Environmental Engineering Reference
In-Depth Information
drawbacks and benefits connected with the use
of the diversity.
The standards are not enough detailed to make
all necessary decisions concerning the diversity.
It's important to develop additional detailed tech-
niques of assessing diversity and choosing optimal
kinds and volume of the diversity according to
criterion “safety-reliability-cost.”
FPGA technology. Hence, they stipulate necessity
to analyze and decrease such risks, to use positive
features of new technologies.
Uniqueness of Multi-
Version Systems
There are a lot of DA implementations in critical
domains (Kharchenko et al., 2011) but:
NEW CHALLENGES OF
DIVERSITY IMPLEMENTATION
IN NPP I & C SYSTEM
• MVS component failures occur rarely; it
does not allow to use statistical methods to
evaluate reliability indicators.
•
Comparative analysis of failures for difer-
ent applications is not enough.
Technology and Risks
Modern software/microprocessor (MP)-based
and hardware/mixed FPGA-based technologies
ensure new possibilities for implementation of the
diversity approach (DA), because their application
allows to use two additional kinds of the diversity:
It concerns both MP-based and FPGA-based
MVSs, but MP-based NPP I&C systems are op-
erated more than forty years, when FPGA-based
are operated during last ten-twelve years and are
more unique.
Key questions are:
•
FPGA vs MP (main system is developed
using FPGAs, diverse system is developed
using MPs).
• How we should collect, compare experi-
ence of diferent domains and take into
consideration features of DA applications?
•
FPGA1 vs FPGA2 (diferent manufactur-
ers Altera, Xilinx, Actel (Microsemi), etc.,
subtechnologies SRAM, Flash, Antifuse,
development techniques are used to devel-
op main and diverse systems) (Kharchenko
et al., 2011; Kharchenko et al., 2008).
•
Is long time of non-failure operation reli-
able proof?
Standards Related to D3 Principle
A lot of standards and technical reports contain
requirements to diversity and recommendations
regarding to assessment of MVSs: IEC and IAEA
standards (IEC 61513: 2001, IEC 60880: 2006,
IAEA NS-G-1.3: 2002, etc), IEEE standards and
NUREG guides (IEEE std.7-4.3.2:1993, NUREG/
CR-6303:1994, NUREG/CR-7007:2009, etc.),
EPRI reports (EPRI 1019183:2009, EPRI
1019181:2009, EPRI 1019182:2009), some na-
tional guides, for example (NP 306.5.02/3.035:
2000).
The technologies of FPGA projects develop-
ment, in particular graphical scheme and library
blocks in CAD environment, special hardware
describing languages (VHDL, Verilog, Java
HDL, etc), microprocessor emulators, which
are implemented as IP-cores allow increasing a
number of possible options of different project
versions and multi-version I&Cs. But they can
create additional risks and deficits of safety or
transform pre-existed ones caused by features of
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