NUREG-1150
Encyclopedia
NUREG-1150 is an improvement on WASH-1400
and CRAC-II
using the results of plant-specific Probabilistic Risk Assessment
s (PRAs). It determined that the current generation of nuclear power plants exceeds NRC safety goals
.
"This study was a significant turning point in the use of risk-based concepts in the regulatory process and enabled the NRC to greatly improve its methods for assessing containment performance after core damage and accident progression." http://www.epa.gov/fedrgstr/EPA-GENERAL/1995/August/Day-16/pr-541.html However significant, and sometimes unrealistic, conservatisms were applied in this study http://www.psam7.org/Presentation_Thadani-Text.pdf and it is being replaced with a new state-of-the-art study entitled State-of-the-Art Reactor Consequence Analyses
(see below).
Using the data on pages 3-5, 3-7, 4-5 and 4-7 the probability of some U.S. plant having core damage is about 30% over 20 years - this number doesn't include containment failure, which is conservatively estimated at 8% for PWRs (page 3-13, weighting by the probabilities at the bottom) and 84% for BWRs (page 4-14, same technique). Assuming that the 104 current-design (2005) U.S. plants are similar to the two "typical" plants, the chance of a major release of radiation is under 8% every 20 years.
The typical BWR was the Peach Bottom plant
and the typical PWR was the Surry plant.
Parts of NUREG-1150 were compiled by Sandia National Laboratories
, which continues to do such research. http://www.external.ameslab.gov/risk/SNL.html
NUREG-1420 contains the Kouts’ Committee peer review of NUREG-1150.
WASH-1400
WASH-1400, 'The Reactor Safety Study, was a report produced in 1975 for the Nuclear Regulatory Commission by a committee of specialists under Professor Norman Rasmussen. It "generated a storm of criticism in the years following its release"...
and CRAC-II
CRAC-II
CRAC-II is both a computer code and the 1982 report of the simulation results performed by Sandia National Laboratories for the Nuclear Regulatory Commission...
using the results of plant-specific Probabilistic Risk Assessment
Probabilistic risk assessment
Probabilistic risk assessment is a systematic and comprehensive methodology to evaluate risks associated with a complex engineered technological entity ....
s (PRAs). It determined that the current generation of nuclear power plants exceeds NRC safety goals
Nuclear safety
Nuclear safety covers the actions taken to prevent nuclear and radiation accidents or to limit their consequences. This covers nuclear power plants as well as all other nuclear facilities, the transportation of nuclear materials, and the use and storage of nuclear materials for medical, power,...
.
"This study was a significant turning point in the use of risk-based concepts in the regulatory process and enabled the NRC to greatly improve its methods for assessing containment performance after core damage and accident progression." http://www.epa.gov/fedrgstr/EPA-GENERAL/1995/August/Day-16/pr-541.html However significant, and sometimes unrealistic, conservatisms were applied in this study http://www.psam7.org/Presentation_Thadani-Text.pdf and it is being replaced with a new state-of-the-art study entitled State-of-the-Art Reactor Consequence Analyses
State-of-the-Art Reactor Consequence Analyses
The State-of-the-Art Reactor Consequence Analyses is a study of nuclear power plant safety conducted by the Nuclear Regulatory Commission...
(see below).
Results
Results of NUREG-1150 (page 12-3):- Average probability of an individual early fatality per reactor per year:
- NRC Safety Goal: 5 x 10-7fdsafdsafsa
- Typical Pressurized Water Reactor(PWR)Pressurized water reactorPressurized water reactors constitute a large majority of all western nuclear power plants and are one of three types of light water reactor , the other types being boiling water reactors and supercritical water reactors...
: 2 x 10-8 - Typical Boiling Water Reactor(BWR)Boiling water reactorThe boiling water reactor is a type of light water nuclear reactor used for the generation of electrical power. It is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor , also a type of light water nuclear reactor...
: 5 x 10-11 - Average probability of an individual latent cancer death per reactor per year:
- NRC Safety Goal: 2 x 10-6
- Typical PWR: 2 x 10-9
- Typical BWR: 4 x 10-10
Using the data on pages 3-5, 3-7, 4-5 and 4-7 the probability of some U.S. plant having core damage is about 30% over 20 years - this number doesn't include containment failure, which is conservatively estimated at 8% for PWRs (page 3-13, weighting by the probabilities at the bottom) and 84% for BWRs (page 4-14, same technique). Assuming that the 104 current-design (2005) U.S. plants are similar to the two "typical" plants, the chance of a major release of radiation is under 8% every 20 years.
The typical BWR was the Peach Bottom plant
Peach Bottom Nuclear Generating Station
Peach Bottom Atomic Power Station, a nuclear power plant, is located southeast of Harrisburg in Peach Bottom Township, York County, Pennsylvania, on the Susquehanna River on the Maryland border....
and the typical PWR was the Surry plant.
Parts of NUREG-1150 were compiled by Sandia National Laboratories
Sandia National Laboratories
The Sandia National Laboratories, managed and operated by the Sandia Corporation , are two major United States Department of Energy research and development national laboratories....
, which continues to do such research. http://www.external.ameslab.gov/risk/SNL.html
NUREG-1420 contains the Kouts’ Committee peer review of NUREG-1150.
NRC disclaimer of CRAC-II and NUREG-1150
The NRC, which initially conducted the NUREG-1150 study, has issued the following statement:- "The U.S. Nuclear Regulatory Commission has devoted considerable research resources, both in the past and currently, to evaluating accidents and the possible public consequences of severe reactor accidents. The NRC's most recent studies have confirmed that early research into the topic led to extremely conservative consequence analyses that generate invalid results for attempting to quantify the possible effects of very unlikely severe accidents. In particular, these previous studies did not reflect current plant design, operation, accident management strategies or security enhancements. They often used unnecessarily conservative estimates or assumptions concerning possible damage to the reactor core, the possible radioactive contamination that could be released, and possible failures of the reactor vessel and containment buildings. These previous studies also failed to realistically model the effect of emergency preparedness. The NRC staff is currently pursuing a new, state-of-the-art assessment of possible severe accidents and their consequences."
See also
- Nuclear accidents in the United StatesNuclear accidents in the United StatesAccording to a 2010 survey of energy accidents, there have been at least 56 accidents near nuclear reactors in the United States . The most serious of these was the Three Mile Island accident in 1979...
- Nuclear safety in the U.S.
- Nuclear powerNuclear powerNuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...
- Nuclear fuel response to reactor accidents
External links
- Severe Accident Risks: An Assessment for Five U.S. Nuclear Power Plants (NUREG-1150)
- Rasmussen's comparison of WASH-1400 and NUREG-1150
- Realism in Evaluating Nuclear Hazards (2004)
- Generic Environmental Impact Statement for License Renewal of Nuclear Plants (NUREG-1437 Vol. 1)
- Vandellos plant, some Surry results
- Japanese results
- Probabilities of injuries from nuclear power plants