Grapes were sampled during the harvests of four different but consecutive years with 87 Sr/ 86 Sr that does not change reflecting the values of the soil bioavailable fraction. No variations among grapes from different vine cultivars were observed. A strict isotope relationship with soil bio-available fraction was observed. These findings demonstrate the reliability of 87 Sr/ 86 Sr, even at a very small scale, for food products geographic origin assessment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Rb-Sr ages and initial 87Sr/86Sr ratios of late paleozoic granitic rocks from northern Chile

International Nuclear Information System (INIS)

Shibata, Ken; Ishihara, Shunso; Ulriksen, C.E.

1984-01-01

Rb-Sr whole-rock isochron ages were determined on three suites of so-called Paleozoic granitic rocks from northern coastal Chile. The granitic rocks from the Valparaiso and Ci Funcho areas are dated as 296.3 +- 5.4 Ma and 262.2 +- 4.6 Ma, respectively, which are in accord with geologically estimated age. The rocks from the Chanaral area is dated as 212.8 +- 8.6 Ma, which is correlated close to the Triassic-Jurassic boundary age. A K-Ar age of 196 +- 6 Ma was obtained on biotite in granite from Esmeralda between Ci Funcho and Chanaral. These age results demonstrate that no Precambrian plutonism occurred in the studied area, and that so-called Paleozoic granitic rocks in the Ci Funcho-Chanaral area are divided into Permian and early Mesozoic in age. Initial 87 Sr/ 86 Sr ratios of the ilmenite-series granitic rocks from the coastal region are 0.70641 (Valparaiso), 0.70635 (Ci Funcho) and 0.70455 (Chanaral). These relatively low ratios deny substantial crustal contribution to the granitoids. The initial ratios of magnetite-series granitoids from porphyry- and manto-type mineralized areas (Chiquicamata, El Salvador and Tocopilla) are as low as 0.70344 to 0.70464. (author)

Optimization of 90Sr/89Sr measurements

Directory of Open Access Journals (Sweden)

Legarda F.

2012-04-01

Full Text Available One of the key points in the double measurement method for the measurement of both, 89Sr and 90Sr, by using a proportional counter is the choice of the times at which the measurements should be done. In this paper, the formulae to calculate the 89Sr and 90Sr detection limits in conditions of radioactive equilibrium between 90Y and 90Sr are derived, and an analysis of them as a function of the time between the two measurements is done. The choice for the time of the second measurement is going to depend on the desired quality of the results to be obtained.

High Sr/Y rocks are not all adakites!

Science.gov (United States)

Moyen, Jean-François

2010-05-01

The name of "adakite" is used to describe a far too large group of rocks, whose sole common feature is high Sr/Y and La/Yb ratios. Defining adakites only by this criterion is misleading, as the definition of this group of rocks does include many other criteria, including major elements. In itself, high (or commonly moderate!) Sr/Y ratios can be achieved via different processes: melting of a high Sr/Y (and La/Yb) source; deep melting, with abundant residual garnet; fractional crystallization or AFC; or interactions of felsic melts with the mantle, causing selective enrichment in LREE and Sr over HREE. A database of the compositions of "adakitic" rocks - including "high silica" and "low silica" adakites, "continental" adakites and Archaean adakites—was assembled. Geochemical modeling of the potential processes is used to interpret it, and reveals that (1) the genesis of high-silica adakites requires high pressure evolution (be it by melting or fractionation), in equilibrium with large amounts of garnet; (2) low-silica adakites are explained by garnet-present melting of an adakite-metasomatized mantle, i.e at depths greater than 2.5 GPa; (3) "Continental" adakites is a term encompassing a huge range of rocks, with a corresponding diversity of petrogenetic processes, and most of them are different from both low- and high- silica adakites; in fact in many cases it is a complete misnomer and the rocks studied are high-K calc-alkaline granitoids or even S-type granites; (4) Archaean adakites show a bimodal composition range, with some very high Sr/Y examples (similar to part of the TTG suite) reflecting deep melting (> 2.0 GPa) of a basaltic source with a relatively high Sr/Y, while lower Sr/Y rocks formed by shallower (1.0 GPa) melting of similar sources. Comparison with the Archaean TTG suite highlights the heterogeneity of the TTGs, whose composition spreads the whole combined range of HSA and Archaean adakites, pointing to a diversity of sources and processes

Comparative study of potentially J{sub eff} = 0 ground state iridium(V) in SrLaNiIrO{sub 6}, SrLaMgIrO{sub 6}, and SrLaZnIrO{sub 6}

Energy Technology Data Exchange (ETDEWEB)

Wolff, Klaus K.; Agrestini, Stefano; Tjeng, Liu Hao [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); Tanaka, Arata [Department of Quantum Matter, AdSM, Hiroshima University, Higashi-Hiroshima (Japan); Jansen, Martin [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); Max Planck Institute for Solid State Research, Stuttgart (Germany)

2017-12-13

A series of polycrystalline double perovskites SrLaBIrO{sub 6} (B = Ni, Mg, Zn) containing Ir{sup 5+} (5d{sup 4}) was synthesized by solid state reactions, and structural, magnetic and electronic properties were investigated. The isotypic fully ordered double perovskites crystallize in space group P2{sub 1}/n and show semiconducting behavior with estimated bandgaps of approximately 0.2 eV for SrLaNiIrO{sub 6} and SrLaZnIrO{sub 6}, and 0.4 eV for SrLaMgIrO{sub 6}. SrLaNiIrO{sub 6} is an antiferromagnet with a Neel temperature of 74 K (μ{sub eff} = 3.3 μ{sub B}, θ{sub W} = -90 K), whereas SrLaMgIrO{sub 6} and SrLaZnIrO{sub 6} are weakly paramagnetic. All title compounds exhibit a temperature-independent contribution to the measured magnetic susceptibility, which supports the notion for a van-Vleck-type response originating from the Ir{sup 5+} (5d{sup 4}, J{sub eff} = 0) ions. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Assessing Covariation of Holocene Monsoon Intensity and Local Moisture Conditions in Eastern and Southwestern Amazon Basin Using Speleothem δ18O and 87Sr/86Sr Values

Science.gov (United States)

Ward, B. M.; Wong, C. I.; Novello, V. F.; Silva, L.; McGee, D.; Cheng, H.; Wang, X.; Edwards, R. L.; Cruz, F. W., Sr.; Santos, R. V.

2017-12-01

δ18O records from South America offer insight into past variability of the South American Monsoon System (SAMS). Potential, however, for understanding local moisture conditions is limited as precipitation δ18O is strongly influenced by regional climate dynamics. Here we create Holocene speleothem 87Sr/86Sr records at 200-yr resolution using TIMS methods in the Center for Isotope Geochemistry at Boston College to complement existing Holocene δ18O speleothem records and investigate local moisture conditions above caves located in the eastern Amazon Basin (PAR - 4°S, 55°W) and southwestern Brazil (JAR - 21°S, 56°W). Speleothem 87Sr/86Sr variability is interpreted to reflect differences in the extent of water-rock interaction due to differences in infiltration rates under wet and dry conditions. Drier conditions promote longer residence time, enhanced water-rock interaction, and greater evolution of dripwater 87Sr/86Sr values from an initial isotopic signature acquired from the soil to the signature of the cave host rock. PAR speleothem 87Sr/86Sr values range from 0.71024 to 0.71067 and are bracketed by soil (0.71710 to 0.70956) and bedrock (0.70852 to 0.70899) values. JAR speleothem 87Sr/86Sr values range from 0.71216 to 0.71539 and are greater than bedrock values (0.70825 to 0.71219), although some speleothem values exceed the single analysis conducted of the soil isotopic composition (0.71473). JAR speleothem 87Sr/86Sr values increase from the early to mid Holocene, consistent with increase in local moisture availability associated with intensification of the SAMS suggested by decreasing δ18O values in many records from the region. Speleothem 87Sr/86Sr values at JAR decrease from the mid to late Holocene, consistent with an increase in δ18O values at PAR that suggest a decline in monsoon intensity. 87Sr/86Sr variability at JAR, however, is positively correlated with the δ18O record. Preliminary 87Sr/86Sr results from PAR are only broadly consistent with

Implementing systematic review techniques in chemical risk assessment: Challenges, opportunities and recommendations.

Science.gov (United States)

Whaley, Paul; Halsall, Crispin; Ågerstrand, Marlene; Aiassa, Elisa; Benford, Diane; Bilotta, Gary; Coggon, David; Collins, Chris; Dempsey, Ciara; Duarte-Davidson, Raquel; FitzGerald, Rex; Galay-Burgos, Malyka; Gee, David; Hoffmann, Sebastian; Lam, Juleen; Lasserson, Toby; Levy, Len; Lipworth, Steven; Ross, Sarah Mackenzie; Martin, Olwenn; Meads, Catherine; Meyer-Baron, Monika; Miller, James; Pease, Camilla; Rooney, Andrew; Sapiets, Alison; Stewart, Gavin; Taylor, David

2016-01-01

Systematic review (SR) is a rigorous, protocol-driven approach designed to minimise error and bias when summarising the body of research evidence relevant to a specific scientific question. Taking as a comparator the use of SR in synthesising research in healthcare, we argue that SR methods could also pave the way for a "step change" in the transparency, objectivity and communication of chemical risk assessments (CRA) in Europe and elsewhere. We suggest that current controversies around the safety of certain chemicals are partly due to limitations in current CRA procedures which have contributed to ambiguity about the health risks posed by these substances. We present an overview of how SR methods can be applied to the assessment of risks from chemicals, and indicate how challenges in adapting SR methods from healthcare research to the CRA context might be overcome. Regarding the latter, we report the outcomes from a workshop exploring how to increase uptake of SR methods, attended by experts representing a wide range of fields related to chemical toxicology, risk analysis and SR. Priorities which were identified include: the conduct of CRA-focused prototype SRs; the development of a recognised standard of reporting and conduct for SRs in toxicology and CRA; and establishing a network to facilitate research, communication and training in SR methods. We see this paper as a milestone in the creation of a research climate that fosters communication between experts in CRA and SR and facilitates wider uptake of SR methods into CRA. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Geochemical tracing of As pollution in the Orbiel Valley (southern France): 87Sr/86Sr as a tracer of the anthropogenic arsenic in surface and groundwater.

Science.gov (United States)

Khaska, Mahmoud; Le Gal La Salle, Corinnne; Lancelot, Joël; Verdoux, Patrick; Boutin, René

2014-05-01

The environmental impacts of arsenic mining activities and their effects on ecosystem and human health are observed in many stream waters and groundwater. The aim of this study is to identify the origin of As content in a mining environment using Sr isotopes. At the Salsigne gold mine, before the closure in 2004, high arsenic content has been observed in surface water and groundwater in the Orbiel valley. At the site, immobilization of As, in As rich leachate, is carried out by adding CaO. High contrast in 87Sr/86Sr between Arsenic rich minerals associated with Variscan metamorphic rocks (0.714888-0.718835), together with rich As waste water (0.713463-715477), and the CaO (0.707593) allows as to trace the origin of anthropogenic As. In 2012, Orbiel stream waters were sampled monthly upstream and downstream from the ancient ore processing site and once after an important rainy event (117mm). The upstream valley samples showed low and relatively constant As content with natural regional background of 3.6 and 5.6 μg/L. The rainy event induced only a slight increase in the As content up to 6.3 μg/L. High 87Sr/86Sr ratios suggested an influence of radiogenic Sr issued from the Variscan metamorphic basement. Downstream from the area, the As content was at least10 time as high. In the wet season, stream water As content clearly increased to 13.9-24 μg/L, reaching 120.5 μg/L during the rainy event. Associated 87Sr/86Sr ratio showed to be less radiogenic (0.712276-0.714002). The anti correlation observed between As and 87Sr/86Sr suggest that As issued from a natural origin is characterised by a high 87Sr/86Sr compared to As derived from the CaO treatement used on site and characterized by a low 87Sr/86Sr ratio. During the dry season, increase in As content was observed reaching 110 μg/L. These highlights the contribution of alluvial groundwater to base flow, probably associated with As reach leachate from the site. Contribution from the alluvial aquifer is confirmed by

Hydrologic controls on radiogenic Sr in meltwater from an alpine glacier system: Athabasca Glacier, Canada

International Nuclear Information System (INIS)

Arendt, C.A.; Stevenson, E.I.; Aciego, S.M.

2016-01-01

Filtered subglacial meltwater samples were collected daily during the onset of melt (May) and peak melt (July) over the 2011 melt season at the Athabasca Glacier (Alberta, Canada) and analyzed for strontium-87/strontium-86 ("8"7Sr/"8"6Sr) isotopic composition to infer the evolution of subglacial weathering processes. Both the underlying bedrock composition and subglacial water–rock interaction time are the primary influences on meltwater "8"7Sr/"8"6Sr. The Athabasca Glacier is situated atop Middle Cambrian carbonate bedrock that also contains silicate minerals. The length of time that subglacial meltwater interacts with the underlying bedrock and substrate is a predominant determining factor in solute concentration. Over the course of the melt season, increasing trends in Ca/K and Ca/Mg correspond to overall decreasing trends in "8"7Sr/"8"6Sr, which indicate a shift in weathering processes from the presence of silicate weathering to primarily carbonate weathering. Early in the melt season, rates of carbonate dissolution slow as meltwater approaches saturation with respect to calcite and dolomite, corresponding to an increase in silicate weathering that includes Sr-rich silicate minerals, and an increase in meltwater "8"7Sr/"8"6Sr. However, carbonate minerals are preferentially weathered in unsaturated waters. During the warmest part of a melt season the discharged meltwater is under saturated, causing an increase in carbonate weathering and a decrease in the radiogenic Sr signal. Likewise, larger fraction contributions of meltwater from glacial ice corresponds to lower "8"7Sr/"8"6Sr values, as the meltwater has lower water–rock interaction times in the subglacial system. These results indicate that although weathering of Sr-containing silicate minerals occurs in carbonate dominated glaciated terrains, the continual contribution of new meltwater permits the carbonate weathering signal to dominate. - Highlights: • Glacial meltwater "8"7Sr/"8"6Sr used to

Contributions of a disulfide bond and a reduced cysteine side chain to the intrinsic activity of the high-density lipoprotein receptor SR-BI.

Science.gov (United States)

Yu, Miao; Lau, Thomas Y; Carr, Steven A; Krieger, Monty

2012-12-18

The high-density lipoprotein (HDL) receptor scavenger receptor class B, type I (SR-BI), binds HDL and mediates selective cholesteryl ester uptake. SR-BI's structure and mechanism are poorly understood. We used mass spectrometry to assign the two disulfide bonds in SR-BI that connect cysteines within the conserved Cys(321)-Pro(322)-Cys(323) (CPC) motif and connect Cys(280) to Cys(334). We used site-specific mutagenesis to evaluate the contributions of the CPC motif and the side chain of extracellular Cys(384) to HDL binding and lipid uptake. The effects of CPC mutations on activity were context-dependent. Full wild-type (WT) activity required Pro(322) and Cys(323) only when Cys(321) was present. Reduced intrinsic activities were observed for CXC and CPX, but not XXC, XPX, or XXX mutants (X ≠ WT residue). Apparently, a free thiol side chain at position 321 that cannot form an intra-CPC disulfide bond with Cys(323) is deleterious, perhaps because of aberrant disulfide bond formation. Pro(322) may stabilize an otherwise strained CPC disulfide bond, thus supporting WT activity, but this disulfide bond is not absolutely required for normal activity. C(384)X (X = S, T, L, Y, G, or A) mutants exhibited altered activities that varied with the side chain's size: larger side chains phenocopied WT SR-BI treated with its thiosemicarbazone inhibitor BLT-1 (enhanced binding, weakened uptake); smaller side chains produced almost inverse effects (increased uptake:binding ratio). C(384)X mutants were BLT-1-resistant, supporting the proposal that Cys(384)'s thiol interacts with BLT-1. We discuss the implications of our findings on the functions of the extracellular loop cysteines in SR-BI and compare our results to those presented by other laboratories.

Observation of Isotope Ratios (δ2H, δ18O, 87Sr/86Sr) of Tap Water in Urban Environments

Science.gov (United States)

Mancuso, C. J.; Tipple, B. J.; Ehleringer, J. R.

2014-12-01

Urban environments are centers for rapidly growing populations. In order to meet the culinary water needs of these areas, municipal water departments use water from multiple locations and/or sources, often piped differentially to different locations within a municipality. This practice creates isotopically distinct locations within an urban area and therefore provides insight to urban water management practices. In our study we selected urban locations in the Salt Lake Valley, UT (SLV) and San Francisco Bay Area, CA (SFB) where we hypothesized geographically distinct water isotopic ratio differences existed. Within the SLV, municipal waters come from the same mountainous region, but are derived from different geologically distinct watersheds. In contrast, SFB waters are derived from regionally distinct water sources. We hypothesized that the isotope ratios of tap waters would differ based upon known municipal sources. To test this, tap water samples were collected throughout the urban regions in SLV and SFB and analyzed for δ2H, δ18O and 87Sr/86Sr isotope ratios. Seasonal collections were also made to assess if isotope ratios differed throughout the year. Within SLV and SFB, different regions were characterized by distinct paired δ18O and 87Sr/86Sr values. These different realms also agreed with known differences in municipal water supplies within the general geographic region. Waters from different cities within Marin County showed isotopic differences, consistent with water derived from different local reservoirs. Seasonal variation was observed in paired δ18O and 87Sr/86Sr values of tap water for some locations within SLV and SFB, indicating management decisions to shift from one water source to another depending on demand and available resources. Our study revealed that the δ18O and 87Sr/86Sr values of tap waters in an urban region can exhibit significant differences despite close spatial proximity if districts differ in their use of local versus

The inverse F-BAR domain protein srGAP2 acts through srGAP3 to modulate neuronal differentiation and neurite outgrowth of mouse neuroblastoma cells.

Directory of Open Access Journals (Sweden)

Yue Ma

Full Text Available The inverse F-BAR (IF-BAR domain proteins srGAP1, srGAP2 and srGAP3 are implicated in neuronal development and may be linked to mental retardation, schizophrenia and seizure. A partially overlapping expression pattern and highly similar protein structures indicate a functional redundancy of srGAPs in neuronal development. Our previous study suggests that srGAP3 negatively regulates neuronal differentiation in a Rac1-dependent manner in mouse Neuro2a cells. Here we show that exogenously expressed srGAP1 and srGAP2 are sufficient to inhibit valporic acid (VPA-induced neurite initiation and growth in the mouse Neuro2a cells. While ectopic- or over-expression of RhoGAP-defective mutants, srGAP1(R542A and srGAP2(R527A exert a visible inhibitory effect on neuronal differentiation. Unexpectedly, knockdown of endogenous srGAP2 fails to facilitate the neuronal differentiation induced by VPA, but promotes neurite outgrowth of differentiated cells. All three IF-BAR domains from srGAP1-3 can induce filopodia formation in Neuro2a, but the isolated IF-BAR domain from srGAP2, not from srGAP1 and srGAP3, can promote VPA-induced neurite initiation and neuronal differentiation. We identify biochemical and functional interactions of the three srGAPs family members. We propose that srGAP3-Rac1 signaling may be required for the effect of srGAP1 and srGAP2 on attenuating neuronal differentiation. Furthermore, inhibition of Slit-Robo interaction can phenocopy a loss-of-function of srGAP3, indicating that srGAP3 may be dedicated to the Slit-Robo pathway. Our results demonstrate the interplay between srGAP1, srGAP2 and srGAP3 regulates neuronal differentiation and neurite outgrowth. These findings may provide us new insights into the possible roles of srGAPs in neuronal development and a potential mechanism for neurodevelopmental diseases.

Coral Sr-U Thermometry

Science.gov (United States)

DeCarlo, T. M.; Gaetani, G. A.; Cohen, A. L.; Foster, G. L.; Alpert, A.; Stewart, J.

2016-12-01

Coral skeletons archive the past two millennia of climate variability in the oceans with unrivaled temporal resolution. However, extracting accurate temperature information from coral skeletons is confounded by "vital effects", which often override the temperature dependence of geochemical proxies. Here, we present a new approach to coral paleothermometry based on results of abiogenic precipitation experiments interpreted within a framework provided by a quantitative model of the coral biomineralization process. We conducted laboratory experiments to test the temperature and carbonate chemistry controls on abiogenic partitioning of Sr/Ca and U/Ca between aragonite and seawater, and we modeled the sensitivity of skeletal composition to processes occurring at the site of calcification. The model predicts that temperature can be accurately reconstructed from coral skeleton by combining Sr/Ca and U/Ca ratios into a new proxy, Sr-U. We tested the model predictions with measured Sr/Ca and U/Ca ratios of fourteen Porites sp. corals collected from the tropical Pacific Ocean and the Red Sea, with a subset also analyzed using the boron isotope (δ11B) pH proxy. Observed relationships among Sr/Ca, U/Ca, and δ11B agree with model predictions, indicating that the model accounts for the key features of the coral biomineralization process. We calibrated Sr-U to instrumental temperature records and found that it captures 93% of mean annual variability (26-30 °C) and predicts temperature within 0.5 °C (1 σ). Conversely, Sr/Ca alone has an error of prediction of 1 °C and often diverges from observed temperature by 3 °C or more. Many of the problems afflicting Sr/Ca - including offsets among neighboring corals and decouplings from temperature during coral stress events - are reconciled by Sr-U. By accounting for the influence of the coral biomineralization process, the Sr-U thermometer may offer significantly improved reliability for reconstructing ocean temperatures from coral

Stable and Radiogenic Sr Isotopes in Barite - Clues on the Links Between Weathering, Climate and the C Cycle

Science.gov (United States)

Paytan, A.; Eisenhauer, A.; Wallmann, K. J. G.; Griffith, E. M.; Ridgwell, A.

2017-12-01

The radiogenic Sr-isotopic signature (87Sr/86Sr) of seawater fluctuates primarily in response to changes in the inputs of Sr from weathering and hydrothermal activity, which have distinct 87Sr/86Sr values. Changes in the isotopic ratio of the weathered terrain also contribute to observed changes in 87Sr/86Sr. The stable Sr-isotope ratios in seawater (mass dependent isotopic fractionation; δ88/86Sr) fluctuate primarily in response to the rate of calcium carbonate (CaCO3) accumulation at the seafloor. Together the radiogenic and stable Sr can constrain the coupling between weathering and sedimentation and shed light on the relation between weathering, CaCO3 deposition, the global carbon (C) cycle and climate. Reconstruction of the coupled stable and radiogenic Sr seawater curves over the past 35 Ma of Earth history indicates that the location and rate of CaCO3 burial in the ocean fluctuated considerably over the past 35 Ma. Between 35 to 18 Ma a reduction in neritic CaCO3 burial and increased burial in pelagic settings is observed. The trend was reversed between 20 and 3 Ma and finally over the last 3 million years a rapid change from neritic to pelagic burial is seen. The lack of continues increase of pelagic CaCO3 burial rates suggests that silicate weathering rates have not increased monotonically over the past 35 Ma implying strong feedbacks operating in the climate system - lower atmospheric pCO2 and cooling trends (which control chemical weathering as seen from carbonate deposition in the ocean) countered the effects of uplift (which controls physical weathering) - modulating weathering rates and preventing a runaway ice-house. In addition the data suggests considerable fluctuations in seawater Sr concentrations over time. These data demonstrate how using multiple isotope proxies can help constrain interpretations of the geological record.

Cancer risk due to Cs-137 and Sr-90 dietary intake after the Chernobyl accident

Energy Technology Data Exchange (ETDEWEB)

Toader, M; Vasilache, R A [Institute of Hygiene and Public Health, Bucharest (Romania)

1997-09-01

The most important radionuclides carried by the radioactive plume over Romania were I{sup 131}, Cs{sup 134}, Cs{sup 137} and Sr{sup 90}. As in many other countries, in the first days, I{sup 131} had the main contribution to the irradiation dose released to the population. After its decay, and the decay of the other short-lived radionuclides, Cs{sup 137} and Sr{sup 90} remained the most important contaminants. The principal route of intake for these two radionuclides is considered to be the ingestion of contaminated foods. Assessments of radiation doses to people living in the Bucharest area have utilized data obtained from measurement of Cs{sup 137} and Sr{sup 90} content in dietary intake samples for a number of subjects of different ages and sexes. This paper summarizes the results of some of our measurements performed since April 1986 until March 1995. 7 refs, 8 figs.

Applicability of 87Sr/86Sr in examining return flow of irrigation water in highly agricultural watersheds in Japan

Science.gov (United States)

Yoshida, T.; Nakano, T.; Shin, K. C.; Tsuchihara, T.; Miyazu, S.; Kubota, T.

2017-12-01

-irrigated period were lower in Sr ratios and higher in Sr concentrations, suggesting an increase in contributions of the water from the shallow aquifers. Understanding the return flow of irrigation water in highly agricultural watersheds is vital for measuring any temporal changes in flow to the lower parts of the watershed, and allows for improved water management.

Large linear magnetoresistance and magnetothermopower in layered SrZnSb$_2$

OpenAIRE

Wang, Kefeng; Petrovic, C.

2016-01-01

We report the large linear magnetoresistance ($\\sim 300\\%$ in 9 T field at 2 K) and magnetothermopower in layered SrZnSb$_2$ crystal with quasi-two-dimensional Sb layers. A crossover from the semiclassical parabolic field dependent magnetoresistance to linear field dependent magnetoresistance with increasing magnetic field is observed. The magnetoresistance behavior can be described very well by combining the semiclassical cyclotron contribution and the quantum limit magnetoresistance. Magnet...

Epitaxial growth and thermodynamic stability of SrIrO3/SrTiO3 heterostructures

Science.gov (United States)

Groenendijk, D. J.; Manca, N.; Mattoni, G.; Kootstra, L.; Gariglio, S.; Huang, Y.; van Heumen, E.; Caviglia, A. D.

2016-07-01

Obtaining high-quality thin films of 5d transition metal oxides is essential to explore the exotic semimetallic and topological phases predicted to arise from the combination of strong electron correlations and spin-orbit coupling. Here, we show that the transport properties of SrIrO3 thin films, grown by pulsed laser deposition, can be optimized by considering the effect of laser-induced modification of the SrIrO3 target surface. We further demonstrate that bare SrIrO3 thin films are subject to degradation in air and are highly sensitive to lithographic processing. A crystalline SrTiO3 cap layer deposited in-situ is effective in preserving the film quality, allowing us to measure metallic transport behavior in films with thicknesses down to 4 unit cells. In addition, the SrTiO3 encapsulation enables the fabrication of devices such as Hall bars without altering the film properties, allowing precise (magneto)transport measurements on micro- and nanoscale devices.

Thermal properties of perovskite RCeO{sub 3} (R = Ba, Sr)

Energy Technology Data Exchange (ETDEWEB)

Shukla, Aarti, E-mail: aarti.phy@gmail.com [Department of Physics, Barkatullah University, Bhopal 462026 (India); Parey, Vanshree; Thakur, Rasna [Department of Physics, Barkatullah University, Bhopal 462026 (India); Srivastava, Archana [Department of Physics, Sri Sathya Sai College for women, Bhopal 462024 (India); Gaur, N.K. [Department of Physics, Barkatullah University, Bhopal 462026 (India)

2015-08-20

Highlights: • (Ba,Sr)CeO{sub 3} are high temperature protonic conductor materials. • This makes their thermal properties very interesting. • MRIM has successfully predicted the thermodynamic properties. • The computed results are in good agreement with the available experimental data. • Present results will serve as guide to experimental workers in future. - Abstract: We have investigated the bulk modulus and thermal properties of proton conducting perovskite RCeO{sub 3} (R = Ba, Sr) for the first time by incorporating the effect of lattice distortion in modified rigid ion models (MRIM). The computed bulk modulus, specific heat, thermal expansion coefficient and other thermal properties of BaCeO{sub 3} and SrCeO{sub 3} reproduce well with the available experimental data. In addition the cohesive energy (ϕ), molecular force constant (f), reststrahlen frequency (ν), Debye temperature (θ{sub D}) and Gruneisen parameter (γ) are also reported and discussed. The specific heat results can further be improved by taking into account the spin and the orbital ordering contribution in the specific heat formulae.

Using noble gases and 87Sr/86Sr to constrain heat sources and fluid evolution at the Los Azufres Geothermal Field, Mexico

Science.gov (United States)

Wen, T.; Pinti, D. L.; Castro, M. C.; Lopez Hernandez, A.; Hall, C. M.; Shouakar-Stash, O.; Sandoval-Medina, F.

2017-12-01

Geothermal wells and hot springs were sampled for noble gases' volume fraction and isotopic measurements and 87Sr/86Sr in the Los Azufres Geothermal Field (LAGF), Mexico, to understand the evolution of fluid circulation following three decades of exploitation and re-injection of used brines. The LAGF, divided into the Southern Production Zone (SPZ) and the Northern Production Zone (NPZ), is hosted in a Miocene to Pliocene andesitic volcanic complex covered by Quaternary rhyolitic-dacitic units. Air contamination corrected 3He/4He ratios (Rc) normalized to the atmospheric ratio (Ra=1.384 x 10-6), show a median value of 6.58 indicating a dominant mantle helium component. Contributions of crustal helium up to 53% and 18% are observed in NPZ and SPZ, respectively. Observations based on Rc/Ra and 87Sr/86Sr ratios points to the mixing of three magmatic sources supplying mantle helium to the LAGF: (1) a pure mantle He (Rc/Ra = 8) and Sr (87Sr/86Sr = 0.7035) source; (2) a pure mantle helium (Rc/Ra = 8) with some radiogenic Sr (87Sr/86Sr = 0.7049) source possibly resulting from Quaternary rhyolitic volcanism; and (3) a fossil mantle He component (Rc/Ra = 3.8) with some radiogenic Sr (87Sr/86Sr = 0.7038), corresponding possibly to the Miocene andesite reservoir. Intrusions within the last 50 kyrs from sources (1) and (2) are likely responsible for the addition of mantle volatiles and heat to the hydrothermal system of Los Azufres. He and Ar isotopes indicate that heat flow is transported by both convection and conduction. Atmospheric noble gas elemental ratios suggest that geothermal wells located closer to the western re-injection zone are beginning to be dominated by re-injection of used brines (injectate). The area affected by boiling in LAGF has further extended to the north and west since the last noble gas sampling campaign in 2009.

Transport of Sr 2+ and SrEDTA 2- in partially-saturated and heterogeneous sediments

Science.gov (United States)

Pace, M. N.; Mayes, M. A.; Jardine, P. M.; McKay, L. D.; Yin, X. L.; Mehlhorn, T. L.; Liu, Q.; Gürleyük, H.

2007-05-01

Strontium-90 has migrated deep into the unsaturated subsurface beneath leaking storage tanks in the Waste Management Areas (WMA) at the U.S. Department of Energy's (DOE) Hanford Reservation. Faster than expected transport of contaminants in the vadose zone is typically attributed to either physical hydrologic processes such as development of preferential flow pathways, or to geochemical processes such as the formation of stable, anionic complexes with organic chelates, e.g., ethylenediaminetetraacetic acid (EDTA). The goal of this paper is to determine whether hydrological processes in the Hanford sediments can influence the geochemistry of the system and hence control transport of Sr 2+ and SrEDTA 2-. The study used batch isotherms, saturated packed column experiments, and an unsaturated transport experiment in an undisturbed core. Isotherms and repacked column experiments suggested that the SrEDTA 2- complex was unstable in the presence of Hanford sediments, resulting in dissociation and transport of Sr 2+ as a divalent cation. A decrease in sorption with increasing solid:solution ratio for Sr 2+ and SrEDTA 2- suggested mineral dissolution resulted in competition for sorption sites and the formation of stable aqueous complexes. This was confirmed by detection of MgEDTA 2-, MnEDTA 2-, PbEDTA 2-, and unidentified Sr and Ca complexes. Displacement of Sr 2+ through a partially-saturated undisturbed core resulted in less retardation and more irreversible sorption than was observed in the saturated repacked columns, and model results suggested a significant reservoir (49%) of immobile water was present during transport through the heterogeneous layered sediments. The undisturbed core was subsequently disassembled along distinct bedding planes and subjected to sequential extractions. Strontium was unequally distributed between carbonates (49%), ion exchange sites (37%), and the oxide (14%) fraction. An inverse relationship between mass wetness and Sr suggested that

Quantifying sediment sources in a lowland agricultural catchment pond using {sup 137}Cs activities and radiogenic {sup 87}Sr/{sup 86}Sr ratios

Energy Technology Data Exchange (ETDEWEB)

Le Gall, Marion; Evrard, Olivier [Laboratoire des Sciences et de l' Environnement, UMR 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Domaine du CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex (France); Foucher, Anthony [E.A 6293, Laboratoire GéoHydrosystèmes Continentaux (GéHCO), Université F. Rabelais de Tours, Faculté des Sciences et Techniques, Parc de Grandmont, 37200 Tours (France); Laceby, J. Patrick [Laboratoire des Sciences et de l' Environnement, UMR 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Domaine du CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex (France); Salvador-Blanes, Sébastien [E.A 6293, Laboratoire GéoHydrosystèmes Continentaux (GéHCO), Université F. Rabelais de Tours, Faculté des Sciences et Techniques, Parc de Grandmont, 37200 Tours (France); Thil, François; Dapoigny, Arnaud; Lefèvre, Irène [Laboratoire des Sciences et de l' Environnement, UMR 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Domaine du CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex (France); Cerdan, Olivier [Département Risques et Prévention, Bureau de Recherches Géologiques et Minières, 3 avenue Claude Guillemin, 45060 Orléans (France); and others

2016-10-01

Soil erosion often supplies high sediment loads to rivers, degrading water quality and contributing to the siltation of reservoirs and lowland river channels. These impacts are exacerbated in agricultural catchments where modifications in land management and agricultural practices were shown to accelerate sediment supply. In this study, sediment sources were identified with a novel tracing approach combining cesium ({sup 137}Cs) and strontium isotopes ({sup 87}Sr/{sup 86}Sr) in the Louroux pond, at the outlet of a lowland cultivated catchment (24 km{sup 2}, Loire River basin, France) representative of drained agricultural areas of Northwestern Europe. Surface soil (n = 36) and subsurface channel bank (n = 17) samples were collected to characterize potential sources. Deposited sediment (n = 41) was sampled across the entire surface of the pond to examine spatial variation in sediment deposits. In addition, a 1.10 m sediment core was sampled in the middle of the pond to reconstruct source variations throughout time. {sup 137}Cs was used to discriminate between surface and subsurface sources, whereas {sup 87}Sr/{sup 86}Sr ratios discriminated between lithological sources. A distribution modeling approach quantified the relative contribution of these sources to the sampled sediment. Results indicate that surface sources contributed to the majority of pond (μ 82%, σ 1%) and core (μ 88%, σ 2%) sediment with elevated subsurface contributions modeled near specific sites close to the banks of the Louroux pond. Contributions of the lithological sources were well mixed in surface sediment across the pond (i.e., carbonate sediment contribution, μ 48%, σ 1% and non-carbonate sediment contribution, μ 52%, σ 3%) although there were significant variations of these source contributions modeled for the sediment core between 1955 and 2013. These fluctuations reflect both the progressive implementation of land consolidation schemes in the catchment and the eutrophication of

Contributions of Hamstring Stiffness to Straight-Leg-Raise and Sit-and-Reach Test Scores.

Science.gov (United States)

Miyamoto, Naokazu; Hirata, Kosuke; Kimura, Noriko; Miyamoto-Mikami, Eri

2018-02-01

The passive straight-leg-raise (PSLR) and the sit-and-reach (SR) tests have been widely used to assess hamstring extensibility. However, it remains unclear to what extent hamstring stiffness (a measure of material properties) contributes to PSLR and SR test scores. Therefore, we aimed to clarify the relationship between hamstring stiffness and PSLR and SR scores using ultrasound shear wave elastography. Ninety-eight healthy subjects completed the study. Each subject completed PSLR testing, and classic and modified SR testing of the right leg. Muscle shear modulus of the biceps femoris, semitendinosus, and semimembranosus was quantified as an index of muscle stiffness. The relationships between shear modulus of each muscle and PSLR or SR scores were calculated using Pearson's product-moment correlation coefficients. Shear modulus of the semitendinosus and semimembranosus showed negative correlations with the two PSLR and two SR scores (absolute r value≤0.484). Shear modulus of the biceps femoris was significantly correlated with the PSLR score determined by the examiner and the modified SR score (absolute r value≤0.308). The present findings suggest that PSLR and SR test scores are strongly influenced by factors other than hamstring stiffness and therefore might not accurately evaluate hamstring stiffness. © Georg Thieme Verlag KG Stuttgart · New York.

Beta dosimetry in teeth from SR-90 exposed subjects

International Nuclear Information System (INIS)

Fattibene, P.; De Coste, V.; Onori, S.; Veronese, I.; Giussani, A.; Cantone, M.C.; Shishkina, E.

2006-01-01

Tooth enamel is a well recognized dosimeter for retrospective dose reconstruction of individuals accidentally exposed to ionizing radiation. The measurements of the absorbed dose in tooth enamel is conventionally carried out with the Electron Paramagnetic Resonance technique. Tooth enamel is sensitive to all kind of ionizing radiation. Its response to photons has been widely investigated. For application to contaminated teeth with 90 Sr, one of the most common osteo tropic radionuclides, the effectiveness of tooth enamel response to the β spectrum needs be evaluated. The response function to 90 Sr of the EPR/tooth enamel systems, its linearity and reproducibility have been investigated under a controlled geometry, and the results will be presented and compared to those obtained with photons. When the subject has been exposed to both external and internal radiation, a combined EPR/T.L. method can be used to distinguish the internal from the external contribution to the cumulative dose in tooth (Gosku et al., 2002;=Veronese et al. 2004, Shishkina et al. 2005). The T.L. measurement, performed putting thin ± Al 2 O 3 :C dosimeters at contact with the tooth surfaces, enables to estimate the beta dose rate due to the radionuclides present in tooth. The combination of this information with that coming from EPR allows, under specific assumptions, to evaluate separately the internal and external contribution to the tooth dose. In a previous work (Veronese et al., 2004) the dose in enamel measured by EPR in a tooth contaminated with 90 Sr of a Techa River resident was compared to the dose rate measured by TLDs. The test has been extended to a larger number of 90 Sr contaminated teeth. EPR measurements have been also performed in other portions of the teeth, i.e. tooth dentin and root. The correlation between the results, obtained from EPR and TLD measurements, and the evaluation of the relative proportion of internal and external dose are presented and discussed. (authors)

β-Adrenergic induced SR Ca2+ leak is mediated by an Epac-NOS pathway.

Science.gov (United States)

Pereira, Laëtitia; Bare, Dan J; Galice, Samuel; Shannon, Thomas R; Bers, Donald M

2017-07-01

Cardiac β-adrenergic receptors (β-AR) and Ca 2+ -Calmodulin dependent protein kinase (CaMKII) regulate both physiological and pathophysiological Ca 2+ signaling. Elevated diastolic Ca 2+ leak from the sarcoplasmic reticulum (SR) contributes to contractile dysfunction in heart failure and to arrhythmogenesis. β-AR activation is known to increase SR Ca 2+ leak via CaMKII-dependent phosphorylation of the ryanodine receptor. Two independent and reportedly parallel pathways have been implicated in this β-AR-CaMKII cascade, one involving exchange protein directly activated by cAMP (Epac2) and another involving nitric oxide synthase 1 (NOS1). Here we tested whether Epac and NOS function in a single series pathway to increase β-AR induced and CaMKII-dependent SR Ca 2+ leak. Leak was measured as both Ca 2+ spark frequency and tetracaine-induced shifts in SR Ca 2+ , in mouse and rabbit ventricular myocytes. Direct Epac activation by 8-CPT (8-(4-chlorophenylthio)-2'-O-methyl-cAMP) mimicked β-AR-induced SR Ca 2+ leak, and both were blocked by NOS inhibition. The same was true for myocyte CaMKII activation (assessed via a FRET-based reporter) and ryanodine receptor phosphorylation. Inhibitor and phosphorylation studies also implicated phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt) downstream of Epac and above NOS activation in this pathway. We conclude that these two independently characterized parallel pathways function mainly via a single series arrangement (β-AR-cAMP-Epac-PI3K-Akt-NOS1-CaMKII) to mediate increased SR Ca 2+ leak. Thus, for β-AR activation the cAMP-PKA branch effects inotropy and lusitropy (by effects on Ca 2+ current and SR Ca 2+ -ATPase), this cAMP-Epac-NOS pathway increases pathological diastolic SR Ca 2+ leak. This pathway distinction may allow novel SR Ca 2+ leak therapeutic targeting in treatment of arrhythmias in heart failure that spare the inotropic and lusitropic effects of the PKA branch. Copyright © 2017 Elsevier Ltd. All

Annual intake of 137Cs and 90Sr from ingestion of main foodstuffs in Taiwan

International Nuclear Information System (INIS)

Wang, Chih-Jung; Lai, Shu-Ying; Huang, Ching-Chung; Lin, Yu-ming

1996-01-01

The radioactivities of eight main foodstuffs were investigated during 1985-1994 to evaluate the annual intake from the ingestion of 137 Cs and 90 Sr for the residents of Taiwan. The evaluation of annual intake was based on the results of radiochemical analysis of 90 Sr and gamma-ray spectrometry of 137 Cs as well as annual consumption rates of those foodstuffs in Taiwan. The annual intake 90 Sr and 137 Cs per capita is 13 and 60 Bq, respectively. Among the eight foodstuffs, fruit contributed the most to the annual intake of 90 Sr, vegetable second, rice the third and egg the least. For 137 Cs, rice contributed the most, then fruit, meat the third and flour the least. Based on the new conversion factors from ICRP 60, the annual committed effective doses of Taiwanese due to the ingestion of radionuclides 90 Sr and 137 Cs were estimated to be 3.7 x 10 -7 and 7.8 x 10 -7 Sv, respectively. (author)

Characterization of stem rust resistance gene Sr2 in Indian wheat ...

African Journals Online (AJOL)

SONY

2013-05-01

May 1, 2013 ... accelerating wheat production in the last forty years and ensured food security of the Nation. In the present investigation, Sr2 specific molecular markers were used to assess their efficacy for assessing the deployment of Sr2 gene in Indian wheat cultivars of highly productive north-west plains and stem rust ...

Contributions on ecotoxicology. Proceedings; Beitraege zur Oekotoxikologie. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Hartmann, A.; Brueggemann, R. [eds.

1997-11-01

Ecotoxicological effects can be defined in terms of changes in reaction patterns, processes, structures, and functions of ecosystems. At an all-day workshop at GSF on 10. November 1995 various working groups presented their reports on this subject. Taken together the contributions provide good coverage of the present state of knowledge on ecotoxicology. (orig./SR) [Deutsch] Oekotoxikologische Wirkungen lassen sich als Aenderungen hinsichtlich auftretender Reaktionsmuster, Prozesse, Strukturen und Funktionen von Oekosystemen definieren. 1. Molekulare, noxenbezogene Ebene; 2. Zellebene; 3. Organismenebene; 4. Modellsysteme; 5. Systemebene; Oekotoxikologische Bewertung; Im Rahmen eines ganztaegigen Workshops am 10. November 1995 in der GSF wurden Berichte verschiedener Arbeitsgruppe allen Themenbereichen vorgestellt. (orig./SR)

Magnetically controlled space charge capacitance at La{sub 1-x}Sr{sub x}MnO{sub 3}/Sr{sub x}La{sub 1-x}TiO{sub 3} interfaces

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Rainer; Garcia-Barriocanal, Javier; Leon, Carlos; Santamaria, Jacobo [Facultad de Ciencias Fisicas, Dpto. Fisica Aplicada III, Universidad Complutense de Madrid, GFMC (Spain); Unidad Asociada ' ' Laboratorio de Heteroestructuras con Aplicacion en Espintronica' ' , UCM/CSIC, Madrid (Spain); Varela, Maria [Facultad de Ciencias Fisicas, Dpto. Fisica Aplicada III, Universidad Complutense de Madrid, GFMC (Spain); Oak Ridge National Laboratory, Oak Ridge, TN (United States); Instituto Pluridisciplinar, Universidad Complutense de Madrid (Spain); Garcia-Hernandez, Mar [Instituto de Ciencia de Materiales de Madrid - Consejo Superior de Investigaciones Cientificas (ICMM-CSIC), Madrid (Spain)

2016-08-15

This work reports on magnetocapacitance (MC) effects in epitaxial heterostructures of nominally 15 unit cells (u.c.) LaMnO{sub 3} (LMO) and 2 u.c. SrTiO{sub 3} (STO) with an alternating layer-repetition rate of 8: (LMO{sub 15}/STO{sub 2}){sub 8}. Epitaxial multilayer growth at high temperatures (900 C) activates a selective inter-diffusion of La{sup 3+} and Sr{sup 2+} cations across the interfaces, which gives rise to Sr p-doping of the LMO and La n-doping of the STO layers. MC effects at the buried La{sub 1-x}Sr{sub x}MnO{sub 3}/Sr{sub x}La{sub 1-x}TiO{sub 3} (LSMO/SLTO) interfaces are probed by frequency, temperature and magnetic field dependent AC impedance spectroscopy. The technique is shown to be appropriate to account for the separate analysis of different resistance and capacitance contributions at the buried interfaces. As a result of the La/Sr inter-diffusion process, Schottky barriers are formed at the LSMO/SLTO interfaces, which give rise to massive MC of up to ∼ -200% in the out-of-plane film direction. The capacitance of the manganite-titanate LSMO/SLTO interfaces may be coupled indirectly to the resistance of the LSMO layers, because the Schottky space-charge layers and their capacitance can be modulated by varying the concentration of highly mobile charge carriers in the LSMO with a magnetic field. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Comparison of the Sr isotopic signatures in brines of the Canadian and Fennoscandian shields

International Nuclear Information System (INIS)

Negrel, Philippe; Casanova, Joel

2005-01-01

A synthesis of Sr isotope data from shallow and deep groundwaters, and brines from the Fennoscandian and Canadian Shields is presented. A salinity gradient is evident in the water with concentrations varying from approximately 1-75 g L -1 below 1500 m depth in the Fennoscandian Shield and from 10 up to 300 g L -1 below 650 m depth in the Canadian Shield. Strontium isotope ratios were measured to assess the origin of the salinity and evaluate the degree of water-rock interaction in the systems. In both shields, the Sr concentrations are enriched relative to Cl, defining a positive trend parallel to the seawater dilution line and indicative of Sr addition through weathering processes. The depth distribution for Sr concentration increases strongly with increasing depth in both shields although the variation in Sr-isotope composition does not mirror that of Sr concentrations. Strontium-isotope compositions are presented for surface waters, and groundwaters in several sites in the Fennoscandian and Canadian Shields. Numerous mixing lines can be drawn reflecting water-rock interaction. A series of calculated lines links the surface end-members (surface water and shallow groundwater) and the deep brines; these mixing lines define a range of 87 Sr/ 86 Sr ratios for the deep brines in different selected sites. All sites show a specific 87 Sr/ 86 Sr signature and the occurrence of large 87 Sr/ 86 Sr variations is site specific in both shields. In Canadian Shield brines, the Sr isotope ratios clearly highlight large water rock interaction that increases the 87 Sr/ 86 Sr ratio from water that could have been of marine origin. In contrast to the Canadian Shield, groundwater does not occur in closed pockets in the Fennoscandian, and the well-constrained 87 Sr/ 86 Sr signatures in deep brines should correspond to a large, well-mixed and homogeneous water reservoir, whose Sr isotope signature results from water-rock interaction

Biosphere analyses for the safety assessment SR-Site - synthesis and summary of results

International Nuclear Information System (INIS)

Saetre, Peter

2010-12-01

This report summarises nearly 20 biosphere reports and gives a synthesis of the work performed within the SR-Site Biosphere project, i.e. the biosphere part of SR-Site. SR-Site Biosphere provides the main project with dose conversion factors (LDFs), given a unit release rate, for calculation of human doses under different release scenarios, and assesses if a potential release from the repository would have detrimental effects on the environment. The intention of this report is to give sufficient details for an overview of methods, results and major conclusions, with references to the biosphere reports where methods, data and results are presented and discussed in detail. The philosophy of the biosphere assessment was to make estimations of the radiological risk for humans and the environment as realistic as possible, based on the knowledge of present-day conditions at Forsmark and the past and expected future development of the site. This was achieved by using the best available knowledge, understanding and data from extensive site investigations from two sites. When sufficient information was not available, uncertainties were handled cautiously. A systematic identification and evaluation of features and processes that affect transport and accumulation of radionuclides at the site was conducted, and the results were summarised in an interaction matrix. Data and understanding from the site investigation was an integral part of this work, the interaction matrix underpinned the development of the radionuclide model used in the biosphere assessment. Understanding of the marine, lake and river and terrestrial ecosystems at the site was summarized in a conceptual model, and relevant features and process have been characterized to capture site specific parameter values. Detailed investigations of the structure and history of the regolith at the site and simulations of regolith dynamics were used to describe the present day state at Forsmark and the expected development of

Using 87Sr/86Sr ratios to investigate changes in stream chemistry during snowmelt in the Provo River, Utah, USA

Science.gov (United States)

Hale, C. A.; Carling, G. T.; Fernandez, D. P.; Nelson, S.; Aanderud, Z.; Tingey, D. G.; Dastrup, D.

2017-12-01

Water chemistry in mountain streams is variable during spring snowmelt as shallow groundwater flow paths are activated in the watershed, introducing solutes derived from soil water. Sr isotopes and other tracers can be used to differentiate waters that have interacted with soils and dust (shallow groundwater) and bedrock (deep groundwater). To investigate processes controlling water chemistry during snowmelt, we analyzed 87Sr/86Sr ratios, Sr and other trace element concentrations in bulk snowpack, dust, soil, soil water, ephemeral channels, and river water during snowmelt runoff in the upper Provo River watershed in northern Utah, USA, over four years (2014-2017). Strontium concentrations in the river averaged 20 ppb during base flow and decreased to 10 ppb during snowmelt runoff. 87Sr/86Sr ratios were around 0.717 during base flow and decreased to 0.715 in 2014 and 0.713 in 2015 and 2016 during snowmelt, trending towards less radiogenic values of mineral dust inputs in the Uinta Mountain soils. Ephemeral channels, representing shallow flow paths with soil water inputs, had Sr concentrations between 7-20 ppb and 87Sr/86Sr ratios between 0.713-0.716. Snowpack Sr concentrations were generally soils that contain accumulated dust deposits with a less radiogenic 87Sr/86Sr ratio. These results suggest that flow paths and atmospheric dust are important to consider when investigating variable solute loads in mountain streams.

Precessional control of Sr ratios in marginal basins during the Messinian Salinity Crisis?

Science.gov (United States)

Topper, R. P. M.; Lugli, S.; Manzi, V.; Roveri, M.; Meijer, P. Th.

2014-05-01

Based on 87Sr/86Sr data of the Primary Lower Gypsum (PLG) deposits in the Vena del Gesso basin—a marginal basin of the Mediterranean during the Messinian Salinity Crisis—a correlation between 87Sr/86Sr values and precessional forcing has recently been proposed but not yet confirmed. In this study, a box model is set up to represent the Miocene Mediterranean deep basin and a connected marginal basin. Measurements of 87Sr/86Sr in the Vena del Gesso and estimated salinity extrema are used to constrain model results. In an extensive analysis with this model, we assess whether coeval 87Sr/86Sr and salinity fluctuations could have been forced by precession-driven changes in the fresh water budget. A comprehensive set of the controlling parameters is examined to assess the conditions under which precession-driven 87Sr/86Sr variations occur and to determine the most likely setting for PLG formation. Model results show that precession-driven 87Sr/86Sr and salinity fluctuations in marginal basins are produced in settings within a large range of marginal basin sizes, riverine strontium characteristics, amplitudes of precessional fresh water budget variation, and average fresh water budgets of both the marginal and deep basin. PLG deposition most likely occurred when the Atlantic-Mediterranean connection was restricted, and the average fresh water budget in the Mediterranean was significantly less negative than at present day. Considering the large range of settings in which salinities and 87Sr/86Sr fluctuate on a precessional timescale, 87Sr/86Sr variations are expected to be a common feature in PLG deposits in marginal basins of the Mediterranean.

Principles of μSR technics

International Nuclear Information System (INIS)

Chappert, J.

1983-05-01

Principles of muon spin rotation spectroscopy (μSR) are presented. Muons plus are only take into account because physical and chemical results obtained presently are obtained by them. Muon plus has two main characteristics when implanted in a sample: just, it can be considered as a interstitial site probe; then the muon plus can diffuse. Accordingly the quantities measured by μSR are a combination of static and dynamic properties of the muon plus and of the sample. A fluid characteristics is the possibility of munomium formation (μ + e - bound state) [fr

Construction of the seawater 87Sr/86Sr curve for the Cenozoic and Cretaceous: supporting data

International Nuclear Information System (INIS)

Koepnick, R.B.; Burke, W.H.; Denison, R.E.; Hetherington, E.A.; Nelson, H.F.; Otto, J.B.; Waite, L.E.

1985-01-01

We present the data used to construct the Cenozoic and Cretaceous portion of the Phanerozoic curve of seawater 87 Sr/ 86 Sr that had been given in summary form by W.H. Burke and coworkers. All Cenozoic samples (128) and 22 Cretaceous samples are foram-nannofossil oozes and limestones from DSDP cores distributed among 13 sites in the Atlantic, Pacific and Indian Oceans, and the Caribbean Sea. Non-DSDP Cretaceous samples (126) include limestone, anhydrite and phosphate samples from North America, Europe and Asia. Determination of the 87 Sr/ 86 Sr value of seawater at particular times in the past is based on comparison of ratios derived from coeval marine samples from widely separated geographic areas. The general configuration of the Cenozoic and Cretaceous curve appears to be strongly influenced by the history of plate interactions and sea-floor spreading. Specific rises and falls in the 87 Sr/ 86 Sr of seawater, however, may be caused by a variety of factors such as variation in lithologic composition of the crust exposed to weathering, configuration and topographic relief of continents, volcanic activity, rate of sea-floor spreading, extent of continental inundation by epeiric seas, and variations in both climate and paleo-oceanographic conditions. Many or all of these factors are probably related to global tectonic processes, yet their combined effect on the temporal variation of seawater 87 Sr/ 86 Sr can complicate a direct plate-tectonic interpretation for portions of the seawater curve. (Auth.)

Discrete-Feature Modelling of Groundwater Flow and Solute Transport for SR-Can Review. External review contribution in support of SKI's and SSI's review of SR-Can

Energy Technology Data Exchange (ETDEWEB)

Geier, Joel (Clearwater Hardrock Consulting, Corvallis, OR (US))

2008-03-15

Discrete-feature models were developed to represent the main classes of water-conducting features at the Laxemar and Forsmark candidate sites for a high-level radioactive waste repository. The models encompass features on scales ranging from individual fractures 2 m or larger in radius around deposition holes, or spalled zones around deposition holes and tunnels, to deformation zones on the scale of kilometres. Equivalent discontinuum features are used to represent the aggregate properties of fractures outside of the vicinity of deposition holes where an explicit representation is used. Deposition hole locations within the repository layout are conditioned to each stochastic realization of the discrete-fracture population, using a full-perimeter-intersection criterion to identify discriminating fractures that pose a seismic risk, and a simulated pilot-hole criterion to exclude deposition-hole locations with excessive flows. The utilization factors of 0.70 obtained here for the full repository at Forsmark and = 0.53 for the full repository at Laxemar are significantly lower than the corresponding values = 0.93 and 0.88 for the most nearly comparable case presented in the SR-Can Main Report. Further investigation is needed to discern whether this discrepancy is primarily due to possible nonconservative assumptions in SKB's analytical modelling approach, or due to artefacts of the simulation approach using finite domains, which could lead to overly conservative values in the present study. Flows through the discrete-feature model variants are calculated by finite-element simulation. Distributions of flows to deposition holes are presented for the Laxemar base case and for an initial suite of variants for Forsmark. Results for Forsmark indicate that the distribution of flow to deposition holes is robust with respect to the set of variants considered, and that a given single realization of the discrete-fracture network (DFN) submodel produces representative results

What nuclear power can contribute

International Nuclear Information System (INIS)

Schwarz, D.

1997-01-01

The big tasks of mankind are: Development, protection of the environment, peace, and saving of resources on behalf of coming generations. Poverty exerts the greatest stress upon nature, development and protection of the environment are therefore not contradictory. Mankind has enough energy and mineral resources (sources), enough technology to limit detrimental effluents (taking care of sinks), and enough capital to bring about well-being for all mankind. Well-being decelerates population growth; in this way a stable coexistence of man and nature can be achieved. To this goal, nuclear energy can contribute significantly. Even at a considerably higher level of exploitation, it would last for several 100 000 years. Nuclear energy can supply every kind of energy required and, jointly with higher efficiency, it can do so at low cost; as to that, nuclear energy is superior to renewable energies in most cases. Also, nuclear energy can be deployed quickly enough. At the present safety level (including fuel cycle) the risks of deploying nuclear energy are smaller than the risks of non-deployment, by several orders of magnitude, both with respect to risk magnitude and probability. The material basis for a sustainable well-being of man and nature on this earth does exist. To-day's prime issue is to remove mental road blocks. (orig.) [de

Groundwater chemistry around a repository for spent nuclear fuel over a glacial cycle. Evaluation for SR-Can

Energy Technology Data Exchange (ETDEWEB)

Auque, L.F.; Gimeno, M.J.; Gomez, J.B. [University of Zaragoza (Spain); Puigdomenech, I. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Smellie, J. [Conterra AB, Uppsala (Sweden); Tullborg, E.L. [Terralogica AB, Graabo (Sweden)

2007-12-15

The chemical composition of groundwater in the rock volume surrounding a spent nuclear fuel repository is of importance to many factors that affect repository performance. The geochemical characteristics of present-day Swedish groundwater systems are governed by successive mixing events of several waters during the post-glacial evolution of the sites. The expected development of groundwaters at two Swedish sites - Forsmark and Laxemar - during a glacial cycle has been evaluated within the SR-Can project, and the results are presented in this report. For the temperate period following repository closure, an approach is proposed here to investigate the spatial and temporal evolution of groundwater geochemistry by coupling hydrogeological and geochemical models in a sequential way. The procedure combines hydrogeological results obtained with CONNECTFLOW within the SR-Can project with a mixing and reaction path simulation using PHREEQC. The hydrological results contain mixing proportions of four component waters (a deep brine, glacial meltwater, marine water, and meteoric infiltration) at each time step and at every node of the D regional model domain. In this work the mixing fractions are fed into PHREEQC using software developed to build formatted input files and to extract the information from output files for subsequent plotting and analysis. The geochemical calculations included both chemical mixing and equilibrium reactions with selected minerals: calcite, chalcedony and an Fe(III) oxy-hydroxide. Results for the Forsmark and Laxemar sites are graphically presented as histograms and box-and-whisker plots. Cross sections, where each node is colour-coded with respect to an important variable (pH, Eh or concentrations of main elements), are used to visualize the future evolution of the site. Sensitivity analyses are made to evaluate the effects of the different reactions and/or assumptions. The results reflect the progressive inflow of meteoric waters into the sites

Groundwater chemistry around a repository for spent nuclear fuel over a glacial cycle. Evaluation for SR-Can

International Nuclear Information System (INIS)

Auque, L.F.; Gimeno, M.J.; Gomez, J.B.; Puigdomenech, I.; Smellie, J.; Tullborg, E.L.

2007-12-01

The chemical composition of groundwater in the rock volume surrounding a spent nuclear fuel repository is of importance to many factors that affect repository performance. The geochemical characteristics of present-day Swedish groundwater systems are governed by successive mixing events of several waters during the post-glacial evolution of the sites. The expected development of groundwaters at two Swedish sites - Forsmark and Laxemar - during a glacial cycle has been evaluated within the SR-Can project, and the results are presented in this report. For the temperate period following repository closure, an approach is proposed here to investigate the spatial and temporal evolution of groundwater geochemistry by coupling hydrogeological and geochemical models in a sequential way. The procedure combines hydrogeological results obtained with CONNECTFLOW within the SR-Can project with a mixing and reaction path simulation using PHREEQC. The hydrological results contain mixing proportions of four component waters (a deep brine, glacial meltwater, marine water, and meteoric infiltration) at each time step and at every node of the D regional model domain. In this work the mixing fractions are fed into PHREEQC using software developed to build formatted input files and to extract the information from output files for subsequent plotting and analysis. The geochemical calculations included both chemical mixing and equilibrium reactions with selected minerals: calcite, chalcedony and an Fe(III) oxy-hydroxide. Results for the Forsmark and Laxemar sites are graphically presented as histograms and box-and-whisker plots. Cross sections, where each node is colour-coded with respect to an important variable (pH, Eh or concentrations of main elements), are used to visualize the future evolution of the site. Sensitivity analyses are made to evaluate the effects of the different reactions and/or assumptions. The results reflect the progressive inflow of meteoric waters into the sites

EPR and TL-based beta dosimetry measurements in various tooth components contaminated by 90Sr

International Nuclear Information System (INIS)

Veronese, I.; Fattibene, P.; Cantone, M.C.; De Coste, V.; Giussani, A.; Onori, S.; Shishkina, E.A.

2008-01-01

Thermoluminescence-based beta dosimetry, previously proposed for the estimate of the internal contamination in teeth, and EPR has been used in this paper to investigate the homogeneity of 90 Sr contamination and of dose within nine teeth of one person born in the year of the onset of waterborne radioactive releases of the Mayak plutonium facility. A large deviation of dose and activity distributions in both enamel and radical dentine of the various teeth was observed. Average dose was 27±7Gy in enamel and 0.90±0.31Gy in radical dentine. Average 90 Sr concentration was 52±8Bq/g in enamel and 5±2Bq/g in radical dentine. The observed deviation around the mean value of dose and 90 Sr concentration can be explained due to the specific mineral evolution of each tooth at the time of Sr intake. In the same donor, a negative correlation was also observed between radical dentine and enamel for the 90 Sr specific activity as well for the dose. Similar analyses performed on one massive molar belonging to a second donor revealed absence of correlation between dose and 90 Sr concentration in the same tissue, indicating a dose contribution from 90 Sr present in neighbouring tissue compartments. Systematic differences in cumulated dose and activity levels between the lingual and the buccal parts of crown dentine and of enamel were also observed

82Sr--82Rb radioisotope generator

International Nuclear Information System (INIS)

Grant, P.M.; Erdal, B.R.; O'Brien, H.A.

1976-01-01

An improved 82 Sr- 82 Rb radioisotope generator system, based upon the complexing ion exchange resin Chelex-100, has been developed. Columns of this material can be easily and rapidly milked, and the Rb-Sr separation factor for a fresh generator was found to be greater than 10 7 . Approximately 80 percent of the 82 Rb present was delivered in a 15-ml volume of aqueous 0.2 M NH 4 Cl solution. After more than 6 liters of eluant had been put through the generator, the Rb-Sr separation factor was still observed to be greater than 10 5 , and no unusual strontium breakthrough behavior was seen in the system over nearly three 82 Sr half lives. 2 claims, no drawings

Metastable honeycomb SrTiO_3/SrIrO_3 heterostructures

International Nuclear Information System (INIS)

Anderson, T. J.; Ryu, S.; Podkaminer, J. P.; Ma, Y.; Eom, C. B.; Zhou, H.; Xie, L.; Irwin, J.; Rzchowski, M. S.; Pan, X. Q.

2016-01-01

Recent theory predictions of exotic band topologies in (111) honeycomb perovskite SrIrO_3 layers sandwiched between SrTiO_3 have garnered much attention in the condensed matter physics and materials communities. However, perovskite SrIrO_3 film growth in the (111) direction remains unreported, as efforts to synthesize pure SrIrO_3 on (111) perovskite substrates have yielded films with monoclinic symmetry rather than the perovskite structure required by theory predictions. In this study, we report the synthesis of ultra-thin metastable perovskite SrIrO_3 films capped with SrTiO_3 grown on (111) SrTiO_3 substrates by pulsed laser deposition. The atomic structure of the ultra-thin films was examined with scanning transmission electron microscopy (STEM), which suggests a perovskite layering distinct from the bulk SrIrO_3 monoclinic phase. In-plane 3-fold symmetry for the entire heterostructure was confirmed using synchrotron surface X-ray diffraction to measure symmetry equivalent crystal truncation rods. Our findings demonstrate the ability to stabilize (111) honeycomb perovskite SrIrO_3, which provides an experimental avenue to probe the phenomena predicted for this material system.

Bioethicists Can and Should Contribute to Addressing Racism

Science.gov (United States)

Danis, Marion; Wilson, Yolonda; White, Amina

2016-01-01

The problems of racism and racially-motivated violence in predominantly African American communities in the US are complex, multifactorial and historically rooted. While these problems are also deeply morally troubling, bioethicists have not contributed substantially to addressing them. Concern for justice has been one of the core commitments of bioethics. For this and other reasons, bioethicists should contribute to addressing these problems. We consider how bioethicists can offer meaningful contributions to the public discourse, research, teaching, training, policy development and academic scholarship in response to the alarming and persistent patterns of racism and implicit biases associated with it. To make any useful contribution, bioethicists will require preparation and should expect to play a significant role through collaborative action with others. PMID:26982911

Bioethicists Can and Should Contribute to Addressing Racism.

Science.gov (United States)

Danis, Marion; Wilson, Yolonda; White, Amina

2016-01-01

The problems of racism and racially motivated violence in predominantly African American communities in the United States are complex, multifactorial, and historically rooted. While these problems are also deeply morally troubling, bioethicists have not contributed substantially to addressing them. Concern for justice has been one of the core commitments of bioethics. For this and other reasons, bioethicists should contribute to addressing these problems. We consider how bioethicists can offer meaningful contributions to the public discourse, research, teaching, training, policy development, and academic scholarship in response to the alarming and persistent patterns of racism and implicit biases associated with it. To make any useful contribution, bioethicists will require preparation and should expect to play a significant role through collaborative action with others.

RADIOISOTOPE INVENTORY FOR TSPA-SR

International Nuclear Information System (INIS)

Leigh, C.; Rechard, R.

2001-01-01

The total system performance assessment for site recommendation (TSPA-SR), on Yucca Mountain, as a site (if suitable) for disposal of radioactive waste, consists of several models. The Waste Form Degradation Model (i.e, source term) of the TSPA-SR, in turn, consists of several components. The Inventory Component, discussed here, defines the inventory of 26 radioisotopes for three representative waste categories: (1) commercial spent nuclear fuel (CSNF), (2) US Department of Energy (DOE) spent nuclear fuel (DSNF), and (3) high-level waste (HLW). These three categories are contained and disposed of in two types of waste packages (WPs)--CSNF WPs and co-disposal WPs, with the latter containing both DSNF and HLW. Three topics are summarized in this paper: first, the transport of radioisotopes evaluated in the past; second, the development of the inventory for the two WP types; and third, the selection of the most important radioisotopes to track in TSPA-SR

Landscape dose conversion factors used in the safety assessment SR-Site

International Nuclear Information System (INIS)

Avila, Rodolfo; Ekstroem, Per-Anders; Aastrand, Per-Gustav

2010-12-01

In this report two types of Dose Conversion Factors have been derived: i) a Landscape Dose Conversion Factor (LDF) that is applicable to continuous long-term releases to the biosphere at a constant rate, and ii) a Landscape Dose Conversion Factor for pulse releases (LDF pulse) that is applicable to a radionuclide release that reaches the biosphere in a pulse within years to hundreds of years. In SR-Site these Dose Factors are multiplied with modelled release rates or pulse releases from the geosphere to obtain dose estimates used in assessment of compliance with the regulatory risk criterion. The LDFs were calculated for three different periods of the reference glacial cycle; a period of submerged conditions following the deglaciation, the temperate period, and a prolonged period of periglacial conditions. Additionally, LDFs were calculated for the global warming climate case. The LDF pulse was calculated only for temperate climate conditions. The LDF and LDF pulse can be considered as Best Estimate values, which can be used in calculations of Best Estimate values of doses to a representative individual of the most exposed group from potential releases from a future repository. A systematic analysis of the effects of system, model and parameter uncertainties on the LDFs has been carried out. This analysis has shown that the use of the derived LDF would lead to cautious or realistic dose estimates. The models and methods that were used for derivation of the LDFs and LDF pulse are also described in this report

Landscape dose conversion factors used in the safety assessment SR-Site

Energy Technology Data Exchange (ETDEWEB)

Avila, Rodolfo; Ekstroem, Per-Anders; Aastrand, Per-Gustav (Facilia AB (Sweden))

2010-12-15

In this report two types of Dose Conversion Factors have been derived: i) a Landscape Dose Conversion Factor (LDF) that is applicable to continuous long-term releases to the biosphere at a constant rate, and ii) a Landscape Dose Conversion Factor for pulse releases (LDF pulse) that is applicable to a radionuclide release that reaches the biosphere in a pulse within years to hundreds of years. In SR-Site these Dose Factors are multiplied with modelled release rates or pulse releases from the geosphere to obtain dose estimates used in assessment of compliance with the regulatory risk criterion. The LDFs were calculated for three different periods of the reference glacial cycle; a period of submerged conditions following the deglaciation, the temperate period, and a prolonged period of periglacial conditions. Additionally, LDFs were calculated for the global warming climate case. The LDF pulse was calculated only for temperate climate conditions. The LDF and LDF pulse can be considered as Best Estimate values, which can be used in calculations of Best Estimate values of doses to a representative individual of the most exposed group from potential releases from a future repository. A systematic analysis of the effects of system, model and parameter uncertainties on the LDFs has been carried out. This analysis has shown that the use of the derived LDF would lead to cautious or realistic dose estimates. The models and methods that were used for derivation of the LDFs and LDF pulse are also described in this report

Performance Assessment and Sensitivity Analyses of Disposal of Plutonium as Can-in-Canister Ceramic

International Nuclear Information System (INIS)

Rainer Senger

2001-01-01

The purpose of this analysis is to examine whether there is a justification for using high-level waste (HLW) as a surrogate for plutonium disposal in can-in-canister ceramic in the total-system performance assessment (TSPA) model for the Site Recommendation (SR). In the TSPA-SR model, the immobilized plutonium waste form is not explicitly represented, but is implicitly represented as an equal number of canisters of HLW. There are about 50 metric tons of plutonium in the U. S. Department of Energy inventory of surplus fissile material that could be disposed. Approximately 17 tons of this material contain significant quantities of impurities and are considered unsuitable for mixed-oxide (MOX) reactor fuel. This material has been designated for direct disposal by immobilization in a ceramic waste form and encapsulating this waste form in high-level waste (HLW). The remaining plutonium is suitable for incorporation into MOX fuel assemblies for commercial reactors (Shaw 1999, Section 2). In this analysis, two cases of immobilized plutonium disposal are analyzed, the 17-ton case and the 13-ton case (Shaw et al. 2001, Section 2.2). The MOX spent-fuel disposal is not analyzed in this report. In the TSPA-VA (CRWMS M and O 1998a, Appendix B, Section B-4), the calculated dose release from immobilized plutonium waste form (can-in-canister ceramic) did not exceed that from an equivalent amount of HLW glass. This indicates that the HLW could be used as a surrogate for the plutonium can-in-canister ceramic. Representation of can-in-canister ceramic as a surrogate is necessary to reduce the number of waste forms in the TSPA model. This reduction reduces the complexity and running time of the TSPA model and makes the analyses tractable. This document was developed under a Technical Work Plan (CRWMS M and O 2000a), and is compliant with that plan. The application of the Quality Assurance (QA) program to the development of that plan (CRWMS M and O 2000a) and of this Analysis is

A review of expert judgement and treatment of probability in SR 97

International Nuclear Information System (INIS)

Wilmot, R.D.; Crawford, M.B.

2000-01-01

The Swedish Nuclear Fuel and Waste Management Company (SKB) recently published its latest performance assessment for deep disposal of spent nuclear fuel, based on the KBS-3 concept. This assessment, SR 97, uses three hypothetical repository sites (known as Aberg, Beberg and Ceberg) to provide a range of geological settings and hydrogeological conditions for the assessment. The long-term performance of these sites is compared for several sets of assumptions relating to canister lifetimes, climate evolution, and patterns of human behaviour. This report is a review of SR 97 conducted by Galson Sciences Ltd on behalf of the Swedish Nuclear Power Inspectorate (SKI). The review focussed on the use of expert judgement in the assessment and on the treatment of uncertainty and the use of probability in assessment calculations. The review of SR 97 concluded that SKB had identified many of the judgements made in developing and implementing the assessment and modelling approaches, but that a more formal documentation of the assumptions involved would add to the clarity and transparency of the use of judgements. Similarly, explicit acknowledgement of the basis for making judgements about the treatment of FEPs would improve confidence in the assessment. There are a number of tools that can be useful in justifying the judgements made in an assessment. The review concluded that more use of dialogue with stake holders, peer review and expert elicitation could all be of value in SKB's assessment programme. Recently introduced regulations in Sweden have established an individual risk criterion for the long-term performance of repositories. SKB has previously identified 'pessimistic' and 'reasonable' values for a number of model parameters, and used these in a range of deterministic calculations to calculate dose and to illustrate system performance. To allow for the calculation of risk, SKB introduced probabilistic analyses into the SR 97 assessment by assigning probabilities of 10

Experimental evidence shows no fractionation of strontium isotopes ((87)Sr/(86)Sr) among soil, plants, and herbivores: implications for tracking wildlife and forensic science.

Science.gov (United States)

Flockhart, D T Tyler; Kyser, T Kurt; Chipley, Don; Miller, Nathan G; Norris, D Ryan

2015-01-01

Strontium isotopes ((87)Sr/(86)Sr) can be useful biological markers for a wide range of forensic science applications, including wildlife tracking. However, one of the main advantages of using (87)Sr/(86)Sr values, that there is no fractionation from geological bedrock sources through the food web, also happens to be a critical assumption that has never been tested experimentally. We test this assumption by measuring (87)Sr/(86)Sr values across three trophic levels in a controlled greenhouse experiment. Adult monarch butterflies were raised on obligate larval host milkweed plants that were, in turn, grown on seven different soil types collected across Canada. We found no significant differences between (87)Sr/(86)Sr values in leachable Sr from soil minerals, organic soil, milkweed leaves, and monarch butterfly wings. Our results suggest that strontium isoscapes developed from (87)Sr/(86)Sr values in bedrock or soil may serve as a reliable biological marker in forensic science for a range of taxa and across large geographic areas.

Contribution to knowledge of radiation damage in KCl crystals doped with Sr

International Nuclear Information System (INIS)

Sordi, G.-M.A.A.

1974-11-01

The radiation damages in KCl crystals doped with Sr ++ using thermo-ionic technique (ITC) and optical absorption measurements were studied. The variation of the entropy for the dipole jump starting from results reported by several authors was calculated. The irradiation effects with three different exposures were analysed: irradiation with gamma rays; irradiation with fast neutrons added to gamma irradiation; and irradiation with thermal neutrons together with fast neutrons and gamma rays. (Author) [pt

Fast and sensitive determination of Sr-90 and SR-89 activity in milk by ion-chromatography and liquid scintillation

International Nuclear Information System (INIS)

Figueiredo, V.; Herrmann, A.

1992-01-01

A method for fast and exact determination of both strontium isotopes in milk and other foodstuffs, combination high performance ion chromatographic separation with by liquid scintillation counting, which enables the desired results to be obtained with very satisfactory precision and reproducibility within 24 hours, has been developed. The lowest detectable activity lies by 3 Bq/liter for Sr-90 and 1 Bq/liter for Sr-89 which is satisfactory for assessing a situation in a time crisis. (author)

Distribution of 14C, 90Sr and 228Th in an elephant tusk

International Nuclear Information System (INIS)

Brunnermeier, M.J.; Schmied, S.A.K. Contact Information and Robert Schupfner

2012-01-01

The period of date of death of an elephant can be assessed by analyzing four different radionuclides, 14 C, 90 Sr, 228 Th and 232 Th in its ivory. These nuclides are supposed to have variing concentrations at different parts of a tusk. The reason is the procedure of growth which takes place at the butt-site of a tusk. Therefore the site of sampling could have a big influence on the assessed date of death. However, to find out if the position of sampling is important a complete tusk was analyzed regarding the distribution of these nuclides. Results show that the concentration activity of 14 C and 228 Th varies in different parts of a tusk. The activity concentration of 90 Sr is very similar in all analyzed parts. The conclusion is that sampling at the butt of a tusk is recommended for age assessment. (author)

Rapid method for determining Sr-89 and Sr-90 using Cherenkov and proportional counting; Schnellmethode zur Bestimmung von SR-89 und SR-90 durch Cerenkov- und Proportionalzaehlermessungen

Energy Technology Data Exchange (ETDEWEB)

Lange, S.; Wende, C.; Schwokowski, R.; Alisch-Mark, M.; Abraham, A.; Heinrich, T. [Staatliche Betriebsgesellschaft fuer Umwelt und Landwirtschaft, Radebeul (Germany)

2016-07-01

A rapid method for determining Sr-89 and Sr-90 in water, milk and biological samples has been developed and tested. After sample preparation strontium is separated by extraction chromatography using Sr resin. Eluate is divided and transfered to LSC vial and filter paper by SrCO{sub 3} precipitation. A Hidex 300 SL TDCR liquid scintillation counter and Thermo Fisher low level proportional counter have been used. Chemical yield of Sr-85 tracer is determined by Gamma spectroscopy. Uncertainty budget, decision threshold and detection limit are calculated in accordance with GUM and ISO 11929.

Dispersion and fate of {sup 90}Sr in the Northwestern Pacific and adjacent seas: Global fallout and the Fukushima Dai-ichi accident

Energy Technology Data Exchange (ETDEWEB)

Maderich, V., E-mail: vladmad@gmail.com [Institute of Mathematical Machine and System Problems, Glushkov av., 42, Kiev 03187 (Ukraine); Jung, K.T., E-mail: ktjung@kiost.ac [Korea Institute of Ocean Science and Technology, 787, Haean-ro, Ansan 426-744 (Korea, Republic of); Bezhenar, R., E-mail: romanbezhenar@gmail.com [Ukrainian Center of Water and Environmental Projects, Glushkov av., 42, Kiev 03187 (Ukraine); With, G. de, E-mail: g.dewith@nrg.eu [NRG, Utrechtseweg 310, 6800 ES Arnhem (Netherlands); Qiao, F., E-mail: qiaofl@fio.org.cn [First Institute of Oceanography, 6 Xianxialing Road, Qingdao 266061 (China); Casacuberta, N., E-mail: ncasacuberta@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH-Zurich, Schafmattstrasse 20, 8093 Zurich (Switzerland); Masque, P., E-mail: pere.masque@uab.cat [Institut de Ciència i Tecnologia Ambientals and Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra (Spain); Kim, Y.H., E-mail: yhkimstar@gmail.com [Korea Institute of Ocean Science and Technology, 787, Haean-ro, Ansan 426-744 (Korea, Republic of)

2014-10-01

The 3D compartment model POSEIDON-R was applied to the Northwestern Pacific and adjacent seas to simulate the transport and fate of {sup 90}Sr in the period 1945–2010 and to perform a radiological assessment on the releases of {sup 90}Sr due to the Fukushima Dai-ichi nuclear accident for the period 2011–2040. The contamination due to runoff of {sup 90}Sr from terrestrial surfaces was taken into account using a generic predictive model. A dynamical food-chain model describes the transfer of {sup 90}Sr to phytoplankton, zooplankton, molluscs, crustaceans, piscivorous and non-piscivorous fishes. Results of the simulations were compared with observation data on {sup 90}Sr for the period 1955–2010 and the budget of {sup 90}Sr activity was estimated. It was found that in the East China Sea and Yellow Sea the riverine influx was 1.5% of the ocean influx and it was important only locally. Calculated concentrations of {sup 90}Sr in water, bottom sediment and marine organisms before and after the Fukushima Dai-ichi accident are in good agreement with available experimental measurements. The concentration of {sup 90}Sr in seawater would return to the background levels within one year after leakages were stopped. The model predicts that the concentration of {sup 90}Sr in fish after the Fukushima Dai-ichi accident shall return to the background concentrations only 2 years later due to the delay of the transfer throughout the food web and specific accumulation of {sup 90}Sr. The contribution of {sup 90}Sr to the maximal dose rate due to the FDNPP accident was three orders of magnitude less than that due to {sup 137}Cs, and thus well below the maximum effective dose limits for the public. - Highlights: • A box model with a dynamical food-chain model for the NW Pacific was applied. • The transport and fate of {sup 90}Sr in sea were simulated for the period 1945–2040. • Marine exposure pathways for {sup 90}Sr were assessed for the Fukushima Dai-ichi accident. �

87Sr/86Sr as a quantitative geochemical proxy for 14C reservoir age in dynamic, brackish waters: assessing applicability and quantifying uncertainties.

Science.gov (United States)

Lougheed, Bryan; van der Lubbe, Jeroen; Davies, Gareth

2016-04-01

Accurate geochronologies are crucial for reconstructing the sensitivity of brackish and estuarine environments to rapidly changing past external impacts. A common geochronological method used for such studies is radiocarbon (14C) dating, but its application in brackish environments is severely limited by an inability to quantify spatiotemporal variations in 14C reservoir age, or R(t), due to dynamic interplay between river runoff and marine water. Additionally, old carbon effects and species-specific behavioural processes also influence 14C ages. Using the world's largest brackish water body (the estuarine Baltic Sea) as a test-bed, combined with a comprehensive approach that objectively excludes both old carbon and species-specific effects, we demonstrate that it is possible to use 87Sr/86Sr ratios to quantify R(t) in ubiquitous mollusc shell material, leading to almost one order of magnitude increase in Baltic Sea 14C geochronological precision over the current state-of-the-art. We propose that this novel proxy method can be developed for other brackish water bodies worldwide, thereby improving geochronological control in these climate sensitive, near-coastal environments.

Sr isotope ratio in the rainwater from Ahmedabad, an urban site in India

International Nuclear Information System (INIS)

Chatterjee, Jayati; Singh, Sunil K.

2011-01-01

The rain water Sr was measured at Ahmedabad to get an idea about the various sources of dissolved ions to rain water. The present study shows the Deccan trap as an important source of Sr during the south west monsoon. Occasional contributions from other lithologies such as alluvium of the Ganga system have also been observed during this study

Environmental 90Sr measurements

Science.gov (United States)

Paul, M.; Berkovits, D.; Cecil, L.D.; Feldstein, H.; Hershkowitz, A.; Kashiv, Y.; Vogt, S.

1997-01-01

90Sr (T1/2 = 28.5 years) is a long-lived radionuclide produced in nuclear fission. Fast radiochemical detection of 90Sr in environmental samples is not feasible using current analytical methods. Accelerator Mass Spectrometry (AMS) measurements of 90Sr were made with the Rehovot 14UD Pelletron accelerator at a terminal voltage of 11 or 12 MV using our standard detection system. Injection of hydride ions (SrH3-) was chosen owing to high beam intensity and low Coulomb explosion effects. 90Sr ions were identified and discriminated from isobaric 90Zr by measuring time of flight, total energy and three independent energy-loss signals in an ionization chamber. A reference sample and a ground-water sample were successfully measured. The detection limit determined for a laboratory blank by the residual counts in the 90Sr region is 90Sr/Sr = 3 ?? 10-13, corresponding in practice to (2-4) ?? 10790Sr atoms or about 0.5-1 pCi/L in environmental water samples.

Maxdose-SR and popdose-SR routine release atmospheric dose models used at SRS

Energy Technology Data Exchange (ETDEWEB)

Jannik, G. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Trimor, P. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-07-28

MAXDOSE-SR and POPDOSE-SR are used to calculate dose to the offsite Reference Person and to the surrounding Savannah River Site (SRS) population respectively following routine releases of atmospheric radioactivity. These models are currently accessed through the Dose Model Version 2014 graphical user interface (GUI). MAXDOSE-SR and POPDOSE-SR are personal computer (PC) versions of MAXIGASP and POPGASP, which both resided on the SRS IBM Mainframe. These two codes follow U.S. Nuclear Regulatory Commission (USNRC) Regulatory Guides 1.109 and 1.111 (1977a, 1977b). The basis for MAXDOSE-SR and POPDOSE-SR are USNRC developed codes XOQDOQ (Sagendorf et. al 1982) and GASPAR (Eckerman et. al 1980). Both of these codes have previously been verified for use at SRS (Simpkins 1999 and 2000). The revisions incorporated into MAXDOSE-SR and POPDOSE-SR Version 2014 (hereafter referred to as MAXDOSE-SR and POPDOSE-SR unless otherwise noted) were made per Computer Program Modification Tracker (CPMT) number Q-CMT-A-00016 (Appendix D). Version 2014 was verified for use at SRS in Dixon (2014).

Imaging and tuning polarity at SrTiO3 domain walls

Science.gov (United States)

Frenkel, Yiftach; Haham, Noam; Shperber, Yishai; Bell, Christopher; Xie, Yanwu; Chen, Zhuoyu; Hikita, Yasuyuki; Hwang, Harold Y.; Salje, Ekhard K. H.; Kalisky, Beena

2017-12-01

Electrostatic fields tune the ground state of interfaces between complex oxide materials. Electronic properties, such as conductivity and superconductivity, can be tuned and then used to create and control circuit elements and gate-defined devices. Here we show that naturally occurring twin boundaries, with properties that are different from their surrounding bulk, can tune the LaAlO3/SrTiO3 interface 2DEG at the nanoscale. In particular, SrTiO3 domain boundaries have the unusual distinction of remaining highly mobile down to low temperatures, and were recently suggested to be polar. Here we apply localized pressure to an individual SrTiO3 twin boundary and detect a change in LaAlO3/SrTiO3 interface current distribution. Our data directly confirm the existence of polarity at the twin boundaries, and demonstrate that they can serve as effective tunable gates. As the location of SrTiO3 domain walls can be controlled using external field stimuli, our findings suggest a novel approach to manipulate SrTiO3-based devices on the nanoscale.

Neodymium-doped Sr5(PO4)3F and Sr5(VO4)3F

International Nuclear Information System (INIS)

Corker, D.L.; Nicholls, J.; Loutts, G.B.

1995-01-01

Neodymium-doped Sr 5 (PO 4 ) 3 F [neodymium strontium fluoride phosphate, (Nd,Sr) 5 (PO 4 ) 3 F] and neodymium-doped Sr 5 (VO 4 ) 3 F [neodymium strontium fluoride vanadate, (Nd,Sr) 5 (VO 4 ) 3 F] crystallize in space group P6 3 /m and are isostructural with calcium fluorophosphate, Ca 5 (PO 4 ) 3 F. There are two different Sr sites in Sr 5 (XO 4 ) 3 F, denoted Sr(1) and Sr(2). Using single-crystal X-ray diffraction the two structures were refined to R factors of 2.3 and 2.2%, respectively, showing that Nd is present at both Sr sites in (Sr,Nd) 5 (VO 4 ) 3 F but only at the Sr(2) site in (Sr,Nd) 5 (PO 4 ) 3 F. (orig.)

Decoupling of unpolluted temperate forests from rock nutrient sources revealed by natural 87Sr/86Sr and 84Sr tracer addition

Science.gov (United States)

Kennedy, Martin J.; Hedin, Lars O.; Derry, Louis A.

2002-01-01

An experimental tracer addition of 84Sr to an unpolluted temperate forest site in southern Chile, as well as the natural variation of 87Sr/86Sr within plants and soils, indicates that mechanisms in shallow soil organic horizons are of key importance for retaining and recycling atmospheric cation inputs at scales of decades or less. The dominant tree species Nothofagus nitida feeds nearly exclusively (>90%) on cations of atmospheric origin, despite strong variations in tree size and location in the forest landscape. Our results illustrate that (i) unpolluted temperate forests can become nutritionally decoupled from deeper weathering processes, virtually functioning as atmospherically fed ecosystems, and (ii) base cation turnover times are considerably more rapid than previously recognized in the plant available pool of soil. These results challenge the prevalent paradigm that plants largely feed on rock-derived cations and have important implications for understanding sensitivity of forests to air pollution. PMID:12119394

The impact of Mg contents on Sr partitioning in benthic foraminifers

NARCIS (Netherlands)

Mewes, Antje; Langer, Gerald; Reichart, Gert Jan; de Nooijer, L.J.; Nehrke, Gernot; Bijma, Jelle

2015-01-01

Foraminiferal calcite Mg/Ca (Mg/CaCC) is used in paleoceanographic studies to reconstruct temperature. Furthermore, the Mg/CaCC is influenced by different seawater Mg/Ca (Mg/CaSW). Foraminiferal calcite Sr/Ca (Sr/CaCC) can potentially be used to reconstruct Sr/Ca ratios of seawater (Sr/CaSW). As

Experimental autoabsorption curve 90Sr in SrCO3. Efficiency calculation to detection of 90Sr, 90Y and 90Sr + 90Y in a beta gas proportional counter

International Nuclear Information System (INIS)

Gasco, C.; Alvarez, A.

1987-01-01

Strontium-90 has been determined by radiochemical separation techniques in environmental samples. These techniques, of course, cannot separate the two strontium radionuclides from each other of from stable strontium. Consequently the end product of the chemical separation contains all strontium isotopes in SrCO 3 . The beta particules emitted by 90 Sr are absorbed by the SrCO 3 precipitate. This is the main source of error in the activity measurement. It has been prepared sources of 90 Sr in SrCO 3 in order to determinate the counting efficiency and autoabsorption curve. Also detection efficiencies have been calibrated using known activities of 90 Y and equilibrium mixture of 90 Sr+ 90 Y in the same geometry than our samples. The activity of 90 Sr by ingrowth of 90 Y has been calculated by our computer program. (author). 2 figs., 3 refs

Contributions of conduction band offset to the enhanced separation efficiency of photoinduced charges for SrTiO3/Bi2O3 heterojunction semiconductor

International Nuclear Information System (INIS)

Zhang, Zhenlong; Zhu, Jichun; Li, Shengjun; Mao, Yanli

2014-01-01

SrTiO 3 /Bi 2 O 3 heterojunction semiconductor was prepared and characterized by X-ray diffraction, UV–vis absorption spectrum, and scanning electron microscope, surface photovoltage spectroscopy, and photoluminescence spectroscopy. The surface photovoltage spectra indicate that the separation efficiency of photoinduced charges for SrTiO 3 /Bi 2 O 3 was enhanced compared with that of SrTiO 3 or Bi 2 O 3 . The energy band diagram of SrTiO 3 /Bi 2 O 3 heterojunction was directly determined with X-ray photoelectron spectroscopy, and the conduction band offset between SrTiO 3 and Bi 2 O 3 was quantified to be 0.28±0.03 eV. The photoluminescence spectra display that the recombination rate of photoinduced carriers for SrTiO 3 /Bi 2 O 3 decreases compared with that of SrTiO 3 or Bi 2 O 3 , which is mainly due to the energy levels matching between them. Therefore the enhanced separation efficiency of photoinduced charges is resulting from the energy difference between the conduction band edges of SrTiO 3 and Bi 2 O 3 . -- Graphical abstract: Enhanced separation efficiency for SrTiO 3 /Bi 2 O 3 is resulting from the energy difference between the conduction band edges. Highlights: ●Heterojunction semiconductor of SrTiO 3 /Bi 2 O 3 was prepared. ●SrTiO 3 /Bi 2 O 3 presents enhanced separation efficiency. ●Conduction band offset between SrTiO 3 and Bi 2 O 3 is quantified. ●Recombination rate of SrTiO 3 /Bi 2 O 3 decreases compared with single phases

The Contribution of Health Technology Assessment, Health Needs Assessment, and Health Impact Assessment to the Assessment and Translation of Technologies in the Field of Public Health Genomics

DEFF Research Database (Denmark)

Rosenkotter, N.; Vondeling, H.; Blancquaert, I.

2011-01-01

contribute to the systematic translation and assessment of genomic health applications by focussing at population level and on public health policy making. It is shown to what extent HTA, HNA and HIA contribute to translational research by using the continuum of translational research (T1-T4) in genomic...... into the impact on public health and health care practice of those technologies that are actually introduced. This paper aims to give an overview of the major assessment instruments in public health [ health technology assessment (HTA), health needs assessment (HNA) and health impact assessment (HIA)] which could...... medicine as an analytic framework. The selected assessment methodologies predominantly cover 2 to 4 phases within the T1-T4 system. HTA delivers the most complete set of methodologies when assessing health applications. HNA can be used to prioritize areas where genomic health applications are needed...

Calcium-sensing receptor (CaSR): pharmacological properties and signaling pathways.

Science.gov (United States)

Conigrave, Arthur D; Ward, Donald T

2013-06-01

In this article we consider the mechanisms by which the calcium-sensing receptor (CaSR) induces its cellular responses via the control (activation or inhibition) of signaling pathways. We consider key features of CaSR-mediated signaling including its control of the heterotrimeric G-proteins Gq/11, Gi/o and G12/13 and the downstream consequences recognizing that very few CaSR-mediated cell phenomena have been fully described. We also consider the manner in which the CaSR contributes to the formation of specific signaling scaffolds via peptide recognition sequences in its intracellular C-terminal along with the origins of its high level of cooperativity, particularly for Ca(2+)o, and its remarkable resistance to desensitization. We also consider the nature of the mechanisms by which the CaSR controls oscillatory and sustained Ca(2+)i mobilizing responses and inhibits or elevates cyclic adenosine monophosphate (cAMP) levels dependent on the cellular and signaling context. Finally, we consider the diversity of the receptor's ligands, ligand binding sites and broader compartment-dependent physiological roles leading to the identification of pronounced ligand-biased signaling for agonists including Sr(2+) and modulators including l-amino acids and the clinically effective calcimimetic cinacalcet. We note the implications of these findings for the development of new designer drugs that might target the CaSR in pathophysiological contexts beyond those established for the treatment of disorders of calcium metabolism. Copyright © 2013 Elsevier Ltd. All rights reserved.

Quality control methods of strontium chloride 89SrCl2, radiopharmaceutical for palliative treatment of bone metastases

International Nuclear Information System (INIS)

Deptula, C.Z.; Kempisty, T.; Markiewicz, A.; Mikolajczak, R.; Stefancyk, S.; Terlikowska, T.; Zulczyk, W.

1997-01-01

Strontium chloride, 89 SrCI 2 , a radiopharmaceutical used for palliative therapy of bone metastases from breast and prostate cancer is produced by irradiation in a nuclear reactor. The analytical quality control procedures are established to confirm the radionuclidic purity of the preparation, its chemical composition and specific activity. Chemical concentration of strontium in the product is determined by complexometry with arsenazo III and chlorides assay by potentiometric titration with silver nitrate. The contamination with chemical impurities is determined by DC graphite spark spectrography. The specific activity and isotonicity of the solution are corrected by addition of natural SrCI 2 and NaCI. 90 Sr is produced in the 89 Sr(n,γ) 90 Sr reaction contributes to impurities. It decays to 90 Y and the activity of 90 Sr can be calculated from the activity of 90 Y. The extraction chromatography on nonionic acrylic ester polymer coated with organic solutions of selective features (Spec resins for Eichrom) is applied for separation of radionuclides. The extraction chromatography system consisting of two columns: strontium selective resin and rare earth elements selective resin was used for separation of 90 Y from 90 Sr in the 89 SrCI 2 solution. The 90 Y and 90 Sr carrier-free solutions used as tracers helped for determination of extraction conditions and efficiency. The concentration of 90 Sr determined in the analysed solution is at the level of 2.10 -4 % which conforms with the data calculated from irradiation parameters. The obtained product, strontium chloride 89 SrCI 2 for injection, forms a sterile and isotonic water solution (pH - 4-7) with specific activity of 89 Sr in the range from 3.5 to 6.3. MBq/mg and radioactive concentration of 37.5 MBq/ml. The radionuclidic purity of the obtained preparations is at the level of 99.9% with respect to 89 Sr

Mg- and/or Sr-doped tricalcium phosphate/bioactive glass composites: Synthesis, microstructure and biological responsiveness

Energy Technology Data Exchange (ETDEWEB)

Bellucci, Devis, E-mail: devis.bellucci@unimore.it [Department of Engineering “E. Ferrari”, University of Modena and Reggio Emilia, Via Vignolese 905, 41125 Modena (Italy); Sola, Antonella [Department of Engineering “E. Ferrari”, University of Modena and Reggio Emilia, Via Vignolese 905, 41125 Modena (Italy); Cacciotti, Ilaria [University of Rome " Niccolò Cusano" , UdR INSTM, Via Don Carlo Gnocchi 3, 00166, Rome (Italy); Bartoli, Cristina; Gazzarri, Matteo [Department of Chemistry and Industrial Chemistry, University of Pisa, UdR INSTM — Pisa, Via Risorgimento 35, 56127 Pisa (Italy); Bianco, Alessandra [Department of Enterprise Engineering, INSTM RU “Rome-Tor Vergata”, Via del Politecnico 1, 00133 Roma (Italy); Chiellini, Federica [Department of Chemistry and Industrial Chemistry, University of Pisa, UdR INSTM — Pisa, Via Risorgimento 35, 56127 Pisa (Italy); Cannillo, Valeria [Department of Engineering “E. Ferrari”, University of Modena and Reggio Emilia, Via Vignolese 905, 41125 Modena (Italy)

2014-09-01

Presently, there is an increasing interest towards the composites of calcium phosphates, especially β-tricalcium phosphate (TCP), and bioactive glasses. In the present contribution, the recently developed BG{sub C}a/Mix glass has been used because its low tendency to crystallize allows to sinter the composites at relatively low temperature (i.e. 850 °C), thus minimizing the glass devitrification and the interaction with TCP. A further improvement is the introduction of lab-produced TCP powders doped with specific ions instead of non-doped commercial powders, since the biological properties of materials for bone replacement can be modulated by doping them with certain metallic ions, such as Mg and Sr. Therefore, novel binary composites have been produced by sintering the BG{sub C}a/Mix glass with the addition of pure, Mg-substituted, Sr-substituted or Mg/Sr bisubstituted TCP powders. After an accurate characterization of the starting TCP powders and of the obtained samples, the composites have been used as three-dimensional supports for the culture of mouse calvaria-derived pre-osteoblastic cells. The samples supported cell adhesion and proliferation and induced promising mechanisms of differentiation towards an osteoblastic phenotype. In particular, the Mg/Sr bi-doped samples seemed to better promote the differentiation process thus suggesting a combined stimulatory effect of Mg{sup 2+} and Sr{sup 2+} ions.

Mg- and/or Sr-doped tricalcium phosphate/bioactive glass composites: Synthesis, microstructure and biological responsiveness

International Nuclear Information System (INIS)

Bellucci, Devis; Sola, Antonella; Niccolò Cusano, UdR INSTM, Via Don Carlo Gnocchi 3, 00166, Rome (Italy))" data-affiliation=" (University of Rome Niccolò Cusano, UdR INSTM, Via Don Carlo Gnocchi 3, 00166, Rome (Italy))" >Cacciotti, Ilaria; Bartoli, Cristina; Gazzarri, Matteo; Bianco, Alessandra; Chiellini, Federica; Cannillo, Valeria

2014-01-01

Presently, there is an increasing interest towards the composites of calcium phosphates, especially β-tricalcium phosphate (TCP), and bioactive glasses. In the present contribution, the recently developed BG C a/Mix glass has been used because its low tendency to crystallize allows to sinter the composites at relatively low temperature (i.e. 850 °C), thus minimizing the glass devitrification and the interaction with TCP. A further improvement is the introduction of lab-produced TCP powders doped with specific ions instead of non-doped commercial powders, since the biological properties of materials for bone replacement can be modulated by doping them with certain metallic ions, such as Mg and Sr. Therefore, novel binary composites have been produced by sintering the BG C a/Mix glass with the addition of pure, Mg-substituted, Sr-substituted or Mg/Sr bisubstituted TCP powders. After an accurate characterization of the starting TCP powders and of the obtained samples, the composites have been used as three-dimensional supports for the culture of mouse calvaria-derived pre-osteoblastic cells. The samples supported cell adhesion and proliferation and induced promising mechanisms of differentiation towards an osteoblastic phenotype. In particular, the Mg/Sr bi-doped samples seemed to better promote the differentiation process thus suggesting a combined stimulatory effect of Mg 2+ and Sr 2+ ions

Analysis of uncertainties and detection limits for the double measurement method of {sup 90}Sr and {sup 89}Sr

Energy Technology Data Exchange (ETDEWEB)

Herranz, M., E-mail: m.herranz@ehu.es [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda de Urquijo s/n 48013 Bilbao (Spain); Idoeta, R.; Legarda, F. [Department of Nuclear Engineering and Fluid Mechanics, University of the Basque Country (UPV/EHU), Alameda de Urquijo s/n 48013 Bilbao (Spain)

2011-08-15

The determination process of the {sup 90}Sr and {sup 89}Sr contents in a sample, although it involves their radiochemical isolation, results always in a complex measurement process due to the interferences among their respective beta emissions and also among those of the daughter of {sup 90}Sr, {sup 90}Y, a beta emitter as well. In this paper, the process consisting in a double measurement method after the Sr radiochemical isolation is analyzed, developing the formulae to obtain activity concentrations, uncertainties and detection limits. A study of the trend of uncertainties and detection limits as function of the time in which the first measurement since the isolation is done, the delay between the two measurements and the activity concentration of each strontium isotope in the sample is carried out as well. Results show that with a very precise determination of the times involved in the whole process (isolation, measurement and duration of measurements) this method permits a reliable assessment of both strontium radioisotopes. The quicker the first measurement since the isolation is done and the longer the delay between measurements is chosen, the lower are the detection limits and the uncertainties of the activities obtained. - Highlights: > The double measurement method for {sup 90}Sr and {sup 89}Sr determination is analysed. > Uncertainties and detection limits are determined and their dependences studied. > Proposals for the optimization of the method are given.

Preparation and characterization of Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite for bone repair application

Directory of Open Access Journals (Sweden)

Hossein Mohammadi

2015-07-01

Full Text Available Objective(s: Hardystonite (HT is Zn-modified silicate bioceramics with promising results for bone tissue regeneration. However, HT possesses no obvious apatite formation. Thus, in this study we incorporated Sr and Ti into HT to prepare Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite and evaluated its in vitro bioactivity with the purpose of developing a more bioactive bone substitute material. Materials and methods:The HT and Sr-Ti-HT were prepared by mechanical milling and subsequent heat treatment. Calcium oxide (CaO, zinc oxide (ZnO and silicon dioxide (SiO2 (all from Merck were mixed with molar ratio of 2:1:2. The mixture of powders mixture was then milled in a planetary ball mill for 20 h. In the milling run, the ball-to-powder weight ratio was 10:1 and the rotational speed was 200 rpm. After synthesis of HT, 3% nanotitanium dioxide (TiO2, Degussa and 3% strontium carbonate (SrCO3, Merck were added to HT and then the mixture was ball milled and calcined at 1150°C for 6 h. Simultaneous thermal analysis (STA, X-ray diffraction (XRD, Transmission electron microscopy (TEM and Fourier transform infra-red spectroscopy (FT-IR performed to characterize the powders. Results:XRD and FT-IR confirmed the crystal phase and silicate structure of HT and TEM images demonstrated the nanostructure of powders. Further, Sr-Ti-HT induced apatite formation and showed a higher human mesenchymal stem cell (hMSCs adhesion and proliferation compared to HT. Conclusion:Our study revealed that Sr-Ti-HT with a nanostructured crystal structure of 50 nm, can be prepared by mechanical activation to use as biomaterials for orthopedic applications.

Magnetic heat transport in Sr{sub 2}IrO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Steckel, Frank [Leibniz Institute for Solid State and Materials Research, IFW Dresden (Germany); Takagi, Hidenori [Max-Planck-Institute for Solid State Research, Stuttgart (Germany); Buechner, Bernd; Hess, Christian [Leibniz Institute for Solid State and Materials Research, IFW Dresden (Germany); Center for Transport and Devices, TU Dresden (Germany)

2015-07-01

The layered perovskite Sr{sub 2}IrO{sub 4} is a 5d transition metal oxide with an enhanced spin-orbit coupling leading to a Mott insulating ground state with J{sub eff}=(1)/(2). It exhibits canted antiferromagnetism below T{sub N}=240 K with an antiferromagnetic coupling constant of about J=0.1 eV. Thermal conductivity measurements along the ab plane of a Sr{sub 2}IrO{sub 4} single crystal provide evidence for a contribution of magnons (below T{sub N}) to the thermal conductivity, similar to that of the isostructural 2D S=(1)/(2) Heisenberg antiferromagnet La{sub 2}CuO{sub 4}, where a significant magnonic contribution to the heat transport is known.

Review of SKB's reporting of SR 97

International Nuclear Information System (INIS)

Tiren, S.A.

2000-01-01

The task of the safety assessment is to show 'that the repository has been designed with sufficient margins to be safe in spite of the incomplete knowledge available'. SKB mentions 'confidence in the results' as an important aspect. For the layman, confidence in the information presented is of the greatest importance. This means that the presentation of the safety assessment should be of a high visual standard with respect to descriptions of processes and events. SKB presented the purpose of SR 97 as four points. From a geological-structural geological viewpoint, the following can be mentioned: 1. Methodology for evaluating the geometry of the structural patterns of the bedrock at a depth of 500 m exists in general, but there are also certain deficiencies. Examples include determining the position of the individual structures and obtaining information. The importance of the bedrock is not completely clear. What is related to the rock type and what is related to the geological environment (including the geological evolution)? A clearer and more systematic compilation of data used in the safety assessment is required. 2. Work involving alternative models and evaluations of how well the models explain the collected data would be appropriate. The geological and structural models for a site are included as the base data in calculations and other modelling conducted in connection with the characterization of a site. 3. SR 97 does not provide any detailed information on site investigations. 4. The function of the bedrock as an external barrier is shown. However, to a certain extent, information on how this barrier can be affected by aseismic creep movements along fracture structures and the impact of selective erosion along such structures is lacking. Furthermore, criteria for properties of the rock volumes where deposition drifts are planned should be expanded, such as by determining a minimum width and suitable length-width relations

Emission of 89/90Sr in the waste air of nuclear power plants with LWR in West Germany

International Nuclear Information System (INIS)

Gesewsky, P.; Riedel, H.

1977-12-01

In particular the data of Sr-90 concentrations in the gaseous effluent are given for the years 1975 up to 1977 whereas the data for Sr-89 concentrations are given for the year 1977 only. The Sr is radiochemically separated after dissolution of the aerosol filters and Sr-89 and Sr-90 are measured by two countings on a low-level β-counter. (Single separation method). From this measurements the following average emissionrates, based on a power generation of 1 GWa were calculated: BWR's: 3,0 .(period on line) 10 -4 Ci Sr-89, 2,0 .(period on line) 10 -5 Ci Sr-90; PWR's: -6 Ci Sr-90, -5 Ci-Sr-89. In comparison to the emission of long-lived radioactive aerosols with the airborne effluent of light water cooled power reactors the Sr-90 contribution is clearly below 1% usually assumed in safety calculations. (orig./HP) [de

ACTH Regulation of Adrenal SR-B1

Directory of Open Access Journals (Sweden)

Wen-Jun eShen

2016-05-01

Full Text Available The adrenal gland is one of the prominent sites for steroid hormone synthesis. Lipoprotein-derived cholesterol esters delivered via scavenger receptor, class B type 1 (SR-B1 constitute the dominant source of cholesterol for steroidogenesis, particularly in rodents. ACTH stimulates steroidogenesis through downstream actions on multiple components involved in steroidogenesis. Both acute and chronic ACTH treatment can modulate SR-B1 function including its transcription, its post transcriptional stability, its phosphorylation and dimerization status, as well as its interaction with other protein partners; all of which result in changes in the ability of SR-B1 to mediate HDL-cholesterol ester uptake and the supply of cholesterol for conversion to steroids. Here we provide a review of the recent findings on the regulation of adrenal SR-B1 function by ACTH.

Environmental Assessment, SR 123 (Roger J. Clary Highway) from North of the Intersection of SR 123 and SR 85S to SR 85N, Okaloosa County, Eglin Air Force Base, Florida

Science.gov (United States)

2012-05-01

mph) SRS 123 / SR 85 Traffic Volumes Receptor Max 1-Hr CO Conc (ppm) Max 8-Hr CO Conc (ppm) AADT VPH Alternative 2 (East Shift) and...8.4 5.0 AADT: Annual Average Daily Traffic. VPH : Vehicles per Hour Environmental Consequences Air Quality Impacts

Mg and Sr in Arctic echinoderm calcite: Nature or nurture?

Science.gov (United States)

Iglikowska, A.; Borszcz, T.; Drewnik, A.; Grabowska, M.; Humphreys-Williams, E.; Kędra, M.; Krzemińska, M.; Piwoni-Piórewicz, A.; Kukliński, P.

2018-04-01

The Mg/Ca and Sr/Ca ratios in echinoderm skeletal calcite are used as a proxy for Phanerozoic seawater changes, since the skeletal concentrations are, to some extent, controlled by environmental factors. However, it remains unclear how the influence of environmental factors is modified by vital effects, especially in polar waters. Therefore, the goal of this study was to compare the ratios of Mg/Ca and Sr/Ca among the skeletal parts of 10 common Arctic echinoderm species belonging to three classes Echinoidea, Asteroidea and Ophiuroidea that contribute substantially to the carbon cycle in the Arctic benthic system. Significant differences were recorded in echinoid skeletal element concentrations among specific skeletal parts. The lowest Mg/Ca and Sr/Ca ratios were detected in the spines (mean Mg/Ca 37.5 ± 8.8 SD; Sr/Ca 1.8 ± 0.1). The components of the Aristotle's lantern (epiphyses, pyramids and rotulas) were characterised by the highest Mg levels (Mg/Ca 79.9 ± 6.0; 75.2 ± 9.1; 60.1 ± 3.8, respectively). It is likely that mouth parts experience greater mechanical pressure compared to other body parts, and the higher content of Mg in the Aristotle's lantern contributes to its robustness. We did not find any distinctive trends in the distribution of skeletal elements in the asteroid and ophiuroid skeletal parts. The heterogeneous concentrations of Mg and Sr in different skeleton parts of the echinoids suggest possible physiological regulation of the chemical composition rather than the composition only being influenced by the environment. We cannot recommend echinoderm skeletons as reliable indicators in palaeoenvironmental reconstructions due to the possible biological control of skeletal chemistry, which may interfere with the effect of environmental variables.

Trace-element and Sr-Nd isotopic evidence for the origin of the Sardinian fluorite mineralization (Italy)

International Nuclear Information System (INIS)

Castorina, F.; Masi, U.; Padalino, G.; Palomba, M.

2008-01-01

The fluorite-bearing hydrothermal mineralization in Sardinia mainly occurs within Paleozoic volcanic and metasedimentary rocks. Only 3 occurrences are located in volcanic and siliciclastic Cenozoic rocks. Most Sardinian fluorites exhibit relatively high rare earth and Y (REY) contents, strong positive Y anomalies, slightly negative Ce and generally positive Eu anomalies. These features indicate that the REY were mobilized mainly from non-carbonate rocks. Neither Sr nor Nd isotopes can be used to date radiometrically the Sardinian fluorites. However, the measured Sr-isotope ratios of the fluorites hosted by Paleozoic rocks fit mixing lines in the 1000/Sr versus 87 Sr/ 86 Sr plot once recalculated at 280 Ma, suggesting that the age inferred for the correction probably represents that of the formation of the fluorite mineralization. Mixing likely occurred between diluted surficial waters and brines circulating mainly through the Lower Paleozoic metasedimentary basement. The Cenozoic fluorites exhibit chemical and isotopic features similar to those of the Paleozoic fluorites, except the Nuraghe Onigu fluorite displaying a possible contribution of Sr from Cenozoic magmatic rocks. The initial ε Nd values of the Paleozoic fluorites fit the age proposed for the formation of the deposits. Moreover, the values suggest that radiogenic Nd was provided to the fluids from the Ordovician siliciclastic basement, except for 3 deposits where the potential source rocks of Nd were mainly Ordovician acidic magmatic rocks. The initial ε Nd values of the Cenozoic fluorites suggest a provenance of Nd essentially from the leaching of Variscan granitoids

Evolution of 137Cs and 90Sr content of the main foodstuff in Bucharest area after the Chernobyl accident

International Nuclear Information System (INIS)

Toader, M.; Vasilache, R.A.

1997-01-01

Soon after the Chernobyl accident, the radioactive cloud, carrying the nuclides released into the atmosphere, reached Romania and, due to the rainy weather, an important fallout occurred over the Romanian territory. The most important contaminants for Romania were I 131 , Cs 134 , Cs 137 and Sr 90 . As in many other countries, in the first days, I 131 had the main contribution to the irradiation dose released to the population. After its decay, and the decay of other short-lived radionuclides, Cs 137 and Sr 90 remained the most important contaminants. The principal route of intake for these two radionuclides is considered to be the ingestion of contaminated foods. To assess the radioactive burden of foods, a long term, large scale survey was initiated at the National Institute of Hygiene and Public Health (INISP). These results were then used to assess the doses committed to cesium and strontium intake and the excedentary cancer risk for the population from Bucharest area

Strain dependence of interfacial antiferromagnetic coupling in La0.7Sr0.3MnO3/SrRuO3 superlattices

Science.gov (United States)

Das, Sujit; Herklotz, Andreas; Pippel, Eckhard; Guo, Er-Jia; Rata, Diana; Dörr, Kathrin

2015-03-01

We have investigated the magnetic response of La0.7Sr0.3MnO3/SrRuO3 superlattices to biaxial in-plane strain applied in-situ. Superlattices grown on piezoelectric substrates of 0.72PbMg1/3Nb2/3O3-0.28PbTiO3(001) (PMN-PT) show strong antiferromagnetic coupling of the two ferromagnetic components. The coupling field of μ0HAF = 1.8 T is found to change by μ0 ΔHAF / Δɛ ~ -520 mT %-1 under reversible biaxial strain (Δɛ) at 80 K in a [La0.7Sr0.3MnO3(22 Å)/SrRuO3(55 Å)]15 superlattice. This reveals a significant strain effect on interfacial coupling. The applied in-plane compression enhances the ferromagnetic order in the manganite layers which are under as-grown tensile strain. It is thus difficult to disentangle the contributions from strain-dependent antiferromagnetic Mn-O-Ru interface coupling and Mn-O-Mn ferromagnetic double exchange near the interface, since the enhanced magnetic order of Mn spins leads to a larger net coupling of SrRuO3 layers at the interface. We discuss our experimental findings taken into account both the strain-dependent orbital occupation in a single-ion picture and the enhanced Mn order at the interface. This work was supported by the DFG within the Collaborative Research Center SFB 762 ``Functionality of Oxide Interfaces.''

Sr evolution in the Upper Permian and Lower Triassic carbonates, northeast Sichuan basin, China: Constraints from chemistry, isotope and fluid inclusions

International Nuclear Information System (INIS)

Li, Kaikai; Cai, Chunfang; Jiang, Lei; Cai, Liulu; Jia, Lianqi; Zhang, Bing; Xiang, Lei; Yuan, Yuyang

2012-01-01

Petrographic features, C, O and Sr isotopes, rare earth and trace elements were determined, and fluid inclusions were analyzed on various stages of interparticle cements and vug-fillings from the Upper Permian and Lower Triassic sour reservoirs in northeastern Sichuan basin. The aim was to assess the origin and evolution of palaeo-waters in the carbonates. The original water was contemporary seawater, from which marine cements precipitated with slightly high Sr contents (mean 1911 ppm), 87 Sr/ 86 Sr ratios from 0.7067 to 0.7082 and nonluminescent CL. The palaeo-seawater was diluted by meteoric water, as indicated by bright cathodoluminescence (CL) and Sr-depletion (0–516 ppm) in low-temperature calcite. When buried to temperatures of about 60–90 °C during Middle to Late Triassic, the palaeo-water was enriched in Sr released from the transformation of precursor aragonite and calcite to dolomite, resulting in precipitation of substantial pre-bitumen Sr-rich minerals (SrSO 4 and SrCO 3 ). For un-dolomitized limestone sections, aragonite neomorphism may have contributed Sr to the precipitation of small amounts of Sr-bearing minerals and calcite crystals with elevated homogenization temperatures (HTs, mainly from 90 to 130 °C) and wide Sr contents (from 34 to 3825 ppm), as recorded in stage III calcite. Since the Middle Jurassic, almost all of the early stage celestite and significant amounts of solid CaSO 4 have been consumed by reactions with hydrocarbons (i.e., TSR), resulting in water enriched in isotopically light CO 2 and HCO 3 - ,Sr 2+ ,Ba 2+ and Eu 2+ , as recorded in calcite with low δ 13 C values (down to −18.9‰), 87 Sr/ 86 Sr ratios from 0.7072 to 0.7076, high HTs (mainly 110–198 °C), positive Eu anomalies and high Sr and Ba contents. Subsequently, the water was uplifted and cooled down to about 115 °C, celestite and strontianite were precipitated with the occurrence of natural elemental S immiscible inclusions. TSR may have produced

Sr - an element shows the way - Applications of Sr isotopes for provenance, tracing and migration (Invited)

Science.gov (United States)

Prohaska, T.; Irrgeher, J.; Zitek, A.; Teschler Nicola, M.

2010-12-01

Strontium - named after the small Scottish town Strontian - as such is an element with little popularity. Firstly described by Martin Heinrich Klaproth in 1798, the metal is used in metallurgy to some extent whereas its compounds are interesting in glass industries, electronics and pyrotechnics. The element has chemical similarity to Ca and makes up 1/60 of the earth’s amount of the latter. Nonetheless, it is its isotopic composition which makes Sr so interesting for a large number of scientists. The natural composition of the four naturally occurring isotopes (84Sr, 86Sr 87Sr and 88Sr) varies in nature due to the radioactive decay of 87Rb to 87Sr. Thus, it was early recognized as geochronometer especially in Ca rich matrices. With increasing precision of applied methodology, the natural variation of the 87Sr/86Sr isotope ratio (analyzed at first mainly by thermal ionization mass spectrometry (TIMS)) became more and more popular in provenance studies. The natural variation of the ratio is mainly determined by the geological age and the original composition of the rock and can be used therefore as fingerprint of the local geology. The ratio is transferred with no significant fractionation via the water into plants and finally via the food chain into animal and human tissues (especially bones and teeth). As the element is chemically similar to Ca, it appears in most matrices. The use for provenance studies is supported by the fact that the long half life (4.8 x 1010 years) does not lead to an alteration during the time scales which are investigated (from recent samples to human or animal skeletal remains which date back up to 30.000 BC). The uniqueness of the system besides the natural variation is defined by the ubiquity in nature and the relatively high (and thus measurable) elemental concentration in most tissues. It was finally the advent of multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) which augmented the number of applications

SR-Can. Data and uncertainty assessment. Matrix diffusivity and porosity in situ

International Nuclear Information System (INIS)

Jinsong Liu; Loefgren, Martin; Neretnieks, Ivars

2006-12-01

and show beyond doubt that the electrical conductivity method using AC gives the expected information on transport properties (diffusivities) of the pores of crystalline rocks. The electrical conductivity method is much faster and can be used to measure large samples. It has recently been adopted for use in deep boreholes. Tens of thousands of measurements have been made at Simpevarp, Laxemar and Forsmark (Swedish sites) at depths of more than 1,000 m. The results of these measurements form the basis for our proposed diffusion values to be used in Performance Assessment (PA) for the candidate sites (Performance Assessment (PA) used in this report is synonymous to Safety Assessment (SA) sometimes used by other authors). The in situ data are obtained essentially in undisturbed rock and have not been subject to either stress release or disturbances due to sample preparation. The small disturbance nearest the borehole is negligible because the electrical conductivity method samples rock extending to more than a metre from the borehole. A large number of laboratory measurements have been analysed in order to ensure that other effects that cannot be controlled in the in situ measurements do not influence the down-hole data. No unexpected effects have been found. Rock matrix porosity in situ measurements are extremely scarce. However, it has been possible to use some of the in situ measurements to estimate the increase in porosity when taking up rock from its natural environment to the laboratory. One example of such an investigation is briefly discussed to show how this was done. In one in situ diffusion experiment performed at a depth of 60 m in granitic rock in Sweden the experimental conditions were such that it was ensured that any rock stress changes due to the presence of the drift and the presence of the borehole were avoided. The rock was thus subject to 'virgin stress'. Over-coring after exposure to tracers for three and a half years and detailed sampling and

SR-Can. Data and uncertainty assessment. Matrix diffusivity and porosity in situ

Energy Technology Data Exchange (ETDEWEB)

Jinsong Liu; Loefgren, Martin; Neretnieks, Ivars [Dept. of Chemical Engineering and Technology, Royal Inst. of Technology, Stockholm (Sweden)

2006-12-15

and show beyond doubt that the electrical conductivity method using AC gives the expected information on transport properties (diffusivities) of the pores of crystalline rocks. The electrical conductivity method is much faster and can be used to measure large samples. It has recently been adopted for use in deep boreholes. Tens of thousands of measurements have been made at Simpevarp, Laxemar and Forsmark (Swedish sites) at depths of more than 1,000 m. The results of these measurements form the basis for our proposed diffusion values to be used in Performance Assessment (PA) for the candidate sites (Performance Assessment (PA) used in this report is synonymous to Safety Assessment (SA) sometimes used by other authors). The in situ data are obtained essentially in undisturbed rock and have not been subject to either stress release or disturbances due to sample preparation. The small disturbance nearest the borehole is negligible because the electrical conductivity method samples rock extending to more than a metre from the borehole. A large number of laboratory measurements have been analysed in order to ensure that other effects that cannot be controlled in the in situ measurements do not influence the down-hole data. No unexpected effects have been found. Rock matrix porosity in situ measurements are extremely scarce. However, it has been possible to use some of the in situ measurements to estimate the increase in porosity when taking up rock from its natural environment to the laboratory. One example of such an investigation is briefly discussed to show how this was done. In one in situ diffusion experiment performed at a depth of 60 m in granitic rock in Sweden the experimental conditions were such that it was ensured that any rock stress changes due to the presence of the drift and the presence of the borehole were avoided. The rock was thus subject to 'virgin stress'. Over-coring after exposure to tracers for three and a half years and detailed sampling

An overview on the research of Sr2IrO4-based system probed by X-ray absorption spectroscopy

Science.gov (United States)

Cheng, Jie; Zhu, Chaomin; Ma, Jingyuan; Wang, Yu; Liu, Shengli

2018-03-01

Investigations of materials with 5d transition metal ions have opened up new paradigms in condensed-matter physics because of their large spin-orbit coupling (SOC) interactions. The typical compound is Sr2IrO4, which attracted much attention due to its similarities to the parent compound of high-Tc cuprate superconductor La2CuO4. Theoretical calculations predicted that the unconventional superconductivity can occur in carrier doped-Sr2IrO4 system. Until now, hundreds of experimental methods were devoted to investigate the carrier doping effect on Sr2IrO4. Synchrotron radiation-based X-ray absorption spectroscopy (XAS) made great contributions to the local lattice and electronic structure, and also the intimate relationship between the local structure and physical properties induced by carrier doping. The aim of this review is a short introduction to the progress of research on Sr2IrO4-based system probed by the unique technique — XAS, including the strength of the SOC, valence changes upon doping and even local lattice structure with atomic level for this Sr2IrO4-based family.

Environmental impact and risk assessments and key factors contributing to the overall uncertainties

International Nuclear Information System (INIS)

Salbu, Brit

2016-01-01

, ignoring sensitive history life stages of organisms and transgenerational effects. To link sources, ecosystem transfer and biological effects to future impact and risks, a series of models are usually interfaced, while uncertainty estimates are seldom given. The model predictions are, however, only valid within the boundaries of the overall uncertainties. Furthermore, the model predictions are only useful and relevant when uncertainties are estimated, communicated and understood. Among key factors contributing most to uncertainties, the present paper focuses especially on structure uncertainties (model bias or discrepancies) as aspects such as particle releases, ecosystem dynamics, mixed exposure, sensitive life history stages and transgenerational effects, are usually ignored in assessment models. Research focus on these aspects should significantly reduce the overall uncertainties in the impact and risk assessment of radioactive contaminated ecosystems. - Highlights: • Source term uncertainties: ignoring radionuclide speciation radioactive particles, the inventory can be underestimated. • Ecosystem transfer uncertainties: Ignoring time dependent interactions, transfer rates and pathways can be wrongly assessed. • Exposure uncertainties: ignoring stressor interactions and effects, effects cannot be judged. • Response uncertainties: ignoring sensitive stages transgenerational effects impact and risks can be underestimated.

Presentation of safety after closure of the repository for spent nuclear fuel. Main report of the project SR-Site. Part I; Redovisning av saekerhet efter foerslutning av slutfoervaret foer anvaent kaernbraensle. Huvudrapport fraan projekt SR-Site. Del I

Energy Technology Data Exchange (ETDEWEB)

2011-07-01

The purpose of the safety assessment SR-Site is to investigate whether a safe repository for spent nuclear fuel by KBS-3 type can be constructed at Forsmark in Oesthammar in Sweden. The location of the Forsmark has been selected based on results of several surveys from surface conditions at depth in Forsmark and in Laxemar in Oskarshamn. The choice of location is not justified in SR-Site Report, but in other attachments to SKB's permit applications. SR-Site Report is an important part of SKB's permit applications to construct and operate a repository for spent nuclear fuel at Forsmark in Oesthammar. The purpose of the report in the applications is to show that a repository at Forsmark is safe after closure

Presentation of safety after closure of the repository for spent nuclear fuel. Main report of the project SR-Site. Part II; Redovisning av saekerhet efter foerslutning av slutfoervaret foer anvaent kaernbraensle. Huvudrapport fraan projekt SR-Site. Del II

Energy Technology Data Exchange (ETDEWEB)

2011-07-01

The purpose of the safety assessment SR-Site is to investigate whether a safe repository for spent nuclear fuel by KBS-3 type can be constructed at Forsmark in Oesthammar in Sweden. The location of the Forsmark has been selected based on results of several surveys from surface conditions at depth in Forsmark and in Laxemar in Oskarshamn. The choice of location is not justified in SR-Site Report, but in other attachments to SKB's permit applications. SR-Site Report is an important part of SKB's permit applications to construct and operate a repository for spent nuclear fuel at Forsmark in Oesthammar. The purpose of the report in the applications is to show that a repository at Forsmark is safe after closure

Presentation of safety after closure of the repository for spent nuclear fuel. Main report of the project SR-Site. Part III; Redovisning av saekerhet efter foerslutning av slutfoervaret foer anvaent kaernbraensle. Huvudrapport fraan projekt SR-Site. Del III

Energy Technology Data Exchange (ETDEWEB)

2011-07-01

The purpose of the safety assessment SR-Site is to investigate whether a safe repository for spent nuclear fuel by KBS-3 type can be constructed at Forsmark in Oesthammar in Sweden. The location of the Forsmark has been selected based on results of several surveys from surface conditions at depth in Forsmark and in Laxemar in Oskarshamn. The choice of location is not justified in SR-Site Report, but in other attachments to SKB's permit applications. SR-Site Report is an important part of SKB's permit applications to construct and operate a repository for spent nuclear fuel at Forsmark in Oesthammar. The purpose of the report in the applications is to show that a repository at Forsmark is safe after closure

AMBER and Ecolego Intercomparisons using Calculations from SR 97

International Nuclear Information System (INIS)

Maul, Philip; Robinson, Peter; Avila, Rodolfo; Broed, Robert; Pereira, Antonio

2003-08-01

. The residual differences in the other calculations are due to small differences in the interpretation of the SR 97 models and data. 3. The results of the deterministic calculations for the geosphere, where AMBER used a compartment model and Ecolego a one-dimensional contaminant transport model, were also generally in agreement to within one significant figure, except where radionuclides fluxes are very low (e.g., for 239 Pu), where the compartmental approximation in AMBER can overestimate the output flux. 4. In several instances the SR 97 documentation was not sufficiently clear to enable the implementation of the models in AMBER and Ecolego to be unambiguous. Examples include the structure of the coastal biosphere model and the algorithms used in some of the dose calculations. 5. Some key issues for the SR 97 assessment have been identified; these provide an indication of where detailed scrutiny will be required of any safety case made by SKB for a deep repository

Anisotropic magnetoresistance and spin polarization of La0.7Sr0.3MnO3/SrTiO3 superlattices

International Nuclear Information System (INIS)

Wang, L.M.; Guo, C.-C.

2005-01-01

The crystalline structure, anisotropic magnetoresistance (AMR), and magnetization of La 0.7 Sr 0.3 MnO 3 /SrTiO 3 (LSMO/STO) superlattices grown by a rf sputtering system are systematically analyzed to study the spin polarization of manganite at interfaces. The presence of positive low-temperature AMR in LSMO/STO superlattices implies that two bands of majority and minority character contribute to the transport properties, leading to a reduced spin polarization. Furthermore, the magnetization of superlattices follows the T 3/2 law and decays more quickly as the thickness ratio d STO /d LSMO increases, corresponding to a reduced exchange coupling. The results clearly show that the spin polarization is strongly correlated with the influence of interface-induced strain on the structure

Seasonal and episodic moisture controls on plant and microbial contributions to soil respiration.

Science.gov (United States)

Carbone, Mariah S; Still, Christopher J; Ambrose, Anthony R; Dawson, Todd E; Williams, A Park; Boot, Claudia M; Schaeffer, Sean M; Schimel, Joshua P

2011-09-01

Moisture inputs drive soil respiration (SR) dynamics in semi-arid and arid ecosystems. However, determining the contributions of root and microbial respiration to SR, and their separate temporal responses to periodic drought and water pulses, remains poorly understood. This study was conducted in a pine forest ecosystem with a Mediterranean-type climate that receives seasonally varying precipitation inputs from both rainfall (in the winter) and fog-drip (primarily in the summer). We used automated SR measurements, radiocarbon SR source partitioning, and a water addition experiment to understand how SR, and its separate root and microbial sources, respond to seasonal and episodic changes in moisture. Seasonal changes in SR were driven by surface soil water content and large changes in root respiration contributions. Superimposed on these seasonal patterns were episodic pulses of precipitation that determined the short-term SR patterns. Warm season precipitation pulses derived from fog-drip, and rainfall following extended dry periods, stimulated the largest SR responses. Microbial respiration dominated these SR responses, increasing within hours, whereas root respiration responded more slowly over days. We conclude that root and microbial respiration sources respond differently in timing and magnitude to both seasonal and episodic moisture inputs. These findings have important implications for the mechanistic representation of SR in models and the response of dry ecosystems to changes in precipitation patterns.

Experiment data report for semiscale Mod-2A primary feed and bleed experiment series (Tests S-SR-1 and S-SR-2)

International Nuclear Information System (INIS)

Fogdall, S.P.

1982-10-01

This report presents test data recorded for Tests S-SR-1 and S-SR-2 of the Semiscale Mod-2A Primary Feed and Bleed Tests. These tests are part of a series of Semiscale tests that investigate the thermal-hydraulic phenomena resulting from a hypothesized loss-of-coolant accident (LOCA) or abnormal operating transient. These tests provide experimental data for assessing the analytical capability of computer codes used in LOCA and operational transient analysis. The primary objectives of Tests S-SR-1 and -2 were to provide data on primary system recovery through the use of primary feed and bleed cooling, with no heat transfer to the secondaries. Data was obtained using high- and low-head pump curves for the safety injection (SI) pumps. This report presents the uninterpreted data from Tests S-SR-1 and -2 for analysis. The data, presented as graphs in engineering units, have been analyzed only to the extent necessary to ensure that they are reasonable and consistent

Geochronological synthesis of Bahia state and the crustal evolution, based in evolution diagram of Sr and initial rate of Sr87/Sr86

International Nuclear Information System (INIS)

Sato, K.

1986-01-01

The crustal evolution of the ancient terrains of the State of Bahia, Brazil, is attempted with the aid of Sr isotopic results as natural tracers. Some Nd and Pb isotopic data are also available, and support the main conclusions based on Sr evolution diagrams. The analysis of the Sr evolution diagrams shows that the Archean Terrains are mainly formed by accretion from mantle-derived material, but crustal reworking is indicated by the high initial 87 Sr/ 86 Sr value of the Jequie Complex. The Transamazonian mobile belt include both types of materials, but the 87 Sr/ 86 Sr value, generally lower than those of the Jequie Complex, markes improbable a direct derivation. During Middle and Late Proterozoic, the continental crust was already well consolidated, and reworking of crustal material predominated within the Espinhaco and Brasiliano folded systems [pt

SR-71 Pilot Stephen (Steve) D. Ishmael

Science.gov (United States)

1992-01-01

NASA research pilot Stephen D. Ishmael is pictured here in front of an SR-71 Blackbird on the ramp at the Dryden Flight Research Center, Edwards, California. Ishmael was one of two NASA research pilots assigned to the SR-71 high speed research program in the early 1990s at NASA's Dryden Flight Research Facility (redesignated the Dryden Flight Research Center in 1994), Edwards, California. Ishmael became a NASA research pilot in 1977. Data from the SR-71 program will be used to aid designers of future supersonic aircraft and propulsion systems. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and

Contribution of continuous assessment to student learning in ...

African Journals Online (AJOL)

The study seeks to find out whether continuous assessment contributes to students' performance mathematics. The objectives of this study were to find out whether; Students see continuous assessment as a motivating factor in their learning, there is any workload involved in filling of continuous assessment termly, ...

Physicochemical compatibility of SrCeO3 with potential SOFC cathodes

International Nuclear Information System (INIS)

Tolchard, J.; Grande, T.

2007-01-01

The chemical and physical compatibility of SrCeO 3 is investigated with respect to LaMO 3 (M=Mn, Fe, Co) and La 2-x Sr x NiO 4 (x=0, 0.8), via the reaction of fine-grained powder compacts and solid-state diffusion couples. Compositions were chosen so as to give predictive insight into possible candidate materials for all-oxide electrochemical devices. Results show the primary reaction in these systems to be the dissolution of SrO from SrCeO 3 into the LaMO 3 /La 2-x Sr x NiO 4 , and corresponding formation of La-doped CeO 2 . Reaction kinetics are observed to be relatively fast, with element profiles suggesting the diffusion of Sr 2+ in ceria to be surprisingly rapid. It is demonstrated that perovskite starting materials represent poor candidates for use with SrCeO 3 , reacting completely to form Ruddlesden-Popper/K 2 NiF 4 type oxides. Reaction with La 2 NiO 4 is less pronounced, and formation of secondary phases suppressed for the composition La 1.2 Sr 0.8 NiO 4 . It is thus concluded that Ruddlesden-Popper type oxides represent good candidate materials for use with a SrCeO 3 -based electrolytes when doped with appropriate levels of Sr. - Graphical abstract: Assessment of the SrCeO 3 proton conductor shows this material to have poor chemical compatibility with LaMO 3 perovskite systems, but predicts coexistence with Ruddlesden-Popper type oxides

Tracing subduction zone fluid-rock interactions using trace element and Mg-Sr-Nd isotopes

Science.gov (United States)

Wang, Shui-Jiong; Teng, Fang-Zhen; Li, Shu-Guang; Zhang, Li-Fei; Du, Jin-Xue; He, Yong-Sheng; Niu, Yaoling

2017-10-01

Slab-derived fluids play a key role in mass transfer and elemental/isotopic exchanges in subduction zones. The exhumation of deeply subducted crust is achieved via a subduction channel where fluids from various sources are abundant, and thus the chemical/isotopic compositions of these rocks could have been modified by subduction-zone fluid-rock interactions. Here, we investigate the Mg isotopic systematics of eclogites from southwestern Tianshan, in conjunction with major/trace element and Sr-Nd isotopes, to characterize the source and nature of fluids and to decipher how fluid-rock interactions in subduction channel might influence the Mg isotopic systematics of exhumed eclogites. The eclogites have high LILEs (especially Ba) and Pb, high initial 87Sr/86Sr (up to 0.7117; higher than that of coeval seawater), and varying Ni and Co (mostly lower than those of oceanic basalts), suggesting that these eclogites have interacted with metamorphic fluids mainly released from subducted sediments, with minor contributions from altered oceanic crust or altered abyssal peridotites. The positive correlation between 87Sr/86Sr and Pb* (an index of Pb enrichment; Pb* = 2*PbN/[CeN + PrN]), and the decoupling relationships and bidirectional patterns in 87Sr/86Sr-Rb/Sr, Pb*-Rb/Sr and Pb*-Ba/Pb spaces imply the presence of two compositionally different components for the fluids: one enriched in LILEs, and the other enriched in Pb and 87Sr/86Sr. The systematically heavier Mg isotopic compositions (δ26Mg = - 0.37 to + 0.26) relative to oceanic basalts (- 0.25 ± 0.07) and the roughly negative correlation of δ26Mg with MgO for the southwestern Tianshan eclogites, cannot be explained by inheritance of Mg isotopic signatures from ancient seafloor alteration or prograde metamorphism. Instead, the signatures are most likely produced by fluid-rock interactions during the exhumation of eclogites. The high Rb/Sr and Ba/Pb but low Pb* eclogites generally have high bulk-rock δ26Mg values

Uncertainty and Detection Limit in Determination of 89,90Sr by Cherenkov Counting

International Nuclear Information System (INIS)

Grahek, Z.; Karanovic, G.; Nodilo, M.

2013-01-01

The methodology for the rapid determination of 89,90Sr in normal and emergency situations is given. Methodology is based on simultaneous separation of strontium and yttrium from samples and quantitative 89,90Sr determination by Cherenkov counting within three days. Methodology for quantitative determination by Cherenkov counting based on following changes of sample activity during the time is described and discussed. It has been shown that 89,90Sr can be determined with acceptable accuracy when 89Sr/90Sr ratio is over 10:1. Obtained results show that by using low level liquid scintillation counter it can be possible to determine 89Sr and 90Sr in broad range of concentration activities (1 - 1000 Bq (kgL) -1 ) with uncertainties below 10% within 2-3 days. Results also show that accuracy of determination of 89Sr (and 90Sr) depends on determination of difference between separation and counting time when activity ratio of 89Sr/90Sr is high. Analysis of combined uncertainty shows that it mainly depends on uncertainty of efficiency and recovery determination, uncertainty of activities determination for both isotopes and level of background radiation. Portion of each in combined uncertainty depend on level of activity of each isotope and its activity ratio.(author)

Biosphere analyses for the safety assessment SR-Site - synthesis and summary of results

Energy Technology Data Exchange (ETDEWEB)

Saetre, Peter [comp.

2010-12-15

This report summarises nearly 20 biosphere reports and gives a synthesis of the work performed within the SR-Site Biosphere project, i.e. the biosphere part of SR-Site. SR-Site Biosphere provides the main project with dose conversion factors (LDFs), given a unit release rate, for calculation of human doses under different release scenarios, and assesses if a potential release from the repository would have detrimental effects on the environment. The intention of this report is to give sufficient details for an overview of methods, results and major conclusions, with references to the biosphere reports where methods, data and results are presented and discussed in detail. The philosophy of the biosphere assessment was to make estimations of the radiological risk for humans and the environment as realistic as possible, based on the knowledge of present-day conditions at Forsmark and the past and expected future development of the site. This was achieved by using the best available knowledge, understanding and data from extensive site investigations from two sites. When sufficient information was not available, uncertainties were handled cautiously. A systematic identification and evaluation of features and processes that affect transport and accumulation of radionuclides at the site was conducted, and the results were summarised in an interaction matrix. Data and understanding from the site investigation was an integral part of this work, the interaction matrix underpinned the development of the radionuclide model used in the biosphere assessment. Understanding of the marine, lake and river and terrestrial ecosystems at the site was summarized in a conceptual model, and relevant features and process have been characterized to capture site specific parameter values. Detailed investigations of the structure and history of the regolith at the site and simulations of regolith dynamics were used to describe the present day state at Forsmark and the expected development of

Synthesis and microstructural characterization of Sr- and Mg-substituted LaGaO3 solid electrolyte

International Nuclear Information System (INIS)

Datta, Pradyot; Majewski, Peter; Aldinger, Fritz

2007-01-01

Sr and Mg substituted LaGaO 3 is a solid electrolyte for intermediate temperature solid oxide fuel cell. Phase purity of this material is a concern for the researchers for a long time. In this contribution the secondary phases that are evolved during the synthesis of Sr and Mg doped LaGaO 3 are reported. For that purpose, a series of La 1-x Sr x Ga 1-y Mg y O 3-δ (LSGM) was prepared by solid state synthesis route. Scanning electron microscopic photographs showed secondary phases namely La 4 Ga 2 O 9 , LaSrGa 3 O 7 , LaSrGaO 4 along with the parent perovskite LSGM depending upon the amount of dopant. Amount of secondary phases was estimated from the peak positions of room temperature X-ray diffraction. It was observed that for a fixed amount of Mg dopant increasing the amount of Sr content also increased the amount of secondary phases whereas the reverse was found to be true when Sr content was fixed and Mg content was increased. This behaviour was attributed to the increase in solid solubility of Sr in presence of Mg

Preferred Orientation Contribution to the Anisotropic Normal State Resistivity in Superconducting Melt-Cast Processed Bi2Sr2CaCu2O8+δ

Directory of Open Access Journals (Sweden)

Aline Dellicour

2017-05-01

Full Text Available We describe how the contribution of crystallographic texture to the anisotropy of the resistivity of polycrystalline samples can be estimated by averaging over crystallographic orientations through a geometric mean approach. The calculation takes into account the orientation distribution refined from neutron diffraction data and literature values for the single crystal resistivity tensor. The example discussed here is a melt-cast processed Bi2Sr2CaCu2O8+δ (Bi-2212 polycrystalline tube in which the main texture component is a <010> fiber texture with relatively low texture strength. Experimentally-measured resistivities along the longitudinal, radial, and tangential directions of the Bi-2212 tube were compared to calculated values and found to be of the same order of magnitude. Calculations for this example and additional simulations for various texture strengths and single crystal resistivity anisotropies confirm that in the case of highly anisotropic phases such as Bi-2212, even low texture strengths have a significant effect on the anisotropy of the resistivity in polycrystalline samples.

A 3S Risk ?3SR? Assessment Approach for Nuclear Power: Safety Security and Safeguards.

Energy Technology Data Exchange (ETDEWEB)

Forrest, Robert; Reinhardt, Jason Christian; Wheeler, Timothy A.; Williams, Adam David

2017-11-01

Safety-focused risk analysis and assessment approaches struggle to adequately include malicious, deliberate acts against the nuclear power industry's fissile and waste material, infrastructure, and facilities. Further, existing methods do not adequately address non- proliferation issues. Treating safety, security, and safeguards concerns independently is inefficient because, at best, it may not take explicit advantage of measures that provide benefits against multiple risk domains, and, at worst, it may lead to implementations that increase overall risk due to incompatibilities. What is needed is an integrated safety, security and safeguards risk (or "3SR") framework for describing and assessing nuclear power risks that can enable direct trade-offs and interactions in order to inform risk management processes -- a potential paradigm shift in risk analysis and management. These proceedings of the Sandia ePRA Workshop (held August 22-23, 2017) are an attempt to begin the discussions and deliberations to extend and augment safety focused risk assessment approaches to include security concerns and begin moving towards a 3S Risk approach. Safeguards concerns were not included in this initial workshop and are left to future efforts. This workshop focused on four themes in order to begin building out a the safety and security portions of the 3S Risk toolkit: 1. Historical Approaches and Tools 2. Current Challenges 3. Modern Approaches 4. Paths Forward and Next Steps This report is organized along the four areas described above, and concludes with a summary of key points. 2 Contact: rforres@sandia.gov; +1 (925) 294-2728

High-pressure modifications of CaZn2, SrZn2, SrAl2, and BaAl2: Implications for Laves phase structural trends

International Nuclear Information System (INIS)

Kal, Subhadeep; Stoyanov, Emil; Belieres, Jean-Philippe; Groy, Thomas L.; Norrestam, Rolf; Haeussermann, Ulrich

2008-01-01

High-pressure forms of intermetallic compounds with the composition CaZn 2 , SrZn 2 , SrAl 2 , and BaAl 2 were synthesized from CeCu 2 -type precursors (CaZn 2 , SrZn 2 , SrAl 2 ) and Ba 21 Al 40 by multi-anvil techniques and investigated by X-ray powder diffraction (SrAl 2 and BaAl 2 ), X-ray single-crystal diffraction (CaZn 2 ), and electron microscopy (SrZn 2 ). Their structures correspond to that of Laves phases. Whereas the dialuminides crystallize in the cubic MgCu 2 (C15) structure, the dizincides adopt the hexagonal MgZn 2 (C14) structure. This trend is in agreement with the structural relationship displayed by sp bonded Laves phase systems at ambient conditions. - Graphical abstract: CeCu 2 -type polar intermetallics can be transformed to Laves phases upon simultaneous application of pressure and temperature. The observed structures are controlled by the valence electron concentration

Internal bremsstrahlung from 89Sr and 90Sr

International Nuclear Information System (INIS)

Sayibaba, T.; Narasimha Murity, K.; Rao, C.R.; Satyaprakash; Gubbi, G.K.

1987-01-01

The internal bremsstrahlung (IB) spectra emitted in the beta-decays of 89 Sr and 90 Sr were measured with a HPGe detector and a multichannel analyser along with a standard geometrical set-up. Sufficient care has been taken to avoid spurious effects. After making all the necessary corrections, the experimental results were compared with the corresponding theoretical distributions due to Knipp and Uhlenbeck and Bloch (KUB), Lewis and Ford, Nilsson, and also due to Ford and Martin (detour theory). The total IB yields of intensity and energy from each of the isotopes in the investigated energy regions are also determined and compared with the corresponding theoretical values. The present results of IB from 89 Sr are satisfactorily accounted for by the KUB theory. In the case of 90 Sr the experimental results of IB coincide with the Coulomb-corrected theoretical distibution due to Nilsson in the energy range from 60 keV to 110 keV and Beyond 110 keV, they are found to be in excess over Nilsson's theory as well as the detour theory due to Ford and Martin up to the maximum photon energy studied, namely 350 keV

Real-time {sup 90}Sr Counter

Energy Technology Data Exchange (ETDEWEB)

Kaneko, Naomi; Kawai, Hideyuki; Kodama, Satoshi; Kobayashi, Atsushi; Tabata, Makoto; Ito, Hiroshi [Graduate School of Science, Chiba University, Chiba, (Japan); Han, Soorim [Graduate School of Science, Chiba University, Chiba, (Japan); National Institute of Radiological Science, Chiba, (Japan)

2015-07-01

Radioisotopes have been emitted around Japan due to a nuclear accident at the Fukushima Daiichi nuclear power station in March 2011. A problem is the contaminated water including the atomic nucleus which relatively has a long half- life time and soluble such as {sup 90}Sr, {sup 137}Cs. Internal exposures by {sup 90}Sr are more dangerous than {sup 137}Cs's because Sr has effective half-life time of 18 years and property of accumulation in a born. We have developed real-time {sup 90}Sr counter which is sensitive beta-ray of maximum kinematic energy of 2.28 MeV from {sup 90}Sr and insensitive of beta-ray of maximum kinematic energy of 1.17 MeV and gamma-ray from {sup 90}Sr by Cherenkov detection. This counter composes of Cerenkov counter, trigger scintillation counter and veto counter. Silica aerogel for Cherenkov counter can obtain refractive index between 1.017 and 1.049 easily. And wavelength shifting fiber (WLSF) is used as a light guide for extending effective area and producing lower cost. A mechanism of the identification of {sup 90}Sr is explained in following. In case of {sup 90}Sr, when the trigger counter reacts on the beta-ray from {sup 90}Sr, aerogel emits the Cherenkov light and WLSF reacts and read the Cherenkov light. On the other hand, in case of {sup 137}Cs, the trigger counter reacts on the beta-ray, aerogel stops the beta- ray and Cherenkov light is not emitted. Therefore, aerogel has a function as a radiator and shielding material. the gamma-ray is not reacted on the lower density detector. Cosmic rays would be also reacted by the veto counter. A prototype counter whose the effective area is 30 cm x 10 cm was obtained (2.0±1.2){sup 3} of mis-identification as {sup 137}Cs/{sup 90}Sr. Detection limit in the surface contamination inspection depends on measurement time and effective area mainly. The sensitivity of wide range, 10{sup -2} - 10{sup 4} Bq/cm{sup 2}, is obtained by adjustment of detection level in circuit of this counter. A lower

Effect of Sr/Ti Ratio on the Photocatalytic Properties of SrTiO3

International Nuclear Information System (INIS)

Sulaeman, U; Yin, S; Sato, T

2011-01-01

Since strontium titanate is a wide gap semiconductor, it requires UV light to generate the photocatalytic activities. Modification of strontium titanate to show photocatalytic activity under visible light irradiation is the essential work to efficiently utilize the sun light energy for environmental application. It is expected that the synthesis of SrTiO 3 with variation of Sr/Ti atomic ratio could induce the defect crystals having unique photocatalytic properties. The SrTiO 3 with various Sr/Ti atomic ratios were synthesized by microwave-assisted solvothermal reaction of SrCl 2 .6H 2 O and Ti(OC 3 H 7 ) 4 in KOH aqueous solutions with different atomic ratios of Sr/Ti. The products were characterized by TG-DTA, XRD and DRS. The photocatalytic activity was determined by DeNO x ability using LED lamps with the wavelengths of 627 nm (red), 530 nm (green), 445 nm (blue) and 390 nm (UV). The nanoparticles of perovskite type SrTiO 3 with the particle size of 30-40 nm were successfully synthesized. The visible light responsive photocatalytic activity was generated by adding excess amount of Sr. The photocatalytic activity in visible light could be enhanced by an increase in the Sr/Ti atomic ratio up to 1.25, indicating that the visible light responsive photocatalytic activity is due to the generation of new band gap between the conduction band and valence band of SrTiO 3 by the formation of oxygen vacancy.

Gibbs energy formation of Sr5Nb4O15

International Nuclear Information System (INIS)

Samui, Pradeep; Padhi, Anyuna; Agarwal, Renu; Kulkarni, S.G.

2012-01-01

Ternary oxides of strontium and niobium may form as fission product compounds in an operating nuclear reactor with oxide fuels under certain oxygen potential. Evaluations of thermodynamic stability of these ternary oxides are therefore important for assessment of fission product interactions. Furthermore, thermodynamic data of these oxides are also of relevance because of computation of phase diagram and phase stability of pseudo-ternary systems BaO-SrO-Nb 2 O 5 , SrO-Nb 2 O 5 -TaO 5 etc. in which some of the compounds are potential candidate materials for microwave ceramics with high dielectric constant, electro-optic, pyroelectric and piezoelectric devices. The system Sr-Nb-O contains many ternary oxides out of which we have investigated the thermodynamic parameters for the compound Sr 5 Nb 4 O 15 in the present study

Robust half-metallicity of hexagonal SrNiO_3

International Nuclear Information System (INIS)

Chen, Gao-Yuan; Ma, Chun-Lan; Chen, Da; Zhu, Yan

2016-01-01

In the rich panorama of the electronic and magnetic properties of 3d transition metal oxides SrMO_3 (M=Ti, V, Cr, Mn, Fe, Co, Ni, Cu), one member (SrNiO_3) is missing. In this paper we use GGA+U method based on density functional theory to examine its properties. It is found that SrNiO_3 is a ferromagnetic half-metal. The charge density map shows a high degree of ionic bonding between Sr and other atoms. Meanwhile, a covalent-bonding Ni–O–Ni–O–Ni chain is observed. The spin density contour of SrNiO_3 further indicates that the magnetic interaction between Ni atoms mediated by O is semicovalent exchange. The density of states are examined to explore the unusual indirect magnetic-exchange mechanism. Corresponding to the total energies results, a robust half-metallic character is observed, suggesting a promising giant magneto-optical Kerr property of the material. The partial density of states are further examined to explore the origin of ferromagnetic half-metallicity. The O atoms are observed to have larger contribution at fermi level than Ni atoms to the spin-polarized states, demonstrating that O atoms play a critical role in ferromagnetic half-metallicity of SrNiO_3. Hydrostatic pressure effect is examined to evaluate how robust the half-metallic ferromagnetism is. - Graphical abstract: (a) The total energy as a function of the lattice constant a for hexagonal SrNiO3 with various magnetic phases. (b) The total electronic density of states for hexagonal SrNiO_3 with FM configuration from GGA+U calculations. (c) Total electron-density distribution in the (110) plane. The colors gradually change from cyan (through pink) to yellow corresponding to charge density value from 0 to 4.0. (d) The magnetization density map in the (110) plane. The colors range from blue (through green) to red corresponding to magnetization density value from −0.15 to 0.45. Black and white contours stand for positive and negative values, respectively. - Highlights: • Hexagonal Sr

OpenSR: An Open-Source Stimulus-Response Testing Framework

Directory of Open Access Journals (Sweden)

Carolyn C. Matheus

2015-01-01

Full Text Available Stimulus–response (S–R tests provide a unique way to acquire information about human perception by capturing automatic responses to stimuli and attentional processes. This paper presents OpenSR, a user-centered S–R testing framework providing a graphical user interface that can be used by researchers to customize, administer, and manage one type of S–R test, the implicit association test. OpenSR provides an extensible open-source Web-based framework that is platform independent and can be implemented on most computers using any operating system. In addition, it provides capabilities for automatically generating and assigning participant identifications, assigning participants to different condition groups, tracking responses, and facilitating collecting and exporting of data. The Web technologies and languages used in creating the OpenSR framework are discussed, namely, HTML5, CSS3, JavaScript, jQuery, Twitter Bootstrap, Python, and Django. OpenSR is available for free download.

SR 97 - Identification and structuring of process

International Nuclear Information System (INIS)

Pers, K.; Skagius, K.; Soedergren, S.; Wiborgh, M.; Hedin, A.; Moren, L.; Sellin, P.; Stroem, A.; Pusch, R.; Bruno, J.

1999-12-01

This report documents work conducted in recent years to identify processes and interactions of importance to the evaluation of long-term safety of a KBS 3 type deep repository for spent nuclear fuel. Previous, partly undocumented work regarding interaction matrices is described as well as the THMC diagrams that have been used in the safety assessment SR 97. The coupling between the two sources of information is documented in a database. In the same database, the interaction matrices are briefly documented, while the processes in the THMC diagrams are more thoroughly documented in a special so called Process Report, which forms an important supporting document for SR 97

SR 97 - Identification and structuring of process

Energy Technology Data Exchange (ETDEWEB)

Pers, K.; Skagius, K.; Soedergren, S.; Wiborgh, M. [Kemakta Konsult AB, Stockholm (Sweden); Hedin, A.; Moren, L.; Sellin, P.; Stroem, A. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Pusch, R. [Geodevelopment AB, Lund (Sweden); Bruno, J. [QuantiSci SL, Barcelona (Spain)

1999-12-01

This report documents work conducted in recent years to identify processes and interactions of importance to the evaluation of long-term safety of a KBS 3 type deep repository for spent nuclear fuel. Previous, partly undocumented work regarding interaction matrices is described as well as the THMC diagrams that have been used in the safety assessment SR 97. The coupling between the two sources of information is documented in a database. In the same database, the interaction matrices are briefly documented, while the processes in the THMC diagrams are more thoroughly documented in a special so called Process Report, which forms an important supporting document for SR 97.

The Inventory of Depressive Symptomatology Self Report (IDS-SR: Psychometric properties of the Indonesian version.

Directory of Open Access Journals (Sweden)

Retha Arjadi

Full Text Available Depression screening and examination in Indonesia are highly challenging due to the disproportionately low number of mental health professionals in comparison to the Indonesian population. Self-report questionnaires on depression are cost-effective and time-efficient. The current study investigates the psychometric properties of the Indonesian Inventory of Depressive Symptomatology Self Report (IDS-SR.The participants were 904 Indonesians (aged 16-61; 50.2% female, recruited via an online survey using Qualtrics. Confirmatory factor analysis of the one-factor, three-factor, and four-factor model were explored. Convergent and divergent validity of the total score of the Indonesian IDS-SR and each factor were examined, as well as the Cronbach's Alpha reliability. In addition, an optimal cut-off score for the Indonesian IDS-SR was established using ROC curve analysis.The three-factor model of "cognitive/mood", "anxiety/arousal", and "sleep disturbance" was the best fit with the Indonesian IDS-SR data. Convergent and divergent validity were good. Cronbach's Alpha reliability was excellent for the total score, good for the factors "cognitive/mood" and "anxiety/arousal", but insufficient for the factor "sleep disturbance". The optimal cut-off score of the Indonesian IDS-SR was 14, with 87% sensitivity and 86% specificity.As a multifactorial instrument to measure depression that has good validity and reliability, the Indonesian IDS-SR can be used to assess depressive symptoms for the purpose of research and clinical practice. The optimal cut-off score of the Indonesian IDS-SR is in accordance with the internationally used cut-off score.

Temperature dependence of scintillation properties of SrMoO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Mikhailik, V.B., E-mail: vmikhai@hotmail.com [Diamond Light Source, Harwell Science Campus, Didcot OX11 0DE (United Kingdom); Elyashevskyi, Yu. [Department of Physics, University of Oxford, Keble Rd., Oxford OX1 3RH (United Kingdom); Scientific-technical and Educational Centre of Low Temperature Studies, I. Franko National University of Lviv, 50 Dragomanova Str., 79005 Lviv (Ukraine); Kraus, H. [Department of Physics, University of Oxford, Keble Rd., Oxford OX1 3RH (United Kingdom); Kim, H.J. [Department of Physics of Kyungpook National University, 1370 Sangyeok-dong, Buk-gu, Daegu 702-701 (Korea, Republic of); Kapustianyk, V.; Panasyuk, M. [Scientific-technical and Educational Centre of Low Temperature Studies, I. Franko National University of Lviv, 50 Dragomanova Str., 79005 Lviv (Ukraine)

2015-08-21

Studies of the X-ray luminescence and scintillation properties of a SrMoO{sub 4} crystal as function of temperature down to T=10 K have been carried out. The luminescence in SrMoO{sub 4} is quenched at room temperature, but below T<200 K the crystal exhibits a broad emission band with a maximum at a wavelength of 520 nm. The emission is attributed to the radiative decay of self-trapped excitons and defects acting as traps for the exactions at low temperatures. Such complex character of radiative decay is reflected in the kinetics which contains several components plus a contribution from delayed recombination at low temperatures. The temperature dependence of scintillation light output of SrMoO{sub 4} was studied. Comparing with a reference ZnWO{sub 4} crystal measured under the same experimental conditions it was found that the light output of SrMoO{sub 4} is 15±5%. It is suggested, therefore, that there is scope for optimisation of strontium molybdate for application as scintillator in cryogenic rare event searches.

Facile Synthesis of SrCO3-Sr(OH2/PPy Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

Directory of Open Access Journals (Sweden)

Alfredo Márquez-Herrera

2016-01-01

Full Text Available Pyrrole monomer was chemically polymerized onto SrCO3-Sr(OH2 powders to obtain SrCO3-Sr(OH2/polypyrrole nanocomposite to be used as a candidate for photocatalytic degradation of methylene blue dye (MB. The material was characterized by Fourier transform infrared (FTIR spectroscopy, UV/Vis spectroscopy, and X-ray diffraction (XRD. It was observed from transmission electronic microscopy (TEM analysis that the reported synthesis route allows the production of SrCO3-Sr(OH2 nanoparticles with particle size below 100 nm which were embedded within a semiconducting polypyrrole matrix (PPy. The SrCO3-Sr(OH2 and SrCO3-Sr(OH2/PPy nanocomposites were tested in the photodegradation of MB dye under visible light irradiation. Also, the effects of MB dye initial concentration and the catalyst load on photodegradation efficiency were studied and discussed. Under the same conditions, the efficiency of photodegradation of MB employing the SrCO3-Sr(OH2/PPy nanocomposite increases as compared with that obtained employing the SrCO3-Sr(OH2 nanocomposite.

Impedance spectroscopy of SrBi2Ta2O9 and SrBi2Nb2O9 ceramics correlation with fatigue behavior

International Nuclear Information System (INIS)

Chen, T.; Thio, C.; Desu, S.B.

1997-01-01

In this research, a fatigue model for ferroelectric materials is proposed. The reasons for the electrical fatigue resistance of SrBi 2 Ta 2 O 9 (SBT), SrBi 2 Nb 2 O 9 (SBN), and PbZr 1-x Ti x O 3 (PZT) are discussed in terms of the bulk ionic conductivities of the compounds. To obtain the bulk ionic conductivity of SBT and SBN, we have used impedance spectroscopy which provides an effective method that allows us to separate the individual contributions of bulk, grain boundaries, and electrode-ferroelectric interfaces from the total capacitor impedance. The bulk ionic conductivities of SBT and SBN (∼10 -7 S/cm) are much higher than those of the perovskite ferroelectrics, e.g., PZT (∼10 -11 -10 -10 S/cm). The high ionic conductivities led us to conclude that the good fatigue resistance of SrBi 2 Ta 2 O 9 and SrBi 2 Nb 2 O 9 is due to easy recovery of defects. Specifically, oxygen vacancies entrapped within the capacitors are easily released, resulting in limited space charge buildup and domain wall pinning during the polarization reversal process. However, the oxygen vacancies in PZT are trapped at trap sites to become space charges, resulting in capacitor fatigue. copyright 1997 Materials Research Society

Toxicity of inhaled 90SrCl2 in Beagle dogs. XIII

International Nuclear Information System (INIS)

Muggenburg, B.A.; Hahn, F.F.; Boecker, B.B.; Jones, R.K.; McClellan, R.O.; Pickrell, J.A.

1979-01-01

The metabolism, dosimetry and biological effects of inhaled 90 SrCl 2 in the Beagle dog are being studied to provide a basis for assessing the consequences of inhaling 90 Sr such as might be released in certain nuclear accidents. Seventy-two dogs were exposed to aerosols containing 90 Sr resulting in initial body burdens ranging from 2.5 to 250 μCi 90 Sr/kg body weight. To date, 60 90 Sr-exposed dogs have died or have been euthanized, six during the first 31 days after inhalation of 90 Sr with bone marrow aplasia and 54 between 585 and 5109 days after inhalation of 90 Sr. The latter group includes 32 dogs with bone-related neoplasms, two with upper respiratory tract carcinomas and five dogs with various diseases of the lower respiratory tract and heart. The other 15 dogs and diseases in organs that received little or no radiation dose, such as the gastrointestinal tract, urinary tract and the central nervous system. The skeletons of the dogs dying with bone-related neoplasms received initial radiation dose rates of 3.2 to 55 rads/day and cumulative doses to death of 2800 to 22 000 rads. Fourteen control dogs have died or been euthanized, two during the last year with mammary carcinoma and intestinal lymphosarcoma. Serial observations are continuing on the six surviving 90 Sr dogs and six controls

The spatial variation of initial 87Sr/86Sr ratios in the Toki granite, Central Japan. Implications for the intrusion and cooling processes of a granitic pluton

International Nuclear Information System (INIS)

Yuguchi, Takashi; Tsuruta, Tadahiko; Hama, Katsuhiro; Nishiyama, Tadao

2013-01-01

The spatial variation in initial 87 Sr/ 86 Sr ratios (SrI) in the Toki granite, Central Japan, shows heterogeneity ranging from 0.708942 to 0.710069, which provides information on the intrusion and cooling processes of plutons. The Toki granite has three mineralogy-based rock facies: muscovite-biotite granite (MBG), hornblende-biotite granite (HBG) and biotite granite (BG). Large SrI values were found to be distributed at the western margin (west MBG) and the lithologically central region (central BG), while small SrI values were found at the northeast margin (northeast MBG). Regions with high and low Sr concentrations were also found in the Toki granite. In the Sr-rich samples, SrI (0.708942-0.709789) increases with 100/Sr (0.7-1.5). This geochemical trend extends towards the country sedimentary rocks of the Mino Terrane, which can be interpreted to result from assimilation and fractional crystallization (AFC) between the original granitic magma and the Mino sedimentary rocks. The SrI values in the Sr-rich regions show a correlation with the Alumina Saturation Index (ASI). In particular, the west MBG, with large SrI values, is classified as a peraluminous granitoid with large ASI, suggesting that the western margin of the pluton was strongly affected by assimilation during the intrusion process. The Sr-poor samples are present both in the central BG, with large SrI values, and in the northeast MBG, with small SrI values. The Sr-poor samples have small ASI and large differentiation indices, indicating that the central BG and the northeast MBG were generated either by different AFC process with different amounts of contaminants or by the intrusion and fractionation of different source magma with different SrI values. Overall, the geochemical spatial variations found in the Toki granite can be explained by various degrees of assimilation and fractional crystallization in the magma chamber and/or multi-stage intrusions with different degrees of crystallization of

Solar Thermochemical Energy Storage Through Carbonation Cycles of SrCO3/SrO Supported on SrZrO3.

Science.gov (United States)

Rhodes, Nathan R; Barde, Amey; Randhir, Kelvin; Li, Like; Hahn, David W; Mei, Renwei; Klausner, James F; AuYeung, Nick

2015-11-01

Solar thermochemical energy storage has enormous potential for enabling cost-effective concentrated solar power (CSP). A thermochemical storage system based on a SrO/SrCO3 carbonation cycle offers the ability to store and release high temperature (≈1200 °C) heat. The energy density of SrCO3/SrO systems supported by zirconia-based sintering inhibitors was investigated for 15 cycles of exothermic carbonation at 1150 °C followed by decomposition at 1235 °C. A sample with 40 wt % of SrO supported by yttria-stabilized zirconia (YSZ) shows good energy storage stability at 1450 MJ m(-3) over fifteen cycles at the same cycling temperatures. After further testing over 45 cycles, a decrease in energy storage capacity to 1260 MJ m(-3) is observed during the final cycle. The decrease is due to slowing carbonation kinetics, and the original value of energy density may be obtained by lengthening the carbonation steps. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Les Néandertaliens étaient-ils essentiellement carnivores ? Résultats préliminaires sur les teneurs en Sr et en Ba de la paléobiocénose mammalienne de Saint-CésaireWere Neandertalians essentially carnivores? Sr and Ba preliminary results of the mammalian palaeobiocoenosis of Saint-Césaire

Science.gov (United States)

Balter, Vincent; Person, Alain; Labourdette, Nathalie; Drucker, Dorothée; Renard, Maurice; Vandermeersch, Bernard

2001-01-01

Strontium-calcium (Sr/Ca) and barium-calcium (Ba/Ca) ratios are reduced constantly between diet and bioapatite in mammal organisms. This phenomenon leads to a reduction in the Sr/Ca and Ba/Ca ratios at higher trophic level in predator-prey mammalian communities, and is applied here to the reconstruction of a castelperronian food web, which includes a Neanderthal specimen. Adapted chemical pretreatment allows to isolate bioapatite from diagenetic compounds for analysis of Ca, Sr and Ba. Sr/Ca and Ba/Ca results of the fauna are consistent with trophic predictions. Initial results for the Neandertal suggest that he was mostly carnivorous. Distribution of Ba/Ca values of bones of herbivorous taxa reveals that ruminant animals can be distinguished from non-ruminants. The biosegregation model predicts that the diet of the Neandertal was composed by about 97 % in weight of meat with a weak contribution of vegetable or fish, and that the association of fish and plant is excluded in any proportion.

Identification of reaction compounds in micrometric layers from gothic paintings using combined SR-XRD and SR-FTIR.

Science.gov (United States)

Salvadó, Nati; Butí, Salvador; Nicholson, James; Emerich, Hermann; Labrador, Ana; Pradell, Trinitat

2009-07-15

Synchrotron radiation X-ray diffraction (micro-SR-XRD) and Fourier transform infrared spectroscopy (micro-SR-FTIR) are used in the non-destructive identification of reaction and aging compounds from micrometric ancient painting layers. The combination of the micrometer size and non-destructive nature of the techniques together with the high resolution and brilliance of the synchrotron radiation has proved to be a procedure most advantageous for the study of reaction, aging and degradation processes. Copper, lead and calcium carboxylates and oxalates are determined in the chromatic, preparation and alteration layers from 15th century egg tempera and oil paintings. Their nature and crystallinity have been assessed. Some hypothesis about the mechanisms of development of both carboxylates and oxalates are presented.

Binding of Sr from milk by solid phase extraction with cryptand C222 sorbed on silica gel, cation exchange, chelating or adsorbent resins for simplified 90Sr analysis

International Nuclear Information System (INIS)

Tait, David; Wiechen, Arnold; Haase, Gerhard

1995-01-01

Several commercially available resins have been found to bind the bicyclic polyether cryptand C222 from aqueous acetonitrile solutions. The presence of C222 on some of these resins strongly improved their affinity for Sr, so that relatively small amounts of such resins sorbed Sr from milk. The resins investigated were silica gel, polyacrylic acid crosslinked with divinylbenzene (DVB), polystyrene crosslinked with divinylbenzene (PS-DVB) and PS-DVB containing sulphonate, aminomethylphosphonate, iminodiacetate and mercapto groups. The resins for which binding of C222 resulted in the largest improvement in Sr sorption from milk were PS-DVB containing mercapto groups (Chelite S) and silica gel (Si 60). Thus, 2 ml wet volume of either Chelite S containing 133 μmol of C222, or silica gel Si-60 containing 143 μmol of C222 sorbed 90 and 48%, respectively, of the Sr from 100-ml milk samples. As the sorption of Sr from milk by these systems is relatively slow, contact times of 24-36 h are required to attain these results. The Chelite S-C222 system separates Sr effectively from Cs and Ca. Under the conditions described here some 6% of the natural 40 K in milk sorbs with Sr to the resin. Ba behaves similarly to Sr. 90 Sr/ 90 Y sorbed on the silica gel Si-60-C222 system can be measured directly and efficiently by liquid scintillation counting. If adequate specificity can be attained this system might provide a very simple method of determining 90 Sr in milk

Quasi-two-dimensional Fermi-liquid state in Sr2RhO4-δ

International Nuclear Information System (INIS)

Nagai, Ichiro; Shirakawa, Naoki; Umeyama, Norio; Ikeda, Shin-ichi

2010-01-01

Single crystals of layered perovskite Sr 2 RhO 4-δ (δ=0.0 and 0.1) are successfully grown by the floating-zone method. Stoichiometric single crystals (Sr 2 RhO 4.0 ) are obtained by O 2 -annealing the as-grown crystals (Sr 2 RhO 3.9 ). Sr 2 RhO 4.0 and Sr 2 RhO 3.9 show quasi-two-dimensional Fermi-liquid behavior at low temperatures, whereas there are large differences in the anisotropy of electrical resistivity ρ c (3 K)/ρ ab (3 K) and Wilson ratio R w between Sr 2 RhO 4.0 and Sr 2 RhO 3.9 : ρ c (3 K)/ρ ab (3 K)=2400 (19000) and R w =3.8 (6.4) for Sr 2 RhO 4.0 (Sr 2 RhO 3.9 ). The differences observed between the temperature dependence of the in-plane electrical resistivity (T 2 RhO 4.0 and Sr 2 RhO 3.9 are mainly derived from those between the density of states and band structure near the corresponding Fermi level. This indicates that the changes in these physical properties, which are accompanied by oxygen defects in the Sr 2 RhO 4-δ system, can be explained by the rigid band model. Moreover, these results suggest that t 2g band-filling can be controlled by adjusting the oxygen defect content δ in the Sr 2 RhO 4-δ system. Although many similarities are observed in this study between the physical properties of Sr 2 RhO 4.0 and Sr 2 RuO 4 . Sr 2 RhO 4.0 does not exhibit superconductivity down to 36 mK. (author)

CHARACTERIZATION OF THE PARTIALLY PURIFIED PLANTARCIN SR18 PRODUCED BY LACTOBACILLUS PLANTARUM SR18

Directory of Open Access Journals (Sweden)

Wagih El-Shouny

2013-04-01

Full Text Available The bacteriocin bound to the cells and that secreted into the culture filtrate of Lactobacillus plantarum SR18 were precipitated by 75% ammomium sulphate, dialysed and further purified by Gel filtration on Sephadex G-100. Bacteriocins were purified from proteins bound to the cell of L. plantarum SR18 (plantarcin SR18 a and culture filtrate proteins (plantarcin SR18 b, respectively. The SDS-PAGE of partially purified Plantarcin SR18a showed a molecular weight of 3.5 KDa. While, plantarcin SR18 b had a molecular weight of 10.3 KDa. The antibacterial activity of the tested plantarcin SR18 preparations suffered no measurable loss after 45 min at 80ºC. Whereas, At 100ºC, significant decrease in the activity of bacteriocin preparations (60- 80 % took place by the end of 45 min. At pH ranged from 5-8, the activity of the plantarcin SR18 preparations suffered no measurable loss. Dissociating agents significantly affected the bacteriocin activity. Thus, tween 80 and mercaptoethanol increased the activity of bacteriocin preparations to 1.2-1.4 fold. Sodium dodecyl sulphate (SDS increased the activity of the tested bacteriocin preparations by about 20%.The lowest residual activity (60% was recorded after treatment with Triton X100 for 45 min. Protease completely inhibited the activities of all forms of plantarcin SR18 after 45 min at 37ºC.

Design of outer-rotor type multipolar SR motor for electric vehicle

International Nuclear Information System (INIS)

Nakamura, Kenji; Suzuki, Yosuke; Goto, Hiroki; Ichinokura, Osamu

2005-01-01

In this paper, we design an outer-rotor type multipolar switched reluctance (SR) motor, and examine an application of the SR motor to an electric vehicle (EV). The design is based on a nonlinear magnetic circuit model proposed by the authors. Using the model, we can calculate dynamic characteristics of a SR motor accurately. Furthermore, by combining the nonlinear magnetic circuit model with a motor drive circuit and motion equation of an EV, we can predict dynamic characteristics such as the maximum speed, acceleration torque, and a battery current of the EV

Magnetism in the p-type Monolayer II-VI semiconductors SrS and SrSe

Science.gov (United States)

Lin, Heng-Fu; Lau, Woon-Ming; Zhao, Jijun

2017-01-01

Using density functional theory calculations, we study the electronic and magnetic properties of the p-type monolayer II-VI semiconductors SrX (X = S,Se). The pristine SrS and SrSe monolayers are large band gap semiconductor with a very flat band in the top valence band. Upon injecting hole uniformly, ferromagnetism emerges in those system in a large range of hole density. By varying hole density, the systems also show complicated phases transition among nonmagnetic semiconductor, half metal, magnetic semiconductor, and nonmagnetic metal. Furthermore, after introducing p-type dopants in SrS and SrSe via substitutionary inserting P (or As) dopants at the S (or Se) sites, local magnetic moments are formed around the substitutional sites. The local magnetic moments are stable with the ferromagnetic order with appreciable Curie temperature. The ferromagnetism originates from the instability of the electronic states in SrS and SrSe with the large density of states at the valence band edge, which demonstrates a useful strategy for realizing the ferromagnetism in the two dimensional semiconductors. PMID:28378761

Electronic parameters of Sr2M2O7 (M = V, Nb, Ta) and Sr-O chemical bonding

DEFF Research Database (Denmark)

Atuchin, Victor V.; Grivel, Jean-Claude; Zhang, Zhaoming

2010-01-01

XPS measurements were carried out on Sr2Nb2O7 and Sr2Ta2O7 powder samples, which were synthesized using standard solid state method. The binding energy differences between the O 1s and cation core level, Δ(O-Sr) = BE(O 1s) - BE(Sr 3d5/2), was used to characterize the valence electron transfer...... on the formation of the Sr-O bonds. The chemical bonding effects were considered on the basis of our XPS results for Sr2Nb2O7 and Sr2Ta2O7 and the previously published structural and XPS data for other Sr-oxide compounds. A new empirical relationship between Δ(O-Sr) and L(Sr-O) was obtained. Possible applications...

Sr/Ca mass ratio determination in bones using fast neutron activation analysis

International Nuclear Information System (INIS)

Hult, Mikael; Fessler, Andreas

1998-01-01

The Sr/Ca mass ratio in human bones reveals information regarding the diet which is of interest in archaeology. By using fast neutron activation analysis this ratio can be measured in a non-destructive manner, which is important when bones are considered too precious to allow for destructive analysis. Simulations and measurements showed that the nuclear reactions 88 Sr(n, 2n) 87m Sr and 44 Ca(n, p) 44 K are highly useful for the purpose

90Sr and 89Sr in seawater off Japan as a consequence of the Fukushima Dai-ichi nuclear accident

Directory of Open Access Journals (Sweden)

N. Casacuberta

2013-06-01

Full Text Available The impact of the earthquake and tsunami on the east coast of Japan on 11 March 2011 caused a loss of power at the Fukushima Dai-ichi nuclear power plant (NPP that resulted in one of the most important releases of artificial radioactivity into the environment. Although several works were devoted to evaluating the atmospheric dispersion of radionuclides, the impact of the discharges to the ocean has been less investigated. Here we evaluate the distribution of Fukushima-derived 90Sr (n = 57 and 89Sr (n = 19 throughout waters 30–600 km offshore in June 2011. Concentrations of 90Sr and 89Sr in both surface waters and shallow profiles ranged from 0.8 ± 0.2 to 85 ± 3 Bq m−3 and from 19 ± 6 to 265 ± 74 Bq m−3, respectively. Because of its short half-life, all measured 89Sr was due to the accident, while the 90Sr concentrations can be compared to the background levels in the Pacific Ocean of about 1.2 Bq m−3. Fukushima-derived radiostrontium was mainly detected north of Kuroshio Current, as this was acting as a southern boundary for transport. The highest activities were associated with near-shore eddies, and larger inventories were found in the closest stations to Fukushima NPP. The data evidence a major influence of direct liquid discharges of radiostrontium compared to the atmospheric deposition. Existing 137Cs data reported from the same samples allowed us to establish a 90Sr / 137Cs ratio of 0.0256 ± 0.0006 in seawater off Fukushima, being significantly different than that of the global atmospheric fallout (i.e., 0.63 and may be used in future studies to track waters coming from the east coast of Japan. Liquid discharges of 90Sr to the ocean were estimated, resulting in an inventory of 53 ± 1 TBq of 90Sr in the inshore study area in June 2011 and total releases of 90Sr ranging from 90 to 900 TBq, depending upon the reported estimates of 137Cs releases that are considered.

Systematic variations of 87Sr/56Sr ratios, Sr compositions, selected major-oxide concentrations, and mineral abundances in piston cores from the Red Sea

International Nuclear Information System (INIS)

Boger, P.D.; Boger, J.L.; Faure, G.

1980-01-01

A mixing model is presented which relates the concentrations of Sr to the 87 Sr/ 86 Sr ratios and concentrations of other elements contained in a mixture of two components. The model is applied to the measured 87 Sr/ 86 Sr ratios, Sr, CaO, Fe 2 O 3 and SiO 2 concentrations of the detrital fractions of sediment from three piston cores representing different depositional environments in the Red Sea. The sediment is shown to be a mixture of two components derived from old sialic rocks and young volcanic rocks of the surrounding land masses. One of the cores contained a third component which is identified as authigenic Fe 2 O 3 . Removal of this contaminant is shown to return the system to its original detrital constituents. (Auth.)

Addition to the analysis of the Sr VI and Sr VII spectra

International Nuclear Information System (INIS)

Wyart, J.F.

1989-01-01

Fifty-six lines of multicharged strontium are measured with an improved wavelength accuracy, or interpreted for the first time. They are 4p-4s, 4p-5s and 4p-4d transitions in Sr VII and 4p-5s transitions in Sr VI. The revision of the singlet-triplet connection in Sr VII is supported by theoretical survey of the ground configuration in Ge-like ions. (orig.)

Cross-bridge blocker BTS permits direct measurement of SR Ca2+ pump ATP utilization in toadfish swimbladder muscle fibers.

Science.gov (United States)

Young, Iain S; Harwood, Claire L; Rome, Lawrence C

2003-10-01

Because the major processes involved in muscle contraction require rapid utilization of ATP, measurement of ATP utilization can provide important insights into the mechanisms of contraction. It is necessary, however, to differentiate between the contribution made by cross-bridges and that of the sarcoplasmic reticulum (SR) Ca2+ pumps. Specific and potent SR Ca2+ pump blockers have been used in skinned fibers to permit direct measurement of cross-bridge ATP utilization. Up to now, there was no analogous cross-bridge blocker. Recently, N-benzyl-p-toluene sulfonamide (BTS) was found to suppress force generation at micromolar concentrations. We tested whether BTS could be used to block cross-bridge ATP utilization, thereby permitting direct measurement of SR Ca2+ pump ATP utilization in saponin-skinned fibers. At 25 microM, BTS virtually eliminates force and cross-bridge ATP utilization (both BTS. At 25 microM, BTS had no effect on SR pump ATP utilization. Hence, we used BTS to make some of the first direct measurements of ATP utilization of intact SR over a physiological range of [Ca2+]at 15 degrees C. Curve fits to SR Ca2+ pump ATP utilization vs. pCa indicate that they have much lower Hill coefficients (1.49) than that describing cross-bridge force generation vs. pCa (approximately 5). Furthermore, we found that BTS also effectively eliminates force generation in bundles of intact swimbladder muscle, suggesting that it will be an important tool for studying integrated SR function during normal motor behavior.

Development of 90Sr-90Y generators

International Nuclear Information System (INIS)

Barrio, Graciela

2007-01-01

Yttrium-90 is a radioisotope of great interest in the field of Nuclear Medicine. It is considered one of the most important and most used radionuclides for radioimmunotherapeutical applications, especially promising for the treatment of certain types of cancer. Another important application of 90 Y is radio synovectomy. This radionuclide has a half-life of 64 hours, emits long range beta particles (maximum energy of 2.3 MeV) and decays, without intermediate nuclides, to a stable daughter. 90 Y may be obtained carrier-free, generated by the decay of its parent 90 Sr (half-life=28 years). 90 Sr is a product from uranium fission, and due to its long half-life, can be indefinitely used, which is certainly advantageous. It is present in great amounts, and needs to be processed and purified in order to be used as raw material for the generators. Generators of 90 Sr- 90 Y may thus be used during various months, due to 90 Sr long half-life. Several methods for the separation of 90 Y from 90 Sr by solvent extraction and ion exchange have been reported in literature. Thanks to its simplicity, ion exchange techniques have been more commonly used for this generator system. The main objective of this work was to develop a methodology for the preparation of 90 Sr- 90 Y generators, using cationic exchange resins. In such method, 90 Sr is strongly adsorbed in the resin and 90 Y is eluted by a 0.003 M EDTA solution. According to the quality control carried out, results showed that elution yields are greater than 65%, thus confirming the efficiency of the separation method used.

The effects of secondary mineral precipitates on {sup 90}Sr mobility at the Hanford Site, USA

Energy Technology Data Exchange (ETDEWEB)

Um, Wooyong [Pacific Northwest National Laboratory, 902 Battelle Blvd., MSIN P7-54, Richland, WA 99354 (United States); Division of Advanced Nuclear Engineering, Pohang University of Science and Technology - POSTECH (Korea, Republic of); Wang, Guohui; Serne, R. Jeffrey [Pacific Northwest National Laboratory, 902 Battelle Blvd., MSIN P7-54, Richland, WA 99354 (United States)

2013-07-01

The effects of secondary precipitates on {sup 90}Sr transport at the Hanford Site were investigated using quartz column experiments with simulated caustic tank waste leachates (STWL). Significantly enhanced retardation of Sr transport was observed in the column contacted with STWL due to Sr sorption and co-precipitation with neo-formed nitrate cancrinite. However, the column results also suggest that neo-formed secondary precipitates could behave like native mobile colloids that can enhance Sr transport. Initially immobilized Sr within secondary precipitates could re-mobilize given a change in the pore water background conditions. The mobility of the neo-formed Sr-bearing precipitates increased with increased solution flow rate. In the field, pore water contents and flow rates can be changed by snow-melt (or storm water) events or artificial infiltration. The increased pore water flow rate caused by these events could affect the mobility of {sup 90}Sr-containing secondary precipitates, which can be a potential source for facilitated Sr transport in Hanford Site subsurface environments. (authors)

Separation of 90Sr from Purex high level waste and development of a 90Sr-90Y generator

International Nuclear Information System (INIS)

Ramanujam, A.; Dhami, P.S.; Chitnis, R.R.; Achuthan, P.V.; Kannan, R.; Gopalakrishnan, V.; Balu, K.

2000-04-01

90 Y (T 1/2 =64.2 h) finds several applications in nuclear medicine. It is formed from the decay of 90 Sr which has a long half-life of 28.8 years. 90 Sr can be used as a long-lasting source for the production of carrier-free 90 Y. 90 Sr itself is abundantly available in high level waste (HLW) of PUREX origin. The present studies deal with the separation of pure 90 Sr from HLW and the subsequent separation of 90 Y from 90 Sr. Actinides and some of the fission products like lanthanides, zirconium, molybdenum and cesium were first removed from the HLW using methods based on solvent extraction and ion-exchange studied earlier in our laboratory. The resulting waste solution was used as a feed for the present process. The separation of 90 Sr from HLW was based on radiochemical method which involved a repeated scavenging with ferric hydroxide followed by strontium carbonate precipitation. The separation of 90 Y from 90 Sr was achieved by membrane separation technique. A compact generator is developed for this separation using a commercially available polytetrafluoroethylene (PTFE) membrane, impregnated with indigenously synthesised 2-ethylhexyl 2-ethylhexyl phosphonic acid (KSM-17). Generator system overcomes the drawbacks associated with conventional solvent extraction and ion-exchange based generators. The product is in chloride form and is suitable for complexation studies. After gaining an operating experience of ∼3 years in generating carrier-free 90 Y at 2 mCi level for initial studies in radiotherapeutic applications, the process was scaled up for the production of about 12 mCi of 90 Y to be used for animal studies before its application to patients. Radiochemical and chemical purity of the product was critically assayed by radiometry, ICP-AES, etc. The process is amenable for further scaling up. (author)

Investigations of 90 SR activity concentrations in animal bones in Croatia

Energy Technology Data Exchange (ETDEWEB)

Maracic, M.; Franic, Z.; Marovic, G. [Institute for Medical Research and Occupational Health, Zagreb (Croatia)

2006-07-01

The paper describes investigations of 90 Sr activity concentrations in long bones of some domestic animals (cows, pigs and lambs) collected over the last ten years in the Republic of Croatia. These investigations are a part of an extended and still ongoing monitoring programme of radioactive contamination of human environment in Croatia. Bone is a critical organ for the accumulation of many radionuclides, including 90 Sr, a highly toxic radionuclide, similar to calcium in its chemicalaviour and metabolic processes. It has been found that the 90 Sr activity concentrations in bones differ between respective animal species, the highest activity concentrations being found in lamb bones. As the decrease of activity concentrations can be generally described by the exponential function, by fitting the measured data to the theoretical curve was estimated the ecological half-life of 90 Sr in bones of respective species. In addition was investigated the relation between 90 Sr activity concentrations in bones and fallout. The transient increases and decreases in 90 Sr activity concentrations in bones can be partially explained by a variety of environmental physical factors that naturally fluctuate. (authors)

Investigations of 90 SR activity concentrations in animal bones in Croatia

International Nuclear Information System (INIS)

Maracic, M.; Franic, Z.; Marovic, G.

2006-01-01

The paper describes investigations of 90 Sr activity concentrations in long bones of some domestic animals (cows, pigs and lambs) collected over the last ten years in the Republic of Croatia. These investigations are a part of an extended and still ongoing monitoring programme of radioactive contamination of human environment in Croatia. Bone is a critical organ for the accumulation of many radionuclides, including 90 Sr, a highly toxic radionuclide, similar to calcium in its chemical behaviour and metabolic processes. It has been found that the 90 Sr activity concentrations in bones differ between respective animal species, the highest activity concentrations being found in lamb bones. As the decrease of activity concentrations can be generally described by the exponential function, by fitting the measured data to the theoretical curve was estimated the ecological half-life of 90 Sr in bones of respective species. In addition was investigated the relation between 90 Sr activity concentrations in bones and fallout. The transient increases and decreases in 90 Sr activity concentrations in bones can be partially explained by a variety of environmental physical factors that naturally fluctuate. (authors)

SR-Site groundwater flow modelling methodology, setup and results

International Nuclear Information System (INIS)

Selroos, Jan-Olof; Follin, Sven

2010-12-01

As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken three groundwater flow modelling studies. These are performed within the SR-Site project and represent time periods with different climate conditions. The simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. Three time periods are addressed; the Excavation and operational phases, the Initial period of temperate climate after closure, and the Remaining part of the reference glacial cycle. The present report is a synthesis of the background reports describing the modelling methodology, setup, and results. It is the primary reference for the conclusions drawn in a SR-Site specific context concerning groundwater flow during the three climate periods. These conclusions are not necessarily provided explicitly in the background reports, but are based on the results provided in these reports. The main results and comparisons presented in the present report are summarised in the SR-Site Main report

SR-Site groundwater flow modelling methodology, setup and results

Energy Technology Data Exchange (ETDEWEB)

Selroos, Jan-Olof (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Follin, Sven (SF GeoLogic AB, Taeby (Sweden))

2010-12-15

As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken three groundwater flow modelling studies. These are performed within the SR-Site project and represent time periods with different climate conditions. The simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. Three time periods are addressed; the Excavation and operational phases, the Initial period of temperate climate after closure, and the Remaining part of the reference glacial cycle. The present report is a synthesis of the background reports describing the modelling methodology, setup, and results. It is the primary reference for the conclusions drawn in a SR-Site specific context concerning groundwater flow during the three climate periods. These conclusions are not necessarily provided explicitly in the background reports, but are based on the results provided in these reports. The main results and comparisons presented in the present report are summarised in the SR-Site Main report.

Rapid Simultaneous Determination of 89Sr and 90Sr in Milk: A Procedure Using Cerenkov and Scintillation Counting

International Nuclear Information System (INIS)

2013-01-01

Since 2004, the IAEA programme related to the terrestrial environment has included activities aimed at developing and testing a set of procedures for the determination of radionuclides in environmental samples. Both 89Sr and 90Sr are fission products that can be, and have been, released to the environment during nuclear explosions and nuclear reactor accidents. Since strontium uptake from milk is an important pathway for incorporation of radioactive strontium into the human body, the rapid and accurate analysis of radioactive strontium isotopes in milk is of crucial importance in emergency situations in order to protect the public from radiation hazards. This report describes a new approach for the rapid determination of 89 Sr and 90Sr in milk using Cerenkov and scintillation counting methods that was tested and validated by the analysis of four spiked milk samples in terms of repeatability, reproducibility and trueness (relative bias) in accordance with ISO guidelines. The report also describes the calculation of the uncertainty budget. This research was proposed in 2007 at the Asia-Pacific regional meeting of the IAEA Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA) network. Several ALMERA network laboratories participated in the validation procedure by performing reproducibility tests. The resulting recommended procedure is designed to be of general use to a wide range of laboratories, including those in the ALMERA network. It is expected that this rapid method for determining 89 Sr and 90 Sr in milk will be useful in emergency conditions and for routine environmental monitoring of elevated levels of radioactivity

Expert Opinion in SR 97 and the SKI/SSI Joint Review of SR 97

Energy Technology Data Exchange (ETDEWEB)

Hora, Stephen

2002-09-01

The role of sensitivity and uncertainty analyses for radioactive waste disposal assessments is reviewed. The report covers a description of the these concepts were applied in the authorities' review of the safety report SR 97. With regard to the use of expert knowledge, the most significant weakness of SR 97 is absence of any standards, procedures, and even definitions for expert judgment. This situation needs to be dealt with by SKB in the near future as it denigrates the portions of the study that are well done. In developing expert judgment processes, SSI should ensure that SKB creates procedures that guarantee traceability and transparency. This will become very important as the repository system matures and receives greater public scrutiny. Both in the area of scenario creation and expert judgement, there are processes that have gained international acceptance. It would be in the best interest of SKB, and the public, to adhere these accepted approaches.

Expert Opinion in SR 97 and the SKI/SSI Joint Review of SR 97

International Nuclear Information System (INIS)

Hora, Stephen

2002-09-01

The role of sensitivity and uncertainty analyses for radioactive waste disposal assessments is reviewed. The report covers a description of the these concepts were applied in the authorities' review of the safety report SR 97. With regard to the use of expert knowledge, the most significant weakness of SR 97 is absence of any standards, procedures, and even definitions for expert judgment. This situation needs to be dealt with by SKB in the near future as it denigrates the portions of the study that are well done. In developing expert judgment processes, SSI should ensure that SKB creates procedures that guarantee traceability and transparency. This will become very important as the repository system matures and receives greater public scrutiny. Both in the area of scenario creation and expert judgement, there are processes that have gained international acceptance. It would be in the best interest of SKB, and the public, to adhere these accepted approaches

Experimental investigation and thermodynamic calculation of the Mg-Sr-Zr system

International Nuclear Information System (INIS)

Zhou, Hua; Chen, Chong; Du, Yong; Central South Univ., Hunan; Gong, Haoran

2016-01-01

Both experimental investigation and thermodynamic calculation were performed for the Mg-Sr-Zr system. Four decisive alloys were firstly selected and prepared using a powder metallurgy method to measure the isothermal section at 400 C via a combination of X-ray diffraction and electron probe microanalysis. No ternary compound has been observed for this ternary system. Four three-phase regions, (Mg) + (αZr) + Mg 17 Sr 2 , Mg 17 Sr 2 + (αZr) + Mg 38 Sr 9 , Mg 38 Sr 9 + (αZr) + Mg 23 Sr 6 , and Mg 23 Sr 6 + (αZr) + Mg 2 Sr, have been identified at 400 C. No appreciable ternary solubility has been detected in the binary Mg-Sr compounds. Phase transition temperatures of the Mg-Sr-Zr alloys were measured by means of differential scanning calorimetry. The thermodynamic calculations match well with the experimental data in the present work, indicating that no ternary thermodynamic parameters are needed for the thermodynamic description of this ternary system. In order to verify the reliability of the current thermodynamic calculations of the Mg-Sr-Zr system, eight as-cast alloys in the Mg-rich corner were also prepared. The calculated liquidus projection is consistent with the observed primary phase regions. The present thermodynamic calculations are reliable and can be used in the development of Mg alloys.

Methodological development for 87Sr/86Sr measurement in olive oil and preliminary discussion of its use for geographical traceability of PDO Nîmes (France).

Science.gov (United States)

Medini, Salim; Janin, Myriam; Verdoux, Patrick; Techer, Isabelle

2015-03-15

The lack of a geographical identification protocol for olive oils can lead to fraud and health risks. As some works call for Sr isotopes for the geographical identification of agri-food products, this study focus on the feasibility of extracting Sr from olive oils for isotopic measurements by TIMS. In fact, existing protocols for purification of Sr are unsuitable for lipid matrix. The defined protocol is applied to samples of PDO Nîmes olive oil. The accuracy of the extraction procedure is tested against isotopic standards. The values obtained are in conformity with NIST certified values. This consistency demonstrates that no modification of (87)Sr/(86)Sr ratio is brought about by this protocol. Consequently, the method is preliminary used on PDO Nîmes and Moroccan oils to evaluate the feasibility of a discriminant Sr signature on the two geographical products. This study provides promising results for the geographical discrimination and identification of PDO olive oils. Copyright © 2014 Elsevier Ltd. All rights reserved.

The use of O, H and Sr isotopes and carbamazepine to identify the origin of water bodies supplying a shallow alluvial aquifer

Science.gov (United States)

Sassine, Lara; Le Gal La Salle, Corinne; Lancelot, Joël; Verdoux, Patrick

2014-05-01

Alluvial aquifers are of great socio-economic importance in France since they supply 82% of drinking water production, though they reveal to be very vulnerable to pesticides and emerging organic contaminants. The aim of this work is to identify the origin of water bodies which contribute to the recharge of an alluvial aquifer for a better understanding of its hydrochemistry and transfer of contaminants therein. The study is based on an isotopic and geochemical tracers approach, including major elements, trace elements (Br, Sr),and isotopes (δ18O, δ2H, 87Sr/86Sr), as well as organic molecules. Indeed, organic molecules such as pharmaceutical compounds, more precisely carbamazepine and caffeine, have shown their use as indicators of surface water in groundwater. The study area is a partially-confined shallow alluvial aquifer, the so-called Vistrenque aquifer, located at 15 km from the Mediterranean Sea, in the Quaternary alluviums deposited by an ancient arm of the Rhône River, in Southern France. This aquifer constitutes a shallow alluvial layer in a NE-SW graben structure. It is situated between a karst aquifer in lower Cretaceous limestones, on the NW border, and the Costières Plateau, on the SE border, having a similar geology as the Vistrenque. The alluvial plain is crossed by a surface water network with the Vistre as the main stream, and a canal used for irrigation essentially, the BRL canal, which is fed by the Rhône River. δ18O and δ2H allowed to differentiate the BRL canal water, depleted in heavy isotopes (δ2H = -71.5o vs V-SMOW), and the more enriched local rainwater (δ2H = -35.5o vs V-SMOW). In the Vistre surface water a binary mixing were evidenced with the BRL canal water and the rainwater, as end members. Then, in the Vistrenque groundwater both the BRL and the Vistre contributions could be identified, as they still show contrasting signature with local recharge. This allows to highlight the surface water contribution to a heavily exploited

Revealing the atomic structure and strontium distribution in nanometer-thick La0.8Sr0.2CoO3−δ grown on (001)-oriented SrTiO3

KAUST Repository

Feng, Zhenxing; Yacoby, Yizhak; Hong, Wesley T.; Zhou, Hua; Biegalski, Michael D.; Christen, Hans M.; Shao-Horn, Yang

2014-01-01

Surface segregation in metal oxides can greatly influence the oxygen transport and surface oxygen exchange kinetics critical to the performance of solid-state devices such as oxygen permeation membranes and solid oxide fuel/electrolytic cell electrodes. Unfortunately detecting elemental distributions at the atomic scale near the surface remains challenging, which hampers the understanding of underpinning mechanisms and control of surface segregation for the design of high-performance materials. Using the coherent Bragg rod analysis (COBRA) method, we report the first direct 3D atomic imaging of a 4 nm-thick "La0.8Sr0.2CoO 3-δ"/SrTiO3 epitaxial film. Of significance, energy differential COBRA revealed pronounced Sr segregation (La 1-xSrxCoO3-δ, x ∼ 0.4) in the four unit cells from the top surface while complete Sr depletion was detected in the five unit cells from the "La0.8Sr0.2CoO 3-δ"/SrTiO3 interface. The drastic strontium compositional changes in the film were associated with large changes in the atomic positions of apical oxygen sites in the perovskite structure. Such Sr segregation tendencies toward the surface were also found in nominal "La0.6Sr0.4CoO3-δ" thin films, which can greatly enhance the surface oxygen exchange properties of oxides. The results presented here show that COBRA and the differential COBRA methods can be used to investigate a variety of electrochemically active systems providing atomic scale structural and chemical information that can help understand the physical and chemical properties of these systems and serve as a basis for comparison with DFT calculations. © 2014 The Royal Society of Chemistry.

Function modification of SR-PSOX by point mutations of basic amino acids

Directory of Open Access Journals (Sweden)

Chen Chunxia

2011-04-01

Full Text Available Abstract Background Atherosclerosis (AS is a common cardiovascular disease. Transformation of macrophages to form foam cells by internalizing modified low density-lipoprotein (LDL via scavenger receptor (SR is a key pathogenic process in the onset of AS. It has been demonstrated that SR-PSOX functions as either a scavenger receptor for uptake of atherogenic lipoproteins and bacteria or a membrane-anchored chemokine for adhesion of macrophages and T-cells to the endothelium. Therefore, SR-PSOX plays an important role in the development of AS. In this study the key basic amino acids in the chemokine domain of SR-PSOX have been identified for its functions. Results A cell model to study the functions of SR-PSOX was successfully established. Based on the cell model, a series of mutants of human SR-PSOX were constructed by replacing the single basic amino acid residue in the non-conservative region of the chemokine domain (arginine 62, arginine 78, histidine 80, arginine 82, histidine 85, lysine 105, lysine 119, histidine 123 with alanine (designated as R62A, R78A, H80A, R82A, H85A, K105A, K119A and H123A, respectively. Functional studies showed that the mutants with H80A, H85A, and K105A significantly increased the activities of oxLDL uptake and bacterial phagocytosis compared with the wild-type SR-PSOX. In addition, we have also found that mutagenesis of either of those amino acids strongly reduced the adhesive activity of SR-PSOX by using a highly non-overlapping set of basic amino acid residues. Conclusion Our study demonstrates that basic amino acid residues in the non-conservative region of the chemokine domain of SR-PSOX are critical for its functions. Mutation of H80, H85, and K105 is responsible for increasing SR-PSOX binding with oxLDL and bacteria. All the basic amino acids in this region are important in the cells adhesion via SR-PSOX. These findings suggest that mutagenesis of the basic amino acids in the chemokine domain of SR-PSOX may

Vadose Zone Infiltration Rates from Sr isotope Measurements

Science.gov (United States)

Maher, K.; Maher, K.; DePaolo, D. J.; DePaolo, D. J.; Conrad, M.

2001-12-01

Predicting infiltration rates and recharge through the vadose zone in arid regions is difficult and hence developing methods for the measurement of infiltration rates is important. We have been investigating the use of Sr isotope measurements for determining infiltration at the 200 Area plateau on the Hanford reservation in central Washington. In this context, infiltration affects the transport of contaminants to the water table as well as recharge of the groundwater system. Using Sr isotopes for this purpose requires drill core and water samples from the vadose zone, although leaches of the cores can substitute for water samples. Complementary information, including some constraints on regional recharge, can also be obtained using water samples from groundwater monitoring wells. The VZ method is based on the fact that the Sr isotope ratio of soil water just below the surface is often set by dissolution of aeolian material including carbonate, and this ratio is different from the average value in the deeper underlying vadose zone rock matrix. As water infiltrates, the Sr isotopic composition of the water changes toward the rock values as a result of Sr released from the rocks by weathering reactions. The rate of change with depth of the Sr isotope ratio of the vadose zone water is a function ultimately of q/R; the ratio of the infiltration flux (q) to the bulk rock weathering rate (R). Where it is possible to evaluate R, q can be estimated. As data accumulate it may be possible to improve the calibration of the method. At Hanford the vadose zone rock material is mostly unconsolidated sand, silt, and gravel of broadly granitic composition, which constitute the Hanford and Ringold formations. Annual precipitation is about 160 mm/yr. Drilling and coring of a ca. 70m hole to the water table in 1999 as part of the Hanford groundwater monitoring program, in a relatively undisturbed area of the site, allowed us to generate a unique Sr isotope data set. The Sr isotope

Input of 87Sr/86Sr ratios and Sr geochemical signatures to update knowledge on thermal and mineral waters flow paths in fractured rocks (N-Portugal)

International Nuclear Information System (INIS)

Marques, J.M.; Carreira, P.M.; Goff, F.; Eggenkamp, H.G.M.; Antunes da Silva, M.

2012-01-01

Strontium isotopes and other geochemical signatures are used to determine the relationships between CO 2 -rich thermal (Chaves: 76 °C) and mineral (Vilarelho da Raia, Vidago and Pedras Salgadas: 17 °C) waters discharging along one of the major NNE–SSW trending faults in the northern part of mainland Portugal. The regional geology consists of Hercynian granites (syn-tectonic-310 Ma and post-tectonic-290 Ma) intruding Silurian metasediments (quartzites, phyllites and carbonaceous slates). Thermal and mineral waters have 87 Sr/ 86 Sr isotopic ratios between 0.716713 and 0.728035. 87 Sr/ 86 Sr vs. 1/Sr define three end-members (Vilarelho da Raia/Chaves, Vidago and Pedras Salgadas thermal and mineral waters) trending from rainfall composition towards that of the CO 2 -rich thermal and mineral waters, indicating different underground flow paths. Local granitic rocks have 87 Sr/ 86 Sr ratios of 0.735697–0.789683. There is no indication that equilibrium was reached between the CO 2 -rich thermal and mineral waters and the granitic rocks. The mean 87 Sr/ 86 Sr ratio of the thermal and mineral waters (0.722419) is similar to the Sr isotopic ratios of the plagioclases of the granitic rocks (0.71261–0.72087). The spatial distribution of Sr isotope and geochemical signatures of waters and the host rocks suggests that the thermal and mineral waters circulate in similar but not the same hydrogeological system. Results from this study could be used to evaluate the applicability of this isotope approach in other hydrogeologic investigations.

A high 87Sr 86Sr mantle source for low alkali tholeiite, northern Great Basin

Science.gov (United States)

Mark, R.K.; Lee, Hu C.; Bowman, H.R.; Asaro, F.; McKee, E.H.; Coats, R.R.

1975-01-01

Olivine tholeiites, the youngest Tertiary units (about 8-11 m.y. old) at five widely spaced localities in northeastern Nevada, are geologically related to the basalts of the Snake River Plain, Idaho, to the north and are similar in major element and alkali chemistry to mid-ocean ridge basalts (MORB) and island arc tholeiites. The measured K (1250-3350 ppm), Rb (1??9-6??2 ppm) and Sr (140-240 ppm) concentrations overlap the range reported for MORB. Three of the five samples have low, unfractionated rare earth element (REE) patterns, the other two show moderate light-REE enrichment. Barium concentration is high and variable (100-780 ppm) and does not correlate with the other LIL elements. The rocks have 87Sr/86Sr = 0??7052-0??7076, considerably higher than MORB (~0??702-0??703). These samples are chemically distinct (i.e. less alkalic) from the olivine tholeiites from the adjacent Snake River Plain, but their Sr isotopic compositions are similar. They contain Sr that is distinctly more radiogenic than the basalts from the adjacent Great Basin. About 10 b.y. would be required for the mean measured Rb/Sr (~ 0??02) of these samples to generate, in a closed system, the radiogenic Sr they contain. The low alkali content of these basalts makes crustal contamination an unlikely mechanism. If the magma is uncontaminated, the time-averaged Rb/Sr of the source material must have been ~0??04. A significant decrease in Rb/Sr of the source material (a factor 2??) thus most probably occurred in the relatively recent (1??09 yr) past. Such a decrease of Rb/Sr in the mantle could accompany alkali depletion produced by an episode of partial melting and magma extraction. In contrast, low 87Sr 86Sr ratios indicate that the source material of the mid-ocean ridge basalts may have been depleted early in the Earth's history. ?? 1975.

How the nursing profession can contribute to sustainable development goals.

Science.gov (United States)

Benton, David; Shaffer, Franklin

2016-11-01

As of 1 January 2016, the UN sustainable development goals (SDGs) became the focus of global efforts on a wide range of development agenda. The SDGs have subsumed the work of the UN millennium development goals (MDGs), so it is timely to reflect on the contribution made by nurses and midwives, so that we can optimise the profession's contribution to the 17 SDGs. This article reports the results of a scientometrics analysis of the published literature related to the MDGs and SDGs indexed in CINAHL, which identified the underlying themes addressed by nurses and midwives. It shows how analysis demonstrates that although nursing was slow to engage with the MDG agenda, it has made some progress in contributing to SDG scholarship. So far this contribution has been narrowly focused, but the profession could contribute to all 17 of the SDG goals. Routine updates of the analysis described here could help monitor progress, identify gaps in nursing's contributions to the goals, and provide further impetus to its engagement in this major global policy initiative.

87Sr/88Sr a useful tool for the identification of geographic origin of Styrian pumpkin seed oils?

Science.gov (United States)

Meisel, T.; Bandoniene, D.; Zettl, D.; Maneiko, M.; Horschinegg, M.

2012-04-01

The authenticity and the geographic origin of Styrian pumpkin seed oil (PGI) a regional specialty needs to be protected, but the current specification of this high priced product does not include the proof of origin through analytical tools. As it turns out, this and many other products within the Protected Geographical Status (PGS) framework of the European Union, cannot be protected from fraud without forensic tools. In previous studies we were able to demonstrate, that distribution and content of trace elements in particular the rare earth elements, are useful parameters to discriminate Austrian from non-Austrian pumpkin seed oils and seeds. Unlike stable isotopes ratios (C and H), the trace element patterns are not influenced by changes in weather conditions and temperature during growing and harvesting cycle. Though the study of the distribution of element traces can be used not only for the identification of the geographic origin with very useful PLS and PCA models but also can identify fraud through mixing with other oils, this method need to be validated by other means. Radiogenic isotopes, in particular the 87Sr/86Sr isotope amount ratio has been successfully applied to food and other products for forensic studies. In this study we determined the 87Sr/86Sr isotope amount ratio in pumpkin seed oils extracted from seeds of known geographic origin from Austria, Russia and China, as these are the largest producers, to see if significant differences occur and if they can be used as a forensic tool. Although the total area of the Russian and the Chinese crop fields are magnitudes larger than the ones from Austria, it turns out that the variance of the Austrian 87Sr/86Sr data is much larger than that from other sources. Reasons are the large diversity of the Austrian geology (pre-varsican, alpine to sub-recent ages of the underlying bedrock of the soils can be found), the small farm sizes and the small scale production. In Russia large farms are situated on

Destabilization of the 6H-SrIrO3 polymorph through partial substitution of zinc and lithium

DEFF Research Database (Denmark)

Bremholm, Martin; K. Kim, Cindi; Hirai, Daigo

2012-01-01

We report on the destabilization of the 6H-SrIrO3 polymorph through partial substitutions of zinc and lithium for iridium to form perovskites. The perovskites crystallize in the orthorhombic space group Pbnm: SrIr1−xZnxO3 is found for 0.25 ≤ x ≤ 0.33, while SrIr1−xLixO3 is found only for x = 0...... show Curie–Weiss behavior, with relatively large temperature independent contributions, and that the iridium atoms have low effective moments, 0.52 to 1.08 μB per Ir. The resistivity of SrIr0.67Zn0.33O3, characterized by Mott variable range hopping type semiconducting behavior, indicates...

Use of /sup 85/Sr for the assessment of mineral metabolism in osteo-articular tuberculosis, osteomyelitis, and rheumatoid polyarthritis

Energy Technology Data Exchange (ETDEWEB)

Likhtarev, I A; Shakirov, E A; Ginzburg, V S; Saliev, T S

1976-04-01

The authors proposed the method for determining the period of half-elimination (T) of /sup 85/Sr from the part of the skeleton. The method is unified so, that it can be used in any clinic, which has a more or less equipped radioisotope diagnosis room. The authors conducted a statical analysis of the results of observation of 162 patients with osteo-articular tuberculosis, osteomyelitis and rheumatoid polyarthritis which enabled them to connect the half-elimination period of /sup 85/Sr from the part of the skeleton in the early metabolical phase with the prognosis of an anticipated outcome of the treatment. Moreover, with the increase of T more than 12h the possibility of an unfavorable outcome of treatment of the mentioned disease increases.

Toxicity of inhaled 90SrCl2 in beagle dogs. XI

International Nuclear Information System (INIS)

Muggenburg, B.A.; Rebar, A.H.; Benjamin, S.A.; Boecker, B.B.; Jones, R. K.; McClellan, R.O.; Pickrell, J.A.

1977-01-01

Studies on the metabolism, dosimetry, and effects of inhaled 90 SrCl 2 in the Beagle dog are continuing in an effort to provide a basis for assessing the consequences of inhaling 90 Sr such as might be released in certain nuclear accidents. Seventy-two dogs were exposed to aerosols containing 90 Sr resulting in initial body burdens ranging from 2.5 to 250 μCi 90 Sr/kg body weight. Forty-eight of these dogs are being maintained for lifetime observation. Twenty-five unexposed dogs serve as controls. The long-term retained burden (LTRB) in these dogs ranged from 1 to 120 μCi 90 Sr/kg. Twenty-four dogs with a mean LTRB of 38 μCi 90 Sr/kg have been assigned to a sacrifice study. Two of these dogs and one control dog were sacrificed at five days, one month and one year after inhalation of 90 Sr. To date, 51 90 Sr-exposed dogs have died or have been euthanized, six during the first 31 days after inhalation of 90 Sr with bone marrow aplasia and 45 between 585 and 4236 days after inhalation of 90 Sr. The latter group includes 12 dogs with bone-related hemangiosarcomas, 16 with osteosarcomas, three with fibrosarcomas, three with osteochondrosarcomas, one with osteochondrofibrosarcoma, two with leukemia, one with a baso-squamous carcinoma of the skull, one with a squamous cell carcinoma of the maxilla, one with a squamous cell carcinoma of the frontal sinus, one with a hemangiosarcoma of the heart, one with a myxosarcoma of the skull, one with transitional cell carcinoma, one with bronchioalveolar carcinoma, one with an epileptic seizure, one with pneumonia, one with cerebellar hemorrhage and three with a malabsorption syndrome

From beans to breams: how participatory workshops can contribute ...

African Journals Online (AJOL)

From beans to breams: how participatory workshops can contribute to marine conservation planning. ... conservation plan. We report on how this data void was filled using information provided by marine resource users, managers and scientists during participatory workshops. Participants described the distribution of reefs, ...

Tracing of aerosol sources in an urban environment using chemical, Sr isotope, and mineralogical characterization.

Science.gov (United States)

Duarte, Regina M B O; Matos, João T V; Paula, Andreia S; Lopes, Sónia P; Ribeiro, Sara; Santos, José Francisco; Patinha, Carla; da Silva, Eduardo Ferreira; Soares, Rosário; Duarte, Armando C

2017-04-01

In the framework of two national research projects (ORGANOSOL and CN-linkAIR), fine particulate matter (PM 2.5 ) was sampled for 17 months at an urban location in the Western European Coast. The PM 2.5 samples were analyzed for organic carbon (OC), water-soluble organic carbon (WSOC), elemental carbon (EC), major water-soluble inorganic ions, mineralogical, and for the first time in this region, strontium isotope ( 87 Sr/ 86 Sr) composition. Organic matter dominates the identifiable urban PM 2.5 mass, followed by secondary inorganic aerosols. The acquired data resulted also in a seasonal overview of the carbonaceous and inorganic aerosol composition, with an important contribution from primary biomass burning and secondary formation processes in colder and warmer periods, respectively. The fossil-related primary EC seems to be continually present throughout the sampling period. The 87 Sr/ 86 Sr ratios were measured on both the labile and residual PM 2.5 fractions as well as on the bulk PM 2.5 samples. Regardless of the air mass origin, the residual fractions are more radiogenic (representative of a natural crustal dust source) than the labile fractions, whose 87 Sr/ 86 Sr ratios are comparable to that of seawater. The 87 Sr/ 86 Sr ratios and the mineralogical composition data further suggest that sea salt and mineral dust are important primary natural sources of fine aerosols throughout the sampling period.

Crystal structure and energy band and optical properties of phosphate Sr3P4O13

International Nuclear Information System (INIS)

Zhang, Y.-C.; Cheng, W.-D.; Wu, D.-S.; Zhang, H.; Chen, D.-G.; Gong, Y.-J.; Kan, Z.-G.

2004-01-01

A single crystal of the compound Sr 3 P 4 O 13 has been found and the crystal structure has been characterized by means of single crystal X-ray diffraction analysis. The compound crystallizes in triclinic system and belongs to space group P1-bar. It builds up from SrO 7 polyhedra and P 4 O 13 -6 anions and has a layered structure, and the Sr atoms are located in the interlayer space. The absorption and luminescence spectrum of Sr 3 P 4 O 13 microcrystals have been measured. The calculated results of crystal energy band structure by the DFT show that the solid state of Sr 3 P 4 O 13 is an isolator with direct band gap. The calculated total and partial density of states indicate that the top valence bands are contributions from P 3p and O 2p states and low conduction bands mostly originate from Sr atomic states. The calculated optical response functions expect that the Sr 3 P 4 O 13 is a low refractive index, and it is possible that the Sr 3 P 4 O 13 is used to make transparent material between the UV and FR light zone

How Confident can we be in Flood Risk Assessments?

Science.gov (United States)

Merz, B.

2017-12-01

Flood risk management should be based on risk analyses quantifying the risk and its reduction for different risk reduction strategies. However, validating risk estimates by comparing model simulations with past observations is hardly possible, since the assessment typically encompasses extreme events and their impacts that have not been observed before. Hence, risk analyses are strongly based on assumptions and expert judgement. This situation opens the door for cognitive biases, such as `illusion of certainty', `overconfidence' or `recency bias'. Such biases operate specifically in complex situations with many factors involved, when uncertainty is high and events are probabilistic, or when close learning feedback loops are missing - aspects that all apply to risk analyses. This contribution discusses how confident we can be in flood risk assessments, and reflects about more rigorous approaches towards their validation.

Development of {sup 90}Sr-{sup 90}Y generators; Desenvolvimento de geradores de {sup 90}Sr-{sup 90}Y

Energy Technology Data Exchange (ETDEWEB)

Barrio, Graciela, E-mail: gracielabarrio@gmail.co [Pontificia Univ. Catolica de Sao Paulo (PUC-SP), SP (Brazil). Dept. de Fisica; Osso Junior, Joao Alberto, E-mail: jaossoj@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2007-07-01

Yttrium-90 is a radioisotope of great interest in the field of Nuclear Medicine. It is considered one of the most important and most used radionuclides for radioimmunotherapeutical applications, especially promising for the treatment of certain types of cancer. Another important application of {sup 90}Y is radio synovectomy. This radionuclide has a half-life of 64 hours, emits long range beta particles (maximum energy of 2.3 MeV) and decays, without intermediate nuclides, to a stable daughter. {sup 90}Y may be obtained carrier-free, generated by the decay of its parent {sup 90}Sr (half-life=28 years). {sup 90}Sr is a product from uranium fission, and due to its long half-life, can be indefinitely used, which is certainly advantageous. It is present in great amounts, and needs to be processed and purified in order to be used as raw material for the generators. Generators of {sup 90}Sr-{sup 90}Y may thus be used during various months, due to {sup 90}Sr long half-life. Several methods for the separation of {sup 90}Y from {sup 90}Sr by solvent extraction and ion exchange have been reported in literature. Thanks to its simplicity, ion exchange techniques have been more commonly used for this generator system. The main objective of this work was to develop a methodology for the preparation of {sup 90}Sr-{sup 90}Y generators, using cationic exchange resins. In such method, {sup 90}Sr is strongly adsorbed in the resin and {sup 90}Y is eluted by a 0.003 M EDTA solution. According to the quality control carried out, results showed that elution yields are greater than 65%, thus confirming the efficiency of the separation method used.

Methodical assessment of all non-ionizing radiation sources that can provide a relevant contribution to public exposure. Final report

International Nuclear Information System (INIS)

Bornkessel, Christian; Schubert, Markus; Wuschek, Matthias; Brueggemeyer, Hauke; Weiskopf, Daniela

2011-01-01

The aim of the research project was to systematically identify artificial sources on non-ionizing radiation (electric, magnetic or electromagnetic fields in a frequency range from 0 Hz to 300 GHz, as well optical radiation in a wavelength range from 100 nm to 1 mm), that have relevant contribution to public exposure. The report includes the following chapters: (1) Concept for the relevance assessment for non-ionizing radiation sources; (2) concept for the systematic identification of sources from establishes technologies; (3) concept for the systematic identification of sources from new or foreseeable technologies; (4)overview of relevant radiation sources.

Photoluminescence in Pb{sup 2+} activated SrB{sub 4}O{sub 7} and SrB{sub 2}O{sub 4} phosphors

Energy Technology Data Exchange (ETDEWEB)

Gawande, A.B., E-mail: gawandeab@gmail.com [Department of Physics, SGB Amravati University, Amravati-444602, Maharashtra (India); Ingle, J.T. [J. D. Institute of Engineering and Technology, Yavatmal, Maharashtra (India); Sonekar, R.P., E-mail: sonekar_rp@yahoo.com [Department of Physics, G.S. College, Khamgaon District, Buldhana, Maharashtra (India); Omanwar, S.K. [Department of Physics, SGB Amravati University, Amravati-444602, Maharashtra (India)

2014-05-01

The powder samples of SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} were prepared by solution combustion synthesis method. The synthesis is based on the exothermic reaction between the fuel (Urea) and Oxidizer (Ammonium nitrate). The synthesized materials were characterized using TG–DTA, powder XRD, SEM and the photoluminescence properties were studied using a Hitachi F-7000 spectrophotometer at room temperature. Both the samples SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} show broad emission of Pb{sup 2+} respectively at 307 nm and 360 nm (corresponds to {sup 3}P{sub 1} to {sup 1}S{sub 0} transition). The optimum concentrations of Pb{sup 2+} in both the phosphors SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} were found to be 3 mol% (relative to Sr) and for this concentration the critical transfer distance R{sub 0} were calculated to be 10.21 Å and 12.22 Å respectively. The Stokes shifts were calculated to be respectively 4464 cm{sup −1} and 8454 cm{sup −1}. The emission bands of both the phosphors are in the UV region and the phosphors can be potential candidates for application in UV lamps. - Highlights: • SrB{sub 4}O{sub 7}:Pb{sup 2+} and SrB{sub 2}O{sub 4}:Pb{sup 2+} have been synthesized by Novel solution combustion synthesis technique. • The synthesized materials were characterized using TG–DTA, powder XRD and SEM. • Photoluminescence spectra of synthesized materials showed the characteristic transition in Pb{sup 2+}. • Stokes shift, optimum concentration and critical transfer distance R{sub 0} were determined.

A model-independent comparison of the rates of uptake and short term retention of 47Ca and 85Sr by the skeleton.

Science.gov (United States)

Reeve, J; Hesp, R

1976-12-22

1. A method has been devised for comparing the impulse response functions of the skeleton for two or more boneseeking tracers, and for estimating the contribution made by measurement errors to the differences between any pair of impulse response functions. 2. Comparisons were made between the calculated impulse response functions for 47Ca and 85Sr obtained in simultaneous double tracer studies in sixteen subjects. Collectively the differences between the 47Ca and 85Sr functions could be accounted for entirely by measurement errors. 3. Because the calculation of an impulse response function requires fewer a priori assumptions than other forms of mathematical analysis, and automatically corrects for differences induced by recycling of tracer and non-identical rates of excretory plasma clearance of tracer, it is concluded that differences shown in previous in vivo studies between the fluxes of Ca and Sr into bone can be fully accounted for by undetermined oversimplifications in the various mathematical models used to analyse the results of those studies. 85Sr is therefore an adequate tracer for bone calcium in most in vivo studies.

Areal distribution of 60Co, 137Cs, and 90Sr in streambed gravels of White Oak Creek Watershed, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Cerling, T.E.; Spalding, B.P.

1981-01-01

The concentrations of 90 Sr, 60 Co, and 137 Cs in streambed gravels from contaminated drainages in White Oak Creek Watershed were determined. Methods to determine the relative contributions of various sources to the total discharge from the watershed were developed. Principal sources of 90 Sr were: ORNL plant effluents (50%), leaching from solid waste disposal area (SWDA) 4 (30%), and leaching from SWDA 5 (10%). Minor sources included SWDA 3, the Molten Salt Reactor Facility, and intermediate-level liquid waste pit 1 with each representing 4% or less of the total basin discharge. The cooling water effluent from the High-Flux Isotope Reactor was the dominant source of 60 Co contamination in the watershed. ORNL plant effluents accounted for almost all the 137 Cs discharge from White Oak Creek basin. Downstream radionuclide concentrations were constant until significant dilution by other tributaries occurred. Any future activities giving rise to additional contamination can now be identified. Distribution coefficients between streambed gravels and streamwater for 85 Sr, 60 Co, and 137 Cs were 50, 560, and 8460 ml/g, respectively. An abridged radiochemical fractionation developed for 90 Sr was found to be as accurate and precise for these samples as the standard 90 Sr method above levels of 2 dpm/g

Use of Sr and Pb isotopes in gneissic-migmatic rocks in Itacambira-Barrocao, MG, Brazil

International Nuclear Information System (INIS)

Siga Junior, O.; Cordani, U.G.; Basei, M.A.S.; Kawashita, K.

1987-01-01

This work tries to show the potential of the Rb-Sr, Pb-Pb and K-Ar methods applied to basic geological mapping. The different interpretative values of these methodologies contribute to the understanding of the tectonic processes developed in the southeastern border of the Sao Francisco Craton. The Rb-Sr and Pb-Pb isotopic data for the gneissic-migmatitic unit of this sector indicates their generation during the Archean (-2.7 Ga) and Early Proterozoic (-2.1 Ga.). The high (Sr 87 /Sr 86 ) and μ 1 values also suggest an origin through reworking of older crustal rocks. The K-Ar data (and one fission track age) allow the thermal history of this domain to be delineated and suggest a vertical tectonic in the Late Brazilian Cycle, putting side by side blocks formed in different depths. (M.V.M.)

A ferroelectric switchable tunnel junction: KNbO{sub 3}/SrTiO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Rahmanizadeh, Kourosh; Bihlmayer, Gustav; Wortmann, Daniel; Bluegel, Stefan [Peter Gruenberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1), Forschungszentrum Juelich and JARA, 52425 Juelich (Germany)

2012-07-01

The properties of thin oxide films and multilayers are strongly influenced by defects and, therefore, can be controllably tuned by the defect concentration at the interface. For example, due to the charge discontinuity at the SrTiO{sub 3}/KO-KNbO{sub 3}-NbO{sub 2}/SrTiO{sub 3} interface only one direction of polarization in KNbO{sub 3} film is stable. A switchable polarization in KNbO{sub 3} can be realized by creating (oxygen) defects at the interfaces. We carried out density functional theory (DFT) calculations based on the full potential linearized augmented planewave (FLAPW) method as implemented in the FLEUR code for studying the polar interface SrTiO{sub 3}/KNbO{sub 3} and a SrRuO{sub 3}/SrTiO{sub 3}/KNbO{sub 3} tunnel junction. The electronic transport properties of the switchable multiferroic SrRuO{sub 3}/SrTiO{sub 3}/KO-KNbO{sub 3}-NbO{sub 3}/SrTiO{sub 3}/SrRuO{sub 3} heterostructure have been investigated using an embedded Green-function approach. A strong dependence of the (magneto electric) transport properties on the polarization is observed.

Thermoelectric and spincaloric properties of epitaxial LaNiO{sub 3}/SrTiO{sub 3} superlattices from first principles

Energy Technology Data Exchange (ETDEWEB)

Geisler, Benjamin [FRM II, Technische Universitaet Muenchen, Garching (Germany); Fakultaet fuer Physik, Universitaet Duisburg-Essen, Duisburg (Germany); Blanca-Romero, Ariadna [Imperial College, London (United Kingdom); Pentcheva, Rossitza [Fakultaet fuer Physik, Universitaet Duisburg-Essen, Duisburg (Germany)

2016-07-01

Modern layer-by-layer fabrication techniques make it possible to grow epitaxial oxide superlattices with atomic precision. By combining accurate DFT+U calculations to determine the atomic and electronic structure and Boltzmann transport theory we show how a targeted design of the interface composition can be used to optimize the thermoelectric and/or spincaloric properties of LaNiO{sub 3}/SrTiO{sub 3}(001) superlattices. A TiO{sub 2}/LaO interface induces n-type doping, and a (potentially highly spin-polarized) charge current arises solely in-plane in the NiO{sub 2} layers. The out-of-plane resistance is high, since the SrTiO{sub 3} layers act as tunneling barriers. In contrast, a NiO{sub 2}/SrO interface leads to p-type doping. In this case, also the valence band of SrTiO{sub 3} contributes to the transmission, thereby reducing the out-of-plane resistance significantly. Besides this doping effect we find that the interface composition influences the electronic band structure, which leads to a nontrivial behavior of the Seebeck coefficient. Funding by the DFG within TRR 80 (G3 and G8) is acknowledged.

How can LCA approaches contribute to improve geo-cycles management

Science.gov (United States)

Carreiras, M.; Ferreira, A. J. D.; Esteves, T. C. J.; Delgado, F.; Andrade, F.; Franco, J.; Pereira, C. D.

2012-04-01

Climate change and land use have become a major challenge for mankind and the natural environment. Greenhouse gas (GHG) emissions released into the atmosphere in ever rapidly growing volumes are most likely to be responsible for this change. Carbon dioxide gas (CO2) is suggested to be the main cause of global warming. Carbon reduction is the key to preventing this, for example, by enhancing energy efficiency and mitigating carbon emissions by means of green energy and adjusting the use of natural resources. Different activities produce distinguish impacts, and each product generates specific impacts on nature. The impact of man activities in the geo-cycles is of paramount importance in what concerns long term sustainability. Nevertheless, the environmental and sustainability impacts of different approaches and techniques of ecosystem management is a difficult question that can be assessed using LCA techniques LCA is a technique to assess environmental impacts associated with all the stages of a product's life from-cradle-to-grave. Based on that, LCA can be effective in supporting the assessment of decision making on complex sustainability issues because it can integrate the diversity of impacts categories guise and it can be adapted to a large variety of contexts. By incorporating quantitative data LCA allows decision makers to include a full range of economic, environmental, social and technical criteria. The integrated framework is configured such that the pros and cons of alternative environmental and energy strategies can be measured in terms of their ability to achieve the overall goals and objectives of the sustainable development, while satisfying the pollution control requirements. Because it is holistic, integrate and dynamic, this approach represents a state of the art tool for enhance the sustainable development of a sector, allowing a more transparent and participated management, a basic instrument for improved competitiveness. This approach may serve

Strain-Mediated Inverse Photoresistivity in SrRuO3/La0.7Sr0.3MnO3Superlattices

KAUST Repository

Liu, Heng-Jui

2015-12-09

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. In the pursuit of novel functionalities by utilizing the lattice degree of freedom in complex oxide heterostructure, the control mechanism through direct strain manipulation across the interfaces is still under development, especially with various stimuli, such as electric field, magnetic field, light, etc. In this study, the superlattices consisting of colossal-magnetoresistive manganites La0.7Sr0.3MnO3 (LSMO) and photostrictive SrRuO3 (SRO) have been designed to investigate the light-dependent controllability of lattice order in the corresponding functionalities and rich interface physics. Two substrates, SrTiO3 (STO) and LaAlO3 (LAO), have been employed to provide the different strain environments to the superlattice system, in which the LSMO sublayers exhibit different orbital occupations. Subsequently, by introducing light, we can modulate the strain state and orbital preference of LSMO sublayers through light-induced expansion of SRO sublayers, leading to surprisingly opposite changes in photoresistivity. The observed photoresistivity decreases in the superlattice grown on STO substrate while increases in the superlattice grown on LAO substrate under light illumination. This work has presented a model system that demonstrates the manipulation of orbital-lattice coupling and the resultant functionalities in artificial oxide superlattices via light stimulus. A fascinating model system of optic-driven functionalities has been achieved by artificial superlattices consisting of manganite La0.7Sr0.3MnO3 (LSMO) and photostrictive SrRuO3 (SRO). With design of different initial strain and orbital states in superlattices, we can even control the photoresistivity of the superlattices in an opposite trend that cannot be achieved in pure single film.

Evolution of {sup 137}Cs and {sup 90}Sr content of the main foodstuff in Bucharest area after the Chernobyl accident

Energy Technology Data Exchange (ETDEWEB)

Toader, M; Vasilache, R A [Institute of Hygiene and Public Health, Bucharest (Romania)

1997-09-01

Soon after the Chernobyl accident, the radioactive cloud, carrying the nuclides released into the atmosphere, reached Romania and, due to the rainy weather, an important fallout occurred over the Romanian territory. The most important contaminants for Romania were I{sup 131}, Cs{sup 134}, Cs{sup 137} and Sr{sup 90}. As in many other countries, in the first days, I{sup 131} had the main contribution to the irradiation dose released to the population. After its decay, and the decay of other short-lived radionuclides, Cs{sup 137} and Sr{sup 90} remained the most important contaminants. The principal route of intake for these two radionuclides is considered to be the ingestion of contaminated foods. To assess the radioactive burden of foods, a long term, large scale survey was initiated at the National Institute of Hygiene and Public Health (INISP). These results were then used to assess the doses committed to cesium and strontium intake and the excedentary cancer risk for the population from Bucharest area. 5 refs, 8 figs.

The review of separation technology for fission nuclides 90Sr and 137Cs

International Nuclear Information System (INIS)

Zhang Huaming; Li Xingliang; Luo Shunzhong; Peng Shuming; Lei Jiarong

2010-01-01

The progress of separation technologies for fission nuclides 90 Sr and 137 Cs, including precipitation method, liquid-liquid extraction process and ion exchanging operation, are mainly reviewed. Crown ether (DtBuCH18C6) and calixarene-crown ether (BOBCalixC6) can be highly selective for 90 Sr and 137 Cs respectively in acidic waste; Ionic liquids extraction and supercritical fluid extraction can be applied for separation 90 Sr and 137 Cs from high level waste. Crystalline silicotitiate (CST) and metal sulfide (KMS-1) have highly selectivity for 90 Sr and 137 Cs separately in basic condition. The prospects of disposal technology for high level waste are also discussed in this review. (authors)

DOE Spent Nuclear Fuel Information in Support of TSPA-SR

Energy Technology Data Exchange (ETDEWEB)

H. H. Loo

1999-08-01

The Department of Energy (DOE) Office of Civilian Radioactive Waste Management (RW) has started the recommendation (SR) effort to show that Yucca Mountain could be selected as the first geologic repository for spent nuclear fuel (SNF) and high-level waste. One component of the site recommendation will be a total system performance assessment (TSPA), based on the design concept and the scientific data and analysis available, describing the repository's probable behavior relative to the overall system performance standards. Thus, all the data collected from the Exploratory Studies Facilities to-date have been incorporated into the latest TSPA model. To ensure that the DOE-owned SNF continues to be acceptable for disposal in the repository, it will be included in the TSPA-SR evaluation. A number of parameters are needed in the TSPA-SR models to predict the performance of the DOE-owned SNF materials placed into the potential repository. This report documents all of the basis and/or derivation for each of these parameters. A number of properties were not readily available at the time the TSPA-SR data were requested. Thus, expert judgement and opinion were used to determine a best property value. The performance of the DOE-owned SNF will be published as part of the TSPA-SR report.

Quantum Logic with Composite Pulse Sequences on Sr^+

Science.gov (United States)

Shewmon, Ruth; Labaziewicz, Jaroslaw; Ge, Yufei; Wang, Shannon; Chuang, Isaac L.

2008-03-01

The optical 5S1/2->4D1/2 transition in Sr^+ is an attractive qubit because it can be addressed by diode lasers, which are relatively inexpensive and easy to operate. We characterize single-qubit rotations as well as a CNOT gate on a Sr^+ ion in a surface electrode Paul trap. To improve these operations, the frequency of the clock laser is stabilized to a high-finesse optical cavity. The resulting linewidth of the laser is approximately 300Hz. Composite pulse sequences, a technique adapted from NMR, have been shown to reduce the effects of systematic errors in a variety of quantum systems. We demonstrate several composite sequences that improve the fidelity of quantum logic operations on Sr^+.

Rb-Sr isochronous age of Vepor pluton granitoids

International Nuclear Information System (INIS)

Bagdasaryan, G.P.; Gykasyan, R.Kh.; Cambel, B.

1986-01-01

The result are presented of geochronological investigations of the Vepor pluton granitoids by the Rb-Sr isochronous method. The results prove the Variscan age of granodiorite magmatism of the Sihla type (387±27 m.y.) and the Early Variscan age of leucocratic granitoids of the Vepor and the Ipel types (284±22 m.y.). Since the initial ratio of 87 Sr/ 86 Sr in granitoids of the Sihla type is 0.7054 and of the Vepor type 0.7060, it can be assumed that during the formation of the granitoids of veporides there was an increased supply of matter from the main source affecting genesis of granitoids. The results prove a polyphase character of the Variscan granitoids of Veporicum. (author)

SR proteins in vertical integration of gene expression from transcription to RNA processing to translation.

Science.gov (United States)

Zhong, Xiang-Yang; Wang, Pingping; Han, Joonhee; Rosenfeld, Michael G; Fu, Xiang-Dong

2009-07-10

SR proteins have been studied extensively as a family of RNA-binding proteins that participate in both constitutive and regulated pre-mRNA splicing in mammalian cells. However, SR proteins were first discovered as factors that interact with transcriptionally active chromatin. Recent studies have now uncovered properties that connect these once apparently disparate functions, showing that a subset of SR proteins seem to bind directly to the histone 3 tail, play an active role in transcriptional elongation, and colocalize with genes that are engaged in specific intra- and interchromosome interactions for coordinated regulation of gene expression in the nucleus. These transcription-related activities are also coupled with a further expansion of putative functions of specific SR protein family members in RNA metabolism downstream of mRNA splicing, from RNA export to stability control to translation. These findings, therefore, highlight the broader roles of SR proteins in vertical integration of gene expression and provide mechanistic insights into their contributions to genome stability and proper cell-cycle progression in higher eukaryotic cells.

Presentation of safety after closure of the repository for spent nuclear fuel. Main report of the project SR-Site. Part III

International Nuclear Information System (INIS)

2011-01-01

The purpose of the safety assessment SR-Site is to investigate whether a safe repository for spent nuclear fuel by KBS-3 type can be constructed at Forsmark in Oesthammar in Sweden. The location of the Forsmark has been selected based on results of several surveys from surface conditions at depth in Forsmark and in Laxemar in Oskarshamn. The choice of location is not justified in SR-Site Report, but in other attachments to SKB's permit applications. SR-Site Report is an important part of SKB's permit applications to construct and operate a repository for spent nuclear fuel at Forsmark in Oesthammar. The purpose of the report in the applications is to show that a repository at Forsmark is safe after closure

Presentation of safety after closure of the repository for spent nuclear fuel. Main report of the project SR-Site. Part I

International Nuclear Information System (INIS)

2011-01-01

The purpose of the safety assessment SR-Site is to investigate whether a safe repository for spent nuclear fuel by KBS-3 type can be constructed at Forsmark in Oesthammar in Sweden. The location of the Forsmark has been selected based on results of several surveys from surface conditions at depth in Forsmark and in Laxemar in Oskarshamn. The choice of location is not justified in SR-Site Report, but in other attachments to SKB's permit applications. SR-Site Report is an important part of SKB's permit applications to construct and operate a repository for spent nuclear fuel at Forsmark in Oesthammar. The purpose of the report in the applications is to show that a repository at Forsmark is safe after closure

Importance of d-wave contributions in the charge symmetry breaking reaction dd →4Heπ0

Science.gov (United States)

Adlarson, P.; Augustyniak, W.; Bardan, W.; Bashkanov, M.; Bergmann, F. S.; Berłowski, M.; Bondar, A.; Büscher, M.; Calén, H.; Ciepał, I.; Clement, H.; Czerwiński, E.; Demmich, K.; Engels, R.; Erven, A.; Erven, W.; Eyrich, W.; Fedorets, P.; Föhl, K.; Fransson, K.; Goldenbaum, F.; Goswami, A.; Grigoryev, K.; Gullström, C.-O.; Hanhart, C.; Heijkenskjöld, L.; Hejny, V.; Hüsken, N.; Jarczyk, L.; Johansson, T.; Kamys, B.; Kemmerling, G.; Khatri, G.; Khoukaz, A.; Khreptak, O.; Kirillov, D. A.; Kistryn, S.; Kleines, H.; Kłos, B.; Krzemień, W.; Kulessa, P.; Kupść, A.; Kuzmin, A.; Lalwani, K.; Lersch, D.; Lorentz, B.; Magiera, A.; Maier, R.; Marciniewski, P.; Mariański, B.; Morsch, H.-P.; Moskal, P.; Ohm, H.; Parol, W.; Perez del Rio, E.; Piskunov, N. M.; Prasuhn, D.; Pszczel, D.; Pysz, K.; Pyszniak, A.; Ritman, J.; Roy, A.; Rudy, Z.; Rundel, O.; Sawant, S.; Schadmand, S.; Schätti-Ozerianska, I.; Sefzick, T.; Serdyuk, V.; Shwartz, B.; Sitterberg, K.; Skorodko, T.; Skurzok, M.; Smyrski, J.; Sopov, V.; Stassen, R.; Stepaniak, J.; Stephan, E.; Sterzenbach, G.; Stockhorst, H.; Ströher, H.; Szczurek, A.; Trzciński, A.; Wolke, M.; Wrońska, A.; Wüstner, P.; Yamamoto, A.; Zabierowski, J.; Zieliński, M. J.; Złomańczuk, J.; Żuprański, P.; Żurek, M.; WASA-at-COSY Collaboration

2018-06-01

This letter reports a first quantitative analysis of the contribution of higher partial waves in the charge symmetry breaking reaction dd →4Heπ0 using the WASA-at-COSY detector setup at an excess energy of Q = 60MeV. The determined differential cross section can be parametrized as d σ /d Ω = a + bcos2 ⁡θ*, where θ* is the production angle of the pion in the center-of-mass coordinate system, and the results for the parameters are a = (1.55 ± 0.46(stat) + 0.32 - 0.8 (syst)) pb /sr and b = (13.1 ± 2.1 (stat)-2.7+1.0 (syst)) pb /sr. The data are compatible with vanishing p-waves and a sizable d-wave contribution. This finding should strongly constrain the contribution of the Δ isobar to the dd →4Heπ0 reaction and is, therefore, crucial for a quantitative understanding of quark mass effects in nuclear production reactions.

81Br, 37Cl, and 87Sr studies to assess groundwater flow and solute sources in the southwestern Great Artesian Basin, Australia

International Nuclear Information System (INIS)

Gwynne, Rhys; Frape, Shaun; Shouakar-Stash, Orfan; Love, Andy

2013-01-01

The Great Artesian Basin (GAB) is a water source for more than 200,000 residents in central Australia. This study investigates the relationship of bromine and chlorine stable isotopes to groundwater chemistry in a confined aquifer in the southwestern GAB to better understand its flow regime and solute sources. δ 81 Br values range from +0.660/00 near the recharge area to +1.04 0/00, 150 km down gradient, while δ 37 Cl ranges from 00/00 to -2.50/00. While δ 37 Cl decreases with distance from the recharge area, δ 81 Br increases slightly. Bromide in the recharge area is possibly enriched from selective atmospheric processes causing fractionation in marine aerosols during transport. When confined and isolated from the atmosphere, increases in bromide and to a lesser extent strontium concentrations may contribute through water-rock interaction to changes in isotopic signatures along the flow system. 87 Sr/ 86 Sr values range from ∼0.717 near the recharge zone to a depleted 0.708 160 km down gradient. (authors)

Identification of Marchfeld asparagus using Sr isotope ratio measurements by MC-ICP-MS.

Science.gov (United States)

Swoboda, S; Brunner, M; Boulyga, S F; Galler, P; Horacek, M; Prohaska, T

2008-01-01

This work focuses on testing and application of Sr isotope signatures for the fast and reliable authentication and traceability of Asparagus officinalis originating from Marchfeld, Austria, using multicollector inductively coupled plasma mass spectrometry after optimised Rb/Sr separation. The major sample pool comprises freeze-dried and microwave-digested asparagus samples from Hungary and Slovakia which are compared with Austrian asparagus originating from the Marchfeld region, which is a protected geographical indication. Additional samples from Peru, The Netherlands and Germany were limited in number and allowed therefore only restricted statistical evaluation. Asparagus samples from Marchfeld were harvested within two subsequent years in order to investigate the annual variation. The results show that the Sr isotope ratio is consistent within these 2 years of investigation. Moreover, the Sr isotope ratio of total Sr in soil was found to be significantly higher than in an NH4NO3 extract, reflecting the mobile (bioavailable) phase. The isotope composition in the latter extract corresponds well to the range found in the asparagus samples in Marchfeld, even though the concentration of Sr in asparagus shows no direct correlation to the concentration of Sr in the mobile phase of the soil. The major question was whether the 'Marchfelder Spargel' can be distinguished from samples from the neighbouring countries of Hungary and Slovakia. According to our findings, they can be clearly (100%) singled out from the Hungarian samples and can be distinguished from the Slovakian asparagus samples with a probability of more than 80%.

The combined use of 87Sr/86Sr and carbon and water isotopes to study the hydrochemical interaction between groundwater and lakewater in mantled karst

Science.gov (United States)

Katz, Brian G.; Bullen, Thomas D.

1996-12-01

distinct hydrogeologic units displays considerable variability in Sr concentration and isotopic composition, the dominant processes associated with the mixing of lakewater leakage with groundwater, as well as the effects of mineral-water interaction, can be ascertained by integrating the use of stable and radiogenic isotopic measurements of groundwater, lakewater, and aquifer minerals.

Transesterification of soybean oil catalyzed by Sr-doped cinder

International Nuclear Information System (INIS)

Nasreen, Sadia; Liu, Hui; Khan, Romana; Zhu, Xiao-chan; Skala, Dejan

2015-01-01

Highlights: • Sr-doped cinder catalyst was prepared and used for biodiesel synthesis. • A 99% of triglycerides conversion was achieved under optimal reaction conditions. • SrAl 2 Si 2 O 8 and Sr 5 Al 8 O 1 are determined as dominant compounds which are responsible for high catalytic activity. • Catalyst exhibits high activity and can be easily recovered and regenerated. • The Sr-doped cinder catalyst is used in 14 repeated runs. - Abstract: The Strontium doped cinder was prepared using the wet impregnation method and analyzed as catalyst for biodiesel synthesis. Different procedure for cinder impregnation were investigated (temperature and duration of catalyst calcinations, the concentration of SrCl 2 solution) and optimal condition was established: impregnation 20 g of cinder 2–5 mm particles with 0.2 M SrCl 2 solution followed by calcinations at 1000 °C for 4 h. The Sr-cinder activity was tested at 90–200 °C using 1–5% mass of catalyst with different molar ratio of methanol to soybean oil (from 9 to 36). The maximum triglycerides (TG) conversion of 99.0% with the Fatty Acid Methyl Esters (FAME) yield of 97.1% was obtained by using 4% catalyst at 180 °C, for 1 h, and methanol/oil molar ratio 24:1. Influence of free fatty acid (FFA) and water in soybean oil on catalyst activity was analyzed, too. The catalyst could be used for 14 times with TG conversion and FAME yield above 90% and 80% respectively. The Sr-doped cinder catalysts before and after transesterification were characterized using BET surface area, basic strength, X-ray diffraction (XRD), scanning electron microscopy (SEM) and ICP-AAS. Results showed that the formation of SrAl 2 Si 2 O 8 and Sr 5 Al 8 O 17 complexes should be the main reason for the catalytic activity of prepared catalyst. Slow decrease of catalyst activity during its repeated use is result of Sr–Al-glycerolate formation in reaction between Sr–Al complexes and glycerol

Efficacy of the biomaterials 3 wt%-nanostrontium-hydroxyapatite-enhanced calcium phosphate cement (nanoSr-CPC) and nanoSr-CPC-incorporated simvastatin-loaded poly(lactic-co-glycolic-acid) microspheres in osteogenesis improvement: An explorative multi-phase experimental in vitro/vivo study

International Nuclear Information System (INIS)

Masaeli, Reza; Jafarzadeh Kashi, Tahereh Sadat; Dinarvand, Rassoul; Rakhshan, Vahid; Shahoon, Hossein; Hooshmand, Behzad; Mashhadi Abbas, Fatemeh; Raz, Majid; Rajabnejad, Alireza; Eslami, Hossein; Khoshroo, Kimia

2016-01-01

Aims: The purpose of this multi-phase explorative in vivo animal/surgical and in vitro multi-test experimental study was to (1) create a 3 wt%-nanostrontium hydroxyapatite-enhanced calcium phosphate cement (Sr-HA/CPC) for increasing bone formation and (2) creating a simvastatin-loaded poly(lactic-co-glycolic acid) (SIM-loaded PLGA) microspheres plus CPC composite (SIM-loaded PLGA + nanostrontium-CPC). The third goal was the extensive assessment of multiple in vitro and in vivo characteristics of the above experimental explorative products in vitro and in vivo (animal and surgical studies). Methods and results pertaining to Sr-HA/CPC: Physical and chemical properties of the prepared Sr-HA/CPC were evaluated. MTT assay and alkaline phosphatase activities, and radiological and histological examinations of Sr-HA/CPC, CPC and negative control were compared. X-ray diffraction (XRD) indicated that crystallinity of the prepared cement increased by increasing the powder-to-liquid ratio. Incorporation of Sr-HA into CPC increased MTT assay (biocompatibility) and ALP activity (P < 0.05). Histomorphometry showed greater bone formation after 4 weeks, after implantation of Sr-HA/CPC in 10 rats compared to implantations of CPC or empty defects in the same rats (n = 30, ANOVA P < 0.05). Methods and results pertaining to SIM-loaded PLGA microspheres + nanostrontium-CPC composite: After SEM assessment, the produced composite of microspheres and enhanced CPC were implanted for 8 weeks in 10 rabbits, along with positive and negative controls, enhanced CPC, and enhanced CPC plus SIM (n = 50). In the control group, only a small amount of bone had been regenerated (localized at the boundary of the defect); whereas, other groups showed new bone formation within and around the materials. A significant difference was found in the osteogenesis induced by the groups sham control (16.96 ± 1.01), bone materials (32.28 ± 4.03), nanostrontium-CPC (24.84 ± 2.6), nanostrontium-CPC-simvastatin (40

Efficacy of the biomaterials 3 wt%-nanostrontium-hydroxyapatite-enhanced calcium phosphate cement (nanoSr-CPC) and nanoSr-CPC-incorporated simvastatin-loaded poly(lactic-co-glycolic-acid) microspheres in osteogenesis improvement: An explorative multi-phase experimental in vitro/vivo study

Energy Technology Data Exchange (ETDEWEB)

Masaeli, Reza [Dental Biomaterials Department, School of Dentistry, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Jafarzadeh Kashi, Tahereh Sadat, E-mail: jafarzat@sina.tums.ac.ir [Dental Biomaterials Department, School of Dentistry, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Iranian Tissue Bank and Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Dinarvand, Rassoul [Department of Pharmaceutics, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Rakhshan, Vahid [Iranian Tissue Bank and Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Shahoon, Hossein [Department of Oral and Maxillofacial Surgery, School of Dentistry, Shahed University, Tehran (Iran, Islamic Republic of); Hooshmand, Behzad [Department of Periodontology, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Mashhadi Abbas, Fatemeh [Department of Oral and Maxillofacial Pathology, School of Dentistry, Shahid Beheshti Medical Science University, Tehran (Iran, Islamic Republic of); Raz, Majid; Rajabnejad, Alireza; Eslami, Hossein [Biomaterials Group, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Khoshroo, Kimia [Dental Biomaterials Department, School of Dentistry, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Department of Developmental Sciences, School of Dentistry, Marquette University, Milwaukee, WI (United States); and others

2016-12-01

Aims: The purpose of this multi-phase explorative in vivo animal/surgical and in vitro multi-test experimental study was to (1) create a 3 wt%-nanostrontium hydroxyapatite-enhanced calcium phosphate cement (Sr-HA/CPC) for increasing bone formation and (2) creating a simvastatin-loaded poly(lactic-co-glycolic acid) (SIM-loaded PLGA) microspheres plus CPC composite (SIM-loaded PLGA + nanostrontium-CPC). The third goal was the extensive assessment of multiple in vitro and in vivo characteristics of the above experimental explorative products in vitro and in vivo (animal and surgical studies). Methods and results pertaining to Sr-HA/CPC: Physical and chemical properties of the prepared Sr-HA/CPC were evaluated. MTT assay and alkaline phosphatase activities, and radiological and histological examinations of Sr-HA/CPC, CPC and negative control were compared. X-ray diffraction (XRD) indicated that crystallinity of the prepared cement increased by increasing the powder-to-liquid ratio. Incorporation of Sr-HA into CPC increased MTT assay (biocompatibility) and ALP activity (P < 0.05). Histomorphometry showed greater bone formation after 4 weeks, after implantation of Sr-HA/CPC in 10 rats compared to implantations of CPC or empty defects in the same rats (n = 30, ANOVA P < 0.05). Methods and results pertaining to SIM-loaded PLGA microspheres + nanostrontium-CPC composite: After SEM assessment, the produced composite of microspheres and enhanced CPC were implanted for 8 weeks in 10 rabbits, along with positive and negative controls, enhanced CPC, and enhanced CPC plus SIM (n = 50). In the control group, only a small amount of bone had been regenerated (localized at the boundary of the defect); whereas, other groups showed new bone formation within and around the materials. A significant difference was found in the osteogenesis induced by the groups sham control (16.96 ± 1.01), bone materials (32.28 ± 4.03), nanostrontium-CPC (24.84 ± 2.6), nanostrontium-CPC-simvastatin (40

How has severe accident analysis contributed to sizewell B and how can it continue to contribute in the future

International Nuclear Information System (INIS)

Harrison, J.R.; Western, D.J.

1987-01-01

Sizewell B is a proposed 1100 MWe PWR which is a UK development of the US SNUPPS design. The UK reference design document for the plant was first issued in 1981 and the Pre-Construction Safety Report (PCSR) was submitted to the Nuclear Installations Inspectorate (NII), the UK licensing authority, in 1982. A major public inquiry into the proposal took place between January 1983 and March 1985. This paper is concerned with the analysis of severe accidents. This means all the analysis that is concerned with those fault sequences that are outside the design basis of the plant and which may lead to severe consequences - either in terms of plant damage or release of radioactivity. This analysis comprises probabilistic assessments of the frequency of such sequences, transient analysis of the way such sequences develop and radiological release analysis. Part one of this paper examines how the severe accident analysis carried out for Sizewell B has contributed to the judgement that the design is sound and that the construction phase should proceed. The second part of the paper looks to the future and asks ''Can severe accident analysis make any further contribution during the period from licensing up until operation commences

System of Sr(NO2)2-Sr(OH)2-H2O at 25 deg C

International Nuclear Information System (INIS)

Popova, T.B.; Berdyukova, V.A.; Khutsistova, F.M.

1990-01-01

Sr(NO 2 ) 2 -Sr(OH) 2 -H 2 O system was investigated by the methods of solubility, density, viscosity, electric conductivity and refractometry. It was established that its compoments form the compound 4Sr(NO 2 ) 2 xSr(OH) 2 x8H 2 O. The compound was separated from solution; its density, decomposition temperature were determined; IR spectra and X-ray patterns of prepared and initial compounds were obtained

C, Sr and Sr isotopic composition on probable vendian- tommotian carbonate sequences in Nw Argentina

International Nuclear Information System (INIS)

Sial, A. N.; Ferreira, V.P; Toselli, A.J.; Acenolaza, F.G; Pimentel, M.M; Parada, M.A; Alonso, R.N

2001-01-01

C-isotope stratigraphy is one of the most powerfool tools in Precambrian chronostratigraphy, especially when sediments lack recognizable animal fossils. The δ 13 C secular variation curves for marine carbonates in the Neoproterozoic-Cambrian interval show strong positive-negative excursions, several of them interpreted as the stratigraphic position of ancient ice ages (Hoffman et al. 1998). The Sr isotope composition of the seawater for this age interval is characterized by a continuous increase of 87 Sr/ 86 Sr that is interrupted, several times, by sharp rises, which represent important changes in the Earth history (Montanez et al. 2000). Only limited data on the behavior of C and Sr isotopes in carbonates are available in South America. We examine here carbonate sequences from the Argentine Precordillera, San Juan province, and from other carbonate sequences in NW Argentina that could be, potentially, proxies for the Precambrian-Cambrian transition. We have studied their δ 13 C and 87 Sr/ 86 Sr chemostratigraphy and compare it to global C and Sr isotope secular variation curves for this time span. This study aims to improve the relatively coarse stratigraphic resolution provided only by the study of the fossil record in some of the carbonate successions under consideration (au)

Tracking selenium in the Chalk aquifer of northern France: Sr isotope constraints

International Nuclear Information System (INIS)

Cary, L.; Benabderraziq, H.; Elkhattabi, J.; Gourcy, L.; Parmentier, M.; Picot, J.; Khaska, M.; Laurent, A.; Négrel, Ph.

2014-01-01

Highlights: • We report the chemistry of the Chalk groundwater affected by Se contamination. • Strontium isotopes were used to identify the groundwater bodies and their mixings. • The spatial and temporal Se variability is mainly linked to the presence of Se-rich clays. • Saturation or desaturation of Se-rich clays control Se mobility. - Abstract: Groundwater at the southern and eastern edges of France’s Paris Basin has a selenium content that at times exceeds the European Framework Directive’s drinking-water limit value of 10 μg/L. To better understand the dynamics of the Chalk groundwater being tapped to supply the city of Lille and the Se origins, we used a combination of geochemical and isotopic tools. Strontium isotopes, coupled with Ca/Sr, Mg/Sr and Se/Sr ratios, were used to identify the main groundwater bodies and their mixings, with the Mg/Sr and Se/Sr ratios constraining a ternary system. Groundwater in the agricultural aquifer-recharge zone represents a first end-member and displays the youngest water ages of the catchment along with the highest Sr isotopic signature (0.70842) and low Se contents. Anaerobic groundwater constitutes a second major end-member affected by water-rock interactions over a long residence time, with the lowest Sr isotopic signature (0.70789) and the lowest Se content, its low SF6 content confirming the contribution of old water. Se-rich groundwater containing up to 30 μg/L of Se represents a third major end-member, with an intermediate Sr isotopic ratio (0.70826), and is mainly constrained by the clayey Se-rich formation overlying the Chalk aquifer. The spatial and temporal Se variability in the groundwater is clearly linked to the presence of this formation identified as Tertiary and also to the hydrological conditions; saturation of the Se-rich clays by oxygenated groundwater enhances Se mobility and also Sr adsorption onto the clays. This multi-tool study including Sr isotopes successfully identified the Se

Measurement of resonance integral of the 90Sr(n,γ)91Sr reaction

International Nuclear Information System (INIS)

Nakamura, Shoji; Furutaka, Kazuyoshi; Wada, Hiroaki; Katoh, Toshio; Harada, Hideo; Fujii, Toshiyuki; Yamana, Hajimu

2001-01-01

To obtain fundamental data for research on nuclear transmutation method of radioactive wastes, the resonance integral (I 0 ) of the 90 Sr(n,γ) 91 Sr reaction was measured with an activation method. (author)

Portal hypertension and liver cirrhosis in rats: effect of the β3-adrenoceptor agonist SR58611A

Science.gov (United States)

Vasina, Valentina; Giannone, Ferdinando; Domenicali, Marco; Latorre, Rocco; Berzigotti, Annalisa; Caraceni, Paolo; Zoli, Marco; De Ponti, Fabrizio; Bernardi, Mauro

2012-01-01

BACKGROUND AND PURPOSE β3-Adrenoceptors participate in the regulation of vascular tone in physiological and pathological conditions. We aimed to assess the effect of pharmacological modulation of β3-adrenoceptors on portal pressure (PP) and systemic haemodynamics and their expression in the liver and mesenteric vessels of cirrhotic rats. EXPERIMENTAL APPROACH PP, central venous pressure (CVP) and systemic haemodynamics were invasively assessed in control and CCl4-treated cirrhotic rats before and during infusion of the selective β3-adrenoceptor agonist, SR58611A. Tissue samples were also collected from liver, heart, portal vein and mesenteric artery for immunohistochemistry and molecular biology analysis. The effect of SR58611A on isolated portal vein was assessed. KEY RESULTS At baseline, cirrhotic rats showed portal hypertension, reduced CVP and hyperdynamic circulation. SR58611A induced a significant, dose-dependent decrease in PP in cirrhotic rats, but not in controls. Although both groups manifested a dose-dependent reduction in mean arterial pressure, this effect was associated with decreased cardiac index (CI) and unchanged indicized peripheral vascular resistance (PVRI) in cirrhotic rats and increased CI and decreased PVRI in control animals. Pretreatment with the selective β3-adrenoceptor antagonist SR59230 prevented all SR58611A-induced changes in cirrhotic rats. SR58611A concentration-dependently relaxed portal vein in cirrhotic rats to a significantly greater extent than in healthy rats; pretreatment with SR59230A completely prevented SR58611A-induced cirrhotic portal vein relaxation. Finally, β3-adrenoceptors were identified in the liver, heart and portal vein of cirrhotic and control animals; their expression was increased in cirrhotic rats. CONCLUSIONS AND IMPLICATIONS β3-Adrenoceptors are altered in portal hypertension of experimental cirrhosis and may represent a novel therapeutic target. PMID:22708587

Solidification of Bi2Sr2Ca1Cu2Oy and Bi2Sr1.75Ca0.25CuOy

International Nuclear Information System (INIS)

Holesinger, T.G.; Miller, D.J.; Viswanathan, H.K.; Chumbley, L.S.

1993-01-01

The solidification processes for the compositions Bi 2 Sr 2 CaCu 2 O y (2212) and Bi 2 Sr 1.75 Ca 0.25 CuO y (2201) were determined as a function of oxygen partial pressure. During solidification in argon, the superconducting phases were generally not observed to form for either composition. In both cases, the solidus is lowered to approximately 750 degree C. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 2-x Ca x O y (22x) and Cu 2 O while solidification of Bi 2 Sr 2 CaCu 2 O y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 3-x Ca x O y (23x) and Cu 2 O. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in O 2 resulted in large grains of 2201 interspersed with small regions containing the eutectic structure of 22x and CuO/Cu 2 O. Solidification of Bi 2 Sr 2 CaCu 2 O y in partial pressures of 1%, 20%, and 100% oxygen resulted in multiphase samples consisting of 2212, 2201, some alkaline-earth cuprates, and both divorced eutectic structures found during solidification in Ar. For both compositions, these latter structures can be attributed to oxygen deficiencies present in the melt regardless of the overpressure of oxygen. These eutectic structures are unstable and convert into the superconducting phases during subsequent anneals in oxygen. The formation process of the 2212 phase during solidification from the melt was determined to proceed through an intermediate state involving the 2201 phase

Onset of collectivity in $^{96,98}$Sr studied via Coulomb excitation

CERN Document Server

Clement, E; Dijon, A; de France, G; Bastin, B; Blazhev, A; Bree, N; Butler, P; Delahaye, P; Ekstrom, A; Georgiev, G; Hasan, N; Iwanicki, J; Jenkins, D; Korten, W; Larsen, A C; Ljungvall, J; Moschner, K; Napiorkowski, P; Pakarinen, J; Petts, A; Renstrom, T; Seidlitz, M; Siem, S; Sotty, C; Srebrny, J; Stefanescu, I; Tveten, G M; Van de Walle, J; Warr, N; Wrzosek-Lipska, K; Zielinska, M; Bauer, C; Bruyneel, B; Butterworth, J; Fitzpatrick, C; Fransen, C; GernhäUser, R; Hess, H; Lutter, R; Marley, P; Reiter, P; Siebeck, B; Vermeulen, M; Wiens, A; De Witte, H

2014-01-01

A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N=60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

Onset of collectivity in 96,98Sr studied via Coulomb excitation

Directory of Open Access Journals (Sweden)

Clément E.

2014-03-01

Full Text Available A rapid onset of quadrupole deformation is known to occur around the neutron number 60 in the neutron-rich Zr and Sr isotopes. This shape change has made the neutron-rich A = 100 region an active area of experimental and theoretical studies for many decades now. We report in this contribution new experimental results in the neutron rich 96,98Sr investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility, CERN. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross section supporting the scenario of shape coexistence/change at N=60. Future perspectives are presented including the recent experimental campaign performed at ILL-Grenoble.

Thermal infrared and microwave absorbing properties of SrTiO3/SrFe12O19/polyaniline nanocomposites

International Nuclear Information System (INIS)

Hosseini, Seyed Hossein; Zamani, Parisa; Mousavi, S.Y.

2015-01-01

Graphical abstract: We have developed a new perspective of applications and properties of conducting polymers. The combination of absorption ability prepared nanocomposites in the present of PANI display a great potential in organization of shielding structures into thermal IR and microwave. Further investigations using other conducting polymers to demonstrate their capability for advance thermal IR and microwave shielding devices is under way. The application of these samples may improve the IR thermographic detection, catalysis, sensors, magnetic data storage, electromagnetic resonance wave absorption, photonic crystals, and microelectronic devices and military aspects. - Highlights: • The SrTiO 3 /SrFe 12 O 19 /PANI exhibited electric and electromagnetic properties. • The SrTiO 3 /SrFe 12 O 19 /PANI has shielding structures into thermal IR and microwave. • Increasing weight ratios and thicknesses will increase thermal IR ability. • Increasing weight ratios and thicknesses will increase microwave absorption ability. - Abstract: Polyaniline (PANI) as a unique polymer that also has electromagnetic absorption used as the substrate. In this research, SrTiO 3 was synthesized as IR absorbent and core and then SrFe 12 O 19 as microwave absorbent was prepared on SrTiO 3 via co-precipitation method as the first shell. As the next step, PANI was coated on SrTiO 3 /SrFe 12 O 19 nanoparticles via in situ polymerization by multi core–shell structures (SrTiO 3 /SrFe 12 O 19 /PANI). Nanometer size and structures of samples were measured by TEM, XRD and FTIR. Morphology of nanocomposite was showed by SEM images. The magnetic and electric properties were also performed by VSM and four probe techniques. Thermal infrared (IR) absorption and microwave reflection loss of nanocomposites were investigated at 10–40 μm and 8–12 GHz, IR and microwave frequencies, respectively. The results showed that the SrTiO 3 /SrFe 12 O 19 /PANI nanocomposites have good compatible

⁸⁷Sr/⁸⁶Sr Concentrations in the Appalachian Basin: A Review

Energy Technology Data Exchange (ETDEWEB)

Mordensky, Stanley P. [Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); National Energy Technology Lab. (NETL), Albany, OR (United States); Lieuallen, A. Erin [Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); National Energy Technology Lab. (NETL), Albany, OR (United States); Verba, Circe [National Energy Technology Lab. (NETL), Albany, OR (United States); Hakala, Alexandra [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

2016-06-16

This document reviews ⁸⁷Sr/⁸⁶Sr isotope data across the Appalachian Basin from existing literature to show spatial and temporal variation. Isotope geochemistry presents a means of understanding the geochemical effects hydraulic fracturing may have on shallow ground substrates. Isotope fractionation is a naturally occurring phenomenon brought about by physical, chemical, and biological processes that partition isotopes between substances; therefore, stable isotope geochemistry allows geoscientists to understand several processes that shape the natural world. Strontium isotopes can be used as a tool to answer an array of geological and environmental inquiries. In some cases, strontium isotopes are sensitive to the introduction of a non-native fluid into a system. This ability allows strontium isotopes to serve as tracers in certain systems. Recently, it has been demonstrated that strontium isotopes can serve as a monitoring tool for groundwater and surface water systems that may be affected by hydraulic fracturing fluids (Chapman et al., 2013; Kolesar Kohl et al., 2014). These studies demonstrated that ⁸⁷Sr/⁸⁶Sr values have the potential to monitor subsurface fluid migration in regions where extraction of Marcellus Shale gas is occurring. This document reviews publicly available strontium isotope data from 39 sample locations in the Appalachian Basin (Hamel et al., 2010; Chapman et al., 2012; Osborn et al., 2012; Chapman et al., 2013; Capo et al., 2014; Kolesar Kohl et al., 2014). The data is divided into two sets: stratigraphic (Upper Devonian/Lower Mississippi, Middle Devonian, and Silurian) and groundwater. ArcMap™ (ESRI, Inc.) was used to complete inverse distance weighting (IDW) analyses for each dataset to create interpolated surfaces in an attempt to find regional trends or variations in strontium isotopic values across the Appalachian Basin. ⁸⁷Sr/⁸⁶Sr varies up to ~ 0.011 across the

The characteristics of intake Cs-137 and Sr-90 with food by Ozersk's inhabitants

International Nuclear Information System (INIS)

Dronova, M.

2000-01-01

This work is based on a questionnaire of production plant 'MAYAK' workers eating habits. Cs-137 and Sr-90 were chosen as experimental radionuclides. Cs-137 is distributed in organisms equally. It is considered to be a source of genetic damage after entry into the human body. This radionuclide is almost completely absorbed as it passes into the bowels after peroral entry. In the blood Cs-137 is distributed almost evenly between organs and tissues. It was established that Cs-137 accumulates in muscle, kidney, heart, spleen, lungs, and liver to a higher degree. Although the half-life of Cs-137 exceeds Sr-90, Cs-137 leaves the body more rapidly. The radiation dose of Cs-137 per unit of intake is less than for Sr-90. In addition, Cs-137 is absorbed by plants to a lesser degree than Sr-90. Taking into account that a considerable part of the daily diet consists of vegetables, it should be noted that different radionuclides get into plants in different amounts and different ways. Cs-137 concentrates in cereal, beans, oil plants, potatoes. beets and tomatoes. Meat and milk are also a main source of Cs-137 in a person's diet. Sr-90 contributes to radiation dose for bone and marrow, almost all Sr-90 is taken up by organisms through milk, greens, and cereal. (authors)

Long lasting yellow phosphorescence and photostimulated luminescence in Sr3SiO5 : Eu2+ and Sr3SiO5 : Eu2+, Dy3+ phosphors

International Nuclear Information System (INIS)

Sun Xiaoyuan; Zhang Jiahua; Zhang Xia; Luo Yongshi; Wang Xiaojun

2008-01-01

We report the observation of long lasting yellow phosphorescence and photostimulated luminescence (PSL) in Sr 3 SiO 5 : Eu 2+ and Sr 3 SiO 5 : Eu 2+ , Dy 3+ phosphors. The decay patterns of phosphorescence and thermoluminescence curves demonstrate that introduction of Dy 3+ into Sr 3 SiO 5 : Eu 2+ can generate a large number of shallow traps and deep traps. The generated deep traps prolong the phosphorescence up to 6 h after UV irradiation. The PSL is studied under 808 nm excitation. Slow rising and falling edges of the emission in Sr 3 SiO 5 : Eu 2+ , Dy 3+ are observed, showing a retrapping process by the generated shallow traps due to co-doping Dy 3+ .

Contribution of water chemistry and fish condition to otolith chemistry: comparisons across salinity environments.

Science.gov (United States)

Izzo, C; Doubleday, Z A; Schultz, A G; Woodcock, S H; Gillanders, B M

2015-06-01

This study quantified the per cent contribution of water chemistry to otolith chemistry using enriched stable isotopes of strontium ((86) Sr) and barium ((137) Ba). Euryhaline barramundi Lates calcarifer, were reared in marine (salinity 40), estuarine (salinity 20) and freshwater (salinity 0) under different temperature treatments. To calculate the contribution of water to Sr and Ba in otoliths, enriched isotopes in the tank water and otoliths were quantified and fitted to isotope mixing models. Fulton's K and RNA:DNA were also measured to explore the influence of fish condition on sources of element uptake. Water was the predominant source of otolith Sr (between 65 and 99%) and Ba (between 64 and 89%) in all treatments, but contributions varied with temperature (for Ba), or interactively with temperature and salinity (for Sr). Fish condition indices were affected independently by the experimental rearing conditions, as RNA:DNA differed significantly among salinity treatments and Fulton's K was significantly different between temperature treatments. Regression analyses did not detect relations between fish condition and per cent contribution values. General linear models indicated that contributions from water chemistry to otolith chemistry were primarily influenced by temperature and secondly by fish condition, with a relatively minor influence of salinity. These results further the understanding of factors that affect otolith element uptake, highlighting the necessity to consider the influence of environment and fish condition when interpreting otolith element data to reconstruct the environmental histories of fish. © 2015 The Fisheries Society of the British Isles.

New aragonite 87Sr/86Sr records of Mesozoic ammonoids and approach to the problem of N, O, C and Sr isotope cycles in the evolution of the Earth

Science.gov (United States)

Zakharov, Yuri D.; Dril, Sergei I.; Shigeta, Yasunari; Popov, Alexander M.; Baraboshkin, Eugenij Y.; Michailova, Irina A.; Safronov, Peter P.

2018-02-01

New Sr isotope data from well-preserved aragonite ammonoid shell material from the Mesozoic are compared with that from a living Nautilus shell. The prominent negative Sr isotope excursions known from the Middle Permian, Jurassic and Cretaceous probably have their origins in intensive plate tectonic activity, followed by enhanced hydrothermal activity at the mid-ocean ridges (mantle volcanism) which supplied low radiogenic Sr to seawater. The maximum positive (radiogenic) shift in the lower Mesozoic Sr isotope curve (Lower Triassic peak) was likely caused by a significant expansion of dry land surfaces (Dabie-Sulu Triassic orogeny) and their intensive silicate weathering in conditions of extreme warming and aridity in the very end of the Smithian, followed by warm and humid conditions in the late Spathian, which apparently resulted in a significant oceanic input of radiogenic Sr through riverine flux. The comparatively high 87Sr/86Sr ratio obtained from the living Nautilus shell is probably a function of both the Alpine orogeny, which was accompanied by significant continental weathering and input of radiogenic Sr to the oceans, and the weakening of mantle volcanism.

Assessment of dietary of 90Sr and 137Cs by the population of the GDR

International Nuclear Information System (INIS)

Ziesak, H.; Kunert, M.; Kunert, J.

1978-01-01

Based on data pertaining to the per caput consumption of the most important classes of foodstuffs and their contents of 90 Sr and 137 Cs, calculations were made to find out the yearly ingestion of these fallout radionuclides by the adult population in 1975. The strong decline in values of ingestion to be noticed since 1964 is due to the falling 90 Sr and 137 Cs levels in most biomedia as well as to changes in nutritional habits and allows a sensible curtailment of the foodstuff monitoring programme for radionuclides to be made. (author)

Over-expression of SR-cyclophilin, an interaction partner of nuclear pinin, releases SR family splicing factors from nuclear speckles

International Nuclear Information System (INIS)

Lin, C.-L.; Leu, Steve; Lu, M.-C.; Ouyang Pin

2004-01-01

Pre-mRNA splicing takes place within a dynamic ribonucleoprotein particle called the spliceosome and occurs in an ordered pathway. Although it is known that spliceosome consists of five small nuclear RNAs and at least 50 proteins, little is known about how the interaction among the proteins changes during splicing. Here we identify that SR-cyp, a Moca family of nuclear cyclophilin, interacts and colocalizes with nuclear pinin (pnn), a SR-related protein involving in pre-mRNA splicing. Nuclear pnn interacts with SR-cyp via its C-terminal RS domain. Upon SR-cyp over-expression, however, the subnuclear distribution of nuclear pnn is altered, resulting in its redistribution from nuclear speckles to a diffuse nucleoplasmic form. The diffuse subnuclear distribution of nuclear pnn is not due to epitope masking, accelerated protein turnover or post-translational modification. Furthermore, we find that SR-cyp regulates the subnuclear distribution of other SR family proteins, including SC35 and SRm300, in a similar manner as it does on nuclear pnn. This result is significant because it suggests that SR-cyp plays a general role in modulating the distribution pattern of SR-like and SR proteins, similar to that of Clk (cdc2-like kinase)/STY on SR family splicing factors. SR-cyp might direct its effect via either alteration of protein folding/conformation or of protein-protein interaction and thus may add another control level of regulation of SR family proteins and modification of their functions

Accumulation of 90Sr to cattle and horse bones in Hokkaido

International Nuclear Information System (INIS)

Chikayama, Yukio; Yagi, Yukio; Shiono, Hiroki; Watanabe, Atsushi; Miyamoto, Toru

1999-01-01

Since herbivores like cattle and horse take plants contaminated by radioactive fallout, 90 Sr in their bones can be a excellent biological measure of environmental radioactive pollution. The authors continued and reported such investigations on 90 Sr accumulation from 1957 and this paper described the summary from 1987 to 1996. Samples of 225 cattle bones and 257 horse bones were treated at 900 deg C for 5-6 hr. 90 Y extracted by (2-ethylhexyl)phosphoric acid from the samples was measured in the low back-ground gas-flow counter and the concentrations (mBq/g·Ca) of the parent nuclide 90 Sr were estimated. Bone level of 90 Sr, after peaked at 1965-1966, had deceased thereafter and became the minimum at 1995 in the cattle and at 1996 in the horse. Horse bones contained the higher 90 Sr level than cattle's. There was a positive correlation between the age and 90 Sr concentration. In conclusion, the environmental radioactivity due to the fallout is low at present in Hokkaido. (K.H.)

Identification of Marchfeld asparagus using Sr isotope ratio measurements by MC-ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Swoboda, S; Brunner, M; Boulyga, S F; Galler, P; Prohaska, T [University of Natural Resources and Applied Life Sciences, Department of Chemistry-VIRIS Project, Vienna (Austria); Horacek, M [Austrian Research Centers GmbH, Seibersdorf (Austria)

2008-01-15

This work focuses on testing and application of Sr isotope signatures for the fast and reliable authentication and traceability of Asparagus officinalis originating from Marchfeld, Austria, using multicollector inductively coupled plasma mass spectrometry after optimised Rb/Sr separation. The major sample pool comprises freeze-dried and microwave-digested asparagus samples from Hungary and Slovakia which are compared with Austrian asparagus originating from the Marchfeld region, which is a protected geographical indication. Additional samples from Peru, the Netherlands and Germany were limited in number and allowed therefore only restricted statistical evaluation. Asparagus samples from Marchfeld were harvested within two subsequent years in order to investigate the annual variation. The results show that the Sr isotope ratio is consistent within these 2 years of investigation. Moreover, the Sr isotope ratio of total Sr in soil was found to be significantly higher than in an NH{sub 4}NO{sub 3} extract, reflecting the mobile (bioavailable) phase. The isotope composition in the latter extract corresponds well to the range found in the asparagus samples in Marchfeld, even though the concentration of Sr in asparagus shows no direct correlation to the concentration of Sr in the mobile phase of the soil. The major question was whether the 'Marchfelder Spargel' can be distinguished from samples from the neighbouring countries of Hungary and Slovakia. According to our findings, they can be clearly (100%) singled out from the Hungarian samples and can be distinguished from the Slovakian asparagus samples with a probability of more than 80%. (orig.)

Identification of Marchfeld asparagus using Sr isotope ratio measurements by MC-ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Swoboda, S.; Brunner, M.; Boulyga, S.F.; Galler, P.; Prohaska, T. [University of Natural Resources and Applied Life Sciences, Department of Chemistry-VIRIS Project, Vienna (Austria); Horacek, M. [Austrian Research Centers GmbH, Seibersdorf (Austria)

2008-01-15

This work focuses on testing and application of Sr isotope signatures for the fast and reliable authentication and traceability of Asparagus officinalis originating from Marchfeld, Austria, using multicollector inductively coupled plasma mass spectrometry after optimised Rb/Sr separation. The major sample pool comprises freeze-dried and microwave-digested asparagus samples from Hungary and Slovakia which are compared with Austrian asparagus originating from the Marchfeld region, which is a protected geographical indication. Additional samples from Peru, the Netherlands and Germany were limited in number and allowed therefore only restricted statistical evaluation. Asparagus samples from Marchfeld were harvested within two subsequent years in order to investigate the annual variation. The results show that the Sr isotope ratio is consistent within these 2 years of investigation. Moreover, the Sr isotope ratio of total Sr in soil was found to be significantly higher than in an NH{sub 4}NO{sub 3} extract, reflecting the mobile (bioavailable) phase. The isotope composition in the latter extract corresponds well to the range found in the asparagus samples in Marchfeld, even though the concentration of Sr in asparagus shows no direct correlation to the concentration of Sr in the mobile phase of the soil. The major question was whether the 'Marchfelder Spargel' can be distinguished from samples from the neighbouring countries of Hungary and Slovakia. According to our findings, they can be clearly (100%) singled out from the Hungarian samples and can be distinguished from the Slovakian asparagus samples with a probability of more than 80%. (orig.)

89Sr and 90Sr in atmospheric precipitations in May 1986 in Bucharest-Magurele area

International Nuclear Information System (INIS)

Paunescu, N.; Vata, I.

1987-08-01

Sr-89 and Sr-90 were determined in the fallout of May 1986. The maximum values of 335 Bq/(m 2 * 6 hours) and 110 Bq/(m 2 * 6 hours) were observed at May 2 and 5. Throughout May 1986 a quantity of 860 Bq/m 2 of Sr-90 deposited from the fallout in the Bucharest -Magurele area was determined. (authors)

Multiple Scattering Analysis of Cu - K EXAFS in Bi2Sr1.5 Cu2O8+δ

International Nuclear Information System (INIS)

Roehler, J.; Cruesemann, R.

1995-01-01

We have analyzed the Cu K-EXAFS of Bi 2 Sr 1.5 Ca 1.5 Cu 2 O 8+δ using a full multiple scattering analysis in a cluster with diameter d∼ 7.6 A. The layered structure has numerous quasi one-dimensional structural elements which give rise to significant multiple scattering contributions in the EXAFS. We confirm the Sr/Ca ratio of the sample is 1:1, and one Ca atom is located close to a nominal Sr-site. At 40 K the dimpling angle in the CuO 2 -plane is found to be ≤ 3.5 . (author)

Epitaxial phase diagrams of SrTiO3, CaTiO3, and SrHfO3: Computational investigation including the role of antiferrodistortive and A -site displacement modes

Science.gov (United States)

Angsten, Thomas; Asta, Mark

2018-04-01

Ground-state epitaxial phase diagrams are calculated by density functional theory (DFT) for SrTiO3, CaTiO3, and SrHfO3 perovskite-based compounds, accounting for the effects of antiferrodistortive and A -site displacement modes. Biaxial strain states corresponding to epitaxial growth of (001)-oriented films are considered, with misfit strains ranging between -4 % and 4%. Ground-state structures are determined using a computational procedure in which input structures for DFT optimizations are identified as local minima in expansions of the total energy with respect to strain and soft-mode degrees of freedom. Comparison to results of previous DFT studies demonstrates the effectiveness of the computational approach in predicting ground-state phases. The calculated results show that antiferrodistortive octahedral rotations and associated A -site displacement modes act to suppress polarization and reduce the epitaxial strain energy. A projection of calculated atomic displacements in the ground-state epitaxial structures onto soft-mode eigenvectors shows that three ferroelectric and six antiferrodistortive displacement modes are dominant at all misfit strains considered, with the relative contributions from each varying systematically with the strain. Additional A -site displacement modes contribute to the atomic displacements in CaTiO3 and SrHfO3, which serve to optimize the coordination of the undersized A -site cation.

Can Google Trends search queries contribute to risk diversification?

Czech Academy of Sciences Publication Activity Database

Krištoufek, Ladislav

2013-01-01

Roč. 3, č. 2713 (2013), s. 1-5 ISSN 2045-2322 R&D Projects: GA ČR GA402/09/0965 Institutional support: RVO:67985556 Keywords : Google Trends * diversification * portfolio Subject RIV: AH - Economics Impact factor: 5.078, year: 2013 http://library.utia.cas.cz/separaty/2013/E/kristoufek-can google trends search queries contribute to risk diversification.pdf

87Sr/86Sr ratios in hydrothermal waters and deposits from the east pacific rise at 210N

International Nuclear Information System (INIS)

Albarede, F.; Michard, A.; Minster, J.F.; Michard, G.

1981-01-01

87 Sr/ 86 Sr ratios of three hydrothermal waters collected on the East Pacific Rise at 21 0 N define a mixing line between seawater and a hydrothermal end-member at 0.7030 which is derived by seawater-basalt interaction at ca. 350 0 C and water/rock ratio of about 1.5. Sr concentrations are not affected in the process while Mg uptake from seawater is almost complete. Up to 2/3 of this hydrothermal component is involved in anhydrite precipitation while the Sr isotopic ratio in sulfides (chalcopyrite + sphalerite) cannot be distinguished from that of sulfate. It is estimated that ca. 1 x 10 10 moles of strontium are yearly cycled in the hydrothermal systems of mid-oceanic ridges, thereby affecting the 87 Sr/ 86 Sr budget of seawater. Mass balance between river runoff, limestone precipitation and ridge basalt alteration suggests that the 87 Sr/ 86 Sr ratios of the river runoff are in the range 0.7097-0.7113, and are largely dominated by limestone alteration. (orig.)

Synthetic clay excels in 90Sr removal

International Nuclear Information System (INIS)

Komarneni, Sridhar; Kodama, Tatsuya; Paulus, William J.; Carlson, C.

2000-01-01

Tests with actual ground water from Hanford site, and fundamental studies of 2Na + →Sr 2+ exchange equilibria revealed that a synthetic clay is extremely selective for 90 Sr with a high capacity for uptake. Comparative studies with existing Sr selective ion exchangers clearly revealed that the present synthetic clay exhibited the best performance for 90 Sr removal from actual ground water collected from three different locations at Hanford. This novel Sr ion sieve is expected to be useful for the decontamination of the environment after accidental release and contamination with 90 Sr. (c) 2000 Materials Research Society

The influence of Sr on the microstructure, degradation and stress corrosion cracking of the Mg alloys - ZK40xSr.

Science.gov (United States)

Chen, Lianxi; Bin, Yuanhong; Zou, Wenqi; Wang, Xiaojian; Li, Wei

2017-02-01

In the present work, new magnesium (Mg) alloys (Mg-4Zn-0.6Zr-xSr, x=0, 0.4, 0.8, 1.2, 1.6wt%; ZK40xSr) were prepared and studied as potential biodegradable materials. The influence of strontium (Sr) addition on the properties of the new Mg alloys was investigated, which included microstructure, corrosion degradation, and the stress corrosion cracking (SCC) susceptibility. The average grain size of the ZK40Sr was approximately 100µm, which was significantly smaller than that of ZK40 alloy without Sr (402.3±40.2µm). The size of grain boundaries precipitates in the ZK40xSr alloys gradually increased with the increase of Sr content. The grain boundaries finally showed a continuously distribution and net-like shape. The degradation test showed that the average degradation rate of the ZK40xSr alloys increased with the increase of Sr addition. In the case of Mg-4Zn-0.6Zr, the degradation rate was 2.2mgcm -2 day -1 , which was lower than that of Mg-4Zn-0.6Zr-1.6Sr (4.93mgcm -2 day -1 ). When the ZK40xSr alloys were immersed in m-SBF, the rod-like Sr-contained hydroxyapatite (HA) substance was detected, which was known to enhance cell growth around bone implants. The fracture surfaces of the as-cast Mg-4Zn-0.6Zr-1.6Sr were shown intergranular stress corrosion cracking (IGSCC) patterns. The increase of SCC susceptibility of the higher Sr ZK40xSr alloys was attributed to the increase of micro-galvanic corrosion between the α-Mg and the grain boundaries precipitates. The SCC susceptibility values were ≈0.13 and ≈0.41 for the Mg-4Zn-0.6Zr-0.4Sr and the Mg-4Zn-0.6Zr-1.6Sr, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Astronomically-Forced Lake Expansion and Contraction Cycles: Sr Isotopic Evidence from the Eocene Green River Formation, Western USA

Science.gov (United States)

Baddouh, M.; Meyers, S. R.; Carroll, A.; Beard, B. L.; Johnson, C.

2014-12-01

87Sr/86Sr ratio from ancient lake deposits offer a unique insight into the astronomical forcing of lake expansion and contraction, by recording changes in runoff/groundwater provenance. We present new high-resolution 87Sr/86Sr data from the upper Wilkins Peak Member, to investigate linkages between astronomical forcing, water sources, and lake level in a classic rhythmic succession. Fifty-one 87Sr/86Sr ratios from White Mountain core #1 were acquired with a sampling interval of ~30 cm starting from the top of alluvial "I" bed to the lower Laney Member. The 87Sr/86Sr data show a strong and significant negative correlation with oil-yield, a traditional proxy for paleolake level and organic productivity. Application of a radioisotopic time scale, using previously dated ash beds, reveals that both 87Sr/86Sr and oil yield have a strong 20 kyr rhythm. The 87Sr/86Sr data more clearly express a longer period 100 kyr signal, similar to the Laskar 10D eccentricity solution. Using our nominal radioisotopic time scale, the Laskar 10D solution and 87Sr/86Sr data suggest that highest lake levels and greatest organic enrichment are attained during greatest precession and eccentricity. Regional geologic studies and modern river water analyses have shown that less radiogenic waters mostly originate west of the basin, where drainage is strongly influenced by thick Paleozoic and Mesozoic marine carbonate units. Decreased in 87Sr/86Sr therefore imply greater relative water contributions from the Sevier orogenic highlands, relative to lower relief, more radiogenic ranges lying to the east. We therefore propose that highstands of Lake Gosiute record increased penetration of Pacific moisture, related either to increased El Niño frequency or southward displacement of major storm tracks. We hypothesize that the occurrence of wetter winters caused expansion of Lake Gosiute, deposition of organic carbon rich facies, and decreased lake water 87Sr/86Sr.

Enthalpies of formation of Cd0.917Sr0.083, Cd0.857Sr0.143 and Cd0.667Sr0.333 intermetallic compounds

International Nuclear Information System (INIS)

Agarwal, Renu; Singh, Ziley

2008-01-01

Cadmium is expected to be the solvent for pyrochemical processing of the metallic nuclear fuel. Therefore, thermodynamic properties of cadmium with various fuel and clad elements are of interest. Enthalpies of formation of the intermetallic compounds of Cd-Sr system, Cd 0.917 Sr 0.083 , Cd 0.857 Sr 0.143 and Cd 0.667 Sr 0.333 were determined by precipitation using Calvet calorimeter. Enthalpies of formation of the compounds were found to be -3.05 ± 0.5 kJ mol -1 at 723 K, -14.2 ± 0.7 kJ mol -1 at 843 K and -28.4 ± 0.8 kJ mol -1 at 863 K, respectively. Enthalpies of formation of Cd 0.917 Sr 0.083 and Cd 0.857 Sr 0.143 were also determined by partial enthalpy of formation measurements and the values were found to be -3.9 ± 1.1 kJ mol -1 at 723 K and -13.42 ± 1.2 kJ mol -1 at 843 K, respectively. Miedema model was used to estimate the enthalpies of formation of these compounds and the estimated values were compared with the experimentally determined values

Oxygen vibrations in the series Bi2Sr2Ca{_{n-1}}Cu{n}O{_{4+2 n+y}}

Science.gov (United States)

Faulques, E.; Dupouy, P.; Lefrant, S.

1991-06-01

We present a discussion of the oxygen vibrations in the Bi{2}Sr{2}Ca{n-1}Cu{n}O{4+2 n+y} high T_c superconductors with the aim of interpreting Raman spectra in the case of the non-symmorphic Amaa structure. Group theory shows that the oxygen atoms belonging to the central CuO{2} plane generate a Raman activity for the n=1,3 phases. Consequently, we propose a novel assignment for the lines of weak intensity at 297, 316 and 333 cm^{-1}. It is shown that the two components of the 460 cm^{-1} band may be consistent with the Amma structure. Spectra recorded in crossed polarization exhibit weak lines which could be assigned to B {1g} modes expected for the three phases. Nous présentons une discussion sur les vibrations des atomes d'oxygène dans la série des supraconducteurs Bi{2}Sr{2}Ca{n-1}Cu{n}O{4+2 n+y} dans le but d'interpréter les spectres Raman. L'analyse des modes normaux de vibration de la structure Amaa pour les phases n=1 ou 3 montre que les atomes d'oxygène du plan CuO{2} contenant les centres d'inversion donnent lieu à une activité Raman. En conséquence, nous proposons une nouvelle attribution pour les raies de faible intensité à 297, 316 et 333 cm^{-1}. Nous montrons que le dédoublement de la bande à 460 cm^{-1} pourrait être dû à la structure Amaa. Les spectres enregistrés en polarization croisée montrent de faibles bandes qui peuvent être attribuées aux modes B {1g} attendus pour les trois phases.

Thermodynamic Modeling of Sr/TRU Removal

International Nuclear Information System (INIS)

Felmy, A.R.

2000-01-01

This report summarizes the development and application of a thermodynamic modeling capability designed to treat the Envelope C wastes containing organic complexants. A complete description of the model development is presented. In addition, the model was utilized to help gain insight into the chemical processes responsible for the observed levels of Sr, TRU, Fe, and Cr removal from the diluted feed from tank 241-AN-107 which had been treated with Sr and permanganate. Modeling results are presented for Sr, Nd(III)/Eu(III), Fe, Cr, Mn, and the major electrolyte components of the waste (i.e. NO 3 , NO 2 , F,...). On an overall basis the added Sr is predicted to precipitate as SrCO 3 (c) and the MnO 4 - reduced by the NO 2 - and precipitated as a Mn oxide. These effects result in only minor changes to the bulk electrolyte chemistry, specifically, decreases in NO 2 - and CO 3 2- , and increases in NO 3 - and OH - . All of these predictions are in agreement with the experimental observations. The modeling also indicates that the majority of the Sr, TRU's (or Nd(III)/Eu(III)) analogs, and Fe are tied up with the organic complexants. The Sr and permanganate additions are not predicted to effect these chelate complexes significantly owing to the precipitation of insoluble Mn oxides or SrCO 3 . These insoluble phases maintain low dissolved concentrations of Mn and Sr which do not affect any of the other components tied up with the complexants. It appears that the removal of the Fe and TRU'S during the treatment process is most likely as a result of adsorption or occlusion on/into the Mn oxides or SrCO 3 , not as direct displacement from the complexants into precipitates. Recommendations are made for further studies that are needed to help resolve these issues

Elemental and isotopic (C, O, Sr, Nd) compositions of Late Paleozoic carbonated eclogite and marble from the SW Tianshan UHP belt, NW China: Implications for deep carbon cycle

Science.gov (United States)

Zhu, Jianjiang; Zhang, Lifei; Lü, Zeng; Bader, Thomas

2018-03-01

Subduction zones are important for understanding of the global carbon cycle from the surface to deep part of the mantle. The processes involved the metamorphism of carbonate-bearing rocks largely control the fate of carbon and contribute to local carbon isotopic heterogeneities of the mantle. In this study, we present petrological and geochemical results for marbles and carbonated eclogites in the Southwestern Tianshan UHP belt, NW China. Marbles are interlayered with coesite-bearing pelitic schists, and have Sr-Nd isotopic values (εNd (T=320Ma) = -3.7 to -8.9, 87Sr/86Sr (i) = 0.7084-0.7089), typical of marine carbonates. The marbles have dispersed low δ18OVSMOW values (ranging from 14 to 29‰) and unaffected carbon isotope (δ13CVPDB = -0.2-3.6‰), possibly due to infiltration of external H2O-rich fluids. Recycling of these marbles into mantle may play a key role in the carbon budget and contributed to the mantle carbon isotope heterogeneity. The carbonated eclogites have high Sr isotopic compositions (87Sr/86Sr (i) = 0.7077-0.7082) and positive εNd (T = 320 Ma) values (from 7.6 to 8.2), indicative of strong seafloor alteration of their protolith. The carbonates in the carbonated eclogites are mainly dolomite (Fe# = 12-43, Fe# = Fe2+/(Fe2+ + Mg)) that were added into oceanic basalts during seafloor alteration and experienced calcite - dolomite - magnesite transformation during the subduction metamorphic process. The uniformly low δ18O values (∼11.44‰) of carbonates in the carbontaed eclogites can be explained by closed-system equilibrium between carbonate and silicate minerals. The low δ13C values (from -3.3 to -7.7‰) of the carbonated eclogites most likely reflect contribution from organic carbon. Recycling of these carbonated eclogites with C isotope similar to typical mantle reservoirs into mantle may have little effect on the mantle carbon isotope heterogeneity.

Laser ablation inductively coupled plasma mass spectrometry. An alternative technique for monitoring 90Sr

International Nuclear Information System (INIS)

TsingHai Wang; Yan-Chen Lai; Yi-Kong Hsieh; Chu-Fang Wang

2017-01-01

Developing a rapid detection method for monitoring released 90 Sr remains a challenge to analytical chemists, particularly considering its low concentration and significant interferences in environmental samples. We proposed a concept as an alternative to detect 90 Sr on the surface of fish scales using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The high affinity of fish scales to Sr is capable of preconcentrating 90 Sr that minimizes isobaric interferences from 90 Zr + or 89 YH + , while tailing effect by abundant 88 Sr can be effectively reduced by adjusting the forward power of ICP-MS component. Adopting dried droplets of internal standards further allows a semiquantification of 90 Sr content on the surface of fish scales, which also arises an opportunity to monitoring the bioaccumulation of 90 Sr after Fukushima Daiichi nuclear disaster. (author)

Modulation of X ray DNA damage by SR-2508 +/- buthionine sulfoximine

International Nuclear Information System (INIS)

Kinsella, T.J.; Dobson, P.P.; Russo, A.; Mitchell, J.B.; Fornace, A.J. Jr.

1986-01-01

It has been demonstrated that glutathione (GSH) depletion with buthionine sulfoximine (BSO) potentiates SR-2508 radiosensitization in hypoxic cells. We have measured the effect of SR-2508 alone, BSO alone, and combined treatment on radiation-induced DNA strand breaks in hypoxic V79 cells using alkaline and neutral elution. DNA base damage recognized by a damage specific endonuclease from M. luteus was also studied. Hypoxic irradiation markedly reduces the efficiency of single-strand (SSB) and double-strand breaks (DSB) to 10-20% compared to oxic irradiation. Hypoxia had less effect on the efficiency of base damage (ESS). BSO treatment alone, resulting in GSH depletion to less than 5% of controls, had little effect of hypoxic-SSB, DSB, and ESS. SR-2508 (5 mM) treatment alone in hypoxic cells increased the number of SSB, DSB and ESS to approximately half of that resulting from oxic irradiation. However, the combination of BSO and SR-2508 in hypoxic cells resulted in SSB and DSB comparable to oxic irradiation. This combined treatment resulted in less effect on ESS. We conclude that the observed hypoxic radiosensitization, using clonogenic survival assays with combined BSO-SR-2508, correlates with our results assessing DNA strand breaks and base damage

Preparation and crystal structure of SrCu/sub 2/Sb/sub 2/ and SrZnBi/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Cordier, G; Eisenmann, B; Schaefer, H [Technische Hochschule Darmstadt (Germany, F.R.). Fachbereich Anorganische Chemie und Kernchemie

1976-10-01

SrCu/sub 2/Sb/sub 2/ and SrZnBi/sub 2/ have been prepared and analytically and structurally characterized. SrCu/sub 2/Sb/sub 2/ crystallizes tetragonal in the CaBe/sub 2/Ge/sub 2/ structure type. SrZnBi/sub 2/ has its own structure type. In both structures the transition metal atoms form with the semimetal atoms tetragonal pyramids, which are connected by common edges of the basis to twodimensional sheets. These sheets are separated in the case of SrCu/sub 2/Sb/sub 2/ by single sheets of strontium atoms, in the case of SrZnBi/sub 2/ by double sheets of strontium atoms in which fourfold nets of Bi atoms are located.

Spectroscopic and electric dipole properties of Sr+Ar and SrAr systems including high excited states

Science.gov (United States)

Hamdi, Rafika; Abdessalem, Kawther; Dardouri, Riadh; Al-Ghamdi, Attieh A.; Oujia, Brahim; Gadéa, Florent Xavier

2018-01-01

The spectroscopic properties of the fundamental and several excited states of Sr+Ar and SrAr, Van der Waals systems are investigated by employing an ab initio method in a pseudo-potential approach. The potential energy curves and the spectroscopic parameters are displayed for the 1-10 2Σ+, 1-6 2Π and 1-3 2Δ electronic states of the Sr+Ar molecule and for the 1-6 1Σ+, 1-4 3Σ+, 1-3 1,3Π and 1-3 1,3Δ states of the neutral molecule SrAr. In addition, from these curves, the vibrational levels and their energy spacing are deduced for Σ+, Π and Δ symmetries. The spectra of the permanent and transition dipole moments are studied for the 1,3Σ+ states of SrAr, which are considered to be two-electron systems and 2Σ+ states of the single electron Sr+Ar ion. The spectroscopic parameters obtained for each molecular system are compared with previous theoretical and experimental works. A significant correlation revealed the accuracy of our results.

Characteristics of Un doped and Europium-doped SrI2 Scintillator Detectors

International Nuclear Information System (INIS)

Sturm, Benjamin; Cherepy, Nerine; Drury, Owen; Thelin, P.; Fisher, S.E.; O'Neal, S.P.; Payne, Stephen A.; Burger, Arnold; Boatner, Lynn A.; Ramey, Joanne Oxendine; Shah, Kanai; Hawrami, Rastgo

2012-01-01

High energy resolution gamma-ray detectors that can be formed into relatively large sizes while operating at room temperature offer many advantages for national security applications. We are working toward that goal through the development of SrI 2 (Eu) scintillator detectors, which routinely provide ;10 cm 3 . In this study, we have tested pure, undoped SrI 2 to gain a better understanding of the scintillation properties and spectroscopic performance achievable without activation. An undoped crystal grown from 99.999% pure SrI 2 pellets was tested for its spectroscopic performance, its light yield, and uniformity of scintillation light collection as a function of gamma-ray interaction position relative to the crystal growth direction. Undoped SrI 2 was found to provide energy resolution of 5.3% at 662 keV, and the light collection nonuniformity varied by only 0.72% over the length of the crystal. Measurements of both a 3% Eu-doped and the undoped SrI 2 crystal were carried out in the SLYNCI facility and indicate differences in their light yield non-proportionality. The surprisingly good scintillation properties of the pure SrI 2 crystal suggests that with high-purity feedstock, further reduction of the Eu concentration can be made to grow larger crystals while not adversely impacting the spectroscopic performance.

The radiogenic and stable Sr isotope geochemistry of basalt weathering in Iceland: Role of hydrothermal calcite and implications for long-term climate regulation

Science.gov (United States)

Andrews, M. Grace; Jacobson, Andrew D.

2017-10-01

Several studies have examined the geochemistry of Icelandic rivers to quantify the relationship between basalt weathering and long-term climate regulation. Recent research has suggested that the chemical weathering of hydrothermal and metamorphic calcite contributes significant quantities of HCO3- to the Icelandic riverine flux (Jacobson et al., 2015). Because the HCO3- derives from volcanic CO2 that was sequestered in mineral form prior to atmospheric injection, the strength of the basalt weathering feedback occurring in Iceland may be lower than previously realized. To test these hypotheses, we analyzed the radiogenic and stable Sr isotope composition (87Sr/86Sr and δ88/86Sr) of the same suite of water, rock, and mineral samples as examined in Jacobson et al. (2015), and we developed a simple model of the long-term C cycle that considers the transformation of volcanic CO2 to HCO3- during subsurface silicate weathering, which is a precursor to hydrothermal calcite formation. Interpretations based on 87Sr/86Sr and Ca/Sr ratios suggest that conservative, three-component mixing between basalt, calcite, and atmospheric deposition adequately explains river geochemistry. On average, the δ88/86Sr values of glacial and non-glacial rivers (0.414‰ and 0.388‰, respectively) are generally higher than those for basalt (0.276‰); however, calcite δ88/86Sr values (0.347‰) are also higher than those for basalt and span the range of riverine values. Thus, riverine δ88/86Sr values are also consistent three-component mixing between basalt, calcite, and atmospheric deposition. Isotopic fractionation is not required to explain riverine trends. Finally, model equations for the long-term C cycle demonstrate that subsurface silicate weathering reduces the magnitude of the volcanic CO2 degassing flux, which in turn causes the atmosphere to stabilize at lower pCO2 values compared to the case where no subsurface silicate weathering occurs. However, the proportion of the net

Comments on geochemical aspects of SR 97

International Nuclear Information System (INIS)

Arthur, R.C.; Wei Zhou

2000-01-01

The Swedish Government has asked SKB to carry out a safety assessment of the KBS-3 disposal concept for spent nuclear fuel 'to demonstrate that the KBS-3 method has good prospects of being able to meet the safety and radiation protection requirements which SKI and SSI have specified in recent years.' The results of that assessment, referred to as SR 97, have recently been published. The present report summarizes the results of a review of selected geochemical aspects of SR 97. These subjects include the hydrochemical evolution of a defective canister, thermodynamic data supporting estimates of radioelement solubilities, modeling of near-field chemistry and analyses of the effects of ice melting on propagation of an oxidizing front to repository depths. The primary focus of the review is on the canister-defect scenario, and, more specifically, on supporting analyses of the hydromechanical evolution of a defective canister. The results of these analyses figure prominently in the safety assessment because they suggest that even a defective canister will, in effect, remain dry for as long as 200,000 years. This is an important constraint because it is taken in SR 97 as the period of time required for a continuous water pathway to form in the near field. The transport of most radionuclides (i.e., those that do not exist as a gas) cannot occur until this pathway is formed. It is concluded that although SKBs hydromechanical models are sound, they may suffer from an over-simplification of the chemical processes involved. Analyses using the models do not acknowledge that the chemical system within the canister is open in all respects to the chemical system in the buffer. Instead, mass transfer across the defect at the canister-buffer interface is limited to liquid H 2 O and water vapor. Consideration of mass transfer of other gases [e.g., CO 2 and H 2 S] dissolved in buffer porewaters suggests that associated reactions involving the iron insert and inner surfaces of the

Evidence of three-body correlation functions in Rb+ and Sr2+ acetonitrile solutions

Science.gov (United States)

D'Angelo, P.; Pavel, N. V.

1999-09-01

The local structure of Sr2+ and Rb+ ions in acetonitrile has been investigated by x-ray absorption spectroscopy (XAS) and molecular dynamics simulations. The extended x-ray absorption fine structure above the Sr and Rb K edges has been interpreted in the framework of multiple scattering (MS) formalism and, for the first time, clear evidence of MS contributions has been found in noncomplexing ion solutions. Molecular dynamics has been used to generate the partial pair and triangular distribution functions from which model χ(k) signals have been constructed. The Sr2+ and Rb+ acetonitrile pair distribution functions show very sharp and well-defined first peaks indicating the presence of a well organized first solvation shell. Most of the linear acetonitrile molecules have been found to be distributed like hedgehog spines around the Sr2+ and Rb+ ions. The presence of three-body correlations has been singled out by the existence of well-defined peaks in the triangular configurations. Excellent agreement has been found between the theoretical and experimental data enforcing the reliability of the interatomic potentials used in the simulations. These results demonstrate the ability of the XAS technique in probing the higher-order correlation functions in solution.

How can toxicogenomics inform risk assessment?

International Nuclear Information System (INIS)

Oberemm, Axel; Onyon, Lesley; Gundert-Remy, Ursula

2005-01-01

Technologies that generate information about the genome are being used to explore changes in gene expression and related proteins following exposure to chemicals. Conceptually, this information allows a greater understanding of genomic level mRNA expression (transcriptomics), cell and tissue protein expression (proteomics) and information about metabolite profiles (metabonomics). Having a greater understanding of this information alongside, empirical toxicological reference data provide for the continued evolution in our ability to understand toxicological modes of action, thereby providing a more scientific basis for extrapolation of toxicological information from animals to humans. Toxicogenomics also provides specific opportunities for improvements at different stages of the risk assessment process such as the development of new predictive models for identifying human health hazards and the identification of more precise molecular biomarkers of exposure. One possibility is that molecular fingerprinting in vivo or in vitro can be used to categorize chemicals and mixtures of chemicals into different mode of action groups. As there is indication that molecular signals differ at dose levels, it is hoped that toxicogenomic information can also contribute to the understanding and interpretation of effects seen with low dose exposure. Several gene polymorphisms have already been identified which play a role in the differing intra-species response to chemicals thus providing explanation for the observed differences in effects. It is therefore likely that a better understanding of genomic expression will enable a greater insight into the factors behind the observed variability in susceptibility to chemical exposure that can be seen in human populations

Symposium 20 - PABMB: Teaching biochemistry in a connected world: How Apps-Embedded Assessment can contribute to learning outcomes mapping

Directory of Open Access Journals (Sweden)

Eduardo Galembeck

2015-08-01

Full Text Available Symposium 20 - PABMB: Teaching biochemistry in a connected world Chair: Miguel Castanho, Universidade de Lisboa, PortugalAbstract:Apps can be designed to provide usage data, and most of them do. These usage data are usually used to map users interests and to deliver more effective ads that are more likely to result in clicks, and sales. We have applied some of these metrics to understand how it can be used to map students’ behavior using educational software. We tested both Google Analytics, and a system we have developed to map learning outcomes and students engagement. Embedded assessment were implemented in app used to teach: 1 Metabolic Pathways; 2 Protein Synthesis, 3 Cell Structure, and 4 Concepts from techniques used in a Biochemistry Lab course. Our preliminary results show that this approach provides valuable information about class outcomes that can be used for both summative and formative assessments.

87Sr/86Sr ratios in permo-carboniferous sea water from the analyses of well-preserved brachiopod shells

International Nuclear Information System (INIS)

Popp, B.N.; Anderson, T.F.

1986-01-01

Sr isotopic analyses of well-preserved portions of Permo-Carboniferous brachiopods distributed globally confirm the general shape of the Sr isotope age curve established by previous workers for this time interval. There is little variation between the SR isotopic composition of unaltered portions of brachiopods and that of portions of the same shell interpreted to be diagenetically altered (based on cathodoluminescence, elemental, and stable isotopic data). However, the Sr isotopic composition in diagenetically altered micritic matrix adjacent to the shell is more radiogenic. The Sr isotopic composition in the unaltered portions of calcitic megafossils has potential as a stratigraphic tool. (author)

Determination of Sr-90 in environmental samples using solid phase extraction disk

International Nuclear Information System (INIS)

Zal U'yun Wan Mahmood

2002-01-01

A method is described for determination of Sr-90 in environmental samples using solid phase extraction disk (Empore TM Strontium Rad Disk) and GM counter. To determine the optimum condition for capacity of Empore TM Strontium Rad Disk, its characterization studies such as the effects Sr content, acidity (molarity) of acids, presence of Ca 2+ and other major ions (Na + , Mg 2+ etc), influence of interference (Pb and Bi) and others were carried out. An optimized the using of Empore TM Strontium Rad Disk for determination of Sr-90 was validated by application to environmental samples. Quantitative recoveries above 95%for Sr (stable) were recorded in 6M HCl condition. Typical environmental samples may contain an assortment of anionic and cationic species, but in general, Empore TM Strontium Rad Disk has enough capacity to effectively separate Sr for wide variety of aqueous solutions. Sr recovery in a matrix-free or the content of matrix less than 300 mg/sample is typically greater than 99% is reported in this research work. In particular, sample, which may contain interference such as Pb and Bi would require an addition separation step before processing to ensure an accurate measurement of Sr. In this research work, radiotracer 85 Sr was used to monitor the behavior of Sr and calculation its recovery. For analytical methods that can count Y-90, the Sr-90 activity/concentration in environmental sample was calculated. The concentration of Sr-90 in ash sample (Quality Controled Sample) of 276 ± 18 Bq/kg ash was determined from Y-90 activity. The relative percent difference of 1.1% was achievable for Empore TM Sr-Rad Disk methods when compared to the conventional method (fumed-HNO 3 method) - 279 ± 11 Bq/kg ash. (Author)

Cerenkov Counter for In-Situ Groundwater Monitoring of 90Sr

Directory of Open Access Journals (Sweden)

Lindsay C. Todd

2005-02-01

Full Text Available Groundwater contamination from 90Sr is an environmental challenge posed topresent and former nuclear weapons related sites. Traditional methods of extractinggroundwater samples and performing laboratory analyses are expensive, time-consumingand induce significant disposal challenges. The authors present here a prototype countercapable of measuring 90Sr groundwater concentrations in-situ at or below the drinking waterlimit of 8 pCi/liter. The 90Y daughter of 90Sr produces high-energy electrons, which cancreate Cerenkov light. Photomultiplier tubes convert the Cerenkov light into an electronicpulse, which then undergoes signal processing with standard electronics. Strontium-90concentrations near the drinking water limit can be measured in a matter of hours if it is insecular equilibrium with the 90Y daughter. The prototype counter is compact, can bedeployed in an American Standard 6-inch, well while operated by a single person, andtransmits the results to a central monitoring location.

IFC Jobs Study : Assessing Private Sector Contributions to Job Creation and Poverty Reduction

OpenAIRE

International Finance Corporation

2013-01-01

This report is the result of an open-source study to assess the direct and indirect effects of private sector activity on job creation. The report examines how and under what conditions the private sector can best contribute to job creation and poverty reduction. The private sector, which provides some 90 percent of jobs in developing countries, must be at the core of any response to this ...

Energy consumption in smelting reduction (SR) processes

International Nuclear Information System (INIS)

Assis, Paulo Santos; Salierno, Giovanni Felice; Fang, Jue; Mankhand, Tilak R.; Assis, Carlos Frederico Campos de

2010-01-01

In contrast, conventional processes use coke and hematite/sinter in the blast furnace, in SR processes, other alternative fuels and iron ore sources, like charcoal and fine iron ores, can be used to produce sponge iron. The use of these alternative sources, by SR processes, can reduce environmental impacts and lower production costs. At first, the concepts of the theoretical gas utilization ratio, the smelting heat of the iron ore and the effective calorific value of coal were introduced. Then, the reason for gas utilization ratio and its performance in the shaft as a reducer in the smelting process are discussed and calculated. The relationship between coal consumption and iron ore reduction in the fluidized bed are also discussed. Finally, the influence of post-combustion on coal consumption in an iron bath furnace are calculated and discussed. (author)

A study of the formation processes of the 2212 phase in the Bi-based superconductor systems. [BiSrCaCuO

Energy Technology Data Exchange (ETDEWEB)

Wai, Lo; Glowacki, B A [Interdisciplinary Research Centre in Superconductivity, Univ. of Cambridge (United Kingdom)

1992-04-15

A study towards the identification of the reactions contributing to and accompanying the formation of the 2212 phase from oxides and carbonates by solid state reaction processes was conducted. The formation processes were investigated by thermal analysis, powder X-ray diffractometry and AC magnetic susceptometry. The 2212 phase was found to form from reactions between the 2201 phases (the non-superconducting pseudo-tetragonal and the superconducting monoclinic phases), Bi{sub 6}Ca{sub 7}O{sub 16}, CuO and SrCO{sub 3}. The 2201 phases were produced by the reactions of Bi-Sr-Cu-O or Bi-Sr-O compounds with SrCO{sub 3} or CuO. The 2201 phases could also be formed through the direct reaction between Bi{sub 2}CuO{sub 4} and SrCO{sub 3}. (orig.).

Determination of 90Sr in radioactive liquid waste-a comparative study using 'SrCO3 precipitation, extraction chromatography and Cerenkov radiation counting' techniques

International Nuclear Information System (INIS)

Mani, A.G.S.; Renganathan, K.; Rao, S.V.S.; Sinha, P.K.

2007-01-01

In the wastes generated at nuclear power plants, 90 Sr and 90 Y are responsible for approximately 7% and 38% of the total fission product activity after 1 year and 10 years respectively. Monitoring of the liquid waste produced in nuclear facilities for 90 Sr before and after releasing to the aquatic environment is essential, as it can cause a long term biological hazard due to its chemical similarity with Ca, high fission yield (5.9%) and long radioactive and biological half lives of 28 and 49.3 years respectively. As conventional carbonate precipitation method for 90 Sr- 90 Y estimation is laborious and time consuming, the other methods like extraction chromatography technique using strontium selective crown ether and Cerenkov radiation counting by liquid scintillation analyser (LSA) were also investigated. This paper describe procedures involved in the estimation of strontium in low-level radioactive liquid effluent by using above methods and deals with the comparison of results. Cerenkov radiation counting by LSA has an edge over the other methods in the determination of 90 Sr as it is a simple and rapid technique. Experiences gained in the estimation of 90 Sr in low-level radioactive liquid effluent using Cerenkov radiation counting technique is discussed in detail in this paper. (author)

Can the Future EnMAP Mission Contribute to Urban Applications? A Literature Survey

Directory of Open Access Journals (Sweden)

Andreas Müller

2011-08-01

Full Text Available With urban populations and their footprints growing globally, the need to assess the dynamics of the urban environment increases. Remote sensing is one approach that can analyze these developments quantitatively with respect to spatially and temporally large scale changes. With the 2015 launch of the spaceborne EnMAP mission, a new hyperspectral sensor with high signal-to-noise ratio at medium spatial resolution, and a 21 day global revisit capability will become available. This paper presents the results of a literature survey on existing applications and image analysis techniques in the context of urban remote sensing in order to identify and outline potential contributions of the future EnMAP mission. Regarding urban applications, four frequently addressed topics have been identified: urban development and planning, urban growth assessment, risk and vulnerability assessment and urban climate. The requirements of four application fields and associated image processing techniques used to retrieve desired parameters and create geo-information products have been reviewed. As a result, we identified promising research directions enabling the use of EnMAP for urban studies. First and foremost, research is required to analyze the spectral information content of an EnMAP pixel used to support material-based land cover mapping approaches. This information can subsequently be used to improve urban indicators, such as imperviousness. Second, we identified the global monitoring of urban areas as a promising field of investigation taking advantage of EnMAP’s spatial coverage and revisit capability. However, owing to the limitations of EnMAPs spatial resolution for urban applications, research should also focus on hyperspectral resolution enhancement to enable retrieving material information on sub-pixel level.

87Sr/86Sr in gypsic soils of hyperarid settings as an altitude proxy: results for northern Chile (19-22°S) and paleoaltimetry applications

Science.gov (United States)

Cosentino, N. J.; Jordan, T. E.; Derry, L. A.

2012-12-01

localized. Also, field studies that use 'fog-catchers' at one particular location (Alto Patache, 20°48'S) are consistent with altitudinal relationship: at high altitudes between 700-850 m, the water yield is maximum. Based on these results, the question is posed on whether this relationship was also present during the geological past. It has been shown that hyperaridity began prior to 10 Ma and once initiated it persisted, albeit with climate variability. The 87Sr/86Sr of dated paleosols in the study area allows us to test the use of this method as a paleoaltimeter after appropriate corrections are developed. For example, seawater 87Sr/86Sr changed with time, so that one of the end members of an idealized two-component mixture will requiere temporal corrections. Also, eustatic sea level changed, while climate variability would have affected the continental atmospheric inversion layer. The latter controls the vertical structure of the marine aerosols, so additional corrections may be needed. Preliminary results for paleosol samples are promising. After protocols for corrections are developed, this independent paleoaltimeter can be used to analize the relative importance of tectonics and climate in the geomorphologic history of the Atacama Desert.

Identification of 16SrIX-C phytoplasmas in Argyranthemum frutescens in Italy

Directory of Open Access Journals (Sweden)

Luca FERRETTI

2015-04-01

Full Text Available Phytoplasmas are cell wall-less microorganisms associated with plant diseases worldwide. Many important food, vegetable and fruits crops as well as ornamental plants can be severely affected by these pathogens, with significant economic impacts. Phytoplasma diseases of ornamentals have been described worldwide in a wide range of plant genera, and 11 different 16Sr groups have been identified. In Italy, many ornamental plant species belonging to several botanical families have been found to be infected by phytoplasmas, classified into the ribosomal groups 16SrI, 16SrII, 16SrV and 16SrXII. During a survey carried out in commercial gardens in Rome, some marguerite daisy (Argyranthemum frutescens plants showing symptoms of phytoplasma-like disease, were collected and submitted to molecular analyses. Cloning and sequencing of the portion of the 16S rRNA gene followed by BLAST analysis, real and virtual restriction fragment length polymorphism anlaysis with AluI and RsaI, allowed assignment of the detected phytoplasma to the 16SrIX-C group (Picris echioides yellows, PEY.

High-Precision In Situ 87Sr/86Sr Analyses through Microsampling on Solid Samples: Applications to Earth and Life Sciences

Directory of Open Access Journals (Sweden)

Sara Di Salvo

2018-01-01

Full Text Available An analytical protocol for high-precision, in situ microscale isotopic investigations is presented here, which combines the use of a high-performing mechanical microsampling device and high-precision TIMS measurements on micro-Sr samples, allowing for excellent results both in accuracy and precision. The present paper is a detailed methodological description of the whole analytical procedure from sampling to elemental purification and Sr-isotope measurements. The method offers the potential to attain isotope data at the microscale on a wide range of solid materials with the use of minimally invasive sampling. In addition, we present three significant case studies for geological and life sciences, as examples of the various applications of microscale 87Sr/86Sr isotope ratios, concerning (i the pre-eruptive mechanisms triggering recent eruptions at Nisyros volcano (Greece, (ii the dynamics involved with the initial magma ascent during Eyjafjallajökull volcano’s (Iceland 2010 eruption, which are usually related to the precursory signals of the eruption, and (iii the environmental context of a MIS 3 cave bear, Ursus spelaeus. The studied cases show the robustness of the methods, which can be also be applied in other areas, such as cultural heritage, archaeology, petrology, and forensic sciences.

A study of internal dosimetry of Am-241 and Sr-90 by dismantling of a nuclear installation; Eine Fallstudie zur internen Dosimetrie von Am-241 und Sr-90 bei Rueckbau einer kerntechnischen Anlage

Energy Technology Data Exchange (ETDEWEB)

Froning, M.; Hill, P. [Forschungszentrum Juelich GmbH (Germany). Geschaeftsbereich Sicherheit und Strahlenschutz

2016-07-01

During dismantling operation in former nuclear facility routine incorporation monitoring had been part of the safety measures. For an occupational radiation worker positive measurements results for {sup 241}Am, {sup 90}Sr and {sup 137}Cs were obtained after the end of the working period. Follow up monitoring had been performed assessing urine and faeces samples for {sup 241}Am and {sup 90}Sr as well as in-vivo measurements for {sup 137}Cs. Ingestion could be proven as incorporation path. The internal dose assessment according to GMBl 2007{sup [1]} finally yielded internal dose at 13 μSv.