1 Scope
IEC 62855
provides the electrotechnical engineering guidelines for analysis of AC and DC electrical
power systems in nuclear power plants (NPPs) in order to demonstrate that the power
sources and the distribution systems have the capability for safe operation and shut
down of the NPP, bringing it to a controlled state after an anticipated operational
occurrence or accident conditions and finally reaching a safe state.
The analytical studies discussed in this document provide assurance that the design
bases are satisfied to meet their functional requirements under the conditions produced
by the applicable design basis events. The studies provide assurance that the electrical
power system is capable of supporting safety functions during all required plant conditions.
Analytical studies validate the robustness and adequacy of design margins and demonstrate
the capability of electrical power systems to support plant operation for normal,
abnormal, degraded and accident conditions.
NOTE The safety functions are described in IAEA Specific Safety Requirements SSR-2/1 related
to the design of the nuclear power plants..
The analyses are used to verify that the electrical power system can withstand minor
disturbances and that the consequences of major disturbances or failures do not degrade
the capability of the electrical power systems to support safe shutdown of the plant
and maintain the plant in shutdown condition.
The analyses are performed with one or more of
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