Water NSTF Design, Instrumentation, and Test Planning

Abstract

The following report serves as a formal introduction to the water-based Natural convection Shutdown heat removal Test Facility (NSTF) program at Argonne. Since 2005, this US Department of Energy (DOE) sponsored program has conducted large scale experimental testing to generate high-quality and traceable validation data for guiding design decisions of the Reactor Cavity Cooling System (RCCS) concept for advanced reactor designs.The most recent facility iteration, and focus of this report, is the operation of a 1 /2 scale model of a water-RCCS concept. Several features of the NSTF prototype align with the conceptual design that has been publicly released for the AREVA 625 MW t SC-HTGR. The design of the NSTF also retains all aspects common to a fundamental boiling water thermosiphon, and thus is well poised to provide necessary experimental data to advance basic understanding of natural circulation phenomena and contribute to computer code validation. Overall, the NSTF program operates to support the DOE vision of aiding US vendors in design choices of future reactor concepts, advancing the maturity of codes for licensing, and ultimately developing safe and reliable reactor technologies.In this report, the top-level program objectives, testing requirements, and unique considerations for the water cooled test assembly are discussed, and presented in sufficient depth to support defining the program's overall scope and purpose. A discussion of the proposed 6-year testing program is then introduced, which outlines the specific strategy and testing plan for facility operations. The proposed testing plan has been developed to meet the toplevel objective of conducting high-quality test operations that span across a broad range of single-and two-phase operating conditions. Details of characterization, baseline test cases, accident scenario, and parametric variations are provided, including discussions of later-stage test cases that examine the influence of geometric variations and off-normal configurations.The facility design follows, including as-built dimensions and specifications of the various mechanical and liquid systems, design choices for the test section, water storage tank, and network piping. Specifications of the instrumentation suite are then presented, along with specific information on performance windows, measurement uncertainties, and installation locations. Finally, descriptions of the control systems and heat removal networks are provided, which have been engineered to support precise quantification of energy balances and facilitate well-controlled test operations.

An Overview of Non-LWR Vessel Cooling Systems for Passive Decay Heat Removal (Technical Letter Final Report)

“…In 2010, Argonne initiated an experimental program to design, construct, and operate a large-scale test facility to examine the performance of the air-based RCCS concept for the GA-MHTGR. With the successful conclusion of air-testing in 2016, the NSTF program began a conversion of the test facility to water-based cooling [86]. This second iteration the NSTF at Argonne was based on a water-cooled RCCS and designed to align with major features of the concept design for Framatome's s 625 MWt SC-HTGR.…”

“…of primary dimensions and operating parameters of the water-based NSTF[86] Figure65: Installation of water cooling panel test section during construction of water NSTF[86] …”

Development of a Reference Model for Molten-Salt-Cooled Pebble-Bed Reactor Using SAM

“…The airbased NSTF testing program was successfully concluded in FY16. The current effort in NSTF testing program focus on water-based RCCS concept [13]. This section documents the modeling and computational analysis of RCCS in water-based NSTF with SAM's multidimensional flow module [2].…”

“…13 shows the steady-state water temperature and the tube wall inner surface temperature. Because the physical conditions are…”

Report on Year-2 of Water NSTF Matrix Testing

“…thermal and mass balance, both temperature and flow measurements utilize sensors that are minimally intrusive and exhibit very low uncertainty. Details of each sensor are provided in the following sections, with a high level summary provided in Table 1, a facility diagram of installed locations in Figure 3, and complete details in previous reports [4].…”