Organization and Information Support of Expert Reviews of I&C Systems Modernization at NPP of Ukraine - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 372

• Possibility and suitability of preservation
of individual elements of the modiied
object, taking into account their technical
condition and compliance with require-
ments of standards and rules of NRS;
• Other (besides efects on safety) expect-
ed technical and economic modiication
results;
• A list of participants of modiication (de-
signers, suppliers of equipment and ser-
vices, software designers etc.);

• A variation range and limits of probable
values of controlled parameters;
• Dependencies between inputs and outputs
of each function speciied in a form of
verbal descriptions, formulas, tables, and
algorithms;

• Requirements on accuracy, time character-

istics, dependability (reliability and main-
tainability) of each of basic functions;

• Signals, interfaces and protocols of data

communication with other instrumentation
and control systems. • Results of operation of similar modiication

objects on other NPPs (if it is possible);

• Time schedule to implement modiication

with determination of required modes of
tests.

Expected conditions in the estimated places
of equipment installation are also specified: op-
erating and limit values of influencing factors of
environment and specific environments (if any),
mechanical and electrical influences, character-
istics of electromagnetic environment, possible
long- and short-term deviations of power sup-
ply parameters, within which equipment should
perform its functions with required quality and
reliability.
Initial data determined by the customer and
requirements to the system are concretized and
supplemented in requirement specification (RS)
for creation or modernization of the I&C systems.
Requirement Specification:

If necessary, after consideration of concep-
tual technical decisions the regulatory authority
develops a plan of safety assessment of modifi-
cation project, in which LC stages of NPP I&C
systems, documents released at each stage and
expert reviews (see below) of these documents
are provided.

Stage 2: Development of technical specifications
for creation (modernization) of the NPP
I&C systems.

Initial data and requirements on system are
specified by the customer (operator) taking into
account the I&C system purpose, its connections
with other systems, peculiarities of operating
personnel work, results of analysis of power unit
safety. These requirements should not depend on
possible ways of system implementation. For a
new or modernized system initial data and require-
ments define at least:

• Deines the system structure and distribu-
tion of functions among its components
(subsystems);
• Regulates initial data and requirements
on components (hardware, software and
software-hardware complex (SHC)) that
should be developed for the system (de-
tail deinition of term “software-hardware
complex” is given in Chapter 1);
• Deines a list of earlier developed (“ready”)
components, which are supposed to be used
in the system, determines requirements
on such components and also a necessity,
volume and ways of checking compliance
with these requirements (qualiication).

• Purpose, main and additional functions

and their role in safety assurance;

• Lists of controlled parameters, events and

states;