Why is nuclear waste enclosed in lead and cement casks and buried deep under ground?
the cement makes the nuclear material inert.
the lead, cement and deep earth cover act as radiation shields.
the cement reacts with the waste to initiate the nuclear process.
the cement takes on the properties of the fuel, creating more fuel.

The nuclear waste was enclosed in lead and cement casks and buried deep under ground because the lead, cement and deep earth cover act as radiation shields.

Option B

Explanation:

Nuclear waste releases radiation as the radioactive source will not be disintegrating completely even after its usage was ended. As the half life time of any radioactive source is very high, complete disintegration of radioactive sources will take time to decay fully.

So, we should use shielding materials through which the intensity of the radiations will not be able to penetrate to affect the human life. As it is known that the three types of radiations like alpha, beta and gamma can be stopped by varying the shielding materials.

So, a nuclear waste is generally casketed in lead and cement tanks and buried deep under ground so that the radiations will not be able to penetrate this much distance and affect human life.