Document Type : Research paper
Authors
School of Mechanical Eng., Shiraz University, P.O.Box: 71936-16548, Shiraz, Iran.
Abstract
Due to its compact design, higher heat transfer efficiency, and ability to produce superheated steam , helical coil steam generators (HCSG) have become a popular option for use in small modular reactors. This research focuses on developing a multi-node moving boundary model for the transient calculation of these steam generators. The secondary side of an HCSG consists of subcooled, two-phase, and superheated regions. The developed model can accurately track the boundaries of these phases and allocate their proportional heat transfer coefficients accordingly. Additionally, each region is divided into multiple nodes for more increased accuracy. This approach eliminates the need for fine nodes and phase detection in each node during each time step, significantly reducing the computational cost of calculating of steam generator behavior. Python programming language was used for computationsin this study, which greatly improved the speed and efficiency of the calculations. Furthermore, a RELAP5 model for HCSG was developed in this research . The results obtained from the developed code were compared against with RELAP5 calculated parameters. Multiple scenarios involving changes feedwater in properties and primary flow to the steam generator were modeled. The simulated scenarios demonstrate that both codes show similar trends for variations in the parameters. The methodology presented in this study can be applied to model HCSG dynamics in future studies.
Keywords
- Small modular reactors
- Helical coil steam generator
- Multi-node moving boundary model
- Steam generator dynamical simulation
Main Subjects
- Secker, P. and J. Gilbert, Status of CHAP: composite HTGR analysis program. 1975, Los Alamos Scientific Lab.
- Kerlin, T., HTGR steam generator modeling. 1976, Oak Ridge National Lab.
- Industries, M.H., DESIGN CONTROL DOCUMENT FOR THE US-APWR. 2013: Nuclear Regulatory Commission.
- NuScale power LLC, NuScale Status in the Regulatory Process. 2017: http://www.nuscalepower.com/our-technology/nrc-interaction/.
- Atomenergoproekt, Final safety analysis report of BNPP’s VVER-1000 reactor. 2015: Moscow.
- Tzanos, C.P., A semianalytic method for the solution of the steady-state steam generator Nuclear Technology, 1988. 80(3): p. 380-391.
- Wu, Y., et al., A movable boundary model for helical coiled once-through steam generator using preconditioned JFNK method. International Journal of Advanced Nuclear Reactor Design and Technology, 2022. 4(1): p. 1-8.
- Berry, G., Model of a once-through steam generator with moving boundaries and a variable number of nodes. 1983, Argonne National Lab., IL (USA).
- Jensen, J.M. and H. Tummescheit. Moving boundary models for dynamic simulations of two-phase flows. In Proc. of the 2nd int. Modelica conference. 2002. Oberpfaffhenhofen Germary.
- Fakhraei, A., et al., Safety analysis of an advanced passively-cooled small modular reactor during station blackout scenarios and normal operation with RELAP5/SCDAP. Annals of Nuclear Energy, 2020. 143: p. 107470.
- Fakhraei, A., et al., Coolant flow rate instability during extended station blackout accident in NuScale SMR: Two approaches for improving flow stability. Progress in Nuclear Energy, 2021. 131: p. 103602.
- Fakhraei, A., et al., DYSN: Dynamics simulator for the NuScale SMR-A mathematical framework for transient analysis. Progress in Nuclear Energy, 2024. 170: p. 105128.
- Fakhraei, A., F. Faghihi, and M. Mohammadi, A Multi-Node Moving Boundary Model for Transient Dynamics of Nuscale Smr Steam Generator and Designing a Controller Using Fuzzy Logic and Pid. Available at SSRN
- NuScale Power LLC, NuScale Standard Plant Design Certification Application. 2020: U.S. Nuclear Regulatory Commission (NRC).
- Arda, S.E. and K.E. Holbert, Nonlinear dynamic modeling and simulation of a passively cooled small modular reactor. Progress in Nuclear Energy, 2016. 91: p. 116-131.
)