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High-level waste (HLW) accounts for less than 1% of the total volume of radioactive waste in the UK but represents over 95% of the total radioactivity.
Answer: True
In the UK, high-level waste (HLW) constitutes a small volume but contains the vast majority of the total radioactivity, as detailed in the provided data.
The half-life of a radionuclide directly correlates with its radiation intensity, meaning longer-lived isotopes emit more intense radiation.
Answer: False
The half-life of a radionuclide is inversely proportional to its radiation intensity; longer-lived isotopes emit much less intense radiation than short-lived isotopes, although they remain radioactive for longer periods.
Exposure to ionizing radiation from radioactive waste carries a 5.5% risk of developing cancer per sievert of dose.
Answer: True
Regulatory agencies estimate a 5.5% risk of developing cancer per sievert of dose from exposure to ionizing radiation, assuming a linear relationship between risk and dose.
Intermediate-level waste (ILW) requires both cooling and shielding due to its intense radioactivity and significant decay heat.
Answer: False
Intermediate-level waste (ILW) requires shielding but does not generate significant decay heat that necessitates cooling, unlike high-level waste (HLW).
The average annual radiation exposure from natural radioisotopes worldwide is approximately 20 millisieverts (mSv) per person.
Answer: False
The average annual radiation exposure from natural radioisotopes worldwide is 2.0 millisieverts (mSv) per person, not 20 mSv.
Which classification of radioactive waste is intensely radioactive, generates significant decay heat, and requires both cooling and shielding?
Answer: High-level waste (HLW)
High-level waste (HLW) is characterized by its intense radioactivity, significant decay heat generation, and the necessity for both cooling and shielding during management.
What is the primary factor determining how long radioactive waste must be stored?
Answer: The specific type of waste and the radioactive isotopes it contains.
The duration of radioactive waste storage is primarily dictated by the specific type of waste and the radioactive isotopes it contains, due to their varying half-lives.
Which of the following statements accurately describes the relationship between a radionuclide's half-life and its radiation intensity?
Answer: Long-lived isotopes emit much less intense radiation than short-lived isotopes.
A radionuclide's half-life is inversely proportional to its radiation intensity; long-lived isotopes emit significantly less intense radiation than short-lived isotopes.
What is a potential health impact of exposure to ionizing radiation from radioactive waste, as stated in the source?
Answer: A 5.5% risk of developing cancer per sievert of dose.
Exposure to ionizing radiation from radioactive waste is associated with a 5.5% risk of developing cancer per sievert of dose, according to regulatory agencies.
Why is iodine-131 considered more harmful than caesium-137, despite caesium-137 having a longer half-life?
Answer: Iodine-131 concentrates in the thyroid gland, while caesium-137 is rapidly excreted.
Iodine-131 is considered more harmful than caesium-137 because its pharmacokinetics lead to its concentration in the thyroid gland, whereas water-soluble caesium-137 is rapidly excreted from the body.
What percentage of the total volume of radioactive waste in the UK does low-level waste (LLW) constitute?
Answer: Approximately 94%
In the UK, low-level waste (LLW) constitutes approximately 94% of the total volume of radioactive waste.
What is the typical disposal method for most low-level waste (LLW)?
Answer: Shallow land burial, often after compaction or incineration.
Most low-level waste (LLW) is typically managed through shallow land burial, often after compaction or incineration to reduce its volume.
What distinguishes intermediate-level waste (ILW) from high-level waste (HLW)?
Answer: ILW requires shielding but does not require cooling, unlike HLW.
Intermediate-level waste (ILW) is distinguished from high-level waste (HLW) by its requirement for shielding without the need for cooling, as it does not generate significant decay heat.
As of 2010, approximately how many tonnes of high-level waste (HLW) were stored worldwide?
Answer: 250,000 tonnes
As of 2010, an estimated 250,000 tonnes of high-level waste (HLW) were stored worldwide.
According to U.S. regulations, what defines transuranic waste (TRUW)?
Answer: Waste contaminated with alpha-emitting transuranic radionuclides with half-lives greater than 20 years and concentrations exceeding 100 nCi/g.
Under U.S. regulations, transuranic waste (TRUW) is defined as waste contaminated with alpha-emitting transuranic radionuclides having half-lives greater than 20 years and concentrations exceeding 100 nCi/g.
Radioactive waste is exclusively generated from nuclear power generation and nuclear weapons reprocessing.
Answer: False
Radioactive waste originates from a broader range of activities, including nuclear medicine, nuclear research, and rare-earth mining, in addition to nuclear power generation and weapons reprocessing.
Spent nuclear fuel must be replaced in a reactor primarily because all fissile material has been consumed.
Answer: False
Spent nuclear fuel is replaced not because all fissile material is consumed, but because fission products, acting as neutron poisons, accumulate and absorb too many neutrons, thereby halting the nuclear chain reaction.
Depleted uranium is primarily composed of uranium-235 and is mainly used as reactor fuel.
Answer: False
Depleted uranium (DU) is primarily composed of uranium-238 with a reduced uranium-235 content and is used for its high density in applications like anti-tank shells and sailboat keels, or in MOX fuel, not primarily as reactor fuel in its depleted form.
Technologically enhanced naturally occurring radioactive material (TENORM) is regulated with the same strictness as nuclear reactor waste due to comparable radiological risks.
Answer: False
Despite posing comparable radiological risks, Technologically Enhanced Naturally Occurring Radioactive Material (TENORM) is not regulated as restrictively as nuclear reactor waste.
Uranium mill tailings are highly radioactive and contain only radionuclides, posing no chemical hazards.
Answer: False
Uranium mill tailings, while containing long-lived radionuclides, are not highly radioactive and also pose chemical hazards due to the presence of heavy metals like lead and arsenic.
The radioactivity of fly ash from coal power plants is generally considered less of a concern than that from nuclear power plants due to its lower overall activity.
Answer: False
While coal fly ash has lower overall activity than nuclear waste, its radioactivity is a greater concern because it can be inhaled. Population exposure from coal power plants is significantly higher than from nuclear power plants.
Sulfate scale from oil wells can be rich in radium, and radon is often present in the water, oil, and gas from wells.
Answer: True
Residues from the oil and gas industry, such as sulfate scale from oil wells, frequently contain radium, and radon is often present in the associated water, oil, and gas.
The in-growth of Americium-241 from Plutonium-241 decay is a significant problem in nuclear weapons decommissioning waste due to its gamma and alpha emissions.
Answer: True
The in-growth of Americium-241 from Plutonium-241 decay is a significant concern in nuclear weapons decommissioning waste because Am-241 is both a gamma and alpha emitter, increasing worker exposure and generating heat.
From which of the following activities does radioactive waste primarily originate?
Answer: Nuclear medicine, nuclear research, and rare-earth mining.
Radioactive waste originates from a diverse set of activities, including nuclear medicine, nuclear research, and rare-earth mining, in addition to nuclear power generation and weapons reprocessing.
What is depleted uranium (DU) primarily composed of?
Answer: Uranium-238 isotope with a reduced uranium-235 content.
Depleted uranium (DU) is primarily composed of the uranium-238 isotope, with a significantly reduced content of uranium-235.
Why must spent nuclear fuel be replaced in a reactor even if it still contains fissile material?
Answer: Fission products, acting as neutron poisons, build up and halt the chain reaction.
Spent nuclear fuel must be replaced because the accumulation of fission products, which act as neutron poisons, absorbs too many neutrons, thereby impeding the nuclear chain reaction and making the fuel inefficient.
How does the use of thorium in nuclear fuels affect the long-term radioactivity of spent nuclear fuel (SNF)?
Answer: It maintains a higher activity level in the long term compared to MOX fuel without thorium.
The use of thorium in nuclear fuels leads to the production of uranium-233, whose decay maintains a higher long-term activity level in spent nuclear fuel compared to MOX fuel without thorium.
What types of radioactive materials are typically found in waste from nuclear weapons decommissioning?
Answer: Alpha-emitting actinides like plutonium-239.
Waste from nuclear weapons decommissioning typically contains alpha-emitting actinides such as plutonium-239, which is a fissile material used in nuclear bombs.
What is 'legacy waste' in the United States?
Answer: Radioactivity and contamination from historic activities like radium industry and military programs.
'Legacy waste' in the United States refers to radioactivity and contamination at numerous sites resulting from historic activities such as the radium industry, uranium mining, and military programs.
Which of the following is a common short-lived gamma emitter found in radioactive medical waste?
Answer: Technetium-99m
Technetium-99m is a common short-lived gamma emitter frequently found in radioactive medical waste.
What is the primary difference in regulation between Technologically Enhanced Naturally Occurring Radioactive Material (TENORM) and nuclear reactor waste?
Answer: TENORM is not regulated as restrictively as nuclear reactor waste.
The primary difference in regulation is that Technologically Enhanced Naturally Occurring Radioactive Material (TENORM) is not regulated as restrictively as nuclear reactor waste, despite comparable radiological risks.
What hazardous components, besides radionuclides, are often found in uranium mill tailings?
Answer: Chemically hazardous heavy metals such as lead and arsenic.
Uranium mill tailings often contain chemically hazardous heavy metals such as lead and arsenic, in addition to radionuclides.
After a few thousand years, which two long-lived fission products primarily dominate the radioactivity in spent fuel?
Answer: Technetium-99 and Iodine-129.
After several millennia, the radioactivity in spent fuel is primarily dominated by the long-lived fission products Technetium-99 and Iodine-129.
What is the significance of Americium-241 (Am-241) in nuclear weapons decommissioning waste?
Answer: It forms from Plutonium-241 decay and is a gamma and alpha emitter, increasing worker exposure and generating heat.
Americium-241 (Am-241) is significant in nuclear weapons decommissioning waste because it forms from Plutonium-241 decay and, as a gamma and alpha emitter, increases worker exposure and generates heat.
What is the estimated annual release of uranium and thorium radioisotopes from coal combustion globally, as predicted by ORNL for 1937-2040?
Answer: 2.9 million tonnes.
The Oak Ridge National Laboratory (ORNL) predicted that the cumulative annual release of uranium and thorium radioisotopes from global coal combustion would amount to 2.9 million tonnes over the period from 1937 to 2040.
Nuclear reprocessing allows for the recycling of approximately 96% of spent nuclear fuel.
Answer: True
Nuclear reprocessing enables the recycling of approximately 96% of spent nuclear fuel into new uranium-based and mixed-oxide (MOX) fuels.
Ion exchange is a method used for treating high-level radioactive wastes to concentrate radioactivity into a smaller volume.
Answer: False
Ion exchange is a method commonly used for treating medium active radioactive wastes to concentrate radioactivity into a smaller volume, not typically high-level wastes.
What percentage of spent nuclear fuel can be recycled back into uranium-based and mixed-oxide (MOX) fuels through reprocessing?
Answer: Approximately 96%
Nuclear reprocessing allows for the recycling of approximately 96% of spent nuclear fuel into new uranium-based and mixed-oxide (MOX) fuels.
What is vitrification primarily used for in radioactive waste management?
Answer: Stabilizing high-level radioactive waste into a water-resistant glass matrix for long-term storage.
Vitrification is primarily used in radioactive waste management to stabilize high-level radioactive waste into a durable, water-resistant glass matrix for long-term storage.
What is an alternative method to vitrification for stabilizing radioactive waste, as mentioned in the source?
Answer: Direct incorporation into a phosphate-based crystalline ceramic host.
An alternative method to vitrification for stabilizing radioactive waste is direct incorporation into a phosphate-based crystalline ceramic host, which offers stability and low porosity.
How is ion exchange typically used in the initial treatment of medium active radioactive wastes?
Answer: To concentrate radioactivity into a smaller volume using substances like ferric hydroxide floc.
Ion exchange is typically used in the initial treatment of medium active radioactive wastes to concentrate radioactivity into a smaller volume, often employing substances like ferric hydroxide floc.
What is Synroc, and what are its key mineral components for immobilizing radioactive waste?
Answer: A synthetic rock developed in Australia, composed of hollandite, zirconolite, and perovskite.
Synroc, or synthetic rock, is an Australian-developed method for immobilizing radioactive waste, composed of key mineral components such as hollandite, zirconolite, and perovskite.
As of 2019, several dedicated civilian high-level nuclear waste sites are fully operational globally.
Answer: False
As of 2019, no dedicated civilian high-level nuclear waste site was fully operational, though several countries are in advanced planning or construction phases.
The 'Remix & Return' approach is suitable for unreprocessed spent reactor fuel because it reduces the toxicity of all radioactive elements.
Answer: False
The 'Remix & Return' approach is unsuitable for unreprocessed spent reactor fuel due to the presence of highly toxic radioactive elements like plutonium, which it does not reduce.
Dry cask storage is a method for above-ground disposal of radioactive waste that keeps the waste easily retrievable.
Answer: True
Dry cask storage is an above-ground method for radioactive waste that offers the advantage of keeping the waste easily retrievable for potential future management options.
The scientific consensus supports ocean dumping as an appropriate and safe means of isolating high-level, long-lived radioactive waste.
Answer: False
The scientific consensus supports deep geological formations as an appropriate and safe means of isolating high-level, long-lived radioactive waste, while ocean dumping is prohibited by international agreements.
Space disposal of nuclear waste is considered a practical and low-risk option for managing large volumes of radioactive material.
Answer: False
Space disposal of nuclear waste is considered impractical and high-risk due to the potential for catastrophic launch failures, the immense volume of waste requiring disposal, and economic and international agreement complexities.
The proposed land-based subductive waste disposal method is prohibited by international agreements, similar to ocean dumping.
Answer: False
The proposed land-based subductive waste disposal method is considered viable because it is not prohibited by international agreements, unlike ocean dumping.
Where is transuranic waste (TRUW) from military facilities in the United States currently disposed of?
Answer: At the Waste Isolation Pilot Plant (WIPP) in New Mexico.
Transuranic waste (TRUW) from U.S. military facilities is currently disposed of at the Waste Isolation Pilot Plant (WIPP) in New Mexico.
What is the typical timeframe considered for managing radioactive waste, and what is the practical study limit for planning and cost evaluations?
Answer: 10,000 to 1,000,000 years for management, up to 100 years for practical studies.
The typical timeframe for managing radioactive waste ranges from 10,000 to 1,000,000 years, but practical studies for planning and cost evaluations usually consider only up to 100 years.
What is the basic concept behind deep geological repositories for high-level radioactive waste?
Answer: Burying waste deep underground in stable geological formations to permanently isolate it from the human environment.
The basic concept of deep geological repositories is to permanently isolate high-level radioactive waste by burying it deep underground in stable geological formations, relying on natural barriers for confinement.
Why did Cumbria county council reject UK government proposals for an underground nuclear waste dump?
Answer: Independent geologists presented evidence that the fractured geological strata of the county made it unsuitable.
Cumbria county council rejected proposals for an underground nuclear waste dump after independent geologists provided evidence that the county's fractured geological strata were unsuitable for safe, long-term containment.
What is the scientific consensus regarding the disposal of high-level, long-lived radioactive waste?
Answer: Deep geological formations are considered an appropriate and safe means of isolation.
There is a broad scientific and technical consensus that deep geological formations are an appropriate and safe means of isolating high-level, long-lived radioactive waste from the biosphere for very long timescales.
Nuclear transmutation aims to convert unstable atoms into other, less-harmful or shorter-lived, nuclear waste through neutron capture.
Answer: True
Nuclear transmutation is a process designed to reduce the hazard of nuclear waste by converting unstable atoms into less harmful or shorter-lived isotopes through neutron capture.
President Carter banned transmutation in the United States in 1977 due to economic losses, and the ban remains in effect today.
Answer: False
President Carter banned transmutation in 1977 due to plutonium proliferation concerns, not economic losses, and the ban was rescinded by President Reagan in 1981.
The 'Nuclear Assisted Hydrocarbon Production Method' proposes using nuclear waste's thermal flux to extract hydrocarbons and hydrogen from unconventional oil formations.
Answer: True
The 'Nuclear Assisted Hydrocarbon Production Method' is a patented concept that proposes using the thermal flux from nuclear waste stored in unconventional oil formations to fracture the formation and facilitate the extraction of hydrocarbons and hydrogen.
How can Generation IV reactors contribute to reducing radioactive waste accumulation?
Answer: They are designed to output less waste per unit of power generated and can consume MOX fuel.
Generation IV reactors are designed to reduce radioactive waste accumulation by producing less waste per unit of power and by being capable of consuming MOX fuel, which is manufactured from recycled spent fuel.
Which algae have shown promise in the bioremediation of strontium-90 due to their selectivity for strontium?
Answer: Scenedesmus spinosus and Closterium moniliferum.
Algae species such as Scenedesmus spinosus and Closterium moniliferum have demonstrated promise in the bioremediation of strontium-90 due to their selective biosorption capacity for strontium.
What is Nobel Prize winner Gérard Mourou's proposal for using lasers in nuclear waste transmutation?
Answer: Using lasers to accelerate deuterons or protons to cause fusion or spallation events for transmutation.
Nobel Prize winner Gérard Mourou proposed using high-energy laser pulses to accelerate deuterons or protons, inducing fusion or spallation events for nuclear waste transmutation.
Beyond disposal, what is one way radioactive isotopes from nuclear waste can be re-used?
Answer: For industrial uses such as food irradiation and in radioisotope thermoelectric generators (RTGs).
Radioactive isotopes from nuclear waste can be re-used for industrial applications such as food irradiation and in radioisotope thermoelectric generators (RTGs).
The International Atomic Energy Agency (IAEA) is solely responsible for the direct disposal of all radioactive waste globally.
Answer: False
The IAEA's role is to regulate storage and disposal through its safety standards and to review national management approaches, not to directly manage global radioactive waste disposal.
European countries generally have less stringent radiation exposure limits for high-level nuclear waste facilities compared to the United States.
Answer: False
Many European countries have significantly more stringent risk or dose limits for public exposure to radiation from future high-level nuclear waste facilities compared to those proposed in the United States.
The 'Ndrangheta mafia clan has been investigated for allegedly trafficking and illegally dumping nuclear waste in various countries.
Answer: True
Italian authorities are investigating the 'Ndrangheta mafia clan for alleged involvement in trafficking and illegally dumping nuclear waste in countries such as Somalia and off the Calabrian coast.
The trefoil symbol is a specific warning sign exclusively for high-level radioactive waste.
Answer: False
The trefoil symbol is a universally recognized hazard warning sign for the presence of ionizing radiation in general, not exclusively for high-level radioactive waste.
The 2007 ISO radioactivity danger symbol is specifically designed for IAEA Category 1, 2, and 3 sources, which are defined as dangerous sources.
Answer: True
The 2007 ISO radioactivity danger symbol is specifically intended for IAEA Category 1, 2, and 3 sources, which are classified as dangerous sources capable of causing death or serious injury.
Mongolia successfully negotiated and established several nuclear-waste facilities with foreign governments in 2011.
Answer: False
Mongolia ceased all negotiations regarding nuclear-waste facilities with foreign governments in September 2011 due to significant public opposition.
What is a key role of the International Atomic Energy Agency (IAEA) in radioactive waste management?
Answer: Regulating storage and disposal through its Radioactive Waste Safety Standards (RADWASS).
A key role of the IAEA is to regulate the storage and disposal of radioactive waste through its Radioactive Waste Safety Standards (RADWASS) and to review national management approaches.
What is the primary proliferation concern associated with high-level radioactive waste?
Answer: The presence of plutonium, which can be used in nuclear weapons.
The primary proliferation concern associated with high-level radioactive waste is the presence of plutonium, which is a fissile material that could potentially be used in nuclear weapons.
Which international agreement prohibits ocean disposal of radioactive waste?
Answer: The London Dumping Convention.
The London Dumping Convention is the international agreement that prohibits the ocean disposal of radioactive waste.
What incident occurred at Lake Karachay in the Soviet Union involving radioactive waste?
Answer: A dust storm blew radioactive material over the surrounding area after the lake partly dried out.
At Lake Karachay in the Soviet Union, a dust storm dispersed radioactive material over the surrounding area after the lake, used for radioactive waste storage, partly dried out.