Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

 

In this paper, the authors reported a forecasted analysis of the nuclear reactor market to meet

the global low carbon industrial heat demands. This provides a reference for further research. The paper is logically organized and well written. I am in favor of the publication of this paper, after a suitable revision to improve the points listed below.

 

1. It is necessary to explain the impact of the use and development of new energy on the results in the article, especially the "Rest of the Industries";
2. For heating greater than 750 ° C, in addition to direct heating with HTGR, electricity can also be directly generated. Compared with the material challenges of HTGR, the cost of electricity generation may be lower. It is necessary to explain the impact of using electricity to provide heat sources greater than 750 ° C on the results in the article, especially the number of LWRs;
3. In terms of the entire lifecycle of nuclear power plants, their carbon emissions are not zero, and it is necessary to explain the impact of carbon emissions throughout the lifecycle of nuclear power plants on the results presented in the article.

 

Author Response

The authors would like to thank the reviewer for taking time to review the article. We believe that the comments have now been address as shown below.

Reviewer comment: It is necessary to explain the impact of the use and development of new energy on the results in the article, especially the "Rest of the Industries";

Response: A line has been added to clarify the challenges with this data and how this makes new energy deployment challenging. The line reads “The steep rise in this new demand is hard to understand due to the lack of details provided within the dataset which makes this challenging to decarbonise.” I hope that I have interpreted this comment correctly.

Reviewer comment: For heating greater than 750 ° C, in addition to direct heating with HTGR, electricity can also be directly generated. Compared with the material challenges of HTGR, the cost of electricity generation may be lower. It is necessary to explain the impact of using electricity to provide heat sources greater than 750 ° C on the results in the article, especially the number of LWRs;

Response: I have touched on this point in the section on iron and steel but I have explicitly added a new line on the 3.3 demand summary stating “There could also be opportunities for electrification of industries through the use of a LWR to provide heat, even for industries with greater temperature requirements and further economic modelling could help to confirm this.”

Reviewer comment: In terms of the entire lifecycle of nuclear power plants, their carbon emissions are not zero, and it is necessary to explain the impact of carbon emissions throughout the lifecycle of nuclear power plants on the results presented in the article.

Response: We have not claimed that nuclear reactors are completely carbon neutral but low emissions. I have added in the demand section the following lines to address the reviewers comment. “This article focuses on replacing demands met by fossil fuels and has not considered a lifecycle assessment of the energy produced which would provide a more comprehensive analysis of carbon savings.”

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

1. The statement "Currently nuclear energy is almost exclusively used for electricity generation" in the introduction may not be entirely accurate. Currently, nuclear energy plays an important role in various areas such as the production of medical isotopes. The tone could be moderated appropriately to ensure the article's rigor.
2. The methodology section could provide a more detailed introduction to the formulas used in the model.
3. The model uses the World Bank population database to provide projected population for the required countries. If alternative population data sources are used, would it significantly impact the results? The feasibility of using other databases needs to be demonstrated, preferably with comparative results using different data sources for validation.
4. Multiple literature citations contain the error "Error! Reference source not found", please correct them.
5. Nuclear-enabled hydrogen production is one of the more important engineering applications of nuclear energy. The text states "For some of the industries with greater temperature requirements than 750 °C, nuclear enabled hydrogen could be a viable option, but this isn't considered here." Specific reasons for not considering nuclear-enabled hydrogen production should be provided.
6. Equations should be numbered following the formula, and the asterisk "*" should not be used as the multiplication sign.
7. Computer-generated numbered lists should not be used; the second line should be flush left. For example: P237-P243.
8. Are Figures 1-4 all straight lines? Why?
9. It is recommended to express the conclusions in 3-4 bullet points.
10. The reference format should be unified.

Author Response

Reviewer comment: The statement "Currently nuclear energy is almost exclusively used for electricity generation" in the introduction may not be entirely accurate. Currently, nuclear energy plays an important role in various areas such as the production of medical isotopes. The tone could be moderated appropriately to ensure the article's rigor.

Response: I do believe the statement used in the article is accurate from a power perspective as they are much larger but I do appreciate the authors comment and this is likely due to my perspective. I have added more detail into this line, to emphasise it’s the energy use. This now reads as follows: “Currently the main use of energy from nuclear systems almost exclusively used for electricity generation, but its primary energy output is heat, which could also be used to support other processes (4).”

Reviewer comment: The methodology section could provide a more detailed introduction to the formulas used in the model.

Response: A lot of the formulas in the model are quite self-explanatory, e.g GDPPC is based on historical data and extrapolation. The only real formula (which is often hard to find) is displayed in the text and explained.  We did not feel the requirement to add additional details but if the reviewer wishes to expand on where more detail could be added, we will revisit this comment.

Reviewer comment: The model uses the World Bank population database to provide projected population for the required countries. If alternative population data sources are used, would it significantly impact the results? The feasibility of using other databases needs to be demonstrated, preferably with comparative results using different data sources for validation.

Response:  I completely agree with the reviewers comment – one of the limitations when producing the model was that data is required for every country in the world. The databases chosen provided sufficient data to perform the analysis but there are no other databases available to do a cross-comparison. I have added the following text in the formulas section to identify this limitation: “The use of additional datasets for the world population and GDPPC could provide more rigor and a method of ap-plying uncertainty into the model based on the data use. However, very few databases with these details for every country required are available and this limits the model to the data chosen.”

Reviewer comment: Multiple literature citations contain the error "Error! Reference source not found", please correct them.

Response: I have just refreshed all the references and then built the article in a PDF. I cannot see a single error on the references. My apologies this has happened, I hope that the editor doesn’t have the same issue but I cannot amend this fault.

Reviewer comment: Nuclear-enabled hydrogen production is one of the more important engineering applications of nuclear energy. The text states "For some of the industries with greater temperature requirements than 750 °C, nuclear enabled hydrogen could be a viable option, but this isn't considered here." Specific reasons for not considering nuclear-enabled hydrogen production should be provided.

Response: I agree with the reviewer’s comment and I am an advocate for hydrogen production from nuclear energy. The article focuses on heat and I fear that if I tried to claim market demand for hydrogen via a number of nuclear reactors this could be challenged (as there is also a lot of uncertainty and low TRL). This is why I have left the temperatures greater than 750 C section in, as this can be met via hydrogen, but I have not tried to quantify nuclear reactor but the demand that needs to be replaced. I have added a bit more text in response to the reviews comment: “For some of the industries with greater temperature requirements than 750 °C, nuclear enabled hydrogen could be a viable option. Hydrogen production and demand from nuclear energy is not evaluated here to add conservatism to the outputs of this article.”

Reviewer comment: Equations should be numbered following the formula, and the asterisk "*" should not be used as the multiplication sign.

Response: This has been amended as per the reviewer’s comments.

Reviewer comment: Computer-generated numbered lists should not be used; the second line should be flush left. For example: P237-P243.

Response: We have rewritten the references used as per the requirements in the MDPI style guide.

Reviewer comment: Are Figures 1-4 all straight lines? Why?

Response: These figures are not straight lines – demand forecasting takes into account population and GDPPC changes over time. Some countries have a declining population and this sees some dips, others have population increases. Similarly with GDPPC.

Reviewer comment: It is recommended to express the conclusions in 3-4 bullet points.

Response: I thought about this comment and as the conclusion is only four short sentences, I did not believe that the bullet points made it more concise, the flow of the sector got worse. I have therefore left this section as it currently stands.

Reviewer comment: The reference format should be unified.

Response: We have rewritten the references used as per the requirements in the MDPI style guide.

Author Response File: Author Response.docx