Steam Generator Water Level Control (RQ-C-4772)

Question 1

What provides backup power to a control group?

A) DCS A or D via Power Distribution Units.
B) DCS B or C via Power Distribution Units.
C) Opposite Train of CRID via ABT
D) Battery bank via ABT

Answer 1

B) DCS B or C via Power Distribution Units.

Question 2

What are the controlling SG water level channels

Answer 2

• 2, 1, 1, 2 (middle channels)

Question 3

While performing a cooldown on Unit 1, the Group 1 steam dumps are opened to control Tave.

The BOP notices that steam generator narrow range levels are suddenly rising.

Which ONE of the following best describes the steam generator response?

A) Some level may change in the riser, but indicated narrow range level is read in the downcomer region.

B) Higher steam demand causes lower pressure. Lower pressure causes steam bubble expansion. Steam bubble expansion in the tube bundle/riser region, displaces water back into the downcomer region, where level is indicated.

C) Higher steam demand lowers SG pressure.

Answer 3

B) Higher steam demand causes lower pressure. Lower pressure causes steam bubble expansion. Steam bubble expansion in the tube bundle/riser region, displaces water back into the downcomer region, where level is indicated.