ML23005A233
| ML23005A233 | |
| Person / Time | |
|---|---|
| Site: | 07201042 |
| Issue date: | 01/30/2023 |
| From: | Storage and Transportation Licensing Branch |
| To: | TN Americas LLC |
| Shared Package | |
| ML23005A231 | List: |
| References | |
| 001028 | |
| Download: ML23005A233 (1) | |
Text
Request for Supplemental Information (non-proprietary)
By letter dated September 29, 2022, TN Americas LLC submitted to the U.S. Nuclear Regulatory Commission (NRC) an application for Certificate of Compliance (CoC) No. 1042, Amendment No. 4 to the NUHOMS EOS System, pursuant to the requirements of Part 72 of Title 10 of the Code of Federal Regulations (10 CFR Part 72).
This request for supplemental information (RSI) identifies additional information needed by the NRC staff in connection with its review of this amendment application. Each RSI below describes information needed by the staff to complete its acceptance review determination of the subject application. In addition, the staff has noted several observations, which may result in a request for additional information should the application be accepted for docketing.
Structural RSIs and Observations
RSI 3-1 (Proprietary): See enclosure 2
RSI 3-2: Provide descriptions of the basic installed configurations of an EOS-HSM-SC, e.g.,
single, one-row array, or two-row array that are documented in the safety analysis report (SAR).
Indicate in the SAR section 3.9.8 which HSM-SC configuration is being evaluated for each structural compliance check, noting whether that configuration bounds all possible configurations and a rationale behind these statements.
SAR and technical specification (TS) sections provide seemingly conflicting information regarding the expected installation configuration. This conflict creates doubt as to whether the most conservative configuration has been evaluated. A list of noted general conflicts follows: 1)
TS sections 4.5.1 and 5.1.2.b only mention rear shield wall, 2) SAR section 1.1 mentions rear and end shear walls, but also states that empty interior modules can be employed in lieu of shield walls, 3) SAR section 1.2.1.3 mentions rear and end walls, but also states that end walls will be employed between modules, 4) SAR section 3.9.8.1 mentions rear and end walls.
Furthermore, the stability analyses, (e.g., SAR sections 2.3.4, 3.6.2 and 3.9.7), seem to consider several different variations: a) one end wall is present, b) one end wall is present and reevaluation is performed omitting it, and c) end and rear walls are present.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
RSI 3-3: Identify which portions of Regulatory Guide 1.243, Rev. 0 (RG) were considered in the design of the HSM-SC and update the SAR for these citations. For example, justify the use of design load combinations from ANS 57.9-84 in lieu of those prescribed in ANSI/AISC N690-18 for the HSM-SC, documenting the rationale in technical specification (TS) section 4.4.4.
SAR section 2.1.2 indicates that the HSM-SC is designed to ANSI/AISC N690-18 Code, and section 2.4.2.2 indicates that any exceptions taken to the Code are indicated in TS section 4.4.4. However, SAR section 2.4.2.2 states that load combinations in ANS 57.9-84 are employed for design, as shown in table 2-7, which is a Code exception to ANSI/AISC N690-18 design requirements and is not cited in TS section 4.4.4. NUREG-2215 Section 4.5.4 provides guidance that the analysis load combinations should be consistent with the design code requirements.
Enclosure 1 The load combinations presented in ANS 57.9-84 are in alignment with the American Concrete Institute codes for reinforced concrete (i.e., 318 and 349), whereas the load combinations prescribed in ANSI/AISC N690-18 are intended specifically for steel-plate composite (SC) design, as modified by RG 1.243, Rev. 0.
The design criteria in SAR section 3.9.8.3 states that the guidelines of RG 1.243 were considered, but the RG is not cited in any other portion of the SAR. It is also not clear whether the conditions applied by the staff in section C of the RG are observed.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
RSI 3-4 (Proprietary): See enclosure 2
RSI 3-5: Identify the basis for the live load of 200 psf applied to the HSM-SC roof, as cited in SAR section 3.9.8.7 (refers to section 3.9.4.7 and table 3.9.4-4) and advise whether it is used in the live load case employed in all load combinations for structural analysis and stability evaluations. Update the SAR as necessary to document what magnitude of live load is employed for the various structural and stability evaluations.
SAR table 3.9.4-4 indicates the 200 psf load includes 110 psf snow and ice load, as cited in SAR section 2.3.5 and TS section 4.5.3. This 110 psf snow load is identified as the 100-year roof snow load, specified for most areas of the continental United States for an unheated structure. It is unclear to staff how the magnitude of the remaining 90 psf roof live load was determined. Although the guidance in table 4-2 of NUREG-2215 indicates that snow be included in the live load case, the ANSI/AISC N690 section NB2.5 load definitions and combinations differ: snow and roof live load are not only mutually exclusive when included in load combinations, but also have a lower load factor applied than live load effects defined in code section NB2.1. Additionally, the staff is concerned that this amplified gravitational live load in all load combinations may unconservatively counteract uplift, overturning, or sliding evaluations that are presented throughout the SAR. NUREG-2215 Section 4.5.4 provides guidance that the analysis load combinations be consistent with the design code requirements. This additional information is required to proceed with the review of the structural adequacy and stability evaluation results.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
RSI 3-6: Provide stability analysis information for the NUHOMS EOS HSM-SC and document in the SAR.
SAR section 3.9.8.11 addresses the stability analyses for tornado wind and missile impact, flood, seismic, and interaction with adjacent horizontal storage modules. The description of the stability analyses in this section references a corresponding analysis described in SAR section 3.9.7 for the NUHOMS EOS HSM-RC, often simply stating a resulting factor of safety for each analysis or that the HMS-RC results are bounding. Referencing the previous analysis may be sufficient to describe certain aspects of the analysis, such as the methodology, if they are identical to those used to analyze the HSM-SC. However, this approach does not highlight how aspects of the analysis that are unique to the HSM-SC (e.g., horizontal storage module (HSM) configuration and self-weight) are considered. It also does not document the numerical analysis results that form the basis of the reported factor of safety for each loading condition.
2 The staff notes that the design basis tornado wind and missile evaluation results presented in SAR section 3.9.8.11.2 show sliding occurring for a single HSM-SC. SAR section 3.9.8.11.5 states that the results are conservative when the interaction of adjacent modules is considered.
Provide justification for not meeting the guidance provided in table 4-3 of NUREG-2215, which requires a safety factor of 1.1, and how this safety factor is met with a multi-module configuration.
SAR sections 2.3.4 and 3.9.8.9 reference CoC No. 1029 (for the Advanced NUHOMS Horizontal Modular Storage System) as the basis for the stability evaluation methodology employed for the HSM-SC dynamic analyses. The methodology is not easily identifiable by external reference and its content should appear in this SAR for configuration control purposes.
The information in SAR section 3.9.8.11 is insufficient for the staff to begin its review of the stability of the HSM-SC. The staff notes that section 4.5.4.1 of NUREG-2215 discusses the information necessary for the review of hand calculations like those typically used for stability analyses.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
RSI 3-7 (Proprietary): See enclosure 2
RSI 3-8: Provide information to support the HSM-SC global structural response to missile effects in SAR section 3.9.8.10.6.2, as follows:
a) Provide additional structural component input information, i.e., thickness and length.
b) Provide the rationale behind modifying the idealization of the HSM-SC end walls from a simply-supported plate model in SAR section 3.9.4.10.6.2 to a simply-supported beam in section 3.9.8.10.6.2.
c) Provide a summary of resulting ductility ratios for each component evaluated.
d) Clearly document in the appropriate sections of the SAR whether credit is taken for the presence of shield walls acting as missile barriers when evaluating the contiguous HSM-SC overpack structure for compliance with codes and regulations for missile loading effects.
e) Provide SAR Reference 3.9.8-12: Bechtel Corporation Design Guide Number C-2.45 for Design of Structures for Tornado Missile Impact, revision 0, April 1982.
The global structural analysis for tornado missile effects in SAR section 3.9.8.10.6.2 relies on single degree-of-freedom response charts and methodology from the cited reference to determine ductility ratios for various structural components of the HSM-SC. The SAR description in this section points to section 3.9.4.10.6.2 for a description of the methodology, which does not identify the input parameters such as thicknesses or lengths of the structural components being considered in the evaluation. Thus, it is unclear whether the HSM-SC evaluation is based on the end and rear shield walls, or those of the contiguous HSM-SC overpack. Section 2.4.2.1 of Ingecid Calculation 00624IT004, Rev. 0, (included in application 2) states that all HSM-SC walls except the front wall are considered as interior (as defined by the Code) due to the presence of shield walls. This statement implies that the majority of the contiguous HSM-SC walls are not affected by missile impacts, an assumption that was not found to be clearly stated in the body of the SAR. In either case, no rationale is provided for the difference in the end wall support conditions between the HSM-RC and HSM-SC sections, or why the magnitude of the tabulated results is so disparate. The resulting ductility ratios for each HSM-SC component evaluated are not presented in SAR section 3.9.8.10.6.2, thus it is not possible to verify that they are within acceptable Code-prescribed limits. The staff
3 notes that section 4.5.4.1 of NUREG-2215 discusses the information necessary for the review of hand calculations like those employed to determine component ductility ratios. This additional information, as well as a copy of the cited reference, are required to proceed with the review of the HSM-SC global structural response from missile effects.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
RSI 3-9 (Proprietary): See enclosure 2
RSI 3-10: Provide information for the determination of structural acceptability of the important to safety (ITS) connecting items of the HSM-SC, including vertical rods, roof connection angle and bolts, and connections bolts for door, shield walls, and outlet vent cover (OVC), as follows:
a) Identify materials, design codes, and design load combinations for each item.
b) Provide bounding structural design load demands resulting from design load combinations for each component being evaluated.
c) Provide the structural capacities per the applicable design code.
d) Provide demand-to-capacity ratios for all connection components.
The staff notes that the materials specifications of some of the listed items are included in SAR table 8-2. It is also noted that demand-to-capacity ratios for the heat shield connectors are reported in SAR section 3.9.8.10.4, however, no indication of the design code, material strength or load combinations considered is provided. The information in SAR section 3.9.8 is insufficient for the staff to begin its review of the HSM-SC.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
RSI 3-11: Provide information in the SAR for the HSM-SC heat shield structural adequacy check, including determination of associated in-structure response spectra (ISRS).
SAR section 3.9.8.10.4 addresses the heat shield design for the HSM-SC, referring to HSM-RC section 3.9.4.10.4, stating that the design is identical. However, SAR section 3.9.8.9 explains that a modal time history analysis of the HSM-SC is performed to obtain ISRS for the heat shield support points. This statement implies that different ISRS than those for the heat shields of the HSM-RC, as presented in figures 3.9.4-16 to -21, are employed to determine the response of the heat shield plates and support bolts. Based on the resulting heat shield plate and bolt results presented in SAR section 3.9.8.10.4, it appears that the resulting load demands are in fact different than those for the HSM-RC. Additionally, the design code, materials and load combinations employed for the structural adequacy check of the plates and bolts are not identified in the SAR. The information in SAR section 3.9.8.10.4 is insufficient for the staff to begin its review of the HSM-SC heat shields.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
RSI 3-12: Provide information in the SAR for the HSM-SC dry shielded canister (DSC) support structure analysis and axial restraint results.
SAR sections 3.9.8.10.2 and 3.9.8.10.5 address the DSC support structure and axial restraint, respectively. SAR section 3.9.8.10.2 states that the HSM-SC DSC structure is identical to that of the HSM-FPS-RC presented in SAR section 3.9.4.10.2, also referring to the applicable results tables employed in that evaluation. Cite which length of the HSM-FPS-RC in table 3.9.4-17a corresponds to the HSM-SC. Upon review of SAR section 3.9.4.10.2, the applicable design
4 code is stated, however the load cases, load combinations and materials are not. A demand-to-capacity (D/C) ratio for the HSM-SC stop plate is said to be different than the values presented for the HSM-FPS-RC, per load combination C4, but this load combination is not identified, and it is not explicitly explained why the D/C ratio is different. Similarly, SAR section 3.9.8.10.5 states that the HSM-SC DSC axial restraint is identical to that of the HSM-RC presented in SAR section 3.9.4.10.5. No design code, material properties, or load combinations, or analysis results are cited in either SAR section as the basis for the applied loads or load capacity. The information in SAR sections 3.9.8.10.2 and 3.9.8.10.5 are insufficient for the staff to begin its review of the HSM-SC DSC support structure and axial restraint.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
Observation 3-1 (Proprietary): See enclosure 2
Observation 3-2 (Proprietary): See enclosure 2
Observation 3-3: Justify why the thermal expansion evaluation for the HSM-RC heat shields are applicable to those for the HSM-SC, as stated in SAR section SAR 3.9.8.10.4.
The HSM-RC SAR section 3.9.4.10.4 states that no thermal stress will be induced in the heat shield panels as the presence of slotted holes allow free thermal growth. However, no slotted holes in the HSM-SC heat shields are shown on Sheet 5 of 17 of Dwg. EOS01-3300-SAR.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
Observation 3-4: Justify how radial thermal growth of the HSM door is not constrained as described in SAR section SAR 3.9.8.10.3, as well as why the door support bolt evaluation presented in HSM-RC SAR section 3.9.4.10.3 and based on the ACI 349 Code, is applicable.
Although not specifically identified on the Dwg. EOS01-3300-SAR, it is assumed that for the HMS-SC the four door attachment bolts interface with the front wall via an embedded coupling device, similar to those shown in sections A, B and C of Dwg. Sht. 3. The attachment bolt embedment detail for the SC door differs from that shown in the EOS01-3000-SAR, Rev. 4 drawing set. Provide evidence that the structural bolt embedment capacities stated in SAR section 3.9.4.10.3 are still applicable or provide the Code basis for any new capacities.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
Observation 3-5 (Proprietary): See enclosure 2
Observation 3-6 (Proprietary): See enclosure 2
Observation 3-7: Provide further technical justification in TS section 4.4.4 for the use of faceplate material for the exterior door and outlet vent cover (OVC) that has a yield strength of less than the minimum of 50 ksi required by code section N9.1.1(d).
The ANSI/AISC N690-18 code commentary section N9.1.1(d) provides the explanation that the minimum yield strength of 50 ksi is specified to avoid premature yielding from concrete casting and thermally-induced stresses.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
5 Observation 3-8: Justify the applicability of appendix N9 of the ANSI/AISC N690-18 code for the design of the roof and OVC, as they are not being employed as walls for the HSM-SC.
From an initial review of the code by staff it does not appear that the cited code appendix, titled Steel-Plate Composite (SC) Walls, extends to the design of horizontally-oriented structural elements.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
Observation 3-9: Justify the applicability of appendix N9 of the ANSI/AISC N690-18 code for the design of the walls of the HSM-SC, as they are not positively anchored at their base to the supporting basemat, in the middle where they are split for modularity purposes, nor at their top to the roof.
From an initial review of the code by staff, it does not appear that the code appendix addresses these non-continuous support conditions.
This information is necessary to demonstrate compliance with 10 CFR 72.236(b), (d) and (l).
Materials RSIs and Observation
RSI 8-1: Provide material properties for ASTM A572 Gr. 65 cited as an optional material for the EOS-DSC support structure.
The applicant is adding an option of using ASTM A572 Gr. 65 for the flat plate support for EOS-DSC support structure. The staff was not able to locate the material properties for ASTM A572 Gr. 65 in the application.
This information is needed to satisfy the requirements of 10 CFR 72.236(b).
RSI 8-2: Provide the applicable standard(s) that will be used for the anodized aluminum for the 4H and 4HA basket types.
The applicant provided a minimum emissivity value for anodized aluminum to promote heat transfer. The staff notes that aluminum can be anodized using various standards and the resultant emissivity values for anodized aluminum is typically dependent on the thickness of the anodized layer. The application does not indicate which standard or standards will be used to consistently obtain emissivity values that meet or exceed the required minimum value.
This information is needed to satisfy the requirements of 10 CFR 72.236(b) and (f).
Observation 8-1: Clarify whether an anodized coating on aluminum is required for the 4H and 4HA basket types.
The staff notes that page 1-10, Rev 4, 06/22, states that the aluminum basket plates may be anodized to allow for storage of fuels with decay heats greater than the specific kilowatt (kW) value. However, on page 1-4 and 1-35, a Note on the drawing states anodizing is required for aluminum plates for basket types that hold fuels with decay heats greater than the specified kW value.
This information is needed to satisfy the requirements of 10 CFR 72.236(b) and (f).
6