This is a good basis for a project task like DECOVALEX-2027 SAFENET. It allows the general public to follow and even participate in this study. Therefore this is a very good example of transparency for the public. However, as a scientific paper, it should be revised  taking into account the following points:

1. The introduction should describe work on the general progress of the granite study, in particular on the issue of deep disposal. It should answer the following questions:
   1. Why is granite suitable for high-level waste disposal?
   2. What are the main problems to be solved in this context?
   3. What are the main outcomes of the past phases of DECOVLAEX before D2023?
2. The experimental data are presented in a very heterogeneous manner. The experimental data in the section 2.2.1 are described in detail, but 2.2.2 and 2.2.3 are very limited without results.
3. Results from the previous phase D2023 should be summarized in one section.
4. The intention to compare such complex tests as benchmarking is good, but a big challenge. Would it be possible to summarized some numerical methods used in the previous phase?

The paper describes the planned activities in the context of SAFENET-2, a task of DECOVALEX-2027 project. The overall structure and level of detail of the paper is coherent with the initial stage of the activities. Yet, in some sections some additional clarifications are necessary to understand whether the described activities belong to SAFENET or SAFENET-2, and whether they have been concluded or not (detailed comments below). 

Once these aspects are clarified, I suggest the authors to reconsider the title of paper, and whether if should be explicitly refer to SAFENET-2 (or both, SAFENET part 1 and 2).

1.    In the abstract and conclusions, it is said that the paper discuss safenet-2 plan, yet there is no mention of safenet-2 in the introduction. The provided overview on Decovalex and Safenet is useful, but it is not clear where the first part of safenet finishes, and the second part (addressed here) begins. As an example, in line 50 “SAFENET will also elaborate the potential of Artificial Intelligence (AI) concepts for…” is this safenet 2 or some remaining activities in safenet?  

2.    Section 2.1 Concept: 

a.    References for the GREAT cell and the thermoslip-flow cell, line 60, are necessary

b.    The approaches mentioned in lines 60-61 needs clarifications. In the figure (and in the conclusions), two approaches are considered: HM+T and TM+H, meaning that temperature and hydraulic are added on top of pre-existing approaches. In the text a “HM” and “TM-H” processes are mentioned. Please make the notation consistent and consider rephrasing and adding few details on how thermal and hydraulic effects are going to be included. 

c.    In line 64 “the second area of focus” is mentioned. Although before there was no mention of the number of areas of focus. Probably would be worth to either mention early on that there are two focuses, or rephrase here. 

3.    In section 2.2.1 GREAT cell large lab scale data

a.    in this section, it is not clear whether all experiments planned for safenet 2 are already concluded, or the results mentioned here are just preliminary and other tests are planned. 

b.    In line 90, the “SAFENET-2 HM Task 2” is mentioned, yet it is not clear what is the task 2, as this doesn’t seem to be mentioned before.

c.    Figure 4 (and 6, 7): the unit of measurements represented is not clear. Are those μstrain? Doesn’t it start from 0? 

d.    Figure 6 and 7: text in the figures is quite small and difficult to read. 

e.    Line 138: “and” is repeated twice

f.    Line 148: it is not clear what the authors meant by “mean modelled” normal stress. Same for the “modelled” maximum shear stress in line 149.

g.    Line 148: after normal stress, a full stop is missing. 

4.    Section 2.2.3 Stimtec in-situ experiments

a.    is this in situ experiments concluded? If so, it would be preferable to clarified that only the results would be exploited in the safenet-2, or else additional experimental activities should be detailed. In the planning at the end of paper, it seems that additional activities are planned for early next year. 

b.    Line 175, the references should be without parenthesis

5.    Section 2.3 Modelling approach

a.    Line 179: Here the authors are probably referring to safenet-2. Please double check.

b.    Line 187: step 0 does not seem to have been described before.

c.    Line 191: should be methods and codes

6.    Section 2.3.3 Step 3: Thermoslip-flow test case simulation

a.    The description at line 250 includes “keywords” of the test results, but it is not clear why the authors would mention keywords here. 

b.    Line 258-260: the authors refer to future workshops, which is unusual to me.  I’d leave the editor to judge whether this is acceptable for the current publication. 

c.    Line 262: models “will be examined”

d.    Line 267: full stop should be on the same line. 

7.    Section 3 Conclusions

a.    Line 286: the cross reference is to table 2 (instead of figure 3)