ASD

Question 1

What is the purpose of ASD?

Answer 1

Provide pulse width modulated output at the correct frequency and voltage to drive the RR Pumps

Question 2

What is the input power for the ASD?

Answer 2

Bus 21/22; 31/32 - 4kV into transformer cabinet

Bus 25/26; 35/36 - into Dist. Panel - UPS - PLC Controls

Question 3

What does the ASD Transformer Cabinet do?

Answer 3

Steps down 4kV voltage to 750VAC for use by power cells

Question 4

What component of the ASD acts as the “Brains”?

Answer 4

FPC - Fuse Pre-charge Cabinet

Question 5

What is the purpose of the ASD UPS?

Answer 5

provides 120VAC from the 480VAC DP to the PLCs and NXGs.

Contains battery for short term transients and internal bypass if UPS fails to send DP power directly to PLC

Question 6

What happens on a failure of ASD UPS 1?

Answer 6

If completely fails and no battery power supplied, the other UPS offers redundant power supply

Question 7

What powers the ASD Remote IO and what are their purpose?

Answer 7

THey are powered by the Computer UPS and ESS feed for control room indication, remote control cabinets, and basic descriptipn.

Question 8

Where are the ASD Cabinet Keys located?

Answer 8

Input Cabinet in a lockbox

Question 9

How many PLCs and NXGs are there per ASD?

Answer 9

2 FPC Cabinets per ASD DRIVE - each with 2 PLCs (A&B) and NXGs (A&B)

Question 10

What happens on a failure of A NXG? Failure of B NXG?

Answer 10

A Failure - transfers to B

B failure when on B - ASD Trip

Question 11

What happens to ASD if Fiber Optic Switching Board Fails?

Answer 11

ASD Trip on loss of communication - One of only non-redundant features

Question 12

What is the purpose of the ASD Pre-charge function?

Answer 12

Allows slowly building in 480VAC instead of direct admission of 4kV to extend power cell life.

Question 13

If the ASD Local HMI is in local control, what are the conditions in the COntrol Room?

Answer 13

ASD cannot be controlled from MCR, speed hold is put in.

NONE OF RUNBACKS or SPeed Holds in MCR work

Question 14

How many power cells are there? What is the input voltage?
How many are REQUIRED for FULL power operation?
How many cells lost will cause an ASD Trip?

Answer 14

12 total - 4 per phase - input 750VAC turned into 1000vdc by IGBT
3 cells per phase requried for FULL POWER
ASD trips on 4 cells lost in 1 phase OR 7 total bypassed

Question 15

What happens on an ASD Power Cell Bypass?

Answer 15

ASD disconnects motor, bypasses cell, re-manipulates cood cells, catchs motor as it is slowing down, and speed hold put in
WHOLE THING takes ~250ms and 6% speed lost
ASD trips if cell can’t be bypassed

Question 16

What are the required conditions for the ASD Relay cabinet?

Answer 16

The relays work on a 2/3 voting logic to trip. If 2 out of 3 are lost, it will trip. - powered by 125vdc at 4kv Bus - depending on division.

Question 17

How does the ASD Coolant System Function?

Answer 17

2 pumps - powered off Bus 25/26 with surge tank, temp reg valvs, and bypass valves. cabinet contains deionizer on exterior.
Radiators external to Trailer.

Question 18

How many ASD Coolant Pumps are normally running?

What conditions cause a pump trip and what happens next?

Answer 18

Normally 1 of 2 running. will trip on loss of power or low flow on running pump.
Standby pump starts. If both pumps lost AND a power cell fault or Xfrmer hi temp - ASD TRIP

Question 19

How does conductivity affect the ASD Coolant system?

Answer 19

No conductivity trip, but low conditions required to start.

Question 20

When do the ASD Coolant Fans start?

Answer 20

Auto start based on PLC input. If PLC fails, Fans turn on

Question 21

What conditions of the ASD Coolant Surge tank induce an ASD Trip?

Answer 21

Lo and Lo-Lo level cause ASD trip

Question 22

If the ASD Coolant Trmp Reg valve fails, what is done?

Answer 22

Motor Operated Bypass goes full open

Question 23

What are the Key ASD Trips - associated with 4kV power source?

Answer 23

ATWS Logic (1200psig Rx Press; -59” Rx Level for 9 sec)
RPV Lo Lo Level (-59” from ATS)
LPCI Loop Select
Suction Vlv <90% Open
Disch. Vlv <90% Open
2/3 Relay protective relay trip (DFR, MMR, Basler)
Bus UV/Overcurrent

Question 24

What are the Key ASD Trips from ASD components?

Answer 24

7 power cells total or 4 in one phase bypassed
Failure to bypass failed power cell
Both NXG failure (or just B if on B)
Lo and Lo-lo level in surge tank
Both coolant pump failed AND power Cell fault OR xfmr thermal alrm
Motor Overspeed

Question 25

What happens to ASD On loss of ESS?

Answer 25

Loss of Anti-Cav Runback Logic

Loss of I/O Cabinets on loss of Computer UPS

Question 26

What happens to ASD on loss of COmputer UPS?

Answer 26

Loss of I/O Cabinets when ESS also lost

Question 27

What happens to ASD on loss of single 480VAC? source?

Answer 27

minimal due to redundance

Question 28

What happens to ASD on loss of 125vDC?

Answer 28

Loss of control power and backup relay protection

Question 29

What is the ASD Coolant Pump setpoint?

Answer 29

<90gpm or fault on running pump (also seen if loss of power to running pump) the pumps swap