Bounding severe water ingress analysis in modular high-temperature gas-cooled reactors

Conference · Mon Jan 01 00:00:00 EST 1990 · Transactions of the American Nuclear Society; (USA)

OSTI ID:6005188

Kroeger, P G ^[1]

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1. Brookhaven National Lab., Upton, NY (USA)

A major safety advantage of modular high-temperature gas-cooled reactors (MHTGRs) is the slow response to most postulated accident transients. Because of its high-quality ceramic fuel, significant fission product release resulting from fuel failure can only occur if the fuel is exposed for an extended time period to temperatures significantly above 1600{degree}C. The only conceivable mechanistic scenario for early and significant fuel failures would be a very severe and rapid water ingress into the core, which could result in a significant reactivity insertion and fuel heatup. During normal operation, {approximately}160 kg/s of helium are circulated, entering the core at {approximately}260{degree}C and exiting at {approximately}690{degree}C. Coolant transit time through the loop is {approximately}10 s. If a severe break in the steam generator were to occur, water would enter the primary loop, mix with helium, and enter the core as vapor. The severity of any such ingress transient would depend on how fast the vapor could enter the core, and in what concentration. This would be primarily a function of the break location and size. The approach taken here is to evaluate, as an upper bound, the temperature transient for the most severe, yet physically possible, water ingress scenario, namely, that the water vapor concentration in the core rises from 0 to 100% within a very short time, where the rise time is to be varied parametrically.

• OSTI ID: 6005188
• Report Number(s): CONF-901101-; CODEN: TANSA
• Journal Information: Transactions of the American Nuclear Society; (USA), Vol. 62; Conference: American Nuclear Society (ANS) winter meeting, Washington, DC (USA), 11-15 Nov 1990; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
HTGR TYPE REACTORS
PRIMARY COOLANT CIRCUITS
REACTOR SAFETY
STEAM GENERATORS
MOISTURE
RUPTURES
DOPPLER EFFECT
FISSION PRODUCT RELEASE
FUEL CHANNELS
FUEL ELEMENTS
HEATING
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MODULAR STRUCTURES
PARAMETRIC ANALYSIS
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REACTIVITY INSERTIONS
REACTOR ACCIDENTS
REACTOR CORES
REACTOR KINETICS
S CODES
T CODES
TIME DEPENDENCE
TRANSIENTS
ACCIDENTS
BOILERS
COMPUTER CODES
COOLING SYSTEMS
ELEMENTS
ENERGY SYSTEMS
FAILURES
FLUIDS
GAS COOLED REACTORS
GASES
GRAPHITE MODERATED REACTORS
KINETICS
NONMETALS
RARE GASES
REACTIVITY
REACTOR CHANNELS
REACTOR COMPONENTS
REACTOR COOLING SYSTEMS
REACTORS
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220900* - Nuclear Reactor Technology- Reactor Safety
210300 - Power Reactors
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