独立行政法人 原子力安全基盤機構 Content Ⅰ. Formation of seismic design code in Japan Ⅱ. Outline of Japan Nuclear Safety Committee’s Seismic Design Review Guide; comparing Before and Revised Ⅲ. Comparison the point of seismic design practice between Japan and USA Ⅳ.Conclusion 1 独立行政法人 原子力安全基盤機構 Ⅰ.Formation of seismic design code in Japan Nuclear Safety Commission ・Regulatory Guide for Reviewing Seismic Design of Nuclear Power Reactor Facilities (15pages) → 1981July Established 2006 Sept. Revised METI (Nuclear and Industrial Safety Agency) ・Ministry Code No62 “Technical code for Nuclear Power Reactor Facilities Article5 Seismic requirement” (1 page) Technical support JNES Endorse Japan Electric Association (Utilities) ・Technical Guidelines for Seismic Design of Nuclear Power Plants JEAG4601 (~1300pages) →1970,1984,1987,1991 Completed gradually (English version: NUREG/CR-6241) Now revising 2 独立行政法人 原子力安全基盤機構 Formation of seismic design code in Japan NSC Seismic design Reviewing Guide (Revised) 1.Introduction 2.Scope 3.Basic Policy 4.Classification of Importance in Seismic Design 5.Determination of design basis earthquake ground motion JEA JEAG4601 (Now under revising) 1.Basic items Purpose, Scope, Basic policy 2.Classification of Importance in Seismic Design Classification, seismic force for each class 3.Earthquake and basic earthquake ground motion for seismic design Earthquake ground motion, Tsunami evaluation 4.Geological and ground survey 6.Principle of seismic design Policy, Seismic force for each class 7.Load combinations and allowable limits 8.Consideration of the accompanying events of earthquake Tsunami, Collapse of inclined plane NSC Introduction to Safety Examination of Geology/Soil of NPP ( Not revised) 5.Safety evaluation of ground and seismic design of civil structures R/B base, around inclined plane, outside civil structures 6.Seismic design of building structures Material, load combinations and allowable limits, structural design, response analysis, seismic margin 7. Seismic design of equipment / piping system Load combinations and allowable limits, seismic force, response analysis, function maintenance evaluation, energy absorbing support 3 独立行政法人 原子力安全基盤機構 Each task for the present ; after NSC Guide revised NSC ・Review Seismic Re-evaluation of Existing NPPs by utilities ・Revise “Introduction to Safety Examination of Geology/Soil of NPPs” METI (NISA) ・Review Seismic Re-evaluation of Existing NPPs by utilities ・Investigate lessons learned from the Niigatakenn-tyuuetsuoki earthquake and effect to Kashiwazaki NPP Technical support JNES ・Upfill Ministry Code No62 Article5 “Seismic requirement” Utilities (Japan Electric Association ) ・ Seismic Re-evaluation of Existing NPPs according to revised NSC Guide ・ Review JEAG4601 according to lessons learned from the earthquake and re-evaluation of NPPs 4 独立行政法人 原子力安全基盤機構 Ⅱ. Outline of Japan Nuclear Safety Committee’s Seismic Design Review Guide; comparing Before and Revised 5 独立行政法人 原子力安全基盤機構 ◆ NSC revised Sep. 2006 their “Regulatory Guide for reviewing Seismic Design of Nuclear Power Reactor Facilities” , to reflect seismological and seismic engineering progress after 1995 Hyougo-ken Nanbu Earthquake. ◆ NISA promptly required utilities to re- evaluate seismic design of all existing NPPs according to revised guide. ◆ Utilities started re-evaluation from the step of geological survey 6 独立行政法人 原子力安全基盤機構 1. Main points of the revision Item Design Base Earthquake Definition Before ・S1: Return period more than 10000y Stay in elastic region* ・S2: Return period more than 50000y Keep function* * Class As、A component Geological Survey Consideration of Vertical Seismic Force Phenomena accompanying earthquake ・One DBE Ss: Consider active fault hereafter late Pleistocene (80000-130000y before) Keep function* ・Sd for design (Not earthquake) to stay in elastic region* Sd=α×Ss ; α≧0.5 * Class S component Use most updated knowledge and technique Fv= 1/2 FH (Static) Over DBE Earthquake Seismic Classification Revised Define Fv dynamically Possibility of over DBE earthquake cannot be denied. Risk by over DBE is to be assessed for reference As, A, B, C S (old As and A), B, C Old A class ranked up to As Consider the effect of; ・Tsunami, ・Collapse of around inclined plane 7 独立行政法人 原子力安全基盤機構 1.1 DBE Definition - Earthquake Research Flow (③) Before Past Earthquakes Maximum Design Earthquake Active Faults Extreme Design Earthquake Seismo-tectonic Features Near Field Earthquake (②) Revised Inter-plate Earthquakes Shallow Inland Earthquakes Intra-plate Earthquakes Basic Earthquake Ground Motion S1 Basic Earthquake Ground Motion S2 (Horizontal component only) (④) (②) Ground motion Evaluation Considered Earthquakes(①) Ground motion Evaluation Considered Earthquakes(①) Design Earthquake Ground Motion Sd Site-specific Ground motion with specified source Basic Earthquake Ground Motion Ss (③) Ground motion with non-specified source Both Horizontal and Vertical (④) 8 独立行政法人 原子力安全基盤機構 DBE Definition - Earthquake Consideration Before ◆ Consider with each research methods ・Earthquake documents ・Active faults research Past Earthquakes Active Faults ・Seismicity near site Seismo-tectonic Features Revised ◆ Consider with each source type a. Inter-plate Earthquakes b. Shallow Inland Earthquakes c. Intra-plate Earthquakes 9 独立行政法人 原子力安全基盤機構 DBE Definition – Ground Motion Evaluation Before ◆ Empirical methods (Response spectrum evaluation) Point source Revised ◆ Empirical methods + Strong motion evaluation using Earthquake source model Evaluate the Ground motion directly Consider the effects of the fault plane 10 独立行政法人 原子力安全基盤機構 DBE Definition – Near-Field Earthquake Consider Near-field Earthquake (M6.5) by way of precaution 擬似速度応答スペクトル(cm/s) Before 100 10 1 Revised 擬似速度応答スペクトル(cm/s) Estimate the upper level of the ground motion due to the earthquakes source of which are difficult to specify in spite of detailed survey in the vicinity of the site, directly on the basis of near-source strong motion records 0.01 0.1 周期(s) 1 10 1 10 100 10 1 0.01 0.1 周期(s) 11 独立行政法人 原子力安全基盤機構 Active Faults Consideration Before ◆ Consider the active faults that has activity in 50,000 years Active Fault of Low activity (Return period more than 50,000 ) → Consider as the source of S2 Active Fault of high activity (Return period more than 10,000 ) → Consider as the source of S1 Revised ◆ For Ss, consider the active faults that has activity in the late Pleistocene (referring to last Interglacial strata[about 80,000 – 130,000 years before]) Consider as the source of Inland Earthquakes for Ss 12 独立行政法人 1.2 Geological Survey 原子力安全基盤機構 Revised Requirement for most updated technique and more detailed survey in the vicinity of the site In-land Off-shore Seismic profiling by controlled seismic source Supersonic wave survey ・Over 10km beneath the sea bottom can be searchable now Seismic Profiling 13 独立行政法人 原子力安全基盤機構 1.3 Consideration of Vertical Seismic Force Before Consider Vertical Seismic Force as ½ as Horizontal, statically Dynamic Revised Consider Both Horizontal and Vertical Seismic Force dynamically Dynamic 14 独立行政法人 原子力安全基盤機構 2. Seismic Classification Before 4 classes RPV, PCV etc. As As … Designed with S2 A ECCS, RHRS etc. B Main Turbine System etc. C Other Facilities Revised 3 classes (Maintains Safety Function) also designed with S1 (Remains within Elastic limit) A … Designed with S1 (Remains within Elastic limit) ◆ A and As classes are integrated into S class S … Designed with Ss (Maintains Safety Function) S B C also designed with Sd (Remains within Elastic limit) Sd=α×Ss , α≧0.5 15 独立行政法人 原子力安全基盤機構 Before Aseismic classification and seismic force ★ Total of four classifications of A, B, C class, and still more important As class. PRESENT Seismic force Basic earthquake ground motion S2 Example of Major facilities Aseismic importance As Basic earthquake ground motion S1 or 3.0CI either large A Seismi force of 1.5CI (Note 5) B Seismi force of 1.0CI C BWR PWR ・Containment Vessel ・Control Rod ・Residual Heat Removal System ・Emergency Diesel Generator ・Reactor Pressure Vessel etc ・Containment Vessel ・Control Rod ・Residual Heat Removal System ・Emergency Diesel Generator ・Reactor Vessel etc ・Emergency Corel Cooling System etc ・Safety injecting System ・Waste Disposal System ・Turbine equipment(Note 5) etc ・Waste Disposal System etc etc ・Main Generator etc ・Main Generator ・Turbine equipment(Note 5) etc (Note 5)CI: Story shear coefficient to Static force required by civil code for non-nuclear structure (Note 6 ) Although turbine equipment is classified into C class according to a functional classification, turbine equipment of BWR is B class 16 独立行政法人 原子力安全基盤機構 Revised Total of three classifications of S, B, and C class. (Present As and A class were unified and it considered as S class.) It is changed into a higher rank from the present classification. REVISED REVISION Example of Major facilities Aseismic importance PWR BWR ・Containment Vessel ・Control Rod ・Residual Heat Removal System ・Emergency Diesel Generator ・Reactor Pressure Vessel etc ・Containment Vessel ・Control Rod ・Residual Heat Removal System ・Emergency Diesel Generator ・Reactor Vessel etc ・Emergency Corel Cooling System etc ・Safety injecting System ・Waste Disposal System ・Turbine equipment(Note 5) etc etc etc ・Horizontal sesmic force and vertica seismic force (dynamic)due to the basic earthguake ground motion Ss are combined both in the unfavorate direction ・Elastic design ground motion Sd or 3.0CI either large etc ・Waste Disposal System ・Main Generator S Seismic force ・Main Generator ・Turbine equipment(Note 5) B same as present C same as present etc 17 独立行政法人 原子力安全基盤機構 Before Load combination and allowable limit ★Load combination and allowable limit corresponding to four classifications PRESENT Allowable limit Load combination (1)Capability fully deformation (1)Basic earthquake ground (margin of ductility) as a structure motion S2 and normal load, and appropriate safety margin to etc ultimate strength (2)Either basic earthquake ground motion S1 or static (2)Allowable stress based on a load and normal load, etc suitable standard and standard Basic earthquake ground Allowable stress based on a motion S1 or static load and suitable standard and standard normal load, etc same as the above static load and normal load, etc same as the above same as the above (1)Even when the structure of a portion carries out plastic (1)Basic earthquake ground deformation fairly, excessive motion S2 and operating load,etc modification, a crack, breakage, etc. arise and the function of (2)Basic earthquake ground motion S1 or static load and facility is not affected. (2)Yield stress or the allowable limit operating load etc of equivalent safety Basic earthquake ground Yield stress or the allowable limit of motion S1 or static load and equivalent safety operating load, etc Allowable stress based on a Static load and operating suitable standard and standard load ,etc same as the above same as the above Aseismic importance Facilities As Building/ Structure A B C As Equipment/ piping A B C 18 独立行政法人 原子力安全基盤機構 Revised ★Load combination and allowable limit corresponding to three classifications REVISED REVISION Facilities Aseismic importance Load combination Allowable limit S (1)Basic earthquake ground motion Ss and normal load ,etc (2) Elastic design ground motion Sd or static load and normal load, etc same as present same as present same as present (1)Basic earthquake ground motion Ss and operating load, etc (2)Elastic design ground motion Sd or static load and operating load ,etc (1)Stress analysis is same as the present . (2) The check of active component to basic earthquake ground motion Ss is based on comparison with the acceleration using the actual probed examination ,etc same as present same as present Building/ Structure B C S Equipment/ piping B C 19 独立行政法人 原子力安全基盤機構 3.Consideration to the phenomena accompanying earthquake Before ★The concrete demand is not described The demand to the natural disaster of a landslide, tsunami or high tide, and others is specified independently. Revised ★Followings should be taked into account in the seismic design (1) Influence of the safety function on the facilities by collapse of a circumference slope (2) Influence of the safety function on the facilities by tsunami The maximum height of tsunami + The water level at the time of high water The minimum water level of tsunami ★Height of installation of plant ★Water proof design of facilities or equipment etc ★Management by the design of facilities or equipment etc 20 独立行政法人 原子力安全基盤機構 Ⅲ. Comparison the point of seismic design practice between Japan and USA Here present Japan side 21 独立行政法人 原子力安全基盤機構 Outlines of Japanese Practice (Based on JEAG 4601) 1. Load combinations and allowable stress limits Probability Operating States ( / year ) Earthquake ( / year ) Independent Event Combination with S1 Dependent Event S1 (Dependent) (Ex.) Taking into account of occurrence of S1 in the long term after LOCA 1min 1hour 1day 1year Operating states and earthquakes are combined as above, considering probability of earthquakes and probability and duration of accidents. 22 独立行政法人 原子力安全基盤機構 Allowable Stress of Piping (Type 1) Allowable stress state ⅢAS ⅣAS Stress Class Primary stress (including bending stress) Primary + Secondary stress Primary + Secondary + Peak stress 3 Sm Fatigue usage factor <= 1.0 2.25 Sm 3 Sm S1 (ⅢAS) , S2 (ⅣAS) 23 独立行政法人 原子力安全基盤機構 2.1 Spectrum Modal Analysis Design FRS 6. Dynamic Design Analysis of Components Based on their Own Proper Periods 3. Input the DBE into the Building, Taking into Account of the Ground 2. Design Base Earthquake FRS 5. Making of FRS for Reasonable Evaluation of Components 4. Response Analysis of the Building 1. Target Spectrum of DBE 24 独立行政法人 原子力安全基盤機構 2.1.1 Structures ◆ Shear-Beam Modeling of Building Mass Beam Model Floor Model ○ Consolidates each mass of each facility and building structure to the floor Level ○ Evaluate Stiffness of Column & Bearing-Wall against Bending-Moment & Shear Force 25 独立行政法人 原子力安全基盤機構 ◆ Response Analysis of Building ○ Modeling of Building ○ Input Ground-Motion from Analysis of Soil ○ Evaluate Response of Each Floor 26 独立行政法人 原子力安全基盤機構 ・ Stress must be below allowable stress ・ Deformation must be below allowable deformation ・ Shear strain must be below allowable strain for Ss Maximum Load Stress Collapse Linear Area Allowable Strain for Ss Limit Strain Shear Strain 27 独立行政法人 ◆ Structures Model 原子力安全基盤機構 ■ Mass-Stiffness Modeling ■ FEM Modeling Beam Element(Wall) Beam Element (Wall) Mass Beam Element(Floor) Mass 質点 Mass-Stiffness Model 3-D FEM Model 28 独立行政法人 原子力安全基盤機構 ◆ Structures design result Japan ・Occasionally, static force 3Ci * USA ? (for As,A Building) is dominant * 3 times larger than civil code for general structure 29 独立行政法人 原子力安全基盤機構 ・Structures - Wall The walls of NPPs’, arranged in a well-balanced manner, are about 10 times as thick as those of general buildings. Reinforcement have a far large diameter than that of general buildings, and is arranged more densely. 30 独立行政法人 原子力安全基盤機構 ・Structures - Base mat The NPPs have strong foundation slabs 3 – 7 meters thick to withstand a great seismic force. about 3 – 7 m 31 独立行政法人 原子力安全基盤機構 Response Acceleration (G) 2.1.2 Piping Systems Dynamic Design Analysis of equipments based on their own proper periods Input RPV Own Proper Periods (s) Allowable Stress ex. Allowable stress state ⅢAS : 2.25Sm Allowable stress state ⅣAS : 3Sm Evaluation Response Stress < Allowable Stress 32 独立行政法人 原子力安全基盤機構 ◆ Design floor response spectrum, Damping Factor Japan USA Design floor response spectrum: 10% Peak Broadening to absorb model or analysis uncertainty ? Damping Factor JEAG4601 ・piping 0.5~2.5 % ・welded structure 1.0 ・bolt, rivet fixture 2.0 ・ PCCV 3.0 ・reinforced concrete 5.0 RG1.61 ・variable according to stress level 33 独立行政法人 原子力安全基盤機構 2.2 Time Historical Analysis for major facilities PCV RPV Stabilizer Stabilizer Shroud Separator Thermal Wall Earthquake responses of some components around reactor are evaluated as a coupled system with the building and the ground. Fuel Assembly CRD Guide Tube CRD Housing Diaphragm Floor Acceleration (Gal) Reactor Building Reactor Pressure Vessel (RPV) Input DBE wave Time (s) 34 独立行政法人 原子力安全基盤機構 ◆ Piping and component support design Japan ・Support for hot piping and component; USA ・ Mechanical snubber or Oil snubber usually adopted Sticking problem resolved? ・ Energy absorbing support like Lead Damper will be adopted for APWR ( Code prepared and verification test finished) 35 独立行政法人 原子力安全基盤機構 3. Technical Expertise for Seismic Response of Facilities 3.1 Achievement of Tadotsu-Shaking Table 1980 1985 1990 1995 2000 2003 2006 Phase I (Proving Test of component) PCVs (PWR,BWR), RPVs (PWR,BWR), Core Internals (PWR,BWR), Primary Recirculation Loop (BWR), Primary Coolant Loop (PWR) Phase II (Proving Test of System Facilities) Emergency Diesel Generator System, Computer System, Reactor Shutdown Cooling System Phase III (New Design and Fragility) Main Steam & Feed Water piping with EBS, RCCV, PCCV, Steam Generator with EBS Seismic Tests for Regulation Fragility Test Series NUPEC JNES 36 独立行政法人 原子力安全基盤機構 3.2 Example1 Concrete Containment Vessel Reinforced Concrete Containment Vessel (RCCV) scale : 1/10 37 独立行政法人 原子力安全基盤機構 ◆ Results (RCCV) increasing input motion gradually (from 2×S2) Results: ○RCCV was safe up to 5×S2. ○RCCV collapsed by shear force Simulation Design Tests at 9×S2. 38 独立行政法人 2.2 Example 2 原子力安全基盤機構 Seismic Fragility Tests A:Horizontal Shaft Pump B:Electrical Panel C:Control Rod Insertion of PWR D:Control Rod Insertion of BWR E:Large Vertical Shaft Pump A: E: PERFORMANCE FOR ROTATION B:ELECTRICAL FUNCTION C: D: C.R. INSERTION 39 ◆ Data Example: Fragility of Electric Panels TEST PANELS Main Control Panel EVALUATION METHOD EXPERIMENT CRITICAL ACCELARATION INPUT ACCELARATION CRITICAL PARTS TEST RESULTS 2 (x9.8m/s ) (x9.8m/s2) 5.6 (S-S) display system 6 (S-S, F-B) No Malfunction Reactor Auxiliary Control Panel Logic Unit Panel 9.8 (F-B) module switch 6 (S-S, F-B) No Malfunction 6.7 (S-S) power unit 6 (S-S, F-B) No Malfunction Signal Processing Panel 4.4 (S-S) AC controller card 4.3 (S-S) Error of AC controller card 4.2 (S-S) differential pressure transmitter 6 (S-S, F-B) No Malfunction Instrumentation Rack Motor Control Center 4.5 (F-B) auxiliary relay 6 (F-B) Power Center 4.4 (F-B) air circuit breaker 5.0 (F-B) Metal-Clad Switchgear 4.2 (S-S) vacuum circuit breaker 4.7 (F-B) DIFFERENT TYPE PANELS Error of magnetic contactor caused by auxiliary relay chatter Damage of air circuit breaker Damage of vacuum circuit breaker CRITICAL ACCELARATION CRITICAL PARTS (x9.8m/s2) Logic Unit Panel 6.2 (S-S) Motor Control Center 7.1 (F-B) Power Center 4.3 (F-B) Metal-Clad Switchgear 4.0 (S-S) auxiliary relay molded case circuit breaker protection relay vacuum circuit breaker 40 40 Comparison the point of seismic design practice between Japan and USA Hoping USA side will be presented in near future 41 41 Ⅳ. Conclusion ・Research on Niigataken Tyustsu-Oki Earthquake July 2007is now ongoing ・This colloquium seems to be good occasion to present followings sequentially 1. Research output on the earthquake and influence to Kashiwazaki NPP 2. Lessons learned 3. Re- evaluation result of existing NPPs 4.How item 2 and 3 treated in Japanese seismic design code 42 42
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