Risk and safety analysis in support of the operation at the High Flux Isotope Reactor at Oak Ridge
- Oak Ridge National Lab., TN (USA)
The High Flux Isotope Reactor (HFIR) is a high performance isotope production and research reactor which has been in operation at Oak Ridge National Laboratory (ORNL) since 1965. In late 1986 the reactor was shut down as a result of discovery of unexpected neutron embrittlement of the reactor vessel. In January of 1988 a Level 1 Probabilistic Risk Assessment (PRA) (excluding external events) was published as part of the response to the many reviews that followed the shutdown and for use by ORNL to prioritize action items intended to upgrade the safety of the reactor. A conservative estimate of the core damage frequency initiated by internal events for HFIR was 3.11 {times} 10{sup {minus}4}. It was dominated by flow blockages and loss of all AC power. In June 1989 a draft external events initiated PRA was published. The dominant contributions from external events came from seismic, wind, and fires. The overall external event contribution to core damage frequency is about 50 percent of the internal event initiated contribution and is dominated by seismic events. Several design and safety analysis studies were undertaken to support the restart of the HFIR. The first study involved a fracture mechanics analysis and redesign of the reactor operating conditions and safety system setting to provide a basis for future operation. Another study involved performing a risk analysis by combining the Level 1 PRA results with offsite consequence analyses under conservative assumptions about the fission product removal within the plant. Additional studies were performed to establish a long-term decay heat removal design basis. Finally, updated and upgraded loss-of-cooling accident studies were performed and are still underway. 5 refs., 11 figs., 6 tabs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- DOE/ER
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5579697
- Report Number(s):
- CONF-891027-4; ON: DE90001345
- Country of Publication:
- United States
- Language:
- English
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ACCIDENTS
ACTINIDE COMPOUNDS
BRITTLENESS
CONTAINERS
DESIGN
EMBRITTLEMENT
ENERGY TRANSFER
ENRICHED URANIUM REACTORS
FIRES
FLUID MECHANICS
HEAT TRANSFER
HFIR REACTOR
HYDRAULICS
IRRADIATION REACTORS
ISOTOPE PRODUCTION
ISOTOPE PRODUCTION REACTORS
LOSS OF COOLANT
MECHANICAL PROPERTIES
MECHANICS
POWER DENSITY
REACTOR ACCIDENTS
REACTOR SAFETY
REACTOR SHUTDOWN
REACTOR VESSELS
REACTORS
RESEARCH AND TEST REACTORS
RESEARCH REACTORS
RISK ASSESSMENT
SAFETY
SEISMIC EFFECTS
SHUTDOWN
TANK TYPE REACTORS
TEST REACTORS
THERMAL REACTORS
URANIUM COMPOUNDS
WATER COOLED REACTORS
WATER MODERATED REACTORS
WIND