This standard specifies the environmental radiation protection requirements for the site selection, design, construction, operation, decommissioning, expansion and modification of the overland fixed nuclear power plant.
This standard is applicable to the overland fixed nuclear facilities powered by the light water reactor or heavy water reactor; other reactor-type nuclear power plants may be executed by reference.
2 Normative References
This standard refers to the provisions of the following documents. For the undated normative references, the effective version is applicable to this standard.
GB 18871-2002 Basic Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources
3 Terms and Definitions
The following terms and definitions are applicable to this standard.
3.1 Exclusion area
It refers to in a certain range around the reactor where it is forbidden to have the residents; nuclear power plant operator exercises effective control, including individual and property evacuation; highway, railway and waterway can cross this area, but nuclear power plant normal operation shall not be disturbed; in case of accident, proper and effective arrangement can be made and traffic can be controlled so as to guarantee the safety of staff and residents. In exclusion area activities not related to nuclear power plant operation are allowed if it does not affect nuclear power plant normal operation and endanger residents.
3.2 Planning restricted area
It refers to the area directly near to the exclusion area confirmed by the provincial People's Government. In the planning restricted area, mechanical increase of the population must be limited; the construction and extension projects shall be directed or limited to consider the possibility to adopt proper protective measures in the accident emergency state.
3.3 Multi-reactor site
It refers to the plant site of the nuclear power plant where there are more than two reactors in each plant site and the distance among each reactor is less than 5km.
3.4 Dose constraint
It refers to a kind of predetermined limitation on the personal dose cause possibly by the source; it is relevant to the source and used as the constraint condition when the source is in the protection and safety optimization. For the public exposure, the dose constraint is the upper bound of annual dose received by the public member from the planning operation of a controlled source. The expose of dose constraint refers to the total number of received annual dose by any critical group during the anticipated operation process of the controlled source and through all the exposure pathways. The dose constraint for each source shall ensure the total number of the dose from the entire controlled source received by the critical group shall within the dose limit.
3.5 Environmental sensitive area
It refers to the area with the features of the area needed to be protected specially, ecologic sensitive and weakness area and the society concern area.
3.6 Radioactive effluents
It refers to, under usual conditions, the radioactive substance which is emitted into the environment by the nuclear power plant in the form of gas, aerosol, dust and liquid and be diluted and dispersed.
3.7 Operational states
It refers to the general name of normal operation state and anticipated operational occurrences state. The normal operation refers to the operation of the nuclear power plant in the specified operation limit and condition. The anticipated operational occurrences refer to all kinds of deflection operational process of the nuclear power plant happened at least one in the operation lifespan; due to the corresponding measures taken in the planning, this kind of accident will not lead to the serious damage of the item important to safety or the accident condition.
3.8 Accident conditions
It refers to the condition more serious than the anticipated operational occurrences, including design basis accident and severe accident.
3.9 Design basis accident
It refers to the accident condition happened when the nuclear power plant designs according to the determinate design criteria and takes corresponding measures in the design; the damage of fuel and release of radioactive substance are ensured not to exceed the accident control value.
Design basis accident includes infrequent accident and limiting accident.
3.10 Infrequent accidents
It refers to the accident with low occurrence frequency in the operation lifespan of the nuclear power plant (10-4~10-2/reactor year estimated); this kind of accident may lead to the damage to the little fuel element, but the single infrequent accidents will not lead to the loss of the function of the reactor coolant system or containment shell barrier.
3.11 Limiting accidents
It refers to the accident with extremely low occurrence frequency in the operation lifespan of the nuclear power plant (10-4~10-2/reactor year estimated); the results of this kinds of accident include the possibility of release of lots of radioactive substance, but the single limiting accident will not lead to the loss of the function of the system (including emergency core cooling system and containment shell) required to reply the accident.
3.12 Postulated siting accident
This accident is only applicable to the examination and approval stage of the plant site, as a reference to determine the border of the exclusion area and planning restricted area of the plant site. For the water cooled reactor, the complete reactor core fusion shall be considered, or the full and effective demonstration shall be carried out.
3.13 Severe accidents
It refers to the accident condition whose severity exceeds the design basis accident and leads to obvious deterioration of the reactor core.
