ATS

Question 1

What is the purpose of ATS?

Answer 1

To take information from various transmitters and to provide interlocks and protective features and trips for various systems and provide control room indication for those systems

Question 2

That does the information from ATS help to prevent?

Answer 2

Vessel Overpressure

Prevent uncovering core and flodding separators

Question 3

What will cause the ATS Gross Failure light to come on?

Answer 3

When transmitters are de-energized or disconnected.
Power Lost
Card Removed

Question 4

What are teh minimum components for an ATS Module?

Answer 4

Power supply
Master Trip Unit
Transmitter
Master Trip Relay

Question 5

What does it mean when an ATS Trip Relay is “Normal”? Reverse?

Answer 5

Normal Means relay is energized when parameter is above teh setpoint
Reverse means that relay is energized when parameter is below the setpoint

IE: For -59” RPS Relay - it is normally energized and kept above the low setpoint - when it drops below the -59” level the relay drops out and actuates

Question 6

What are teh conditions of the ATS trip lights when the Trip Switch is in Normal? Reverse?

Answer 6

Normal means the light is on when the relay is energized

Reverse means the light is on when relay is de-energized (unless loss of power).

Question 7

For ATS what is meant by “Normal-Normal”?

Answer 7

Normal Trip Relay and Normal Trip Light OR

Relay Energized above Setpoint and Light on when relay energized

Question 8

What is the basic logic flowpath for ATS?

Answer 8

Output of XT (transmitter) is set to MTU which drives one MTR (Master Trip Relay) and provides signal through an isolator/converter for the MCR indication

In some cases the MTU provides signal to a Slave Trip Unit (STU) which drives one or more slave trip relay

Question 9

What happens to ATS Division instruments if the division power source is lost?

Answer 9

Atleast some of the instruments are de-energized and signal lost. May cause divisional trips

Question 10

What are the power sources for the ATS System?

Answer 10

Div I: AC from MCC28-1 120VAC Dist Pnl
DC from 125vdc 2A-1 (Same scheme for U3)
Div II: AC from MCC29-1 120VAC Dist Pnl
DC from 125 vdc 2B-1 (Same scheme for U3)q

Question 10

What are the power sources for the ATS System?

Answer 10

Div I: AC from MCC28-1 120VAC Dist Pnl
DC from 125vdc 2A-1 (Same scheme for U3)
Div II: AC from MCC29-1 120VAC Dist Pnl
DC from 125 vdc 2B-1 (Same scheme for U3)q

Question 11

What happens with loss of all ATS AC power?

Answer 11

Lose all control room level indication except narrow range because it is backed up by ESS 250vdc

Question 12

Which ATS Trip Units have meters?

Answer 12

Master Trip Units

Question 13

What is the Purpose of the ATS Isolator?

Answer 13

Prevents an issue from a potentially NS MCR component from affecting the SR ATS components

ALSO converts voltage to current to prevent line losses

Question 14

What signals cause the ATS Trouble Alarm?

Answer 14

Gross Failure
Card Out
Power Failure
Card in Test

Question 15

What is the power voltage to the ATS System?

Answer 15

24VDC - supplied by 120vac to the ATS power supply

Question 16

What does the ATS look like with a loss of power?

Answer 16

The local panel has all METERS DOWNSCALE AND LIGHTS OUT

Question 17

What are teh major trips tied to ATS?

Answer 17

RPS Hi Pressure and Lo Level Scram
PCIS Grp 1,2, & 3 Initiation
RR Pp Rx Lo Lvl Trip (NPSH)
HPCI Isolation
SBGT Start opposite train and heater on low flow
Torus to RB Vacuum Breaker