Identification of safe and stable zone of operation in supercritical water reactor

Numerical analysis of parallel-channel density wave instabilities in a supercritical water reactor

“…The TH model, used for the analysis of the PV SCWR based on a single channel [14,35], is extended at present to account for the radial or azimuthal non-uniformity in reactor power distribution among the different FAs by the incorporation of parallel channels in the TH model. To account for the effect of radial or azimuthal power variation inside the reactor core, a power asymmetry factor is introduced in such a way that the average reactor power remains the same.…”

“…In the present investigation carried out for the analysis of both the core-wide and regional DWOs for the PV SCWR, the simulations are generally performed with the parameters mentioned in Table 5 unless mentioned otherwise. The simulations are carried out with 120 axial nodes and time step size of 0.01 s on the basis of grid sensitivity tests performed in the earlier research work [14]. Identical number of nodes and time step size were used in [14] where the DWI for the same PV SCWR was analyzed on the basis of single channel, and grid independent results were obtained.…”

“…The simulations are carried out with 120 axial nodes and time step size of 0.01 s on the basis of grid sensitivity tests performed in the earlier research work [14]. Identical number of nodes and time step size were used in [14] where the DWI for the same PV SCWR was analyzed on the basis of single channel, and grid independent results were obtained. Since several such single channels of identical dimensions are used for the present parallel-channel DWI analysis, it is observed that the results obtained with the same number of nodes and time step size are adequate for the analysis of DWIs in the parallel-channel PV SCWR core as well.…”

“…Because of the several related research works on the supercritical fluids (SCFs) conducted in the recent past [1][2][3][4][5][6][7][8][9][10][11][12][13][14] in addition to the decades together related research experience [15][16][17][18][19][20] and based on those findings, it is reasonable to believe that the development of a SCWR is one of the viable options to implement the generation IV nuclear reactor in practice and make it operational in the near future, provided the remaining uncertainties associated with a new possible technology are addressed adequately. The TH stability and the related safety of the SCWR are one of the important identified areas which have received a considerable importance among the concerned scientific community.…”

“…The related research works, in spite of the varied nature of those, more or less agree that a SCWR, in its relevant operating conditions, might undergo DWOs, a dynamic instability, which gets originated purely due to the nonlinear interactions of the TH parameters and might get influenced with the neutronic parameters as well. The TH models, which have been used for the prediction of DWOs, can be based on linear perturbation and frequency-domain approaches [1-3, 5, 8, 21, 22], or based on nonlinear time-domain solution methodologies [5,[9][10][11][12][13][14]. Although the fact that the MSBs predicted from these two categories of models occasionally differed in quantitative agreements, the related studies with these models did predict the possibility of DWOs in an SCW system considering a single channel, subjected to the highest reactor power, as a representative of the complete reactor core.…”