Jan-Anders Larsson Scanscot Technology AB. Design Guide for Nuclear Civil Structures Dimensionering av nukleära byggnadskonstruktioner (DNB)

Transcription

1 Jan-Anders Larsson Scanscot Technology AB Design Guide for Nuclear Civil Structures Dimensionering av nukleära byggnadskonstruktioner ()

2 GUIDE FOR NUCLEAR CIVIL STRUCTURES - NEW GUIDE Design Guidance for safety-related concrete structures at NPPs, including the reactor containment. Based on Eurocodes, i.e. the European Code for design of civil structures. is established on behalf of the Swedish Radition Safety Authority (SSM) and the Swedish Licensees. Written by a project team at Scanscot Technology AB. Issued by SSM as an R&D report.

3 ORIGINAL PLANT IN SWEDEN CIVIL STRUCTURES BACK- GROUND The design and construction of the commercial NPPs in Sweden were carried out over a period of ~20 years. Placing of first order 1965 (Oskarshamn Unit 1) The latest plant connected to the grid 1985 (Oskarshamn Unit 3) All-in-all 12 commercial nuclear power reactors were constructed. 9 BWRs (Asea-Atom, three different generations) 3 PWRs (Westinghouse) Situated at four different sites 10 units at 3 sites still in operation

4 ORIGINAL PLANT IN SWEDEN CIVIL STRUCTURES BACK- GROUND The design and construction of the commercial NPPs in Sweden were carried out over a period of ~20 years. Placing of first order 1965 (Oskarshamn Unit 1) The latest plant connected to the grid 1985 (Oskarshamn Unit 3) All-in-all 12 commercial nuclear power reactors were constructed. 9 BWRs (Asea-Atom, three different generations) 3 PWRs (Westinghouse) Situated at four different sites 10 units at 3 sites still in operation A DIFFICULT MIXTURE OF DIFFERENT REACTOR TYPES, PRINCIPLES AND CODES!

5 BACK- GROUND HARMONIZATION OF RULES FOR CIVIL STRUCTURES In the BOKA-project during the 1990s, harmonizing the design rules for all Civil structures was identified as a safety-critical issue. Scanscot Technology was engaged to develop DRB, design rules based on the at that time Swedish Building Codes in force. In 2011, the Swedish Building Codes were replaced by the Eurocodes. SSM and the Licensees assigned Scanscot Technology to develop the Design Guide for Nuclear Civil Structures (), based on Eurocodes. RULES FOR BUILDINGS AT NUCLEAR FACILITIES, DRB FIRST EDITION 1998 UPDATED 2001 GUIDE FOR NUCLEAR CIVIL STRUCTURES, FIRST EDITION 2014

6 BACK- GROUND - PROJECT ORGANIZATION STEERING COMMITTEE Swedish Radiation Safety Authority (SSM) Swedish Licensees (OKG, RAB, FKAB, SKB) PROJECT TEAM Scanscot Technology Author of the report Prof. S. Thelandersson Lund University Reviewer EVALUATION OF THE REPORT Selected stakeholders Review and comments Steering Committee Review & final acceptance of the report Forsmark Kraftgrupp AB Ringhals AB

7 TABLE OF CONTENT SCOPE 1. Introduction 2. General conditions 3. Basic principles of structural design 4. Actions and combinations of actions 5. Design of the reactor containment 6. Design of other concrete structures 7. Seismic design 8. Design related to the construction phase 9. References General applicable (with some limitations) Concrete structures General applicable (with some limitations) Appendix 1 8: Summaries, explanations and additional information

8 Swedish laws and regulations GENERAL PRINCIPLES GENERAL PRINCIPLES IAEA safety requirements for NPPs IAEA NS-G-1.10 acceptance criteria for reactor containments The Act on Nuclear Activities etc. Swedish Radiation Safety Authority s Regulations and general advice Planning and Building Act Swedish National Board of Housing, Building and Planning: National Annex to Eurocodes Eurocodes with belonging standards Nuclear specific add on rules Codes & Standards for NPPs Add on rules according to Swedish conditions

9 Swedish laws and regulations Swedish Nuclear Regulations The Act on Nuclear Activities etc. Planning and Building Act GENERAL PRINCIPLES IAEA safety requirements for NPPs IAEA NS-G-1.10 acceptance criteria for reactor containments Swedish Radiation Safety Authority s Regulations and general advice Swedish National Board of Housing, Building and Planning: National Annex to Eurocodes Eurocodes with belonging standards Nuclear specific add on rules Codes & Standards for NPPs Add on rules according to Swedish conditions

10 Swedish laws and regulations Swedish Building Regulations The Act on Nuclear Activities etc. Planning and Building Act GENERAL PRINCIPLES IAEA safety requirements for NPPs IAEA NS-G-1.10 acceptance criteria for reactor containments Swedish Radiation Safety Authority s Regulations and general advice Swedish National Board of Housing, Building and Planning: National Annex to Eurocodes Eurocodes with belonging standards Nuclear specific add on rules Codes & Standards for NPPs Add on rules according to Swedish conditions

11 Swedish laws and regulations IAEA safety requirements The Act on Nuclear Activities etc. Planning and Building Act GENERAL PRINCIPLES IAEA safety requirements for NPPs IAEA NS-G-1.10 acceptance criteria for reactor containments Swedish Radiation Safety Authority s Regulations and general advice Swedish National Board of Housing, Building and Planning: National Annex to Eurocodes Eurocodes with belonging standards Nuclear specific add on rules Codes & Standards for NPPs Add on rules according to Swedish conditions

12 GENERAL PRINCIPLES - GENERAL PRINCIPLES IAEA specifies general safety requirements for Nuclear Power Plants. These requirements are normally adopted by National Safety Radiation Authorities. IAEA specifies in NS-G-1.10 general acceptance criteria for the behavior of the reactor containment related to structural integrity and leak-tightness. These general acceptance criteria are in agreement with the overall safety requirements. complies with the IAEA NS-G-1.10 general acceptance criteria for the reactor containment. IAEA Safety requirements IAEA NS-G-1.10 General accepctance criteria for structural integrity and leaktightness of the containment Design Guide for Nuclear Civil Structures Eurocodes ASME Sect III Div 2

13 IAEA NS-G GENERAL ACCEPTANCE CRITERIA GENERAL PRINCIPLES CONTAINMENT BEHAVIOR Structural integrity Level I: Elastic range Level II: Small permanent deformations Level III: Large permanent deformations Leak-tightness Level I: Leak-tight structure Level II: Limited increase of leak rate Level III: Large or very large increase of leak rate Acceptance criteria specified for major load combinations

14 GENERAL PRINCIPLES IAEA Load Combinations

15 GENERAL PRINCIPLES IAEA Acceptance Criteria

16 THE GENERAL APPROACH IN APPROACH EUROCODES The basic design code is Eurocodes for all Civil structures. ADD ON RULES Eurocodes cover conventional facilities. Nuclear specific amendments, modifications and limitations have been added in ( add on rules ). The add on rules are based on Swedish legislation, regulations and design practice, and through study of internationally established Codes & Standards, Guidelines, IAEA Standards and WENRA Reports. REFERENCE TO OTHER CODES For some especially important topics, internationally accepted documents have been incorporated more or less completely by reference, together with adjustments due to Swedish conditions. It has not been the intention to establish completely unique Swedish add on rules, for instance based on evaluation of available research results, additional testing and so on.

17 THE GENERAL APPROACH IN BASIC CODE Eurocodes and NA 1) ADD ON RULES Nuclear specific amendments, modifications and limitations APPROACH SEISMIC (REPLACES EC8) REACTOR CONTAINMENT (IN ADDITION TO EC) ASCE ) ASME SECT III DIV 2 3) Amendments, modifications and limitation due to Swedish conditions 1) Swedish National Annexes for Buildings: Boverket, BFS 2011:10 EKS 8 Boverkets föreskrifter och allmänna råd om tillämpning av europeiska konstruktionsstandarder (eurokoder) 2) ASCE 4-98 Seismic Analysis of Safety-Related Nuclear Structures and Commentary 3) ASME Sect III Div 2 Code for Concrete Containments

18 MOTIVATION TO ADOPT ASCE 4-98 APPROACH This Code is internationally accepted for seismic analysis of safetyrelated nuclear structures. Since ASCE 4-98 is written specifically for nuclear facilities it provides more stringent and comprehensive seismic design rules than EC8. The requirements in ASCE 4-98 are Code neutral and could therefore be adopted. ASCE 4-98 is accepted by USNRC (except when later RGs and SRPs overrules). The same principles are stated in. Can take advantage of future updates of the document. ASCE 4-98 already part of SAR for some Swedish units.

19 MOTIVATION TO ADOPT ASME SECT III DIV 2 APPROACH Internationally established and adopted in the US and Asia and in Europe in many of the ongoing or planned New Build projects. The Eurocodes do not address containment leak-tightness requirements for a steel liner. The ASME Code does. Finnish YVL Guide E.6 states that for the concrete structures EC2 should be followed with ASME as minimum requirement. The steel liner should be designed according to ASME. This code is general and covers prestressed as well as non-prestressed containments. It provides very detailed design guidance. Due to the fact that the code is internationally established, it can easier be accepted by Swedish stakeholders and safety authorities and the society in general.

20 MOTIVATION TO ADOPT ASME SECT III DIV 2 APPROACH Mechanical safety systems at the Swedish plants are normally designed with the same Code package as proposed for the reactor containment; ASME B & PV Code Section III. ASME has been applied for the design of the reactor containments Forsmark 3 and Oskarshamn 3. US requirements are traditionally used in Sweden. The SARs for several Swedish NPP units refer to Appendix A of 10 CFR Part 50, which amongst other things covers the general demands for the reactor containment. ASME Sect III Div 2 is accepted by USNRC to be used to prove that relevant parts of App. A of 10 CFR Part 50 are fulfilled. You can take advantage of the future developments of ASME.

21 MOTIVATION TO ADOPT ASME SECT III DIV 2 Facilitate the implementation of available NPP layouts. Many Vendors in the nuclear industry have New Build basic design layouts which comply with the standards adopted in (ASME Sect III Div 2 and ASCE 4-98). This facilitates to some extent an eventual future implementation in Sweden.

22 DEALING WITH DISADVANTAGES APPROACH Different basic design approaches Eurocodes and ASME Sect III Div 2 have different design approaches, i.e. limit state + partial factors vs. allowable stresses. ASME has therefore been implemented in in such a way that in practice two separate design calculations are carried out, one in accordance with Eurocodes and one in accordance with ASME. The most conservative outcome has to be applied. Refers to US material and testing standards A separate investigation has been applied by comparison of testing standards in ASME and Eurocodes, in order to use European standards through conversion factors.

23 GUIDE FOR NUCLEAR CIVIL STRUCTURES () First edition finalized 2013 (issued January 2014) General requirements and design provisions Loads and load combinations Design of concrete structures Seismic design DEVELOP- MENT

24 GUIDE FOR NUCLEAR CIVIL STRUCTURES () DEVELOP- MENT First edition finalized 2013 (issued January 2014) General requirements and design provisions Loads and load combinations Design of concrete structures Seismic design Second edition finalized 2014 (to be issued) General updates Guidance for in-situ material testing to determine concrete strength English translation

25 GUIDE FOR NUCLEAR CIVIL STRUCTURES () DEVELOP- MENT First edition finalized 2013 (issued January 2014) General requirements and design provisions Loads and load combinations Design of concrete structures Seismic design Second edition finalized 2014 (to be issued) General updates Guidance for in-situ material testing to determine concrete strength English translation Planned work for 2015 (TBD) Fire design Missile impact and impulsive loading

26 THANK YOU FOR YOUR ATTENTION! NEW BUILD POWER UPRATE STRESS TESTS RESEARCH FACILITIES