ML24078A337
| ML24078A337 | |
| Person / Time | |
|---|---|
| Site: | 99902056 |
| Issue date: | 03/18/2024 |
| From: | NRC |
| To: | NRC/NRR/DNRL |
| References | |
| Download: ML24078A337 (9) | |
Text
From:
Sean Gallagher Sent:
Monday, March 18, 2024 2:12 PM To:
Schiele, Raymond Joseph Cc:
Allen Fetter; Greg Cranston; ClinchRiver-CPSafDocsPEm Resource
Subject:
TVA CRNS Readiness Assessment Phase 3 Initial PSAR Observations Attachments:
TVA CRNS Readiness Assessment Phase 3 (3.7, 3.8, 9.1, 9.2) Initial Observations.pdf Good Afternoon, Attached are initial NRC staff observations on draft PSAR Sections 3.7, 3.8, 9.1, and 9.2 that staff viewed in TVAs electronic reading room as part of Phase 3 of the Readiness Assessment of the draft Clinch River CP application.
After all six phases of the Readiness Assessment are completed, NRC will transmit, via letter, a compilation of all final Readiness Observations on the Clinch River CP PSAR chapters and sections. The nomenclature initial is being used to account for potential TVA updates to the PSAR before the end of the Readiness Assessment.
If TVA makes any future updates to the draft PSAR chapters and sections for follow up observations by NRC staff, please contact myself, Greg Cranston or Allen Fetter.
- Thanks,
- Regards, Sean Gallagher, Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of New and Renewed Licenses New Reactor Licensing and Infrastructure Branch Washington, D.C.
Hearing Identifier:
ClinchRiver_CPSafDocs_Public Email Number:
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Subject:
TVA CRNS Readiness Assessment Phase 3 Initial PSAR Observations Sent Date:
3/18/2024 2:11:55 PM Received Date:
3/18/2024 2:11:58 PM From:
Sean Gallagher Created By:
Sean.Gallagher@nrc.gov Recipients:
"Allen Fetter" <Allen.Fetter@nrc.gov>
Tracking Status: None "Greg Cranston" <Gregory.Cranston@nrc.gov>
Tracking Status: None "ClinchRiver-CPSafDocsPEm Resource" <ClinchRiver-CPSafDocsPEm.Resource@nrc.gov>
Tracking Status: None "Schiele, Raymond Joseph" <rjschiele@tva.gov>
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SA9PR09MB5533.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 1032 3/18/2024 2:11:58 PM TVA CRNS Readiness Assessment Phase 3 (3.7, 3.8, 9.1, 9.2) Initial Observations.pdf 181342 Options Priority:
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Readiness Assessment - Phase 3 1
Clinch River Nuclear Site Unit 1 BWRX-300 Preliminary Safety Analysis Report March 7, 2024 Chapter/Section 3.7 Section Basis for Observation/Comment Readiness Assessment Observations/Comments 3.7.1.1.2 - Design Time Histories Technical judgment While it is stated in this section "time histories compatible to the bounding design ground motion spectra in Figure 3.7-2 are generated using the time domain spectral matching method,", the PSAR should reference the published documents (papers, reports, etc.) that this method is based upon.
3.7.1.1.2 - Design Time Histories NUREG-0800 Section 3.7.1.II.1.B, states "For generated time histories, it should be demonstrated that acceleration, velocity, and displacement are compatible and do not result in displacements baseline drift."
The PSAR does not include the modified Time Histories (TH), acceleration, velocity, and displacement plots to demonstrate there is no displacement baseline drift.
3.7.1.3 - Supporting Media for Seismic Category I Structures 10 CFR 50.34(a)(3)(iii),
states "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."
NUREG-0800 Section 3.7.1.II.3, states "To be acceptable, the description of supporting media for each seismic Category I structure should include foundation embedment depth, depth of soil over bedrock, soil layering characteristics, For the foundation embedment depth, dimensions, and total structural heights, the PSAR refers to Figures 3.8-1 and 3.8-9.
However, the foundation embedment depth dimensions, which are required by SRP 3.7.1, is not able to be identified from these two figures.
Readiness Assessment - Phase 3 2
design groundwater elevation, dimensions of the structural foundation, total structural height, and soil properties such as shear wave velocity, shear modulus, material damping, including strain-dependent effect, as well as Poisson's ratios, and density as a function of depth."
3.7.2.1 - Seismic Analysis Method Technical judgment While the PSAR states: "five sets of three input motion ATHs are used as input for the SSI analyses to mitigate the uncertainty in the computed responses due to phasing of the time history frequency components.", there is no discussion of how the computed responses from these five sets of ATHs are combined to obtain the final design responses (eg. member forces, stresses, ISRS etc.).
3.7.2.2 - Natural Frequencies and Response Loads NUREG-0800 Section 3.7.2.II.2, Natural Frequencies and Responses Comment 1): This PSAR subsection states "refer to Appendix C for significant natural frequencies and SSE responses of Category I structure at the CRN site". Appendix 3C is referenced in the PSAR, however, App 3C is not provided in the eRR.
Comment 2): In addition, it is not clear to the NRC staff whether sufficient modes are included to achieve high percentage (eg. 90%)
mass participation. There is no statement or discussion associated with this technical requirement. An elaboration of this statement would provide more clarity for NRC staff.
3.7.2.9 - Effects of Parameter Variations on Responses NUREG-0800 Section 3.7.2.II.9, Effects of Parameter Variations on Floor Response Spectra Comment 1): While sensitivity analyses are performed to assess the effect of the variations of various analysis parameters and conditions, there is no discussion of the sensitivity results or conclusions on the selections of the sets of the analyses that are used in the final design evaluation.
Comment 2): Appendix C is referred for the results of the sensitivity analyses. Appendix C is also referred for the results of modal analysis and structural responses in PSAR Subsection 3.7.2.2. The Appendix (C or otherwise) that
Readiness Assessment - Phase 3 3
documents the results of sensitivity analyses was not made available for review.
3.7.3.1.3 - Static Coefficient NUREG-0800 Section 3.7.2.II.1.B, states "To obtain an equivalent static load for an SSC that can be represented by a simple model, a factor of 1.5 is applied to the peak spectral acceleration of the applicable ground or floor response spectrum."
In this PSAR subsection, it states "Response loads are determined statically by multiplying the equipment mass by a static coefficient equal to 1.5 times the maximum spectral acceleration that corresponds to the first mode of the equipment in accordance with NUREG-0800, SRP 3.7.2, Subsection II.1.B.". This statement is not correct as the NUREG-0800 specifies the use of peak spectral acceleration as opposed to the spectral acceleration that corresponds to the first mode of the equipment.
Justification of using the spectral acceleration corresponding to the first mode of equipment should be provided.
3.7.3.9 - Multiple-Supported Equipment and Components with Distinct Inputs NUREG-0800 Section 3.7.3.II.9, Multiply Supported Equipment and Components with Distinct Inputs Comment 1): There are two methods that are used when using time history analysis.
However, from the description of each method, the difference between these two methods is unclear.
Comment 2): The description of the response spectrum method does not appear to be related to the consideration of distinct inputs when applying response spectrum method. The requirements/acceptance criteria specified in NUREG-0800 3.7.3.II.9 should be included.
3.7.4 - Seismic Instrumentation 10 CFR Part 50, Appendix S, Paragraph IV.a.4, requires that suitable instrumentation be provided to promptly evaluate the seismic response of nuclear power plant features important to safety after an earthquake. Appendix S (Paragraph IV.a.3) also requires shutdown of the nuclear power plant if vibratory ground motion exceeds that of the Section 3.7.4 of the PSAR refers to the BWRX-300 seismic instrumentation system. If there is a reference(s) to this specific instrumentation system (e.g., specific BWRX-300 design documents), the reference(s) should be provided since PSAR Section 3.7.4.2 "Location and Description of Instrumentation" does not provide a description of the proposed seismic instrumentation.
Readiness Assessment - Phase 3 4
Operating Basis Earthquake (OBE) occurs.
3.7.4 - Seismic Instrumentation 10 CFR Part 50, Appendix S (Paragraphs IV.a.3 and IV.a.4)
PSAR Section 3.7.4.2 states that the location of the instrumentation follows the guidance of RG 1.12, however, no details regarding the specific locations of the instrumentation are provided.
As such, the specific locations of all proposed instrumentation should be provided in the PSAR.
3.7.4 - Seismic Instrumentation 10 CFR Part 50, Appendix S ( Paragraphs IV.a.3 and IV.a.4)
The title of PSAR Section 3.7.4.2.2 "Structure and Equipment Instrumentation" suggests that some instruments are located at elevations in structures as well as on equipment. No instrumentation location specifics are provided.
Section B (Background) of RG 1.12, notes that "instrumentation is not located on equipment, piping, or supports since experience has shown that data obtained at these locations are obscured by the vibratory motion associated with normal plant operation." For this reason, the locations of the in-structure instrumentation should be clarified.
3.7.4 - Seismic Instrumentation 10 CFR Part 50, Appendix S ( Paragraphs IV.a.3 and IV.a.4)
PSAR Section 3.7.4.2.2 states that "for sensors installed in inaccessible areas, provisions for data recording and an external remote alarm indicating actuation". The PSAR should indicate which sensors will be located in inaccessible areas and whether their design will allow for remote in-service testing.
3.7.4 - Seismic Instrumentation 10 CFR Part 50, Appendix S ( Paragraphs IV.a.3 and IV.a.4)
Section 3.7.4 refers directly to ANS 2.23, rather than RG 1.166. Although RG 1.166 endorses ANS 2.23, clarifications are provided in Section C of this RG. As such, the PSAR should address these clarifications.
Readiness Assessment - Phase 3 5
3.7.4 - Seismic Instrumentation 10 CFR Part 50, Appendix S ( Paragraphs IV.a.3 and IV.a.4)
PSAR Section 3.7.4 refers to RG 1.12, RG 1.166, and ANSI/ANS-2.23, and states that the instrumentation and post-earthquake actions of these RGs and standards are followed.
However, in many places, more specificity with respect to how these RGs and standards will be followed, is needed.
3.7.4 - Seismic Instrumentation 10 CFR Part 50, Appendix S ( Paragraphs IV.a.3 and IV.a.4)
With respect to pre-earthquake planning, shutdown, and post-earthquake actions, Section 3.7.4.4 of the PSAR references Sections 6.3.1, 6.3.2, 7.1, 7.2, 8.1, and 8.2 of ANSI/ANS-2.23, as well as Appendix A of RG 1.166. The PSAR should clarify if other sections of this standard will be followed.
3.7.4 - Seismic Instrumentation 10 CFR Part 50, Appendix S ( Paragraphs IV.a.3 and IV.a.4)
Section 3.7.4.4 of the PSAR states that the "plant is shut down if the walkdown inspections discover damage to equipment that would affect the safe operation of the plant, or if the Operating Basis Earthquake (OBE) or Safe Shutdown Earthquake (SSE) exceedance criteria listed in Sections 6.3.1 and 6.3.2 of ANSI/ANS-2.23, respectively, are met."
However, this statement is not consistent with Section 6.2 of ANSI/ANS-2.23, which states that if "the OBE exceedance criterion is exceeded and/or any significant damage to safety related (SR) and non-SR systems, structures, or components (SSCs) important to safe plant operation is observed, an orderly plant shutdown is required for U.S. plants." As such, the PSAR should clarify the shutdown criteria.
Chapter/Section 3.8 - Design of Category I Structures Section Basis for Observation/Comment Readiness Assessment Observations/Comments 3.8 - Design of Category I Structures 10 CFR Part 50 Appendix B
There are references to many Appendices, but those are not available on the portal for review (Appendices 3B, 3F, 3G, 3H, 3I), therefore readiness assessment of those related parts was not conducted. If ch 3 appendices are provided in the eRR, NRC staff can provide further observations.
3.8.1.5 - Structural Acceptance Criteria ASME Section III, Table CC-3230-1 According to ASME Section III, Table CC-3230-1, Load case Ha - internal flooding is included in
Readiness Assessment - Phase 3 6
load combinations for the abnormal/severe environmental category. However, the Ha load case is not included in Table-3.8-1 for SCCV.
Confirm whether internal flooding load applies to the SCCV containment walls design.
3.8.2.4 - Design and Analysis Procedures NUREG-0800 Section 3.8.2.II.4.C, Computer Programs The PSAR does not identify the computer program(s) that is/are used to perform the FE analyses of Class MC steel components.
3.8.3.7 - Testing and Inservice Surveillance Requirements NUREG-0800 Section 3.8.3.I.7, Testing and Inservice Surveillance Programs.
Although it is stated that testing and surveillance of containment internal structures is not required, accommodations should be provided for access to critical areas and penetrations that require inspections.
3.8.5.1.1 - RB and Containment Common Mat Foundation Technical Judgment Based on Figure 3.8-2, the reactor building foundation and the containment foundation appears to be two structural elements with different materials. Since the containment foundation (SCC member) is integral with the RB (reinforced concrete) mat foundation, appropriate reinforcement details need to be considered to provide a monolithic connection.
The joint should also be evaluated for forces from all possible loading combinations and conditions.
3.8 - Design of Category I Structures 10 CFR Part 50 Appendix A GDC 2
- 1. Subsection 3.8.4.4.1 states that the Control Building that houses the main control room and electrical control and instrumentation equipment is a Category 2 structure.
RG 1.29 - Seismic Design Classification for Nuclear Power Plans, Part C, Subsection 1.d, bullet 5 lists "the control room, including its associated equipment and all equipment needed to maintain the control room within safe habitability limits for personnel and safe environmental limits for vital equipment." as examples of category 1 structure.
Request clarification on whether the Control Building discussed in section 3.8.4.4.1 is
Readiness Assessment - Phase 3 7
appropriately categorized as seismic category 2 or 1.
Chapter/Section 9.1 Section Basis for Observation/Comment Readiness Assessment Observations/Comments 9.1 - Fuel Storage and Handling 10 CFR Part 50, Appendix A GDC 4 and GDC 61 Section 9.1 refers to neutron absorbing materials and associated testing without naming specific materials or test methods. The use of a material that has previously been reviewed and approved by the staff will result in a less complicated review process that does not require the staff to review initial material qualification testing.
In addition, guidance on an acceptable neutron absorbing material surveillance program is available in NEI 16-03, Guidance for Monitoring of Fixed Neutron Absorbers in Spent Fuel Pools.
9.1 - Fuel Storage and Handling 10 CFR 50.68, GDC 62
- 1. Missing design specifications of the spent fuel rack and spent fuel pool design.
- 2. Missing criticality safety analysis.
- 3. Missing information on the computer codes used for criticality safety analysis.
- 4. Missing information on what cross section library is used in criticality safety.
- 5. Missing code benchmarking analysis.
The draft section states that the criticality safety analysis [for spent fuel pool] will be provided in the FSAR, draft PSAR Chapter 9.1, Revision B, Page 41, fifth paragraph). This is contradictory to 10 CFR 50.68 which requires this information to be provided in order to obtain a CP 9.2 N/a No observations