General facts about radioactive wastes

Essay by jeanie45High School, 10th gradeA, January 2009

download word file, 6 pages 0.0

How can nuclear waste be managed for better future?Radiations are used in many part of the world, in the field of therapy for removing tumors and cancer, used as weapons, produced in industries…etc. Recently, people had been discussed a lot about the nuclear energy which seems to be the best possible solution to solve the ever worsening energy crisis. But despite of all the advantages of using nuclear energy, the major drawback, the release of radiation, still cause people from supporting the use of nuclear energy.

Radiation is the energy releases while the decay of some radioactive isotope’s neutron which are not stable. These energies are released in different forms, which are further classified into Alpha and Beta particles, Gamma rays and neutron radiation. 2type of radiationpenetrates…blocks by…characteristicsAlpha radiationthe skinsheet of paperharmful to lungsBeta radiationinto the bodysheet of aluminum foilGamma raysgo through bodyseveral cm of lead or concrete, or meter of waterneutron radiationgo through the bodymeters of concretethe most powerful among all3The radiations can also be found in the nature, these are called background radiation since soil holds radioactive substances such as uranium, thorium, radium and the radioactive gas radon which is continually escaping to the atmosphere; these-------------------------------------------------------------------------------------------------------footnote:1,2,3 :

are usually considered not harmful since the concentrations are too low. After the radioactive substances gone through the decay process which releases mostof its energy, the remains of it are normally still harmful and these are called radioactive waste, or radwastes, which can be classified into 3 categories: low level waste, intermediate waste, and high level waste.4type of radwastessources of disposalcomprise of ways of disposallow level wastehospitals, laboratory, industries, and nuclear fuel cyclepaper, rags, tools, clothing, filtersburied in shallow landfill sitesintermediate wastereactor decommissioningresins, chemical sludges and reactor components, as well as contaminated materialssolidified in concrete or bitumen or buried in soil and the dept is depend on its time it remain hazardoushigh level wastenuclear reactors, nuclear power plantsused fuel itself and principled waste from reprocessing the fuelVitrification and seal properly in order to store underground.

5-------------------------------------------------------------------------------------------------------Footnote:4: waste can also be classified by their life span. The half life is the time it takes for a given radioactive isotope to lose half of its radioactivity, which decreases with time as these isotopes decay into stable, non-radioactive ones. The rate of decay of an isotope is inversely proportional to its half life; a short half life means that it decays rapidly. 7-------------------------------------------------------------------------------------------------------Footnote:7: to the level that they are hazardous and their life span, different wastes will be treated differently. For low level and intermediate level of waste, “concentrate and concrete” and “dilute and disperse” are the most common ways.

While for high level radwastes, or used reactor fuel, it has to be treated differently with “delay and decay”. For most of the cases, if the high level has a long life span, they will be vitrified by incorporating it into borosilicate (Pyrex) glass which is sealed inside stainless steel canisters for eventual disposal deep underground. 9-------------------------------------------------------------------------------------------------------Footnote:8: way of managing the long-lived high level waste is by reprocessing it and then produces the usable fuel from it. This is usually preferred by most power plants in Japan and Europe. The volume of used fuel occupies about 9 times more than the volume of the processed and vitrified radwastes. During reprocessing; the used fuel will be separated chemically into uranium, plutonium and high-level waste solutions. About 97% of the used fuel can be reused again while only 3% will remain as radwastes. 11But which ever option is chosen, the used fuel has to be stored for several years under water in the reactor sites. The concrete ponds and the water covering the fuel assemblies provide radiation protection, while removing the heat generated during radioactive decay.12↑ Storage pond for spent fuel at UK reprocessing plant 13After vitrification, it is usually followed by all solidification. Solidification is the recently developed technique to store radwastes. It evaporates the liquid radwastes and mixed it with glass forming material which are then melted and poured into robust stainless steel canisters which are then sealed by welding.14These solidified or processed radwastes are stored for 40 to 50 years for the radioactivity to decrease to about one thousandth of its original radioactivity. The disposal for the unprocessed used fuel or vitrified radwastes requires their isolation from the environment for long periods. The most favored method is burial in dry, stable geological formations some 500 meters deep. But in Mexico, purpose-built site for radioactive waste disposal is operating now. After being buried for about 1000 years most of the radioactivity will have decayed.15-------------------------------------------------------------------------------------------------------Footnote:12, 13: main drawback of using nuclear energy is there is the existence of radiation. These radioactive substances, after used, still produce radiations. But these radioactive substances, if not handled properly has the ability to destroy the whole ecosystem of a particular region. Even the management of radwaste are planned with the major concern that no radiations will penetrate the layer of shields to harm the environment, these are still potentially hazardous substances, and no one know whether it will leak one day.

No matter how effectively the precautions are done, accidents still happens, which cause the main issues concerns with nuclear energy and its radiations released. The Chernobyl nuclear accident in April 1986 dwarfs all other sources of accidental pollution. The Baltic Sea, northern Adriatic, North Sea, North West coast of Scotland and Irish Sea were all significantly affected by contaminated rainfall. Fish stocks still showed evidence of caesium (134 & 137) contamination in November 1986, and residual contamination is apparent today. 16Even though Europe is considered as highly educated region compared to the rest of the world, many European Union Citizens still think that “Nuclear energy” is terrible because they don’t know much about it. Many of them have fear toward this unknown energy. Not that they are not properly informed, but they also have wrong impression toward the word “Nuclear energy”. “Are all radioactive waste dangerous?” is a simple question asked to them, even though the answer is false, 79% of them answered yes. 17This cause the major disapproval on nuclear site construction, Across the European Union, Even more than 80% of them agree to the fact that by using nuclear energy, we can reduce our dependence to crude oil, only 37% of interviewees say that they are in favor of energy produced by nuclear power stations, while 55% are against it and 8% express no opinion. 18-------------------------------------------------------------------------------------------------------Footnote:16: concern about nuclear energy and the radioactive leakage is actually not without any reason. Radiation affects living organisms through damage to genes (DNA). Mutations in the structure of DNA can be lethal or crippling. Excessive radiation exposure in humans commonly causes a variety of cancers and birth defects. Much less is known about the effect of radioactive pollution on the marine environments. The current safety regulations assume that limits to protect humans will also protect wildlife. The effects of birth defects affect all the organisms and these will cause a serious disrupt in the ecosystem of a certain region and if with high dose of radiation, the ecosystem might be totally destroyed as well. 19In order to set legal protection to all the organisms, laws and regulations are set up to restrict illegal and harmful acts of different communities from contaminating our earth. Sea contamination from nuclear weapons testing began during WWII. Halted under treaty by the USA, USSR and UK in 1963, and continued by France and China until 1974. Sea dumping began in 1946, and continued until a global ban on sea disposal of all solid waste was introduced in 1994. The environmental impact of historical dump sites is unknown, but leaking containers are to likely contaminate marine sediments with a direct impact on bottom dwelling organisms and filter feeders. 20Even I do think that nuclear energy can help human to get rid of the energy crisis that are troubling us now, I still think that we are not so prepared now. As what I had understood up till now, I think we are not yet really well prepared to handle these powerful substances. When I researched “Nuclear Accident” in research engines, the researches shown are numerous that I cannot finished all. The human error never stopped since the first day we study to use radioactive substances to generate energy. Maybe one day, when every detailed thing is controlled by computer and 100% avoid human error, I will think that we are prepared. I think that the management that we do now is good enough since we didn’t harm any organism or contaminate the environment. I was researching one day to find whether there are other ways to treat radwaste and I came across one message from a forum saying that we can transport the radwaste to the space by an auto-piloted spacecraft. It seems to be a good idea except that it’s a bit unethical to pollute the space just so that our planet didn’t get polluted.