Content Ⅰ. Formation of seismic design code in Japan Ⅱ. Outline of Japan Nuclear Safety Committee’s

1. 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

2. 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 Technical support METI (Nuclear and Industrial SafetyAgency) ・Ministry Code No62“Technical code for Nuclear Power Reactor FacilitiesArticle5 Seismic requirement” (1 page) 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) Nowrevising

3. Formation of seismic design code in Japan NSCSeismic designReviewing Guide (Revised) 1.Introduction 2.Scope 3.Basic Policy 4.Classification of Importance in Seismic Design 5.Determination of design basis earthquake ground motion 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 JEAJEAG4601（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 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 ofequipment / piping system Load combinations and allowable limits, seismic force, response analysis, function maintenance evaluation, energy absorbing support NSCIntroduction to Safety Examination of Geology/Soil of NPP ( Not revised)

4. 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-tyuuetsu- oki earthquake and effect to Kashiwazaki NPP ・Upfill Ministry Code No62Article5 “Seismic requirement” Technical support JNES 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

5. Ⅱ. Outline of Japan Nuclear Safety Committee’s Seismic Design Review Guide; comparing Before and Revised

6. ◆ NSC revised Sep. 2006their“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

7. 1. Main points of the revision

8. 1.1 DBE Definition - Earthquake Research Flow Before （③） Considered Earthquakes（①） Past Earthquakes Basic Earthquake Ground Motion Ｓ1 Maximum Design Earthquake Active Faults Ground motion Evaluation Extreme Design Earthquake Basic Earthquake Ground Motion Ｓ2 Seismo-tectonic Features Near Field Earthquake （Horizontal componentonly） （②） （④） （②） Revised Design Earthquake Ground Motion Sd Considered Earthquakes（①） Inter-plate Earthquakes Ground motion Evaluation Site-specific Ground motionwith specified source Basic Earthquake Ground Motion Ss Shallow Inland Earthquakes Intra-plate Earthquakes （③） Both Horizontaland Vertical （④） Ground motion with non-specified source

9. DBE Definition - Earthquake Consideration Before ◆ Consider with each research methods Past Earthquakes ・Earthquake documents ・Active faults research ・Seismicity near site Active Faults Seismo-tectonic Features Revised ◆ Consider with each source type a.Inter-plate Earthquakes b.Shallow Inland Earthquakes c.Intra-plate Earthquakes

10. 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

11. DBE Definition – Near-Field Earthquake Before Consider Near-field Earthquake (M6.5) by way of precaution Revised 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

12. 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

13. 1.２ Geological Survey Revised Requirement for most updated technique and more detailed survey in the vicinity of the site In-land Seismic profiling by controlled seismic source Off-shore Supersonic wave survey ・Over 10km beneath the sea bottom can be searchable now Seismic Profiling

14. 1.3Consideration 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

15. 2. Seismic Classification Before 4 classes RPV, PCV etc. Ａs…Designed with Ｓ2 （Maintains Safety Function） ECCS, RHRS etc. also designed with Ｓ1 （Remains within Elastic limit） Main Turbine System etc. Ａ　…Designed with Ｓ1 Other Facilities （Remains within Elastic limit） Revised ◆ Ａ and As classes are integrated into S class 3 classes S…Designed with Ｓs （Maintains Safety Function） S also designed with Ｓd B （Remains within Elastic limit） C Sd＝α×Ss , α≧0.5

16. Before Aseismic classificationandseismicforce ★Total of four classifications of A, B, C class, and still more important As class. （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

17. Revised Total of three classifications of S, B, and C class. (Present As andA class were unified and it considered as S class.) It is changed into a higher rank from the present classification. REVISED

18. Before Load combination and allowable limit ★Load combination and allowable limit corresponding to four classifications

19. Revised ★Load combination and allowable limit corresponding to three classifications REVISED

20. 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 ★Followingsshould be taked into account in the seismic design • 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

21. Ⅲ. Comparison the point of seismic design practice between Japan and USAHere present Japan side

22. Outlines of Japanese Practice (Based on JEAG 4601) １． Load combinations and allowable stress limits Operating states and earthquakes are combined as above, considering probability of earthquakes and probability and duration of accidents.

23. Allowable Stress of Piping (Type 1) S1 (ⅢAS) , S2 (ⅣAS)

24. 2.１ Spectrum Modal Analysis Design FRS FRS 5. Making of FRS for Reasonable Evaluation of Components 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 4. Response Analysis of the Building 2. Design Base Earthquake 1. Target Spectrum of DBE

25. 2.1.1 Structures ◆Shear-Beam Modeling of Building ○Consolidates each mass of each facility and building structure to the floor Level ○Evaluate Stiffness of Column & Bearing-Wall against Bending-Moment & Shear Force

26. ◆Response Analysis of Building ○Modeling of Building ○Input Ground-Motion from Analysis of Soil ○Evaluate Response of Each Floor

27. Maximum Load Stress Collapse Linear Area Allowable Strain for Ss Limit Strain Shear Strain ・ Stress must be below allowable stress ・ Deformation must be below allowable deformation ・ Shear strain must be below allowable strain for Ss

28. Beam Element(Wall) Beam Element(Floor) Mass 質点 ◆Structures Model ■Mass-Stiffness Modeling ■FEM Modeling Beam Element (Wall) Mass Mass-Stiffness Model 3-D FEM Model

29. ◆Structures design result

30. ・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.

31. about 3 – 7 m ・Structures - Base mat The NPPs have strong foundation slabs 3 – 7 meters thick to withstand a great seismic force.

32. Response Acceleration (G) Own Proper Periods (s) 2.1.2 Piping Systems Dynamic Design Analysis of equipments based on their own proper periods Input RPV Allowable Stress ex. Allowable stress state ⅢAS ： 2.25Sm Allowable stress state ⅣAS ： 3Sm Evaluation Allowable Stress Response Stress <

33. ◆Design floor response spectrum, Damping Factor

34. Reactor Pressure Vessel (RPV) Separator RPV PCV Stabilizer Stabilizer Reactor Building Fuel Assembly Shroud Thermal Wall CRD Guide Tube CRD Housing Input DBE wave Diaphragm Floor Acceleration (Gal) Time (s) 2.2 Time Historical Analysisfor major facilities • Earthquake responses of some components around reactor are evaluated as a coupled system with the building and the ground.

35. ◆Piping and component supportdesign

36. 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 JNES NUPEC

37. 3.2 Example1 Concrete Containment Vessel Reinforced Concrete Containment Vessel (RCCV) scale : 1/10

38. Simulation Design Tests ◆Results(RCCV) increasing input motion gradually (from 2×S2) Results: ○RCCV was safe up to 5×S2. ○RCCV collapsed by shear force at 9×S2.

39. A: E: PERFORMANCE FOR ROTATION B:ELECTRICAL FUNCTION 2.2 Example 2 Seismic Fragility Tests C: D: C.R. INSERTION

40. ◆Data Example: Fragility of Electric Panels

41. Comparison the point of seismic design practice between Japan and USAHopingUSA side will be presented in near future

42. Ⅳ. Conclusion ・Research on Niigataken Tyustsu-Oki Earthquake July 2007is now on-going ・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