ML24033A206

From kanterella
Jump to navigation Jump to search
GEH BWRX-300 SMR TR RAI - FW (Proprietary) GE Hitachi Request for Additional Information (RAI-10121-R1) Letter No. 18 for Topical Report NEDC-33926P
ML24033A206
Person / Time
Site: 99900003
Issue date: 02/02/2024
From:
NRC
To:
NRC/NRR/DNRL/NRLB
References
Download: ML24033A206 (20)
v • d • e


Text

From:

Jim Shea Sent:

Friday, February 2, 2024 9:47 AM To:

GEH-BWRX-300RAIsPEm Resource Cc:

Jordan Glisan

Subject:

FW: (PROPRIETARY) GE Hitachi Request for Additional Information (RAI-10121-R1) Letter No. 18 for Topical Report NEDC-33926P Attachments:

Public Letter No. 18 RAI-10121-R1-FINAL-REDACTED LTR NEDC-33926P Containment and Reactor Building Structural Design.pdf From: Jordan Glisan <Jordan.Glisan@nrc.gov>

Sent: Friday, January 26, 2024 5:25 PM To: KARKOUR, SUZANNE (GE Power Portfolio) <SUZANNE.KARKOUR@ge.com>

Cc: Wadkins, George (GE Power Portfolio) <George.Wadkins@ge.com>; Michelle Hayes

<Michelle.Hayes@nrc.gov>; Ian Tseng <Ian.Tseng@nrc.gov>; Jim Shea <James.Shea@nrc.gov>; George Thomas <George.Thomas2@nrc.gov>; Stoyanov, George <George.Stoyanov@cnsc-ccsn.gc.ca>

Subject:

(PROPRIETARY) GE Hitachi Request for Additional Information (RAI-10121-R1) for Topical Report NEDC-33926P Good afternoon Suzanne, Attached, please find the NRC staffs request for additional information (RAI) public redacted version concerning the review of NEDC-33926P/NEDO-33926, Revision 1, BWRX-300 Steel-Plate Composite Containment Vessel (SCCV) and Reactor Building (RB) Structural Design (Agencywide Documents Access and Management System Accession No. ML23230B215).

Please submit your technically correct and complete response by February 12, 2024, for those RAIs that can be responded to in 30 days and by March 13, 2024, for those RAIs where a 60-day response time was requested. Please submit to the NRC Document Control Desk.

During an email response to the staff on January 26, 2024 and during the previous clarification call on that day you confirmed that the RAI content that contained GEH proprietary information was correctly identified.

If you have any questions, please let me know.

Docket No.: 99900003 Jordan Glisan Project Manager U.S. Nuclear Regulatory Commission NRR/DNRL/NLIB Phone: 301-415-3478

Hearing Identifier:

GEH_BWRX300_RAIs_Public Email Number:

20 Mail Envelope Properties (BLAPR09MB689914EB0BF599DC2280DB5B94422)

Subject:

FW (PROPRIETARY) GE Hitachi Request for Additional Information (RAI-10121-R1) Letter No. 18 for Topical Report NEDC-33926P Sent Date:

2/2/2024 9:47:28 AM Received Date:

2/2/2024 9:47:32 AM From:

Jim Shea Created By:

James.Shea@nrc.gov Recipients:

"Jordan Glisan" <Jordan.Glisan@nrc.gov>

Tracking Status: None "GEH-BWRX-300RAIsPEm Resource" <GEH-BWRX-300RAIsPEm.Resource@usnrc.onmicrosoft.com>

Tracking Status: None Post Office:

BLAPR09MB6899.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 1893 2/2/2024 9:47:32 AM image001.jpg 3331 image002.png 8597 Public Letter No. 18 RAI-10121-R1-FINAL-REDACTED LTR NEDC-33926P Containment and Reactor Building Structural Design.pdf 270233 Options Priority:

Normal Return Notification:

No Reply Requested:

No Sensitivity:

Normal Expiration Date:

REQUEST FOR ADDITIONAL INFORMATION No. 018 (RAI-10121-R1)

BY THE OFFICE OF NUCLEAR REACTOR REGULATION GEH - BWRX-300 REVIEW OF TOPICAL REPORT NEDC-33926P "CONTAINMENT AND REACTOR BUILDING STRUCTURAL DESIGN "

GE HITACHI NUCLEAR ENERGY DOCKET NO. 99900003 ISSUE DATE: 01/26/2024

=

Background===

By letter dated August 18, 2023, GE-Hitachi Nuclear Energy Americas, LLC (GEH) submitted topical report, NEDC-33926P/NEDO-33926, Revision 1, BWRX-300 Steel-Plate Composite Containment Vessel (SCCV) and Reactor Building (RB) Structural Design (Agencywide Documents Access and Management System Accession No. ML23230B215). The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided in the topical report and determined that additional information is needed to complete its review.

Regulatory Basis For Question 1 Only:

The Commissions Severe Accident Performance Goal for containment structures stipulated in SECY-93-087, Policy, Technical, and Licensing Issues Pertaining to Evolutionary and Advanced Light-Water Reactor (ALWR) Designs, dated April 2, 1993 (ML003708021), and approved in Items 6 and 17 of staff requirements memorandum (SRM) dated July 21, 1993 (ML003708056),

requires applicants to address the NRCs performance goal for containment structures for maintaining its role as a reliable, leak-tight barrier against uncontrolled release of fission products under the more likely severe accident challenges and a margins type assessment of external events (beyond design basis seismic event.

For Questions 2 thru 11:

10 CFR Part 50, Appendix A - General Design Criteria for Nuclear Power Plants, Criterion 1 Quality standards and records, requires in part: Structures, systems, and components important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed. Where generally recognized codes and standards are used, they shall be identified and evaluated to determine their applicability, adequacy, and sufficiency and shall be supplemented or modified as necessary to assure a quality product in keeping with the required safety function.

Question 1 RAI 2.1.2-1

Background

The GEH licensing topical report NEDC-33926P (or LTR), in Section 2.1.2, 10 CFR 100.21, includes this site-specific regulation 10 CFR 100.21 Non-seismic siting criteria as applicable to the scope of the structural design/construction LTR. It states in the Statement of Compliance:

As discussed in Subsection 6.23.3, the calculated release for the more likely severe accident challenges, following the initial 24-hour period, meets the site-specific radiological dose consequences in accordance with the requirements of 10 CFR 100.21 and 10 CFR 50.34[(a)(1)]. Regulatory Guide (RG) 1.216, referenced in LTR Section 6.23.3, includes guidance for meeting containment performance goal under severe accidents, but does not provide guidance of an acceptable way to perform radiological release calculations to meet site-specific siting criteria in 10 CFR 100.21.

SRP 19.0, Probabilistic Risk Assessment (PRA) and Severe Accident Evaluation for New Reactors,Section I Areas of Review states, in part:

"The structural performance of the containment under severe accident loads reviewed by the staff encompasses: (1) the applicants assessment of the Level C (or factored load) pressure capability of the containment in accordance with 10 CFR 50.44(c)(5); (2) the applicants demonstration of the containment capability to withstand the pressure and temperature loads induced by the more likely severe accident scenarios as stipulated in SECY-93-087, Policy, Technical, and Licensing Issues Pertaining to Evolutionary and Advanced Light-Water Reactor Designs,Section I.J; (3) the applicants containment structural fragility assessment for over-pressurization; and (4) the applicants assessment of the seismic capacity of the containment structure in meeting the expectation documented in SECY-93-087,Section II.N."

Issue

1. The requirements of 10 CFR 100.21 pertain to site-specific siting criteria and requirements, which among others, includes evaluation of site atmospheric dispersion characteristics and parameters such that radiological dose consequences of postulated accidents [design basis] shall meet the criteria set forth in 50.34(a)(1) for the type of facility proposed to be located at the site. The requirements apply to calculation of offsite radiological release and consequences that appear to be outside the scope of the LTR for structural design and construction of the Integrated Reactor Building using steel-plate composite modules with diaphragm plates (DP-SC).
2. Further, from the reference made in the LTR 2.1.2 statement of compliance to LTR Section 6.23.3 SCCV Behavior Following a Severe Accident, it appears that LTR Section 2.1.2 is intended to address compliance with the Commissions containment performance goal policy for advanced light water reactors (LWRs) under severe accidents [beyond design basis] stipulated in SECY-93-087 dated April 2, 1993 (ML003708021), and its related Staff Requirements Memorandum (SRM) dated July 21, 1993 (ML003708056). Guidance for severe accident performance goal evaluation is provided in regulatory position C.3 of RG 1.216, Revision 0, which is used in LTR Section 6.23.3, and in NUREG-0800 SRP Section 19.0. However, there is no discussion in LTR Section 2.2 regarding conformance to related NUREG-0800 SRP Section 19.0 regarding containment structural performance under severe accident loads, including seismic margins analysis, for new reactors for the areas of review encompassed in SRP 19.0 (i.e., the 4 areas stated in the Background Section above).

Request

1. Describe how the site-specific 10 CFR 100.21 regulation is in the scope of the BWRX-300 LTR for the DP-SC containment vessel (SCCV) and RB structural design methodology and

how it meets the requirements as claimed in the LTR 2.1.2 statement of compliance when calculation of radiological release, which is site-specific, is not performed, and appears to be outside the LTR scope. If determined to be outside the scope of the LTR, remove the related discussion in LTR Section 2.1.2.

2. Clarify if the discussion in LTR Section 2.1.2 is intended to cover the methodology that will be used to comply with the Commissions severe accident performance goal for containment identified in SECY-93-087 and related SRM, as indicated in LTR Section 6.23.3. If so, state the regulatory compliance requirement being addressed in LTR Section 2.1.2 and revise the LTR section consistent with that rather than 10 CFR 100.21.
3. Revise the LTR to include and address conformance with NUREG-0800 SRP 19.0 regarding the Commissions structural performance goal for containment structural integrity under severe accidents stipulated in SECY-93-087 (and it SRM) as encompassed in the four areas identified in Section I of SRP 19.0 (i.e., the 4 areas stated in the Background Section above), as applicable to the scope of the LTR.

Question 2 RAI 5.3-1

Background

As a result of the regulatory audit, GEH proposed a revision to the LTR that states in Section 5.3 in part:

"The faceplates of DP-SC modules are anchored using a combination of diaphragm plates and steel headed stud anchors with the webs of the modules (i.e., diaphragms plates), acting as ties preventing splitting of sections and serving as out-of-plane shear reinforcement. Steel headed stud anchors will not be used in inaccessible tight locations where the diaphragms plates ensure the section composite action, and the faceplate local buckling is proven not to exceed ANSI/AISC N690 Section N9.1.3 limits for faceplate slenderness requirements.

The BWRX-300 construction uses yielding steel headed stud anchors in all composite construction. Steel headed stud anchors are designed and detailed per ANSI/AISC 360-16 (Reference 9-57), Section I8.3 requirements.

As the diaphragm plates are quite substantial, and do not need additional contributions from the stud anchors to develop the yield strength of the steel faceplates or to provide interfacial shear strength for the panels, headed studs of DP-SC panels are designed to meet the requirements of ANSI/AISC N690, Section N9.1.3 for faceplate slenderness requirements only, in order to improve the stability of the steel faceplates after concrete casting. The headed stud diameter, height, maximum and minimum spacing are computed as discussed in Reference 9-58 to meet both stiffness and force requirements of the headed studs.

Requirements of ANSI/AISC N690, Section N9.1.4b for interfacial shear failure prevention are not applicable to DP-SC modules as confirmed by NRIC specimens (Out-Of-Plane-Shear (OOPV)-1 and OOPV-2) testing (see Section 7.0)."

During the regulatory audit, GEH stated that the diaphragm plate will contribute to the development of the faceplate yield strength due to the confinement and friction effect between the concrete and the faceplates.

Issue

1. LTR Section 5.3 states that steel headed stud anchors are designed and detailed per ANSI/AISC 360-16, Section I8.3 requirements while ANSI/AISC N690-18 refers to Sections I8.1 and I8.3 of ANSI/AISC 360-16 for the requirements for steel headed stud anchors.

Further, Chapter I of ANSI/AISC 360-16 is modified by Chapter NI of ANSI/AISC N690-18, the impact of which is not addressed in the LTR.

2. LTR Section 5.3, as modified, states that steel headed stud anchors will not be used in inaccessible tight locations where the diaphragm plates ensure the section composite action and the faceplate local buckling is proven not to exceed ANSI/AISC N690 Section N9.1.3 limits for faceplate slenderness requirements. This statement refers to inaccessible tight locations." It is not clear why inaccessibility is a motivation for not using steel headed study anchors if the modules are shop fabricated. Also, it does not appear to address if those tight locations are localized areas.
3. LTR Section 5.3 states that the diaphragm plates are quite substantial, and do not need additional contributions from the stud anchors to develop the yield strength of the steel faceplates or to provide interfacial shear strength for the panels. In ANSI/AISC N690-18, shear connectors, for example steel headed stud anchors and ties, are discrete and not continuous elements along a direction of a wall or floor. While diaphragm plates may be considered discrete in one direction, they are continuous in the direction of the axis of the diaphragm plates. The mechanisms for development of the yield strength of the steel faceplates or interfacial shear strength for continuous ties like the diaphragm plates do not appear to be demonstrated in the LTR. During the regulatory audit, GEH stated that the presence of diaphragm plates will develop the faceplate yield strength due to the confinement and friction effect between the concrete and the faceplates but does not provide a demonstration as to how such friction and confinement effects will be developed including, among others, considerations of concrete shrinkage. Therefore, given that the NRIC tests used headed steel studs, the LTR does not appear to demonstrate how the required composite action of the faceplates is achieved with the concrete infill for the DP-SC module without headed steel stud anchors.
4. Based on information in the referenced LTR Section 7.0, it is unclear how the requirements of ANSI/AISC N690, Section N9.1.4b for interfacial shear failure prevention are not applicable to DP-SC modules was demonstrated by NRIC specimens OOPV-1 and OOPV-2 testing, as stated in the LTR, Request
1. Clarify if steel headed stud anchors, in addition to the requirements in Section N9.1.4a of ANSI/AISC N690, will be detailed and designed per the requirements of both Section I8.1 and I8.3 of ANSI/AISC 360-16 or only Section I8.3 of ANSI/AISC 360-16 and address any impact of the modifications to Chapter I of ANSI/AISC 360-16 of stipulated in Chapter NI of ANSI/AISC N690-18. Justify related exceptions taken, if any, to ANSI/AISC N690-18 requirements.
2. Clarify why inaccessibility of tight areas is an impediment to the use of steel headed stud anchors. Clarify also if the tight areas where steel headed stud anchors would not be used are localized areas.
3. If headed steel studs are not mandatory for SCCV and RB DP-SC modules, justify how the required composite action with concrete infill is achieved for the DP-SC module without headed stud anchors, and given that headed anchors were used in the NRIC prototype testing, provide: (a) supporting test data that establishes adequate composite action and performance of the DP-SC modules without headed stud anchors, for applicable limit states; and (b) results of benchmarked finite element model analysis together with mechanics-based systems to calculate the contribution of the diaphragm plates to develop the faceplate yield strength as well as interfacial shear strength. Consider development of faceplate yielding and interfacial shear in the direction of the diaphragm plates as well as in the direction perpendicular to the diaphragm plates and account for potential concrete infill shrinkage.
4. Describe, with supporting bases, the criteria used to determine if steel headed stud anchors are not mandatory and justify the apparent deviation from Section N9.1.4 in ANSI/AISC N690.
5. Explain how the requirements of ANSI/AISC N690, Section N9.1.4b for interfacial shear failure prevention are not applicable to DP-SC modules was demonstrated by NRIC specimens OOPV-1 and OOPV-2 testing, as stated in the LTR.
6. Update the LTR, as appropriate, consistent with the responses to the above.

Question 3 RAI 5.4-1

Background

LTR Section 5.4 Diaphragm Requirements, states: The spacing of the module's diaphragm plates is limited to 1.0 times the panel thickness,

, similar to maximum tie spacing in ANSI/AISC N690 and ACI 349 for reinforced concrete. Tie plates or bars may be added for additional stiffness and strength.

Issue LTR Section 5.4 is unclear on what is meant by the statement: Tie plates or bars may be added for additional stiffness and strength, and what are the additional criteria or requirements to determine that, and/or if there needs to be additional criteria to determine spacing of diaphragm plates in DP-SC modules.

Request Clarify what is meant by the statement: Tie plates or bars may be added for additional stiffness and strength. State with the basis the additional criteria or requirements to determine that, and/or additional criteria to determine required spacing of diaphragm plates in DP-SC modules.

Question 4 RAI 5.5.1-1

Background

As a result of the regulatory audit, GEH proposed a revision to the LTR that states in Section 5.5.1 in part:

"Alternatively, as permitted in ANSI/AISC 360-22, Appendix 4, an explicit model, representing the different components of steel plates, discretized studs, concrete infill, and contact between different components, simulating both thermal and mechanical responses of temperature-dependent properties of the steel plates and concrete infill can be used to estimate the temperature time histories and through-section temperature profiles produced by the thermal accident conditions for the different thermal gradient scenarios to calculate maximum corresponding structural demands (e.g. axial and/or flexure), both globally and locally."

LTR Section 6.5.1 Structural Thermal Analysis, states, in the second sentence that:

((&......;.................................................

................. &......;&......;..))

Issue

1. The LTR is unclear as to which provision of ANSI/AISC 360-22 Appendix 4 is being referred to in the Section 5.5.1 paragraph cited above, and if and how it would be affected by the modifications in Appendix N4 of the nuclear standard AISC N690-18.
2. The LTR considers an explicit model that can account for heat transfer as an alternative to the model allowed by N690, Section N9.2.4. The LTR does not have justification on the effects of thermal expansion over the full length of the structure and through the section with consideration of the time lag between steel and concrete in developing the design temperature(s) which can be achieved only by testing, analysis with explicit modeling of the steel and concrete materials with their geometry or a combination thereof. As such, explicit analysis should not be an alternative option, but integral part of the heat transfer analysis discussed in Section 5.5.1.
3. LTR Section 6.5.1 is unclear on how the ((.........................

.............................., &.....;.....,)) is calculated.

Request

1. State which specific provision of ANSI/AISC 360-22 Appendix 4 is being referred to in Section 5.5.1 paragraph cited above, and whether it would be affected by the modifications in Appendix N4 of the nuclear standard AISC N690-18. If affected, address the impact of the modification, or justify any deviation being taken.
2. State how the effects of time lag in developing design temperatures between steel and concrete will be considered in design.
3. Describe how the ((.............................................

.........., &.....;.....)) in LTR Section 5.1 is calculated.

4. Update the LTR, as appropriate, consistent with the responses to the above.

Question 5 RAI 5.7.2-1

Background

As a result of the regulatory audit, GEH proposed a revision to the LTR that states in Section 5.7.2 that for surface temperatures up to 482 degrees Fahrenheit (250 degrees Celsius), per Reference 9-60, Pno is computed using Eq. 5-16 in the LTR. Section 5.7.2 of the LTR, as modified, further states that Equation 5-16 is consistent with ANSI/AISC N690, Section N9.3.2.

The proposed revision to the LTR states in Section 5.2.1: The concrete temperature limitations for normal operational and accidental conditions meet those specified in ACI 349, Appendix E, Section E.4. Reduction in concrete properties at elevated temperature is per ANSI/AISC N690, Appendix N4.

The proposed revision to the LTR states in Section 5.2.2: The effect of elevated temperatures on the mechanical properties of steel materials of DP-SC modules is determined in accordance with ANSI/AISC N690, Section NB3.3.

Issue The form of Equation 5-16 in Section 5.7.2 of the LTR is consistent with Equation A-N9-16 for SC sections with non-slender faceplates in Section N9.3.2 of ANSI/AISC N690-18. However, Section N9.3.2 of ANSI/AISC N690-18 does not state a range of temperatures for the use of Equation A-N9-16. Instead, Section N9.3.2 in the Commentary of ANSI/AISC N690-18 provides results of analyses reported in Reference 9-60 which show the results of finite element analyses using temperature dependent material properties up to 482 degrees Fahrenheit (250 degrees Celsius) normalized to the values calculated using Equation A-N9-16 and ambient material properties. The results show that Equation A-N9-16 is slightly unconservative for temperatures above 482 degrees Fahrenheit even though the Commentary for Section N9.3.2 recommends the use of Equation A-N9-16 for SC wall panel sections subjected to accident thermal loading causing surface temperatures up to 300 degrees Fahrenheit. Neither Section N9.3.2 of ANSI/AISC N690-18 nor Commentary to Section N9.3.2 as well as Reference 9-60 address cases when temperatures in the concrete infill exceed the temperature limits in Section E.4 of Appendix E of ACI 349-13, referenced in LTR Section 5.2.1. Similarly, neither Section N9.3.2 of ANSI/AISC N690 nor the Commentary to Section N9.3.2 or Reference 9-60 address surface temperature limits for the steel faceplates for normal operating conditions and accident conditions.

Request Revise the LTR to clarify and state if the use of LTR Equation 5-16 will conform to temperature limits and/or temperature-dependent properties (when limits are exceeded) consistent with (i)

LTR Section 5.2.1, as modified (references Section E.4 of Appendix E of ACI 349-13 and ANSI/AISC N690, Appendix N4), for the concrete infill of the DP-SC modules, and (ii) LTR Section 5.2.2, as modified (references Section NB3.3 of ANSI/AISC N690-18), for the steel faceplates and diaphragm plates of the DP-SC modules. If not, state the deviation being taken and provide the technical basis for deviation.

Question 6 RAI 5.8-1

Background

LTR Section 5.8, Design for Impactive and Impulsive Loads, provides the approach for the design to resist effects of impulsive loadings from pipe rupture as well as the impact of missiles resulting from pipe rupture, tornadoes, aircraft impact or any other missile.

As a result of the regulatory audit, GEH proposed a revision to the LTR that states in revised Section 5.8.1.3 that allowable ductility ratios, support rotations and steel strains for the design of DP-SC structures subjected to impulsive loads in addition to other simultaneously acting loads. Table 5-2 presents the allowable ductility ratios and the allowable support rotations for various structural components, response modes and levels of damage. Table 5-3 provides allowable strains for steel for various steel materials and levels of damage.

LTR Section 5.8.3, Impact or Impulse Design for Global Response, provides approaches to determine the global response of DP-SC structures subject to impactive and impulsive loads.

The statement of conformance in the proposed revision to LTR Section 2.3.12, Regulatory Guide 1.243, states: The analysis, design, construction, testing, and evaluation of the non-containment Seismic Category I SC structures follow the guidance of RG 1.243 and the provisions of ANSI/AISC N690, Appendix N9 supplemented by the additional criteria and requirements provided in Section 5.0 of this report.

Issue

1. Footnotes 11, 12 and 13 in the proposed revision to Table 5.2 relate the allowable level of damage to load definitions in CNSC REGDOC-2.5.2 and IAEA SR No. 87. However, these footnotes do not relate the allowable levels of damage in Table 5-2 and their associated allowable ductility and support rotations to load combination categories in the ASME Section III, Division 2 code for concrete containments and in the ANSI/AISC N690 code for non-containment structures. Specifically, the footnotes do not identify which levels of damage and deformation limits apply to (1) the normal and severe environmental load combination categories and (2) the abnormal and extreme environmental load combination categories. Table 5-3 also does not identify which levels of damage apply to (1) the normal and severe environmental load categories and (2) the abnormal and extreme environmental load categories. Further, Table 5-3 includes a row for Grade 60 reinforcing steel, which appears to be not applicable to DP-SC modules in the LTR scope.
2. Table 5-2 provides allowable ductility ratios for shear in slabs (and beams) that are greater than the allowable ductility ratios for shear in slabs (and beams) in Regulatory Position 11.1.7 of Regulatory Guide (RG) 1.243, which states: "For shear-controlled SC walls with yielding shear reinforcement spaced at section thickness divided by two or smaller, the ductility ratio is no greater than 1.3. For shear-controlled SC walls with yielding shear reinforcement spaced in excess of the section thickness divided by two or for shear-controlled SC walls with nonyielding reinforcement, the ductility ratio is limited to 1.0. Higher ductility factors up to the values in ANSI/AISC N690-18, Section N9.6b should be justified on a case-specific basis." Table 5-2 does not appear to provide allowable ductility limits for out-of-plane shear for walls subjected to impactive and impulsive loads. It only includes allowable ductility ratios for in-plane shear. Table 5-2 includes a flexure mechanism for shear walls and allowable ductility ratio for that flexure mechanism. However, Table 5-2 does not clarify if that response mechanism is out-of-plane flexure or in-plane flexure.
3. Table 5-2 provides allowable ductility ratios for compression of beams, slabs and walls in compression that are greater than the allowable ductility ratios in Regulatory Position 11.1.5 of RG 1.243. Footnote 10 refers to ACI 349 Section F3.8 for allowable ductility ratios for beam-columns, walls and slabs in combined flexure and compression, which differ from those in Regulatory Position 11.1.5 of RG 1.243.
4. Section 5.8.3 describes the impact and impulsive design for global component response.

The description in the LTR Section 5.8.3 does not address Regulatory Position 11.1.8.3 in RG 1.243 which states: "In the case of the reaction shear (beam action condition) at the supports, the effective width of the critical section for the shear beam capacity at the supports is to be determined according to the zone of influence induced by the local loads instead of the entire width of the support. The zone of influence induced by the concentrated loads may be determined, for example, by an analysis.

Request

1. (i) Identify which levels of damage and deformation limits in Table 5-2 apply to (1) the normal and severe environmental load combination categories and (2) the abnormal and extreme environmental load combination categories, for both containment and non-containment structures or components; (ii) Identify which levels of damage in Table 5-3 apply to (1) the normal and severe environmental load categories and (2) the abnormal and extreme environmental load categories, for both containment and non-containment structures or components; and (iii) Delete the row for Grade 60 reinforcing steel in Table 5-3 if determined to be not applicable to the scope of the LTR for DP-SC modules.
2. (i) If the allowable ductility ratios for shear in beams, slabs (out-of-plane) and walls (out-of-plane) for SC modules in Regulatory Position 11.1.7 of RG 1.243 are not used, provide justification for the use of the allowable ductility ratios for shear in Table 5-2 for the DP-SC modules. (ii) Clarify if the allowable ductility ratios for wall in flexure are for out-of-plane flexure or in-plane flexure.
3. If the allowable ductility ratios for compression in Regulatory Position 11.1.5 of RG 1.243 for SC modules are not used, provide justification for the use of the allowable ductility ratios for compression of DP-SC modules in Table 5-2 including the use of the approach referred to in footnote 10.
4. Clarify how approaches in Section 5.8.3 for the global component response for the design of DP-SC modules to resist impactive and impulsive loads will address or account for Regulatory Position 11.1.8.3 in RG 1.243.
5. Update the LTR, as appropriate, consistent with the responses to the above.

Question 7 RAI 5.18-1

Background

LTR Section 5.18 Aging Management, Inservice Inspection, and Testing Requirements for the Integrated RB, and referenced in LTR Section 6.22, states in part:

"As part of the NRIC project, the Electric Power Research Institute (EPRI) demonstrated the effectiveness of some potential nondestructive examination techniques on mockups/prototypes fabricated with DP-SC modules to inspect concrete placed between the faceplates. The techniques used for this demonstration included high-energy X-ray and low-frequency ultrasound testing."

As demonstrated by testing carried out as part of the NRIC project, techniques for in-service inspection and testing that may be deployed for the BWRX-300 DP-SC modules include:

Guided wave phased-array (screening of defects within steel plates)

High-energy X-ray (location of voids and foreign material within concrete)

Low-frequency ultrasound (evaluation of steel plate contact and defects within the concrete)

Additional methods may be implemented after further evaluation during detailed design.

DP-SC containment internal structures (e.g., RPV pedestal) exposed to high levels of neutron irradiation, prone to neutron irradiation embrittlement, are evaluated and monitored for the effects on faceplates mechanical properties (i.e., strength and fracture toughness). Radiation embrittlement is evaluated and monitored to ensure the DP-SC component integrity during the plant lifespan."

Issue

1. The above referenced NRIC Project Report, provided during audit in the electronic reading room (ERR) as GE Hitachi Report 007N5115, Revision 1, Demonstration of Nondestructive Evaluation of Concrete in Mockup and Prototypes, is an important technical basis document for proposed non-destructive inspection and testing methods that may be deployed for aging management of the DP-SC modules; and needs to be docketed.
2. The LTR does not appear to provide a plan to develop measured baseline data of material properties and other parameters by testing during original construction that are necessary to facilitate evaluation and monitoring and trending of applicable aging effects, including irradiation embrittlement, for the DP-SC modules, during the service life.

Request

1. Provide on the docket GE Hitachi Report 007N5115, Revision 1, Demonstration of Nondestructive Evaluation of Concrete in Mockup and Prototypes.
2. Update the LTR to describe the plan for identifying and developing measured baseline data of necessary material properties and other parameters by testing during original construction that are necessary to facilitate evaluation and monitoring and trending of applicable aging effects, including irradiation embrittlement, for the DP-SC modules, during the service life.

Question 8 RAI 6.2-1

Background

LTR Section 6.2, Materials, states, in part: The properties of concrete fill and structural steel are in accordance with guidelines of ASME BPVC,Section III, Division 2, Subsection CC [ASME Section III-2], Article CC-2000, endorsed by US NRC RG 1.136, as applicable."

LTR Section 6.2.4, Load Bearing Steel, states that, if used, load bearing steel materials meet requirements of CC-2700 of ASME Section III-2.

Issue

1. LTR Section 6.2 appears to not address or lacks clarity regarding requirements for authorized inspector and certification of material of SCCV DP-SC modules stipulated for concrete containments in Sub-articles CC-2122, Special Requirements, and CC-2130, Certification of Material, of ASME Section III-2.
2. CC-2700 of ASME Section III-2 is titled, Embedment Anchors, and LTR Section 6.2.4 is unclear as to what specific load bearing steel material the section applies for the SCCV.

Request

1. Provide requirements in the LTR for authorized inspector and certification of material applicable to SCCV DP-SC modules analogous to CC-2130 Certification of Material of ASME Section III-2; OR clarify if CC-2122 and CC-2130 applies in their entirety.
2. Update the LTR to clarify what specific load bearing steel materials does LTR Section 6.2.4 apply to, if used, for the SCCV consistent with definition of terms in CC-2111 and D2-II-1000 of ASME Section III-2.

Question 9 RAI 6.13-1

=

Background===

LTR Section 6.13, Welded Construction of Diaphragm Plate Steel-Plate Composite Containment, refers to ((..............-.,...-.........-......

..........)). Table 6-2 Weld Categories Applicability to Steel-Plate Composite Containment Vessel, in the third column, states applicability of each weld category to SCCV.

As a result of the regulatory audit, GEH proposed a revision to the LTR that states in revised Section 6.14: ASME BPVC, 2021 Edition,Section III, Division 2, Subsection CC (ASME III-2) does not include requirements for the design of SC connections. The requirements of ANSI/AISC 360-16 and Design Guide 32 are adapted, as applicable as described in Section 5.11, to the design of the SCCV splices, slab-to-wall and wall-to-mat foundation connections.

LTR Section 6.15 states ((.......................................-..

........................-...-................)).

Issue

1. While Figure CC-3831-1, Illustration of Welded Joint Locations Typical of All Categories, of referenced CC-3840 is representative of concrete containment with liner (which, by ASME Section III-2 definition (CC-2121 and D2-II-1000) and function (membrane providing leak-tight integrity), is not a strength element providing structural integrity), it appears to not be fully representative of SCCV containment with metallic components including inner faceplate and outer faceplate, diaphragm plates and headed stud anchors, all of which are strength elements. Further, LTR Table 6-2 does not appear to address outer faceplates and permitted types of welds for each Joint Category (with exception of Category C) and welding qualification.
2. While LTR Section 6.14 references ANSI/AISC 360-16 for design of DP-SC connections, it does not reference ANSI/AISC N690-18, which is currently the only nuclear code addressing SC construction for nuclear facilities and used in conjunction with ANSI/AISC 360-16.
3. LTR Section 6.15, Fabrication and Construction Requirements, does not appear to address dimensional tolerances for SCCV DP-SC modules. Additionally, LTR Section 6.0 does not appear to address quality control and quality assurance requirements (and also applicability of CC-2800) for SCCV consistent with the requirements of 10 CFR 50, Appendix B.
4. Since the DP-SC module components are pressure-retaining strength elements and are thicker unlike the liner, with regard to requirements for Welding Qualification and Rules Governing Making, Examining, and Repairing Welds, respectively, it is unclear ((.....

............-.........-....)).

Request

1. (i) Provide a figure equivalent to ASME Section III-2 Figure CC-3831-1 that is representative of welded joint locations typical of all categories specific to SCCV using DP-SC modules.

Also, provide modified joint category descriptions consistent with terminology for SCCV DP-SC metallic components (inner faceplates, outer faceplates diaphragm plates, headed stud

anchors) and not liner. (ii) Describe permitted welded joint types for each Joint Category and the requirements to be met for welding details and welding qualifications (e.g., CC-4530, CC-4540).

2. Provide justification for not including the nuclear code ANSI/AISC N690-18, endorsed in RG 1.243, for design of DP-SC connections for SCCV; OR include it in LTR Section 6.14.
3. Clarify where the LTR addresses dimensional tolerances, and quality control and quality assurance requirements (and also applicability of CC-2800) for SCCV DP-SC construction.

Address these in LTR Section 6.0 if not addressed.

4. With regard to requirements for Welding Qualification and Rules Governing Making, Examining, and Repairing Welds, respectively, for fabrication of SCCV DP-SC modules, clarify ((.........................-.........-....

..........,.........,............)).

Question 10 RAI 6.22-1

Background

10 CFR 50.55a(g)(4) requires, in part: "Components that are classified as Class MC pressure retaining components and their integral attachments, and components that are classified as Class CC pressure retaining components and their integral attachments, must meet the requirements, except design and access provisions and preservice examination requirements, set forth in Section XI of the ASME BPV Code and addenda that are incorporated by reference in paragraph (a)(1)(ii) of this section subject to the condition listed in paragraph (b)(2)(vi) of this section and the conditions listed in paragraphs (b)(2)(viii) and (ix) of this section, to the extent practical within the limitation of design, geometry, and materials of construction of the components."

As a result of the regulatory audit, GEH proposed a revision to the LTR that states in revised Section 6.22 in part:

" Subsections IWE and IWL of ASME Section XI are used where applicable to SCCV DP-SC modules considering that SCCV inner faceplates (i.e., containment side) are treated similar to metallic liners of Class CC components, diaphragm plates/outer faceplates are treated as integral attachments to metallic liners of Class CC components, and concrete infill as Class CC concrete components. As mentioned in Section 6.1, the SCCV DP-SC modules, including the inner and outer faceplates, diaphragm plates, and concrete infill, are part of the containment pressure boundary."

Issue

1. For the purpose of inservice inspection (ISI) requirements in accordance with ASME Section XI, Subsection IWE, the headed stud anchors which are part of shear connectors

and are integral attachments to both the faceplates supporting composite action for the DP-SC modules and welds appear to be not included in LTR Section 6.22.

2. In accordance with ASME Section III, Division 2, CC-3121, metallic liners shall not be used as a strength element in Class CC containments, and by function the liner serves only as a membrane providing leak-tight integrity to the pressure-retaining and pressure-resisting concrete containment which provides structural integrity. For the SCCV, noting that the LTR credits only the inner faceplate for leak-tightness, since the composite DP-SC section is the pressure-retaining / pressure-resisting component of the SCCV providing structural integrity with both the inner and outer faceplates and their attachments (diaphragm plate, anchors) being strength elements. A liner of Class CC containment is not a strength element but only a leak-tight membrane. Characterizing the inner faceplate similar to a liner of Class CC component is inconsistent with its function. Also, the outer faceplate and their attachments are also subject to ISI pursuant to 10 CFR 50.55a(g)(4). Further, the Subsection IWE program for the BWRX-300 containment would include Class MC components (closure head, penetrations, hatches, etc.) in addition to the DP-SC components. Therefore, consistent with the objective of an ISI program to maintain intended function of providing structural integrity and leak-tight integrity, for the purposes of ISI of SCCV adapting ASME Section XI, Subsection IWE, it would be inappropriate to characterize the SCCV DP-SC pressure-retaining boundary components as liner and integral attachments of Class CC containment, rather than characterizing the SCCV metallic DP-SC modules (inner and outer faceplates, diaphragm plates, headed stud anchors, and all welds) consistent with their function as similar to Class MC pressure-retaining components and their integral attachments. Further, the outer faceplate is not an integral attachment of the inner faceplate as characterized in the LTR.

Request

1. Update the LTR to clearly identify the metallic components of the BWRX-300 SCCV DP-SC modules (inner and outer faceplates, diaphragm plates, headed stud anchors, welds) that will be subject to inservice inspection (ISI) by adapting the ASME Code,Section XI, Subsection IWE, pursuant to 10 CFR 50.55a(g)(4). If any DP-SC metallic components are excluded, justify its exclusion from the ISI program and still meet the requirements of 10 CFR 50.55a(g)(4).
2. Revise the characterization of the DP-SC pressure-retaining / pressure-resisting boundary components of the SCCV for the purposes of inservice inspection in accordance with 10 CFR 50.55a(g)(4) by adapting ASME Section XI, Subsection IWE consistent with their intended functions of providing structural integrity and leak-tight integrity.

Question 11 RAI 7.2-1

Background

LTR Sections 7.2 through 7.3, summarizes the confirmatory NRIC prototype testing, documented in GEH ID 007N0873, Revision 2, NRIC Prototype Test Report [submitted as

- Proprietary (ML23212B129) of GEH Letter M230098 dated July 31, 2023 (ML23212B127)] used to validate the code/proposed equations in the LTR for structural capacity for various limit states of DP-SC structural elements. The acceptance criteria in LTR Sections 7.2.2 through 7.2.5 and results in LTR Sections 7.3.2 through 7.3.5, based on the NRIC Prototype Test Report, document acceptance criteria being met by comparing experimental strengths to calculated design strength or interactions based on code/proposed equations using measured material properties and applying the capacity reduction factor, f (e.g., Rexp/fRcalc-meas 1 and similarly for interaction checks).

For example: For the Out-of-Plane Shear Tests, the acceptance criteria in NRIC Test Report, Section 1.1.1(ii) states: The load carrying capacity of the specimens is equal to or greater than the load associated with the design flexural capacity (f Mn-meas) and design shear strength (f Vn-meas) calculated using ANSI/AISC N690 or ACI 349M code equations, whichever applies to the configuration, and measured material properties along with applicable resistance factors.

Likewise acceptance criteria in NRIC Prototype Test Report Sections 2.1.1, 3.2, 4.2, respectively for biaxial tension tests, in-plane shear tests, and in-plane shear + out-of-plane shear tests (including interaction checks) are based on only respective design strength or capacity (using measured material properties on concrete (compressive) and steel (yield, tensile) and applying strength reduction factors) and not also based on nominal strength (using nominal (specified) material properties and without strength reduction factors) for the generic case.

Issue The NRC staff notes that capacity or strength reduction factors should not be used in calculated strength for comparison against experimental strength (Rexp) for the purpose of validating proposed equations because: (i) a purpose of the test (which is controlled) is to validate the calculated strength using code/proposed equations that are developed empirically and/or analytically; (ii) the capacity or strength reduction factor (f) is applied only in generic design using the validated code/proposed equations to account for uncertainty and variability in material/strength properties and uncertainty in the resistance mechanisms in generic applications, and provide a certain minimum level of design margin in the design and use of the f factor in the test program acceptance criteria essentially eliminates the design margin for strength incorporated in the codes; (iii) f factors in the codes for different limit states (flexure, shear, compression, etc.) are independent (i.e., not derived) from testing; and (iv) for a generic case, design strength based on measured properties (f Rn-meas) can be lower than nominal strength (Rn-nom) using nominal or specified material properties.

While the acceptance criteria of experimental strength being greater than or equal to design strength using measured material properties (and properties derived from that; e.g., Ec, n) and applying strength reduction factor ((f Rn-meas) may be a necessary acceptance criteria for validating the strength equations and the design of the test specimens for the specific test case, this criterion in itself does not appear to be a sufficient acceptance criteria for validating the code or proposed equations in the LTR for generic case for use in the BWRX-300 DP-SC structural elements. This would be provided by a second criteria and a corresponding check of the experimental strength and interaction check that the experimental strength is greater than or equal to the calculated nominal strength or capacity calculated using nominal or specified

material properties (and properties derived from nominal) and without use of the capacity or reduction factor, f, (i.e., Rexp/Rn_nom 1 and similarly for interaction checks).

Further, as a result of the regulatory audit, GEH proposed a revision to the LTR in revised Chapter 7 that, continues to extensively use the term design strength or design capacity where nominal strength or capacity may be intended.

Request

1. Provide information, for all the NRIC Prototype Tests relied upon in the LTR as confirmatory technical basis for the proposed design approach, that demonstrate that a second acceptance criterion of the generic case (that will be used in design) is also validated and met; i.e., the criterion that the experimental strength is greater than or equal to the calculated nominal strength or capacity (and interaction checks, where applicable) based on code or proposed LTR equations using nominal or specified material properties (and derived nominal properties - e.g., Ec, n) and without using the strength reduction factor (i.e.,

Rexp Rn_nom, and required interaction checks) are met.

2. Document the above second criterion and how it was met in the LTR.
3. Revise the LTR to replace or explicitly clarify the terms design strength or design capacity where nominal strength may be intended consistent with code terminology.

OFFICE NRR/DNRL/NLIB/PM NRR/DNRL/NLIB/BC NRR/DEX/ESEB/BC NAME JGlisan MHayes ITseng DATE 01/12/2024 01/12/2024 01/11/2024

Retrieved from "https://kanterella.com/w/index.php?title=ML24033A206&oldid=5526452"