Mathematical Modelling Forecast on the Idling Transient Characteristic of Reactor Coolant Pump

Round 1

Reviewer 1 Report

This paper describes a simplified model developed to describe pump coast-down behaviors as a function of time, fluid behavior and mechanical design.   Though more sophisticated models are already developed, this paper attempts to develop a simplified model that describes the phenomenology of interest.   However, it is unclear if this simplified model is of interest or if it sufficiently describes the behavior of pump idling at all conditions.   Further, the English language and style is poor, to the point where it is difficult to understand what is being communicated.   It is possible that this paper is worthy of inclusion in the journal, but first it must be carefully edited for English quality and style, and then the value of the simplified model must be highlighted, and made significantly more clear.

Author Response

Reply:The English academic writing style has been improved , and the value of simplifying the model has been highlighted.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript is potentially interesting, however some issues points to be clarified before considering it for publication, namely:

- Pag. 1, ine 25: <<[…] the potential threat of the safety […]>> should be <<[…] the potential threat for the safety […]>>

- Pag. 1 , line 36: the sentence <<[…] that conducted by scholars at domestic and foreign […]>> is not clear/correct

- Pag. 1, line 39: <<[…] it was also discovered that […]>> should be <<[…] it was also found that […]>>

- Pag. 4, line 115: <<shownin>> should be <<shown in>>

- Could you supply further details on the performed simulations (e.g. How many elements have your grids? Have you performed a sensitivity analysis on the grids dimensions? Have you validated the used input model? …)?

- Pag. 4, line 125: <<The turbulence model>> should be <<the turbulence model>> 

- Have you performed a sensitivity analysis on the different available turbulence models?

- Could you further comment on the improvements of your proposed methodology with respect to the others already available in literature?

Author Response

The manuscript is potentially interesting, however some issues points to be clarified before considering it for publication, namely:

 

- Pag. 1, ine 25: <<[…] the potential threat of the safety […]>> should be <<[…] the potential threat for the safety […]>>

 

Reply:“the potential threat of the safety”have been modified to “the potential threat for the safety”

 

- Pag. 1 , line 36: the sentence <<[…] that conducted by scholars at domestic and foreign […]>> is not clear/correct

 

Reply:“ Many studies can be referred to on the transient changes law after the power failure or shut-down of reactor coolant pump that conducted by scholars at domestic and foreign [1-4]”have been modified to “Many studies that conducted by scholars at domestic and foreign [1-4] can be referred to on the transient changes law after the power failure or shut-down of reactor coolant pump .”

 

- Pag. 1, line 39: <<[…] it was also discovered that […]>> should be <<[…] it was also found that […]>>

 

Reply:“it was also discovered that”have been modified to “it was also found that ”

 

 

- Pag. 4, line 115: <<shownin>> should be <<shown in>>

 

Reply:“shownin”have been modified to “shown in ”

 

 

- Could you supply further details on the performed simulations (e.g. How many elements have your grids? Have you performed a sensitivity analysis on the grids dimensions? Have you validated the used input model? …)?

 

Reply: Now, in the manuscript, information such as grid independence checking and grid number was added.  “Considering the computational resources and ensuring the better convergence of the computational model, hexahedral structure grid is adopted in the fluid domain and the boundary layer and interface region on the blade surface are locally encrypted. After grid independence check, it is found that when the grid number of the model was higher than 2.5 million, the head change was less than 0.5%. Taking the calculated resources and calculation accuracy into consideration, the total number of grid dividing units in the fluid domain is about 2.561 million, among which the number of grid units in the inlet section, impeller water body, guide vane water body and volute water body is 341 thousand, 528 thousand, 915 thousand and 771 thousand  respectively. Figure 2(e) shows the mesh cross section and independence test diagram of reactor coolant pump.” was added.

 

- Pag. 4, line 125: <<The turbulence model>> should be <<the turbulence model>> 

 

Reply:“The turbulence model”have been modified to “the turbulence model ”

 

- Have you performed a sensitivity analysis on the different available turbulence models?

 

Reply: I have published many papers on reactor coolant pump before, and also studied the turbulence model applicable to  reactor coolant pump calculations. It is found that if only for calculation of hydraulic performance of reactor coolant pump, the calculation results of Standard k-ε, RNG k-ε model, SST model, and k-Omega model model are similar.

 

- Could you further comment on the improvements of your proposed methodology with respect to the others already available in literature?

 

Reply: This paper is aimed at study the reactor coolant pump idling transient condition under sudden power failure. The parametric design of the reactor coolant pump is carried out, and the relationship between different parameters on the reactor coolant pump idling performance is analyzed, and the  complete mathematical model of the relationship between the geometry of the reactor coolant pump and the idling performance is established. The idling transient process is mathematically processed and the resulting mathematical model is experimentally verified. These are not covered in other papers.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

English challenges have been corrected and updates to topics that were previously unclear have been incorporated.