Question

1. A negative moderator reactivity coefficient produces what result when coolant temperature decreases? a) Addition of negative reactivity b) Addition of positive reactivity c) No change in reactivity d) None of the above 235 are a) Isotones b) Isotopes c) Isobars d) Isomers temperature coefficient of reactivity is preferred in a reactor design because it means that a) b) c) d) Negative; the reactor won't enter a positive feedback loop Negative; the neutrons are better thermalized at higher temperatures Positive; the reactor will be able to reach higher temperatures Positive; the neutrons will cause more fissions on average 4. In a real reactor system, which of the following processes is isentropic? a) Pumping b) Heating c) Moving the Turbine d) All of the Above e) None of the Above 5. You measure out 16 g of amazium, a substance which becomes massless once it undergoes radioactive decay once. After 24 seconds, you measure the amazium again, and find it is now only 1 g! What is the half-life of amazium? a) 16 seconds b) 2 seconds c) 4 seconds d) 6 seconds e) 12 seconds

Answer 1

Ans 1

Option B is the correct answer

When coolant temperature decreases, the addition of positive reactivity takes place in the reactor because of the characteristic of Doppler broadening in which on increasing the fuel temperature, neutrons are captured in the fuel.

Ans 2

Option C is the correct answer

Both elements have same atomic mass of 235.

These elements are isobars