atw Vol. 63 (2018) | Issue 2 ı February
OPERATION AND NEW BUILD 98
Drawing
No.
including (1) loss-of-coolant accidents
(LOCA), (2) main steam line
breaks (MSLB), (3) steam generator
tube ruptures (SGTR), or (4)
control rod ejection accidents
(REA.)
5. Any wires or equipment in the area
of a fire that are not protected by
fire wrap are burned, unless the
results fire disaster analysis prove
otherwise.
6. Fire-induced wire/circuit damage
can lead to open circuits, short
circuits, hot shorts, and shorts to
ground.
7. The valves, pipelines, tanks, or
incombustible instrument wires
affected by the fire do not cause
damage to the pressure boundary.
8. Despite fire damage to instruments,
the pressure boundaries
of fluids within them are not
damaged.
9. Motor-operated valves do not malfunction
due to fire damage to
power wires, but they may malfunction
following fire damage to
control circuits.
10. During post-fire safe shutdown,
power units may be controlled
manually using existing equipment,
as long as the fire does not
directly hinder such operations.
The scope of the core knowledge
relating to post-fire safe shutdown
capacity can be clearly defined and
verified based on the analytical
methods proposed in NEI 00-01 Rev. 2
and the target performance of safe
shutdown capacity.
Step 4: Establish inventory of
post-fire safe shutdown equipment.
Determine the specifications of
post-fire safe shutdown equipment
(Table 2): 1. attributes, 2. operating
status, and 3. path parameters [NFPA,
2001].
Function Description
Old System
Code
SSD
Code
1 RCS BB B1/B2
2 RCS-ACCUM ISO BH B1/B2
3 CVCS HHSI BG B5/B6
4 CVCS HHSI SUP BG BS56
5 SIS HHSI BH B7/B8
6 CVCS RCP BG C5/C6
| | Tab. 2.
Post-fire safe shutdown system parameters for case study.
Phase 2: Identify wire/circuits
associated with post-fire alarm safe
shutdown.
Step 1: Identify wires and circuits
associated used with post-fire safe
shutdown equipment.
Using the original design data of
the plant, list every power wire and
control wire associated with the
post-fire safe shutdown equipment.
Step 2: Determine the specifications
of all wire/circuits associated
with post-fire safe shutdown. Set the
parameters of operating status,
equipment attributes, and the safe
shutdown paths to which they belong.
Step 3: Refer to the existing database,
control wiring diagram (CWD),
and control logic diagram (CLD) to
identify the control wires associated
with each piece of equipment.
Step 4: Compile an inventory of
wires associated with post-fire safe
shutdown (NEI, 2009).
A series post-fire safe shutdown
path (Code: HSD-P1):
(A1+A3)+(B1+B3+B5+B7+B9)+
(D1+E1+F1+G1+H1+I1+J1+K1+
L1+M1+N1+P1+S1+U1+V1+
W1+X1+Y1.)
B series post-fire safe shutdown
path (Code: HSD-P2):
(A2+A4)+(B2+B4+B6+B8+B10)+
(D2+E2+F2+G2+H2+I2+J2+K2+
L2+M2+N2+P2+S2+U2+V2+
W2+X2+Y2)
Taking the plant from operating
to hot shutdown requires that the
equipment listed above be operational.
These devices must also be
included in independent paths
HSD-P2 or HSD-P1.
Example of system parameters
(Table 2) and shutdown path: The
power for the motor driven auxiliary
feed water pump (A-1M-AL-P017) in
auxiliary feed water system of Series A
(system parameter B3) is supplied by
Class 1E 4.16kV Bus A-1E-PB-S01 (PB
system). In post-fire safe shutdown
operation mode, this bus is powered
by the emergency diesel generator in
Series A (system parameter D1). Thus,
a supply of lubricating oil and a fuel
(KJ system) must be available for the
emergency diesel generator. At the
same time, it is essential that the 125V
DC electrical system (PK system)
provide power to the control panel
of the emergency diesel generator
A-1J-ZD-P001. The emergency diesel
generator is uses a jacket water-cooler
A-1M-KJ-X072 running off of a
seawater system (EF system); the
power for the seawater pump A-1M-
EF-P103, P104 is provided by the
4.16kV bus A-1E-PB-S01 (PB system.)
This is an example of the analysis used
to establish the interdependence of
systems within a given post-fire safe
shutdown path.
Phase 3: Establish an inventory of
wire/circuits associated with post-fire
safe shutdown.
Step 1: Use the wire/circuit inventory
established in previous phase to
conduct effect analysis of fire-induced
wire/circuit failures. Analyze fire- induced
circuit failures (power, control,
instrument) associated with each piece
of equipment, based on inventory of
equipment used in post-fire safe shutdown.
These wire/circuits can be
divided into two categories: those
necessary to post-fire hot shutdown
and those necessary to post-fire safe
shutdown. Single-line diagrams, CLDs,
and CWDs of post-fire safe shutdown
equipment in the original design are
used to investigate fire-induced circuit
failures, as follows:
(1) Categorization of wires required
for post-fire hot shutdown:
a. Power and control wires required
for manual operation of equipment
used in post-fire hot shutdowns
b. Power and signal wires for instruments
used in process monitoring
during post-fire hot shutdown
c. Wires that could cause the malfunction
(through fire-induced
circuit failure) of equipment required
for post-fire hot shutdowns
d. Wires that could cause the malfunction
of components (through
fire-induced circuit failure) in
high/low pressure system
(2) Categorization of wires required
for post-fire safe shutdown:
a. Power and control wires required
for manual operation of equipment
used in post-fire cold shutdowns
b. Wires that could cause the malfunction
(through fire-induced
circuit failure) of equipment required
for cold shutdowns
c. Wires that could cause the malfunction
of components crucial to
shutdowns (through fire-induced
circuit failure)
Fire-induced circuit-failure parameters
were established as follows:
1) fire-induced circuit-failure equipment,
2) operating status parameters,
3) fire-induced circuit-failure parameters,
and 4) wire/circuit attribute
parameters.
Step 2: Use the circuit-failure
parameters to construct a table for the
analysis of circuits used in post-fire
safe shutdown.
Effect analysis of fire-induced
circuit failures associated with the
post-fire safe shutdown equipment,
including open circuits, short circuits,
hot shorts, and shorts to ground (445
items in total). This analysis produced
5,149 results.
Operation and New Build
The Application of Knowledge Management and TRIZ for solving the Safe Shutdown Capability in Case of Fire Alarms in Nuclear Power Plants ı Chia-Nan Wang, Hsin-Po Chen, Ming-Hsien Hsueh and Fong-Li Chin
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