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Failure Mode and Effect Analysis of Cable Failures within a Fire PSA
(J. Herb and E. Piljugin)
An enhanced method for the assessment of cable failures caused by fire has been developed by GRS based on a
failure mode and effect analysis (FMEA). It intends to overcome the limitations of simplified screening methodologies.
Cable function
electrical power supply
(voltage level)
instrumentation cable
control cable
operational state
(open- or closed-circuit)
Fire PSA screening:
Selection of relevant compartments
Generic analysis of
potential cable failure
Cable type data
shielding
insulating material
construction
…
FMEA
(generic)
Detailed analyses for Fire PSA:
Analysis of the fire event trees and
the fire effects
U
Interruption of current flow,
conductor interruption
F
Fault to ground (short circuit
to ground inside or outside
of the cable)
Laying specifications
cable trays
vertical laying
cable layer (single, multiple)
…
Determination of failure
conditions in the
compartment
Determination of the first
(time) failure effect on the
cables in the compartment
Generic analysis of
cable failure modes
Identification of the relevant cable
failure modes inside the specified
compartment
Generic analysis of
cable failure effects
Analysis of the cable failure effects
on the connected components
Identification of the
cable in the specified
compartment
P
Hot short
(inside or outside of the cable)
Failure conditions (temperature)
experimental data
manufacturer‘s data
generic data
…
Identification of the
connected components
(electrical and I&C equipment)
Determination of the potential impact
on the required system functions
and/or the contribution to an
initiating event
Cable failure
U – interruption of current flow
F – short to ground
P – hot short
Generic analysis of
component failures
FMEA
(generic)
Input signal fault
consequence
Determination of the impact
of cable failures to
components and
PSA-system functions
Cable function
power supply
instrumentation cable
control cable
Output signal fault
consequence
Circuit data
continuous or alternating current
open or closed circuit (standby)
open or closed circuit (by demand)
Identification of alarm
messages
Common mode effects
(e.g. shut-down of an
I&C cabinet caused by
electrical protection)
Data of the connected component
required function on demand/standby
electrical protective functions/devices
fault alarm / fault monitoring
General arrangement drawing of the cabling
in the reference NPP
Interface to detailed analyses
for Fire PSA
The FMEA-tool CaFEA (Cable Failure Effect Analysis)
has been developed by GRS on the base of MS Access.
CaFEA supports the analysis and records the result of
the FMEA. The CaFEA-database contains
all relevant data on cables of the reference NPP
information on components (description, type,
operational mode etc.)
Main Control Room
Distribution Boards
I&C Cabinets
Measurement
DC circuits
Switchgear and Safeguard Building
I&C Cabinets
Reactor Protection System
e.g. LOGISTAT
I&C Cabinets
Limitation System
e.g. GEAMATIC
I&C Cabinets
Automatic Control
e.g. GEAMATIC
I&C Cabinets
Drive Control Level
e.g. GEAMATIC
control
check back
annucation
Distribution Boards
Plant Facility
Field Level
Power supply
Power supply
M
Reactor
Building
Switchgear
Facility
Based on information found in a generic FMEA for
representative components the cable specific FMEA can
be performed for each cable in all relevant compartments
of a NPP. The availability of the cable data in a database
provides an opportunity for further investigations such
as the analysis of failure propagation due to cable routing
via crossbar racks/distribution boards.
Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH
Forschungsinstitute, 85748 Garching
+49(0)89-32004-418 / [email protected]
+49(0)89-32004-470 / [email protected]
0810601
I&C Cabinets
Limit value monitor
DC circuits
Grafik
I&C Rooms
Power supply
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