TVA Clinch River Project. Early Site Permit Application. Plant Parameter Envelope Methodology

Transcription

1 TVA Clinch River Project Early Site Permit Application Plant Parameter Envelope Methodology September 11, 2014

2 Agenda Introductions Project and Site Overview Plant Parameter Envelope (PPE) Methodology Early Site Permit (ESP) and PPE Guidance Basis NEI and Small Modular Reactor (SMR) Vendor Information Requests PPE Information Use and Examples Configuration Control of PPE Summary and Questions Slide 2

3 Purpose Update NRC on TVA Clinch River Project Status Discuss TVA s methodology for developing the PPE values to be used in preparation of an ESP application Obtain NRC feedback on TVA s planned PPE methodology Focus is on discussion of methodology, not values Slide 3

4 Project Background - History TVA has worked with NRC since late 2010 on Clinch River Project Activities Original plan was to submit a Construction Permit Application under 10 CFR Part 50 in conjunction with a B&W mpower TM Design Certification Application (DCA) B&W mpower has delayed their planned DCA submittal TVA has been evaluating impacts and options and remains committed to develop an SMR option Slide 4

5 Project Go Forward Plans TVA has decided to pursue a 10 CFR Part 52 regulatory approach TVA intends to prepare an ESP Application (ESPA) for potential U.S. light-water reactor SMR deployment at the Clinch River Site using a PPE TVA plans to submit the ESPA in the Fall of 2015 Submittal of a Construction and Operation License Application (COLA) is subject to a TVA decision to proceed and will follow the submittal of one or more DCAs to the NRC. Slide 5

6 Why an ESP? An ESP is an asset. It addresses site safety, environmental protection, and emergency preparedness issues and is valid for 10 to 20 years Most of the work done to date at the Clinch River Site is directly applicable to an ESP application An ESP approach lowers future COLA costs & risks It is a step that TVA can take in the near term while SMR vendors continue developing their designs and prepare their Design Certification Applications Slide 6

7 Clinch River Site Attractive Site Features: Access to 500 KV and 161 KV transmission Neighbor to DOE, an interested customer Basic Infrastructure Abundant and skilled workforce Strong community support TVA owned/controlled Slide 7

8 Project Background - Site Characterization Completed Work: Core Borings Ground Water Well Installation Meteorological data collection Biological Surveys Botany Surveys Wetland Surveys Cultural Resource Surveys Slide 8

9 Project Background - Site Characterization Ongoing Work: Groundwater Analysis Hydrothermal Analysis Flood Analysis Seismic Analysis Slide 9

10 ESP Application Development Guidance Slide 10 Bound U.S. Light Water Reactor SMR designs in the PPE Follows the guidance of: NEI Revision 1, Industry Guideline for Developing a Plant Parameter Envelope in support of an Early Site Permit - NRC Review Standard (RS)-002, Processing Applications for Early Site Permits - NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants - NUREG-1555, Standard Review Plans for Environmental Reviews for Nuclear Power Plants - Interim Staff Guidance (ISG), COL/ESP ISG 026, Environmental Issues Associated with New Reactors and COL/ESP ISG 027, Specific Environmental Guidance for Light Water Small Modular Reactor Reviews Goal is to use best available industry guidance

11 PPE Methodology Slide 11 from NEI 10-01

12 PPE Methodology - Key Terminology (1/2) Site Information - physical description of the postulated features of a specific site that is used, in combination with vendor information, to develop Owner/Engineered Parameters Site Characteristics - actual physical, environmental and demographic features of a specific site that are specified in the ESP Site Parameters - reactor specific by vendor, independent of a particular site and represent postulated physical, environmental, and demographic features of an assumed site that is utilized as a basis for the design analysis Slide 12

13 PPE Methodology - Key Terminology (2/2) Owner/Engineered Parameters - postulated features of a reactor or reactors that could be built at a specific site that are derived from a combination of vendor and site information Reactor Parameters - postulated features of a reactor or reactors that could be built at a proposed site (same as design parameters in 10 CFR Part 52.1(a)) Slide 13

14 PPE Methodology Worksheets Excerpt from NEI Vendor Worksheet, Appendix B, Table 1 PPE Section Definition Technology Supplier Value SW Heat Exchanger Duty The heat transferred to the nonsafety related service water system for rejection to the environment. 3.3 Mechanical Draft Cooling Towers Acreage The land required for cooling towers, including support facilities such as equipment sheds, basins, canals, or shoreline buffer areas Approach Temperature The difference between the cold water temperature and the ambient wet bulb temperature. 10. Liquid Radwaste System Notes/ Comments Parameter Type Rx Eng Eng SSAR Applicability ER X X X 10.1 Dose Consequences Normal The estimated design radiological dose consequences due to liquid effluent releases from normal operation of the plant Post-Accident The estimated design radiological dose consequences due to liquid effluent releases from postulated accidents. Vendor worksheets used for technical data collection Site X X Site X X Slide 14

15 Vendor Information Requests (1/2) Additional information was requested to assess design and regulatory readiness Assess technical and regulatory progress Gain better understanding of technology and risk areas Assess progress toward resolution of risks Provides insight towards amount of margin TVA should apply to parameters Slide 15

16 Vendor Information Requests (2/2) Appropriate due diligence was exercised by TVA to assure vendor input was understood Focus areas for assessment of vendor input Degree of design completion Vendor margin included Uniqueness of SMR design Goal was appropriate assignment of margin to establish reasonable PPE values Slide 16

17 PPE Information Use (1/2) Site Safety Analysis Report (SSAR) Primarily General Design Basis Parameters o Seismic, wind, flooding levels, ambient conditions, etc. o Thermal output, height, embedment depth, etc. General Structure Layout o Acreage, buildings Radioactive Releases o Expected normal release parameters (gaseous, liquid, solid) o Accident release parameters: Atmospheric dispersion characteristics (X/Q) Source terms Postulated accidents Slide 17

18 PPE Information Use (2/2) Environmental Report (ER) Heat Dissipation and Water Usage Parameters o Water intake and output parameters o Cooling tower and condenser parameters o Heat rejection (ponding, ambient air, etc.) Nuclear Fuel Usage o Amount and characteristics of fuel usage o Spent fuel storage parameters Other Site Fuel Parameters (e.g., Diesel) o Storage and exhaust Slide 18

19 PPE Methodology Vendor data evaluated for bounding values Regulatory guidance reviewed for specific requirements How the parameters were used in the ER and SSAR was considered when determining reasonable PPE values Assignment of reasonable margin considered: Completeness of design and potential for change Margin inherent in other elements affecting parameter Three examples will be presented to illustrate process used in setting bounding PPE values and site characteristics values Slide 19

20 Example Site Characteristics Maximum Pressure Drop Definition: The design assumption for the decrease in ambient pressure from normal atmospheric pressure due to the passage of the tornado. Environmental Report: Not applicable Site Safety Analysis Report: Plant must be designed to remain in a safe condition for most severe tornado conditions. Regulatory Guide (RG) 1.76 indicates that a maximum pressure drop of 1.2 psi is appropriate for tornadoes in central portion of the United States (Region I). Vendor Parameter: The maximum differential pressure used to ensure structural integrity due to passage of a postulated tornado. Vendor 1 Value: 1.2 psi Vendor 2 Value: 1.2 psi Vendor 3 Value: 1.2 psi Vendor 4 Value: 2.0 psi Site Value: Site value is 1.2 psi (from RG 1.76 for location of Clinch River site) PPE Value: TVA selected a value of 1.2 psi because it is the appropriate value for tornadoes in central portion of the United States (Region I) and bounds all vendor values Margin: No margin added to parameter (RG method establishes adequate margin) Example of regulatory guidance used Slide 20

21 Example Engineered Parameter Blowdown Flow Rate Definition: Normal flow rate of the blowdown stream from the cooling water systems to the receiving water body for closed system designs. Environmental Report: A description of the plant water usage and consumption parameters is needed to evaluate the exit water temperature and volumetric flow. Site Safety Analysis Report: Not Applicable Vendor Parameter: This value is used as the postulated high expected blowdown flow rate and provides the highest impact on the ambient river temperature. Vendor 1 Value: 3,540 gpm/site (4 cycles of concentration) Vendor 2 Value: TBD Vendor 3 Value: 4,678 gpm/site (3 cycles of concentration) Vendor 4 Value: 3,930 gpm/site (4 cycles of concentration) Slide 21

22 Example Engineered Parameter Blowdown Flow Rate (continued) Site Value: No specific site value is needed for this parameter PPE Value: Vendor condenser/cooling tower designs are not complete. Some vendors may optimize thermal output between now and their DCA submittal. TVA normalized the values to 4 cycles of concentration, which resulted in a value of 3,130 gpm/site for Vendor 3, and added additional margin for potential design changes. TVA selected 4,270 gpm based on 4 cycles of concentration which contains adequate margin. Margin: Adequate margin is included as described above for the four proposed designs Example of wide range of input that required TVA analysis Slide 22

23 Example Reactor Parameter Height (without Stack and Cooling Towers) Definition: Height from finished grade to the top of the tallest power block structure, excluding stack and cooling towers Environmental Report: Maximum height is used to evaluate impacts (building aesthetics, aircraft visibility, etc.) Site Safety Analysis Report: Minimum height is used to evaluate radioactive effluent release points and building wake effects for atmospheric dispersions Vendor Parameter: Both minimum and maximum value used in plant design Vendor 1 Value: 115 feet Vendor 2 Value: 115 feet Vendor 3 Value: 81 feet Vendor 4 Value: feet Site Value: No site value for this parameter. PPE Value: Maximum vendor value is 115 feet. Additional margin of 45 feet is included for potential plant design changes. Maximum PPE value is 160 feet. Ground level (zero feet) used conservatively as a minimum value in SSAR calculations. Margin: Discretionary margin of 45 feet is added to the vendor maximum value and 81 feet removed for a minimum value for simplification and design uncertainty Example of added margin in bounding value Slide 23

24 Fuel-Related Parameters Fuel-related parameters are used in both the ER and the SSAR ER to use individual bounding parameters from steady state operations SSAR to use vendor data set to calculate accident analysis inputs Because TVA expects no DCA will have been submitted at ESPA submittal, TVA intends to use bounding vendor data sets in the SSAR Example of vendor sets for bounding values Slide 24

25 PPE Configuration Control The PPE table containing values and worksheets will be issued in a controlled document for internal use in the ESP application development PPE values will be reviewed when the site characterization work is complete for any necessary updates PPE values will be reviewed for consistency when used in multiple places in the ESP application PPE values will be reviewed by the vendors and may be updated based on vendor feedback Slide 25

26 Summary and Questions TVA is preparing an ESPA for the Clinch River site for planned submittal in the Fall of 2015 TVA assumes NRC will receive the ESPA before DCAs from any SMR vendor ESPA will use a PPE developed based on input from four US LWR SMR vendors using best available industry guidance This approach provides reasonable PPE values using a structured approach with margins applied Questions? Slide 26