NuScale International Test Programs
SIET Separate Effects and Prototype Steam Generator Testing
NuScale’s SMR uses compact, highly efficient helical coil steam generators (HCSGs) with many proprietary design features. NuScale contracted with the Società Informazioni Esperienze Termoidrauliche (SIET) in Piacenza, Italy to obtain test data to validate HCSG design under conditions that result from natural circulation flows in the NuScale reactor coolant system. Tests, completed in early 2014, focused on the secondary side performance and consisted of an electrically-headed, highly instrumented, full-length 3-tube bundle. The second test, completed in 2015, focused on overall primary and secondary side performance and consisted of a prototypic tube bank operated at prototypic primary and secondary flow conditions.
Thermal-Hydraulic and Mechanical Testing of Preliminary and Final Fuel Designs
NuScale’s SMR uses natural circulation driven flows in the reactor coolant system to provide reliable core heat removal during normal plant operation and for accident conditions.
To obtain critical heat flux (CHF) test data suitable to validate the fuel bundle design, NuScale completed a major test program for its preliminary fuel design at Stern Laboratories in Ontario, Canada. Testing was conducted over a wide range of natural circulation flow rates and pressures with both uniform and non-uniform power profiles. Results from the Stern testing is being used to characterize NuScale’s SMR performance margin and to inform design optimizations and testing of the final fuel design.
Testing of the final fuel design is underway at the AREVA KATHY multifunction thermal-hydraulic test loop in Karlstein, Germany. This facility tests both steady-state and transient thermal-hydraulic behavior of the fuel assemblies.
Thermal-hydraulic fuel testing requirements extend beyond the need for CHF characterization, and the AREVA Richland Test Facility has been employed to complete lift-off, pressure drop, and hydraulic characterization of the final fuel design. Additionally, mechanical testing of the new fuel design has been conducted at the Richland Test Facility to measure the physical capabilities of the design.
Control Rod Assembly and Drive Shaft Drop Alignment Test
Prototypes of the NuScale control rod assembly, guide tube, supports and fuel assembly have been fabricated and shipped to the AREVA GmbH test site in Erlangen, Germany.
Fabrication of prototypic drive shaft is in process. The tests will measure the CRA insertion rate under different operational conditions.
Flow Induced Vibration Tests
NuScale has enlisted AREVA, SIET, and Premier Technologies to fabricate and perform helical coil steam generator flow induced vibration (FIV) tests. The goal will be to determine natural frequencies and mode shapes of prototypic tubes and supports. Tests will also characterize dynamic pressure fluctuations, tube stresses/strains and tube support stresses/strains. Valuable steam generator assembly and manufacturing insights will be obtained.
Steam Generator Tube Inspection Feasibility Study
A feasibility study was completed by NuScale to evaluate the use of eddy current probes to inspect the NuScale helical coil steam generator tubes. Specifically, the ability of a conventional probe system to traverse the NuScale Helical Coil SG design was addressed. Helical coils with prototypic lengths, diameters, curvatures and inclination angles were traversed using a conventional eddy probe system, indicating acceptable insertion capability of a conventional eddy probe system.