ELECTRICAL SYSTEMS
AP1000 Technology
Chapter 9.0 11
Objective 1
State the purpose of the following:
a. Onsite standby diesel generators
b. Ancillary ac diesel generators
c. Class 1E 250 Vdc distribution system
d. Class 1E uninterruptible power supplies
(UPS)
e. Non-
Non-Class 1E dc and UPS system
2
Objective 2
Describe the major differences between the
AP1000 and current operating Westinghouse
plants onsite electrical system designs.
3
Onsite Power Systems
Non
Non--Class 1E main ac power system
The dc power system consists of two
independent systems:
Class 1E dc system
s stem and
non
non--Class 1E dc system
4
Onsite AC Power System
Non
Non--Class 1E comprised of normal, preferred,
maintenance, and standby power supplies.
Normal: TG supplies plant power during normal
power operation.
Preferred: Shutdown power normally provided
via the switchyard.
Maintenance: Site specific through reserve
auxiliary transformers (backup to preferred
supply)
5
Maintenance
Preferred
Normal
Condensate pump A Aux. boiler Condensate pump B
Ci c water
Circ. ate pump
p mp A Circ water pump B
Circ.
MFW pump A MFW pump B
Fig. 9-2 (Sheet 1)
The plant is designed to sustain a load rejection from 100 percent power with the
turbine generator continuing stable operation while supplying the plant house loads.
6
MAINTENANCE MAINTENANCE
Fig. 9-2 (Sheet 2)
NORMAL or PREFERRED NORMAL or PREFERRED
Class 1E circuit breakers used for
the specific purpose of satisfying
the safety-related tripping
requirement of these pumps.
7
Fig. 9-2 (Sheet 3)
Non-Class 1E DGs
Standby
Water chiller A Water chiller B
SUFW pump A SUFW pump B
MU pump A MU pump B
CCS pump A CCS pump B
SWS pump A SWS pump B
Raw water pump A Raw water pump B
Supplies system components that
enhance an orderly plant shutdown
under emergency conditions
(priority loads for defense-in-depth
functions).
8
Ancillary AC Diesel Generators
Provide backup power for:
¾ Post-accident monitoring loads, MCR lighting, and
Post-
MCR ventilation.
¾ PCS recirculation p
pumpp to refill the PCS water
storage tank and the spent fuel pool.
¾ Local loads to support operation of the ancillary
generator (lighting and fuel tank heating).
9
Fig. 9-3
The ancillary generators are not needed for the first 72 hours following a loss of all
other ac sources.
10
Non--Class 1E DC & UPS System
Non
Provides dc and uninterruptible ac power to
plant non-
non-Class 1E loads:
that are critical for plant operation,
investment protection, and
y g igniters
hydrogen g located inside containment.
The onsite standby DG-
DG-backed 480 Vac
distribution system provides the normal ac
power to the battery chargers.
The batteries are sized to supply the system
loads for two hours after loss of all ac power.
11
Fig. 9-5 (Sheet 1)
12
Fig. 9-5 (Sheet 2)
13
Class 1E DC & UPS System
24
24--hour battery banks (4), provide power for
loads required for the first 24 hours following a
loss of all ac power concurrent with a DBA.
72
72--hour battery banks (2), is used for loads
required
q for 72 hours followingg the same event.
Spare battery bank with charger is provided for
the Class 1E dc and UPS system.
Class 1E UPS provides 120 Vac to four
independent divisions of Class 1E I&C power
buses.
14
Fig. 9-4 (Sheet 1)
15
Fig. 9-4 (Sheet 2)
16
Fig. 9-4 (Sheet 3)
17
Fig. 9-4 (Sheet 4)
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Questions?
19
Which of the following are Class 1E components of the
AP1000 plant electrical systems?
a. 2-hour battery banks
b. 72
72--hour battery banks
c. Standby AC diesel generators
d. Ancillary AC diesel generators
20
The ancillary DGs are not needed for the first ______
hours following a loss of all other ac sources.
a. 2
b. 24
c. 48
d. 72
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