ML23037A886
| ML23037A886 | |
| Person / Time | |
|---|---|
| Site: | 07109389 |
| Issue date: | 02/10/2023 |
| From: | Storage and Transportation Licensing Branch |
| To: | TN Americas LLC |
| Shared Package | |
| ML23037A884 | List: |
| References | |
| EPID L-2021-NEW-0007 | |
| Download: ML23037A886 (1) | |
Text
Request for Additional Information for the review of the Model No. TN-40HT Package Docket No. 71-9389 The TN-40HT is a dual-purpose cask designed for storage and transportation. The storage application of the TN-40HT was previously approved by the U.S. Nuclear Regulatory Commission in a site-specific license for the independent spent fuel storage installation at the Prairie Island Nuclear Generating Plant under Docket No. 72-10. This application is for approval of the TN-40HT for transportation under Title 10 of the Code of Federal Regulations (10 CFR)
Part 71.
By letter dated November 30, 2021 (Agencywide Documents Access and Management System
{ADAMS} Accession No. ML21334A171), Orano TN submitted an application for approval of the Model No. TN40-HT. On June 15, 2022, the application was accepted for detailed review with a few Observations (ADAMS No. ML22164A057 and ML22164A058).
This request for additional information (RAI) identifies information needed by the staff in connection with its detailed review of the application.
Each individual RAI describes information needed by the staff to complete its review of the application and to determine whether the applicant have demonstrated compliance with the regulatory requirements of 10 CFR Part 71.
CHAPTER 2 STRUCTURAL AND MATERIALS EVALUATION 2.1 Clarify how the vibration and fatigue analysis performed for normal conditions of transport (NCT) covers all forms of transport.
Section 2.5.5 indicates that peak inertia and vibration values are based on NUREG 766510 (rail cars). However, peak maximum acceleration values are an order of magnitude greater for truck transport according to NUREG 766510, and peak inertia values for shock are larger in the vertical direction for truck transport. Confirm and/or update calculations that support tables 2.11.4-6 and 2.11.7-1 as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.71(c)(5).
2.2 Justify the ANSYS element types SOLID45 and BEAM4 used to model the TN-40HT for NCT and hypothetical accident conditions (HAC) analysis.
Section 2.11.1.2 of the safety analysis report (SAR) and other sections state that all components are modeled using the SOLID45 element in ANSYS. SOLID45 elements are no longer recommended/supported by ANSYS (10+ years) and SOLID185 should be used instead according to ANSYS. Likewise, the BEAM4 element has been replaced by the BEAM 188 element. Verify and or update any analysis used to evaluate the package as well as the SAR as necessary.
Enclosure
This information is needed by the staff to determine compliance with 10 CFR 71.71(c)(7) and 10 CFR 71.73(c)(1).
2.3 Describe the structural integrity of the lower trunnions when used for handling operations The applicant has stated that the lower trunnions will only be used to rotate and upend the cask; however, calculations supporting this operation for the lower trunnions have not been supplied. It is unclear how the TN40-HT will perform if one or both lower trunnions were to fail when handling the TN40-HT without its impact limiters on. Update calculations and the SAR as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.45(a).
2.4 Clarify the weld symbol shown on Sheet 1 of Drawing TN40HT-71-6 in zone G7 and C7 and verify the performance of the cask with respect to dose rates in the event of an upper trunnion failure.
It is unclear if the weld symbol as shown is a 3/8 fillet weld. Supporting calculations and the drawing itself seem to indicate a much larger weld is intended at this location which connects the trunnion to the shield shell. Update any calculations/drawing as necessary.
In addition, section 2.11.13.3.2 indicates that an upper trunnion failure due to excessive load will not affect the performance of the cask since it will break away from the cask before the cask wall (shield shell) fails. While the containment boundary remains unaffected, it is unclear how dose rates are affected when the upper trunnions are no longer attached to the cask (streaming path), given the large void that would exist in this shielded region of the cask.
This information is needed by the staff to determine compliance with 10 CFR 71.33(a)(5).
2.5 Describe the condition of the transportation package due to cumulative damage from the free drop, puncture, thermal and immersion tests described for HAC conditions for a postulated scenario described below.
The applicant has not described the condition of the TN40-HT transportation package when subjected to cumulative damage for the scenario where the package undergoes a free drop (slap-down), followed by a nearly vertical end drop (see image below) for the puncture test, followed by the thermal test, and finally the immersion test.
Postulated Puncture Bar Strike Region Scenario for puncture test where puncture bar strikes tie rod region of the impact limiter Staff is concerned that the puncture test, as depicted above in the scenario figure, could partially separate or strip the impact limiter from the rest of the transportation package, making it more susceptible to subsequent thermal and immersion tests. For this scenario it is postulated:
The initial free drop (side drop or slap-down) of the package causes maximum damage (if any) to the tie rod connection plate region (Part 39 - Single Tie Rod Bracket, or Part 41 Double Tie Rod Bracket per Sheet 1 of Drawing 10421 41) in the region of the puncture bar strike depicted above. The package configuration for the free drop (slap-down) to be considered should be the most damaging with respect to the impact limiter and/or tie rod connections for subsequent puncture bar strike.
The puncture bar strikes the most susceptible part of the tie rod to impact limiter connection, or in the vicinity away from the connection plates (Part 39 - Single Tie Rod Bracket, or Part 41 Double Tie Rod Bracket per Sheet 1 of Drawing 10421-71-41) which has suffered prior damage from the free drop test mentioned above. A strike in this region could potentially rupture a tie rod or pull away a connection plate (Part 39/Part 41) from the impact limiter causing the impact
limiter to separate and expose the cask body. The applicant should determine the location which maximum damage is expected.
This information is needed by the staff to determine compliance with 10 CFR 71.73.
2.6 Confirm the dynamic load factors values used to calculate the stresses on the fuel basket due to drop tests.
Dynamic load factors calculated in section 2.11.8.3.2 of the SAR for the basket appear to have been based on natural frequencies from a similar TN-40 system for stainless steel basket components. However, it appears that the TN-40HT stainless steel components are subjected to higher heat loads (roughly 200 oF) and thus a smaller modulus of elasticity for stainless steel is expected which ultimately affects the dynamic load factor used in stress calculations. Confirm the material properties and natural frequency analysis used in the basket evaluation and update any calculations as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.71(c)(7) and 10 CFR 71.73(c)(1).
2.7 Clarify the interaction between fuel assemblies and the and cask lid, and between the basket and cask lid as a result of gaps potentially forming between these components during drop scenarios.
From the licensing drawings and analyses provided, it is unclear what gap/clearance exists or forms between fuel assemblies and the cask lid, and between the basket and the cask lid during drop scenarios. Unless dunnage or additional spacers exists between these components, gaps are expected to form between these components during a free drop or slap-down scenario, potentially causing additional stress/damage to the lid bolts and the fuel assemblies due to secondary impact/interaction of these components. Also, it is not clear how the basket is restrained relative to the cask during drop scenarios. It was noted that the TN-40 considered gaps between fuel and the cask lid.
Update the licensing drawing, SAR, calculations, and LS-DYNA models as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.71(c)(7) and 10 CFR 71.73(c)(1).
2.8 Justify the dynamic load factor figure used to determine forces on the package during a HAC side drop as described in section 2.11.8.4.1.3.
Section 2.11.8.4.1.3 states that the dynamic load factors used in evaluating the package during a HAC side drop is 1.01 and is based on Figure 2.11.8-5. However, it is unclear how this figure was generated or from what reference it was obtained since NUREG/CR-3966 (Fig 2.15) was used extensively to license the TN-40, and used elsewhere for the TN40-HT.
Additionally, it is unclear how a damping factor of 7% was determined to generate Figure 2.11.8-5 or how it replaces Fig 2.15 of NUREG/CR-3966. Figure 2.11.8-5 is not conservative when compared to Fig 2.15 of NUREG/CR-3966, where dynamic load factors between 1.08 and 1.2 were used in licensing the TN-40, nor is it conservative compared to Figure 2.11.9-6. Confirm the dynamic load factors used and update all calculations and SAR as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.73(c)(1).
2.9 Clarify and provide supporting calculations used in the fatigue and vibration analysis of the containment boundary.
Appendix 2.11.7 of the application discusses the fatigue analysis performed on the containment boundary. However, it is unclear were supporting values/and calculations were obtained/determined. Specifically:
a) With regards to Table 2.11.7-1, it is unclear what material/component limited N (cycles allowable) in the table.
b) The TN40-HT is an approved storage system, and it is unclear how previous operations during the storage such as lifting and transit to a storage pad have been considered in the fatigue analysis. For transportation, lifting has been assumed to occur only 2 per trip, yet potentially hundreds if not thousands of smaller cycles have also occurred for storage operations when carried by a vertical cask transporter.
Update fatigue calculations as necessary and note that ASME fatigue tables previously used (I-9.1) have changed since 2007.
This information is needed by the staff to determine compliance with 10 CFR 71.71(c)(5).
2.10 Clarify Detail E as called out on Sheet 1 of Drawing TN40HT-71-3.
Detail E is called out on Sheet 1 of Drawing TN40HT-71-3 and references Detail E shown on Sheet 2 of Drawing TN40HT-71-3. However, the call out on Sheet 2 does not appear to match Sheet 1. Clearances/dimensions of the region around the lid bolts and the lid itself as expected in Detail E appear to not have been included. While necessary for the construction of the cask, these details are also important in justifying how lid bolts may see little to no shear forces for certain drop scenarios such as a side drop.
This information is needed by the staff to determine compliance with 10 CFR 71.33(a)(5).
2.11 Clarify the loads applied to the lid bolts during free drops and puncture for NCT and HAC.
Appendix 2.11.4.3 of the FSAR describes the forces applied to the lid bolts for NCT and HAC tests. Specifically, it states that lid bolts do not experience any force during an end drop due to the presence of the impact limiter (IL):
Since the bolts are protected by the IL during a 90° end drop.
And therefore, the end drop scenario is not examined for the lid bolts. However, based on the licensing drawings and physics of the end drop, the contents of the cask and the lid itself will observe forces for several reasons:
- 1) There is a gap between the impact limiter spacer and the lid according to Detail 1 on Sheet 1 of Drawing TN40HT-71-2. During an end drop where the lid and attached impact limiter strike the unyielding surface, the impact limiter will engage the impact limiter spacer, which in turn will engage the lid, causing forces
to be exerted on the lid bolts in addition to the contents bearing down on the lid itself. It has been noted in past physical testing that lid bolts have failed even in end drop scenarios where the lid was not struck directly.
- 2) A quasi-static analysis has been assumed, where a dynamic load factor and rigid body assumption was used to evaluate side and end drop scenarios for NCT and HAC. This implies that g-forces from drop tests will always be present over the entire cask as transmitted by impact limiters.
Update the calculations (forces, stresses, factors of safety etc.) as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.71(c)(7) and 10 CFR 71.73(c)(1).
2.12 Clarify the use of threaded inserts for lid bolts.
Section 2.11.4.5 of the SAR states: if threaded inserts are used, then this analysis is considered bounding, as the threaded inserts will have higher mechanical properties than the cask forged body).
However, it does not appear that threaded inserts are indicated on the licensing drawings, or elsewhere in the SAR, and it is unclear what higher mechanical properties are. Clarify the SAR and drawings as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.33(a)(5).
2.13 Justify the ASME code years used to evaluate the TN40-HT.
Chapters 1 and 2 of the SAR use ASME Boiler and Pressure Vessel Code,Section III, Division 1, 2004 through 2006 addenda to evaluate the TN40-HT However, section NCA-1140 of ASME BPVC Section III states in part:
(2) In no case shall the Code Edition and Addenda dates established in the Design Specifications be earlier than: (-a) 3 yr prior to the date that the nuclear facility construction permit application is docketed or filed with the regulatory authority It appears that the code years used in the application are earlier than 3 years of the original docketing for this new package. Relative to the latest edition of the Code (2021),
the code has changed significantly in a manner which is not necessarily conservative (e.g. fatigue tables (I-9.1)). Update the FSAR and calculations as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.31(c).
2.14 Clarify if all licensing drawings have been included in the application.
Note 1 of Drawing TN40HT-71-2 states that impact limiter assembly drawings are depicted in Drawings 10421-71-40 to Drawing 10421-71-44. However, it does not appear that Drawing 10421-71-40 was provided. In addition, Drawing 10421-71-7 references Drawing 10421-71-2, but Drawing 10421-7-2 does not appear to have been provided either.
This information is needed by the staff to determine compliance with 10 CFR 71.33.
2.15 Describe the condition of the aluminum inserts that are bolted to the basket after NCT and HAC drop tests.
Section 3.3.1.1 of the SAR states that the aluminum inserts provide a conduction path for heat dissipation (Sheet 1 of Drawing TN40HT-71-8). However, it is unclear how the package will perform thermally if any of them were to get damaged or detach from the basket in the event of a drop, as no supporting calculations appear to have been provided. If the inserts are required to remain intact and/or attached to the rail studs post NCT/HAC drops, an analysis should be provided. Note that previous exposure to heat from a storage configuration should also be considered when defining material properties, as aluminum can soften significantly in a short period of time at the temperatures experienced inside the TN40-HT under storage conditions. Update drawings, calculations and the SAR as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.73(c)(4), 10 CFR 71.71(c)(7) and 10 CFR 71.73(c)(1).
2.16 Describe the condition of the cask when differences in mass moment of inertia relative to the original licensing basis (TN-40) is considered in evaluating the TN-40HT for free drops such as the slap-down scenario for HAC.
The applicant considered differences in mass and other physical quantities between the TN-40 cask and the TN-40HT when making a safety case for the TN-40HT for the slap-down scenario for HAC. However, it does not appear that differences in mass moment of inertia were examined in this comparison. Free drops that include cask rotation (slap-down) could be affected by the difference of mass moment of inertia and resulting g-loads. Currently it is assumed that the 20o slap-down scenario is bounding but it is unclear if it is since the effect of mass moment of inertia was not considered.
Confirm/update the calculations and SAR as necessary.
This information is needed by the staff to determine compliance with 10 CFR 71.73(c)(1).
2.17 Provide information regarding thermal spray in the drawings, and in periodic maintenance in SAR chapters 8 or 9.
A package must be made of materials and construction that assure that there will be no significant chemical, galvanic, or other reaction among the packaging components, among package contents, or between the packaging components and the package contents, including possible reaction resulting from inleakage of water, to the maximum credible extent. Account must be taken of the behavior of materials under irradiation.
This information is needed by the staff to determine compliance with 10 CFR 71.35(a) and 10 CFR 71.43(d).
CHAPTER 3 THERMAL EVALUATION 3-1 Clarify in section 3.4 of the SAR, the insolation values and duration of application used during the HAC post-fire analysis and provide justification if the values used are different from those in 10 CFR Part 71.71(c)(1).
It has not been clearly described in section 3.4 of the SAR what the insolation values are during the HAC post-fire analysis, how the insolation values are applied, and justified if those values are different from the values in 10 CFR 71.71(c)(1) (i.e., applied over 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> versus 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> in 10 CFR 71.71(c)(1)).
This information is needed by the staff to determine compliance with 10 CFR 71.71(c)(1) and 71.73(c)(4).
3-2 Provide clarification of the term maximum average cavity gas temperature that is described in section 3.3.4 of the SAR.
The meaning of the term, Maximum average cavity gas temperature, that is described in section 3.3.4 of the SAR is not clear.
This information is needed by the staff to determine compliance with 10 CFR 71.71(c)(1).
3-3 Provide the maximum temperatures and the associated maximum allowable temperature limits for the aluminum components and basket poison plates during NCT and HAC.
The maximum temperatures and the associated maximum allowable temperature limits of the aluminum components (i.e., the basket slotted aluminum plates, and the aluminum alloy neutron shield tubes), and basket poison plates should be provided in chapter 3 of the SAR and in the appendix 3.6.1 maximum temperature tables.
This information is needed by the staff to determine compliance with 10 CFR 71.71(c)(1) and 71.73(c)(4).
3-4 Clarify in section 3.4 of the SAR the post-fire boundary conditions, such as the ambient temperature, that the package is in still air, and that the initial temperatures are from the end of the thermal fire HAC. Also describe in sections 3.3.2 and 3.3.3 of the SAR that during NCT conditions the package is in still air.
The post-fire thermal boundary conditions were not completely described in section 3.4 of the SAR. It was also not clear in the SAR that the package was in still air during NCT.
This information is needed by the staff to determine compliance with 10 CFR 71.43(g),
71.71(c)(1) and 71.73(c)(4).
CHAPTER 4 CONTAINMENT EVALUATION 4.1 Provide the calculation package(s) that provide(s) additional detail on the determination of the allowable reference air leakage rates for the TN-40HT package.
In order for the staff to verify the values provided in the SAR, specifically those provided in table 4-3 of the SAR and how those values were used in the release calculation in section 4.4, the full calculation package that supports the values presented in the SAR should be provided.
This information is needed by the staff to determine compliance with 10 CFR 71.51(a)(1) and 10 CFR 71.51(a)(2).
4.2 Clarify what the maximum allowable temperature is for the seals on the TN-40 HT package and report the value accurately throughout the SAR.
In tables 3-1 and 3-3 of the SAR, a maximum seal temperature of 536 °F is listed.
Sections 3.2.2, 3.6.1.3 and 4.1.1.3 of the SAR all cite the allowed long-term limit for seals is also 536 °F; however, section 7.16.1 of the SAR states that the seal temperature limit is 644 °F. In addition, the reported temperature values for NCT and HAC in this section appear to be incorrect.
This information is needed by the staff to determine compliance with 10 CFR 71.51(a)(1) and 10 CFR 71.51(a)(2).
4.3 Provide a revision of the allowable release rate calculation for HAC.
In section 4.4.2 Hypothetical Accident Conditions (SAR Page 4-14) an allowable release rate for HAC conditions is calculated by the applicant. The value used for Lu in the calculation (2.68x10-3 cm3/sec) is not found elsewhere in the SAR and it appears that the value for LA on Page 4-13 (2.561x10-4 cm3/sec) should be used for Lu in this calculation.
This information is needed by the staff to determine compliance with 10 CFR 71.51(a)(2).
ML23037A884; ML23037A886 OFFICE NMSS/DFM/STLB NSIR/DPR NMSS/DFM/CTCFB NMSS/DFM/MSB NAME PSaverot PS JGoodridge JG DMarcano DM TBoyce TB DATE Feb 6, 2023 Feb 8, 2023 Feb 9, 2023 Feb 8, 2023 OFFICE NMSS/DFM/STLB NMSS/DFM/STLB NAME YDiaz-Sanabria YD PSaverot PS DATE Feb 10, 2023 Feb 10, 2023