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 374

NP, 2000 plan and report on software verifica-
tion are submitted for approval to the regulatory
authority in a package of documents of technical
decision on assembling of the NPP I&C systems
(see below Stage 4).
At the final development stage design and
software documentation that defines composition
and structure of the SHC and contains required
data for its production, checking (control, testing)
and acceptance is released.
During validation compliance of the developed
SHC to requirements of guides and rules of nuclear
and radiation safety and RS is made. Validation
is performed by development organization and
manufacturer of the SHC according to the valida-
tion plan agreed with the regulatory authority. The
first stage of validation is preliminary off-line tests
of components and complex tests of the SHC with
simulators of signal sources and receivers. At the
second stage acceptance testing of the SHC, in
which designers, manufacturers, representatives
of prospective customers and regulatory authority
are participating, are performed. Validation results
reflected in a proper report, act and protocols of
preliminary and acceptance testing are submitted
for control to the regulatory authority. Positive
results of validation are the basis for shipping
the SHC to NPP.

• Requirement speciication for modiication
object agreed according to the established
procedure with the regulatory authority;
• Preliminary safety analysis report of modi-
ication project of NPP;
• Program and methods of preliminary test-
ing of modiication object (of-line and
complex within NPP);
• Quality assurance program of modiication;
• Software veriication plan and veriication
report;
• Results of the SHC validation (if the SHC
is modiied);
• Materials of algorithms' veriication which
were changed during modiication.

During the I&C system modification the fol-
lowing documents within safety analysis report or
in the form of separate documents are additionally
attached:

• Design assessment of I&C system

reliability;
• Analysis of system response to probable
failures in it;

• Stability analysis of control and regulation

loops (if any).

At this LC stage preliminary complex testing
of the system is performed at NPP for confirma-
tion that each of the functions specified in RS is
performed with the required quality and reliability.
Final approval of compliance of the I&C systems
to requirements of guides, rules, and standards on
nuclear and radiation safety and RS is performed
at further stages during trial operation and ac-
ceptance testing of the system.

Stage 4: Assembling and commissioning of I&C
systems at NPP.

At this stage, the operator develops a technical
decision on assembling of the modification object
including the following activities: disassembling
(if necessary) of old equipment, assembling of
new one, commissioning, preliminary (off-line
and complex within the NPP) testing of the
modification object.
To substantiate possibilities to carry out these
activities the operator attaches the following
documents to technical decision on assembling
of modification object:

Stage 5: Putting the I&C systems into trial opera-
tion at NPP.

According to Yastrebenetsky, 2012 all I&C
modernizations can be divided into pilot (modern-
izations implemented for the first time at NPP with