Design inputs document: Boiling behavior during flow instability

Technical Report · Tue Jan 01 04:00:00 EST 1991

DOI:https://doi.org/10.2172/5630982· OSTI ID:5630982

Coutts, D A

The coolant flow in a nuclear reactor core under normal operating conditions is kept as a subcooled liquid. This coolant is evenly distributed throughout the multiple flow channels with a uniform pressure profile across each coolant flow channel. If the coolant flow is reduced, the flow through individual channels will also decrease. A decrease in coolant flow will result in higher coolant temperatures if the heat flux is not reduced. When flow is significantly decreased, localized boiling may occur. This localized boiling can restrict coolant flow and the ability to transfer heat out of the reactor system. The maximum operating power for the reactor may be limited by how the coolant system reacts to a flow instability. One of the methods to assure safe operation during a reducing flow instability, is to operate at a power level below that necessary to initiate a flow excursion. Several correlations have been used to predict the conditions which precede a flow excursion. These correlations rely on the steady state behavior of the coolant and are based on steady state testing. This task will evaluate if there are any deviations between the actual transient flow excursion behavior and the flow excursion behavior based on steady state correlations (ONB, OSV, and CHF). Correlations will be developed which will allow a comparison between the time to excursive behavior predicted using steady state techniques and the actual time to excursive behavior.

• Research Organization: Westinghouse Savannah River Co., Aiken, SC (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC09-89SR18035
• OSTI ID: 5630982
• Report Number(s): WSRC-MS-91-515; ON: DE92009655
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220200* -- Nuclear Reactor Technology-- Components & Accessories
220900 -- Nuclear Reactor Technology-- Reactor Safety
ACCIDENTS
BENCHMARKS
BOILING
COOLING SYSTEMS
ENERGY TRANSFER
EXCURSIONS
FLUID FLOW
FLUID MECHANICS
HEAT TRANSFER
HYDRAULICS
MECHANICS
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
NUCLEATE BOILING
PHASE TRANSFORMATIONS
POWER PLANTS
PRESSURE DROP
REACTOR ACCIDENTS
REACTOR CHANNELS
REACTOR COMPONENTS
REACTOR COOLING SYSTEMS
STEADY-STATE CONDITIONS
SUBCOOLED BOILING
THERMAL POWER PLANTS
UNSTEADY FLOW