P4- Atomic structure

Question 1

Why is alpha less dangerous outside the body? Inside?

Answer 1

• because it cannot penetrate the skin and is easily blocked by a small air gap
• most ionising and they work on very localised areas. So contamination, rather than irradiation, is the major concern when working with alpha sources.
• Beta sources are less damaging inside the body as radiation is absorbed by a wider area, and some passes out of the body altogeter.

Question 2

Describe how radiotherapy can be used to treat cancerous cells?

Answer 2

• since high doses of ionis radiation will kill all living cells, it can be used to treat cancers.
• gr are directly carefully and at just the right dosage to kill cancer cells without damaging too many normal cells. Radiation-emitting implants can be put next to or inside tumours.

Question 3

In a nuclear reactor, what is the purpous of:

• a coolant
• moderator.
• control rods

Why we use heat exchanges from the coolant via heat exchange?

Answer 3

• Coolant and moderator are usually pressurized water
• Moderator- stop the uranium fuel rods from overheating and slow down neutrons to help produce a chain reaction and be absorbed by nuclei- also absorb the thermal energy of the neutrons- heating up and producing steam to turn turbines. MODERATOR CAN ASO BE LIQUID SODIUM, GRAPHITE.
• Control rods- absorb neutrons- they can control the rate of chain reaction.

Heat exchangers: in case coolant water becomes contaminated- leading to contamination or irradiation