ML22355A219
| ML22355A219 | |
| Person / Time | |
|---|---|
| Site: | 07201042 |
| Issue date: | 12/21/2022 |
| From: | Narayanan P Orano TN Americas, TN Americas LLC |
| To: | Office of Nuclear Material Safety and Safeguards, Document Control Desk |
| Shared Package | |
| ML22355A218 | List: |
| References | |
| E-61866, CAC 001028, EPID L-2021-LLA-0055 | |
| Download: ML22355A219 (1) | |
Text
Enclosures transmitted herein contain SUNSI. When separated from enclosures, this transmittal document is decontrolled.
Columbia Office 7160 Riverwood Drive Columbia, MD 21046 Tel: (410) 910-6900
@Orano_USA December 21, 2023 E-61866 U. S. Nuclear Regulatory Commission Attn: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852
Subject:
Application for Amendment 3 to NUHOMS EOS Certificate of Compliance No. 1042, Revision 11 (Docket 72-1042, CAC No.
001028, EPID: L-2021-LLA-0055) - Response to Request for Additional Information (New Scope Addition #3 - ASME NOG-1 Exceptions) and Clarifications Regarding Annulus Water
Reference:
[1] Letter from Christian Jacobs to Prakash Narayanan, TN Americas LLC Application for Certificate of Compliance No. 1042, Amendment No. 3, to NUHOMS EOS System (Docket No. 72-1042, CAC No. 001028, EPID: L-2021-LLA-0055) - Request for Additional Information (New Scope Addition #3 - ASME NOG-1 Exceptions),
dated December 8, 2022
[2] Letter E-61743 from Prakash Narayanan, Application for Amendment 3 to NUHOMS EOS Certificate of Compliance No.
1042, Revision 10 (Docket 72-1042, CAC No. 001028, EPID: L-2021-LLA-0055) - Additional Information regarding ASME NOG-1 Compliance and the Matrix Loading Crane (MX-LC), dated November 14, 2022
[3] Letter E-61137 from Prakash Narayanan, Application for Amendment 3 to NUHOMS EOS Certificate of Compliance No.
1042, Revision 7 (Docket 72-1042, CAC No. 001028, EPID: L-2021-LLA-0055) - Clarifications Regarding Annulus Water, MX-LC Alignment, and Seismic Damping Values, dated October 31, 2022
Document Control Desk E-61866 Page 2 of 3
[4] Letter E-61399 from Prakash Narayanan, Application for Amendment 3 to NUHOMS EOS Certificate of Compliance No. 1042, Revision 8 (Docket 72-1042, CAC No. 001028, EPID: L-2021-LLA-0055) - ASME NOG-1 Compliance and the Matrix Loading Crane (MX-LC), dated September 30, 2022
[5] Letter E-58840 from Prakash Narayanan, Application for Amendment 3 to NUHOMS EOS Certificate of Compliance No. 1042, Revision 1 (Docket 72-1042, CAC No. 001028, EPID: L-2021-LLA-0055) - Response to Request for Supplemental Information (New Scope) and Revised Responses to Request for Additional Information, dated June 23, 2021
[6] Letter E-58329 from Prakash Narayanan, Application for Amendment 3 to NUHOMS EOS Certificate of Compliance No. 1042, Revision 0 (Docket 72-1042), dated March 31, 2021 This submittal provides responses to the Request for Additional Information (RAI) forwarded by Reference [1]. This submittal also is a supplement to Reference [3] and provides further clarification regarding the approach to maintaining water in the annulus between the dry shielded canister (DSC) and the transfer cask (TC) during loading operations. The item was initially addressed in TN Americas LLCs (TN) response to Observation 4-9, in Reference [5].
As follow-up to Reference [3], the NRC and TN held a conference call on December 13, 2022,
[ML22348A117], for the purpose of further discussions and clarification from the contents included in Reference [3]. Based on these interactions with the NRC, TN is providing further clarification to address this issue.
The submittal contains the following enclosures:
- provides the RAI responses. Each RAI response has a section stating the impact of the response on the updated final safety analysis report (UFSAR), indicating which sections, tables, etc., have been changed.
- provides the additional information in response to the clarification discussions from the conference call on December 13, 2022.
- provides a listing of changed UFSAR pages resulting from this Revision 11 to the application for Amendment 3.
- provides a proprietary version of the UFSAR changed pages associated with this Revision 11 to the application for Amendment 3. The changed pages include a footer annotated as 72-1042 Amendment 3, Revision 11, January 2023, with changes indicated by italicized text and revision bars. The changes are further annotated with gray shading or a gray box enclosing an added section, as well as a footer to distinguish the Amendment 3, Revision 11 changes from previous Amendment 3 changes. Enclosure 6 provides a public version of these pages.
- provides the Chapter 9 pages from the UFSAR Revision 4 update mentioned in Enclosure 3.
- provides supporting information associated with Enclosure 2. Since Enclosure 8 contains entirely proprietary information, no public version is provided.
Document Control Desk E-61866 Page 3 of 3 Certain portions of this submittal include proprietary information, which may not be used for any purpose other than to support the NRC staffs review of the application. In accordance with 10 CFR 2.390, TN is providing an affidavit (Enclosure 1), specifically requesting that this proprietary information be withheld from public disclosure.
Should the NRC staff require additional information to support review of this application, please do not hesitate to contact Mr. Glenn Mathues at 410-910-6538, or by email at Glenn.Mathues@orano.group.
Sincerely, Prakash Narayanan Chief Technical Officer cc:
Chris Jacobs (NRC), Senior Project Manager, Storage and Transportation Licensing Branch Division of Fuel Management
Enclosures:
- 1. Affidavit Pursuant to 10 CFR 2.390
- 2. RAIs and Responses
- 3. Additional Information Regarding Clarification Question
- 8. Supporting Information File for RAI 3 (Proprietary)
TN Americas. LLC State of Maryla'hd County of Howard
)
)--. ss.
)
AFFIDAVIT PURSUANT TO 10 CFR 2.390 Enclosure l to E-61866 I, Prakash Narayanan, depose and say that I am Chief Technical Officer of TN Americas LLC, duly authorized to execute this affidavit, and have reviewed or caused to have reviewed the information that is identified as proprietary and referenced in the paragraph immediately below. I am submitting this affidavit in conformance with the provisions of 10 CFR 2.390 of the Commission's regulations for withholding this information.
The information for which proprietary treatment is sought is contained in the following enclosures, as listed below:
- - Portions of certain updated final safety analysis report (UFSAR) chapters
- - Supporting Information File for RAT 3 These documents have been appropriately designated as proprietary.
I have personal knowledge of the criteria and procedures utilized by TN Americas LLC in designating information as a trade secret, privileged or as confidential commercial or financial information.
Pursuant to the provisions of paragraph (b) (4) of Section 2.390 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure, included in the above referenced document, should be withheld.
- 1) The information sought to be withheld from public disclosure involves portions of the UFSAR and a maintenance procedure, all related to the design of the NUHOMS EOS System, specifically the MX-LC design details, which are owned and have been held in confidence by TN Americas LLC.
- 2) The information is of a type customarily held in confidence by TN Americas LLC, and not customarily disclosed to the public. TN Americas LLC has a rational basis for determining the types of information customarily held in confidence by it.
- 3) Public disclosure of the information is likely to cause substantial harm to the competitive position of TN Americas LLC, because the information consists of descriptions of the design and analysis of dry spent fuel storage systems, the application of which provide a competitive economic advantage. The availability of such information to competitors would enable them to modify their product to better compete with TN Americas LLC, take marketing or other actions to improve their product's position or impair the position of TN Americas LLC's product, and avoid developing similar data and analyses in support of their processes, methods or apparatus.
Further the deponent sayeth not.
Prakash Narayanan Chief Technical Officer Subscribed and sworn before me this f'i~ay of December 2022.
~
My Commission Expires / 0 I S I.:Z5 Page 1 of l KHYNESYA TAYLOR Notary Public Howard County Maryland My Commission Expires Oct. 5, 2025
RAIs and Responses to E-61866 Page 1 of 3
RAI 1
Include the installation of the gantry box wheel chocks in the operating procedures in the Safety Analysis Report (SAR) section A.9.
It appears that wheel chocks are relied on in analyses of the MX-LC (e.g., the assumed boundary conditions for the seismic stability analysis in Calculation No. 41041-0205) and SAR statements (e.g., SAR section A.2.1.4.2.1.4 states, For these seismic analyses, a pair of wheel chocks is provided for each of the four gantry boxes to restrain the gantry lower boom from sliding under seismic loading.). However, the operating procedures for transferring the dry shielded canister (DSC) to the HSM-MX in SAR section 9.1 do not include the installation of the gantry box wheel chocks.
This information is needed to determine compliance with the regulatory requirements in Title 10 of the Code of Federal Regulations (10 CFR) Section 72.150.
Response to RAI 1:
To support the seismic stability of the MX-LC, the installation of wheel chocks on the MX-LC gantry boxes is credited to restrain the MX-LC from sliding along the rails under seismic loading.
The wheel chocks are required to be installed and active under two conditions,
- 1. When handling the loaded TC/DSC above the applicable lift height restriction of Technical Specification (TS) 5.2.1, and
- 2. While the DSC is being inserted into or retracted from the HSM-MX.
When the MX-LC is traveling along the rails with the loaded TC/DSC, sliding of the MX-LC may occur in a seismic event. However, this is acceptable since the MX-LC is not required to be seismically qualified in this configuration where the loaded TC/DSC remains below the lift height restriction of Technical Specification (TS) 5.2.1.
The operational sequences described in UFSAR section A.9.1.6 DSC Transfer to the HSM-MX and UFSAR Section A.9.2.1 DSC Retrieval from the HSM-MX are revised to incorporate the applicable steps for installation and removal of the wheel chocks. Other related sequences are clarified accordingly.
Impact:
UFSAR sections A.9.1.6 and A.9.2.1 have been revised as described in the response.
RAIs and Responses to E-61866 Page 2 of 3
RAI 2
Describe the approach that ensures the DSC is in an analyzed configuration after it is lifted with the MX-LC and prior to the installation of the gantry box wheel chocks.
It appears that the wheel chocks are relied upon to restrain the MX-LC in the analyses of lateral loads and that the DSC lifted by the MX-LC is in an unanalyzed configuration before installing the wheel chocks. The following are examples of approaches that could address this condition:
(1) describe how this configuration without wheel chocks is bounded by the existing analyses; (2) clarify if the emergency brakes for the for the gantries are automatically applied, satisfy the seismic design requirements for single-failure-proof lifting devices in section 2.5 of NUREG-0554, and satisfy the boundary condition assumptions of the analyses or provide such emergency brakes; (3) limit the lifting height during these steps of the procedures to less than the maximum lift height of 65 inches for non-single-failure-proof lifting devices; or (4) analyze the MX-LC without relying on the use of the gantry box wheel chocks.
This information is needed to determine compliance with the regulatory requirements in 10 CFR 72.236(l).
Response to RAI 2:
The approach that ensures the DSC is in an analyzed configuration is based on Item (3) in the RAI description above, where without the wheel chocks installed on the MX-LC, the lift height of the loaded TC/DSC is required to remain below the lift height restriction of Technical Specification (TS) 5.2.1.
The wheel chocks are installed when handling the loaded TC/DSC above the applicable lift height restriction of TS 5.2.1, and while the DSC is being inserted into or retracted from the HSM-MX.
The description for the structural design of the MX-LC provided in UFSAR Section A.2.1.4.2.1.4 Functional Specification and Design Criteria has been revised to clarify when the wheel chocks are required to be installed. An unrelated typographical error has also been corrected in UFSAR Section A.2.1.4.2.1.1.
Impact:
UFSAR Sections A.2.1.4.2.1.1 and A.2.1.4.2.1.4 have been revised as described in the response.
RAIs and Responses to E-61866 Page 3 of 3
RAI 3
Provide a summary description of how the maintenance and testing for the MX-LC satisfies the intent of paragraph 5.1.1(6) of NUREG-0612 and sections 7 through 9 of NUREG-0554 and update the SAR as necessary.
SAR sections A.1.2.1.4.2.1.10 through A.1.2.1.4.2.1.15 describe the testing and maintenance of the MX-LC. While the SAR describes the maintenance and testing activities, it does not describe the frequency and acceptance criteria associated with the activities. The staff notes that this information may currently be in the operating and maintenance manuals mentioned in SAR section A.2.1.4.2.1.14.
This information is needed to determine compliance with the regulatory requirements in 10 CFR 72.146, 72.150, and 72.162.
Response to RAI 3:
Regarding the reference to NUREG-0554 for maintenance and testing activities, the MX-LC is not licensed to NUREG-0554, but rather to ASME NOG-1. Regarding the frequency of maintenance and testing activities, NUREG-0612, paragraph 5.1.1(6) states, in part, for cranes having limited usage, that the inspections, tests, and maintenance should be performed prior to their use.
The MX-LC is not in continuous operation. As stated in UFSAR Sections A.2.1.4.2.1.4 and A.2.1.4.2.1.13, the MX-LC is operated intermittently during loading campaigns at nuclear power plant sites. When not in use, the MX-LC is laid-up in a partially disassembled condition. When shipped between power plant sites, the MX-LC is completely disassembled and packaged for transportation in a fashion similar to that used during initial shipment from the manufacturer.
Therefore, maintenance and testing activities are performed on a per use basis for each loading campaign.
After initial assembly at a power plant site, or after reassembly from storage, a no-load test is performed as described in UFSAR Section A.2.1.4.2.1.12 in accordance with ASME NOG-1, paragraphs 7250 and 7421. The crane is taken through the full range of lifting heights, the full range of bridge and trolley travel, and over the full range of lift and travel speeds. Mechanical, electrical and control functions of the MX-LC equipment are verified for proper operation.
Functional tests of the MX-LC are performed using the empty transfer cask to verify the proper functioning of safety devices and performance of the crane as designed. Maintenance is also performed on a per use basis and during storage in accordance with the manufacturers recommendations, and as specified in the applicable maintenance procedure NUH-MX-M-001 (included as Enclosure 8).
Impact:
No change as a result of this RAI.
to E-61866 Additional Information Regarding Clarification Question Page 1 of 1 As follow-up to the clarification call with the NRC on December 13, 2022, TN is providing the following additional information.
Clarification Question #1 and Reference to UFSAR Section 9.1.2:
In the response to Part 1B to Thermal Clarification #1, submitted to the Nuclear Regulatory Commission on 10/31/2022, TN indicated that Step 17 of Section 9.1.2 of the updated final safety analysis report (UFSAR) was updated to limit the lowest internal pressure within the DSC, during vacuum drying operations, to 0.75 Torr. Section 9.1.2 was incorrectly referenced; the reference should have been Section 9.1.3, Step 17. Step 24 was also edited in Section 9.1.3 regarding the 0.75 Torr. The change to these two steps in Chapter 9 was incorporated into UFSAR Revision 4, submitted on June 17, 2022, Accession Number ML22168A017. A copy of the two associated pages is included in Enclosure 7, for information. The changes to these two steps were indicated for each by a 72.48 box in the righthand margin.
Impact:
None Clarification Question #1 and Reference to Helium Introduction In response to Part 1A to Thermal Clarification Question #1 submitted to the Nuclear Regulatory Commission on 10/31/2022, TN indicated that helium was introduced in a step-wise manner for DSC #009 at the Davis-Besse Nuclear Power Station to mitigate boiling and maintain the water level within the TC/DSC annulus. Steps 18 and 25 of UFSAR Section 9.1.3 have been updated to include similar changes for all helium fill operations.
Impact:
UFSAR Section 9.1.3 has been revised as described above.
Other In the December 13th call, NRC staff identified that, within UFSAR Section 4.5.11.1, TN referred to Section 9.1.2. This is incorrect and should have been Section 9.1.3. This edit to UFSAR Section 4.5.11.1 has been corrected.
Impact:
UFSAR Section 4.5.11.1 has been revised as described above.
to E-61866 List of UFSAR Pages Involved in CoC 1042 Amendment 3, Revision 11 Page 1 of 1 UFSAR Pages 4-106 9-10 9-11 A.2-4 A.2-9 A.9-3 A.9-4 A.9-7 A.9-8 to E-61866 CoC 1042 Amendment 3, Revision 11 UFSAR Changed Pages Withheld Pursuant to 10 CFR 2.390 to E-61866 CoC 1042 Amendment 3, Revision 11 UFSAR Changed Pages (Public)
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 December 2022 Revision 11 72-1042 Amendment 3 Page 4-106 Impact of Helium Injection on TC/DSC Annulus Water Temperature Once the vacuum drying requirements per TS LCO 3.1.1 are satisfied, the DSC is pressurized up to 23 psig with helium as noted in Step 19 of Section 9.1.3 which increases the TC/DSC annulus water temperature.
All Indicated Changes are in Support of Enclosure 3
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 December 2022 Revision 11 72-1042 Amendment 3 Page 9-10 CAUTION: For the EOS-TC108, verify the neutron shield is filled with water and continuously monitor water in the neutron shield during the first five minutes of DSC cavity draining as specified in Section 5.1.2.e of the Technical Specifications [9-5].
- 14. Attach the VDS, if necessary, to vacuum dry the canister through the drain port and attach the VDS to a helium supply.
- 15. Install an appropriate fitting to isolate the vent port to allow vacuum drying of the DSC.
- 16. Connect a hose from the discharge side of the VDS to the plant's radioactive waste system or spent fuel pool.
Note: Proceed cautiously when evacuating the DSC to avoid freezing consequences.
- 17. Open the valve on the suction side of the pump, start the VDS and draw a vacuum on the DSC cavity. The cavity pressure should be reduced in steps of approximately 100 mm Hg, 50 mm Hg, 25 mm Hg, 15 mm Hg, 10 mm Hg, 5 mm Hg, and 3 mm Hg. After pumping down to each level, the pump is valved off and the cavity pressure monitored. The cavity pressure will rise as water and other volatiles in the cavity evaporate. When the cavity pressure stabilizes, the pump is valved in to complete the vacuum drying process. It may be necessary to repeat some steps, depending on the rate and extent of the pressure increase. The cavity pressure shall be maintained above 0.75 mm Hg. Vacuum drying is complete when the pressure stabilizes for a minimum of 30 minutes at 3 mm Hg or less, as specified in Section 3.1.1 of the Technical Specifications [9-5].
Note: The user shall ensure that the vacuum pump is isolated from the DSC cavity when demonstrating compliance with Section 3.1.1 of the Technical Specification [9-5] requirements. Simply closing the valve between the DSC and the vacuum pump is not sufficient, as a faulty valve allows the vacuum pump to continue to draw a vacuum on the DSC. Turning off the pump, or opening the suction side of the pump to atmosphere are examples of ways to assure that the pump is not continuing to draw a vacuum on the DSC.
CAUTION: Radiation dose rates are expected to be high at the port locations. Use proper ALARA practices (e.g., use of temporary shielding, appropriate positioning of personnel, etc.) to minimize personnel exposure.
CAUTION: The addition of Helium into the DSC cavity will increase the temperature of water in the TC/DSC annulus.
All Indicated Changes are in Support of Enclosure 3
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 December 2022 Revision 11 72-1042 Amendment 3 Page 9-11
- 18. Open the valve and allow the helium to flow into the DSC cavity. Until the cavity pressure is greater than 20 mm of Hg, it should be increased in steps of approximately 5 to 10 mm of Hg to ensure the TC/DSC annulus water level is maintained.
- 19. Pressurize the DSC with helium to more than 18 psig, but do not exceed 23 psig and hold for 10 minutes. This pressure test may instead be performed after the second evacuation performed in Step 24.
Note: This is the ASME Code NB-6300 pressure test required per Section 4.4.4 of the Technical Specifications [9-5]. As provided in the Code alternative to NB-6324, the examination for leakage associated with the pressure test is performed via helium leak test method in Step 4 of Section 9.1.4.
- 20. NOT USED.
- 21. NOT USED.
- 22. Depressurize the DSC cavity by releasing the helium through the VDS to the plants spent fuel pool or radioactive waste system.
- 23. Seal weld the prefabricated plug over the vent port and perform root and final dye penetrant weld examinations in accordance with Section 4.4.4 of the Technical Specifications [9-5].
- 24. Re-evacuate the DSC cavity using the VDS. The cavity pressure should be reduced to between 3 and 0.75 mm Hg.
CAUTION: The addition of Helium into the DSC cavity will increase the temperature of water in the TC/DSC annulus. Therefore, continuously monitor the TC/DSC annulus for boiling while Helium is added to the DSC and add demineralized water continuously as required. A water flow rate of 0.35 gpm is recommended during the helium backfill. The flow rate may be adjusted as required to ensure the water remains approximately twelve inches below the top edge of the DSC shell. Ensure that a portion of the TC/DSC annulus is open to atmosphere to allow water vapor to escape. In addition, a feed and bleed system with continuous flow of fresh water can also be used to control the boiling of annulus water.
- 25. Open the valve allow helium to flow into the DSC cavity to pressurize the DSC to 2.5 +/- 1 psig and confirm stable for 30 minutes after filling in accordance with Section 3.1.2 of the Technical Specification [9-5] limits. Until the cavity pressure is greater than 20 mm of Hg, it should be increased in steps of approximately 5 to 10 mm of Hg to ensure the TC/DSC annulus water level is maintained.
- 26. Close the valves on the helium source.
- 27. Decontaminate as necessary.
All Indicated Changes are in Support of Enclosure 3
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 December 2022 Revision 11 72-1042 Amendment 3 Page A.2-4 The MX-LC is used to position the TC skid in the proper position to dock the TC to the HSM-MX at the designated compartment (either upper or lower compartment) of the HSM-MX for the purpose of inserting the DSC into the HSM-MX or withdrawing it from the HSM-MX. The TC skid (TS) with the attached TC is transferred from the transfer trailer (TT) or self-propelled modular transporter (SPMT) to the MX-LC, where the lift links are connected to the TC skid and the TC skid is subsequently detached from and lifted off the transfer trailer/SPMT. Operationally, the MX-LC travels along the face of the HSM-MX on rails positioned on the ISFSI apron, lifts the TC skid to the proper height, and docks the TC to the HSM-MX. Refer to Figure A.2-2 for details of the MX-LC component.
The MX-LC is a unique telescopic gantry crane with jacking towers, and not an electric overhead traveling crane, as described in ASME NOG-1 [A.2-7], and as such, there are multiple sections of ASME NOG-1 [A.2-7] that do not apply to the MX-LC.
Those portions of ASME NOG-1 that are not applicable to the design of the MX-LC involve features for a typical gantry crane with a top running wire rope hoist and trolley unit that do not exist on a telescoping gantry crane with self-locking screw mechanisms. Therefore, the MX-LC component parts must be addressed individually, with regards to applicable criteria located within U.S. NRC regulatory guides and nuclear and non-nuclear industry standards, for the purpose of confirming its single-failure-proof handling capability. The following sections outline the integration of the standards and substantiate the safety of the described systems. A detailed ASME NOG-1 compliance assessment of the MX-LC is provided in Reference [A.2-21].
The MX-LC is designed and analyzed to meet the intent of NUREG-0612 [A.2-9],
Control of Heavy Loads at Nuclear Power Plants, To provide adequate measures to minimize the occurrence of the principal causes of load handling accidents and to provide an adequate level of defense-in-depth for handling heavy loads near spent fuel and safe shutdown systems.
Understanding the ISFSI does not have 10 CFR Part 50 safe shut down equipment or a spent fuel pool, it is recognized that the DSCs loaded with fuel must be safely and securely handled, thereby protecting the fuel from damage and protecting the site and surrounding areas from any potential radiological impacts. Even though the potential for a radiological release is very low, the design objective of the MX-LC is to prevent the occurrence of load handling accidents. Therefore, the licensing basis for the MX-LC is to provide a lifting and handling system that is highly reliable, which makes the likelihood of a load drop event extremely small.
All indicated changes on this page are in response to RAI 2
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 December 2022 Revision 11 72-1042 Amendment 3 Page A.2-9 Structural Design In accordance with ASME NOG-1, the MX-LC is classified as a Type I crane, since it is used to handle a critical load. It is designed to retain control of and hold the load during and after a design basis seismic event. The design includes the stress analysis of the structural elements of the MX-LC and their connections, as well as a stability analysis to demonstrate that the MX-LC will not experience significant sliding or tipping under seismic loading.
For these seismic analyses, a pair of wheel chocks is provided for each of the four gantry boxes to restrain the gantry lower boom from sliding under seismic loading.
The wheel chocks are installed when handling the loaded TC/DSC above the applicable lift height restriction of Technical Specification 5.2.1 [A.2-18], and while the DSC is being inserted into or retracted from the HSM-MX. Retention brackets are also provided at each gantry box to prevent the wheels from leaving the rails during a seismic event. Connections between the upper boom and face of the HSM-MX are provided when in the raised configuration for loading the upper compartments, and a connection between the transfer skid and HSM-MX is also provided. The MX-LC upper boom assembly has four telescoping sections which are braced with viscous dampers to accommodate earthquake loads.
Seismic loads imposed on the MX-LC consider ground motions due to a safe shutdown earthquake (SSE) applied in all three orthogonal directions. The ground motions correspond to the enhanced RG 1.60 response spectrum [A.2-13] scaled to a ZPA of 0.3g in both the horizontal and vertical directions. The mass considered during a seismic event is the distributed mass of the MX-LC and the credible critical load. A structural damping value less than 7% can be conservatively applied for the seismic design of the MX-LC in lieu of 7% damping required in Section 4153.8 of NOG-1.
The structural evaluation of the MX-LC during lifting of the loaded transfer cask is performed for the load combinations specified in ASME NOG-1, Subsection 4140.
The credible critical load of 162 tons is combined with the crane deadload and SSE load for the most limiting extreme environmental load combination. Four configurations are considered for the MX-LC, with the upper boom both in the lowered and raised positions, and with the lift link assemblies both in the fully extended and fully retracted positions. The raised position governs the design due to the higher center of gravity for the load relative to the MX-LC structure.
All indicated changes on this page are in response to RAI 2
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 December 2022 Revision 11 72-1042 Amendment 3 Page A.9-3
- 3. Inspect the DSC, and MX-RRT support pads inside HSM-MX compartment.
- 4. For ALARA purposes, reinstall the HSM-MX door.
- 5. Inspect the HSM-MX air inlet and outlets to ensure that they are clear of debris. Inspect the screens on the air inlet and outlets for damage.
CAUTION: The insides of empty compartments have the potential for high dose rates due to adjacent loaded compartments. Proper ALARA practices should be followed for operations inside these compartments and in the areas outside these compartments whenever the MX-RRT operations are being performed.
- 6. Remove the MX-RRT cover plates and shield plugs.
- 7. Insert and install MX-RRT into HSM-MX. Extend the MX-RRT rollers, secure and verify that the rollers are extended.
- 8. Transport the TC from the plant's fuel/reactor building to the ISFSI along the designated transfer route.
- 9. Once at the ISFSI, move the transfer trailer inside the MX-LC at home position between the skid and the MX-LC grappling mechanism.
- 10. Use the MX-LC grappling mechanism to capture the skid along with TC, disengage the skid positioning system, move the skid up in the vertical direction to clear it from the transfer trailer, and then the transfer trailer is moved from MX-LC.
- 11. Remove the FC system, and install the ram cylinder assembly.
11a. If the HSM-MX upper compartment is to be loaded, install the MX-LC brackets to the embedments on each adjacent HSM-MX module.
- 12. Remove the HSM-MX door.
- 13. Unbolt and remove the TC top cover plate.
- 14. Move MX-LC along the rail in front of HSM-MX until the TC is laterally aligned with the targeted compartment.
14a. Prior to lifting the TC above the applicable lift height restriction of TS 5.2.1 [A.9-5],
install the wheel chocks on the MX-LC gantry boxes with a gap of no greater than 1/4.
- 15. The skid is moved until the target compartment is reached. If necessary, adjust the MX-LC position until the MX-LC is properly aligned with the targeted compartment. For alignment with the HSM-MX upper modules, the MX-LC Chocks may be temporarily adjusted by no greater than 1/4" while performing lateral alignment of the TC.
- 16. Secure the MX-LC/skid/cask to the front wall embedments of the HSM-MX using the restraints.
All indicated changes on this page are in response to RAI 1
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 December 2022 Revision 11 72-1042 Amendment 3 Page A.9-4 16a. Install the wheel chocks on the MX-LC gantry boxes, if not previously installed.
- 17. The hydraulic power unit is connected to the ram cylinder. The grapple is moved until it engages with grapple ring of the canister. Using the ram cylinder, fully insert the DSC into the HSM-MX compartment.
- 18. Disengage the ram grapple mechanism so that the grapple is retracted away from the DSC grapple ring.
Note: The time limit for transfer operations, if any, starts with the initiation of the TC/DSC annulus water draining described in Step 9 of Section 9.1.4 and ends when the DSC is fully seated onto the front and rear DSC supports.
CAUTION: Verify that the applicable time limits for transfer operations of Section 3.1.3 of the Technical Specifications [A.9-5] are met.
- 20. Remove the wall embedments from the HSM-MX.
20a. Remove the wheel chocks from the MX-LC gantry boxes.
- 22. Place the HSM-MX door. Verify that the HSM dose rates are compliant with the limits specified in Section 5.1.2 of the Technical Specifications [A.9-5].
- 23. Move MX-LC to its home position, and the transfer trailer is moved into accepting position.
- 24. Lower the Skid along with TC onto the transfer trailer. Reconnect the skid positioning system. Remove the ram cylinder assembly.
- 25. Bolt the TC cover plate into place, tightening the bolts to the required torque in a star pattern.
CAUTION: The insides of loaded compartments have the potential for high dose rates.
Proper ALARA practices should be followed for operations in the areas outside these compartments whenever the MX-RRT operations are being performed.
- 26. Remove the MX-RRT from the HSM-MX.
- 27. Place MX-RRT shield plugs and cover plates for the MX-RRT accesses.
27a. If previously installed, remove the MX-LC brackets from the HSM-MXs.
All indicated changes on this page are in response to RAI 1
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 December 2022 Revision 11 72-1042 Amendment 3 Page A.9-7
- 6. Remove the MX-RRT shield blocks plugs and cover plates.
- 7. Insert and install MX-RRT into HSM-MX. Extend the MX-RRT rollers, secure and verify that the rollers are extended.
CAUTION: High dose rates are expected in the HSM-MX compartment after removal of the HSM-MX door. Proper ALARA practices should be followed.
7a.
If the HSM-MX upper compartment is to be unloaded, install the MX-LC brackets to the embedments on each adjacent HSM-MX module.
- 8. Remove the HSM-MX door.
- 9. Unbolt and remove the TC top cover plate.
- 10. Move MX-LC along the rail in front of HSM-MX until the TC is laterally aligned with the targeted compartment.
- 11. Not Used.
- 12. The skid is moved until the target compartment is reached. If necessary, adjust the MX-LC position until the MX-LC is properly aligned with the targeted compartment.
- 13. Secure the MX-LC/skid/cask to the front wall embedments of the HSM-MX using the restraints.
13a. Install the wheel chocks on the MX-LC gantry boxes.
- 14. The hydraulic power unit is connected to the ram cylinder. Remove the bottom ram access cover plate. Extend the ram through the TC into the HSM-MX until it engages with the grapple ring of the canister.
- 15. Operate the ram grapple and engage the grapple arms with the DSC grapple ring.
- 16. Recheck all alignment marks and ready all systems for DSC transfer.
CAUTION: The time limits for the unloading of the DSC should be determined using the heat loads at the time of the unloading operation and the methodology presented in Sections 4.5 and 4.6 before pulling the DSC out of the HSM-MX.
- 18. Disengage the ram grapple mechanism so that the grapple is retracted away from the DSC grapple ring.
- 19. Retract and disengage the ram system from the TC and move it clear of the TC. Remove the TC embedments from the HSM-MX.
All indicated changes on this page are in response to RAI 1
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 December 2022 Revision 11 72-1042 Amendment 3 Page A.9-8
20a. Remove the wheel chocks from the MX-LC gantry boxes.
- 21. Move MX-LC to its home position, and move the transfer trailer to accepting position.
- 22. Lower the skid along with TC onto the transfer trailer. Reconnect the skid positioning system, remove the ram cylinder assembly, and install the air circulation system if a time limit to complete transfer operations applies.
- 23. Bolt the TC cover plate into place, tightening the bolts to the required torque in a star pattern.
CAUTION: The insides of empty compartments have the potential for high dose rates due to adjacent loaded compartments. Proper ALARA practices should be followed for operations inside these compartments and in the areas outside these compartments whenever the MX-RRT operations are being performed.
- 24. Disconnect MX-RRT operating mechanism and retract MX-RRT to MX-RRT handling device.
- 25. Place MX-RRT shield plugs and cover plates for the MX-RRT accesses.
- 26. Move the transfer trailer from MX-LC and ready the trailer for transfer.
- 27. Replace the HSM-MX door.
27a. If previously installed, remove the MX-LC brackets from the HSM-MXs.
A.9.2.2 Removal of Fuel from the DSC No change, see Section 9.2.2.
All indicated changes on this page are in response to RAI 1 to E-61866 CoC 1042 UFSAR Revision 4 Chapter 9 Pages
NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 Page 9-10
- 16. Connect a hose from the discharge side of the VDS to the plant's radioactive waste system or spent fuel pool.
Note: Proceed cautiously when evacuating the DSC to avoid freezing consequences.
- 17. Open the valve on the suction side of the pump, start the VDS and draw a vacuum on the DSC cavity. The cavity pressure should be reduced in steps of approximately 100 mm Hg, 50 mm Hg, 25 mm Hg, 15 mm Hg, 10 mm Hg, 5 mm Hg, and 3 mm Hg. After pumping down to each level, the pump is valved off and the cavity pressure monitored. The cavity pressure will rise as water and other volatiles in the cavity evaporate. When the cavity pressure stabilizes, the pump is valved in to complete the vacuum drying process. It may be necessary to repeat some steps, depending on the rate and extent of the pressure increase. The cavity pressure shall be maintained above 0.75 mm Hg. Vacuum drying is complete when the pressure stabilizes for a minimum of 30 minutes at 3 mm Hg or less, as specified in Section 3.1.1 of the Technical Specifications [9-5].
Note: The user shall ensure that the vacuum pump is isolated from the DSC cavity when demonstrating compliance with Section 3.1.1 of the Technical Specification [9-5] requirements. Simply closing the valve between the DSC and the vacuum pump is not sufficient, as a faulty valve allows the vacuum pump to continue to draw a vacuum on the DSC. Turning off the pump, or opening the suction side of the pump to atmosphere are examples of ways to assure that the pump is not continuing to draw a vacuum on the DSC.
CAUTION: Radiation dose rates are expected to be high at the port locations. Use proper ALARA practices (e.g., use of temporary shielding, appropriate positioning of personnel, etc.) to minimize personnel exposure.
- 19. Pressurize the DSC with helium to more than 18 psig, but do not exceed 23 psig and hold for 10 minutes. This pressure test may instead be performed after the second evacuation performed in Step 24.
Note: This is the ASME Code NB-6300 pressure test required per Section 4.4.4 of the Technical Specifications [9-5]. As provided in the Code alternative to NB-6324, the examination for leakage associated with the pressure test is performed via helium leak test method in Step 4 of Section 9.1.4.
- 20. NOT USED.
- 21. NOT USED.
- 22. Depressurize the DSC cavity by releasing the helium through the VDS to the plants spent fuel pool or radioactive waste system.
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NUHOMS EOS System Updated Final Safety Analysis Report Rev. 4, 06/22 Page 9-11
- 23. Seal weld the prefabricated plug over the vent port and perform root and final dye penetrant weld examinations in accordance with Section 4.4.4 of the Technical Specifications [9-5].
- 24. Re-evacuate the DSC cavity using the VDS. The cavity pressure should be reduced to between 3 and 0.75 mm Hg.
CAUTION: The addition of Helium into the DSC cavity will increase the temperature of water in the TC/DSC annulus. Therefore, continuously monitor the TC/DSC annulus for boiling while Helium is added to the DSC and add water from the top as required. Ensure that a portion of the TC/DSC annulus is open to atmosphere to allow water vapor to escape. In addition, a feed and bleed system with continuous flow of fresh water can also be used to control the boiling of annulus water.
- 25. Open the valve allow helium to flow into the DSC cavity to pressurize the DSC to 2.5 +/- 1 psig and confirm stable for 30 minutes after filling in accordance with Section 3.1.2 of the Technical Specification [9-5] limits.
- 26. Close the valves on the helium source.
- 27. Decontaminate as necessary.
9.1.4 DSC Sealing Operations CAUTION: During the performance of steps listed in Section 9.1.4, monitor the TC/DSC annulus water level and replenish, as necessary, to maintain cooling. Boiling of TC/DSC annulus water is expected at high heat loads. Consider adding water from the top and ensure that a portion of the TC/DSC annulus is open to atmosphere to allow water vapor to escape. In addition, a feed and bleed system with continuous flow of fresh water can also be used to control the boiling of annulus water for high heat load systems.
- 1. Disconnect the VDS from the DSC. Seal weld the prefabricated cover plate over the drain port, inject helium into blind space just prior to completing welding, and perform root and final dye penetrant weld examinations in accordance with Section 4.4.4 of the Technical Specification [9-5] requirements.
- 2. Temporary shielding may be installed as necessary to minimize personnel exposure. Place the outer top cover plate (OTCP) onto the DSC. Verify proper fit up of the OTCP with the DSC shell. Install the welding machine onto the OTCP.
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to E-61866 CoC 1042 Amendment 3, Revision 11 Supporting Information File for RAI 3 Withheld Pursuant to 10 CFR 2.390 The following is the supporting document associated with Enclosure 2, RAI Number 3:
NUH-MX-M-001, Revision 0, Matrix Transfer Equipment Maintenance Manual