IEEE Std 308-2020 pdf download

IEEE Std 308-2020 pdf download.IEEE Standard Criteria for Class 1E Power Systems for Nuclear Power Generating Stations.
passive reactor design: A reactor design that uses forces of nature, such as fluid density differences and heat transfer, to create natural circulation cooling on a scale sufficient to replace large active components for accident and operational event response. This eliminates the need for forced coolant circulation and associated active components requiring Class 1 E ac power for accident and operational event response.
power sources: The electrical and mechanical equipment and interconnections necessary to generate or convert power.
NOTE—Electric powcr source and power supply are interchangeable within the context of this document.
preferred power supply: The power supply from the transmission system to the Class I E distribution system that is preferred to furnish electric power under accident and post-accident conditions.
programmable digital device: A device that can store instructions and is capable of executing a systematic sequence of operations performed on data that is controlled by internally stored instructions.
protection system: The part of the sense and command features involved in generating the signals used primarily for the reactor trip system and engineered safety features.
protective action: The initiation of a signal within the sense and command features, or the operation of equipment within the execute features, to accomplish a safety function.
redundant equipment or system: A piece of equipment or a system that duplicates the essential function of another piece of equipment or system to the extent that either may perform the required function regardless of the state of operation or failure of the other.
NOTE—Redundancy can be accomplished by using identical equipment, equipment diversity, or functional diversity.
safety class structures: Structures designed to protect Class 1 E equipment against the effects of design basis events.
safety function: One of the processes or conditions (e.g., emergency negative reactivity insertion, post- accident heat removal, emergency core cooling, post-accident radioactivity removal, containment isolation) essential to maintain plant parameters within acceptable limits established for a design basis event.
NOTE—A safety function is achieved by the completion of all required protective actions by the reactor trip system and the engineered safety features, or both, concurrent with the completion of all required protective actions by the auxiliary supporting features.
safety group: A given minimal set of interconnected components, modules, and equipment that can accomplish a safety function.
NOTE—A safety group may include one or more divisions. In a design rhere each division can accomplish a safety function, each division is a safety group. however, a design consisting of three 50% capacity systems separated into three divisions would have three safety groups; any two out of three divisions are required to be operating to accomplish the safety function.
a) The integrity of the reactor coolant pressure boundary
b) The capability to shut down the reactor and maintain it in a safe shutdown condition
c) The capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposures comparable to the 10 CFR Part 100 guidelines
sense and command features: The electrical and mechanical components and interconnections involved in generating the signals associated directly or indirectly with the safety functions. The scope of the sense and command features extends from the measured process variables to the execute features input terminals.
significant: Demonstrated to be important by the safety analysis of the station.
standby power supply: The ac power supply that is selected to furnish electric energy when the preferred power supply is not available.
unit: A nuclear steam supply system and its associated turbine-generator, auxiliaries, and engineered safety features.
verification and validation: The process of determining whether the requirements for a system or component are complete and correct, the products of each development phase fulfill the requirements or conditions imposed by the previous phase, and the final system or component complies with specified requirements.
4. Principal design criteria
4.1 General
Class 1 E power systems shall be designed to provide that no design basis event causes the following:
A loss of electric nower to a number of engineered safety features. surveillance levices. or nrotection.