Radioactive Wastes Questions in English

(C) $Strontium-90$ is a radioactive isotope that behaves chemically similar to calcium.
Due to this similarity, it is absorbed by the body and deposited in the bones instead of calcium.
Once deposited, it continuously emits ionizing radiation, which damages the bone marrow, $WBC$ production, spleen, lymph nodes, and lungs.
This prolonged exposure can lead to severe health issues, including tumors and bone cancer.

(D) Nuclear power plants are associated with several environmental and safety concerns:
$1$. Thermal pollution: The discharge of hot water from cooling systems into water bodies can harm aquatic life.
$2$. Emission of hazardous radio-nuclides: Accidental leakage or routine emissions can release harmful radioactive materials into the environment.
$3$. Disposal of radioactive waste: Radioactive waste remains hazardous for thousands of years,and its safe,long-term storage is a significant challenge.

(C) Ionising radiation refers to radiation that carries enough energy to liberate electrons from atoms or molecules,thereby ionising them.
$Alpha$ rays,$Beta$ rays,and $Gamma$ rays are high-energy radiations capable of causing ionisation.
$Infrared$ rays are a form of non-ionising electromagnetic radiation with lower energy,which only causes excitation of atoms or molecules rather than ionisation.
Therefore,$Infrared$ rays are not ionising radiation.

(B) Radioactive fallout from nuclear explosions or accidents releases various isotopes into the environment.
$Sr^{90}$ (Strontium-$90$) is a major radioactive isotope produced during nuclear fission.
It is chemically similar to calcium and can be absorbed by plants and subsequently enter the food chain.
When ingested,it accumulates in the bones and teeth of humans and animals,posing a significant health risk as it emits beta radiation.

(A) Strontium-$90$ $(^{90}Sr)$ is considered one of the most dangerous radioactive pollutants for humans.
It is a byproduct of nuclear fission and is chemically similar to calcium.
When released into the environment,it enters the food chain and is absorbed by the body,where it accumulates in bones and teeth.
Because it mimics calcium,it replaces it in bone tissue,leading to long-term exposure to ionizing radiation,which increases the risk of bone cancer and leukemia.

(D) Nuclear pollution is considered the ultimate environmental hazard to mankind.
This is because nuclear radiation has long-lasting,irreversible,and devastating effects on living organisms,including genetic mutations,cancer,and the potential for large-scale destruction of ecosystems that can persist for thousands of years.

(A) Radioactive pollutants emit high-energy ionizing radiation, such as $X$-rays, $\gamma$-rays, and alpha/beta particles.
These radiations can penetrate living cells and cause damage to the genetic material $(DNA)$.
This damage leads to gene mutations, which can result in cancer, birth defects, and various genetic disorders.
Therefore, gene mutation is considered the most adverse effect of radioactive pollution.

(D) Ionizing radiation is radiation that carries enough energy to liberate electrons from atoms or molecules,thereby ionizing them.
$X$-rays and Gamma rays are high-energy electromagnetic radiations that possess sufficient energy to cause ionization.
$UV$-rays are generally considered non-ionizing or weakly ionizing depending on the wavelength,but in the context of standard biological radiation hazards,$X$-rays and Gamma rays are the primary examples of ionizing radiation.
Therefore,both $(A)$ and $(B)$ are correct.

(D) The Chernobyl disaster,which occurred in $1986$ at the Chernobyl Nuclear Power Plant in Ukraine,was a catastrophic nuclear accident.
It resulted in the release of large quantities of radioactive materials into the atmosphere,causing severe environmental and health consequences.
Therefore,the incident is primarily associated with the mismanagement and leakage of radioactive waste and nuclear radiation.
Thus,the correct option is $D$.

(A) Radioactive waste emits ionizing radiation,such as alpha,beta,and gamma rays. Exposure to high levels of ionizing radiation damages the $DNA$ within cells. This damage can lead to mutations that cause cells to divide uncontrollably,resulting in the development of cancer,such as leukemia.

(C) is correct because radioactive waste emits high-energy ionizing radiations (like alpha,beta,and gamma rays) that can damage $DNA$,leading to mutations in living organisms.
$R$ is incorrect because radioactive waste is extremely hazardous and lethal to human health,causing severe diseases like cancer and genetic disorders,rather than being advantageous.

(D) Relative Biological Effectiveness $(RBE)$ is a term used in radiobiology to compare the effectiveness of different types of ionizing radiation in causing biological damage.
It is defined as the ratio of the absorbed dose of a reference radiation (usually $250 \ keV$ $X$-rays) to the absorbed dose of the radiation in question that produces the same biological effect.
Therefore,$(RBE)$ is directly associated with the damage caused by ionizing radiation.

(D) Exposure to high levels of ionizing radiation causes acute radiation syndrome.
Common symptoms include nausea,vomiting,hair loss (alopecia),and skin damage such as redness (erythema) or ulcers.
Therefore,the combination of skin ulcers,nausea,and hair loss is a characteristic indicator of radiation exposure.

(C) Relative Biological Effectiveness $(RBE)$ is a comparison of the biological effectiveness of different types of ionizing radiation.
It is defined as the ratio of the dose of a standard radiation (usually $250 \text{ kV}$ $X$-rays) to the dose of the radiation in question that produces the same biological effect.
Therefore,$RBE$ is specifically used to measure the damage caused by radiation exposure.

(D) Nuclear waste is extremely radioactive and hazardous to living organisms.
It must be disposed of with extreme caution.
The most accepted and scientifically suitable method for the disposal of nuclear waste is to bury it within rocks deep below the Earth's surface.
This prevents the leakage of radioactive materials into the biosphere and ensures long-term containment.

(N/A) Initially,nuclear energy was considered a non-polluting way for generating electricity. Later,it was realized that it has two very serious inherent problems: $(i)$ accidental leakage,as occurred in the Three Mile Island and Chernobyl incidents,and (ii) safe disposal of radioactive wastes.
Radiation from radioactive waste is extremely damaging to organisms because it causes mutations at a very high rate. High doses of nuclear radiation are lethal,but lower doses create various disorders,the most frequent being cancer.
Therefore,nuclear waste is an extremely potent pollutant and must be dealt with extreme caution.
It is recommended that nuclear waste,after pre-treatment,should be stored in suitably shielded containers (tanks) and buried within the rocks about $500 \ m$ deep below the Earth's surface.

(C) Radioactive waste is considered extremely hazardous and lethal even in small quantities due to the emission of high-energy ionizing radiation. These radiations can cause severe biological damage,including mutations,cancer,and death. While biodegradable and plastic wastes are significant environmental pollutants,radioactive waste poses an immediate and severe threat to life,making it the most lethal among the options provided.

(D) The radioactive waste leakage incident,known as the Three Mile Island accident,occurred in $1979$ in Pennsylvania,$USA$.
It is considered one of the most significant nuclear accidents in the history of the United States.
This event led to widespread concerns regarding the safety and management of nuclear power plants and radioactive waste.

(D) Radioactive waste,especially high-level radioactive waste,emits ionizing radiation such as alpha,beta,and gamma rays.
These radiations have enough energy to damage $DNA$ molecules and alter the genetic structure of organisms.
Exposure to such radiation leads to a high rate of mutations,which can cause severe health issues like cancer and genetic disorders.

(B) Radioactive waste is considered one of the most dangerous and potent pollutants because it emits harmful ionizing radiation that can cause mutations, cancer, and death.
Due to its long half-life and extreme toxicity, radioactive waste must be handled with extreme caution.
According to environmental safety guidelines, high-level radioactive waste should be stored in shielded containers and buried deep within the Earth's crust, typically at a depth of approximately $500$ meters, to prevent radiation leakage into the biosphere.

(D) $(i)$ Nuclear energy is considered a non-polluting way for electricity generation as it does not emit greenhouse gases,although it has the problem of radioactive waste.
$(ii)$ The accidents at Three Mile Island and Chernobyl are well-known historical events involving radioactive leakage.
$(iii)$ Radioactive waste emits ionizing radiation,which can cause genetic mutations and cancer upon prolonged exposure.
$(iv)$ Radioactive waste is not recyclable in the conventional sense; it requires safe disposal in deep underground repositories.
$(v)$ High doses of radiation are lethal as they cause immediate cellular damage and organ failure.
Therefore,statements $(i), (ii), (iii)$ and $(v)$ are correct.

(C) Nuclear energy was initially considered a natural and non-polluting method of electricity generation until the accidents at Three Mile Island and Chernobyl occurred. It is now recognized as a highly potent source of pollution.
The primary causes of radioactive pollution include the leakage of radioactive materials from nuclear power plants and the unsafe disposal of radioactive wastes.

(D) High-level radioactive waste is extremely hazardous. It must be pre-treated to reduce its volume and then stored in shielded,sealed containers. Finally,these containers are buried deep within rocks,typically about $500 \, m$ below the Earth's surface,to prevent radiation leakage into the environment.

(B) Nuclear waste is extremely potent and its radiation causes mutations at a very high rate. Therefore,$A$ is mutation.
At high doses,nuclear radiation is lethal to living organisms.
At low doses,radiation causes various genetic disorders and cancer. Therefore,$B$ is cancer.
Thus,the correct option is $B$ ($A-$mutagenic; $B-$cancer).

(D) Radioactive waste management involves sealing high-level radioactive wastes in concrete-filled drums. These drums are then buried within rocks or discharged into deep oceanic trenches at a depth of about $500 \;m$ to prevent radiation leakage into the biosphere. This method is applicable to all types of radioactive pollutants.

(C) Initially,nuclear energy was hailed as a non-polluting way for generating electricity,but later it was found that it has $2$ very serious problems:
$1$. Accidental leakage.
$2$. Safe disposal of radioactive wastes.
The radiation released from nuclear wastes is extremely damaging to biological organisms as it causes mutations to occur at a very high rate.
It has been recommended that the storage of nuclear wastes,after sufficient pre-treatment,should be done in suitably shielded containers buried within the rocks about $500 \ m$ deep below the earth's surface.

(D) Radioactive waste is considered the most potent pollutant. Its disposal involves several steps:
$1$. Pre-treatment: The waste is processed to reduce its volume and reactivity.
$2$. Shielding: It is stored in containers that are properly shielded to prevent radiation leakage.
$3$. Deep Geological Disposal: The waste is buried within rocks deep below the Earth's surface,typically at a depth of about $500 \ m$,to ensure it does not interact with the biosphere for thousands of years.
Therefore,all the given options are correct methods involved in the management and disposal of radioactive waste.

(B) Initially,nuclear energy was considered as a non-polluting way to generate electricity. However,it was later realized that it has two very serious inherent problems: first,accidental leakage,as occurred in the Three Mile Island and Chernobyl incidents,and second,safe disposal of radioactive wastes.

(D) Nuclear energy has two very serious inherent problems: accidental leakage and safe disposal of radioactive wastes.
Major historical incidents of accidental leakage of nuclear radiation include the Chernobyl disaster (Ukraine,$1986$) and the Three Mile Island accident ($USA$,$1979$).
Therefore,both $A$ and $B$ are correct examples of such incidents.

(D) Radioactive waste is considered an extremely potent pollutant.
$1$. High doses of radiation are lethal to living organisms as they cause immediate cellular damage.
$2$. Lower doses of radiation are known to cause various genetic disorders and mutations at a very high rate.
$3$. Prolonged or frequent exposure to even low levels of radiation is a well-known cause of cancer in humans and other organisms.
Therefore,all the given statements are correct.