1 General provisions
1.0.1 This standard is developed in order to implement the national laws and regulations on earthquake prevention and disaster reduction and nuclear safety, strictly follow the policy of safety first for civil nuclear facilities, and ensure the safe operation, reliable quality, advanced technology and economic rationality of nuclear power plants.
1.0.2 This standard is applicable to the seismic design of new PWR nuclear power plants in areas where the peak value of ultimate safety ground motion acceleration is not greater than 0.5 g, and its basic principles and seismic computation methods are also applicable to heavy water reactor, gas-cooled reactor and fast neutron reactor nuclear power plants.
1.0.3 The nuclear power plant sites must be subjected to evaluation for seismic safety, for which the design basis ground motion must be determined.
1.0.4 The nuclear power plants designed according to this standard, under the ultimate safety ground motion, shall be able to ensure that the reactor coolant pressure boundary is complete, the reactor is shut down safely and maintained in a safe shutdown state, and the impact of radioactive material release on the environment does not exceed the limits stipulated by China; such nuclear power plants, under the operational safety ground motion, shall be shut down for safety inspection, and can be resumed provided that the related SSCs of the nuclear power plants keep safety functions.
1.0.5 The seismic design of nuclear power plant SSCs shall meet the overall safety requirements of the plants; seismic design of nuclear power plant SSCs shall be carried out according to the seismic category, which shall correspond to the safety importance classification of nuclear power plant SSCs.
1.0.6 The nuclear power plant SSCs can be classified by seismic category into Category I seismic, Category II seismic and non-nuclear seismic SSCs. The seismic category of each specific SSC may follow the provisions of relevant technical standards.
1.0.7 The seismic design of Category I seismic and Category II seismic SSCs shall follow the methods specified in this standard; the seismic design of non-nuclear seismic SSCs shall not be lower than those specified in the current non-nuclear safety-related seismic design standards of the nation.
1.0.8 In addition to this standard, the seismic design of nuclear power plants shall also comply with the requirements of the current relevant standards of the nation.
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2 Terms and symbols
2.1 Terms
2.1.1 structure, system and component (SSC)
general term for buildings, structures, systems and components of a nuclear power plant
2.1.2 ground motion
earthquake-induced movement of earthcrust's rock and soil medium, expressed by time history of ground motion and corresponding parameters such as peak value, spectrum and duration
2.1.3 design basis ground motion
ground motion used as input in the seismic design of Categories I and II seismic SSCs in nuclear power plants, including two levels, i.e. ultimate safety ground motion and operational safety ground motion
2.1.4 ultimate safety ground motion
higher level of design basis ground motion of nuclear power plants, corresponding to the ultimate safety requirements, which is usually the predicted maximum potential ground motion that may be encountered in the nuclear power plant area, of which the corresponding annual exceeding probability is 10-4.
2.1.5 operational safety ground motion
lower level of design basis ground motion of nuclear power plants, mainly used for safety control of nuclear power plant operation, load combination and stress analysis in design, etc. This ground motion has different uses from the ultimate safety ground motion.
2.1.6 site-specific response spectra
design basis seismic response spectrum in consideration of seismic background and site characteristics of specific nuclear power plant site area
2.1.7 normalized response spectra
design basis seismic response spectrum with envelope spectrum characteristics without regard to seismic background and site characteristics of specific nuclear power plant site area
2.1.8 seismic precautionary intensity
seismic intensity approved as the seismic precautionary basis of non-nuclear engineering facilities in a region according to the authority prescribed by the state (generally the seismic intensity with exceeding probability of 10% during the 50 years is adopted)
2.1.9 required response spectra (RRS)
input response spectrum specified by relevant technical standards in seismic evaluation test of equipment
2.1.10 test response spectra (TRS)
input response spectrum actually used in seismic evaluation test of equipment
2.2 Symbols
2.2.1 Ground motion:
|F(f)|,|F(ω)|——the Fourier amplitude spectrum of stationary phase of ground motion acceleration time history;
S(f), S(ω)——the power spectrum of ground motion acceleration time history;
Td——the duration of stationary phase of ground motion acceleration time history;
a——the maximum ground motion acceleration at the elevation of the subterranean straight pipe;
amax——the peak acceleration of ground motion;
c——the apparent wave velocity of seismic waves propagating along pipes in foundation;
fmax——the maximum frequency of ground motion considered;
m1, m2——the mean of ground motion acceleration time histories x1(t) and x2(t) respectively;
{xb}——the input horizontal ground motion displacement vector of foundation;
υe——the maximum ground motion velocity at the elevation of the subterranean straight pipe;
λ——the apparent wavelength of seismic wave;
ρ12——the correlation coefficient between ground motion acceleration time histories x1(t) and x2(t);
σ1, σ2——the standard deviation of ground motion acceleration time histories x1(t) and x2(t) respectively.
2.2.2 Structural parameters and structural analysis:
Cx, Cz, Cφ——the damping coefficients of the base along the horizontal, vertical and swing directions respectively;
[C]——the damping matrix of the structure;
Kn, Kt——the subgrade bed coefficients along the axial and transverse directions of the pipe respectively;
Kx, Kz, Kφ——the spring stiffness of the foundation along the horizontal, vertical and swing directions respectively;
Kx′, Kz′, Kφ′——the spring stiffness of the foundation along the horizontal, vertical and swing directions respectively, when the base is placed on the ground surface;
Kx″, Kz″, Kφ″——the additional spring stiffness of the base along the horizontal, vertical and swing directions respectively, in consideration of the foundation embedment effects;
[K]——the stiffness matrix of structure;
[Ks]——the stiffness matrix of foundation spring;
M——the structural mass;
[M]——the structural mass matrix;
Rn(f)——the response spectrum;
Sa——the maximum spectrum value of the response spectrum of the floor where the equipment is located;
Sai——the response spectrum value corresponding to frequency i;
[S]——the dynamic impedance matrix;
[Ubs]——the displacement influence matrix;
ZPA——the acceleration spectrum value corresponding to zero period in the input response spectrum, i.e., the input acceleration peak value;
ZPAi——the zero-period acceleration spectrum value of response spectrum at the supporting point i;
fi, fj——the frequency corresponding to mode shape i and mode shape j respectively;
fn——the minimum natural frequency of a structure;
Kn, Kt——the foundation spring stiffness along the axial and transverse directions of the pipe respectively;
——the input acceleration vector of the structural system;
{xb(t)}——the input displacement vector at the supporting point;
——the input acceleration vector at the supporting point;
εij——the correlation coefficient between mode shape i and mode shape j;
ηx, ηz, ηφ——the radiation damping ratio of the foundation along horizontal, vertical and swing directions respectively;
ξ——the damping ratio;
ξi, ξj——the damping ratio corresponding to mode shape i and mode shape j respectively;
λm——the ratio of the total mass of the substructure to the total mass of the main structure;
λf——the ratio of the basic frequency of the substructure to the dominant frequency of the main structure;
ω1——the circular frequency of the basic natural vibration of a structure;
2.2.3 Actions and effects:
A——the load effect under accident conditions;
C——the load effect associated with cranes (or Ccr);
D——the permanent load effect;
Eo——the operational safety earthquake action effect;
Es——the ultimate safety earthquake action effect;
F——the fluid pressure effect, the equivalent earthquake action of equipment centroid;
{F}——the vector of horizontal earthquake action on the structure;
G——the total gravity load of equipment, the permanent load effect borne by foundation and base (including dead weight effect, fixed facility load effect and buoyancy effect);
H——the lateral earth pressure effect;
Ha——the load effect caused by internal overflow or external flooding of the structure;
L——the live load effect;
Lr——the live load effect on the roof;
M——the overturning moment caused by the combination of load on the base bottom;
Ma——the combined bending moment caused by dead weight and other continuous loads;
Mb——the sum of bending moments caused by operational safety ground motion and bending moments caused by other accidental loads;
Mi——the combined bending moments caused by mechanical load and earthquake action;
N——the load effect during normal operation and shutdown, the vertical force caused by combination of load on the base bottom;
P——the design value of compressive stress caused by Class D service load, design pressure and average compressive stress on the base bottom;
P0——the change amplitude of operating pressure;
Pa——the pressure load effect under design basis accident conditions;
Pmax——the peak pressure caused by Class B service load, the design value of maximum compressive stress at the edge of base bottom;
Pv——the external pressure load effect caused by internal or external pressure of
Contents
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
3.1 Principle of seismic conceptual design
3.2 Computation model
3.3 Computation methods of earthquake action
3.4 Floor response spectrum
3.5 Mechanical parameter of structures and materials
3.6 Combination for action effects and seismic checking
3.7 Aseismic measures
4 Design ground motions
4.1 General requirements
4.2 Parameters of design basis ground motion
4.3 Time histories of design ground motions
4.4 Ground motions at non-datum points
5 Foundation, base and slope
5.1 General requirements
5.2 Seismic checking for foundation and base
5.3 Seismic stability checking for slope
5.4 Determination of soil liquefaction
6 Containments, buildings and structures
6.1 General requirements
6.2 Effects of actions and their combinations
6.3 Seismic checking
7 Subterranean structures and subterranean pipes
7.1 General requirements
7.2 Earthquake actions of subterranean structures
7.3 Earthquake actions of subterranean pipes
7.4 Seismic checking
7.5 Aseismic measures
8 Equipments and components
8.1 General requirements
8.2 Earthquake actions and effects of the actions
8.3 Combination for action effects and limiting design value
9 Process pipes
9.1 General requirements
9.2 Earthquake actions and effects of the actions
9.3 Combination for action effects and limiting design value
9.4 Aseismic measures
9.5 Dampers
10 Earthquake monitoring and alarm
10.1 General requirements
10.2 Device configuration of the system
10.3 Device function and technical index
10.4 Maintenance and overhaul of devices
Annex A Analysis of foundation-structure interaction
Annex B Combination for maximum earthquake actions
Annex C Seismic response analysis of structure subjected to multiple inputs
Annex D Adjustment of design floor response spectrum
Annex E Reference method for performance-based seismic safety probability estimates
Annex F Normalized response spectra
Annex G Reference calculation method for target power spectral density
Annex H Combination for action effects and partial factors for buildings and structures
Annex J Quasi-static calculation methods for subterranean structures
Annex K Seismic evaluation tests for equipments
Annex L Allowable stress and limiting design value for equipments and components
Annex M Stress limit and stress index of process pipes
Explanation of wording in this standard
List of quoted standards
