Experimental and numerical studies of seismic fluid‐structure interaction in a base‐supported cylindrical vessel

Self Cite

Numerical models capable of generating robust estimates of isolation-system and fluid-structure responses for multidirectional, high-intensity shaking will be required for analysis, design, and risk assessment of seismically isolated advanced reactors. None of the few studies to date on base-isolated, fluid-filled vessels have generated datasets suitable for formal validation of numerical models. Earthquake-simulator experiments on a fluid-filled, cylindrical vessel, base isolated using four single concave friction pendulum bearings (SFP isolators) were performed. The dataset was used to validate a numerical model for high intensity, multidirectional seismic inputs. Fluid and isolation-system responses obtained from analysis of the numerical model were in excellent agreement with experimental results. The numerical models and outcomes from the experiments are broadly applicable to base-isolated, fluid-filled vessels, regardless of industry sector.

Section: Test Specimen and Instrumentationmentioning

confidence: 99%

Section: Numerical Modelling In Ls‐dynamentioning

confidence: 99%

Section: Verification Validationmentioning

confidence: 99%

Section: Test Specimen and Instrumentationmentioning

confidence: 99%

Section: Numerical Modelling In Ls-dynamentioning

confidence: 99%

See 3 more Smart Citations

Validation of a numerical model of a seismically isolated, cylindrical, fluid‐filled vessel

Mir

Lal

Whittaker

et al. 2022

Self Cite

Development, verification, and validation of comprehensive acoustic fluid‐structure interaction capabilities in an open‐source computational platform

Dhulipala

Bolisetti

Munday

et al. 2022

Self Cite

The acoustic fluid-structure interaction (FSI) formulation is a practical numerical approach for the seismic analysis of fluid-filled tanks. However, there are no verification and validation studies reported in the literature that demonstrate the ability of an acoustic FSI numerical model to predict responses important to structural and mechanical design for intense translational and rotational earthquake inputs. Herein, an acoustic FSI formulation is implemented in the opensource Multiphysics Object-Oriented Simulation Environment (MOOSE), and is formally verified and validated using analytical solutions and code-to-code verification, and experimental data, respectively. The analytical solutions are for small amplitude, unidirectional seismic inputs. The code-to-code verification utilizes a previously verified and validated Arbitrary Lagrangian-Eulerian (ALE) numerical model in the commercial finite element code LS-DYNA. The validation studies utilize a comprehensive data set assembled from results of 3D earthquake-simulator tests of a fluid-filled vessel. The acoustic numerical model in MOOSE is verified and validated for hydrodynamic pressures and support reactions except for cases that involve significant convective response. For small amplitude inputs, numerically predicted wave heights match those of the analytical solutions. The numerical model is not verified and validated for wave height calculations under intense 3D seismic inputs. The run times for the acoustic FSI simulations in MOOSE are an order of magnitude, or more, shorter than for the corresponding ALE simulations in LS-DYNA. The utility of the MOOSE acoustic FSI implementation is demonstrated by seismic analysis of a building equipped with a fluid-filled, advanced nuclear reactor.

Mid‐height seismic isolation of equipment in nuclear power plants

Lal

Whittaker

Constantinou

2023

An innovative seismic isolation solution for designers of safety-class equipment in advanced nuclear power plants is introduced. The test specimen was a tall, slender, carbon steel vessel that could represent a reactor vessel, steam generator, or a heat exchanger in a nuclear power plant: 240 inches tall, outer diameter of 60 inches, and wall thickness of 1 inch. The vessel was supported by three radial mounts at its mid-height, near its center of gravity, on a steel frame. The vessel was subjected to three-component ground motions using a 6DOF earthquake simulator. The specimen was filled with water for testing to indirectly account for the fluid and internal equipment present inside a prototype vessel. Three configurations were tested: non-isolated, isolated using single Friction Pendulum (SFP) bearings, and isolated using triple Friction Pendulum (TFP) bearings. The test results demonstrate that mid-height seismic isolation is practical and enables a significant reduction in horizontal spectral accelerations. These outcomes are not specific to the spherical sliding bearings used in the experiments but are broadly applicable to mid-height, seismically isolated equipment. K E Y W O R D Searthquake-simulator experiments, equipment isolation, mid-height seismic isolation, nuclear power plants, safety-class equipment INTRODUCTIONSeismic isolation has been applied to more than 10,000 structures worldwide, including hospitals, data centers, buildings of cultural importance, bridges, emergency operations facilities, offshore oil and gas platforms, port facilities, container cranes, and electrical substations and power distribution systems. The benefits of seismically base isolating nuclear power plants (NPPs), in terms of reduced seismic demands and risk, are well established 1-8 but the technology is yet to be applied to an NPP (or a nuclear facility) in the United States. Parenthetically, seismic isolation is being considered as an integral design feature in some US advanced nuclear reactors, with the twin goals of steep reductions in capital cost and standardization of reactor designs. 9,10 Outside the U.S., two NPPs, in Cruas, France and Koeberg, South Africa, were base isolated in the early 1980s to enable the re-use of a certified plant design developed for a site of lower seismic hazard. Seismic isolation has also been implemented in the International Thermonuclear Experimental Reactor (ITER), the Jules Horowitz Reactor (JHR), the La Hague spent fuel storage pool, and the Georges Besse II uranium enrichment facility, all in France, with ITER and JHR under construction at the 998