Safety aspects of forced flow cooldown transients in Modular High Temperature Gas-Cooled Reactors

Technical Report · Sat May 01 00:00:00 EDT 1993

OSTI ID:10157018

Kroger, P G ^[1]

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1. Brookhaven National Lab., Upton, NY (United States)

During some of the design basis accidents in Modular High Temperature Gas Cooled Reactors (MHTGRs), the main Heat Transport System (HTS) and the Shutdown Cooling System n removed by the passive Reactor (SCS) are assumed to have failed. Decay heat is the Cavity Cooling System (RCCS) only. If either forced flow cooling system becomes available during such a transient, its restart could significantly reduce the down-time. This report used the THATCH code to examine whether such restart, during a period of elevated core temperatures, can be accomplished within safe limits for fuel and metal component temperatures. If the reactor is scrammed, either system can apparently be restarted at any time, without exceeding any safe limits. However, under unscrammed conditions a restart of forced cooling can lead to recriticality, with fuel and metal temperatures significantly exceeding the safety limits.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (United States). Div. of Systems Research; Brookhaven National Lab., Upton, NY (United States)
• Sponsoring Organization: Nuclear Regulatory Commission, Washington, DC (United States)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 10157018
• Report Number(s): NUREG/CR-5983; BNL-NUREG-52355; ON: TI93013475
• Resource Relation: Other Information: PBD: May 1993
• 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
AFTER-HEAT REMOVAL
REACTOR ACCIDENTS
HEAT TRANSFER
HYDRAULICS
REACTOR COOLING SYSTEMS
REACTOR SAFETY
T CODES
TRANSIENTS
CRITICALITY
SCRAM
DESIGN BASIS ACCIDENTS
FAILURES
220900
210300
POWER REACTORS
NONBREEDING
GRAPHITE MODERATED