Effects of coolant volatility on simulated HCDA bubble expansions. Technical report No. 10

Technical Report · Mon Sep 01 00:00:00 EDT 1980

DOI:https://doi.org/10.2172/7014106· OSTI ID:7014106

Tobin, R. J.

The effects of coolant volatility on the expansion dynamics and cover loading of hypothetical core disruptive accidents (HCDA) were studied by performing experiments with a transparent 1/30-scale model of a typical demonstration size loop-type liquid metal fast breeder reactor (LMFBR). Freon 113 and Freon 11 were used as coolant simulants of increasing volatility. High-pressure nitrogen gas (1450 psia) or flashing water (1160 psia) were used to simulate the qualitative features of sodium vapor or molten fuel expansions. To validate the use of constant mass and constant geometry experiments as a means of evaluating the effects of coolant volatility, a set of baseline experiments was performed in these configurations with the room temperature nitrogen bubble source. In all the experiments, the expanding HCDA bubbles, the motion of the coolant simulant, and the vessel loads were monitored by pressure transducers, a thermocouple in the bubble, and high-speed photography. Results of the constant mass experiments with the flashing water source show that higher volatility results in higher pressure driving the coolant slug and therefore higher impact loads. The Freon experiments had about 50% higher pressure in the upper core and bubble, a 30% larger slug impact impulse, and 25% greater expansion work done on the coolant slug. The higher pressure in the Freon experiments is believed due to vaporization of some of the Freon that mixes with the hot flashing water in the upper core very early in the expansion. Entrainment of coolant within the bubble and the bubble shape were comparable in the Freon and water experiments. Entrainment at slug impact varied between 20 and 40% of the bubble volume. The presence of internal vessel structures attenuated the slug impact impulse by about 50%, whether the coolant was Freon 113 or water. 79 figures, 23 tables.

• Research Organization: SRI International, Menlo Park, CA (United States)
• DOE Contract Number: AT03-76SF70097
• OSTI ID: 7014106
• Report Number(s): DOE/SF/70097-T3; TRN: 81-001830
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
LMFBR TYPE REACTORS
REACTOR CORE DISRUPTION
SIMULATION
REACTOR SAFETY EXPERIMENTS
FLASHING
FREONS
MOCKUP
NITROGEN
WATER
ACCIDENTS
BREEDER REACTORS
ELEMENTS
EPITHERMAL REACTORS
EVAPORATION
FAST REACTORS
FBR TYPE REACTORS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN COMPOUNDS
LIQUID METAL COOLED REACTORS
NONMETALS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
REACTOR ACCIDENTS
REACTORS
STRUCTURAL MODELS
220900* - Nuclear Reactor Technology- Reactor Safety
210500 - Power Reactors
Breeding