Explain the concept of half-life of a radioactive substance and state why this concept is important while planning the safe storage of radioactive waste.

Question

Accepted Answer

The half-life of a radioactive isotope is the time required for half of the radioactive atoms in a given sample to decay. It is a fixed, characteristic property of each isotope that cannot be sped up, slowed down, or altered by any physical or chemical treatment. This concept is central to planning safe storage because different isotopes have vastly different half-lives, from fractions of a second to many thousands of years. An isotope with a short half-life loses most of its radioactivity within a comparatively short storage period and can eventually be handled much like ordinary waste, whereas an isotope with a very long half-life remains significantly radioactive for a period that can vastly exceed any human institution's continuous existence -- which is exactly why high-level radioactive waste requires containment strategies (such as deep geological disposal) built to function reliably, essentially without active maintenance, over thousands of years.

✓Final answer

Half-life is the time for half a radioactive sample to decay; it directly determines how long a waste stream must be safely contained, from days for short-half-life isotopes to thousands of years for long-half-life ones.

Same / Similar Concept — real previous-year questions on the same or a closely similar concept, not this exact question.

CBSE 2022Set ANNUAL1 markMCQ
$Q. The most harmful effect of a radioactive pollutant results in$
(a) tuberculosis
(b) polio
(c) hepatitis
(d) gene mutation
›Reveal solutionSolution

Radioactive pollutants most harmfully cause gene mutations, so the answer is (D).

Radioactive pollutants emit ionising radiation, which is highly damaging to living cells. Its most serious and long-lasting effect is on the genetic material: it induces mutations in DNA (gene mutations and chromosomal aberrations) that can lead to cancers and heritable defects passed to future generations. This is why radioactive contamination is considered so hazardous.

Tuberculosis, polio and hepatitis are infectious diseases not caused by radiation, so the correct answer is gene mutation.

✓Final answer
$(D) gene mutation.$
CBSE 2018Set ANNUAL1 mark
$Q. How did generation of electricity by nuclear energy create serious problems in living organisms?$
›Reveal solutionSolution

Nuclear electricity generation poses a risk to living organisms mainly through possible radioactive leaks/accidents and the difficulty of safely managing radioactive waste, both of which can cause radiation-induced harm.

While nuclear power plants generate electricity without directly emitting greenhouse gases, they carry the serious risk of radioactive contamination. Any accidental leakage or a major accident at a nuclear plant can release radioactive material into the environment, and this ionising radiation can damage the DNA of living cells, causing mutations, cancers (such as leukaemia and thyroid cancer) and other radiation sickness in exposed humans, animals and plants — problems that can also affect future generations through germline mutations. In addition, nuclear power generates highly radioactive waste that remains hazardous for very long periods and is extremely difficult to store or dispose of safely, posing an ongoing risk of environmental and biological contamination if containment fails.

✓Final answer
$Nuclear power carries the risk of radioactive leakage/accidents and hazardous long-lived waste, both of which can expose living organisms to ionising radiation, causing DNA damage, mutations and cancers.$

> [!ANSWER]
> Half-life is the time for half a radioactive sample to decay; it directly determines how long a waste stream must be safely contained, from days for short-half-life isotopes to thousands of years for long-half-life ones.

Q.Explain the concept of half-life of a radioactive substance and state why this concept is important while planning the safe storage of radioactive waste.

Concept understanding — Radioactive Waste

Q.Explain the concept of half-life of a radioactive substance and state why this concept is important while planning the safe storage of radioactive waste.

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