ECCS

Question 1

What is the difference between a leak versus a LOCA

Answer 1

LEAK less than the capability of the charging system ( both charging pumps at maximum flow and letdown is isolated)
LOCA Greater than the capability of the charging system.

Question 2

What are the phases of a large break LOCA?

Answer 2

Blowdown. Ends when RCS pressure = to containment

Refill. Ends when ECCS fills the bottom of the vessel and liquid level reaches the bottom of the fuel rods.

Reflood. Ends when vessel has been filled with water such that the core temperature rise has stopped and temperatures have been reduced to long term decay heat values.

Long term recirculation. RHR and CTS suction from recirc sump. SI and CCP suction from RHR.

Question 3

What are the phases of a small break LOCA?

Answer 3

Blowdown.
Re flood
Long term recirculation.

Question 4

What pressure do the different ECCS systems inject?

Answer 4

Charging pumps - 2500psi.
Safety injection pumps - 1400psi.
Accumulators - 600psi.
RHR pumps - 150psi.

Question 5

What is the tech spec boron concentration of the RWST and Accumulators?

Answer 5

2400ppm to 2600ppm.

Question 6

What leg does RHR inject into during the injection phase?

Answer 6

The cold legs.

After 7 hours we switch to hot leg injection then back.