Emergency Electrical Power Sources

Structures, systems and components important to safety vhich are installed as redundant items, or are called upon when normal operating conditions are threatened or lost, are normally kept in standby or off-line states. Examples of such SSCs are reactor containment vessels, emergency electric power sources, isolation valves and safety valves. Some of these SSCs cannot be monitored in situ for their operating reliability. Testing and surveillance for the actual conditions under which they are expected to operate, and which are generally difficult or impossible to reproduce, are usually undertaken under simulated conditions. These simulated conditions should be carefully planned, and the results should be interpreted prudently. 

The starboard side pontoon carries the auxiliary equipment such as standby and emergency electric power sources and pumps. 

As of December 1999, installed capacity consists of 6.7% hydro, 26.3% coal, 10.0% oil, 26.3% gas and 29.2% nuclear. The emergence of LNG as one of the major electric power sources in Korea implies that the portfolio of energy sources will depend not only on the cost of power generation but also on the public preference for environment protection and the manageability of power supply. 

Most HWRs have two sources of emergency electrical power Group 1 Class III diesels and separate, independent, seismically qualified Group 2 Class III diesels. This greatly reduces the risk of station blackout. 

Requirements for the availability of the electrical power sources should be stated for all operational states. These include off-site sources on-site generators (diesels and gas turbines, including associated fuel reserves) batteries and associated control protective, distribution and switching devices. The operability requirements should be such that sufficient power will be available to supply all safety related equipment necessary for safe shutdown of the plant, and for the mitigation and control of accident conditions. The operabihty requirements should determine the necessary power, redundancy of supply lines, maximum permissible time delays and necessary duration of the emergency power supply. Equivalent requirements should be stated for other power sources (for example, the pneumatic power system). Particular care should be taken to ensure that electrical supplies remain adequate in shutdown operations, when many systems and components will be out of service for maintenance. 

An obvious example is the situation which can occur such that a loss of offsite power makes some power buses unavailable for RCS heat removal. In addition, this loss-of-power mitiator affects the availability of the remaining systems, because emergency power becomes the only source of electric power. 

Focusing on the concept of the completely sealed system, the Sanyo Electric Co. developed sealed-type nickel-cadmium batteries in 1961. This type of battery enjoys a wide application range that is still expanding a large variety of nickel-cadmium batteries has been developed to meet user needs ranging from low-current uses like emergency power sources and semiconductor memories to high-power applications such as cordless drills. 

The main fields of application for this battery chemistry include portable TVs, radio receivers, lamps, flashlights, electric shavers, barrier lightning, instruments, batteries for portable rechargers, emergency power supplies, small refrigerators, power sources for tourists, hunters, geologists, shepherds and so on. Parameters of some batteries, assembled from the modules, are summarized in Table 4. 

Both scrubbers will be supplied with three sources of electrical power - the main grid supply, a back-up grid supply from a different substation and an emergency diesel generator. In the emergency chlorine scrubber, critical equipment items will be backed-up by automatic start-up of stand-by equipment. A gravity head tank of caustic soda and a nitrogen ejector will also be provided to allow safe neutralisation of chlorine vents in the event of total power failure. 

Electric power should be available from two highly reliable sources. The usual arrangement is an alternating current (AC) power supply, with trickle charger supplying an emergency battery system. Batteries should be sized for loss of primary power for a period of no less than 8 hours, and for at least 12 hours if the supply is not reasonably reliable. An exception is power for alarm bells or horns, which require only 1 hour of emergency power. The power supply should be monitored by a power-on lamp on the control panel and a main power failure alarm. 

As the book has been written for the non-specialist, the theoretical background to the basic processes involved in cell operation is described in some detail in preference to a more thorough series of comparisons of the characteristics and performance of competing systems. We have excluded any discussion on the very closely related field of fuel cells since a number of accounts of this topic have been published recently. It has been our intention to describe and characterize most of the established and emerging primary and secondary battery systems which are of current commercial or theoretical interest. Research into novel power sources may shortly lead to the major breakthroughs necessary before electric vehicles become a major component of the transportation system, and... 

The latter batteries are used for such different applications as in consumer elee-tronics, in vehicles for starting, lighting, and ignition (SLI) and for traction, as emergency power supplies, in load-leveling systems of electric power stations to supply peak demand, and as systems to couple with alternative energy sources. 

A pharmaceutical plant can obtain emergency or standby electrical power from generators, rechargeable batteries, and in rare cases from a separate utility service. Uninterruptible power supplies, central storage battery system, and unit equipment all use rechargeable batteries for their emergency source of power. 

In addition to the normal temperature control provided by refrigeration and heating systems, separate temperature alarms should be considered. Both low and high temperature limit switches can be connected into the facility alarm system providing a more reliable means of monitoring area temperature. Finally, emergency generators should be considered where electrical power is critical for temperature control and the primary source is not reliable. 

Due to the incorporation of VRLA products into such new applications as HEV and photovoltaics/wind/hydro-electric energy conversion, or RAPS (remote-area power sources), the development of cycling algorithms involving a relatively narrow SoC window has emerged. While it is beyond the scope of this review to cover this topic in great depth, a general overview will be presented. 

Industrial batteries are used for telephones, communications, electric transformations, various types of emergency power sources, etc. The Waste Disposal Law provides that the companies shall properly dispose of the waste they produce with their commercial activities, as their own responsibility (Clause 1, Article 3). Thus, the law requires the users themselves to properly dispose of the batteries as industrial waste. 

Domestic sales for 1998 amounted to 316 million cells, i.e. 21% of total. Table 3.4 shows the sales ratios by applications. In the field of security and emergency, only NiCd batteries were sold. However, in the fields of offiee equipment and communications, the Li-ion battery ratio was 69% and 53%, respectively. In the fields of home appliances, electric tools toys and retail, the NiCd battery ratio was 51%, 84% and 63%, respectively. A ratio of 37% for NiMH batteries was found in retail (replacement). This seems to come from its use as the main power source for digital cameras. 

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