Self Study ABNs

Question 1

ABN-121 Solid Plant Malfunction:
Section 2.0: Increasing RCS Pressure

If RHR suction relief valve lifts prior to PORVs, then what might happen?

Answer 1

Relief valves might not re-seat.

Question 2

ABN-121 Solid Plant Malfunction

→What action is taken if an RHR pump tripped?

Answer 2

→go to ABN-104 RHR System Malfunction

Question 3

ABN-121 Solid Plant Malfunction
Section 2.0: Increasing RCS Pressure

What is the Continuous Action Step in Section 2.0?

Answer 3

Action / Expected Response:
Verify RCS pressure is < LTOP and RCP > 200 psid for seals

RNO:
If RCS pressure is rising:
→lower charging flow OR raise letdown flow to lower and stabilize pressure
→if LTOP actuates, ensure PORV closes when pressure is below setpoint

If RCS pressure is lowering:
→raise charging flow OR lower letdown flow to raise and stabilize pressure
→if RCP #1 seal < 200 psid, stop running RCPs

Question 4

ABN-121 Solid Plant Malfunction
Section 3.0: Decreasing RCS Pressure

→What action is taken if a CCP tripped?
→What action is taken if RCS is not intact (if pressure doesn’t rise with charging flow > letdown flow)

Answer 4

→go to ABN-105 CVCS Malfunction

→go to ABN-108 Shutdown Loss of Coolant

Question 5

ABN-121 Solid Plant Malfunction
Section 3.0: Decreasing RCS Pressure

What are steps 1 thru 4 of Section 3.0?

Answer 5

1) verify RCP Seal #1 > 200 psid (continuous action step)

2) verify charging flow = letdown flow

3) check RCS temp stable
RNO: control RCS temp using:
→RHR flow control valve
→CCW flow control valve
→steam dumps
→ARVs

4) verify RCS intact:
→PORVs closed
→no sump alarms
→charging and letdown matched with pressure stable

RNO:
→if RCS pressure < LTOP, ensure PORV closed or close block valve
→raise charging flow > letdown flow; if pressure doesn’t rise, match charging and letdown and go to ABN-108 for RCS leak

Question 6

ABN-701 Source Range Instrument Malfunction
Section 2.0: Source Range Instrumentation Malfunction

What are steps 1 thru 4 of Section 2.0?

What is the RNO?

Answer 6

1) verify NO core alterations, RCS dilution, or startup in progress

2) verify at least one required SR channel operable

3) if the audible count rate was in service prior to the failure, restore by switching to the other SR channel at the audio count rate channel drawer

4) restore both required SR channels operable within 48 hours OR perform Attachment 1 within the following hour

RNO:
if less than P-6 AND less than two required SR channels operable, then suspend all core alterations and positive reactivity additions

Question 7

ABN-701 Source Range Instrument Malfunction

What happens if Source Range control power fuses are removed?

What happens if Source Range instrument power fuses are removed?

Answer 7

Control Power Fuse Removal
→results in a Reactor Trip even with the LEVEL TRIP switch in BYPASS, unless above P-6 AND manually blocked OR unless above P-10

Instrument Power Fuse Removal
→results in a Reactor Trip unless LEVEL TRIP switch in BYPASS, OR above P-6 AND manually blocked, OR above P-10

Question 8

ABN-701 Source Range Instrument Malfunction

What happens if you receive indication of a higher count rate, but you don’t know if it’s valid?

Answer 8

3. The higher count rate indication is assumed to be valid until an ACOT, CHANNEL CALIBRATION, or Intermediate Range cross-reference has confirmed otherwise. With both N-31 and N-32 inoperable, source range neutron flux may be monitored by observing u-NI-50A-2 and u-NI-50B-2 (Gammametrics).

Question 9

ABN-702 Intermediate Range Instrument Malfunction

What happens if Intermediate Range control power fuses are removed?

What happens if Intermediate Range instrument power fuses are removed?

Answer 9

Control Power Fuse Removal
→results in a Reactor Trip even with the LEVEL TRIP switch in BYPASS, unless above P-10 AND manually blocked

Instrument Power Fuse Removal
→results in a Reactor Trip unless the LEVEL TRIP switch is in BYPASS OR unless above P-10 AND manually blocked

Note:
Removing either control OR instrument power fuses could energize Source Ranges when other IR is below P-6 AND NOT blocked by P-10

Question 10

ABN-702 Intermediate Range Instrument Malfunction

What could potentially happen if a reactor shutdown is performed with an IR channel failed high?

Answer 10

An automatic reactor trip will occur if power is lowered below P-10, unless the failed channel’s LEVEL TRIP switch is first placed in BYPASS.

Question 11

ABN-702 Intermediate Range Instrument Malfunction

Question 12

ABN-908 Fuel Handling Accident

What initiates the Containment Ventilation Isolation?

Answer 12

High containment particulate or gas activity will initiate CVI.

Operator verifies / ensures CVI once initiated.

Question 13

ABN-908 Fuel Handling Accident

What is meant by putting the fuel in a safe condition / secured position?

Answer 13

All fuel assemblies are stored in the:
→core
→SFP
→upender (in horizontal position)

Transfer car is in the Fuel Building, AND
Fuel Transfer Tube gate valve is closed.

Question 14

ABN-901 Fire Protection System Alarms or Malfunctions

What initiates the halon release sequence?

Answer 14

Two fire detectors in the CSR go into alarm.

Question 15

ABN-901 Fire Protection System Alarms or Malfunctions

Systems Review Question:
When do the fire protection pumps automatically start?

Answer 15

→Jockey Pump - always on
→Electric Fire Pump X-04 - 142 psig with a 3 second time delay
→Diesel Fire Pump X-05 - 140 psig with a 10 second time delay, or on loss of control power
→Diesel Fire Pump X-06 - 140 psig with a 20 second time delay, or on loss of control power

Note: The Jockey Pump is designed to cycle on and off between 146 psig and 155 psig, but we don’t operate it that way.