GFES

Question 1

What is Differential Rod Worth?

Answer 1

The change in REACTIVITY PER UNIT change in rod position

Slope of the IRW curve

Question 2

What is Integral Rod Worth?

Answer 2

The change in REACTIVITY PER TOTAL change in rod position

Sum of DRWs between initial and final rod positions

Point to point

Question 3

What adds the most positive reactivity following a Rx Trip?

Answer 3

FTC - bc of drastic change in fuel temp

Question 4

What is a prompt neutron?

Answer 4

A neutron w a life of 10E-14 seconds or less

Question 5

What is a delayed neutron?

Answer 5

A neutron life of ? 10E-14 secs

Avg 12.5 seconds

Question 6

Which type of neutrons are Rx Power decreases more limited by?

Answer 6

Delayed neutrons

Question 7

What are the pump laws?

Answer 7

Flow Rate : Pump Speed

Discharge Head: Pump Speed ^2

Pump Power: Pump Speed ^3

Question 8

What are the indications of a dead headed pump?

Answer 8

Lower Flow

Low Amps

Pump will over heat

Question 9

What are the indications of Pump Run Out?

Answer 9

High flow

High amps

Question 10

What are the indications of Cavitation?

Answer 10

Low Flow

Amps Fluctuate

Pressure Fluctuates

Question 11

What kind of stress is the result of a heatup?

Answer 11

Compressive stress due to inner wall heating up faster than the outer wall

Question 12

What kind of stress is felt during a Cooldown?

Answer 12

Tensile Stress due to the inner wall cooling down quicker than the outer wall

Question 13

Once the PRT pressure rises to the point that the rupture disc ruptures, what happens to PRZ PORV Outlet Temperature?

Answer 13

Lowers from the saturation temp for 100 psig to the saturation temperature for containment pressure

Question 14

At the EOL, what type of reactivity do MTC and FTC add?

Answer 14

Both add negative reactivity at EOL

Question 15

Explain how a lowering temperature in containment affects indicated PRZ Level.

Answer 15

PRZ Level has a wet ref leg DP indicator.

As temp in containment (ref leg) lowers, it becomes more dense, and weighs more. This means the level in the pressurizer indicates lower for the same initial value

Question 16

Explain how indicated PRZ Level is affected if containment temperature rises. Assume RCS Pressure and Temp remain constant, and that actual level does not change in the PRZ.

Answer 16

Density lowering in the reference leg causes indicated PRZ Level to read higher than actual level.

Question 17

With a negative MTC, how will a raise in steam flow affect reactor power?

Answer 17

Rx Power will increase to a new, higher value.

The increase in steam flow lowers RCS temperature which adds positive reactivity due to the negative MTC.

Question 18

What happens to Differential Rod Worth over core life?

Answer 18

Becomes more negative (worth more) due to a lower boron concentration and a shift in radial flux

Flux shifts to the outer portion of the core, so more rods are exposed to a higher flux

Question 19

What equation is used to determine break flow for a given pressure?

Answer 19

Break Flow : Square Root of DP

Final flow / initial flow : Square Root of (final pressure / initial pressure)

Question 20

If power is lowered by emergency boration with no rod movement, what will happen to axial power distribution?

Answer 20

Shifts toward the top of the core, where Xenon production will be less