Reactor Trips

Question 1

Describe the setpoint, coincidence, interlocks, and protection afforded by the Source Range High Flux Trip.

Answer 1

Greater than 10^5 counts per second
1/2
P-6, P-10
Shutdown reactivity change, start-up accident

Question 2

Describe the setpoint, coincidence, interlocks, and protection afforded by the Intermediate Range High Flux Trip.

Answer 2

Intermediate current equivalent greater than 25% power
1/2
P-10
Start-up accident

Question 3

Describe the setpoint, coincidence, interlocks, and protection afforded by the Power Range High Flux (Low Setpoint) Trip.

Answer 3

Greater than 25% Power Range
2/4
P-10
Start-up accident

Question 4

Describe the setpoint, coincidence, interlocks, and protection afforded by the Power Range High Flux (High Setpoint) Trip.

Answer 4

Greater than 109% Power Range
2/4
None
Overpower

Question 5

Describe the setpoint, coincidence, interlocks, and protection afforded by the Power Range High Positive Flux Rate Trip.

Answer 5

Greater than 5% increase on the Power Range over 2 seconds
2/4
None
Rod Ejection

Question 6

Describe the setpoint, coincidence, interlocks, and protection afforded by the RCP Low Voltage Trip.

Answer 6

77% Nominal Voltage for longer than 1.5s
1/2 RCPs on both Buses
P-7
Anticipatory Loss of Flow, DNB

Question 7

Describe the setpoint, coincidence, interlocks, and protection afforded by the RCP Underfrequency Trip.

Answer 7

57.2 Hz for greater than 0.6 seconds
1/2 RCPs on both PA Buses
P-7
Note that the RCP output breakers also open - this allows the RCP flywheel to spin freely

Question 8

Describe the setpoint, coincidence, interlocks, and protection afforded by the Low RCS Flow trip.

Answer 8

Less than 90% rated flow
2/3 channels in 2/4 loops when greater than 10% RTP
2/3 channels in 1/4 loops when greater than 48% RTP
P-7, P-8
DNB

Question 9

Describe the setpoint, coincidence, interlocks, and protection afforded by the OTDT Trip.

Answer 9

dT greater than 110% +/- penalties
2/4
None
DNB

Question 10

Describe the setpoint, coincidence, interlocks, and protection afforded by the OPDT Trip.

Answer 10

dT greater than 109% - penalties
2/4
None
Excessive kW/ft

Question 11

Describe the setpoint, coincidence, interlocks, and protection afforded by the Pressurizer High Pressure Trip.

Answer 11

Pressurizer Pressure greater than 2385 psig
2/4
None
RCS Overpressure

Question 12

Describe the setpoint, coincidence, interlocks, and protection afforded by the Pressurizer Low Pressure Trip.

Answer 12

Pressurizer Pressure lower than 1885 psig
2/4
P-7
DNB

Question 13

Describe the setpoint, coincidence, interlocks, and protection afforded by the Pressurizer High Level Trip.

Answer 13

Pressurizer Level greater than 92%
2/3
P-7
Prevents water relief through safety valves

Question 14

Describe the setpoint, coincidence, interlocks, and protection afforded by the SG Lo-Lo Level Trip.

Answer 14

When RTP < 10%, if:
CTMT pressure > 1.5 psig and SG level at 20% OR
CTMT pressure < 1.5 psig and SG level at 15%, with a 232s delay
When 10% < RTP < 20%, if:
CTMT pressure > 1.5 psig and SG level at 20% OR
CTMT pressure < 1.5 psig and SG level at 15%, with a 122s delay
When RTP > 20%, if:
CTMT pressure > 1.5 psig and SG level at 20% OR
CTMT pressure < 1.5 psig and SG level at 15%, with no delay
2/4 channels in 1/4 SGs
None
Loss of Heat Sink

Question 15

Describe the setpoint, coincidence, interlocks, and protection afforded by the Turbine Trip.

Answer 15

ETS Oil Pressure < 600 psig, 2/3
OR
Turbine Stop Valves closed, 4/4
P-9
Limits Temperature and Pressure Transients on Reactor Imposed by Turbine Trip

Question 16

Describe the setpoint, coincidence, interlocks, and protection afforded by the Safety Injection Trip.

Answer 16

Any 1 of the following:
1. Low PZR Pressure SI (1849 psig)
2. Low SL Pressure SI (615 psig)
3. High Containment Pressure (3.5 psig)
4. Manual SI
1/2 SI Trains
None
Trips Reactor to Limit Consequences of the Accident