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This standard replaces EJ 878-1994 Safety design guidelines for away-from-reactor storage pool used for spent fuel.
The following main changes have been made with respect to EJ 878-1994:
——The application scope of the standard is expanded;
——The storage and treatment measures for damaged spent fuel are improved;
——Various design basis parameters such as pool water cooling and purification systems are checked based on the recent operating experience of independent spent fuel storage installations at home and abroad;
——The design basis ground motion load shall be considered in accordance with SL2, and its peak acceleration is changed from "not less than 0.1g" to "not less than 0.15g";
——The contents of Annexes A, B and C are revised according to the situation when storing deep burn-up spent fuel (for example, the average fuel consumption is 5.5×104 MWd/tU).
Annexes A, B, C and D to this standard are informative.
This standard was proposed by China National Nuclear Corporation.
This standard is under the jurisdiction of the Institute for Standardization of Nuclear Industry.
This standard was issued in October 1994 for the first time.
Design criteria for independent spent fuel storage installation (water pool type)
1 Scope
This standard specifies the criteria and basic requirements to be followed in the design of independent spent fuel storage installation (hereinafter referred to as "ISFSI") to ensure nuclear safety.
This standard is applicable to the safety design of ISFSIs for storage of spent fuel discharged from water reactors and cooled for more than five years. It is also applicable to the safety design of ISFSIs for storage of other types of spent fuel (for example, discharged from gas cooled reactors) and components of fuel assemblies.
It is not applicable to the safety design of the pool located within the reactor site.
2 Normative references
The following normative documents contain provisions which, through reference in this standard, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply to this standard. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition applies.
GB 15146.8 Nuclear criticality safety for fissile materials outside reactors - Part 8: Criticality safety criteria for the handling storage and transportation of LWR fuel outside reactors
GB 18871 Basic standards for protection against ionizing radiation and for the safety of radiation sources
GB 50010 Code for design of concrete structures
GB 50016 Code for fire protection design of buildings
GB 50017 Code for design of steel structures
EJ 724 Fire protection criteria of nuclear fuel reprocessing plant
EJ 849 Specification on radiation safety design of nuclear fuel reprocessing plant
EJ/T 939 Classification for structures, systems and components of nuclear fuel reprocessing plant
EJ/T 1054 Physical protection of nuclear material and nuclear facilities
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3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
independent spent fuel storage installation (ISFSI)
spent fuel storage installation located outside the boundary of the reactor area, which is usually used to receive and store spent fuel from several reactors
3.2
fuel unit
object treated as a single article during operation, storage, or transportation, which may be a single fuel element, a fuel assembly, spent fuel in a tank, or a batch of fuel elements that are densely packed together
3.3
basket
metal member with opening, used for transferring or storing one or more spent fuel units
3.4
storage racks
metal member set in the pool and used for supporting and holding the fuel unit so that the fuel unit is in a subcritical state during storage
3.5
basket brackets
metal member arranged on the bottom or wall of the pool and used for supporting the storage basket and ensuring that the fuel in the basket is in a subcritical state under any circumstances
3.6
design basis accident (DBA)
accident condition in which specific measures have been taken in the design of the ISFSI according to the determined design criteria. For example:
a) nuclear criticality accident;
b) loss of pool water cooling function;
c) container falling;
d) occurrence of a design basis earthquake.
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4 Safety Criteria
4.1 Main safety objective
The main safety objective is to protect the staff, the public and the environment, to ensure that the exposure to the staff and the public under all operating conditions and accident conditions does not exceed the limit value specified by the nation, and to implement the principle "as low as reasonably practicable" in the design.
4.2 Safety principles
The principle of "safety first" shall be followed. In-depth defense shall be reflected and multilevel protection shall be provided in design so as to ensure the normal operation of the ISFSI, prevent accidents, and limit the development and consequences of accidents.
4.3 Overall basis of safety design
The safety design of the ISFSI shall comply with relevant regulations and standards of the nation and this standard.
4.4 Quality assurance
The buildings (structures), systems, and components important to safety of the ISFSIs shall be classified according to their safety functions, and the quality assurance requirements that match the importance of completing their safety functions shall be put forward.
4.5 Plant site characteristics and protection against natural events
4.5.1 The design shall take into account the mutual influence between the ISFSI and the environmental factors (such as population, meteorological, hydrological, geological and seismic conditions, and other related facilities) of the plant site.
4.5.2 The design of buildings (structures), systems, and components important to safety of the ISFSIs shall take into account that they still maintain their safety functions under the natural events (such as earthquake, tornado, lightning, hurricane, flood, tsunami, lake surge and debris flow) that may occur at the plant site. The intensity of various natural events that may occur shall be determined to determine the design basis for items important to safety. The design shall also take into account that due to the uncertainty of the data source of the most severe natural event, the limitation of the data accumulation time period and other factors, the design shall have an appropriate margin when considering the most severe natural event at the plant site and its surrounding area.
Foreword II
1 Scope
2 Normative references
3 Terms and definitions
4 Safety Criteria
5 Basic requirements for safety design
Annex A (Informative) Schematic diagram for technology process of ISFSI
Annex B (Informative) Recommended physical-chemical properties of the pool water
Annex C (Informative) Conservative generation rate of decay heat of pressurized water reactor spent fuel
Annex D (Informative) Typical dose rates
