ML22167A201
| ML22167A201 | |
| Person / Time | |
|---|---|
| Site: | Hermes File:Kairos Power icon.png |
| Issue date: | 06/16/2022 |
| From: | NRC |
| To: | NRC/NRR/DANU |
| References | |
| Download: ML22167A201 (5) | |
Text
From:
Colaccino, Joseph Sent:
Thursday, June 16, 2022 5:34 PM To:
Kennedy, William; Beasley, Benjamin Cc:
Lehman, Bryce
Subject:
Transmittal of Hermes CP SE Section 3.2 Attachments:
Hermes CP SE 3.2 - Lehman 6-10-22.docx
- All, Attached is the above referenced SE input from ESEB for this section. This email constitutes BC concurrence.
Please let me know if you have any questions.
Thanks, Joseph Colaccino Chief, Structural, Civil, and Geotechnical Engineering Branch (ESEB)
Division of Engineering and External Hazards Office of Nuclear Reactor Regulation Nuclear Regulatory Commission 301-415-7102 703-963-0133 (Mobile)
Hearing Identifier:
KairosPower_CPDocs_Public Email Number:
24 Mail Envelope Properties (DM8PR09MB7157CCCB9CC7DCDCBE64C5D999AC9)
Subject:
Transmittal of Hermes CP SE Section 3.2 Sent Date:
6/16/2022 5:34:27 PM Received Date:
6/16/2022 5:34:32 PM From:
Colaccino, Joseph Created By:
Joseph.Colaccino@nrc.gov Recipients:
"Lehman, Bryce" <Bryce.Lehman@nrc.gov>
Tracking Status: None "Kennedy, William" <William.Kennedy@nrc.gov>
Tracking Status: None "Beasley, Benjamin" <Benjamin.Beasley@nrc.gov>
Tracking Status: None Post Office:
DM8PR09MB7157.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 434 6/16/2022 5:34:32 PM Hermes CP SE 3.2 - Lehman 6-10-22.docx 42470 Options Priority:
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3 DESIGN OF STRUCTURES, SYSTEMS, AND COMPONENTS 3.2 Meteorological Damage Introduction Hermes PSAR Section 3.2 describes the approach used to translate site meteorological parameters (e.g., normal wind speed, precipitation) into design loads used in the design of the safety-related SSCs.
Section 3.2 summarizes the methods for determining wind loads, including loads from hurricanes and tornados, and precipitation loads, including snow and ice loads. Relevant consensus design codes and design equations are identified, along with relevant NRC guidance.
Regulatory Evaluation The applicable regulatory requirements for the evaluation of the Hermes SSCs for meteorological damage are as follows:
10 CFR 50.34, Contents of applications; technical information, paragraph (a), Preliminary safety analysis report.
o 10 CFR 50.34(a)(3)(iii) requires that each application for a construction permit include in the PSAR information relative to materials of construction, general arrangement, and approximate dimensions, sufficient to provide reasonable assurance that the final design will conform to the design bases with adequate margin for safety.
o 10 CFR 50.34(a)(4) requires, in part, that each application for a construction permit include in the PSAR a preliminary analysis and evaluation of the design and performance of structures, systems, and components of the facility with the objective of assessing the risk to public health and safety.
Guidance for this review includes:
NUREG-1537, Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors, Parts 1 and 2.
Appendix A to 10 CFR Part 50, General Design Criteria for Nuclear Power Plants, establishes minimum design requirements for water-cooled nuclear power plants similar in design and location to plants for which construction permits have been issued by the Commission. The General Design Criteria are also considered to be generally applicable to other types of nuclear power units and are intended to provide guidance in establishing the principal design criteria for such other units.
Technical Evaluation The staff evaluated the sufficiency of the facility design features to cope with meteorological damage, as described in PSAR Section 3.2, using the guidance and acceptance criteria from Section 3.2, Meteorological Damage, of NUREG-1537, Part 2. Consistent with the review procedures of NUREG-1537, Part 2, Section 3.2, the staff considered the description of the site meteorology to ensure that all SSCs that could suffer meteorological damage are considered, as presented in PSAR Sections 3.2, 3.5, and other relevant chapters of the PSAR. The staff also reviewed the design criteria to ensure they are compatible with local architectural and building codes for similar structures.
In its review of SSCs considered for meteorological damage, the staff noted that PSAR Section 3.2 describes the methodology and parameters used for determining the meteorological loads on the safety-
related portion of the reactor building. The structural loads are determined in accordance with ASCE/SEI 7-10, while tornado and hurricane wind speeds are taken from NRC Regulatory Guide (RG) 1.76 and RG 1.221, respectively. PSAR Section 3.2.4 notes that the final design will have a sloped roof, so structural loads due to rain accumulation are minimal and will be enveloped by the snow load.
During its review of Section 3.2, the staff noted that several subsections, equations, and associated variables from ASCE/SEI 7-10 were called out and explicitly defined in the PSAR. However, other relevant sections of the code (e.g., Sections 7.9 and 7.10) were not mentioned. The staff finds this approach acceptable for the construction permit because it is clear from PSAR Section 3.2 that the applicant intends to follow all applicable portions of ASCE/SEI 7-10. Many of the sections and variables that are not explicitly identified are dependent on the final structural design, such as roof height or slope.
Once this information is known, it can be incorporated into the FSAR, as necessary, and reviewed by the staff during the operating license review.
PSAR Section 3.2.3.2 notes that the maximum hurricane wind speed, V, is 130 miles per hour (mph), in accordance with RG 1.221. The Hermes site is located near Oak Ridge, TN in the northeastern portion of Roane County. The staff reviewed Figure 2 in RG 1.221 and noted that the Hermes location is below the 130-mph wind speed contour line and in the 140-mph zone. However, the proposed site is very close to the 130-mph line and the guidance in RG 1.221 notes that linear interpolation between two wind contour lines is permitted. If the maximum hurricane wind speed were increased by one or two mph (based on interpolation), it would have a negligible impact on the overall design of the structure; therefore, the staff finds it reasonable for 130-mph to be used as the hurricane wind speed.
During it review of PSAR Section 3.2.4.2, the staff noted that the ground snow load (pg) is identified as 10 pounds per square foot (psf) in Eq. 3.2-2, based on the guidance of Figure 7-1 in ASCE/SEI 7-10.
However, PSAR Section 2.3.1.11 notes that this value should be adjusted to 12.2 psf to account for a storm with a 100-year return period. The PSAR goes on to further state that using local historic snowfall records resulted in a snow load of 21.9 psf. Based on these different values, it was unclear to the staff if the appropriate value was being used in Eq. 3.2-2 to determine the roof snow load. The staff discussed this issue with the applicant during a public meeting on February 9, 2022 (ADAMS Accession No. ML22XXXX). Based on the discussion, the applicant submitted an updated PSAR by letter dated March 10, 2022 (ADAMS Accession No. ML22069B097). The update changed the value in Eq. 3.2-2 to 21.9 psf and noted that the value should align with the information provided in Section 2.3.1.11. The staff finds this acceptable because it aligns the snow load with the maximum expected snow load based on the analysis conducted in Section 2.3.1.11.
Based on the information provided in PSAR Section 3.2, the staff finds that the design, methodology and parameters used are, at a minimum, consistent with local applicable architectural and building codes for similar structures and are compatible with its functional requirements and capability to retain function throughout the predicted meteorological conditions.
Conclusion On the basis of its review, the staff has determined that the level of detail provided on meteorological damage is adequate for the preliminary design and supports the applicable acceptance criteria of NUREG-1537, Part 2, Section 3.2. The NRC staff concludes that the design criteria and design for the protection from meteorological damage conditions are based on applicable local building codes, standards, and criteria that provides assurance that SSCs will continue to perform their safety functions as specified in the PSAR. Therefore, the staff finds that the facility design features for coping with meteorological damage meet the applicable regulatory requirements for issuance of a construction permit in accordance with 10 CFR 50.35. Further technical or design information required to complete the safety analysis may reasonably be left for later consideration. The staff will confirm that the final Commented [LB1]: PM to provide ML# for 2/9/22 public meeting summary
design conforms to this design basis during the evaluation of the Hermes FSAR.
References
- 1. ASCE/SEI 7-10, Minimum Design Loads for Buildings and Other Structures, American Society of Civil Engineers, Reston, VA, March, 2013.
- 2. Regulatory Guide 1.76, Design-Basis Tornado and Tornado Missiles for Nuclear Power Plants (Revision 1), U.S. Nuclear Regulatory Commission, Washington, DC, March 2007, ADAMS Accession No. ML070360253.
- 3. Regulatory Guide 1.221, Design-Basis Hurricane and Hurricane Missiles for Nuclear Power Plants, U.S. Nuclear Regulatory Commission, Washington, DC, October 2011, ADAMS Accession No. ML110940300.