Environmental Engineering Reference
In-Depth Information
Rate of data transfer over the local Westnet
II network -- 16,000 parameters per sec-
ond, etc.
ing factors of the environment are determined
according to (NP, 2000,b) depending on the
operating condition group.
A comparison of these values with the require-
ments reveal that under the operating conditions in
which upper and lower level stations are arranged,
the external influences cannot influence their fit-
ness for work and technical characteristics. How-
ever, compensatory measures were taken so that
the limiting values of temperature and humidity
in this space would not exceed acceptable limits
for workstations.
The SPDS, as a system of safety class 3, is
assigned to the category of seismic stability II
and should fulfill the stipulated functions to the
assigned extent with characteristics regulated in
the specifications after action of vibration and
mechanical shocks, which are caused by a design
earthquake at the NPP site. For example, the in-
tensity of a design earthquake for the site of the
South-Ukrainian NPP is determined to be a grade
of 6. Considerably more rigid requirements for
seismic stability of the DPU have been established
in the specification - grade of 8 for installation
at level up to 10 meters. The conformity to these
requirements is confirmed by test materials sub-
mitted by Westinghouse. For commercial items
(workstations, video monitors, peripheral equip-
ment and so forth), which are used as part of the
upper level stations, additional reinforcement of
items installed on work surfaces of table sand ped-
estals was stipulated as a compensatory measure.
Electromagnetic compatibility calls for stabil-
ity of all component parts of the SPDS with respect
to the action of interference from the power grid,
special grounding loop, along the transmission
circuits of signals, communication lines, local
networks, and also in the space of the premises.
Stability requirements with respect to the
following kinds of interference have been estab-
lished in the specifications: discharges of static
electricity to the frame, control members and
external shields of cables; microsecond impulse
interference in power circuits; nanosecond pulse
In order to display information at workstations
of operating personnel, color video monitors are
used with diagonal screen of 20 inches and 27
inches, resolution capacity of 1152 x 900 dots,
number of colors 256. For the input, display and
recording of data one uses conventional designa-
tions (including abbreviations and acronyms),
which are convenient and understood by personnel
and do not require additional deciphering.
Stability of Functions
Requirements for stability of functions include:
Requirements for resistance to external
inluences;
Requirements for electromagnetic compat-
ibility (noise tolerance);
Requirements for protection from unau-
thorized access, etc.
The stability of functions was evaluated on the
basis of requirements of regulatory documents for
nuclear safety, which were in effect in Ukraine at
the time of SPDS introduction.
Resistance to external influences assures ful-
fillment of the stipulated functions (to the assigned
extent and with regulated characteristics) under
SPDS operating conditions and with disturbances
of working conditions caused by: failures of sup-
porting systems, which ensure operating working
conditions; disturbances of operating mode of
powerful electric engineering units; anomalous
natural phenomena (e.g., earthquakes).
External influencing factors of the environment
are characterized by working values and limiting
values, which can occur in a limited amount of
time, for example during failures of ventilation,
air conditioning systems and so forth. Generalized
working and limiting values of external influenc-
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