PRISM Thermal-Hydraulic (Forced and Natural Convection) Complete In-Vessel-Model Performance Tests: Phase I and Phase II
In FY 1985, the U.S. DOE directed the Argonne National Laboratory (ANL) Flow and Mixing Processes Program to utilize its Mixing Components Test Facility (MCTF) to support the needs of the new Advanced Concepts Reactor Program for development of inherently safe, cost-competitive reactors. In cooperation with GE, a test program was developed to support PRISM, one of the advanced-concepts liquid metal reactor designs. The broadly stated objective of this program is to use the ANL/MCTF for transient and steady-state thermal-hydraulic tests, conducted in a scaled water model of the PRISM/RV and all major in-vessel components, to explore important high- and low-flow natural-convection operation scenarios for assessing factors that influence thermal-hydraulic performance, reactor coolability, and structural thermal distributions. This paper describes the ANL PRISM model and the results obtained from both Phase I and Phase II of the thermal-hydraulic test program. A transparent plastic (polycarbonate and cast acrylic), 1/5.24-scale model of the GE/PRISM advanced reactor was constructed at ANL. This model can be altered to reflect the evolving design. All major in-vessel components are represented in this model, which fits in a two-piece cylindrical containment vessel with large windows for laser flow visualization. The reactor core is simulated by a 60-kW electrical-resistance immersion heater with computer-interfaceable SCR power control. Computer-controlled forced flow is provided in two ways: for low-flow conditions, four in-vessel pumps (propellers driven by 1/4-hp dc motors with SCR controllers) are used; and for high-flow conditions, the MCTF water loop is used. Computer control of the immersion heater, in-vessel pumps, and the MCTF allows transient simulations. The two IHXs are designed to contain heat sinks, and the cold wall of the containment vessel simulates cooling by the RVACS. This model is the most complete thermal-hydraulic water model built to date for a U.S. DOE LMR program. A complete geometric model was built because the thermal-hydraulic performance of one subregion of the prototype under a variety of conditions will depend upon the conditions that prevail elsewhere in the reactor. Therefore, any similarity analysis of the model design should consider the whole RV. A one-dimensional similarity analysis, applicable to such a complete system, has been followed in developing the PRISM model. Phase I tests facilitated the shakedown process and the development of many complex control features and subsystems which have been incorporated in the PRISM model. The Phase I tests also highlighted specific thermal-hydraulic phenomena of potential interest to designers. The tests were conducted in the following general categories: isothermal flow distribution, hot plenum free-surface behavior, constant-flow thermal transients, natural-convection flows, and mixed forced-natural-convection flows. Phase II tests consisted of simulations of five prototypic transients which were chosen by GE because their severity and frequency of occurrence could pose potential design concerns such as stress problems caused by rapid temperature changes and inadequate heat rejection due to inadequate flow. A stratified hot/cold interface formation in the cold plenum, backflow in a shut down pump, and unanticipated natural-convection currents in the overflow gap are some of the phenomena that were discovered during these tests. These phenomena will be highlighted because of their possible importance to the designer.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 714167
- Report Number(s):
- ANL-PRISM-49; 157955
- Resource Relation:
- Other Information: PBD: Feb 1988
- Country of Publication:
- United States
- Language:
- English
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