atw 2018-02

inforum

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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