In Situ Neutron Radiography Investigations of Hydrogen Related Processes in Zirconium Alloys

Round 1

Reviewer 1 Report

Dear colleagues! I have read your article with significant interest. The method you used seems to be powerful, and provide extremely valid information about hydrogen uptake and evolution in structural materials. Certainly, I may recommend the article for publication despite of remarks listed below.

1. Page 1. Title: "In situ Neutron Radiography investigations of hydrogen related processes in Zirconium Alloys". Please, make either all first letters to be uppercase, or all (except first) - lowercase.
2. Page 1. 6-th line from the bottom: "outer presser is higher". Better is "outer pressure is higher"
3. Page 2. Figure 2.: It is necessary to show the scale of correspondence between the concentration of hydrogen and grayness. Otherwise, it is not clear where the concentration is higher.
4. Page 2. 5-th line from the bottom: "physio-chemical processes.". Misprint. Change to "physico-chemical processes."
5. Page 3. 5-th line from the top: "well defined and changeable gas atmosphere non-reactive furnace structures and sample holders ...". Not clear sentence. I would propose change to "well defined and changeable gas atmosphere, non-reactive furnace structures and sample holders ..." or "well defined and changeable gas atmosphere non-reactive with furnace structures and sample holders ...".
6. Page 4. 10-th line from the bottom: "... various nitrogen containing atmospheres". Insert point at the end of sentence.
7. Page 4. 1-st line from the bottom: "This cylinders were oxidized ..." In what atmosphere?
8. Page 5. 10-th line from the bottom: "These curves were fitted by the solution of Ficks law ...". It would be a nice idea to compare the experimental and theoretical curves in order to make a conclusion about the model's applicability. 
9. Page 6. 7-th line from the top: "... correlation given Someno [16] but at 900 and 1000°C by the one published by Gelezunas [17]." Insert comma before "but", change "by" to "with": "... correlation given Someno [16], but at 900 and 1000°C with the one published by Gelezunas [17]."
10. Page 7. 7-th line from the bottom: Please, add notations for the used values in equation (4).
11. Page 8.  3-rd line from the top. 3.2.3. Results and Discussion. Have the authors an idea what is the physical reasons of nonmonotonic character of hydrogen uptake with increasing exposition time (see especially dependence for 1273K in fig.9)? I believe it would be interesting to discuss this unexpected behavior in the article.
12. Page 8. 11-th line from the top: "... the oxide structure is transfererred to the monoclinic one.". Misprint. Change to "... the oxide structure is transferred to the monoclinic one."
13. Page 9. 16-th line from the top: "This oxygen and steam starvations can be globally at the whole sample or locally for instance at tips of cracks through the oxide scale." Not clear sentence. Please, modify. 
14. Page 9. 19-th line from the top: "The supprising outcome, that the reaction rate is the higher the lower the gas flow was expermentally confirmed." Two misprints. Change to "The surprising outcome, that the reaction rate is the higher the lower the gas flow was experimentally confirmed."
15. Page 9. 17-th line from the bottom: "partial pressures but". Insert comma before "but": "partial pressures, but".
16. Page 10. 17-th line from the bottom: "at1000°C". Insert missed space: "at 1000°C".
17. Page 10. 10-th line from the bottom: "former lower edge of the sample appear bright". Change to "former lower edge of the sample appears bright".
18. Page 11. 2-th line from the top: "flow rates of 2 g/h H2O". Make "2" as subscript: "flow rates of 2 g/h H₂O".
19. Page 12. 13-th line from the top: "... B. Schillinger All authors ...". Insert point: "... B. Schillinger. All authors ...".
20. Page 12. References. Please, make the references in uniform style. Insert titles if absent. Do not use all capitals in title and author names.

Author Response

see attached file

Author Response File: Author Response.pdf

Reviewer 2 Report

In this study, in situ Neutron Radiography investigations of hydrogen related processes in Zirconium Alloys has been investigated. Using conventional neutron radiography for investigation of hydrogen in zirconium alloys is not new and several groups in worldwide applied neutron imaging for such investigations during the last years, but the novelty of present study is using in-situ neutron radiography technique which can be very helpful to understand the dynamic of physio-chemical processes.

The paper’s subject is very practical and interesting. The research procedure has been logically carried out and includes adequate experimental works. Therefore, I highly recommend this paper for publication in this journal but before that, I have some few comments on the text:

 

Comments:

• In page 4, there two figures with a same number “Figure 4. The INRRO furnace….” and “Figure 4. Sample holder constructed…”. Please correct the figure numbers in all of the manuscript.

2)As I see in Fig.3 in page 3, there is water (H2O) around the sample holder (in fact between path of neutron source and detector). Since water can intensively scatter neutrons, could you please explain how did you reduce the scattering effects in your experiments?

3) What is the type of used detector? Is it a Lithium-based scintillator?

4) Does have your neutron imaging facility the capability of in-situ imaging of irradiated fuels rods? Or just can be used for fresh fuel?

5)Please point out somewhere in the text that how much is the thermal neutron flux of neutron imaging facility.

 

Author Response

see attached file

Author Response File: Author Response.pdf