ML23324A404

Enclosure 1 Request for Additional Information

ML23324A404
Person / Time
Site:	07201042
Issue date:	12/06/2023
From:	Storage and Transportation Licensing Branch
To:
Shared Package
ML23324A402	List: ML23324A403 ML23324A404
References
EPID L-2022-LLA-0017, CAC 001028
Download: ML23324A404 (7)

Text

Request for Additional Information (RAI)

Docket No. 72-1042 Certificate of Compliance No. 1042 Amendment No. 4 NUHOMS EOS System

This request identifies additional information needed by the U.S. Nuclear Regulatory Commission (NRC) staff in connection with its review of the application. The NRC staff used NUREG-2215, Standard Review Plan for Spent Fuel Dry Storage Systems and Facilities," in its review of the application.

Each question discusses information needed by the NRC staff to complete its review of the application and to determine whether the applicant has demonstrated compliance with the regulatory requirements of Part 72 of Title 10 of the Code of Federal Regulations (10 CFR).

Structural Evaluation

RAI 4-1: (See enclosure 2)

RAI 4-2: (See enclosure 2)

RAI 4-3: Document in UFSAR section 3 that a 1/16-inch corrosion allowance on the dry shielded canister (DSC) support structural steel was considered for its design. Specifically state in the UFSAR which evaluations consider the corrosion allowance and the justification for how its inclusion produces bounding results. Update the UFSAR to include this information as necessary.

From a review of UFSAR section 3.9.4 and 3.9.8, there is no mention of the 1/16-inch corrosion allowance on the FPS-type DSC support structure. However, UFSAR sections 8.2.1.3 and 8.2.5.6 state that the allowance is considered in the structural property determinations.

This information is necessary to demonstrate compliance with 10 CFR 72.236(b) and (l).

RAI 4-4: (See enclosure 2)

RAI 4-5: (See enclosure 2)

RAI 4-6: (See enclosure 2)

RAI 4-7: (See enclosure 2)

RAI 4-8: (See enclosure 2)

RAI 4-9: (See enclosure 2)

RAI 4-10: (See enclosure 2)

RAI 4-11: (See enclosure 2)

Enclosure 1 RAI 4-12: Address the following items regarding the global structural response from tornado missile impacts for the EOS-HSM-SC presented in UFSAR section 3.9.8.10.6.2, and update the UFSAR as necessary:

a. Justify the difference in artillery shell missile impact load and contact duration between what is shown in UFSAR section 3.9.4.10.6.2.B for the EOS-HSM-RC and that presented in calculation EOS01-0265, Revision 1, for the EOS-HSM-SC.

Confirm that the artillery shell missile loading employed for the EOS-HSM-SC evaluation is bounding.

b. Justify the difference in steel pipe missile impact load and contact duration between what is shown in UFSAR section 3.9.4.10.6.2.C for the EOS-HSM-RC and that presented in calculation EOS01-0265, Revision 1, for the EOS-HSM-SC.

Additionally, it is stated in the UFSAR that a second methodology is employed to determine the impact load and contact duration beyond that presented in UFSAR section 3.9.4.10.6.2.C. Confirm that the steel pipe missile loading employed for the EOS-HSM-SC evaluation is bounding.

c. Verify that the yield resistance and fundamental period of vibration values reported in the UFSAR for the rear shield wall, end shield wall, front base wall and roof global response produce the bounding results for each component. UFSAR section 3.9.8.10.6.2 states that the rear shield wall is idealized as simply-supported plates and the end shield wall, base front wall, and roof are idealized as simply-supported beams. However, calculation EOS01-0265, Revision 1, shows the investigation of several alternate support conditions and lengths.

d. Justify the use of the entire height of shield walls as support points for the determination of the yield resistance and fundamental period of vibration of the shield walls, as described in c.

e. Justify the use of a beam width of 84 inches for the determination of the yield resistance and fundamental period of vibration of the base front wall in calculation EOS01-0265, Revision 1. This width is determined by adding the widths of 2 independent beams which are, in actuality, separated by the circular opening on the front wall. Staff notes that the evaluation based on this combined beam width does not reflect the individual beam responses to a direct missile strike on either the top or bottom portion of the front wall (e.g., above or below the door).

f. Identify that the following components were demonstrated by calculation to undergo shear-controlled failures, thereby limiting the ductility ratio to 1.0 per RG 1.243: front wall, end wall, rear wall, roof, and door.

Calculation EOS01-0265, Revision 1, presents the derivation of missile impact and target ductility parameters for evaluation. For items a to d above, the UFSAR does not currently acknowledge the loading or support condition variations considered in the calculation, nor does it state that the ductility results for each component presented in the UFSAR are bounding. For item f above, the staff notes that calculation EOS01-0265 indicates that a ductility ratio of 1.3 is required for the structural target global response to satisfy ANSI/AISC N690-18 appendix N9 requirements. However, the applicant stated in UFSAR section 3.9.8.10.6.2 that the limiting ductility ratio of 1.0 for shear-controlled failures is employed, in accordance with the guidance in

regulatory guide (RG) 1.243, Revision 0, Safety-Related Steel Structures and Steel-Plate Composite Walls for Other Than Reactor Vessels and Containments.

This information is necessary to demonstrate compliance with 10 CFR 72.236(b) and (l).

RAI 4-13: Reconcile the apparent conflict in methodology between the EOS-HSM-RC and EOS-HSM-SC sliding evaluation for flooding conditions cited in the UFSAR. Update the UFSAR as necessary.

UFSAR section 3.9.8.11 states that stability analyses for the EOS-HSM-SC are performed using the same methodology as those for the EOS-HSM-RC presented in UFSAR section 3.9.7.

However, UFSAR section 3.9.8.11.3 for flood-condition sliding states that a loaded EOS-HSM-SC and two end shield walls were considered for the analysis, while UFSAR section 3.9.7.1.8.2.2 states that only one end shield wall is considered for the EOS-HSM-RC analysis.

The staff notes that EOS-HSM-SC stability analyses presented in calculation EOS01-0268, Revision 1, employs two end shield walls for the flooding condition.

This information is necessary to demonstrate compliance with 10 CFR 72.236(b) and (l).

RAI 4-14: Update the UFSAR to reflect the existing structural analysis of an empty, single EOS-HSM-SC structure (i.e., with no shield walls), placed at the end of an array of loaded HSMs, as a tornado missile barrier.

UFSAR section 1.8.1 indicates that one empty HSM with no shield walls, placed at the end of a loaded array, is an acceptable configuration. This statement addresses the use of one HSM for shielding protection but does not address its adequacy for tornado missile protection of the adjacent loaded HSM. The staff notes that calculation EOS01-0265, Revision 1, contains an evaluation of a single EOS-HSM-SC as a tornado missile barrier, but its adequacy is not explicitly noted in the UFSAR.

This information is necessary to demonstrate compliance with 10 CFR 72.236(b) and (l).

RAI 4-15: Justify the use of the DSC weight of 124 kips employed to check the EOS-HSM-SC axial retainer in section 8.4 of calculation EOS01-0320, Revision 1. Update the UFSAR as necessary.

Section 8.4 of calculation EOS01-0320, Revision 1, employs a DSC weight of 124 kips to determine the resulting shear and flexural design loads for the axial retainer as cited in UFSAR section 3.9.8.10.5. However, it appears that the maximum DSC weight of 135 kips, as cited in Table 1-1 of the UFSAR, would provide a bounding result for the axial retainer seismic design load.

This information is necessary to demonstrate compliance with 10 CFR 72.236(b) and (l).

RAI 4-16: Document in the UFSAR whether the limitation on the required thermal out-of-plane flexural strength is considered in the structural or thermal EOS-HSM-SC FEM analyses, in accordance with section N9.2.4 of the ANSI/AISC N690-18. If this limitation was not employed in FEM analyses, indicate a code exception and provide a justification.

UFSAR section 3.9.8 and calculations EOS-0262, Revision 0, and EOS-0263, Revision 1, do not appear to explicitly state that this limitation was employed per the code requirements.

This information is necessary to demonstrate compliance with 10 CFR 72.236(b) and (l).

RAI 4-17: (See enclosure 2)

RAI 4-18: Provide further justification for the code exception to ANSI/AISC N690 section N9.1.7b(b) regarding the fully-developed front wall opening design and detailing, and demonstrate how the current configuration provides the necessary structural capacities to meet the required demands on the front wall. Address the interior and exterior faces of the front wall of the top HSM section in the justification. This code exception and justification is cited in both UFSAR section 3.9.8.3 and technical specification (TS) section 4.4.4. Update the UFSAR and TS as necessary.

Although some aspects of the code requirements cited in ANSI/AISC N690-18 for fully-developed edges at the perimeter of openings (i.e., N9.1.7.b(b) for large, and N9.1.7a(b) for small) are incorporated in the EOS-HSM-SC design, they are not implemented at the interior and exterior wall faces. Although it is understood that the extent of flange requirements cited sections N9.1.7a(b)(4) is not deemed practical due to geometrical limitations, it appears that the additional 1/4-inch thickness provided for the top front wall faceplate, intended to act as a flange, does not adhere to the requirements of that code section that it be the same thickness of the original 1/2-inch faceplate. Additionally, this increased plate thickness is not provided on both sides of the wall containing the opening, and it is not clear whether the weld between the faceplate and sleeve is a complete joint penetration weld, as required per code section N9.1.a(b)(4). Finally, it does not appear that sections 8.6.1 and 8.7.3 of calculation EOS01-0263, Revision 1, specifically address the load demands and capacities of the SC section configuration and faceplate welds, respectively, around the circumference of the top HSM section opening. The staff notes that demand-to-capacity ratios presented for the front wall in UFSAR Table 3.9.8-3 are increased to account for the presence of the additional faceplate thickness, but the rationale behind this inflation is also not clear.

This information is necessary to demonstrate compliance with 10 CFR 72.236(b) and (l).

Thermal Evaluation

RAI 5-1: Provide a clarification as to the types of fuel assemblies allowed to be transferred or stored under the proposed MHLC-37-1, as described in the proposed Figure 12 (Revision 1) of the TS (Page F-31).

The applicant, in the original Figure 12 (Revision 0) of the TS, included the following statement as part of Note 3: The MLHCis also not qualified for transfer or storage of WE 14x14 and CE 15x15 fuels. This statement was removed from the revised Figure 12 (Revision 1). It is not clear whether the MHLC-37-1 still prohibits the transfer or storage of WE 14x14 and CE 15x15 fuel assemblies. If this prohibition still remains, it is not clear where in the TS this is now specified.

This information is necessary to demonstrate compliance with 10 CFR 72.236(a)

(Errors/Typos/Suggestions)

In section 4.4.12, bottom of page 4-76, last sentence, change compassion to comparison.

In section 4.9.9.4.2, bottom of page 4.9.9-12, last sentence, change 10 or 11 to 12 or 13.

In Enclosure 2 to E-59796, section 2.2 Changes to the NUHOMS EOS System CoC No. 1042 Technical Specifications the description for TS Number 5.5, TS Page 5-9, is incorrect.

Materials Evaluation

RAI 8-1: Identify the safety category of the anodized coating for the 4HA basket. The revised UFSAR section 4.9.9 includes the emissivity requirements for the anodized coating. UFSAR Table 1-2 states that basket type 4HA with anodized aluminum plates is required for heat load zoning configurations with fuel assemblies having decay heats greater than 3.5 kW. However, the anodized coating safety category is not identified in the UFSAR text or in the revised drawings.

This information is needed to satisfy the requirements of 10 CFR 72.236(b) and (f).

RAI 8-2: Provide the properties for ASTM A36 steel used for the construction of the NUHOMS EOS-HSM-SC. UFSAR section 8.2.1.3, EOS-HSM Horizontal Storage Module, states that the EOS-HSM-SC faceplates are constructed from either ASTM A572 Grade 60 steel or ASTM A36 steel. However, the temperature dependent properties of A36 steel were not included in the revisions to the UFSAR.

This information is needed to satisfy the requirements of 10 CFR 72.236(b) and (g).

RAI 8-3: Provide references for the material properties for the materials included in the following UFSAR Tables:

Table 8-37 ASTM A-572 Grade 60 Table 8-38 ASTM A29 Grade 1010 through 1020 Table 8-39 ASTM A706 Grade 60 Table 8-40 ASTM A449 Type 1, <1 in. dia.

Table 8-41 ASTM A449 Type 1, diameters > 1.0 in. to 1 1/2 in

The UFSAR revisions contain additional tables which include the properties of these materials as a function of temperature but do not include references to the source of these material property values.

This information is needed to satisfy the requirements of 10 CFR 72.236(b).

Acceptance Tests and Maintenance Program Evaluation

RAI 12-1: (See enclosure 2)

RAI 12-2: (See enclosure 2)

RAI 12-3: Provide the following additional information for the following items related to EOS-HSM-SC inspection and maintenance:

a. Describe the technical basis for the acceptable width of cracks in EOS-HSM-SC exterior faceplates found during maintenance inspections noted in UFSAR section

10.3.2 and explain how these crack width dimensions relate to and are addressed in the structural analyses presented in UFSAR section 3.9.8.

b. Indicate which sections of ANSI/AISC N690 should be followed for the repairs of cracks beyond acceptable width as directed in UFSAR section 10.3.2.

c. Indicate how the acceptable faceplate corrosion allowance of 1/8-inch considered in the EOS-HSM-SC design and noted in UFSAR section 10.3.2 is planned to be monitored.

Update the UFSAR as required to reflect this information.

Unless a result of an accident condition, the appearance of any crack in the EOS-HSM-SC faceplates or weld regions would seem to be unlikely. A faceplate or weld region crack of any width should prompt a more detailed inspection and performance evaluation of the EOS-HSM-SC component in question, prior to a repair. Corrosion of faceplates should only occur if the coatings are not properly maintained. The areas of the EOS-HSM-SC structure between module components and shield walls, which appear to be inaccessible for inspections, seem to be most susceptible to corrosion due to trapped moisture. The coating maintenance and inspection of all areas of EOS-HSM-SC faceplates are important to assure that they retain their material integrity as a critical part of the structural system.

This information is necessary to demonstrate compliance with 10 CFR 72.236(g) and (l).

Accident Analysis Evaluation

RAI 16-1. Review UFSAR section 12 and TS section 1.1 to confirm that they do not need to be updated for the introduction of the EOS-HSM-SC. See below for some examples of areas where it appears updating may be required:

a. UFSAR, 12.3.2, Earthquake The Cause of Accident section presents the results of the EOS-HSM-RC frequency analysis and design seismic acceleration values. However, the magnitudes of the design seismic acceleration values determined for the EOS-HSM-SC, as presented in UFSAR Table 3.9.8-2 appear to exceed those cited for the EOS-HSM-RC.

b. UFSAR, 12.3.3, Tornado Wind and Tornado Missile Effect on EOS-HSM" The Accident Analysis section states that the adequacy of the EOS-HSM to resist tornado missile loads is addressed in appendix 3.9.7. Although this statement is correct, it appears that appendix 3.9.8 should also be cited, as the local and global structural responses of the EOS-HSM-SC to missile strikes is quite different than that of the EOS-HSM-RC, as is the acceptance criteria for each.

c. UFSAR, 12.3.7, Lightning

Verify that the statements presented in UFSAR section 12.3.7 regarding lightning effects are still applicable to the new EOS-HSM-SC. As all exterior surfaces of the EOS-HSM-SC are metallic, and the EOS01-3300-SAR, Revision 0C, drawings do not appear to introduce any lightning protection or electrical isolation system, verify that a lightning strike of an EOS-HSM-SC module is not expected to result in a new accident event to the DSC or EOS-HSM-SC.

d. TS, 1.1, Definitions

The entry associated with Horizontal Storage Module (HSM) describes the HSM as a reinforced concrete structure, and states that HSM, when used in the TS, applies to both the EOS-HSM and HSM-MX. The application adds a new steel composite HSM (EOS-HSM-SC) and renames the previous EOS-HSM to a reinforced concrete HSM (EOS-HSM-RC). The definition should clarify that the term EOS-HSM used without distinction refers to the EOS-HSM-RC, the HSM-MX, and the new EOS-HSM-SC.

This information is necessary to demonstrate compliance with 10 CFR 72.236(b) and (l).