Reactor accident

Plant and animal life are monitored regularly at such faciHties. On the other hand, the potential, however small, of radioactive contamination of the environment in case of a reactor accident in which containment is breached does exist. 

Optimism about economic growth in the period 1960—1975 led to a large number of reactor orders. Many of these were canceled even after partial completion in the period after the 1974 oil crisis, as the result of a reduction in energy demand. Inflation, high interest rates, long constmction periods, and regulatory delays resulted in severe cost overmns. Moreover, the reactor accidents of TMI and, later, Chernobyl produced an atmosphere of pubHc concern. 

The risk to an average individual in the vicinity of a nuclear power plant of prompt fatalities that might result from reactor accidents should not exceed 0.1% of the sum of prompt fatality ri.sks from other accidents to which members of the U.S. population are generally exposed. ... 

The data suggest that iodine will be released, predominantly, as cesium iodide under most postulated light water reactor accident conditions. However, formation of more volatile iodine species (e.g., elemental iodine and organic iodines) is not impossible under certain accident conditions. 

The ingestion dose contributes very little to the dose from a severe reactor accident and is usually not computed. However, the food pathway is a major determinant of bow the exposed area must be treated in the months and years following the accident. If the ground concentration is high, the land may be interdicted from agricultural u.se or grazing. 

CRAC determined the consequences of a reactor accident using meteorological data for six reactor sites. Each site was taken to represent an entire region, and all of the 68 sites of the first 100 reactors were assigned to one of these six regions. Wind. speed and stability for each of the six sites was assumed to be representative of the entire region out to a distance of 500 miles. Wind direction because with so many sites, the wind direction was assumed random, but the population dish ibution for all 68 sites was used. 

The previous chapter described the consequences of a nuclear reactor accident. Chemical process accidents are more varied and do not usually have the energy to melt thick pressure vessels and concrete basemats. The consequences of a chemical process accident that releases a toxic plume, like Bhopal did, are calculated similarly to calculating the dose from inhalation from a radioactive plume but usually calculating chemical process accidents differ from nuclear accidents for which explosions do not occur. 

The mean frequencies of events damaging more than 5% of the reactor core per year were found to be Internal Events 6.7E-5, Fire 1.7E-5, Seismic 1.7E-4, and total 2,5E-4. Thus, within the range of U. S. commercial light water reactors The core damage frequency itself, is only part of the story because many N-Reactor accident sequences damage only a small fraction of the core. The... 

N Reactor accidents are expected at lower fuel temperatures than LWR accidents. The large thermal capacity of the graphite moderator stack, the low melting point of the fuel (1,407"K) and the GSCS contribute to lower accident temperatures which retains heavy metals in the fuel. 

An Approach to Quantitative Safety Goals for Nuclear Power Plants, October 1980. Rasedag, W. F. et al., Regulatory Impact on Nuclear Reactor Accident Source Term Assumptions, June 1981. 

Nuclear reactor accidents d d Pesticides d Uranium mining d Asbestos d PCBs Nuclear weapons... 

D. Mosey, Reactor Accidents, Butterworth Scientific, London. 1990, p. 45. 

The reactor accident at Chernobyl in April 1986 released radionuclides into the atmosphere, mostly between April 26 and May 6. Estimates of quantities released are based on observations of deposition within 30 km of the reactor. Releases in this area were predominantly highly irradiated fuel particles. It is estimated that the discharge of 241Pu through May 6, 1986 was 5,200 TBq (140 kCi), which amounted to 3% of the reactor content of this radionuclide (Askbrant et al. 1996 Pattenden and McKay 1994). The material was released mainly in the lower troposphere. 

While we recognize the major concern attendant on widespread use of nuclear power in particular reactor malfunction, we note that no reactor accident that harmed any member of the public has occurred in any facility meeting international safety standards (Chernobyl did not meet the standards). Eossilfuel pollution from power plants is estimated to cause 40,000 to 70,000 deaths per year in the United States alone. 

There is now a marked pause in the construction and deployment of new nuclear power plants. Although some construction of reactors continues in Asia and Eastern Europe, a de facto moratorium exists in the United States and in most of Europe, while in Sweden and Gennany the governments plan to shut down operating plants before the end of their normal lifetimes. The inhibitions on nuclear power development stem in large measure from environmental concerns, particularly concerns relating to reactor accidents and nuclear wastes. 

The belief that risks from reactor accident are small is based on the past safety record of nuclear reactors, results of on-going probabilistic risk analyses, indicators of improvement in reactor performance, and the prospect of still greater safety in a next generation of nuclear reactors. 

As discussed above, in a world with 4000 well-designed reactors, one would expect less than a 4% chance of a Chemobyl-scale reactor accident per century. If one estimates that such an accident might cause 20,000 eventual cancer deaths, the calculated risk over a century from reactor accidents would be of the order of 800 deaths. Reactors might do better or worse than this, but the anticipated scale of harm is in the ballpark of a thousand deaths per century - with large uncertainties in either direction,... 

Vessel blowdown. The previously mentioned relationships for the critical flow rate of a steam-water mixture can be employed with the conservation of mass and energy for a vessel of fixed volume to determine its time-dependent blowdown properties. The range of problems associated with coolant decompression in water-cooled reactors is quite broad. The types of hypothetical (some are even incredible) reactor accidents may be... 

Anspaugh, L.R., R.J. Catlin, and M. Goldman. 1988. The global impact of the Chernobyl reactor accident. Science 242 1513-1519. 

Brittain, J.E., A. Storruste, and E. Larsen. 1991. Radiocesium in brown trout (Salmo trutta) from a subalpine lake ecosystem after the Chernobyl reactor accident. Jour. Environ. Radioactivity 14 181-191. 

Ioannides, K.G. and A.A. Pakou. 1991. Radioiodine retention in ovine thyroids in northwestern Greece following the reactor accident at Chernobyl. Health Phys. 60 517-521. 

Reactor accidents have been greatly publicized, but there has not been one death associated with an American nuclear reactor accident. However the dependence on automobiles results in more than 40,000 deaths each year. All forms of energy generation, including alternatives like solar and wind involve industrial deaths in the mining, manufacture, and transport of materials they require. Nuclear energy requires the smallest amount of resources and thus has the lowest risk of deaths. 

Conventional nuclear reactors and advanced breeder reactors were America s primary energy strategy since the 1950s to resolve the fossil fuel problem but when a reactor accident occurred in 1979 at Three Mile Island in Pennsylvania, public and investor confidence in nuclear fission dropped. The accident was triggered by the failure of a feedwater pump that supplied water to the steam generators. The backup feedwater pumps were not connected to the system as required, which caused the reactor to heat up. The safety valve then failed to act which allowed a radioactive water and gas leak. This was the worst nuclear power accident in the U.S., but in this accident no one was killed and no one was directly injured. At Three Mile Island faulty instrumentation gave incorrect readings for the... 

Severe reactor-accident release, waste-repository release, land disturbance, and others, if hydrogen is produced via uranium feedstock ... 

Experience from the 1986 Chernobyl reactor accident in the Ukraine shows the potential magnitude and impact of a terrorist attack on a nuclear power plant. The accident involved an explosion in a reactor that releases very high levels of radiation for miles surrounding the reactor site. Low levels of radiation were spread by wind currents throughout Europe and the rest of the world. According to Caldicott 2002,... 

This article does not cover the extensive research carried out to delineate the cause and severity of RPTs possible in nuclear reactor accidents. Although there is not universal agreement, the general consensus is that the superheated liquid concept can explain many of these events and, more importantly, can indicate when RPTs are unlikely to occur in hypothetical reactor accidents. 

Acrylic Polymer Reactor Accident Investigation Lessens Learned and Three Years Later, Michael Gromacki... 

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