Experimental Approach for the Failure Mode of Small Laminated Rubber Bearings for Seismic Isolation of Nuclear Components

Round 1

Reviewer 1 Report

it is a very interesting research, the investigation is well supported by the tests and analysis carried.

Author Response

Resolution for the reviewer’s comments

 

1) Manuscript ID: applsci-1494145                                               Date : 12/08/21

2) Title : Experimental Approach on the Failure Mode of Small Laminated Rubber Bearings for Nuclear Component Seismic Isolation

3) Authors : Sang-Jin Ma, Tae-Myung Shin *, Ju Seung Ryu, Jin Hyeong Lee, Gyeong-Hoi Koo

Review	No	Comments	Response
1	General	it is a very interesting research, the investigation is well supported by the tests and analysis carried	Thanks!
2	General	I only suggest that the type, formulation and curing conditions of the rubbers used be described.	Answer *
3	1/	Minor change of the title of the paper	OK (= Accepted)
	2/	Please include a List of Acronyms section.	OK
	3/	Literature review and recent references	OK
	4/	More specific in the main contribution of this paper in Introduction	OK
	5/	Include the reference of KS M ISO 22762	OK
	6/	Discussion about the dissipated energy in Figures 4, 5	OK
	7/	Proper citation of the ANSYS 2021 R2 in the references	OK
	8/	Improve the quality of Figures 10, 11, and 12	OK
	9/	Explain why the acceleration is lower always for low frequencies of the shaking table than dummy mass in Figures 13 and 14	Answer **
	10/	Change “Dumy Mass” to “Dummy Mass”	OK
	11/	Include number to every equation	OK
	12/	Discuss more about the possible implementation of the LRBs in new nuclear power plants	OK, Answer ***
	13/	Discuss more about the cost of these LRBs	Answer ****
	14/	In the References Section, please include DOI	OK(mostly except some)

 

Reviewer2* : Good comments, but the supplier wants not to open the technical details for rubber fabrication.

 

9** : As the purpose of seismic isolation is to reduce acceleration response of super structure, by shifting the natural frequency located in resonance peak zone with high seismic energy about 5Hz – 50Hz to a lower frequency zone. Therefore, the acceleration response of isolators are normally amplified near the design isolation frequency about 2.3 Hz in the case more than the acceleration of the shaking table.

 

12*** : In most conceptual designs of next generation nuclear power plants, they adopt a seismic isolation of nuclear islands including reactor building structures using numbers of large LRBs instead of individual equipment isolation. However, the small-sized LRB studied in the paper can be a good option among the seismic isolation devices for the seismic enhancement of the selective safety-related equipment of the operating nuclear plants.

13**** : The LRBs for equipment is enough reasonable in economic viewpoint in comparing some other options for seismic design. It is roughly expected to cost about 3,000 to 4000 US dollars for the isolation of a single equipment weighing less than 4 tons.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript details the response characteristics of rubber bearing systems for application in seismic isolation.
The work is well written and can be published without much modification.
I only suggest that the type, formulation and curing conditions of the rubbers used be described.

Author Response

Resolution for the reviewer’s comments

 

1) Manuscript ID: applsci-1494145                                               Date : 12/08/21

2) Title : Experimental Approach on the Failure Mode of Small Laminated Rubber Bearings for Nuclear Component Seismic Isolation

3) Authors : Sang-Jin Ma, Tae-Myung Shin *, Ju Seung Ryu, Jin Hyeong Lee, Gyeong-Hoi Koo

Review	No	Comments	Response
1	General	it is a very interesting research, the investigation is well supported by the tests and analysis carried	Thanks!
2	General	I only suggest that the type, formulation and curing conditions of the rubbers used be described.	Answer *
3	1/	Minor change of the title of the paper	OK (= Accepted)
	2/	Please include a List of Acronyms section.	OK
	3/	Literature review and recent references	OK
	4/	More specific in the main contribution of this paper in Introduction	OK
	5/	Include the reference of KS M ISO 22762	OK
	6/	Discussion about the dissipated energy in Figures 4, 5	OK
	7/	Proper citation of the ANSYS 2021 R2 in the references	OK
	8/	Improve the quality of Figures 10, 11, and 12	OK
	9/	Explain why the acceleration is lower always for low frequencies of the shaking table than dummy mass in Figures 13 and 14	Answer **
	10/	Change “Dumy Mass” to “Dummy Mass”	OK
	11/	Include number to every equation	OK
	12/	Discuss more about the possible implementation of the LRBs in new nuclear power plants	OK, Answer ***
	13/	Discuss more about the cost of these LRBs	Answer ****
	14/	In the References Section, please include DOI	OK(mostly except some)

 

Reviewer2* : Good comments, but the supplier wants not to open the technical details for rubber fabrication.

 

9** : As the purpose of seismic isolation is to reduce acceleration response of super structure, by shifting the natural frequency located in resonance peak zone with high seismic energy about 5Hz – 50Hz to a lower frequency zone. Therefore, the acceleration response of isolators are normally amplified near the design isolation frequency about 2.3 Hz in the case more than the acceleration of the shaking table.

 

12*** : In most conceptual designs of next generation nuclear power plants, they adopt a seismic isolation of nuclear islands including reactor building structures using numbers of large LRBs instead of individual equipment isolation. However, the small-sized LRB studied in the paper can be a good option among the seismic isolation devices for the seismic enhancement of the selective safety-related equipment of the operating nuclear plants.

13**** : The LRBs for equipment is enough reasonable in economic viewpoint in comparing some other options for seismic design. It is roughly expected to cost about 3,000 to 4000 US dollars for the isolation of a single equipment weighing less than 4 tons.

Author Response File: Author Response.docx

Reviewer 3 Report

This paper presents an experimental study about the failure mode of small laminated rubber bearing devices to be implemented in nuclear components of industrial plants. The contribution of the paper seems to be solid. The English is good as well (easy to follow). However, there are several revisions that must be performed before proceeding further. My recommendations are as follows:

1. The end of the title of the paper is very confusing. Please consider changing the title of the paper to “Experimental Approach on the Failure Mode of Small Laminated Rubber Bearing for Seismic Isolation of Nuclear Components”.
2. There are a lot of acronyms in the paper. In some part of the paper, please include a List of Acronyms section.
3. In the Introduction part of the paper, there are only 3 references reported. This is not reflecting the current state of the art of the problem that is intended to be solved by the Authors. Thus, please increase the literature review discussion in the Introduction section by including and discussing some other papers available in the literature. Please consider referring to recent papers that were published at most ten years ago.
4. By the end of the Introduction section is hard to understand the main contribution of this paper to the Applied Sciences journal. To address this issue, please try to be more specific in the main contribution of this paper.
5. In line 130, the Authors are reporting the use of the Korean Standard KS M ISO 22762, however, no reference is reported. Please include the reference of such a standard.
6. Figures 4 and 5 are very interesting, they are illustrating the hysteresis curve for OPT1 and OPT2, respectively. However, there are no discussion about the dissipated energy observed in Figures 4 and 5, respectively. Please include a small discussion about what can be seen in Figures 4 and 5 in terms of dissipated energy.
7. In line 192, the Authors are reporting the use if the Finite Element software ANSYS 2021 R2. However, no citation is included. To overcome this, please include the proper citation of the ANSYS 2021 R2 in the references section.
8. Please improve the quality of Figures 10, 11, and 12.
9. Please explain why in Figures 13 and 14 the acceleration (g) is lower always for short frequencies of the shaking table (non-isolated) in comparison with dummy mass (isolated).
10. In Figure 13 there is a typo for the red line label. Please change “Dumy Mass” to “Dummy Mass”.
11. In Figure 19, there is an equation reported. As far as I understand is the equation of motion. Anyhow, such an equation must be numbered. Please include number to every equation presented in the paper.
12. In the Conclusions Section, please discuss more about the possible implementation of the LRBs studied in this paper in the construction of new nuclear power plants. How feasible are they?
13. In addition, also in the Conclusions Section, please discuss more about the cost of these LRBs, what is the cost of them?
14. In the References Section, please include DOI for every paper reported in such a section.

Author Response

Resolution for the reviewer’s comments

 

1) Manuscript ID: applsci-1494145                                               Date : 12/08/21

2) Title : Experimental Approach on the Failure Mode of Small Laminated Rubber Bearings for Nuclear Component Seismic Isolation

3) Authors : Sang-Jin Ma, Tae-Myung Shin *, Ju Seung Ryu, Jin Hyeong Lee, Gyeong-Hoi Koo

Review	No	Comments	Response
1	General	it is a very interesting research, the investigation is well supported by the tests and analysis carried	Thanks!
2	General	I only suggest that the type, formulation and curing conditions of the rubbers used be described.	Answer *
3	1/	Minor change of the title of the paper	OK (= Accepted)
	2/	Please include a List of Acronyms section.	OK
	3/	Literature review and recent references	OK
	4/	More specific in the main contribution of this paper in Introduction	OK
	5/	Include the reference of KS M ISO 22762	OK
	6/	Discussion about the dissipated energy in Figures 4, 5	OK
	7/	Proper citation of the ANSYS 2021 R2 in the references	OK
	8/	Improve the quality of Figures 10, 11, and 12	OK
	9/	Explain why the acceleration is lower always for low frequencies of the shaking table than dummy mass in Figures 13 and 14	Answer **
	10/	Change “Dumy Mass” to “Dummy Mass”	OK
	11/	Include number to every equation	OK
	12/	Discuss more about the possible implementation of the LRBs in new nuclear power plants	OK, Answer ***
	13/	Discuss more about the cost of these LRBs	Answer ****
	14/	In the References Section, please include DOI	OK(mostly except some)

 

Reviewer2* : Good comments, but the supplier wants not to open the technical details for rubber fabrication.

 

9** : As the purpose of seismic isolation is to reduce acceleration response of super structure, by shifting the natural frequency located in resonance peak zone with high seismic energy about 5Hz – 50Hz to a lower frequency zone. Therefore, the acceleration response of isolators are normally amplified near the design isolation frequency about 2.3 Hz in the case more than the acceleration of the shaking table.

 

12*** : In most conceptual designs of next generation nuclear power plants, they adopt a seismic isolation of nuclear islands including reactor building structures using numbers of large LRBs instead of individual equipment isolation. However, the small-sized LRB studied in the paper can be a good option among the seismic isolation devices for the seismic enhancement of the selective safety-related equipment of the operating nuclear plants.

13**** : The LRBs for equipment is enough reasonable in economic viewpoint in comparing some other options for seismic design. It is roughly expected to cost about 3,000 to 4000 US dollars for the isolation of a single equipment weighing less than 4 tons.

Author Response File: Author Response.docx