Diversity and Multi-Version Systems - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 185

A LAW “NEGATION OF NEGATION”:
STAGES OF DIVERSITY
APPROACH IMPLEMENTATION
EVOLUTION IN NPP I&CS

ry subsystem and software (MP)-based
secondary subsystem; it was the irst
“negation;”

• Stage 2 (1990s): Use of primary and sec-

ondary subsystems with software (SW)
diversity (I&C platforms produced by
Siemens, WH and other companies); ex-
ample of multi-version systems with
software diversity is two-version system
consisting of subsystems developed using
microprocessors Intel and Motorola (lan-
guages C and Ada); it completed the irst
cycle of “negation of negation;”

Interesting are the results of transformation of
multi-version I&Cs for the last decades in context
of hardware-software-FPGA technologies devel-
opment. There are a few diversity implementation
evolution stages in safety-critical NPP I&Cs, in
particular, reactor trip systems. Analysis of these
stages allows formulating (or demonstrating truth)
a law “negation of negation” (Kharchenko et al.,
2009) (Figure 1): • Stage 3 (2000s, irst half): Transition to

FPGA-based primary and software-based
secondary subsystems with equipment,
design and software diversity (irst gen-
eration of the I&C platforms produced by
RPC Radiy); it was next “negation;”

• Stage 1 (1970-1980s): Use of hardware

(hard logic, HL)-based one-version sys-
tems and transition from hardware (HW)-
based systems with identical subsystems to
systems with hardware (HL)-based prima- • Stage 4 (2000s, second half): Application

of FPGA-oriented soft processors for a pri-
mary subsystem and FPGA project devel-
oped using HDL-oriented language (hard
logic) for creation of a secondary subsys-
tem (next generation of the I&C platform
produced by RPC Radiy); it completed the
second cycle of “negation of negation;”

Figure 1. Stages of diversity approach implementa-
tion evolution in safety-critical NPP I&Cs

• Stage 5 (beginning of 2010s): Application

of diferent FPGAs (hard logic) produced
by diferent manufacturers (and other types
of diversity) for primary and secondary
subsystems correspondingly; it is next
“negation.”

What will be the next step? Probably, advance-
ment of electronic technologies, in particular,
nanotechnologies, naturally dependable, safe and
secure chips will create new perspectives and
possibilities for development of diversity-oriented
decisions. Actel, Altera and other companies in-
form about creating first chips called nano FPGAs
allowing to develop fault-tolerant projects using
large-scale means.