Section 3.8 Electrical Power Systems Flashcards
What is T.S. 3.8.4 DC Sources - Operating?
3.8.4 DC Sources - Operating
The Left Train and Right Train DC electrical power sources shall be OPERABLE.
Modes 1 -4
What is a DC Source?
DC Source
- 1 battery
- 1 directly connected battery charger
- corresponding control equipment and interconnecting cabling
- supplying power to the associated bus
What makes a DC Source Operable?
DC Source Operable
An OPERABLE DC electrical power source requires its battery to be
OPERABLE and connected to the associated DC bus.
When and why do you connect Two Chargers to the same battery?
Two Chargers
T.S. 3.8.4 One required DC electrical power source battery inoperable.
Verify OPERABLE directly connected and functional cross-connected battery chargers are connected supplying power to the affected DC train.
Placing the second battery charger in service provides two benefits:
1) restoration of the capacity to supply a sudden DC power demand,
and 2) restoration of adequate DC power in the affected train as soon
as either AC power distribution system is re-energized following a loss
of offsite power.
What is T.S. 3.8.5 DC Sources - Shutdown?
T.S. 3.8.5 DC Sources - Shutdown
DC electrical power source(s) shall be OPERABLE to support the DC electrical power distribution subsystem(s) required by LCO 3.8.10, “Distribution Systems—Shutdown.”
MODES 5 and 6,
During movement of irradiated fuel assemblies.
What do you do if one or more required DC electrical power sources inoperable?
One or more required DC electrical power sources inoperable.
Immediately declare affected required feature(s) inoperable.
or
Immediately
Suspend CORE ALTERATIONS,
AND
Suspend movement of irradiated fuel assemblies,
AND
Initiate action to suspend operations involving positive reactivity additions,
AND
Initiate action to restore required DC electrical power source(s) to OPERABLE status.
Why are two DC sources required operable during Modes 5 & 6?
3.8.5 DC Sources - Shutdown
Two DC sources are required to ensure availability of an uninterruptable power source for the instrumentation and controls for the Reactor Protective System (RPS).
What is T.S. 3.8.1 AC Sources - Operating?
3.8.1 AC Sources - Operating
The following AC electrical sources shall be OPERABLE:
- Two qualified circuits between the offsite transmission network and the onsite Class 1E AC Electrical Power Distribution System;
and
- Two Diesel Generators (DGs) each capable of supplying one train of the onsite Class 1E AC Electrical Power Distribution System.
MODES 1, 2, 3, and 4.
What do do if one offsite circuit inoperable?
3.8.1 AC Sources - Operating
One offsite circuit inoperable.
Perform offsite source check within 1 hour and then 1 per 8 hours.
What do you do if one DG inoperable?
3.8.1 AC Sources - Operating
Offsite source check within 1 hour and every 8 hours thereafter.
What do you do if three or more AC sources inoperable?
T.S. 3.8.1 AC Sources Operating
Enter LCO 3.0.3. immediately
How long does an EDG Day Tank last?
EDG Day Tank
13.5 hours
What FSAR mechanism initiates a loss of off-site power with the plant off-line? On-line?
FSAR Accident
Offline?
- No specific mechanism for initiating a loss of off-site power when the plant is not on the line is discussed in the FSAR.
Online?
- The loss of off-site power via a perturbation of the transmission grid because of the loss of the plant’s generating capacity.
Those analyses which assume that a loss of off-site power and failure of a
single DG accompany the accident assume what for a time to re-power the bus?
EDG Start and Load
11 seconds from the loss of power until the bus is re-energized. This time includes time for all portions of the circuitry necessary for detecting the undervoltage (relays
and auxiliary relays) and starting the DG. Included in the 11 seconds, the analyses also assume 10 seconds for the DG to start and connect to the bus, and additional time for the sequencer to start each safeguards load.
What is a mode 5 or 6 initiating event for Loss of SD Cooling?
Loss of SD Cooling Initiating Event
Loss of Offsight Power
LPSI pumps are not sequenced on via NSD Sequencer. SIAS would be defeated in Mode 5 and 6.
What are the Qualified Offsite Circuts?
Qualified Offsite Circuts
Safeguards Transformer 1-1 and Startup Transformer 1-2.
Station Power Transformer 1-2 is not qualified as a required source for LCO 3.8.1 since it is not independent of the other two offsite circuits.
What EDG voltage and frequency are requried for operability?
EDG voltage and frequency
- 2280 to 2250 v (95% to 105% rated)
- 59.5 Hz and 61.2 Hz
What is T.S. 3.8.2 AC Sources - Shutdown?
3.8.2 AC Sources - Shutdown
The following AC electrical power sources shall be OPERABLE:
- One qualified circuit between the offsite transmission network and the onsite Class 1E AC electrical power distribution subsystem(s) required by LCO 3.8.10, “Distribution Systems - Shutdown”; and
- One Diesel Generator (DG) capable of supplying one train of the onsite Class 1E AC electrical power distribution subsystem(s) required by LCO 3.8.10.
MODES 5 and 6,
During movement of irradiated fuel assemblies.
What do you do on a loss of either offsite power source or an EDG per T.S. 3.8.2 AC Sources - Shutdown?
Loss of either offsite power source or EDG
IMMEDIATELY
Declare affected required feature(s) with no offsite power available inoperable.
OR
Suspend CORE ALTERATIONS.
AND
Suspend movement of irradiated fuel assemblies.
AND
Initiate action to suspend operations involving positive reactivity additions.
AND
Initiate action to restore required offsite power circuit/EDG to OPERABLE status.
Why is assuming a single failure and concurrent loss of all offsite or all onsite power is not required for T.S. 3.8.2 AC Sources - shutdown?
AC Sources Shutdown T.S. 3.8.2
The rationale for this is based on the fact that many Design
Basis Accidents (DBAs) that are analyzed above MODE 5 have no
specific analyses in MODES 5 and 6. Worst case bounding events are
deemed not credible in MODES 5 and 6 because the primary coolant
temperature and pressure, and the corresponding stresses result in the
probabilities of occurrence being significantly reduced, and in minimal
consequences.
Is SP Transformer 1-2 a qualified offsite source for T.S. 3.8.2 AC Sources - Shutdown?
T.S. 3.8.2 AC Sources - Shutdown
Since only one offsite AC source is required, independence is not a criterion.
Any of the three offsite supplies, Safeguards Transformer 1-1, Station Power Transformer 1-2, or Startup Transformer 1-2 is acceptable as a qualified circuit.
What is T.S. 3.8.3 Diesel Fuel, Lube Oil, and Starting Air?
3.8.3 Diesel Fuel, Lube Oil, and Starting Air
For each Diesel Generator (DG):
- The stored diesel fuel oil, lube oil, and starting air subsystem shall be within limits, and
- Both diesel fuel oil transfer systems shall be OPERABLE.
APPLICABILITY: When associated DG is required to be OPERABLE.
T.S. 3.8.3 Diesel Fuel, Lube Oil, and Starting Air requires how much fuel oil to consider the EDG’s operable?
T.S. 3.8.3 Diesel Fuel, Lube Oil, and Starting Air
If Fuel oil inventory less than a 7 day supply and greater than a 6 day supply, then you have 48 hours to restore inventory to within limits.
Less than a six day supply and both EDG’s are inoperable.
28,592 gallons is required for six days.
33,054 gallons is required for seven days.
T.S. 3.8.3 Diesel Fuel, Lube Oil, and Starting Air requires how much lube oil for EDG operability?
3.8.3 Diesel Fuel, Lube Oil, and Starting Air
If Stored lube oil inventory less than a 7 day supply and greater than a 6 day supply, then you have 48 hours to restore the inventory.
If less than a 6 day supply, both EDGs are inoperable.
A six day supply is 268 gallons
A seven day supply is 313 gallons
