Standby power supplies

Dedicated water tanks, (ground level and overhead tanks), standby power supply through DG set, and public address system must be available. 

Requirement of FFS system storage of water (ground level/overhead tanks), standby power supply DG set, public address system, smoke detectors, sprinklers must be provided and inspected regularly. 

The main plant components (vessels, reactor installation, turbine generator plant, control consoles and systems, electric system, auxiliary and standby power supplies) are mounted, tested and commissioned at an interior shipyard. 

In the UK, UPS Systems has installed a standby power supply system using three PEM cells from Hydrogenics at its Hungerford headquarters. These rackmounted units are able to supply a three phase 10 kW mains power supply. 

USNRC Regulatory Guide 1.9, "Standby power supplies. ... 

The onsite ac power system (ECS) is a non-class IE system comprised of a normal, preferred, maintenance and standby power supplies. The normal, preferred, and maintenance power supplies are included in the main ac power system. The standby power is included in the onsite standby power system. 

Section 10.8 summarises the requirements for standby power supplies for safety and emergency services, grouped depending on the required changeover time. This means that consideration needs to be given to the provision of uninterruptable supplies in some circumstances, and stand-by supplies in others. 

The standby power supply system (level C) supplies those components indispensable for nuclear safety but only needed after a delay which allows corrective measures to be implemented. In case of a LOSSP 3 diesel generators, one for each division, ensure power supply after at most 32 h. The diesel generators can also feed into the spare power supply system. 

Batteries have many advantages over other power sources, as outlined in Table 6.1 They are efficient, convenient, and reliable, need little maintenance, and can be easily configured to user requirements. As a result, batteries are used in an extremely wide range and variety of sizes and applications—from as small as 3 mAh for watches and memory backup to as large as 20,000 Ah for submarine and standby power supplies. 

It can also identify potential problems with dependent failures which might affect several apparently separate redundant equipments (e.g. both the duty and standby power supplies). Allocates budgets to lower level events. 

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