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Enclosure 8: CoC 1042 Amendment 2, Revision 5 UFSAR Changed Pages
	ML20190A142
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Site:	07201042
Issue date:	06/30/2020
From:	; TN Americas LLC
To:	; Office of Nuclear Material Safety and Safeguards
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Enclosure 8 to E-56684 CoC 1042 Amendment 2, Revision 5 UFSAR Changed Pages (Public Version)

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 1-2 Amendment 2 of this UFSAR incorporates the 61BTH Type 2 dry storage canister (DSC) for storage in the new NUHOMS MATRIX (HSM-MX) design submitted under Amendment 1 to CoC 1042. The 61BTH Type 2 DSC is from CoC No. 1004 Amendment No. 15. The design will allow for intact, damaged, and failed fuel within the 61BTH Type 2 DSC, the definitions of which come from CoC No. 1042 Amendment No. 1. The EOS-89BTH DSC is limited to intact BWR fuel only. The design changes to the HSM-MX include front and rear DSC support spacer blocks, and a rear spacer block to maintain the centerline of the DSC.

Comprehensive analyses of components to the NUH61BTH Type 2 DSC and the OS197 TC as used in the HSM-MX are provided in Appendix B.

Additionally, Amendment 2 adds two new heat load zone configurations (HLZCs) for the EOS-37PTH for higher heat load assemblies, up to 3.5 kW/assembly, to allow for damaged and failed fuel storage. Amendment 2 also adds HLZCs (Type 1, Type 4L, and Type 5) that were introduced in CoC No.1042 Amendment No. 1 to the EOS-37PTH Type 4H basket. For the EOS-TC108, Amendment 2 adds HLZCs 4 through 9 for the 4H basket and reduces the minimum cooling time to 2 years (HLZCs 2 through 9).

All Indicated Changes are in response to RAI SH-RAI-1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 1-8 1.2.1 NUHOMS EOS System Characteristics EOS-37PTH DSC 1.2.1.1 The key design parameters of the EOS-37PTH DSC are listed in Table 1-1. The primary confinement boundary for the EOS-37PTH DSC consists of the cylindrical shell, the top and bottom inner cover plates, the siphon/drain port cover plate, vent plug, and the associated welds. Note that the terms drain port and siphon are used interchangeably throughout the UFSAR and TS. The outer top cover plate and the test port plug provide the redundant sealing required by 10 CFR 72.236(e). The top and bottom shield plugs provide shielding for the EOS-37PTH DSC so that occupational doses at the ends are minimized during drying, sealing, handling, and transfer operations. To provide additional operational flexibility, the top shield plug may be integrated with the inner top cover plate. When used without distinction, the terms inner top cover plate or shield plug will also include the shield plug integrated inner top cover plate.

The cylindrical shell and inner bottom cover plate confinement boundary welds are fully compliant with Subsection NB of the ASME Code and are made during fabrication. The confinement boundary weld between the shell and the inner top cover (including drain port cover plate and vent plug welds), and the structural attachment weld between the shell and the outer top cover plate (including the test port weld) are in accordance with Alternatives to the ASME code as described in Section 4.4.4 of the Technical Specifications [1-7].

Both drain port cover plate and vent plug welds are made after drying operations are completed. There are no credible accidents that could breach the confinement boundary of the EOS-37PTH DSC, as documented in Chapters 3 and 12.

The EOS-37PTH DSC basket structure, shown schematically in Figure 1-2, consists of interlocking slotted plates to form an egg-crate type structure. The egg-crate structure forms a grid of 37 fuel compartments that house the PWR SFAs. The egg-crate grid structure is composed of one or more of the following: a steel plate, an aluminum plate and a neutron absorber plate. The steel plates are fabricated from high-strength low-alloy (HSLA) steels such as ASTM A829 Gr 4130 (AISI 4130) steel, hot rolled, heat-treated and tempered to provide structural support for the FAs. The poison plates are made of borated metal matrix composites (MMCs) and provide the necessary criticality control. The aluminum plates, together with the poison plates, provide a heat conduction path from the FAs to the DSC rails and shell.

The aluminum plates of the EOS-37PTH DSC may be offset vertically from the steel and poison plates. This configuration is termed the EOS-37PTH damaged/failed fuel basket. This configuration is used in conjunction with top and bottom end caps to allow for the storage of damaged FAs, as shown in Drawing EOS01-1010-SAR.

All Indicated Changes are in response to Enclosure 12, Item 3

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 1-10 EOS-89BTH DSC 1.2.1.2 The key design parameters of the EOS-89BTH DSC are listed in Table 1-1. The primary confinement boundary for the EOS-89BTH DSC consists of the cylindrical shell, the top and bottom inner cover plates, the drain port cover plate, vent plug, and the associated welds. The outer top and bottom cover plates, test port plug and associated welds form the redundant confinement boundary. The top and bottom shield plugs provide shielding for the EOS-89BTH DSC to minimize occupational doses at the ends during drying, sealing, handling, and transfer operations. To provide additional operational flexibility, the top shield plug may be integrated with the inner top cover plate. When used without distinction, the terms inner top cover plate or shield plug will also include the shield plug integrated inner top cover plate.

The cylindrical shell and inner bottom cover plate confinement boundary welds are fully compliant with Subsection NB of the ASME Code and are made during fabrication. The confinement boundary weld between the shell and the inner top cover (including drain port cover plate and vent plug welds), and structural attachment weld between the shell and the outer top cover plate (including the test plug weld) are in accordance with Alternatives to the ASME code as described in Section 4.4.4 of the Technical Specifications [1-7].

Both drain port cover plate and vent plug welds are made after drying operations are complete. There are no credible accidents that could breach the confinement boundary of the EOS-89BTH DSC as documented in Chapters 3 and 12.

The EOS-89BTH DSC basket structure, shown schematically in Figure 1-4, consists of interlocking slotted plates to form an egg-crate-type structure. The egg-crate structure forms a grid of 89 fuel compartments that house the BWR SFAs. The egg-crate grid structure is composed of one or more of the following: a steel plate, an aluminum plate, and a neutron absorber plate. The steel plates are fabricated from HSLA steels such as ASTM A829 Gr 4130 (AISI 4130) steel, hot rolled, heat-treated and tempered to provide structural support for the FAs. The poison plates are made of borated MMCs or BORAL and provide the necessary criticality control. The aluminum plates, together with the poison plates, provide a heat conduction path from the FAs to the DSC rails and shell.

Basket transition rails provide the transition between the rectangular basket structure and the cylindrical DSC shell. The transition rails are made of extruded aluminum open or solid sections, which are reinforced with internal steel as necessary. These transition rails provide the transition to a cylindrical exterior surface to match the inside surface of the DSC shell. The transition rails support the fuel basket egg-crate structure and transfer mechanical loads to the DSC shell. They also provide the thermal conduction path from the basket assembly to the DSC shell wall, making the basket assembly efficient in rejecting heat from its payload. The nominal dimension of each fuel compartment opening is sized to accommodate the limiting assembly with sufficient clearance around the FA.

All Indicated Changes are in response to Enclosure 12, Item 3

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 2-5 Spent Fuel to Be Stored 2.2 The NUHOMS EOS System is designed to accommodate pressurized water reactor (PWR) (14x14, 15x15, 16x16 and 17x17 array designs) and boiling water reactor (BWR) (7x7, 8x8, 9x9 and 10x10 array designs) fuel types that are available for storage. As described in Chapter 1, there are two DSC designs for the NUHOMS EOS System: the EOS-37PTH DSC for PWR fuel and EOS-89BTH DSC for BWR fuel. The EOS-37PTH DSC is designed to accommodate up to 37 intact PWR FAs with uranium dioxide (UO2) fuel, zirconium-alloy cladding, and with or without control components. The EOS-37PTH DSC is also designed to accommodate up to eight damaged FAs or up to four failed fuel canisters (FFCs), with the balance being intact FAs. The EOS-89BTH DSC is designed to accommodate up to 89 intact BWR FAs with UO2 fuel, zirconium-alloy cladding, and with or without fuel channels.

Specifications for the fuel to be stored in the NUHOMS EOS System are provided in Technical Specifications (TS) Sections 2.1 and 2.2.

The cavity length of the DSC is determined for a specific site to match the FA length used at that site, including control components (CCs), as applicable. Both DSCs store intact, including reconstituted and blended low enriched uranium (BLEU), FAs as specified in Table 2-2, Table 2-3 and Table 2-4. Any FA that has fuel characteristics within the range of Table 2-2, Table 2-3 and Table 2-4 and meets the other limits specified for initial enrichment, burnup and heat loads is acceptable for storage in the NUHOMS EOS System. Equivalent fuels manufactured by other vendors are also acceptable.

Damaged and failed fuel from the FA classes detailed in Table 2-2 and PWR fuels in Table 2-4 are also acceptable for storage in the EOS-37PTH DSC in the appropriate compartments. The potential for fuel reconfiguration for intact, damaged, and failed fuel under normal, off-normal, and accident conditions is summarized in Table 2-4a.

All fuel categorized as failed shall be placed in a failed fuel canister (FFC). Failed fuel may include FAs, fuel rods, segments of fuel rods, fuel pellets, and debris. FFCs are not required for damaged FAs, because damaged FAs maintain their geometry under normal and off-normal conditions.

The failed fuel content of each FFC is limited to the maximum metric tons of uranium (MTU) of an intact fuel assembly for each class. These limits are summarized in Table 2-4b. Failed CCs may also be stored inside an FFC. The maximum Co-60 content for failed CCs is the same as intact CCs.

The maximum allowable assembly average burnup is limited to 62 GWd/MTU and the minimum cooling time is two years. Dummy FAs and reconstituted FAs are also included in the EOS-37PTH DSC and EOS-89BTH DSC payloads. Low enriched or natural uranium fuel rods or unirradiated non-fuel rods are acceptable for storage in an EOS-37PTH DSC and EOS-89BTH DSC as intact FAs.

All Indicated Changes are in response to Enclosure 12, Item 1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 2-7 2.2.1 EOS-37PTH DSC The EOS-37PTH DSC stores up to 37 PWR FAs with up to eight damaged FAs or four FFCs with characteristics as described in Table 2-2 and the PWR FAs listed in Table 2-4. One or more PWR fuel designs are grouped under a PWR class. EOS-37PTH DSC payloads may also contain CCs, such as identified below, with thermal and radiological characteristics as listed in Section 2.1 and Figures 1A through 1K of the Technical Specifications [2-18]:

Burnable Poison Rod Assemblies Burnable poison rod assemblies (BPRAs),

Burnable absorber assemblies (BAAs),

Wet annular burnable absorbers (WABAs),

Vibration suppression inserts (VSIs),

Thimble Plug Assemblies Thimble plug assemblies (TPAs),

Control spiders, Orifice rod assemblies (ORAs),

Control Element Assemblies Control rod assemblies (CRAs),

Rod cluster control assemblies (RCCAs),

Control element assemblies (CEAs),

Axial power shaping rod assemblies (APSRAs),

Peripheral power suppression assemblies (PPSAs),

Flux suppression inserts (FSIs),

Neutron Sources Neutron sources, Neutron source assemblies (NSAs).

All Indicated Changes are in response to Enclosure 12, Item 1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 2-9 Damaged fuel containing control components may be stored in the designated damaged fuel compartments. Similarly, failed control component debris may be stored in the FFCs.

Control components not explicitly listed herein are also authorized within the DSC, as long as they meet the following criteria:

1. External materials are limited to zirconium alloys, nickel alloys, and stainless steels,

2. Radiological limits listed in Section 2.1, Section 5.1.2, and Figures 1A through 1K of the Technical Specifications are not exceeded, and

3. They fit within the weight limits and dimensional limits of the DSC.

Figures 1A through 1K of the Technical Specifications [2-18] define the maximum decay heat, failed/damaged fuel locations, and other parameters for PWR fuel assemblies, with or without CCs, authorized for storage. These tables are used to ensure that the decay heat load of the FA to be stored is less than that as specified in each table, and that the corresponding radiation source term is consistent with the shielding analysis presented in Chapter 6. The maximum weight of a FA plus CC, if applicable, is 1,900 lbs.

The heat loads listed in Figures 1A through 1K of the Technical Specifications [2-18]

are the maximum allowable heat loads for each FA and the maximum allowable heat load per DSC. These heat loads can be reduced to ensure adequate heat removal capability is maintained to accommodate site-specific conditions. Some examples of the site-specific conditions are a higher ambient temperature, different blocked vent duration, a requirement to use a different neutron absorber plate or a requirement for a specific coating on the basket steel plates. Each of these changes could result in a change to the inputs of the thermal evaluation utilized in the UFSAR. To ensure that adequate heat removal is maintained with these modified inputs, the bounding evaluations for storage and transfer operations should be re-evaluated. The maximum fuel cladding temperature based on the modified inputs shall be lower than the maximum fuel cladding temperatures listed in the Chapter 4 and Chapter A.4 for the same bounding evaluations.

As limited by their definition, damaged FAs maintain their geometric configuration for normal and off-normal conditions and are confined to their respective compartments by means of top and bottom end caps. Damaged FAs do not contain missing major sub-components like top and bottom nozzles that impact their ability to maintain their geometric configuration for normal and off-normal conditions during loading.

From the standpoint of NUREG-1536 Revision 1, the damaged FAs for the EOS System are more similar to the undamaged FAs, where their geometry is still in the form of intact bundles. For completeness, failed fuel for the EOS System is more similar to the damaged FAs per NUREG-1536 Revision 1 and will require FFCs.

All Indicated Changes are in response to Enclosure 12, Item 1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 2-20 2.4.3 Thermal The NUHOMS EOS System relies on natural convection through the air space in the EOS-HSM to cool the DSC. This passive convective ventilation system is driven by the pressure difference due to the stack effect (Ps) provided by the height difference between the bottom of the DSC and the EOS-HSM air outlet. This pressure difference is greater than the flow pressure drop (Pf) at the design air inlet and outlet temperatures. The details of the ventilation system design are provided in Chapter 4.

Thermal analysis is based on FAs with decay heat up to 50.0 kW per DSC for the EOS-37PTH and up to 43.6 kW per DSC for the EOS-89BTH. Zoning is used to accommodate high per assembly heat loads. The heat load zoning configurations (HLZCs) for the DSCs are shown in Figures 1A through 1K and Figure 2 of the Technical Specifications [2-18]. As noted in Section 2.1 and 2.2 of Technical Specification [2-18], the maximum allowable heat loads may be reduced based on the methodology presented in Chapter 4 or Chapter A.4 for each FA type allowed in either the EOS-37PTH DSC or the EOS-89BTH DSC. For this evaluation, the thermal properties for the various FA types should be determined based on the methodology presented in Chapter 4, Appendix 4.9.1.

The thermal analyses is performed for the environmental conditions listed in Table 2-9.

Peak clad temperature of the fuel at the beginning of the long-term storage does not exceed 400 °C for normal conditions of storage, and for short-term operations, including DSC drying and backfilling. Fuel cladding temperature shall be maintained below 570 °C (1058 °F) for accident conditions involving fire or off-normal storage conditions.

For onsite transfer in the EOS-TC, air circulation may be used, as a recovery action, to facilitate transfer operations when the heat loads in the EOS-37PTH DSC are above 36.35 kW and 34.4 kW in the EOS-89BTH DSC as described in the Technical Specifications [2-18].

Wind deflectors are installed on the EOS-HSM to eliminate the effect of sustained winds for DSCs with Type 1 or Type 2 baskets as described in Section 5.5 of the Technical Specifications [2-18].

2.4.4 Shielding/Confinement/Radiation Protection As described earlier, the DSC shells are a welded stainless or duplex steel pressure vessel that includes thick shield plugs at both ends to maintain occupational exposures as low as reasonably achievable (ALARA). The top end of the DSC has nominally 10 inches of steel shielding and the bottom eight inches of steel shielding. The confinement boundary is designed, fabricated, and tested to ensure that it is leaktight in accordance with [2-15]. Section 2.4.2.1 provides a summary of the features of the DSCs that ensure confinement of the contents.

All Indicated Changes are in response to Enclosure 12, Item 4

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page 4.9.6-6 Appendix 4.9.6 was added in Amendment 1.

4.9.6.1.3 Evaluation for Intact FAs in HLZC 4, 5 and 6 Thermal evaluation of HLZCs 4, 5 and 6 with intact FAs in the EOS-37PTH DSC is presented in Section 4.9.6.1.3.1 for storage conditions, and in Section 4.9.6.1.4 for transfer conditions.

The maximum heat load per DSC for HLZC 6 is limited to 46.0 kW, which is lower compared to the maximum heat load of 50 kW for HLZC 4. In addition, while only loading intact FAs, the heat loads in each zone of HLZC 6 are bounded by HLZC 4. Therefore, thermal evaluation for HLZC 6 with intact FAs is bounded by HLZC 4.

4.9.6.1.3.1 Storage Evaluation This section evaluates the thermal performance of the EOS-HSM loaded with the EOS-37PTH DSC for HLZCs 4, 5 and 6 with intact FAs during normal, off-normal and accident conditions.

4.9.6.1.3.2 Description of Load Cases

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Proprietary All Indicated Changes are in response to RAI 4-5

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page 4.9.6-10 Appendix 4.9.6 was added in Amendment 1.

4.9.6.1.4.1 Description of Load Cases

[

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4.9.6.1.4.2 Ambient Operating Conditions All ambient operating conditions are identical to those described in Section 4.5.

All Indicated Changes are in response to RAI 4-5

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page 4.9.6-23 Appendix 4.9.6 was added in Amendment 1.

A similar behavior will be observed for accident conditions wherein the temperatures determined in Table 4.9.6-6 for HLZC 4 in EOS-TC125 will bound the temperatures during transfer operations in EOS-TC108, except for the gamma shield and neutron shield. As seen from Table 4.9.6-6, the maximum gamma shield temperature is 580 °F with 40 °F to the temperature limit of 620 °F, and a small increase similar to normal condition will not impact the thermal performance. For accident conditions, the neutron shield is considered to be lost and, therefore, the increase observed in normal conditions will not impact the accident evaluation.

Further, as discussed in Section 4.9.6.3.1, HLZC 4 is the bounding HLZC, and the maximum temperatures will be lower for all other HLZCs.

B. Transfer time limits As the temperatures for EOS-TC108 with HLZC 4 are bounded by EOS-TC125 with HLZC 4 (from Section 4.9.6.1.4) for normal and off-normal conditions, the time limits presented in Table 4.9.6-7 and Table 4.9.6-11 remain applicable for the EOS-TC108 with HLZCs 4 through 6 and HLZCs 7 through 9, respectively.

C. Internal pressure For the bounding normal condition with HLZC 4, the average helium gas temperature within the DSC cavity is 550 K. This temperature is lower compared to the design basis value of 565 K (see Table 4-45 of Section 4.7) used to evaluate the internal pressure. Therefore, there is no impact on the internal pressure. In addition, this value of 550 K is also lower compared to 557 K reported in Section 4.9.6.1.4.4 B for the EOS-TC125 with HLZC 4 during normal conditions of transfer. Therefore, it is concluded that the internal pressures for the EOS-37PTH DSC loaded in the EOS-TC108 remain below those for the EOS-37PTH DSC loaded in the EOS-TC125 during normal, off-normal and accident conditions and satisfy the design criteria limits.

Based on this discussion, all of the temperature criteria, along with the internal pressure criteria, are satisfied for transfer of the EOS-37PTH DSC Basket Assembly Type 4H with HLZCs 4 through 9 in EOS-TC108.

All Indicated Changes are in response to RAI 4-6

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page 4.9.7-8 Appendix 4.9.7 is newly added in Amendment 2.

4.9.7.2.2.3 CFD Modeling 4.9.7.2.2.4 Results and Conclusions A. Transfer Time Limits Based on the discussion in Section 4.5.4, the time limit to complete normal and off-normal transfer operations of an EOS-37PTH DSC loaded per HLZC 1 is 10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months . If transfer operations cannot be completed within the time limit, an additional duration of 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months is available to complete one of the recovery actions as described in Section 4.5.4.

All Indicated Changes are in response to RAI 4-2

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 6-2 6.1 Discussions and Results The following is a summary of the methodology and results of the shielding analysis of the EOS system. More detailed information is presented in the body of the chapter.

The EOS-37PTH DSC stores up to 37 PWR FAs, while the EOS-89BTH stores up to 89 BWR FAs. Each EOS-DSC is configured into heat load zones in order to optimize the system performance for both thermal and shielding considerations. Eleven heat load zoning configurations (HLZCs) are available for the EOS-37PTH DSC, and three HLZCs are available for the EOS-89BTH DSC. The HLZCs are defined in the Technical Specifications (TS), Figure 1A through Figure 2 [6-11]. Fuel to be stored is limited by the decay heat and minimum cooling times defined in the Technical Specifications.

The EOS-37PTH DSC is authorized to store up to eight damaged FAs or four FFCs using HLZC 6 or HLZC 8. The EOS-37PTH DSC is also authorized to store up to six damaged FAs or two FFCs using HLZC 10 or 11. Damaged and failed fuel shall not be present in the same DSC.

Source Terms The ORIGEN-ARP module of the Oak Ridge National Laboratory (ORNL)

SCALE6.0 code package [6-1] is used to develop reasonably bounding gamma and neutron source terms. [

]

Control components (CCs) are allowed to be stored within a PWR FA. Examples of CCs include burnable poison rod assemblies (BPRAs) and thimble plug assemblies.

Control components typically have a Co-60 source because of its light element activation, which contributes substantially to transfer cask dose rates. The CC source term used in the analysis is provided in Table 6-37.

BWR fuel does not include CCs other than the fuel channel, which is conservatively included in the source term. The BWR fuel channel is fabricated from zirconium alloy and does not require a Co-60 limit because the contribution to the source term from the fuel channel is negligible.

All Indicated Changes are in response to Enclosure 12, Item 1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 6-15 The only analysis that uses the wet neutron source term is the loading/decontamination stage of the EOS-TCs. After loading/decontamination the EOS-TCs are modeled as dry. No wet neutron sources are provided in the EOS-HSM source term tables because the DSC is always dry when inside the EOS-HSM.

6.2.4 Control Components Control components may also be included with the PWR FAs. For BWR fuel, the fuel channel and associated attachment hardware is included in the BWR source presented in Section 6.2.2, so it will not be discussed in this section. While CCs do not contain fuel, these items result in a source term, primarily due to activation of the Co-59 impurity in the metal. Allowed CCs are identified in Section 2.1 of the TS [6-11].

Any other CC type is acceptable if acceptable dose rates are demonstrated per TS Section 5.1.2 [6-11]. Also, the total as-loaded decay heat of the system, including CCs, must be less that the heat load zoning configurations defined in the TS [6-11].

Control components may be grouped into two categories: (1) those that extend into the top, plenum and active fuel regions of the fuel assembly, and (2) those that essentially extend only into the top and plenum regions of the FA. The BPRA is used as a representative CC for category (1) and the TPA is used as a representative CC for category (2). The objective is to use these representative CC types to develop Co-60 activity limits for CCs.

The BPRAs are assumed to be burned in two cycles to a total host FA burnup of 50 GWd/MTU. This represents a limiting burnup because the absorber material is completely depleted for this burnup. TPAs do not contain burnable poisons and may be used in multiple host FAs for very long burnups. A cumulative host FA burnup of 300 GWd/MTU is assumed. However, a TPA is primarily located in the top nozzle and plenum region of the core where the flux is depressed and the effective burnup of a TPA is significantly less.

A neutron source may be included in CCs, such as an NSA. Typically, the neutron source from an NSA is negligible compared to the neutron source from spent fuel.

However, some neutron sources could have comparable source strength relative to the FAs. For this purpose, the loading of neutron sources is limited to the interior locations of the EOS-37PTH basket to maximize self shielding. The inner locations are defined in Figure 6-1.

Representative BPRA hardware masses are available for three BPRA types:

B&W 15x15 WE 17x17 Pyrex WE 17x17 WABA The BPRA hardware masses are provided in Table 6-32.

All Indicated Changes are in response to Enclosure 12, Item 1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 6-17 For the TPA plenum, the effective burnup is 300*0.2 = 60 GWd/MTU, while for the TPA top the effective burnup is 300*0.1 = 30 GWd/MTU. This reduces the cumulative burnup in each region to a value within the bounds of a typical ORIGEN-ARP model.

The TPA irradiation time is input to match the true irradiation time to properly credit Co-60 decay during the irradiation. Assuming a reactor assembly power of 19.68 MW and fuel loading of 0.492 MTU, the irradiation time to achieve a cumulative fuel assembly burnup of 300,000 GWd/MTU is 7,500 days. Because the irradiation time is fixed at 7,500 days, the FA power is selected to give the desired effective burnup in the plenum and top regions. For the top, the assembly power is 1.968 MW to achieve an effective burnup of 30 GWd/MTU. For the plenum, the assembly power is 3.936 MW to achieve an effective burnup of 60 GWd/MTU.

For simplicity of input preparation in the TPA calculation, no credit is taken for down time between cycles (typically assumed to be 30 days). Using approximately 12 cycles to achieve a burnup of 300 GWd/MTU, the conservatism of this assumption is 11*30 = 330 days of uncredited decay time.

Results for Co-60 activity and decay heat for both the BPRA and TPA are summarized in Table 6-36 for a cooling time of 2 years. It is observed that the BPRA source may be used in the active fuel region, as the TPA does not extend into this region.

However, the TPA has a larger source than the BPRA in the plenum and top regions due to the high TPA burnup. Decay heat for both is small compared to SFA but must be accounted for during loading. The CC source used in the detailed PWR dose rate calculations is a hybrid CC source that combines the active fuel source of the BPRA with the top/plenum source of the TPA. This source is provided in Table 6-37. The CC source significantly impacts the peak dose rates on the side of the EOS-TC, due to the reduced lead thickness near the top nozzle.

The CC source used in the analysis is conservative due to the high burnups, short cooling time, and the hybrid approach. The same high-activity CC source is used in every basket location in all EOS-37PTH DSC shielding analyses. For these reasons, the total as-modeled CC source per DSC will generally bound as-loaded CCs by a large margin. The total as-modeled CC source per DSC is summarized in Table 6-37a. Individual CCs may exceed the design basis CC source defined in Table 6-37 as long as the per-DSC Co-60 equivalent limits provided in Table 6-37a are met and/or acceptable dose rates are demonstrated. The site-specific dose rate analyses performed under 10 CFR 72.212 should include CCs, if present.

Because the vent dose rates have a significant Cs-137 contribution from fission products, the CC contribution to dose rates becomes significantly less important when the EOS-37PTH DSC is in the storage configuration compared to the transfer configuration. A sensitivity study performed for the HSM-MX indicates that the CC source provided in Table 6-37 contributes approximately 4% of the average front dose rate, which is within the uncertainty of the methodology. The CC contribution for the EOS-HSM would be similar.

All Indicated Changes are in response to Enclosure 12, Item 2

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 6-18 Table 6-37a is expressed in terms of Co-60 equivalent because some CC designs feature dose rate producing isotopes in addition to Co-60 (e.g., control rods containing silver or hafnium). For these CC types, it is convenient to convert the active fuel region CC sources to the equivalent activity of Co-60 that results in the same dose rate. This approach provides a common baseline for comparison against Table 6-37a. For the top/plenum regions, Co-60 equivalent is simply the Co-60 activity because the top/plenum regions are always dominated by Co-60. Also, for CCs that contain primarily Co-60 in the active region (e.g., BPRAs), the Co-60 equivalent is simply the Co-60 activity.

The Co-60 equivalence methodology is generally applicable only for control rods containing silver or hafnium. The fuel assembly source terms developed in Section 6.2.2 are selected using simplified MCNP models (i.e., response functions) to estimate the dose rate on the side of the transfer cask or EOS-HSM roof vent. The same methodology may be used to estimate Co-60 equivalence. The Co-60 equivalent activity is then SDBS*(DCC/DDBS), where SDBS is the Co-60 activity of the design basis source (882.6 Ci, from Table 6-37), DCC is the response function dose rate for an arbitrary CC source, and DDBS is the response function dose rate corresponding to the design basis CC source.

6.2.5 Blended Low Enriched Uranium Fuel All Indicated Changes are in response to Enclosure 12, Item 2

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 6-107 Table 6-37a Co-60 Equivalent Activity for CCs Stored in the EOS-37PTH DSC Fuel Region Maximum Co-60 Equivalent Activity per DSC (Curies/DSC)(1)

Active Fuel 32,656 Plenum/Top Region 6,671 Notes:

1. NSAs and Neutron Sources shall only be stored in the inner zone of the basket. Figure 6-1 defines the compartments categorized as the Inner and Peripheral Zones.

All Indicated Changes are in response to Enclosure 12, Items 1 and 2

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 12-8 Corrective Actions The DSC should be inspected for damage, which would include an evaluation of the accident specifics such as the decay heat load, the ambient temperature, the time from loss of cooling or neutron shield water to the time the cooling or water are re-introduced, etc. The transfer cask and DSC would be moved only after these evaluations determined it was safe to do so.

The DSC is then opened and the fuel removed for inspection, as necessary. Removal of the EOS-TC top cover plate may require cutting of the bolts in the event of a corner drop onto the top end. These operations take place in the plant fuel building decontamination area and spent fuel pool after recovery of the EOS-TC.

Following recovery of the EOS-TC and unloading of the DSC, the EOS-TC is inspected, repaired and tested as appropriate prior to reuse.

For recovery of the EOS-TC and contents, it may be necessary to develop a special sling/lifting apparatus to move the EOS-TC from the drop site to the fuel pool. This may require several weeks of planning to ensure all steps are correctly organized.

During this time, lead blankets may be added to the EOS-TC to minimize onsite exposure to site operations personnel. The EOS-TC can be roped off to ensure the safety of the site personnel.

12.3.2 Earthquake Cause of Accident The explicitly evaluated seismic response spectra for the NUHOMS EOS System consist of the U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide 1.60 (Reg. Guide 1.60) [12-6] response spectra, anchored to a maximum ground acceleration of 0.45g horizontal and 0.30g for the vertical peak accelerations. The results of the frequency analysis of the EOS-HSM structure (which includes a simplified model of the DSC) yield a lowest frequency of 18.7 Hz in the transverse direction and 32.7 Hz in the longitudinal direction. The lowest vertical frequency is 60.3 Hz. Thus, based on the Reg. Guide 1.60 response spectra amplifications, and conservatively using ZPA values of 0.50g horizontal and 0.333g vertical, the corresponding seismic accelerations used for the structural design of the EOS-HSM are 0.936g and 0.628g in the transverse and longitudinal directions, respectively, and 0.333g in the vertical direction. The corresponding accelerations applicable to the DSC are 1.229g and 0.694g in the transverse and longitudinal directions, respectively, and 0.333g in the vertical direction. Stability analyses are based on accelerations of 0.45g horizontal and 0.30g vertical.

Accident Analysis The seismic analyses of the components that are important to safety are analyzed as follows:

All Indicated Changes are in response to RAI 8-4

NUHOMS EOS System Updated Final Safety Analysis Report Rev. 2, 01/20 June 2020 Revision 5 72-1042 Amendment 2 Page 12-12 Corrective Action After excessive high winds or a tornado, the EOS-TC is inspected for damage. These operations take place in the plant fuel building decontamination area and spent fuel pool after recovery of the EOS-TC. If the air circulation on the EOS-TC was lost, and time limits for transfer exceeded, the DSC should be inspected for damage, which would include an evaluation of the accident specifics such as the decay heat load, the ambient temperature, the time from loss of cooling or neutron shield water to the time the cooling or water are re-introduced, etc. The transfer cask and DSC would be moved only after these evaluations determined it was safe to do so. Following recovery of the EOS-TC and unloading of the DSC, the EOS-TC is inspected, repaired and tested as appropriate prior to reuse.

For recovery of the EOS-TC and contents, it may be necessary to develop a special sling/lifting apparatus to move the EOS-TC from the site to the fuel pool. This may require several weeks of planning to ensure all steps are correctly organized. During this time, lead blankets may be added to the EOS-TC to minimize on-site exposure to site operations personnel. The EOS-TC can be roped-off to ensure the safety of the site personnel.

12.3.5 Flood Cause of Accident Flooding conditions simulating a range of flood types, such as tsunami and seiches as specified in 10 CFR 72.122 (b) are considered. In addition, floods resulting from other sources, such as high water from a river or a broken dam, are postulated as the cause of the accident.

Accident Analysis The HSM is evaluated for flooding in Appendix 3.9.4. Based on the evaluation presented in that section, the HSM can withstand the design basis flood.

Accident Dose Calculation The radiation dose due to flooding of the HSM is negligible. Flooding does not breach the DSC confinement boundary. Therefore, radioactive material inside the DSC remains sealed in the DSC and, therefore, does not contaminate the encroaching flood water.

Corrective Actions Because of the location and geometry of the HSM vents, it is unlikely that any significant amount of silt would enter an HSM should flooding occur. Any silt deposits are removed using a pump suction hose or fire hose inserted through the inlet vent to suck the silt out, or to produce a high velocity water flow to flush the silt through the HSM inlet vents.

All Indicated Changes are in response to RAI 8-4

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.3-4 Appendix B is newly added in Amendment 2.

B.3.3 Mechanical Properties of Materials B.3.3.1 61BTH Type 2 DSC No change to Section T.3.3 of the CoC 1004 UFSAR [B.33].

B.3.3.2 OS197 TC The material properties for OS197TC are summarized in Section B.8.2.2.

B.3.3.3 HSM-MX The material properties for the HSM-MX are summarized in Chapter A.8.

All Indicated Changes are in response to RAI 8-2

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.4-21 Appendix B is newly added in Amendment 2.

B.4.5 Thermal Evaluation for Transfer Casks with 61BTH Type 2 DSC The OS197 TCs (OS197H, OS197FC, and OS197FC-B) are used to transfer the loaded 61BTH Type 2 DSC between the fuel building and the ISFSI. Thermal evaluation of the 61BTH Type 2 DSCs in the OS197 TCs is presented in Appendix T, Chapter T.4 of [B.42]. No changes are considered to these thermal evaluations for transfer operations due to the following reasons:

1. 61BTH Type 2 DSC and OS197 TC are identical to the design previously evaluated in Appendix T of CoC 1004 [B.42] as discussed in Chapter B.1, Section B.1.1.

2. The combination of DSC/TC for transfer operations remains unchanged from those evaluated in Appendix T, Chapter T.4 of [B.42].

3. HLZCs considered for the 61BTH Type 2 DSC including the placement of damaged/failed fuel assemblies are identical to those previously evaluated in Appendix T, Chapter T.4 of [B.42].

4. Ambient conditions for transfer operations presented in Section B.4.3 for transfer operations remain identical to the ambient conditions considered in Appendix T, Section T.4.5.2 of [B.42].

5. Various load cases evaluated for transfer operations in Appendix T, Section T.4.5.2 of [B.42] remain applicable without any changes.

6. Time limits for transfer operations if necessary are determined based on those evaluated in Appendix T, Section T.4.5.4 of [B.42].

Background of Transfer Evaluation in CoC 1004 Thermal evaluation for transfer operations for the 61BTH Type 2 DSCs in the OS197 TCs in Appendix T, Chapter T.4 of [B.42] are performed using a two-step approach.

The two steps are:

1. Thermal evaluation of the OS197TCs with the 61BTH DSC is performed to determine the DSC shell temperature profile and the maximum component temperatures of the OS197 TC components.

In this step, the fuel basket and the hold down ring within the 61BTH Type 2 DSC are modeled as homogenous solids. Since the fuel basket is modeled as homogenous solids, this step only considers the total heat load per DSC and does not depend on the individual HLZCs. Based on a review of the various HLZCs, two sets of evaluations are performed. The first set is for transfer operations with heat loads 22.0 kW and the second set is for transfer operations with heat loads

> 22.0 kW and 31.2 kW.

This evaluation is summarized in Section B.4.5.1.

2. Thermal evaluation of the 61BTH Type 2 DSC to determine the maximum fuel cladding temperature and basket component temperatures for intact, damaged and failed fuel.

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In this step, a detailed model of the 61BTH Type 2 DSC including the fuel basket is developed and temperatures profiles for the DSC shell from Step 1 are retrieved and applied as boundary condition. Since each individual fuel assembly is modeled, this step evaluates the performance of various HLZCs considered and determines the maximum fuel cladding temperature and other DSC component temperatures.

This evaluation is summarized in Section B.4.5.2.

B.4.5.1 Thermal Evaluation of OS197 TCs with 61BTH DSC Based on the discussion in Appendix T, Section T.4.5 of [B.42], OS197 and OS197H TCs are only allowed to transfer a 61BTH Type 2 DSC when the heat load is less than or equal to 22.0 kW and OS197FC-B TC with air circulation is used if the heat load is greater than 22.0 kW and less than or equal to 31.2 kW.

The 61BTH Type 2 DSC loaded in the OS197 TC is evaluated for following decay heat loads:

1. The OS197FC-B TCs are designed and analyzed for transferring 61BTH Type 2 DSCs with a maximum decay heat load of 31.2 kW (HLZC 5 through HLZC 8 and HLZC 10 of Appendix T.4 of [B.42]),

2. The OS197/OS197H TCs are designed and analyzed for transferring 61BTH DSCs with a maximum decay heat load of 22.0 kW (HLZC 1 through HLZC 4 and HLZC 9 of Appendix T.4 of [B.42]).

This section also establishes the maximum time limits for transfer operations during normal and off-normal conditions, and recommends the applicable corrective actions if the transfer operations cannot be completed within the time limits. The time limits are necessary to satisfy the criteria described in Section B.4.2 for the fuel cladding and for the various components of the TCs. There are no time limits for any postulated accident conditions considered during transfer operations.

The OS197FC-B TC contains design provisions for the use of air circulation system to improve its thermal performance for heat loads greater than 22.0 kW for 61BTH Type 2 DSC. The air circulation system consists of redundant, industrial grade pressure blowers and power systems, ducting, etc. When operating, the fan system is expected to generate a flow rate of 400 cfm or greater, which will be ducted to the location of the ram access cover at the bottom of the TC. The air circulation system is not needed for heat loads 22.0 kW. Section B.4.5.6 establishes the minimum duration required to operate the air circulation. It also evaluates the duration available once the air circulation is turned off to transfer the DSC to the storage module. This evaluation is based on 61BTH Type 2 DSC with maximum allowable heat load of 31.2 kW. If the maximum heat load of a DSC is less than 31.2 kW, new time limits may be determined to provide additional time for these transfer operations.

All Indicated Changes are in response to RAI 4-7

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.4-25 Appendix B is newly added in Amendment 2.

The results from Section B.4.5.2 documented in Tables T.4-12 and T.4-17 of [B.42]

show that, even with these shell temperatures for normal and off-normal transfer conditions, there is considerable margin in the bounding cladding temperatures (734 ºF and 722 ºF calculated for normal and off-normal cases, respectively, vs. a 752 ºF limit).

B.4.5.1.3.2 Normal and Off-Normal Transfer with Forced Air Circulation There is no change to the normal and off-normal transfer evaluations described in Appendix T.4, Section T.4.5.3.2 of [B.42] when air circulation is enabled.

For the transfer time periods exceeding the specific time limits above 22.0 kW, one of the corrective actions available to limit the temperature increase is to initiate air circulation in the TC/DSC annulus.

Table T.4-9 of Appendix T.4 of [B.42] presents the maximum component temperatures achieved under bounding normal and off-normal ambient operating conditions for the OS197FC-B TC with a 61BTH DSC with 31.2 kW of decay heat and a flow rate of 400 cfm of air circulation. As seen, all component temperatures are below their limits.

B.4.5.1.3.3 Accident Transfer There is no change to the accident transfer thermal results presented in Appendix T.4, Section T.4.5.3.3 of [B.42].

Based on the discussion in Appendix T.4, Section T.4.5.3.3 of [B.42], loss of neutron shield is the bounding accident condition. Table T.4-10 of [B.42] presents the peak component temperatures achieved under this accident at steady-state conditions.

B.4.5.1.4 Evaluation of OS197FC-B TC Performance There is no change to the evaluation presented in Appendix T, Section T.4.5.4 of

[B.42] on the thermal performance of the OS197FC-B TC for normal, off-normal, and accident conditions of operation when heat loads are less than or equal to 22 kW.

For heat loads > 22kW and 31.2 kW, the transfer time limits of 26 hours3.009259e-4 days 0.00722 hours 4.298942e-5 weeks 9.893e-6 months and 13 hours1.50463e-4 days 0.00361 hours 2.149471e-5 weeks 4.9465e-6 months specified in Appendix T.4.5.4 of [B.42] are based on a 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months recovery time.

However, to be consistent with the EOS-37PTH and EOS-89BTH DSCs the recovery time to complete the various action statements in LCO 3.1.3 of the Technical Specifications [B.43] is increased by 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months to a total of 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months with corresponding reduction in the transfer time limits. Therefore, the time limits for EOS-61BTH DSC are reduced to 23 hours2.662037e-4 days 0.00639 hours 3.80291e-5 weeks 8.7515e-6 months and 10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months based on the HLZC.

All Indicated Changes are in response to RAI 4-7

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.4-26 Appendix B is newly added in Amendment 2.

Based on the discussion in Section 4.5.4, if air circulation cannot be initiated within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months after exceeding the transfer time limit, the TC/DSC has to be returned to the cask handling area to be positioned in vertical orientation and then the TC/DSC annulus will be filled with clean water. As discussed in Section 4.5.4, a total of 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months is available to complete Action A.2 and Action A.3 of the LCO 3.1.3 of the Technical Specifications [B.43] with a maximum duration of 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months for Action A.2.

The allowable duration for the transfer operations (defined as from the time when the water in the TC-DSC annulus is drained to when the DSC is loaded into the storage module) will vary depending only on the DSC type and the heat load configuration.

For simplicity of operations, a single time limit is used for all ambient conditions and TC orientations (i.e., longer times are available for the non-controlling conditions).

The following table summarizes the permissible operational conditions:

DSC Heat Load Zoning Configuration Transfer Time Limit (1), (2) (4)

HLZCs 1, 2,3, 4 and 9 (5) ( 22 kW)

No time limit HLZCs 5, 6 ( 31.2 kW) 23.0 Hours (3)

HLZCs 7, 10 (5) ( 31.2 kW) 10.0 Hours (3)

HLZC 8 ( 27.4 kW) 23.0 Hours (3)

Notes:

(1) Transfer time is defined as from the time when the TC/DSC annulus water is drained to when the DSC is loaded into the storage module.

(2) The listed allowable transfer times are valid for all ambient conditions and TC orientations.

(3) Initiate recovery operations such as air circulation if the operation time exceeds the limit per LCO 3.1.3 of Technical Specifications [B.43].

(4) The transfer operation time limit is reset only if the transfer cask annulus is refilled with water.

(5) Thermal evaluation of 61BTH DSC for HLZCs 9 and 10 is presented in Section T.4.6.10 of [B.42].

B.4.5.2 61BTH DSC Thermal Analysis There is no change to the thermal analysis of the 61BTH DSC for transfer operations described in Appendix T, Section T.4.6 of [B.42].

B.4.5.2.1 Heat Load Zoning Configurations There is no change to the HLZCs allowed within the 61BTH Type 2 DSC. A total of 10 HLZCs are allowed for the 61BTH DSCs as shown in Figure 4A through Figure 4J of the Technical Specification [B.43]. Thermal evaluation of the 61BTH Type 2 DSC with HLZCs 1 through 8 are presented in Appendix T, Section T.4.6.1 through Section T.4.6.9 of [B.42].

Thermal evaluation of the 61BTH Type 2 DSC for HLZCs 9 and 10 is presented in Appendix T, Section T.4.6.10 of [B.42].

All Indicated Changes are in response to RAI 4-7

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.4-29 Appendix B is newly added in Amendment 2.

B.4.5.4 Thermal Analysis of 61BTH DSC with up to 61 Damaged FAs There is no change to the thermal evaluation of 61BTH Type 2 DSC with up to 61 damaged FAs presented in Appendix T, Section T.4.6.11 of [B.42].

Figure 5 of the Technical Specification [B.43] shows that the 61BTH DSC allows for the storage of up to 61 damaged fuel assemblies. For the worst case with 60 damaged FAs and one intact FA, the maximum fuel cladding temperature for intact FA is 955 °F. However, for all evaluations with intact FAs, the maximum fuel cladding temperatures are well below the limit of 1058 °F. For the case with 61 damaged fuel assemblies, since all damaged fuel assemblies are considered as rubble, there are no thermal limits associated with this scenario. Therefore, there is no impact on loading damaged fuel along with intact fuel within the 61BTH Type 2 DSC.

B.4.5.5 Thermal Evaluation for Loading/Unloading Conditions There is no change to the thermal evaluation for loading and unloading conditions presented in Appendix T, Section T.4.7 of [B.42].

B.4.5.5.1 Maximum Fuel Cladding Temperature during Vacuum Drying There is no change to the thermal evaluation during vacuum drying operations presented in Appendix T, Section T.4.7.1 of [B.42].

Tables T.4-25 and T.4-27 of [B.42] provide the maximum calculated temperatures for the fuel cladding and the basket components for the 61BTH Type 2 DSC during vacuum drying.

The maximum cladding temperatures for vacuum drying using helium are 598 °F for the 61BTH Type 2 DSC. This maximum cladding temperature is well below the limit of 752 °F [B.42].

B.4.5.5.2 Evaluation of Thermal Cycling of Fuel Cladding during Vacuum Drying, Helium Backfilling and Transfer There is no change to the discussion on thermal cycling of fuel cladding during vacuum drying operations presented in Section T.4.7.2 of [B.42].

B.4.5.5.3 Reflooding Evaluation There is no change to the discussion on unloading operations presented in Section T.4.7.3 of [B.42].

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B.4.5.6 Minimum Duration to Operate Force Air Circulation (FC)

Section B.4.5.1.4 summarizes the transfer time limits for OS197FC-B TC loaded with 61BTH Type 2 DSC with heat loads > 22.0 kW and 31.2 kW. If the transfer time limit cannot be satisfied, one of the recovery actions is to initiate Forced Air Circulation (FC). This section provides a thermal evaluation to establish the minimum duration for FC once initiated, and the subsequent transfer time limit once the air circulation is turned off to complete the transfer of the DSC into the storage module or return the DSC to the fuel handling building and refill the TC/DSC annulus with water.

Section B.4.5.6.1 presents a discussion on the various load cases considered in the thermal evaluations to determine the FC operation time. Section B.4.5.6.2 presents a description of the thermal CFD model used in this evaluation, Section B.4.5.6.3 discusses the results, and Section B.4.5.6.4 presents the applicable time limits for transfer.

B.4.5.6.1 Description of Load Cases Based on the discussion in Section B.4.5.1, air circulation is used if the total heat load is > 22.0 kW and 31.2 kW for the OS197 TC. HLZCs 5, 6, 7, 8 and 10 can be loaded with maximum decay heat loads > 22.0 kW based on LCO 3.1.3 of Technical Specifications [B.43]. As discussed in Section B.4.4.1, HLZC 7 is the bounding HLZC among the five HLZCs (5, 6, 7, 8 and 10) and is thus used in this evaluation.

The load cases considered to establish the operational time limit of the FC include the initial steady-state evaluations with the OS197FC-B TC in vertical orientation loaded with 61BTH Type 2 DSC inside the fuel handling building, followed by three stage horizontal transient transfer evaluation for 27 hours3.125e-4 days 0.0075 hours 4.464286e-5 weeks 1.02735e-5 months with and without air circulation outside the building. The air circulation generates a flow rate of 400 cfm or greater and is described in Section B.4.5.1. A GCI study is also performed using a finer mesh to evaluate the mesh sensitivity. The Load Cases (LC) are discussed below and listed in Table B.4-9.

LC 1 is the initial steady state evaluation for the OS197FC-B TC in vertical orientation inside the fuel handling building during loading of the 61BTH Type 2 DSC with the TC/DSC annulus filled with water at 223°F and indoor ambient temperature of 120°F. Similar to Section T.4.5 of [B.42], a TC thermal model in horizontal orientation is assumed for the steady state evaluation of the TC vertically placed inside the fuel handling building.

LC 1-1 is the 15 hour1.736111e-4 days 0.00417 hours 2.480159e-5 weeks 5.7075e-6 months horizontal transient transfer analysis outside the fuel handling building with outdoor ambient temperature of 100°F and without any air circulation.

The clock starts (t=0) when the TC is in the vertical orientation inside the fuel handling building and the TC/DSC annulus water is drained. During this LC, the TC is placed on the transfer skid in the horizontal orientation and moved outdoors. The results from LC 1 are used as initial condition for LC 1-1.

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LC 1-2 is the 8 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months horizontal transient transfer analysis outside the fuel handling building with outdoor ambient temperature of 100°F and forced air circulation. The results from LC 1-1 are used as initial condition for LC 1-2. LC 1-2 will establish that 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months is the minimum duration for which the FC should be kept in operation.

LC 1-3 is the 4 hour4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months horizontal transient transfer analysis outside the fuel handling building with outdoor ambient temperature of 100°F without any air circulation. The results from LC 1-2 are used as initial condition for LC 1-3. If air circulation is initiated as a recovery operation during transfer, it needs to be turned off before transferring the DSC to the storage module. LC 1-3 establishes the time available to complete the transfer operation once the FC is turned off.

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B.4.5.6.3 Results Temperature Calculations The maximum temperatures of the key components of the OS197FC-B TC loaded with 61BTH Type 2 DSC with HLZC 7 for the various load cases described in Table B.4-9 are reported in Table B.4-10.

Figure B.4-10 shows the temperature history of the fuel cladding during the transient transfer operations for LCs 1-1, 1-2 and 1-3. As seen from Figure B.4-10, during LC 1-2 the air circulation slows down the heat up rate of the TC loaded with the DSC.

Temperatures reported in Table B.4-10 show that the temperatures of all key components remain below allowable limits at the end of FC. Based on LC 1-2 analysis, the air circulation must be operated for at least 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months to cool down the TC/DSC system once initiated.

Based on LC 1-3, a maximum of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is allowed to complete the transfer of the 61BTH Type 2 DSC to the storage module or to re-establish the air circulation.

Table B.4-10 shows that the temperatures for all LCs remain below the maximum allowable temperature limits discussed in Section B.4.2.

Figure B.4-11 through Figure B.4-13 show the temperature contours for LCs 1-1 through 1-3.

GCI Calculation Following the methodology discussed in Section A.4.4.2.3.7, GCI is calculated in Table B.4-11 based on the fine (LC 2-1) and coarse (LC 1-1) meshes. As shown in Table B.4-11, the GCI based on the coarse mesh is 7.2 ºF. The maximum fuel cladding temperature including the GCI for the coarse mesh is 677.6 ºF, remaining below the temperature limit of 752 ºF.

B.4.5.6.4 Discussion of Applicable Time Limits The transfer time limit for the OS197FC-B TC loaded with HLZC 7 with maximum heat load of 31.2 kW is 13 hours1.50463e-4 days 0.00361 hours 2.149471e-5 weeks 4.9465e-6 months and an additional 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months is considered to initiate FC as a recovery option if the operation time exceeds the transfer time limit of 13 hours1.50463e-4 days 0.00361 hours 2.149471e-5 weeks 4.9465e-6 months as reported in Appendix T.4.5.4 of [B.42]. Based on the results of LC 1-1 in Section B.4.5.6.3, at the end of the 15 hours1.736111e-4 days 0.00417 hours 2.480159e-5 weeks 5.7075e-6 months transient transfer operation, the maximum fuel cladding temperature reaches 670ºF with sufficient margin to the fuel cladding temperature limit of 752ºF. However, a time limit of 13 hours1.50463e-4 days 0.00361 hours 2.149471e-5 weeks 4.9465e-6 months reported in Appendix T.4.5.4 of [B.42] is further reduced by 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months in this application for a transfer time limit of 10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months to provide an additional margin to the temperature limit for both the vertical transfer operations within the fuel building and horizontal transfer operations that occur outside the building and to maintain consistency among operations with the EOS-37PTH/EOS-89BTH DSCs. The maximum fuel cladding temperature at 10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months after the start of operations is 643°F for LC 1-1. Further, this reduction in the time limit will ensure that sufficient time is provided to initiate the recovery actions.

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If transfer operations cannot be completed within the time limit of 10 hours1.157407e-4 days 0.00278 hours 1.653439e-5 weeks 3.805e-6 months and the TC/DSC is in a horizontal orientation, one of the recovery actions is to initiate air circulation within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months .

If air circulation is initiated as a recovery operation, it must be maintained for a minimum duration of 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months before it is turned off. Once the air circulation is terminated, the DSC transfer to the storage module must be completed within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months . The maximum fuel cladding temperature at 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months after the air circulation is turned off is 692°F with sufficient margin to the temperature limit of 752°F.

The minimum duration of 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months to run the blower and the time limit of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months after the blower is turned off for completion of the transfer operations are determined based on the 61BTH Type 2 DSC in the OS197FC-B TC with the maximum allowable heat load of 31.2 kW. These time limits to initiate the recovery actions also apply to other HLZCs with heat loads > 22.0 kW and 31.2 kW. However, if the maximum heat load of the DSC is less than 31.2 kW, new time limits can be determined to provide additional time for these transfer operations.

All Indicated Changes are in response to RAI 4-7

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.4-37 Appendix B is newly added in Amendment 2.

B.4.7 References B.41 NUREG-1536, Standard Review Plan for Spent Fuel Dry Cask Storage Systems at a General License Facility, Revision 1, U.S. Nuclear Regulatory Commission, July 2010.

B.42 TN Americas LLC, Updated Final Safety Analysis Report for the Standardized NUHOMS Horizontal Modular Storage System for Irradiated Nuclear Fuel, Revision 18, USNRC Docket No. 72-1004.

B.43 CoC 1042, Appendix A, NUHOMS EOS System Generic Technical Specifications, Amendment 2.

B.44 Perry, R. H., Chilton, C. H., Chemical Engineers Handbook, 5th Edition, 1973.

B.45 GESC NS-3, NAC International, Atlanta Corporate Headquarters (Test Report NS-3-001, NAC International (while BISCO Products, Inc.), Norcross, GA.

B.46 GESC, NAC International, Atlanta Corporate Headquarters, 655 Engineering Drive, Norcross, Georgia, (Engineering Report #NS3-020, Effects of 1300 °F on Unfilled NS-3, NAC International (while Bisco Products, Inc.), Norcross, GA, 11/November 1984)

B.47 ACI 349 06, Code Requirements for Nuclear Safety Related Concrete Structures American Concrete Institute.

B.48 NUREG-2174, Impact of Variation in Environmental Conditions on the Thermal Performance of Dry Storage Casks - Final Report, U.S. Nuclear Regulatory Commission, March 2016.

B.49 Title 10, Code of Federal Regulations, Part 71, Packaging and Transportation of Radioactive Material, 2003.

B.410 SINDA/FLUINT', Systems Improved Numerical Differencing Analyzer and Fluid Integrator, Version 4.7, Cullimore & Ring Technologies, Inc., Littleton, CO, 2004.

B.411 Thermal Desktop', Version 4.7, Cullimore & Ring Technologies, Inc., Littleton, CO, 2004.

B.412 SOLIDWORKS 2016 x64 Edition SP05.

B.413 ANSYS ICEM CFD, Version 17.1, ANSYS, Inc.

B.414 ANSYS FLUENT Users Guide, Version 17.1, ANSYS, Inc.

B.415 ANSYS Design Modeler, Version 17.1, ANSYS, Inc.

All Indicated Changes are in response to RAI 4-7

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.4-46 Appendix B is newly added in Amendment 2.

All Indicated Changes are in response to RAI 4-7 Proprietary Information on Pages B.4-46 through B.4-48 Withheld Pursuant to 10 CFR 2.390

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.4-63 Appendix B is newly added in Amendment 2.

All Indicated Changes are in response to RAI 4-7 Proprietary Information on Pages B.4-63 through B.4-70 Withheld Pursuant to 10 CFR 2.390

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.6-5 Appendix B is newly added in Amendment 2.

B.6.2.5 Blended Low Enriched Uranium Fuel No change to Section 6.2.5.

B.6.2.6 Reconstituted Fuel The analysis in Section 6.2.6 justifies a negligible impact on dose rates for the EOS-89BTH DSC within the EOS-TC125. The analysis is performed for up to five stainless steel reconstituted rods per fuel assembly and 100 rods per DSC, and the reconstituted fuel assemblies are located in inner basket locations. If the 61BTH DSC were loaded with reconstituted fuel assemblies using the same loading assumptions, the impact on OS197 TC dose rates would also be negligible. For the 61BTH DSC, the maximum number of irradiated stainless steel rods is conservatively reduced to 40 per DSC. The dose rate impact of allowing a larger quantity of irradiated stainless steel rods (i.e., > 5 rods per FA or > 40 rods per DSC) or of allowing FAs containing irradiated stainless steel rods to be placed in the peripheral zone may be addressed with a site-specific analysis.

B.6.2.7 Irradiation Gases The quantity of gas generated by irradiation is 20.2 g-moles per fuel assembly, see Section T.4.6.6.4 of [B.6-4].

B.6.2.8 Justification for Reasonably Bounding Source Term Methodology No change to Section 6.2.8.

All Indicated Changes are in response to RAI 6-4

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.6-9 Appendix B is newly added in Amendment 2.

B.6.4 Shielding Analysis B.6.4.1 Computer Codes MCNP5 v1.40 is used in the shielding analysis [B.6-1]. MCNP5 is a Monte Carlo transport program that allows full 3D modeling of the HSM-MX. Therefore, no geometrical approximations are necessary when developing the shielding models.

B.6.4.2 Flux-to-Dose Rate Conversion No change to Section 6.4.2.

B.6.4.3 OS197 TC Dose Rates Normal Conditions Dose rates are computed using mesh tallies similar to the mesh tallies utilized in the EOS-TC125 models to facilitate dose rate comparisons. To simplify the presentation, only maximum total dose rates are reported at or near the surface of the OS197 TC in Table B.6-13. This table provides dose rates for transfer and transfer peak.

Transfer dose rates correspond to the tally structure shown in Figure 6-7. Using this tally structure, the bottom and top tallies correspond to the entire bottom or top surface, and the side tallies are circumferential averages around the entire cask. The transfer peak dose rates are computed using a more refined tally structure, as indicated in Figure 6-8 through Figure 6-10. In the refined tallies, the top and bottom tallies have six annular regions, and the side tallies have 24 angular regions. While Figure 6-7 through Figure 6-10 depict the EOS-89BTH DSC within the EOS-TC125, the tally locations are similar for the OS197 TC.

The OS197 TC dose rates reported in Table B.6-13 are highly conservative due to the hybrid HLZC assumption (see Figure B.6-1). Due to the large neutron sources in each zone, approximately 40% of the dose rate at the side of the OS197 is due to fuel assemblies in the inner zones. If HLZC 1 through 10 were modeled explicitly, the dose rates would decrease compared to the hybrid HLZC.

The OS197 TC and EOS-TC125(89BTH) dose rates are compared in Table B.6-14.

The dose rates computed for the OS197 TC are bounded by the EOS-TC125(89BTH) dose rates on the top and side, where the majority of operations occur. Dose rates are larger for the OS197 TC on the bottom of the cask, although the cask bottom is inaccessible during decontamination and welding operations.

Occupational exposure for transfer of the EOS-89BTH DSC to the HSM-MX is provided in Table A.11-4. In the OS197 TC occupational dose assessment provided in Section B.11.2.1, EOS-TC125(89BTH) dose rates are conservatively applied for decontamination and welding operations, and OS197 TC dose rates are applied for transfer operations.

All Indicated Changes are in response to RAI 11-1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.8-3 Appendix B is newly added in Amendment 2.

B.8.2 Materials Selection This section discusses the materials used in the components of the NUHOMS-61BTH Type 2 DSC and OS197 TC to be used in the NUHOMS MATRIX (HSM-MX) system. No change to section A.8.2 for the HSM-MX.

B.8.2.1 Applicable Codes and Standards and Alternatives No change to Appendix T, Section T.3.1.2.1 and T.3.1.2.2. ASME Code Alternatives for the 61BTH Type 2 DSC are provided in Section 4.4.4 of the Technical Specifications.

No change to Chapter A.8, Section A.8.2.1.3 for the HSM-MX.

No change to Chapter 3, Section 3.2.5.3 or Chapter 4, Section 4.9 and Table 4.9-1 of CoC 1004 [B.8-2] for the OS197 TC.

B.8.2.2 Material Properties No change to Appendix T, Section T.3.3 of CoC 1004 [B.8-2] for the 61BTH Type 2 DSC and OS197 TC.

Material properties of the OS197 TC are provided in Table 8.1-3 of CoC 1004 UFSAR

[B.8-2]. In cases where multiple material options are allowed, the material properties used for analysis are provided. There are no changes to the material properties as provided in Table 8.1-3. The shell, inner liner, top cover plate, and bottom cover plate use ASME material SA-240 Type 304 (row 1); alternatively, the shell and top cover plates may be SA-516 Gr. 70 (row 4). The top flange and bottom support ring/bottom flange use ASME SA-182 F304N (row 9). The lower trunnions are constructed from ASME SA-479, Type 304. The lower trunnion sleeve may be fabricated from ASME SA-516 Gr. 70 (row 4) or SA-508 Cl. 1A. The upper trunnion is fabricated from ASME SA-533 Gr. B, Cl. 2 or SA-508, Cl. 3A (row 8). Additionally, one option for the upper trunnion uses ASME SA-182 Type FXM-19 (row 2). The lead gamma shielding is provided by ASTM B29 Chemical Copper Lead (row 15), and the transfer cask top cover plate bolts are SA-193 B7 (row 14).

No change to Chapter A.8, Section A.8.2.2 for HSM-MX.

B.8.2.3 Materials for ISFSI Sites with Experience of Atmospheric Chloride Corrosion No change to Chapter A.8, Section A.8.2.3.

B.8.2.4 Weld Design and Inspection No change to Appendix T, Section T.3.1.2.1 of CoC 1004 [B.8-2] for 61BTH Type 2 DSC.

No change to Chapter A.8, Section A.8.2.4 for HSM-MX.

RAI 8-2 RAI 8-1 & RAI 8-2

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.11-1 Appendix B is newly added in Amendment 2.

B.11 RADIATION PROTECTION This chapter describes the design features of the NUHOMS MATRIX (HSM-MX),

OS197 TC, and 61BTH Type 2 DSC that maintain radiation exposure to site personnel as low as reasonably achievable (ALARA), as well as minimize exposure to the public. Radiation exposures to offsite individuals computed for both normal and accident conditions of an independent spent fuel storage installation (ISFSI) for the EOS-DSC are conservatively applied to the 61BTH DSC.

This chapter provides an example of how to demonstrate compliance with the relevant radiological requirements of 10 CFR Part 20 [B.11-1], 10 CFR Part 72 [B.11-2], and 40 CFR Part 190 [B.11-3]. Each user must perform site-specific calculations to account for the actual layout of the HSM-MXs and fuel source.

All Indicated Changes are in response to RAI 11-1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.11-3 Appendix B is newly added in Amendment 2.

B.11.2 Occupational Dose Assessment This section provides estimates of occupational dose for the OS197 TC and ISFSI loading operations. Assumed annual occupancy times, including the anticipated maximum total hours per year for any individual, and total person-hours per year for all personnel for each radiation area during normal operation and anticipated operational occurrences, will be evaluated by the licensee in a 10 CFR 72.212 evaluation to address the site-specific ISFSI layout, inspection, and maintenance requirements. In addition, the estimated annual collective doses associated with loading operations will be addressed by the licensee in a 10 CFR 72.212 evaluation.

B.11.2.1 61BTH DSC Loading, Transfer, and Storage Operations The dose rates for the 61BTH DSC within the OS197 TC are similar to the dose rates for the EOS-89BTH DSC within the EOS-TC125 on the top and side, see the discussion in Section B.6.4.3. Therefore, the decontamination and welding dose rates for the EOS-89BTH DSC within the EOS-TC125 from Table 11-1 are conservatively applied for the OS197 TC occupational dose assessment. Transfer dose rates for the OS197 TC and HSM-MX front average dose rates are obtained from the analysis documented in Chapter B.6. Dose rates used as input for the occupational dose assessment are provided in Table B.11-1. Dose rate locations around the cask are analogous to the EOS-TC125 dose rate locations illustrated in Figure 11-1.

The estimated occupational exposures to ISFSI personnel during loading, transfer, and storage operations (time and number of workers may vary depending on individual ISFSI practices) are provided in Table B.11-2. The total exposure is 2.3 person-rem.

The exposure provided is a bounding estimate. Measured exposures from typical NUHOMS System loading campaigns have been 600 mrem or lower per canister for normal operations, and exposures for the HSM-MX are expected to be similar.

Regulatory Guide 8.34 [B.11-4] is to be used to define the onsite occupational dose and monitoring requirements.

B.11.2.2 61BTH DSC Retrieval Operations Occupational exposures to ISFSI personnel during 61BTH DSC retrieval are similar to those exposures calculated for 61BTH DSC insertion. Dose rates for retrieval operations will be lower than those for insertion operations due to radioactive decay of the spent fuel inside the HSM-MX. Therefore, the dose rates for 61BTH DSC retrieval are bounded by the dose rates calculated for insertion.

B.11.2.3 Fuel Unloading Operations No change to Section 11.2.3.

All Indicated Changes are in response to RAI 11-1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.11-8 Appendix B is newly added in Amendment 2.

Table B.11-1 Occupational Dose Rates, OS197 with 61BTH DSC Dose Rate Location Averaged Segments(1)

Config.

Dose Rate (mrem/hr)

DRL1 A1-18, R11 Decon.

62 DRL2 A3-16, R10 Decon.

181 A3-16, R10 Transfer 186 DRL3 A17, R9 Decon.

98 A17, R9 Welding 113 A17, R9 Transfer DRL4 A3-11, R9 Decon.

DRL5 A1-18, R10 Transfer 147 DRL6 A17-18, R9 Transfer 13 DRL7 A17-18, R10 Transfer 21 DRL8 A2, R9 Transfer DRL9 A19, R0 Transfer 204 DRL10 A1, R10 Transfer 61 HMX-MX (HMX)

Front face surface average 41 (1) Dose rate locations analogous to Figure 11-1.

All Indicated Changes are in response to RAI 11-1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.11-9 Appendix B is newly added in Amendment 2.

Table B.11-2 Occupational Dose Rates, OS197 with 61BTH DSC (2 Sheets)

No.

Operation Configuration Dose Rate Location No. of People Duration (hr)

Dose Rate (mrem/hr)

Dose (person-mrem)

% of Total Dose 1

Drain neutron shield if necessary. Place an empty 61BTH DSC into an OS197 TC and prepare the OS197 TC for placement into the spent fuel pool.

N/A N/A 6

4.00 0

0 0%

2 Move the OS197 TC containing a 61BTH DSC without fuel into the spent fuel pool.

N/A N/A 6

1.50 0

0 0%

3 Remove a loaded OS197 TC from the fuel pool and place in the decontamination area.

Refill neutron shield tank if necessary.

Decon.

DRL1 2

0.25 62 31 1.3%

4 Decontaminate the OS197 TC and prepare welds.

Decon.

DRL2 2

1.75 181 634 27.4%

Decon.

DRL3 2

0.50 98 98 4.2%

5 Weld inner top cover plate.

Welding DRL3 2

0.75 113 170 7.3%

6 Vacuum dry and backfill with helium.

Welding DRL3 2

0.50 113 113 4.9%

7 Weld outer top cover plate and port covers, perform non-destructive examination.

Welding DRL3 2

0.50 113 113 4.9%

8 Drain annulus. Install OS197 TC top cover.

Ready the support skid and transfer trailer.

Transfer DRL5 1

0.50 147 74 3.2%

9 Place the OS197 TC onto the skid and trailer.

Secure the OS197 TC to the skid.

Transfer DRL2 2

0.33 186 123 5.3%

10 Install retractable roller tray (RRT).

Transfer HMX 2

2.00 41 164 7.1%

11 Transfer the OS197 TC to ISFSI.

N/A N/A 6

1.83 0

0 0%

12 Position the OS197 TC inside the loading crane (MX-LC).

Transfer HMX+DRL2 2

0.50 227 227 9.8%

13 Remove forced cooling system (if used) and install the ram cylinder assembly.

Transfer DRL9 2

0.50 204 204 8.8%

14 Remove HSM-MX door.

Transfer HMX 2

0.50 41 41 1.8%

15 Remove the OS197 TC top cover.

Transfer HMX+DRL6 2

0.67 54 72 3.1%

16 Align and dock the OS197 TC with the HSM-MX. Secure the OS197 TC to the HSM-MX.

Transfer HMX+DRL7 2

0.25 62 31 1.3%

17 Transfer the 61BTH DSC from the OS197 TC to the HSM-MX using the ram cylinder.

N/A N/A 3

0.50 0

0 0%

All Indicated Changes are in response to RAI 11-1

NUHOMS EOS System Updated Final Safety Analysis Report Rev. TBD, TBD June 2020 Revision 5 72-1042 Amendment 2 Page B.11-10 Appendix B is newly added in Amendment 2.

Table B.11-2 Occupational Dose Rates, OS197 with 61BTH DSC (2 Sheets)

No.

Operation Configuration Dose Rate Location No. of People Duration (hr)

Dose Rate (mrem/hr)

Dose (person-mrem)

% of Total Dose 18 Disengage the ram and un-dock the OS197 TC from the HSM-MX.

Transfer HMX+DRL10 2

0.08 102 16 0.7%

19 Install HSM-MX access door. Move OS197 TC to the transfer skid for removal.

Transfer HMX 2

0.50 41 41 1.8%

20 Uninstall RRT.

Transfer HMX 2

2.00 41 164 7.1%

Total 2314 All Indicated Changes are in response to RAI 11-1

ML20190A142

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