Software of Safety Important I&C Systems - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 163

while carrying out expert evaluations under
conditions of limited time and resources the
main efforts must be concentrated in critical
steps and results of software development,
analysis of the completeness and reliability
of tests.

supplemented by defining recommendations for
additional testing of the functions more important
for safety, transmission of comments and additions
to the developer and obtaining a corrected and
supplemented verification plan from him.
In the stage of software verification report
preparation the evaluation contains six steps:
evaluation of the existence in the verification re-
port of protocols and official statements for each
program and method of testing; evaluation of the
completeness of the tests carried out; evaluation
of independence of the verification conducted;
evaluation of the software tools used in the de-
velopment and verification; evaluation of the rate
of success of completion of all tests; statement of
recommendations for the regulatory body on the
possibility of using the software.
The stages of evaluating the plan and the report
on software verification are the most important.
At these stages the regulatory body has the op-
portunity to receive evidence of achievement of
the required level of quality and reliability of the
software. For this purpose the plans, programs and
methods of software testing are evaluated before
the beginning of the tests, and the additions and
comments made are transmitted to the software
developer for their consideration.

Next we will propose the content of operations
for software evaluation at all basic stages of the
lifecycle: development of requirements for soft-
ware, design and coding of software, verification
(development of the verification plan, preparation
of the verification report).
In the stage of software requirements develop-
ment the evaluation contains three steps: evalua-
tion of the conformity of requirements for software
to the requirements for the system; evaluation of the
representation and specifications of requirements
for software and general requirements; transfer of
findings to the developer and obtaining back the
corrective and additional requirements.
At the software design stage the evaluation
contains four steps: evaluation of implementation
of software requirements in the design; analysis
of the structure for a subject of assured protection
from common cause failures due to software errors;
listing of requirements and functions of software
for use in subsequent stages of the evaluation;
transfer of findings to the developer and obtaining
from him information and corrective actions for
software design and evaluation of their adequacy.
At the stage of software verification plan
development the evaluation contains four steps:
evaluation of the existence in the verification
plan of programs and methods for software test-
ing; evaluation of accessibility of the verification
plan; evaluation of reflection in the verification
plan the requirements from the detailed list,
which is compiled in the preceding stage of the
evaluation; evaluation of the completeness and
adequacy of the number of tests included in the
verification plan. If necessary these stages can be

Evaluation of Software Characteristic

Tasks and approaches to evaluation: Evaluation
of the software characteristics includes the fol-
lowing tasks.
The first task is analysis of software conformity
to general requirements defined in national and
international standards. These requirements do not
depend directly on the functional purpose of the
software, but are determined by the designation
and safety classification of systems.
The second task is evaluation of the complete-
ness and quality of implementation of functional
requirements in the software, which are defined