Evaluation of a Long-Term Thermal Load on the Sealing Characteristics of Potential Sediments for a Deep Radioactive Waste Disposal
Round 1
Reviewer 1 Report
The aim of this article is to evaluate the long-term impact of a heating experiment on the sealing characteristics (geochemical and mineralogical) of potential sediments for a deep radioactive waste disposal.
The structure of the article is quite satisfying, as the major sections (Introduction, Description of the experiments, the sampling and the analytical methods, Results, Discussion and Conclusions) are included. A detailed analysis has been performed in all sections, while the Figures, Diagrams and Tables sufficiently accompany the manuscript. However, the following corrections should be applied, which will lead the paper improvement:
· Lines 11-34: The Abstract should be brief and concise. It includes many details, which should be removed. Please, modify it and briefly describe the purpose, the major findings and the conclusions of your research.
· Lines 39-54: Although this is the initial part of the “Introduction” section, which generally describes the research background, no bibliographic references are provided. Please, cite the relative papers, in order to justify the theoretical background.
· Lines 75-78: The aim of this study should be placed at the end of the “Introduction” section, as a paragraph is interjected, describing details, which attract the attention from the major objective. Please, modify it.
· Figure 1a: Please, provide the geological formations legend. For examples, the geological map includes the formation, named “Shaly facies”. What is the composition of this formation? Please, describe the geological formations in detail.
· Figures 1b and 1c: Please, include the letters “a” and “b” in the corresponding figures.
· The resolution of all Figures and Diagrams should be increased, as blur parts are observed.
· The “Conclusions” section should be rewritten. In the current form, it seems more like an Abstract, rather than conclusions, while a lot of things are repeated. The concluding remarks should be solid and comprehensive. Maybe, you could apply numbering. Please, modify it.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The reviewer would like to thank the author on a very good job. however, several issues need to be addressed before publication.
1. The manuscript is too long for the evaluation of 2 site study.
2. To use shorter sentence to convey the points
3. To combine the result and discussion session to make sense of the data presented.
Other specific comment can be found in the reviewed document.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The heating experiments on clays were carried out to study of impact of heat on clay and rock. The results indicate that few changes happened, except for the variations in concentration of alkali elements and REE. The K-Ar data suggested degas of Ar happed obviously. However, the authors presented no visible alteration of host-rock with short time heating. If the author could propose comparison of typical XRD, SEM and Raman spectrum before and after heating, the conclusion will be more irrefutable. It makes no sense to present data twice with Figs. and Tables.
Beside that there are some mistakes which need to be corrected.
The table 1 should be corrected and unit of mg/g should be double checked.
Why the total ratio is not 100% in table 1?
The abbreviation of LOI should be introduced.
In Figs.4 and 5, the symbols with different colors such as cyan diamond are shown without any explanation.
Symbol of B is missing in Fig.6.
Table 6 the comma (,) should be replaced by point(.).
There is not any explanation on table 8.
The time values such as 830, 2529 and 1799 days, should be checked.
The reader will appreciate the detailed explanation of rock life.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
The manuscript provides interesting mineralogical, geochemical and K-Ar isotopic data on fine-grained sediments of the Opalinus Clay at Mont Terri (Switzerland) and the Boom Clay at Mol (Belgium) to test the impact of temperature rise of 100°C theoretically produced by nuclear wastes in deep repositories. Main results generated by heating experiments on both sediments indicated that: (1) no major mineralogical, geochemical and isotopic differences have found between unheated and heated samples and (2) degassing and dewatering of the minerals did not produce any visible alteration of the host-rock safety characteristics. In the end, authors propose that the differential behavior of radiogenic and atmospheric argon might become an interesting test for the evaluating sealing potentials of deep repositories.
I found the manuscript well organized and written, data are good and interpretation of results are convincing. The manuscript requires minor revision before being accepted for publication in Sustainability journal. I have uploaded a pdf file where minor comments and corrections are highlighted..
The method section (2.3) should contain further analytical details for X-ray diffraction analysis. What was the scanning interval of whole rock samples and oriented specimens? Were the samples run in continuum or by steps? What was the voltage and current intensity of the X-ray tube in your runs? Furthermore, some information are required on how the authors performed clay mineral quantification of the <2µm grain size fraction.
Geochemical changes (e.g. major oxides, REE) are interpreted invoking lithology or mineralogical variations among samples but the latter information are missing in the text and in the result section. In addition, there is a lack of documentation (e.g. figure showing X-ray patterns) of mineral phases occurring in the bulk and in the <2µm grain size fractions.
Authors should briefly describe the lithology variations in the Opalinus Clay and provide a selection of X-ray diffraction patterns of whole rock samples and <2 µm grain size fraction of Opalinus and Boom Clays for unheated and heated samples to strenghthen their geochemical interpretations. Futhermore a brief description of mineral variation approaching the heater, crystallization of new soluble minerals (e.g. carbonates, chlorides) and discrete mineral reorganization is highly required.
Some figures and tables need to be restyled. See my comments in the annotated pdf. File
Table 6 should contain the mineral content after 2529 days as well.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
