Properties of Safety Important I&C Systems and their Components - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 87

• For SHC and peripheral equipment, com-

posed of several operating stand-alone
component parts, are usually put to the test
inluences individually.

During checking of resistance to EIF of the
environment, one is guided by test data about
actual working values of these EIF in places of
devices' location, estimation results of their lim-
iting values, expected duration and frequency of
their occurrence. In case of lack of such data one
considers generalized working (Table 2) and
limit (Table 3 and 4) values for relevant groups
of operation conditions (sign “−” means that EIF
values are not regulated).
Resistance to EIF of the environment is con-
firmed by results of tests for influences of tem-
perature, humidity, barometric pressure, ionizing
radiation. Degree of test hardness is determined
for EIF of each type, considering a group of op-
eration conditions, to which a tested device relates,
on the basis of Table 5.
Parameters of test influences, simulating EIF
of environment are defined on the basis of a degree
of test hardness using Table 6.
Resistance to influence of absorbed dose rate
and to absorbed rate of continuous low intensive
ionizing γ-radiation is checked by an experimen-
tal method and / or analysis of reference informa-
tion, defining resistance of applied materials and
component parts. Resistance to impacts of cor-
rosive agents and dust are not executes if it is
guaranteed by the design, applied materials and
component parts and also experience of analogue
operation at NPPs of Ukraine.

• Checking is executed in each of the regu-

lated operation modes (or in a mode, in a
which an product is the most EIF sensitive
of a particular type, provide it was prelimi-
nary speciied).

• Test inluence is repeated a required num-

ber of times within a suicient time period
to estimate operation correctness with a re-
quired validation.

Resistance to the
Environment Influence

SHC and peripheral equipment are resistant to
the expected working values of EIF environment
(without time restrictions) and to limiting values
of these EIF (within an expected maximal duration
of their existence). Working and limiting values
of EIF environment is determined by a group of
operating conditions, containing in a peripheral
equipment and SHC (Table 1).

Table 1. Groups of operating conditions

Location
Area

Room Category Group of

Operation
Conditions

Resistance to Mechanical Influences

SHC and peripheral equipment are resistant to ex-
pected working values of mechanical EIF (without
a time restriction) and to limiting values of these
EIF, occurred during earthquakes. Working values
of mechanical EIF are determined by a group of
location conditions, to which each operating stand-
alone device, contained in peripheral equipment
and SHC, is related (Table 7).
During checking of resistance to working
values of mechanical EIF, one is guided by test
data about actual values of these EIF in places of

Strict
access area

Rooms inside containment Е.1.1

Rooms of technological
equipment

Е.1.2

Rooms of primary transducers Е.1.3

Rooms of electrical equipment
and SHC

Е.1.4

Normal
access area

Rooms of technological
equipment

Е.2.1

Rooms of electrical equipment
and SHC

Е.2.2

Rooms with air condition (MCR,
ECR, etc.)

Е.2.3