United States experience in probabilistic risk assessment for a graphite moderated, channel reactor
- Pacific Northwest Lab., Richland, WA (US)
- Westinghouse Hanford Co., Richland, WA (US)
The United States operated a number of graphite moderated, water cooled, pressure tube (or channel type) reactors at the Hanford Site in Washington State. The last of these reactors to operate was the Hanford N Reactor which was designed to produce steam for the generation of electricity for civilian energy use as well as special nuclear material. In 1982, a review team recommended that a probabilistic risk assessment (PRA) be conducted for the reactor. The basis for this recommendation was that the reactor represented a unique facility and therefore the safety insights gained from operations at other facilities were not directly transferable to it. Furthermore, the reactor was going through a series of upgrades and it was felt that the selection of competing improvements would benefit from a risk perspective to help judge the relative value of these upgrades. The initial Level 1 PRA was initiated just prior to the time of the Chernobyl accident in 1986. After the accident, a limited scope PRA was also conducted. The limited scope PRA was completed in July 1987. The original Level 1 PRA was brought to completion in August 1988 and was followed by complete Level 3 analyses including an evaluation of external initiating events. This paper will focus on the Level 1 effort. The objectives of the Level 1 PRA for N Reactor were: identification of the plant features that are the most important contributors to fuel-damage frequency; development of plant logic models for use in analyzing safety and reliability issues; identification of dominant accident sequences and their frequencies for input into the Level 2/3 PRA and external events analyses; and establishment of a Hanford team with demonstrable expertise in performing risk and reliability analyses.
- Research Organization:
- Pacific Northwest Lab., Richland, WA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 10176803
- Report Number(s):
- PNL-SA-21788; CONF-9306189-3; ON: DE93017662; TRN: 93:018856
- Resource Relation:
- Conference: NE `93: 4th annual scientific and technical conference of the Nuclear Society: nuclear energy and human safety,Nizhni Novgorod (Russian Federation),28 Jun - 2 Jul 1993; Other Information: PBD: Jun 1993
- Country of Publication:
- United States
- Language:
- English
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N-REACTOR
RISK ASSESSMENT
PROBABILITY
FUEL ELEMENT FAILURE
SAFETY ANALYSIS
MATHEMATICAL MODELS
RELIABILITY
REACTOR ACCIDENTS
PERSONNEL
TRAINING
HANFORD RESERVATION
HISTORICAL ASPECTS
DATA ANALYSIS
INFORMATION SYSTEMS
REACTOR CORES
220900
220600
REACTOR SAFETY
RESEARCH
TEST
TRAINING
PRODUCTION
IRRADIATION
MATERIALS TESTING REACTORS