CRAC-II
Encyclopedia
CRAC-II is both a computer code (titled Calculation of Reactor Accident Consequences) and the 1982 report of the simulation results performed by Sandia National Laboratories
for the Nuclear Regulatory Commission
. The report is sometimes referred to as the CRAC-II report because it is the computer program used in the calculations, but the report is also known as the 1982 Sandia Siting Study or as NUREG/CR-2239. The computer program MACCS2 has since replaced CRAC-II for consequences of radioactive release.
CRAC-II has been declared to be obsolete and will be replaced by the State-of-the-Art Reactor Consequence Analyses
study.
The CRAC-II simulations calculated the possible consequences of a worst-case accident under worst-case conditions (a so-called "class-9 accident") for a number of different U.S. nuclear power plants. In the Sandia Siting Study, the Indian Point Energy Center
was calculated to have the largest possible consequences for an SST1 (spectrum of source terms) release, with estimated maximum possible casualty numbers of around 50,000 deaths, 150,000 injuries, and property damage of $274 Billion to $314 Billion (based on figures at the time of the report in 1982). The Sandia Siting Study however, is commonly misused as a risk analysis, which it is not. It is a sensitivity analysis of different amounts of radioactive releases and an SST1 release is now generally considered not a credible accident (see below).
Another significant report is the 1991 NUREG-1150
calculations, which is a more-rigorous risk assessment of five U.S. Nuclear Power Plants.
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."
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....
for the Nuclear Regulatory Commission
Nuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
. The report is sometimes referred to as the CRAC-II report because it is the computer program used in the calculations, but the report is also known as the 1982 Sandia Siting Study or as NUREG/CR-2239. The computer program MACCS2 has since replaced CRAC-II for consequences of radioactive release.
CRAC-II has been declared to be obsolete and will be replaced by the 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...
study.
The CRAC-II simulations calculated the possible consequences of a worst-case accident under worst-case conditions (a so-called "class-9 accident") for a number of different U.S. nuclear power plants. In the Sandia Siting Study, the Indian Point Energy Center
Indian Point Energy Center
Indian Point Energy Center is a three-unit nuclear power plant station located in Buchanan, New York just south of Peekskill. It sits on the east bank of the Hudson River, 38 miles north of New York City...
was calculated to have the largest possible consequences for an SST1 (spectrum of source terms) release, with estimated maximum possible casualty numbers of around 50,000 deaths, 150,000 injuries, and property damage of $274 Billion to $314 Billion (based on figures at the time of the report in 1982). The Sandia Siting Study however, is commonly misused as a risk analysis, which it is not. It is a sensitivity analysis of different amounts of radioactive releases and an SST1 release is now generally considered not a credible accident (see below).
Another significant report is the 1991 NUREG-1150
NUREG-1150
NUREG-1150 is an improvement on WASH-1400 and CRAC-II using the results of plant-specific Probabilistic Risk Assessments...
calculations, which is a more-rigorous risk assessment of five U.S. Nuclear Power Plants.
NRC disclaimer of CRAC-II and NUREG-1150
"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 generateinvalid 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...
- WASH-740WASH-740WASH-740, "Theoretical Possibilities and Consequences of Major Accidents in Large Nuclear Power Plants" estimated maximum possible damage from a meltdown with no containment building at a large nuclear reactor. The report was published by the U.S...
(1957) - WASH-1400WASH-1400WASH-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"...
(1975) - NUREG-1150NUREG-1150NUREG-1150 is an improvement on WASH-1400 and CRAC-II using the results of plant-specific Probabilistic Risk Assessments...
(1991)