ML18256A376
| ML18256A376 | |
| Person / Time | |
|---|---|
| Issue date: | 09/11/2018 |
| From: | Jose Pires Office of Nuclear Regulatory Research |
| To: | |
| Mehta S | |
| Shared Package | |
| ML18256A356 | List: |
| References | |
| Download: ML18256A376 (16) | |
Text
1 Codes and Standards for Structural and Seismic Safety: NESCC and the NRC Standards Forum Jose Pires Sr. Technical Advisor for Civil/Structural Engineering Division of Engineering NRC Office of Nuclear Regulatory Research Jose.Pires@nrc.gov 2018 NRC Standards Forum September 11, 2018
Activities / Products
- NESCC - Nuclear Energy Standards Coordination Collaborative (NIST/ANSI and NRC)
- 2009 to 2015
- (https://www.ansi.org/standards_activities/standards_boar ds_panels/nescc/overview?menuid=3)
- NRC Standards Forum
- Since 2016
- Timely identification, development, and revision of standards for the design, operation, development, licensing, and deployment of nuclear power plants 2
Activities / Products Concrete Codes and Standards for Nuclear Power Plants:
Recommendations for Future Development (June 2011) 3
- Issues on different design approaches used for containments and other safety-related structures (need to account for the different kind of safety functions expected)
- Issues on hierarchy of codes and dependencies - Seismic design provisions for example
- Harmonization with codes for other construction types like steel and composite structures: load combinations for example
Activities / Products Concrete Codes and Standards for Nuclear Power Plants:
Recommendations for Future Development (June 2011)
- Construction erection tolerances (liners and concrete)
- Specification for concrete material
- New technologies
- Types of reinforcement and high-strength steel reinforcement
- Anchorage of High-Strength Reinforcing Bars, David Darwin, University of Kansas, May 2015 4
Activities / Products Codes and Standards for the Repair of Nuclear Power Plant Concrete Structures: Recommendations for Future Development (September 2013)
- Inventory of related NRC documents
- Refers only to aging management documents (monitoring)
- Evaluation of a concrete structure
- Assessment of repair strategy and design
- Implementation of repair
- Monitoring and quality control 5
Steel and Steel Plate Plate Composite(SC) Structures -
AISC N690
- The Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition (NUREG-0800), 2010 (SRP), refers to:
- N690-1994 including Supplement 2 (2004)
- The Standard Review Plan for the Review of an Application for a Mixed Oxide (MOX) Fuel Fabrication Facility (NUREG-1718), 2000, refers to
- N690-1984 in Section 11.4.6.1 Regulatory Guidance 6
Steel and Steel Plate Composite (SC) Structures - AISC N690
- New reactors adopted modular SC structures as one of the major design features for some of their structures
- SC structures are used for the design of safety-related structures other than containment buildings
- Containment internal structures for example 7
Steel and Steel Plate Composite (SC) Structures - AISC N690
- The AISC started a multiyear effort to develop a standard for the design of SC structures
- In 2015, the AISC published the first U.S standard for the design of safety-related SC structures (Appendix N9 to the 2015 supplement of N690)
- The NESCC provided a forum to discuss the progress of the standard and of the NRC review 8
Steel and Steel Plate Composite (SC) Structures - AISC N690
- Review of the N690s1-2015 requires review of:
- AISC 360 (the N690 parent specification for the design of steel structures)
- Evolution of the design of safety-related structures from the Allowable Stress Design (ASD) approach in the N690-1994 and its 2014 supplement to
- The Allowable Strength Design (ASD) and Load and Resistance Factor Design approach (LRFD) in the current versions of N690
- The NRC review includes technical exchanges with AISC experts for clarifications and discussion of provisions in N690s1-2015 (for both steel and SC structures) 9
Steel and Steel Plate Composite (SC) Structures - AISC N690
- During the review process, the AISC updated N690 (for possible publication as N690-2018)
- The NRC plans to complete a draft regulatory guide with the staff position on N690 as follows
- Complete the N690 review using the most recent update of N690
- Conduct one additional technical exchange with AISC experts for further clarification of provisions
- Complete a draft regulatory guide (DG-1304) in the fourth quarter of FY19 10
Risk-informed Performance-Based (RIPB) Approach to Seismic Safety
- Earlier briefings to the NESCC on this topic
- Improving regulations governing the seismic safety of nuclear facilities, A. S. Whittaker (University at Buffalo) and R. J. Budnitz (LBNL), October 13, 2015 11
Risk-informed Performance-Based (RIPB) Approach to Seismic Safety 12 1971 1973 GDCs RG 1.60 Standardized seismic design response spectra 2005 ASCE 43-05 Establishes criteria for risk-informed performance-based seismic design (Reviewed in NUREG/CR-6926)
RG 1.208 Performance-based approach for selecting site-specific earthquake ground motion 2007 DOE 1020-2002 Natural Phenomena Hazards Analysis and Design Criteria for DOE Facilities (updated in 2012)
ASCE 43 Update (2018)
ASCE 4 Update (2016)
Seismic and structural analysis (consistent with ASCE 43)
ASCE 1 (Update) (2018)
Geotechnical analysis and design DOE and consensus standards 1996 2016-2021
> 2021 RG 1.208 Update New RGs Performance-based seismic design criteria and analysis SRP Revisions Advanced Reactors Performance-based guidance Other hazards 10CFR100.23 Requires addressing uncertainties in SSE estimates and permits use of PSHA 10CFR50 App. S Relocated seismic engineering design criteria in Part 50 RG 1.165 PSHA guidance 2002 Evolution towards a RIPB approach
- Design basis ground motions for new reactors are based on ASCE 43 approach (Regulatory Guidance 1.208)
- The performance target for new reactors is at the plant level vs. component level target in ASCE 43 (ISG-DC/COL-20) 13 Current Status of Risk-Informed Performance-Based Design
Research Aspects Next steps in the development of risk-informed performance-based approaches to seismic safety
- Technical basis for the update of Regulatory Guide 1.208
- Bridging the gap between Regulatory Guide 1.208 and an integrated, performance-based approach to seismic/structural analysis and design of SSCs important to safety
- Technical basis to update/develop staff positions on recent and forthcoming updates of standards for performance-based seismic analysis and design of structures and components in nuclear installations (ASCE 4-16, ASCE 43 and ASCE 1, for example)
- Integration with other hazards Future direction to pursue possibilities outlined in NUREG/CR-7214 14 Risk-informed Performance-Based (RIPB) Approach to Seismic Safety
Future Direction - Broader Integrated Approach (NUREG/CR-7214)
NUREG/CR-7214, Toward a More Risk-Informed and Performance-Based Framework for the Regulation of the Seismic Safety of Nuclear Power Plants, R.
Budnitz and M. Mieler, Lawrence Berkeley National Laboratory, May 2016.
https://www.nrc.gov/docs/ML1612/ML16126A008.pdf 15 Perform a Design Perform a Seismic PRA Identify major accident sequences Identify importance of each SSC Identify design solutions using risk categorization Provide more margin where needed (and that backs off as appropriate)
ASCE 43 provides a framework of performance goals at SSC level Similar to the concept of design basis sequence in addition to postulated design basis accidents Choose figures of merit Maintain defense in depth and other qualitative factors such as balance between prevention and mitigation and over reliance on human actions
American Institute of Steel Construction ANSI -
American National Standards Institute ASCE -
American Society of Civil Engineers ASD -
Allowable Stress Design DOE -
Department of Energy LBNL -
Lawrence Berkeley National Laboratory LRFD -
Load and Resistance Factor Design PRA -
Probabilistic Risk Assessment NRC -
Nuclear Regulatory Commission SC -
Modular Composite Construction (Wall modules constructed from large prefabricated sections of steel plates spaced apart and joined with intermittent steel members or tie bars, joined with other modules at the site, and then filled with concrete)
SSC -
Structures, Systems and Components SRP -
Standard Review Plan 16