C11 - CRD

Question 1

How much flow maintained in the CRD flow control station?

Answer 1

60 gpm

Question 2

How much flow is allowed through the flow control valve in the closed position due to mechanical stop?

Answer 2

5 gpm

Question 3

How does flow control valve react to changes in flow?

Answer 3

> 60 gpm valve closed

< 60 gpm valve opens

Question 4

What powers ARI?

Answer 4

E and K

Question 5

What powers the SCRAM valves?

Answer 5

RPS A and B

Question 6

Where are the CRD pumps controlled from?

Answer 6

601 panel and remote shutdown panels

Question 7

What’s the CRD pump trips?

Answer 7

> 6.4” Hg low suction pressure (approx 20’ in the CST)

< 3.0 low oil pressure

ESF load shed

MPD

Question 8

What’s the purpose of the pressure control valve?

Answer 8

maintain drive water pressure 250 psig above Rx pressure

Maintain cooling water pressure < 20 psig about Rx pressure

Question 9

What can high cooling water pressure cause?

Answer 9

Control rod drive

Question 10

What will excessive drive water pressure cause?

Answer 10

internal damage to CRD drive mechanism

Question 11

When does Aux oil pumps start for CRD?

Answer 11

3-5 psig AND pump breaker open

Question 12

When does Aux oil pump trip?

Answer 12

10 psig

Question 13

What’s the purpose of equalizing valves?

Answer 13

Prevents large DP on CRD piston

Question 14

What does the SCRAM air header supply?

Answer 14

Air to SCRAM valves and SCRAM discharge volume (SDV) vent and drain valves, vents air on SCRAM signal

Question 15

What pressures are HCUs charged to?

Answer 15

1250 psig water

1775 psig water/nitrogen

Question 16

What’s the purpose of SCRAM discharge volume (SDV)?

Answer 16

collects water from CRD mechs during SCRAM. it’s normally empty (drains to suppression pool)

Question 17

how many stab valves close to insert and withdraw a control ROD?

Answer 17

Insert - 2 valves close

withdraw - 2 valves close at first (to lift off collet fingers) then 1 valve for withdraw

Question 18

How much flow is required for the process of inserting and withdrawing a control rod (stab valves)

Answer 18

Insert 5.2 gpm

withdraw 4.2 gpm

Question 19

What is the tech spec time for inserting a control rod?

Answer 19

7 seconds

Question 20

when does the alarm come in for HCU pressure?

Answer 20

1600 psig

Question 21

What is the tech spec limit for HCU pressure?

Answer 21

1520 psig

Question 22

What is the alarm, rod block, and SCRAM setpoints for SDV?

Answer 22

Alarm 2.5” 3 gallons

Rod block 32” 13 gallons

SCRAM 64” 26 gallons

Question 23

What’s the purpose of collet fingers?

Answer 23

prevents rod drift, prevents rod from moving downward, allows for incremental adjustments

Question 24

What’s the purpose of the ball-check valve in CRD system?

Answer 24

Allows Rx pressure to SCRAM Rx with loss of CRD pressure used in HCU failure

Question 25

What’s the purpose of the velocity limiter?

Answer 25

Reduced fall rate to 5 ft/s in Rod drop accident to protect fuel (excessive reactivity)

Question 26

What’s the coupling spud?

Answer 26

connects rod to mech

Question 27

What slows down the rod after a SCRAM?

Answer 27

Buffer piston

Question 28

What happens if under piston line breaks?

Answer 28

Nothing (Collet fingers hold it in place)

Question 29

What happens if over piston (P-over) ruptures?

Answer 29

Rod inserts with cooling water (control rod drift)