Environmental Engineering Reference
In-Depth Information
term relates not to one system, but to several in-
teracting I&C systems, which together perform
all functions provided for RC&PS. Just in this
sense, the concept, the term that represents it and
abbreviation are used in this topic.
RC&PS (Figure 7) consists of individual I&C
systems:
• Warning of personnel about violations of
operational limits (normal and safe op-
eration) by neutron power and a period of
change.
• Monitoring of the system technical state
and diagnostics of failures of the system
and its components.
• Archiving of current values of reactivity,
neutron power, period of its change and
display of archival information.
• Neutron lux monitoring system (second
and third sets).
Emergency and preventive reactor protec-
tion system (irst and second sets).
Formation and output of messages about
values of monitored parameters and the
current system technical state for trans-
mission in IRMS and CIS through a local
network.
Reactor power control, unloading, limita-
tion and accelerated preventive protection
system.
Rod group and individual control system.
NFMS performs its functions in all reactor
operation modes: sub-critical, transient, station-
ary, emergency, including maximum design basis
accident and also during nuclear fuel reloading.
Significant peculiarity of NFMS is a wide range of
neutron flux density measurement, corresponding
to a change of relative neutron power from 10 %%
to 120% of nominal.
The RC&PS includes two independent NFMS
(first and second sets in Figure 7), operating
simultaneously and being interredundant. Each
NFMS monitors neuron flux during nuclear fuel
reloading, reactor start-up and power operation.
One more NFMS (third set in Figure 3), providing
a possibility to monitor and control the reactor
from ECR, is not contained in RC&PS.
The basis of each NFMS is formed by a
software-hardware complex, together with it pe-
ripheral equipment is supplied: sensors S (neutron
flux detection devices); warning means (visual
alarms); manual control means (set-points device,
mode switches); devices of archiving and display-
ing of values, of relative neutron power, period,
reactivity and set-points (built-in panel computers,
recordings on removable media device); device
of digital indication of neutron power and period
(digital indicator).
Real I&C systems, united by the concept
RC&PS, were developed by different organiza-
tions and / or on the basis of different equipment
families and modernized in different time, so each
of them can be considered individually.
Neutron Flux Monitoring
The main purposes of the neutron flux monitor-
ing system (NFMS) are: monitoring of reactor
relative neutron power and rate (period) of its
change; generation of discrete signals by speci-
fied conditions, which initiate actuation of the
emergency protection (rapid suppression of chain
reaction in the reactor), and preventive protection
(decrease of reactor power or prohibition on power
increase); generation analog signals, by which the
current value of relative neutron power (one of
the main regulated reactor facility parameters) is
determined.
In addition, NFMS performs:
• Calculation and display of reactivity.
• Display of current values of neutron power
and a period of its change.
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