GB/T 47505-2026 Habitability assessment methodology for emergency facility of nuclear power plants English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS
CCS
National Standard of the People's Republic of China
GB/T 47505-2026
Habitability assessment methodology for emergency facility of nuclear power plants
核动力厂应急设施可居留性评价方法
Issue date: 2026-03-31 Implementation date: 2026-10-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1.0Scope .
2.Normative References
3.Terms and Definitions
4.General Requirements
4.1 General
4.2 Evaluation of Radioactive Release Accidents
4.3 Evaluation of Toxic and Hazardous Gas Release Accidents
Analysis Method for Atmospheric Dispersion Factors
5.1 General
5.2 Meteorological Data Requirements
5.3 Calculation Method for Short Range Atmospheric Dispersion Factors
5.4 Calculation Method for Long Range Atmospheric Dispersion Factors
6 Evaluation Method for Habitability in Radioactive Release Accidents
Evaluation Method for Habitability in Toxic and Hazardous Gas Release Accidents .
7.1 Hazard Source Screening .
7.2 Accident Scenarios
7.3 Calculation of Toxic Gas Concentration
7.4 Evaluation Method ...... 1Annex A (Informative) Calculation Method for Short Range
Annex B (Informative) Calculation Method for Long Range Atmospheric Dispersion Factors
B.1 Calculation Model for Ground Level Releases
B.2 Calculation Model for Annual Average Atmospheric Dispersion Factors
Annex C (Informative) Evaluation Method for Habitability of Emergency Facilities in Radioactive Release Accidents
C.1 Calculation Model for Radionuclide Concentration in Habitable Areas
Evaluation method for habitability of emergency facilities at nuclear power plants
1 Scope
This document specifies the general requirements for the evaluation of the habitability of emergency facilities within nuclear power plant buildings, and describes the analysis method for atmospheric dispersion factors, the evaluation method for habitability in radioactive release accidents, and the evaluation method for habitability in toxic and hazardous gas release accidents.
This document applies to the evaluation of the habitability of emergency facilities such as the main control room, the emergency control centre and the technical support centre at nuclear power plants. Other types of nuclear facilities may refer to this document.
2 Normative References
The contents of the following documents constitute indispensable provisions of this document through normative references. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.GB 6249 Regulations for environmental radiation protection of nuclear power plants
HJ 169—2018 Technical guidelines for environmental risk assessment of construction projects
NB/T 20567 Technical specification for construction of meteorological observation system and data statistical analysis for nuclear power plants
HAD 002/01 Preparedness and response for a nuclear or radiological emergency of the operating organisation for nuclear power plants3 Terms and definitions
The following terms and definitions apply to this document.
3.1 habitability
A description of the degree to which an area is suitable for continuous or temporary occupation.
Source: GB/T 17680.7—2025, 3.4Source: GB/T 17680.7—2025, 3.4
3.2 emergency facility
Emergency response areas, together with their systems and equipment, established in accordance with relevant regulatory requirements and based on the principles of relevant standards.
Source: GB/T 17680.7—2025, 3.1Source: GB/T 17680.7—2025, 3.1
3.3 habitable area
The area enclosed by the external enclosing boundary of the facility.
NOTE: It should be explained how the habitable area is isolated from other areas or rooms.
3.4 design basis source term
The reference source term used for the design of the habitability of emergency facilities.
NOTE: This source term considers core melt.
3.5 atmospheric dispersion factor
The relative concentration of radioactive material in ambient air at a given point resulting from the release of radioactive material.
3.6
wind direction window
A defined angular range, with the release point as the apex and the line connecting the release point to the receptor point as the axis of symmetry.
NOTE: Generally refers to a wedge-shaped area with the release point as the apex, the line connecting the release point and the air intake as the centre line, extending 45° on each side.
3.7
immediately dangerous to life and health concentration; IDLH
A chemical concentration level that may cause death, serious health damage or hinder escape.
4 General requirements
4.1 General
To ensure the safety of staff and the emergency response capability within emergency facilities under accident conditions, the habitability of the emergency facilities shall be evaluated.
For the main control room, the habitability evaluation should not be limited to radioactive release accident scenarios; the potential impact of toxic and hazardous gas releases shall also be considered, taking into account the site characteristics.
4.2 Evaluation of radioactive release accidents
The habitability evaluation for emergency facilities should not be limited to design basis accidents; the impact of accidents leading to core melt shall be appropriately considered.
In the analysis and evaluation of habitability for radioactive release accidents, the contribution to the dose received by staff from exposure pathways such as indoor air immersion external exposure, inhalation internal exposure and outdoor plume immersion external exposure in the habitable area after an accident shall be fully considered.
For the design basis accident source term and the design basis source term, the emergency facilities shall meet the habitability criteria specified in HAD 002/01, i.e., during a defined continuous emergency response period (generally 30 days), the effective dose received by staff shall not be greater than 50 mSv, and the thyroid equivalent dose shall not be greater than 500 mSv.
4.3 Evaluation of toxic and hazardous gas release accidents
For hazardous chemicals, the habitability evaluation for the main control room shall include:
a) Screening of hazardous chemicals based on their hazardous characteristics and storage quantities to determine the types of chemicals that need to be evaluated;
b) Analysis of the toxic gas concentration level inside the main control room and comparison with the immediately dangerous to life and health concentration (IDLH) for evaluation.
5 Analysis method for atmospheric dispersion factors
5.1 General
The appropriate method for calculating the atmospheric dispersion factor shall be selected based on the distance between the air intake of the emergency facility and the release point. For the main control room, the method in 5.3 should be used; for the emergency control centre, the method in 5.3 or 5.4 may be used.
When a toxic or hazardous gas is determined to be a dense gas according to the method in G.2 of HJ 169—2018, the gas concentration calculation shall use the SLAB model. The SLAB model is applicable to the dispersion simulation of dense gas emissions over flat terrain. If other technically mature atmospheric risk prediction models other than the recommended model are used, the justification for the model selection and its applicability shall be provided.
Standard
GB/T 47505-2026 Habitability assessment methodology for emergency facility of nuclear power plants (English Version)
Standard No.
GB/T 47505-2026
Status
valid
Language
English
File Format
PDF
Word Count
14500 words
Price(USD)
435.0
Implemented on
2026-4-30
Delivery
via email in 1~5 business day
Detail of GB/T 47505-2026
Standard No.
GB/T 47505-2026
English Name
Habitability assessment methodology for emergency facility of nuclear power plants
GB/T 47505-2026 Habitability assessment methodology for emergency facility of nuclear power plants English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS
CCS
National Standard of the People's Republic of China
GB/T 47505-2026
Habitability assessment methodology for emergency facility of nuclear power plants
核动力厂应急设施可居留性评价方法
Issue date: 2026-03-31 Implementation date: 2026-10-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1.0Scope .
2.Normative References
3.Terms and Definitions
4.General Requirements
4.1 General
4.2 Evaluation of Radioactive Release Accidents
4.3 Evaluation of Toxic and Hazardous Gas Release Accidents
Analysis Method for Atmospheric Dispersion Factors
5.1 General
5.2 Meteorological Data Requirements
5.3 Calculation Method for Short Range Atmospheric Dispersion Factors
5.4 Calculation Method for Long Range Atmospheric Dispersion Factors
6 Evaluation Method for Habitability in Radioactive Release Accidents
Evaluation Method for Habitability in Toxic and Hazardous Gas Release Accidents .
7.1 Hazard Source Screening .
7.2 Accident Scenarios
7.3 Calculation of Toxic Gas Concentration
7.4 Evaluation Method ...... 1Annex A (Informative) Calculation Method for Short Range
Annex B (Informative) Calculation Method for Long Range Atmospheric Dispersion Factors
B.1 Calculation Model for Ground Level Releases
B.2 Calculation Model for Annual Average Atmospheric Dispersion Factors
Annex C (Informative) Evaluation Method for Habitability of Emergency Facilities in Radioactive Release Accidents
C.1 Calculation Model for Radionuclide Concentration in Habitable Areas
Evaluation method for habitability of emergency facilities at nuclear power plants
1 Scope
This document specifies the general requirements for the evaluation of the habitability of emergency facilities within nuclear power plant buildings, and describes the analysis method for atmospheric dispersion factors, the evaluation method for habitability in radioactive release accidents, and the evaluation method for habitability in toxic and hazardous gas release accidents.
This document applies to the evaluation of the habitability of emergency facilities such as the main control room, the emergency control centre and the technical support centre at nuclear power plants. Other types of nuclear facilities may refer to this document.
2 Normative References
The contents of the following documents constitute indispensable provisions of this document through normative references. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.GB 6249 Regulations for environmental radiation protection of nuclear power plants
HJ 169—2018 Technical guidelines for environmental risk assessment of construction projects
NB/T 20567 Technical specification for construction of meteorological observation system and data statistical analysis for nuclear power plants
HAD 002/01 Preparedness and response for a nuclear or radiological emergency of the operating organisation for nuclear power plants3 Terms and definitions
The following terms and definitions apply to this document.
3.1 habitability
A description of the degree to which an area is suitable for continuous or temporary occupation.
Source: GB/T 17680.7—2025, 3.4Source: GB/T 17680.7—2025, 3.4
3.2 emergency facility
Emergency response areas, together with their systems and equipment, established in accordance with relevant regulatory requirements and based on the principles of relevant standards.
Source: GB/T 17680.7—2025, 3.1Source: GB/T 17680.7—2025, 3.1
3.3 habitable area
The area enclosed by the external enclosing boundary of the facility.
NOTE: It should be explained how the habitable area is isolated from other areas or rooms.
3.4 design basis source term
The reference source term used for the design of the habitability of emergency facilities.
NOTE: This source term considers core melt.
3.5 atmospheric dispersion factor
The relative concentration of radioactive material in ambient air at a given point resulting from the release of radioactive material.
3.6
wind direction window
A defined angular range, with the release point as the apex and the line connecting the release point to the receptor point as the axis of symmetry.
NOTE: Generally refers to a wedge-shaped area with the release point as the apex, the line connecting the release point and the air intake as the centre line, extending 45° on each side.
3.7
immediately dangerous to life and health concentration; IDLH
A chemical concentration level that may cause death, serious health damage or hinder escape.
4 General requirements
4.1 General
To ensure the safety of staff and the emergency response capability within emergency facilities under accident conditions, the habitability of the emergency facilities shall be evaluated.
For the main control room, the habitability evaluation should not be limited to radioactive release accident scenarios; the potential impact of toxic and hazardous gas releases shall also be considered, taking into account the site characteristics.
4.2 Evaluation of radioactive release accidents
The habitability evaluation for emergency facilities should not be limited to design basis accidents; the impact of accidents leading to core melt shall be appropriately considered.
In the analysis and evaluation of habitability for radioactive release accidents, the contribution to the dose received by staff from exposure pathways such as indoor air immersion external exposure, inhalation internal exposure and outdoor plume immersion external exposure in the habitable area after an accident shall be fully considered.
For the design basis accident source term and the design basis source term, the emergency facilities shall meet the habitability criteria specified in HAD 002/01, i.e., during a defined continuous emergency response period (generally 30 days), the effective dose received by staff shall not be greater than 50 mSv, and the thyroid equivalent dose shall not be greater than 500 mSv.
4.3 Evaluation of toxic and hazardous gas release accidents
For hazardous chemicals, the habitability evaluation for the main control room shall include:
a) Screening of hazardous chemicals based on their hazardous characteristics and storage quantities to determine the types of chemicals that need to be evaluated;
b) Analysis of the toxic gas concentration level inside the main control room and comparison with the immediately dangerous to life and health concentration (IDLH) for evaluation.
5 Analysis method for atmospheric dispersion factors
5.1 General
The appropriate method for calculating the atmospheric dispersion factor shall be selected based on the distance between the air intake of the emergency facility and the release point. For the main control room, the method in 5.3 should be used; for the emergency control centre, the method in 5.3 or 5.4 may be used.
When a toxic or hazardous gas is determined to be a dense gas according to the method in G.2 of HJ 169—2018, the gas concentration calculation shall use the SLAB model. The SLAB model is applicable to the dispersion simulation of dense gas emissions over flat terrain. If other technically mature atmospheric risk prediction models other than the recommended model are used, the justification for the model selection and its applicability shall be provided.
