Field Programmable Gate Array Technology for NPP I&Cs - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 134

In case condition (1) is not met, input and output
data of a development stage are not intertraceable
and stage results mist be corrected.
Traceability matrix includes four columns:

erands for each class and determination of
integral complexity metric value.
• Analysis of obtained complexity metric
values, formulation of conclusions and
recommendations.

1. Column of FPGA Algorithm Input
Components: Its elements are input com-
ponents А ij , i = 1,...,S, j = 1,...,L.
2. Column of FPGA Algorithm Output
Components: Its elements are output com-
ponents В ij , i = 1,...,S, j = 1,...,M.
3. Column of Traceability Results: Elements
are conclusions of traceability between
FPGA algorithm input and output compo-
nents; conclusion data take binary values
“meeting” (A ij ⇔ B ij met) or “not meeting”
(A ij ⇔ B ij not met).
4. Column of Comments: Additional data on
FPGA algorithm components development
and verification.

• Breaking into modules for those algo-

rithms where complexity metric exceeds
its limit value.

Key Advantages of
FPGA Technology

FPGA is a convenient technology not only for
implementation of auxiliary functions (trans-
formation and preliminary processing of data,
diagnostics, etc), it is also effective for imple-
mentation of safety important NPP I&Cs control
functions. Application of the FPGA technology
is more reasonable than application of software-
based technology (microprocessors) in many cases
(Kharchenko, V. S., 2008).
The application of FPGA technology has sig-
nificant advantages that can be utilized both in
I&C modernization projects of existing NPPs and
in I&C designs for new NPPs. These advantages
are the following:

Complexity Assessment: One of basic FPGA
electronic designs characteristics affecting their
reliability is complexity. FPGA electronic design
complexity metrics may be applied to access the
critical scope of signal formation algorithms and
integrated program model, above which the prob-
ability of bringing errors drastically increases.
Complexity assessment includes (McCabe, T.
A., 1976):

• Design, development, implementation, and
operation simplicity and transparency.
• Reduction of vulnerability of the digital
I&C system to cyber attacks or malicious
acts due to absence of any system software
or operating systems.
• Faster and more deterministic performance
due to capability of executing logic func-
tions and control algorithms in a parallel
mode.
• More reliable and error-free end-product
due to reduction in the complexity of the
veriication and validation (V&V) and im-
plementation processes.

• Analysis of problem oriented language in
which the algorithms have been developed,
separation of operator and operand classes.
• Prescription of weights from the point of
view of complexity for operator and oper-
and classes.
• Establishment of limit value for integral
complexity metric above which the prob-
ability of bringing errors into FPGA elec-
tronic designs drastically increases.
• Direct complexity measurement including
count of the number of operators and op-

• Relatively easy licensing process of FPGA-

based safety systems due to the simplicity
and transparency of system architecture