IEC 63046-2020 pdf free download

IEC 63046-2020 pdf free download.Nuclear power plants — Electrical power system — General requirements
Centrales nucléaires de puissance — Système d’alimentation électrique — Exigences generales.
• failure modes and the potential for common cause failure of programmable digital items. The consequences of CCF caused by programmable digital items should be assessed.
Consideration shall be given to diversity in the electrical system design to reduce the system vulnerability to CCF from programmable digital items.
Particular attention should be taken where there are proposals to network electrical protection systems through programmable protection relays with two way communication from central control systems.
These systems present a significant risk of common cause failure and should be avoided wherever possible for NPPs.
Where a networked system with two way communication is implemented then comprehensive validation and verification of the programmable devices should be undertaken to demonstrate the mitigations against potential CCF that the risk of CCF due to software error or cyber attack is acceptable in accordance with overall facility safety case.
Where programmable digital items are installed in the electrical system design their implementation shall be validated based on their safety classification.
This validation shall follow the procedures defined in IEC 62671.
System cyber security vulnerabilities and consequence associated with the Electrical Power System should be assessed where programmable digital items are implemented.
Justification of a programmable digital items should be based on the assessment of safety function(s)/failure modes.
Programmable digital items in electrical systems should be considered in the context of the overall electrical design and safety case.
Implementation of programmable digital items in electrical power systems requires a multidisciplinary involvement.
7.2.4 Provisions for coping with Loss Of Off-site Power
The design should include provisions to detect this condition in order to initiate appropriate automatic or manual actions.
The following design measures to cope with a Loss Of Off-site Power should be considered (following the functional requirements applicable to the EPS and based on the electrical need of the supported loads):
• provision of adequate battery capacity to supply power to safety classified instrumentation and control equipment, and other vital equipment required in design basis conditions;
• installing standby AC power sources which fulfil the independence requirements between divisions (refer to 7.2.3.3.2);
• design the NPP with passive safety features.
The power balance, restoration time and the mission time of the systems supplied during a LOOP condition should be provided as input data to select the adequate solutions.IEC 63046-2020 pdf free download.