Anticipated operational occurrences AOOs

Anticipated Operational Occurrences (AOOs) These are families of... 

The structural effects of the five postulated anticipated operational occurrences (AOOs) on the reactor core are discussed in this section. The... 

The control assemblies shall incorporate features which ensure that the control rods and reserve shutdown material enter their designated channels for all reactor configurations resulting from anticipated operational occurrences (AOOs) and design basis events (DBEs). 

The plant anticipated operational occurrences (AOOs) are described in detail in Section 11.6. For the AOOs in which the outer control rods are tripped, the trip occurs quite early in the event, before there can be a significant temperature transient or environmental change affecting the equipment. For AOO-5 the trip may occur long after the event is initiated and there is no significantly detrimental transient Imposed on the CRDs prior to the time when they are signalled to release the rods. 

The plant anticipated operational occurrences (AOOs) are described in Section 11.6. Those which affect the reactor Internals are discussed below. 

The word emergency is used in many different contexts and different areas of human activity. In Ret [4] emergency is defined in part as A nonroutine situation or event that necessitates prompt action primarily to mitigate a hazard or adverse consequences for human health and safety, quality of life, property or the environment . In IAEA safety assessment publications the following terms have been established for identification of different operational states and accident conditions of a nuclear power plant normal operation, anticipated operational occurrences (AOOs) (abnormal operation), design basis accidents (DBAs), beyond design basis accidents (BDBAs) and severe accidents. 

According to INSAG-10 [3], defence in depth consists of a hierarchical deployment of different levels of equipment and procedures in order to maintain the effectiveness of physical barriers placed between radioactive material and workers, the public or the environment, during normal operation, anticipated operational occurrences (AOOs) and, for some barriers, accidents at the plant. 

The safety evaluation of the GTHTR300 has been performed considering its inherent safety characteristics and salient engineering features. The classification of the events to be evaluated is based on the HTTR and LWR safety evaluation guidelines. In LWR and HTTR safety evaluations, the Anticipated Operation Occurrence (AOO) is defined as the off-normal event with its frequency of roughly lower than approximately lO /reactor-year and the accident is defined as one with a frequency lower than approximately lO /reactor-year. A deterministic evaluation will be carried out for these AOOs and accidents. On the other hand. 

Criterion 42. Safety analysis of the plant design Anticipated operational occurrences (AOOs) and DBAs are evaluated in the safety analysis and include design of a physical protection system to protect against malevolent acts. 

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