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HAD 102/04-2019
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Standard similar to HAD10204-2019 HAD 102/13 HAD 102/10 HAD 102/02 Basic data | Standard ID | HAD 102/04-2019 (HAD102/04-2019) | | Description (Translated English) | (Protection design of internal dangers (except fire and explosion) in nuclear power plants) | | Sector / Industry | Chinese Industry Standard | HAD10204-2019: (Protection design of internal dangers (except fire and explosion) in nuclear power plants)
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HA D10204-2019
(Protection design of internal dangers (except fire and explosion) in nuclear power plants)
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Annex 2
Nuclear Safety Guide HA D 102/04–2019
Internal hazards of nuclear power plants (fire and explosion
except) protective design
(Approved and released by the National Nuclear Safety Administration on December 31,:2019
National Nuclear Safety Administration
Design of protection against internal hazards (other than fire and explosion) in nuclear power plants
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1 Introduction
1:1 Purpose
This guideline is a reference to the "Safety Regulations for the Design of Nuclear Power Plants" (HA F102, hereinafter referred to as
"Regulations") the description and elaboration of the relevant provisions, the purpose of which is to evaluate the internal
The possible consequences of Ministry Hazard 1, as well as analysis methods and procedures, provide guidance: This guideline may
For use by nuclear safety supervision and management departments, nuclear power plant designers and licensees
use:
1:2 Scope
1:2:1 These Guidelines are applicable to onshore stationary thermal neutron reactor nuclear power plants: Book
The examples given in the guidelines are generally derived from light water reactor nuclear power plants, but the recommendations given are generally
Often also applies to other types of thermal neutron reactor nuclear power plants:
1:2:2 This guideline discusses the different operations of nuclear power plants described in the Regulations
Hypothetical Initiating Event 2 that may occur in the state, and supplements the relevant chapters:
This guideline uses probabilistic and deterministic methods to evaluate the following:
(1) Assume initiating events, use deterministic methods to make assumptions, and use
Probabilistic method to estimate its frequency;
(2) The likelihood or frequency of impact on structures, systems and components3;
1 Internal hazards are hazards that occur within the site boundaries, within the operating area of a nuclear power plant: Internal risks studied in this guideline
Risk excludes fire and explosion:
2 It is assumed that an initiating event is an event identified during the design phase that can lead to an expected operational event or accident condition: hypothetical event
The main causes of incidents can be credible equipment failures, personnel errors (both inside and outside the facility), and human or automatic failures:
incident:
3 Structures, systems and components are all items or activities (except personnel
other than wrong): Structures are inactive animal items, including buildings, containers, shields, etc: The system includes a
The sum of several components that are grouped together in a way to perform a specific (active) function:
Design of protection against internal hazards (other than fire and explosion) in nuclear power plants
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(3) Likelihood or frequency of damaging consequences;
(4) A comprehensive evaluation of the consequences and a judgment on their acceptability:
1:2:3 This guideline describes the consequences of hypothetical initiating events (including secondary and cascading effects)
should) analysis, and the corresponding functional analysis to provide guidance: Protection is also discussed in this guideline
Internal hazards and measures to reduce the relevant frequencies in Section 1:2:2:
1:2:4 These guidelines will evaluate the following internal hazards: projectiles, collapse of structures and
Falling objects, damage to pipes and their consequences, pipe swings, jet effects and flooding: right
For each hazard, this guideline will describe the hypothetical initiating event and discuss precautionary and protective measures:
specific measure: other internal hazards (such as vehicle impact on structures, systems and components,
releases of toxic or asphyxiating gases) are not covered in these Guidelines:
1:2:5 For existing nuclear power plants, some design proposals may be difficult in practice:
to achieve: Recommendations involving maintenance, surveillance and in-service inspections should be
If it is not feasible, the analysis of failure consequences should also be considered:
2 General Considerations
2:1 Hypothetical initiating event
2:1:1 The Regulations put forward the requirements and concepts for the safety design of nuclear power plants:
Hypothetical initiating events are defined in the glossary: Hypothetical originating events may challenge any layer
The second defense in depth must be considered during the design process: Hypothetical origin under consideration
Incidents should include internal hazards:
2:1:2 According to the requirements of the "Regulations", on the basis of probability theory and determinism
The selected hypothetical initiating event, the sensitivity of the plant design to it should be minimized:
Appropriate preventive and mitigating measures should be provided to deal with the impact of a postulated initiating event: This guide
Design of protection against internal hazards (other than fire and explosion) in nuclear power plants
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These will be described in detail:
2:2 Acceptability Considerations
2:2:1 According to the general principle of defense in depth, the nuclear power plant design should consider:
(1) Prevent or limit the occurrence of a hypothetical initiating event;
(2) Protection of structures, systems and components (to bring and maintain
necessary for a full shutdown state, or whose failure would result in an unacceptable release of radioactivity)
immunity from all possible effects of the assumed originating event under consideration;
(3) Robustness of structures, systems and components (e:g: quality appraisal);
(4) Other measures, such as possible inherent safety features,
Redundant designs, diverse systems, and physical segregation:
2:2:2 The safety evaluation of any equipment failure shall include the assumed initiating event and
its effects, except in the following cases:
(1) Assume that the frequency of initiating events (denoted as P1) is acceptably low
to the extent (see 2:2:9, 2:2:10) that consideration of its consequences can be excluded
necessary;
(2) The frequency at which the system or component is affected (denoted as P2) is sufficiently low (see 2:2:9,
2:2:10);
(3) If the system is affected, the frequency at which it results in unacceptable consequences 4 (representing
P3) is sufficiently low (see 2:2:9, 2:2:10);
(4) The overall frequency of unacceptable consequences (denoted as P) is sufficiently low (see 2:2:9,
4 Unacceptable consequences mean the loss of one or more of the three safety functions defined by the safety requirements of the Regulations:
Losses: (1) Control reactivity; (2) Discharge core heat; (3) Contain radioactive materials and control operational emissions and limits
Accident release:
Design of protection against internal hazards (other than fire and explosion) in nuclear power plants
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2:2:10): P is equal to the product of P1, P2 and P3: Estimates of P should take into account multiplicity
and other beneficial design features, as well as the possibility of common cause failure, false
unavailability of equipment and the occurrence of other adverse events:
2:2:3 Examples of ways to reduce these frequencies are as follows:
(1) Conservative design can reduce P1;
(2) Some measures are taken on the deployment, such as physical isolation between the source and the target 5,
P2 can be reduced;
(3) Comprehensive design and identification of potentially affected targets can reduce P3;
(4) P can be minimized by applying appropriate operating procedures: For example, put
Minimize the frequency of accidental flooding (impact on P1) or take effective
Action to avoid the spread of flooding (impact on P2):
2:2:4 The deterministic approach holds that the above approach excludes the occurrence of hypothetical initiating events:
health and/or its unacceptable impact on safety, i:e: at least considered frequencies P1, P2 or
One of P3 will drop to zero: The probabilistic approach will prioritize the use of comprehensive nuclear power plant
Unique reliability data that would otherwise complement the deterministic approach:
2:2:5 In order of priority, the best design approach is to actually eliminate false
set the initiating event (P1 reduced to acceptable); followed by the structure, system and component
Isolation from source (P2 reduced to acceptable); making consequences acceptable is also an option (P3
reduced to acceptable): The effectiveness of the second level of defense in depth should be ensured as far as possible:
When necessary, the effectiveness of the third layer should also be ensured to maintain the defense in depth: in some cases
Can require the use of a combination of all three layers of defense:
5 Targets are the safety-relevant structures, systems and components involved in the source:
Design of protection against internal hazards (other than fire and explosion) in nuclear power plants
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2:2:6 In the design of nuclear power plants, for the quality
Components with similar standard and operating conditions can be analyzed by analyzing the frequency P1 of a component
to analyze the hazards associated with such components:
2:2:7 In the design of the nuclear power plant, in order to
The installation of the object on the subfloor precludes it from being a hypothetical initiating event) and/
or P2 (e:g: choosing the appropriate method for the turbine generator relative to the reactor building layout)
bit) is reduced to a minimum, and the prevention of internal hazards should be considered when determining the deployment of nuclear power plants:
protect: The extent of this minimization depends largely on the details of the plant layout and equipment:
2:2:8 During the design or modification of a nuclear power plant, the analysis described in this guideline has been
The process can be used as an optimization tool to reduce one or more Pi factors (P1, P2 or
P3) Make design changes: In the method of probability theory, this analysis process can be applied to protect the
provide a basis for the acceptability of the meter:
2:2:9 The frequency and consequences of rare events are based on confidence (the
It depends on the items that can be effectively controlled: it means
In one case the main concern is reducing P1, in another case the main concern is
Decrease P2 or P3: To deal with uncertainty in quantifying P1, P2, or P3, the appropriate
Combine analytical and experimental work locally to determine worst-case and conservative
estimate:
2:2:10 Due to uncertainty in the quantification of particularly severe consequences or the estimated
Probabilistic confidence is insufficient, and some measures should be taken for the uncertainty of related risks (such as
methods of surveillance, monitoring, inspection, shielding and physical isolation) for special attention:
2:2:11 Risk-based considerations should clearly identify those possible hazards and
Design of protection against internal hazards (other than fire and explosion) in nuclear power plants
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Detailed and comprehensive consideration is required, while other hazards require only a cursory evaluation: sometimes give
The limit frequency of certain maximum consequence events, and the risk below this frequency is considered to be possible
Accepted 6: More often, the indicator value is heuristic and the probability limit is ambiguous
of: In such cases, calculations based on deterministic methods (eg stress analysis, fracture
calculations for mechanical or impact damage analysis) and engineering judgment to address each case separately
make decisions:
2:3 Analysis of quadratic and cascading effects
2:3:1 It is assumed that damage caused directly by the initiating event is called a primary effect: Assumption
The damage caused indirectly by the event through some failure mechanism of damage expansion is called secondary damage:
secondary effect: Damage caused by secondary effects may exceed primary effects: When it is necessary to make assumptions about
When the safety evaluation of the equipment failure is carried out to prove that the basic safety functions of the nuclear power plant are met,
The evaluation should include all secondary effects: In some cases, the assumptions discussed in this
The initiating event can be thought of as a secondary effect of another hypothetical initiating event (e:g: pipe swing can
secondary projectiles, etc:):
2:3:2 The characteristic of secondary effects is that the degree of damage they may cause varies greatly,
Many factors outside the designer's control come into play, so those that can
Take measures to stop the cascading effect, i:e: reduce P1 and/or P2 but not P3
Shi: Special care should be taken to prevent pipeline rupture as it can lead to several potential assumptions
Initiating events occur (eg flooding, pipe whipping, and jetting effects):
2:3:3 The nuclear power plant design should consider the secondary and
Cascading effect: After construction is completed, it shall be validated through a systematic and comprehensive approach, and
6 Depending on the method involved and the facility of interest, an acceptable frequency P is defined as less than 10-7 to 10-6 per year:
Design of protection against internal hazards (other than fire and explosion) in nuclear power plants
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Supplement relevant design measures to ensure that all possibilities are considered: One way is
Use a checklist of all possible secondary effects and explain them
shall not result in unacceptable consequential damage, and this method shall be compensated by inspection
Charge:
2:3:4 The following important secondary effects should be evaluated in the full analysis:
2:3:4:1 Secondary projectiles
Secondary projectiles (such as concrete blocks or
parts), which may cause unacceptable damage: In general, summarizing these
Characterization of secondary projectiles is difficult; the safest course of action is to prevent them from
It is limited to the source: For example, pipes with sufficiently high ductility and fracture toughness are unlikely to be
Multiple pipe ruptures can occur spontaneously causing pipe components to separate into secondary projectiles:
2:3:4:2 Object falling
If the pipe is thrown or the projectile damages the support structure of the heavy object located above the safety system
structure, which may result in further damage from falling objects: In some cases it should be demonstrated
Falling objects will not cause unacceptable damage: If it cannot be proven, the support should be modified
structures to withstand projectile impacts, or measures should be taken to prevent such impacts:
2:3:4:3 Failure of high-energy piping 7 and components
If an initiating event is assumed to result in a pipeline or component containing a large amount of energy storage fluid
rupture, this fluid energy may be released through the following ways or mechanisms to cause further
Damage: jetting, high pressure, pressure waves, rising temperature or humidity, pipe shaking, flooding,
Secondary projectiles, chemical reactions and high activity radioactivity: Rupture of high energy pipes and components
7 High-energy pipelines are defined as those with an internal operating pressure greater than or equal to 2:0 MPa and operating under the condition that the working medium is water:
Pipes with a temperature greater than or equal to 100 degrees Celsius, and possibly other limits for other fluids:
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