Question

"Sr is both a product of radioactive fallout and a radioactive waste in a nuclear reactor. This radioisotope is a \(\beta^{-}\) emitter with a half-life of 27.7 years. Suggest reasons why \(^{90} \mathrm{Sr}\) is such a potentially hazardous substance.

Short answer

Strontium-90 is a potentially hazardous substance due to its properties. It emits beta radiation during decay, transforming into a different radioactive element. Moreover, it has a long half-life of 27.7 years, implying a prolonged period of radiation. Lastly, when Strontium-90 enters the body, it can mimic calcium and get deposited in bones, posing significant health risks, including cancers and leukemia.

Step-by-step solution

Understand the nature of Strontium-90

Strontium-90 is a radioactive isotope. It undergoes beta decay, which results in emission of an electron, transforming the atom into a different element. In this case, Strontium-90 becomes Yttrium-90 through beta decay.

Grasp the significance of half-life

The half-life of a radioactive substance is the time it takes for half of the atoms in a sample to decay. Strontium-90 has a half-life of 27.7 years, which means it remains radioactive for a long period. This prolonged radioactivity contributes to its potential hazard.

Recognize the biohazardous nature of Strontium-90

Strontium-90 has similar chemical properties to calcium. This means that when it enters the body, it can be mistaken for calcium and become deposited in bones and teeth. The radioactive decay of Strontium-90 in the body can damage bone marrow and cells in the bone tissue, causing cancers, leukemia, and other health issues.

Key concepts

Radioactive Decay

When we discuss radioactive decay, we are referring to the process by which an unstable atomic nucleus loses energy by emitting radiation. This process occurs naturally and results in the transformation of one element into another. In the case of Strontium-90, it emits beta particles, which are actually high-energy electrons.
Radioactive decay is a fundamental concept not only in nuclear chemistry but also in physics. Different types of decay include alpha, beta, and gamma decay, each releasing different particles and energy.
Strontium-90 specifically undergoes beta decay, changing into Yttrium-90, which is crucial in understanding its properties and hazards. This transformation is part of a decay chain that continues until a stable element is formed. Therefore, understanding the type of decay a radioactive isotope undergoes helps in assessing its potential risk.

Half-life

The term 'half-life' is used to describe the time required for half of the radioactive atoms in a sample to decay. For Strontium-90, the half-life is 27.7 years, indicating that it stays active for a considerably long time.
This prolonged half-life means that even after several decades, Strontium-90 can still represent a significant risk as it continues to emit radiation.
In practical terms, the half-life helps scientists and engineers in waste management and environmental studies to predict how long a radioactive substance will remain hazardous. Consequently, materials with long half-lives require careful handling and long-term storage solutions.

Beta Decay

Beta decay is a type of radioactive decay where a beta particle, which is an electron or positron, is emitted from an atomic nucleus. For Strontium-90, specifically, beta-minus decay occurs.
During beta-minus decay, a neutron in the nucleus of Strontium-90 is transformed into a proton, releasing an electron (beta particle) and an antineutrino. This process changes Strontium-90 into Yttrium-90 and alters its atomic structure.
The emitted beta particles are capable of penetrating materials and biological tissues, making them particularly hazardous if ingested. Therefore, understanding beta decay is vital for comprehending the risks associated with radioactive isotopes like Strontium-90.

Nuclear Reactor Waste

Nuclear reactor waste comprises materials that remain radioactive and hazardous for long periods after use in a nuclear reactor. Strontium-90 is a common component of this waste.
The hazardous nature of nuclear reactor waste like Strontium-90 is due to its long-term radioactivity and potential to cause environmental contamination if not properly contained. The radiation poses threats not only to the environment but also to human health.
This waste requires stringent storage protocols and advanced disposal technologies to isolate it from living organisms and prevent radiation exposure. Understanding how Strontium-90 fits into the broader category of nuclear waste highlights the need for responsible handling of these materials.

Radioactive Isotopes

Radioactive isotopes, or radioisotopes, are atoms with unstable nuclei that release radiation as they decay into more stable forms. Strontium-90 is one such isotope, making it an important example to study.
Radioisotopes have various applications in medicine, industry, and research. However, those that show long-lasting radioactive decay, like Strontium-90, can pose significant health risks.
Being informed about radioactive isotopes is crucial for both their beneficial uses and understanding the dangers associated with them, especially when these isotopes are found as by-products of nuclear activities.