ML23257A091
| ML23257A091 | |
| Person / Time | |
|---|---|
| Site: | 07109383 |
| Issue date: | 08/25/2023 |
| From: | GNS Gesellschaft fur Nuklear-Service mbH |
| To: | Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML23257A096 | List: |
| References | |
| EPID L-2021-NEW-0002, T1213-CO-00019 | |
| Download: ML23257A091 (1) | |
Text
Non-Proprietary Version 2510812023 Proprietary Information withheld per 1 0CFR 2.3~ to letter T1213-CO-00019 G N 5
- 1. Response on Request for additional information dated March 16 2023 Model No. CASTOR geo69 Docket-No.: 72-9383, EPID No. L-2021-NEW-0002 Non-Proprietary Version 1.0 General Information 1-1 Justify categorizing the aluminum shells of the impact limiters, and their respective welds as not important to safety on the parts list for Drawing No. 1014-DPL-38772.
The NRC's guidance in NUREGICR-6407, "Classification of Transportation Packaging and Dry Spent Fuel Storage System Components According to Importance to Safety,"
section 5. 5. 1, "Category A Items," states "The shell is a metal skin that covers the energy-absorbing material and protects that material from minor damage and weather.
In some cases, the shell may provide structural support to the impact limiter assembly."
For the steel shells and their welds to be not important to safety (i.e., not a part of the package relied on to meet the requirements in Title 10 of the Code of Federal Regulations (10 CFR) Part 71, the shells would not have to provide structural support to the foam for the impact limiters. In addition, the steel would not be relied on to ensure that the impact limiters remained attached to the package body during the tests for normal conditions of transport and hypothetical accident conditions.
This information is needed to demonstrate compliance with 10 CFR 71.47, 10 CFR 71.51(a),
10 CFR 71.55(d) and 10 CFR 71.55(e),
10 CFR 71. 71, and 10 CFR 71. 73.
Answer:
The comment is justified; the aluminum shells of the impact limiters and their respective welds are to be classified as important to safety to satisfy according to the requirements of the mentioned regulation.
The parts list and drawings are revised accordingly and provided as Appendix 1-10 in Rev. 3 of the SAR.
2.0 Structural Evaluation Note by GNS: Regarding SAR Rev. 3, Appendix 2-4 (1014-TR-00029)
Because of a material change of the PU-Foam from in the impact limiters, the assessment of the decelerations and impact forces in the Appendix 2-4 to 1014-SR-00001 (1014-TR-00029) had to be revised. Due to this, the verification of the impact limiter components is updated in the Appendix 2-4. All requirements for the impact limiters are still fulfilled.
Furthermore as a result of the new calculated decelerations and impact forces the verification of the cask and canister components is updated in Section 2.7 of 1014-SR-00001 as well as Appendix 2-1 to 1014-SR-00001 (1014-TR-00024). Only the following load cases are updated because the new calculated decelerations are higher than those previously considered:
- 9.3-m side drop at minimum temperature for the cask components
- 9.3-m side drop at minimum and maximum temperature for the canister components 1
Non-Proprietary Version 2510812023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 With the new decelerations, the integrity of the cask and canister components is still verified with sufficient safety.
2-1 Explain the methodology used for the development of the deceleration time-history (T-H) including selection of the node for recording the T-H. Using T-H plots show how much of the drop energy converted to internal energy and what was dissipated in other forms during contact. In addition, provide the displacement T-H of the point on the impact limiter closest to the rigid surface at impact along with the development of the contact area with respect to time.
This information is needed by the staff to evaluate whether the simulation model of the package reasonably replicates the response of an actual drop under the conditions required by 10 CFR 71. 71 and 71. 73.
This information is needed to demonstrate compliance with 10 CFR 71. 71 and 10 CFR 71.73.
Answer:
To provide NRC with demanded information Appendix 2-4 to the SAR Rev. 3 (1014-TR-00029) has been supplemented with explanations and time-history plots (see subsection 6.1. and Fig. A 3 - Fig A. 20).
The time-history plots are derived from a node (node number 5500001) of the rigid body of the cask located in its center of gravity. A local coordinate system is modeled at. this node (z-direction in cask axis, x-direction in line with the trunnions) to measure the respective decelerations (see following figure). The depicted time-history plots are resultant accelerations in drop direction.
Figures of the energy time-history plots including kinetic, internal, total, hourglass, damping and sliding energy as well as external work for NCT and HAC are added.
From the figures of the energy time history plots the following points can be derived:
- The kinetic energy is converted into internal energy during the calculation. At the same time as the kinetic energy reaches its minimum the internal energy reaches its maximum.
- The external work is caused by the acceleration due to acting gravity and reaches its maximum approximately at the same time as the minimum of the kinetic energy
- The hourglass energies are negligibly small compared to the other forms of energy.
- No damping energy occurs.
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- The sliding energy is small compared to the other forms of energy and always positive.
All in all, the energy time history plots are plausible. This applies to all performed calculations.
To show the time-history of the deformation of the impact limiters and the moveme_nt of the cask during the drop calculations for the calculations the following plots are added:
- Displacement time-history plots of the point on the impact limiter closest to the rigid surface in drop direction.
- Displacement time-history plots of the cask center of gravity in drop direction.
- Development of the deformation of the impact limiter contact area at various time points.
2-2 Provide a discussion of the anticipated non-linear behavior of the package and the different elements of the LS-DYNA used to capture the non-linearities in the evaluation for the 30-foot drop analysis under hypothetical accident conditions.
The applicant used LS-DYNA non-linear elements in its numerical simulation in lieu of an actual test to evaluate the 30 foot drop test for hypothetical accident conditions. To evaluate whether the model has the capability to adequately simulate the impact, the staff requires a discussion of the anticipated non-linear behavior of the package and the different elements of the LS-DYNA used to capture these non-linearities. This information is required to assure the staff that the model simulation can capture the nonlinear behavior that would occur in a drop test as required by 10 CFR 71. 73.
This information is needed to demonstrate compliance with 10 CFR 71. 73(c)(1).
Answer:
In the SAR Rev. 3 in Appendix 2-4 (1014-TR-00029) subsection 4.1.1 a discussion is provided regarding the non-linear behavior. A description of nonlinear elements implemented in the LS-DYNA models is added. The material behavior and the included non-linearities of the various components are listed. In addition, the non-linear contact types used in the calculations are depicted.
2-3 Either provide an English version of reference 5 in section 2. 1, Safety Standards of the Nuclear Safety Standards Commission (KTA) 3201.2 Components of the Reactor Coolant Pressure Boundary of Light Water Reactors Part 2: Design and Analysis 2017-11 or revise the application to use an equivalent U.S. code or standard.
The document is required to determination whether the preload on bolts and the length of engagement is sufficient.
This information is required to determine compliance with 10 CFR 71.31(c),
10 CFR 71. 71, 10 CFR 71. 73, and 10 CFR 71.45.
Answer:
The regulation will be provided along with this response.
2.1 Material Evaluation 2-4 Provide additional information on the cast iron package coatings that demonstrate coating durability and support the emissivity values credited in the thermal analysis.
SAR table 3.2-7, "Applied emissivity of the relevant components," provides emissivity values for the coated inner and outer cask body surfaces. The outer cask surface is described as having an epoxy paint, while the inner surface is described as having a 3
Non-Proprietary Version 2510812023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-00019 Thermaline coating. Neither of these descriptors is considered to provide a sufficient basis for the emissivity values, as they describe broad varieties of coatings. Provide the manufacturer data sheets or other bases to support the emissivity values in the thermal analysis.
In addition, for the Thermaline coating on the inner package surface, provide materials qualification data, manufacturer data sheets, or other bases that demonstrate the performance of the coating under the elevated heat and radiation exposures of the internal package environment.
This information is needed to demonstrate compliance with 10 CFR 71.33(a)(5) and 10 CFR 71.43(d).
Answer:
The SAR does not intend to specify particular types of coatings for the inner and outer surfaces of the cask body. Rather, only the requirements that are demanded of the coatings and that they must fulfill are to be specified.
Therefore, section 2.2.1 of the SAR is supplemented by specifications the coatings must comply with (stability, capability of decontamination, mechanical resistance and adhesion, possibility of repair, corrosion category of the environment and emission coefficient). All mentions of type designations of coatings (e.g. Thermaline) have been removed from the SAR.
2-5 Justify the maximum allowable temperatures for the containment gaskets during hypothetical accident conditions.
SAR table 3.2-9, "Temperature limits of components," provides the maximum allowable temperatures for the metallic gaskets during hypothetical accident conditions. These limits exceed the manufacturer's operating temperature limit, as described in SAR appendix 2-9, "Material Qualification, Metal Gaskets." Provide the basis for allowing the gaskets to exceed the manufacturer's operating limit.
This information is needed to demonstrate compliance with 10 CFR 71.41(a), and 10 CFR 71.51(a)(2).
Answer:
The comment is correct, the material qualification for metal gaskets omits justification for the increased temperature limits applied for HAC and short-term operations.
In SAR Rev. 3 the revised material qualification report as appendix 2-9 considers the maximum allowable short-term temperatures (370°C/500°C) for the metal gaskets in addition to the admissible service temperature range (-40°C to 250°C) for continuous operation. For Justification it is referred to the Catalog by the manufacturer Furthermore, in SAR Rev. 3, section 2.2.1 is supplemented with additional information regarding the metal gaskets intended to be used with the CASTOR geo69 package.
2-6 Justify that the fuel basket plates will have adequate fracture performance in a drop accident to maintain the assumed fuel configuration in the criticality analyses.
The SAR does not include toughness testing requirements to verify that brittle fracture will not affect the structural integrity of the basket in a drop accident. The staff notes that the criticality analysis relies on the maintenance of configuration of the neutron absorber plates and fuel assemblies.
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Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 10CFR 2.390 to letter T1213-CO-000 19 Although nonferrous materials are generally excluded from fracture acceptance testing in consensus standards (e.g., the American Society of Mechanical Engineers (ASME)
Boiler and Pressure Vessel (B&PV) Code, Division 3, WD-2300), the proprietary metal matrix composite is a non-code material that contains boron carbide ceramic particles that may diminish fracture performance relative to the conventional aluminum materials that are considered in the ASME B&PV Code.
Therefore, justify that the current acceptance testing is capable of verifying adequate impact performance or otherwise propose additional test methods and acceptance criteria, see item 8-1, below.
This information is needed to demonstrate compliance with Title 10 of the Code of Federal Regulations (10 CFR) 71.55(e) and 10 CFR 71.59(a)(2).
Answer:
The qualification report for the ***** material (1014-TR-00011 Rev. 3, Appendix 2-8 in Chapter 2.12 of the SAR) is supplemented with a discussion regarding the fracture performance. Based on a electron microscope scanning of the fracture surface after a tensile test at -40 °C it can be concluded, that brittle fracture can be excluded for the intended application (i.e. the temperature range). Fracture toughness testing is thus not applicable.
2-7 Provide the basis for the conclusion that irradiation will not affect the shielding performance of the polyethylene moderator material.
SAR section 2.2.3, "Effects of Radiation on Materials," states that the irradiation of the ultrahigh molecular weight polyethylene shielding is approximately (per SAR appendi 5-3, table 1) and concludes that this level of radiation is insignificant with respect to the loss of shielding performance.
The staff notes that the stated radiation level has been found to change the properties of polyethylene moderators. For example, gamma radiation levels above 2 x 105 Gy were considered to lead to oxidation, cross/inking and hydrogen release of ultrahigh molecular weight polyethylene [van der Ehe, 2015]. Also, a study to evaluate the use of high density polyethylene in nuclear waste storage found that radiation exposures up to 100 Mrad (1 x 106 Gy) would be expected to lead to embrittlement [Dougherty, 1983].
Given the observations of the above (and similar) studies, provide the basis for concluding that changes in polyethylene under irradiation will have no effect on shielding performance.
This information is needed to demonstrate compliance with 10 CFR 71.43(d).
References van der Ehe, K; Kommling, A.; and Wolff 0., "Neutron Radiation Shielding Material Polyethylene: Consequences of Gamma Irradiation," WM2015 Conference, March 15-19, 2015, Phoenix, Arizona.
Dougherty, 0. and Adams, J.,
"Radiation Resistance Testing of High-Density Polyethylene," Brookhaven National Laboratory, Report No. BNL-NUREG-33641, January 1983.
Answer:
We would like to draw your attention to the conclusion drawn in Ref. [van der Ehe, 2015]
stating that the detected changes of the irradiated (U)HMW-PE are not safety-relevant for the long-term neutron radiation shielding purposes. Of course, the chemical changes 5
Non-Proprietary Version 2510812023 Proprietary Information withheld per -1 OCFR 2.390 to letterT1213-CO-00019 such as oxidation and crosslinking involve a loss of hydrogen, so that less hydrogen atoms are available for the shielding purpose. However, as the observed effects were small, the results of the publication indicate that the degradation of the material properties caused by chemical reactions involving hydrogen loss is small [Kommerling, 2018]. The safety relevant function for the relevant operational service is ensured, particularly when taking into account the decay behavior of the radioactive waste over years.
References van der Ehe, K; Kommling, A.; and Wolff D., "Neutron Radiation Shielding Material Polyethylene: Consequences of Gamma Irradiation," WM2015 Conference, March 15-19, 2015, Phoenix, Arizona.
A. Kommerling, K. van der Ehe, D. Wolff, M. Jaunich, "Effect of high-dose gamma irradiation on (U)HMWPE neutron shielding materials", Radiation Physics and Chemistry, Volume 142, January 2018, Pages 29-33.
A chapter providing a brief discussion on the behavior of the moderator material under irradiation referring to [Kommerling, 2018] has be added to the material qualification report 1014-TR-00012, and is referenced in Subsection 2.2.8 of the SAR Transport.
2-8 Clarify the definition of allowable undamaged fuel contents with respect to the function of the cladding in the safety analyses.
SAR section 1. 2. 2, "Contents," states that only undamaged fuel assemblies may be loaded, and SAR section 0. 5, "Glossary," defines undamaged fuel as fuel "that can meet all fuel-specific and system-related functions."
It is unclear what fuel-specific and system-related functions the fuel must meet, as the fuel cladding does not appear to be credited with maintaining the configuration of the fuel pellets. As stated in the July 2, 2021, response to supplemental information 2-6
[Enclosure 2 to letter T1213-CO-00010], in the safety analyses the applicant assumes hypothetical reconfiguration of the high burnup spent fuel contents into justified geometric forms. If the fuel cladding does not need to maintain the configuration of the fuel pellets, then any degree of cladding damage would seem to be allowed.
Clarify the criteria that general licensees are to use to classify fuel as undamaged.
This information is needed to demonstrate compliance with 10 CFR 71.33(b)(3},
10 CFR 71.55(d)(2), 10 CFR 71.55(e)(1) and 10 CFR 71.59(a)(2)
Answer:
We apologize for the misleading response to the request for supplemental information.
The fuel cladding is credited and performs a fuel-specific as well as system-related functions:
to maintain fuel pellets configuration, to be a primary barrier to radioactive materials release, to retain fission and fill gases, and to limit fuel release under NCT.
The hypothetical fuel reconfiguration is considered under NCT and under ACT for high burn-up fuel after 20 years of storage only (according to NUREG-2224).
Subsection 1.2.2 of the SAR Rev. 3 has been adjusted accordingly.
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Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 2-9 Justify the package and canister dryness criteria with respect to the potential for corrosion of the package internals and contents and the potential to generate flammable gas (hydrogen).
SAR section 7.1.2 states that the package and canister cavities are vacuum dried to a pressure of approximately 1 kPa (about 7.5 mm Hg). Provide the basis for that threshold, including how much residual water is considered to remain within the cavities and the potential for that residual water to lead to corrosion and hydrogen generation.
This information is needed to demonstrate compliance with 10 CFR 71.43(d).
Answer:
In Rev. 3 of the SAR Subsection 7.1.2 is supplemented with further information regarding residual moisture and the pressure rise criterion. Thereby, reference is made to the discussions of "drying adequacy" in NUREG-2216 Subsection 7.4.14.2 and NUREG-2215 Subsection 8.5.15.2.3.
2-10 Provide additional information to demonstrate that the package drying criteria are adequate to prevent an unacceptable loss of cladding toughness due to hydrogen reorientation.
As described in question 2-8 above, it is unclear to the staff if the fuel cladding is credited with performing a fuel-specific or system-related function. If so, the following is requested:
SAR section 3. 6, "Thermal Evaluation for Short-term Operations, 11 includes a maximum allowable cladding temperature during short-term operations (e.g., drying) of 400 °C, citing the guidance in NRC Interim Staff Guidance (ISG)-11, Revision 3 "Cladding Considerations for the Transportation and Storage of Spent Fuel.
11 The staff notes that this limit was recommended, in part, to inhibit the formation of radial hydrides in the cladding, which may reduce the cladding's ductility and degrade its performance in a drop accident.
However, ISG-11 (which has since been incorporated NUREG-2216, section 7.4.14.2) includes a second drying recommendation to prevent hydride reorientation: limiting the thermal cycling of the cladding to fewer than 10 cycles, where the cladding temperature variations during each cycle do not exceed 65 °C (117 F). The CASTO~ geo69 SAR does not include this criterion in the short-term operation limits.
Provide the basis for allowing fuel drying operations without limits on thermal cycling, justifying that the Zircaloy-2 cladding will not undergo an unacceptable reduction in ductility due to hydride reorientation.
This information is needed to demonstrate compliance with 10 CFR 71.55(d)(2).
Answer:
Short-term operations during the fuel drying operations of the CASTOR geo69 package comprise amongst others fuel loading of the canister under water, dewatering, vacuum drying and helium backfilling of the canister interior.
During short-term operations, the maximum fuel cladding temperature is limited to 400 °C according to NUREG-2216 (section 7.4.14.2). Additionally, NUREG-2216 includes a restriction concerning the thermal cycling of the cladding to prevent an unacceptable reduction in ductility due to hydride reorientation.
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Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 After dewatering, the cladding heats up continuously during one single phase of vacuum drying without feed-in of helium. Afterwards, the cladding cools down within one single phase of vacuum drying with feed-in of helium.
By nature of this vacuum drying process, no thermal cycling of the cladding occurs.
Other operations are not associated with thermal cycling. This restriction is therefore not applicable to the CASTOR geo69 and for that reason, no corresponding restrictions for the fuel drying operations are required.
Additional explanations are added to the description of the package operations in Subsection 7.1.2 and the thermal evaluation in SAR Section 3.6.
2-11 Resolve the following incorrect or missing information in the SAR:
- a.
Several parts of the SAR state that the impact limiter housing is constructed of steel and other portions state it is constructed of aluminum:
SAR section 1. 1 states that the "...impact limiters basically consist of a steel casing filled with polyurethane foam." SAR section 5. 1. 1 states that "... both impact limiters include steel as housing and inner lying structure sheets... ".
Section 1.2.1.6, Impact limiters states The lid impact limiter (Item 90) and the bottom impact limiter (Item 95) consist of an aluminum housing with a PU-foam... ".
- b.
In SAR table 2.1-2, the Sm and Su stress value limits for SA-965 Grade FXM-19 at 120 *c appear to be incorrect.
The stress value limits appear to be consistent with the 100 *c data from the ASME B&PV Code, rather than with values that would be expected for 120 *c.
- c.
Footnote 7 in SAR table 8. 2-1 is missing This information is needed to demonstrate compliance with10 CFR 71.31 and 10 CFR 71.33.
Answer:
The information addressed is corrected or supplemented:
- a. The impact limiter housing is made of aluminum (instead of steel). The SAR has been reviewed and Rev. 3 of the SAR has been corrected with regard to this error.
- b.
In the SAR Rev. 3 the stress value limits for SA-965 Grade FXM-19 at 120 °C are corrected. Therefore, Table 2.1-2 in Section 2.1 and Tab. A 174 in Appendix 2-1 (1014-TR-00024) are revised. Furthermore, all verifications at 120 °C concerning the canister lid, which is made of SA-965 Grade FXM-19, are updated in Sections 2.6 and 2.7 as well as in Appendix 2-1 by calculating new factors of safety. Sufficient safety is still ensured. The table with corrected values is depicted below.
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- c.
The numbering of the footnotes in the table and below it differs with respect to the initial number. This has been corrected in Rev. 3 of the SAR. There are 7 footnotes numbered from 1 to 7 (not from O to 6).
3.0 Thermal Evaluation 3-1 Describe and justify the modeling of gaps in the CASTOFf! geo69 package (packaging and content) thermal models for normal conditions of transport, hypothetical accident conditions, and short-term operations, recognizing that gaps can have a large impact on temperatures and thermal perform9nce.
SAR section 3.3. 1. 7 mentions the gap between the canister and the package body and performs a gap sensitivity analysis. However, the entire system is composed of components with corresponding tolerances, including the basket, moderator rods and plates, and spacing between solid aluminum shielding elements with the basket and canister shell, all of which have corresponding gaps associated with fabrication. For example, the SAR and basket (drawing no. 1014-00-30984) appear to indicate that the basket is not welded but is fabricated from stacked fitted parts. The lack of continuous welded connections between the basket's steel and aluminum alloy components (e.g.,
structure sheets, outer sheets, shielding sheets) indicates the presence of gaps that cause thermal resistance in conducting heat transfer from the fuel's decay heat axially and radially outward through the basket.
A detailed discussion, including a sensitivity analysis, should be provided that justifies the choice of gap sizes and how the gaps are modeled in a bounding manner, recognizing there is uncertainty in tolerances and changes in fitting, including due to distortion during steady-state and transient operations (e.g., storage, vacuum drying, transfer, fire hypothetical accident conditions). In addition, discussion should include:
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- a.
details of whether the above mentioned basket design (which does not have continuous welded connections) has been satisfactorily used in other CASTOR spent fuel systems and
- b.
details of whether the thermal performance of that basket and packages similar to the CASTOR geo69 package design have been experimentally validated as part of CASTOR's experimental validation program mentioned in SAR section 3.3.1.1.
This information is needed to determine compliance with 10 CFR 71.35.
Answer:
New SAR Sections 3.3.1.3 and 3.3.3 with an extensive discussion about the modelling of gaps between cask components including tolerances and various sensitivity analyses are added to the SAR.
Additional explanations about the modelling of gaps between FA components are added to the SAR Section 3.3.1.5.2.
Additional explanations about the validation are added to the SAR Section 3. 3.1.1.
Two validation reports are added as appendixes in the SAR Section 3.7.
Thermal load test with a serial cask of CASTOR geo type with the same constructive design features compared to the CASTOR geo69 package - especially concerning the fuel basket - were performed and compared to numerical results successfully.
GNS/WTI participates in the EPRI program "Demo Cask Benchmarking" with successful comparisons of numerical with experimental results.
3-2 Discuss the ability of the fins to resist deformation during short-term operations and loading onto the transport vehicle and their ability to retain effectiveness over time due to buildup of dirt and debris.
The CASTOR geo69's performance is based on a finned transport package design.
However, there was no discussion of the robustness of the fins to resist deformation and damage during short-term operations, loading, and normal conditions of transport. In addition, it is not clear from the SAR whether the fins are a load-bearing component (i.e., either due to the tiedown system, the bearing surfaces of the transport frame, the locking mechanism or the lashing belts) when the package is in the transfer frame. In addition, there was no sensitivity analysis of thermal performance due to damaged fins and impacts of dirt or debris buildup between fins (e.g., thermal resistance, change in emissivity and absorptivity) and no discussion whether there is a need for periodic maintenance to remove dirt and debris.
This information is needed to determine compliance with 10 CFR 71.35 Answer:
During short-term operations incl. loading and NCT, any significant damage to the fins of the cask body is not applicable, as any equipment used is optimized accordingly. The fins are not load-bearing components.
Section 1.2.1 of the SAR is supplemented with the relevant information, e.g. descriptions and illustrations of the package in the transport frame and the operational features.
Furthermore, a decrease of the thermal performance due to dirt or debris between the fins is not to be assumed during NCT, since the cask is visually inspected prior to each transport. In case of any deviation from the specification the surface, especially the space between the fins shall be cleaned.
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Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 Thus, a sensitivity analysis of thermal performance due to damaged fins and impacts of dirt or debris buildup between fins is not applicable.
3-3 Perform a surface energy balance of the package's outer surface to calculate the package surface temperature during the hypothetical accident conditions fire condition so that a review of the thermal model's boundary conditions and thermal inputs (e.g.,
decay heat flux, fire input) can be performed.
SAR Figure 3.4-7 shows a package surface temperature much less than the fire temperature even though the surface experiences the thermal convection input and thermal radiation heat transfer input from the 800 °C fire. Note that the effective surface emissivity equation described in SAR section 3.4.2.1 should consider the engulfing nature of the fire (e.g., top and bottom package surfaces). The derivation of a surface energy balance will aid in understanding the interaction of the thermal inputs and boundary conditions.
This information is needed to determine compliance with 10 CFR 71.35.
Answer:
Additional explanations about the cask surface temperature during the fire phase are added to the SAR Section 3.4.2.1 (below Figure 3.4-3).
New SAR Section 3.4.4 with an energy balance calculation for the fire phase is added to the SAR.
3-4 Clarify and update the various parameters used in the pressure calculations and provide pressure information associated with low burnup fuel, which has a higher fission gas release fraction.
- a.
The fission gas release fraction fot normal conditions of transport used in the pressure calculations (e.g., SAR Tables 4.2-1, 4.2-2) used a 15% value for high burnup fuel. However, there was no indication that pressures based on high burnup fuel would bound a low burnup fuel, which is assumed to have a 30%
fission gas release fraction.
- b.
The canister and package pressure at hypothetical accident conditions (hypothetical accident conditions) impact reported in SAR table 4.3-3 and table 4.3-4 was based on a "sum of gas released from the content into the canister cavity" of 269. 9 moles. However, the sum of the "mobilized fission gas in the canister" and "mobilized fuel rod filling gas helium" is 483.2 moles (according to the values in table 4.3-3). In addition, the larger number of moles would also affect the "sum of gas released from the content into the canister and cask cavity" reported in SAR table 4.3-4 and the resulting package pressure, which may require updated containment analyses.
This information is needed to determine compliance with 10 CFR 71.35.
Answer:
- a. According to NUREG/CR-6487, a fission gas release fraction of up to 30% may be expected for low burn-up fuel.
Thus, the set of boundary conditions for pressure calculations from table 4.2-1 and 4.2-2, i.e. values for high burn-up 11
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 10CFR 2.390 to letter T1213-CO-00019 fuel, remains bounding even though individual parameters might be exceeded for low burn-up fuel.
This argumentation was included in the SAR.
- b. For "sum of gas released from the content into the canister cavity" and "sum of gas released from the content into the canister and cask cavity" the values of the HAG-fire case were mistakenly implemented in table 4.3-3 and in table. 4.3-4.
However, the pressure calculations were performed with the correct values The tables have been updated for the revised SAR.
3-5 Clarify in the SAR whether there are any time limits associated with transferring the spent fuel content between the verlical orientation (e.g., transfer cask) to the CASTO~ geo69 transporlation package (horizontal orientation).
Section 3.6 of the CASTOR geo69 transporlation SAR refers to the section 4. 7 in the CASTO~ geo69 storage SAR for thermal performance and time limits associated with short-term operations. There was no discussion associated with operations associated with the transfer between horizontal orientations (e.g., transfer package) to the CASTO~ geo69 transportation package. The operations discussed in section 4. 7 dealt with verlical canister orientations, but there was no discussion concerning horizontal orientations, which would tend to have different thermal correlations and boundary conditions. Likewise, there was no analysis or discussion relating to the content and package temperatures when the transfer cask is positioned on top of the CASTO~ geo69 package with the bottom lid closed, as described in SAR table 7.1.2 (e.g., steps G1.5 and G1.6).
This information is needed to determine compliance with 10 CFR 71.35.
Answer:
The reference to Chapter 4.7 of the storage application within Chapter 3.6 of the Transport SAR has been resolved. During short-term operations the cannister is handled by the transfer cask exclusively in vertical direction. The same is for the canister transshipment form the transfer cask into the transport and storage cask. The transport and storage cask is tilted to the horizontal position only after final closing. Thus, horizontal orientations during short-term operations are not applicable. The following Subsections are furthermore added:
New SAR Section 3.6.6 with a discussion about the transfer of the transfer cask inside the reactor building is added to the SAR.
New SAR Section 3.6.7 with a discussion about the loading of the canister into the transport and storage cask is added to the SAR.
3-6 Provide additional discussion of the UHMW-PE moderator's allowable temperature and the effect of the material being at temperatures greater than its allowable temperature.
SAR table 3. 2-9 does not provide the maximum allowable temperature of the moderator material. SAR table 3.4-2 indicates that temperatures can reach 310 °C during the HAG fire. Although SAR appendix 4-2 indicated that hydrogen generation from radiolysis would result in a small amount of hydrogen (less than*
-per year), the SAR should clarify that the UHMW-PE material does not thermally degrade during the fire such that combustible gases may form and react.
This in.formation is needed to determine compliance with 10 CFR 71.43(d).
12
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 Answer:
According to the material qualification (Appendix 2-7ofthe SAR) the service temperature of the moderator material ranges from This range is not exceeded or undercut under NCT. Under HAC fire the upper service limit is clearly exceeded, however, in the HAC shielding evaluations no credit is taken from the presence of the moderator. Therefore, no temperature limit is specified for HAC.
Thermal degradation of polyethylene starts at temperatures above 340°C [Ortner] and can therefore be ruled out under HAC fire. The revised material qualification in SAR Rev. 3 appropriately provides a brief discussion on thermal degradation of polyethylene.
[Ortner]
Dr. Ortner, Dr. Hensler Beurteilung van Kunstoffbranden Bei einer Storung des bestimmungsgema~en Betriebs entstehende Stoffe nach den Anhangen II - IV der 12. BlmSchV, Az: 1/7-1515-21294 November 1995 https://www. lfu. bayern.de/luft/doc/kunststoffbraende. pdf 3-7 Provide in the SAR the minimum and maximum allowable temperatures of the VMQ (vinyl-methyl-silicon rubber) and FKM (fluorocarbon rubber) elastomeric seals during normal conditions of transport.
SAR section 2 mentioned that VMQ and FKM seals are used during package operations. The seal allowable temperatures are needed to confirm that the seals would be operable during and after normal conditions of transport, including at cold conditions.
This information is needed to determine compliance with 10 CFR 71.35 and 10 CFR 71.51(a)(1).
Answer:
The following paragraph is added to Section 2.2:
"All elastomeric seals used are not important to safety with regard to requirements of 10 CFR 71. They are primarily used to during package operations and to protect the cask and/or components from dirt and water penetration. They are made of VMQ or FKM, which are suitable to the expected thermal and radiation conditions (c.f. Section 2.2.8).
Both VMQ and FKM have excellent resistance to high temperatures (up to 200 °C) and outstanding low temperature behavior down to <-40 °C [14]. This service temperature range is maintained during the entire package lifetime (c.f. Chapter 3)."
3-8 Provide additional discussion and justification for the water convection heat transfer parameter described in the Part 72 CASTOR geo69 SAR section 4. 7 and the water flow rate mentioned in SAR table 7. 1-1.
- a.
Section 3.6 of the CASTOR geo69 transportation SAR refers to section 4. 7 in the CASTOR geo69 storage SAR with regards to short-term operations.
Section 4. 7 of the CASTOR geo69 storage SAR indicated a 500 to 600 Wlm 2-K water convection heat transfer coefficient for short-term operations within the pool. However, the description in section 4. 7 appears to indicate relatively small temperature differences between components in the water pool. Buoyant heat transfer correlations between parallel walls with small temperature differences would indicate convection heat transfer coefficients less than the assumed 600 Wlm2-K value in the SAR. The sensitivity of temperatures (and resulting 13
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-00019 relevant time constraints) for different heat transfer coefficient values was not considered in the SAR's analysis.
- b.
It appears from SAR Table 7.1-1 (step 02.6) that flushing water in the annulus between the canister and transfer cask is necessary for cooling purposes, but a flow rate and supporting calculation were not provided.
This information is needed to determine compliance with 10 CFR 71.35.
Answer:
- a. To confirm the applied heat transfer coefficient for free convection of 600 W/(m2K) for water in the chambers, a comparative calculation based on an appropriate Nusselt law is added at the end of SAR Section 3.6.1.
The sensitivity of transfer cask temperatures to the heat transfer coefficient of water is investigated at the end of SAR Section 3.6.1:
"Regarding the heat transfer coefficients h1 and h2, deviations of +/-30 % only have a minor influence on the calculated temperature difference over the water gaps of +/-1 K."
- b. The flushing water in the annulus between the canister and the transfer cask fulfills no cooling purposes. It is thus not considered within the thermal evaluations.
The flushing with demineralized water ensures that the annulus remains free from radioactive contamination due to inflowing water from the SNF pool. Since the transfer cask is only mentioned as loading relevant equipment and not being part of the transport SAR safety evaluations (but the storage SAR) this is not mentioned explicitly.
No changes to the SAR necessary.
3-9 Clarify that the CASTO~ geo69 package thermal model design and generation, analysis, and review falls under the GNS CASTOR Part 71 quality assurance program.
- a.
Although SAR section 3.3.1.1 mentioned that a particular ANSYS code is verified and validated (e.g., SAR appendix 2-5 to document number 1014-SR-00001 described a verification of the ANSYS finite element program for mechanical calculations), there was no discussion that the thermal modeling design and review process is part of the GNS CASTOR Part 71 quality assurance program. In addition, Staff also notes that although SAR chapter 3 indicates that ANSYS Release 17.2 is used for thermal calculations, SAR appendix 2-5 to document number 1014-SR-00001, which described the verification of the ANSYS finite element program for mechanical calculations, addressed ANSYS 15.0.7 and ANSYS Version 2019 R1; therefore, clarify that the ANSYS version used in the thermal model (Release 17.2) is part of the quality assurance program.
- b.
SAR section 3.3.1.1 stated that the calculation methods for the thermal analyses of several other GNS transport and storage package designs have been validated, including comparison of calculations with experimental results. The validations and experimental result comparisons of the thermal AN SYS models of GNS transport packages should be provided, including discussion regarding their relevance with the GNS CASTOR geo69 transportation package.
This information is needed to determine compliance with 10 CFR 71.35.
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Non-Proprietary Version 25/08/2023 Proprietary Information withheld per -1 OCFR 2.390 to letter T1213-CO-00019 Answer:
Section 1.0 of the SAR Rev. 3 is supplemented by a general statement, that all activities related to the design, fabrication, construction, testing, operation, modification, and decommissioning of structures, systems, and components important to safety of the CASTOR geo69 transport and storage cask are performed under the GNS Quality Assurance Program developed to meet NRC requirements delineated in 10 CFR 71, subpart H, and 10 CFR 72, Subpart G. An associated Quality Assurance Program Description is currently under approval by NRC.
Chapter 3 refers to this passus of Section 1.0.
Furthermore, in Rev. 3 of the SAR, section 3.7 contains three Appendixes regarding validation of computational methods for the thermal design of transport and storage casks and the validation of the ANSYS versions 17.2 and 2020 for thermal calculations.
In SAR Section 3.3.1.1 a discussion about the reason why the results presented in the validation report for various cask and package types are also applicable to the CASTOR geo69 package is added.
3-10 Provide results of thermal energy balances (e.g., numerical residuals), spatial grid generation sensitivity results for steady-state runs, and time step sensitivity results of transient runs for the CASTOR geo69 package ANSYS thermal model.
Although SAR chapter 3 provided normal conditions of transport and hypothetical accident conditions results of the three-dimensional half-symmetric CASTOR geo69 package thermal analyses, there was no discussion that confirmed.grid and time step parameters were appropriate. In addition, there was no discussion that the thermal analyses were appropriately converged.
These numerical parameters help to understand the relevance of the numerical results described in the SAR.
This information is needed to determine compliance with 10 CFR 71.35.
Answer:
New SAR Section 3.3.2.4 about convergence behavior for steady-state calculations and SAR Section 3.4.2.2 about convergence behavior for transient calculations are added to the SAR.
New SAR Section 3.3.3.6 about mesh refinement is added to the SAR.
New SAR Section 3.4.3.2 about time stepping is added to the SAR.
3-11 Clarify and discuss how the increased area of the fins was considered when imposing insolation boundary conditions during normal conditions of transport and for the increased radiation heat transfer during the 30 minute fire hypothetical accident conditions.
SAR section 3.3.1.3 indicates that the package's radial fins were not explicitly modeled; rather, a surface enhancement factor was applied to the heat transfer coefficient at the model's corresponding unfinned surface. However, there was no discussion regarding the increased thermal input to the fin's additional area from insolation during normal conditions of transport and radiation heat transfer from an 800 °C fire.
This information is needed to determine compliance with 10 CFR 71.35.
Answer:
Additional explanations about the surface enlargement of the fins during the fire phase are added at the end of SAR Section 3.3.1.4.
15
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-00019 Additional explanations about the surface enlargement of the fins under insolation are added at the end of SAR Section 3.3.1.4.
3-12 Perform a thermal analysis that assumes cladding failure at normal conditions of transport in order to address the assumption of hypothetical reconfiguration of high burnup spent fuel described in the response to the request for supplemental information RSI 2-6 (ML21245A234).
The response to RSI 2-6 indicated a design approach of including normal conditions of transport and hypothetical accident conditions analyses that assumed hypothetical fuel reconfiguration. Although SAR section 3.5.4 performed a hypothetical accident conditions thermal analysis assuming redistribution of fuel rods, a normal conditions of transport thermal analysis and its results that considered redistribution of fuel rods were not described in the SAR.
This information is needed to determine compliance with 10 CFR 71.35.
Answer:
New SAR Section 3.5.5 with calculations for NCT (hot case) with fuel rod failure and fuel particle release is added to the SAR.
3-13 Provide additional information regarding the 20 detailed model whose temperature results were used to calculate the fuel assembly effective thermal conductivity.
SAR section 3.3 described in broad terms the process of determining the effective thermal conductivity. Additional model information to compare with other models and make a finding include the following: emissivity and absorptivity of the cladding, fuel rod, water rod, fuel channel, the full 20 model wall (basket sheets); basket cell width; dimensions of the components and distances between the listed components in SAR Figure 3.3-4(b).
This information is needed to determine compliance with 10 CFR 71.35.
Answer:
The SAR Section 3.3.1.5 is completely revised supplying additional explanations about the FA modeling and homogenization.
New Figure 3.3-8 with the FE models of all considered FA and new Table 3.3-4 with the applied geometric data are added to the SAR.
For all components, the surface emissivity E is listed in SAR Section 3.2.1. The transmissivity is zero so that the absorptivity amounts to 1 - E. This explanation is added to SAR Section 3.2.1.
3-14 Provide complete thermal analysis discussion of the short-term and operation thermal analyses mentioned in SAR section 3. 6.
The SAR thermal chapter provides thermal analyses of normal conditions of transport and hypothetical accident conditions. However, the two pages of SAR section 3. 6 (Thermal Evaluation for Short Term Operations) only briefly refer to thermal analyses of short-term and operations provided in the docket for the storage cask review (Docket No. 72-1053) which is also under review. However, a complete, standalone application is needed to complete the review. The thermal analyses provided should consider the varied operations discussed in SAR chapter 7, "Package Operations," that could affect thermal performance because of differences in content, package, and transfer positions, canister and cask environments, times for operations to achieve safe conditions, etc.
16
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-00019 This information is needed to determine compliance with 10 CFR 71.31, 10 CFR 71.33, and 10 CFR 71.35.
Answer:
New SAR Section 3.6 about short-term operations is added.
3-15 Provide further details about surface conditions and treatments to achieve the emissivity values listed in SAR Table 3.2. 7.
SAR table 3. 2. 7 listed the emissivity values for different important to safety components.
Further information should be provided that describes the manner that these components rely on surface treatments and the measures in place that ensure an improved thermal performance can be maintained over time.
This information is needed to determine compliance with the regulatory requirements in 10 CFR 71.43(d), 10 CFR 71.51.
Answer:
See also RAI 2-4. In Rev. 3 of the SAR, Sections 2.2 provides the specifications (including the emissivity values) for coatings to be applied to the inner and outer surfaces of the cask body. Chapter 3 takes the values as given with reference to Section 2.2. Provision of surface conditions and treatments is thus not necessary.
4.0 Containment Evaluation 4-1 Demonstrate that the CASTOftJ geo69 transportation system meets the "leaktight" criteria, as described in American National Standards Institute (ANSI) N14.5-2014, "American National Standard for Radioactive Materials-Leakage Tests on Packages for Shipment" by providing for a leakage test of the packaging/canister bodies during fabrication.
Section 4.1.1 of the SAR states: "...that the monolithic cask body and the lids can be considered as leaktight, so the containment analysis can be reduced to the gasket sealing system." Further, in section 4.2.3, the application states that "the design leakage rate of the considered containment is not greater than 10-7 ref-cm3/s (leaktight according to ANSI N14.5)" This application does not clearly indicate that leakage testing of the entire package/canister bodies will be done; however, in order to meet the "leaktight" criteria in ANSI N14.5, the entire containment boundary must undergo fabrication leak testing and meet the leak rate acceptance criteria specified in ANSI N14.5, as there is no recognized standard that allows for the assumption of monolithic materials to be leaktight without being leak tested.
This information is needed to determine compliance with 10 CFR 71.51.
Answer:
It shall be assured that both containment boundaries are entirely free from any defects that could lead to a leakage rate greater than the allowable design-basis leakage rate specified in the confinement analyses.
This is verified in Section 1.0.4 (Table 1.0-2 List of BPVC Alternatives for the CASTOR geo69 Transport Cask) of Rev. 3 of the SAR.
17
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per I OCFR 2.390 to letter T1213-CO-000 19 4-2 Provide the calculation used to determine the leakage rate and potential release from the CASTOR geo69 transportation package, for both normal and accident conditions.
While the NRG does not require leak rate calculations for a package that is tested to leaktight in accordance with ANSI N14. 5, the SAR includes the summary of an analysis to calculate the allowable release rates; however, the actual calculations were not included.
In the SAR, the containment analysis presented is described as having been completed using the "method described in ANSI N14.5". The actual calculations have not been provided as part of the application and the staff needs to review the release calculations in order to confirm that they were done in accordance with ANSI N14.5. Additional guidance on leakage rate testing may be found in section 4.4.2.2 of NUREG 2216.
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Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-00019 This information is required to determine compliance with 10 CFR § 71.51.
Answer:
The calculations are attached at the end of this response (Attachment 1 ).
4-3 Provide the torque specification for the lid bolts of the CASTOR geo69 package lid.
Include this specification in either the operating procedures in the SAR or the drawings for the package. Further, provide a more detailed description of "ultrasonic tightening control" (SAR Page 1. 2-5) and explain how it is used in the tightening of the lid bolts on the CASTOR geo69 package.
The staff was not able to locate a torque specification for the lid bolts of the CASTOR geo69 package in either the SAR or any of the accompanying drawings. The term "ultrasonic tightening control" is not one that is familiar to the staff in context of its use in section 1. 2. 1. 2 of the SAR. Further clarification of this term is requested.
This information is required to determine compliance with 10 CFR §71.51.
Answer:
In Rev. 3 of the SAR, section 1.2.1.2 the term "ultrasonic tightening control" is refined.
It means "ultrasonic-based and preload assisted tightening" of screws. Thereby the preload applied to the screw changes its length and can thus be determined live by measuring the runtime of the ultrasound through the screw. Instead of specifying a torque for the cask lid screws, the preload is to be specified consistently to the one used within the structural evaluations. E.g. in Tab. A 165 in 1014-TR-00024 the preloads to be applied for the cask lid bolting depending on the temperature are calculated. For a temperature of approx. 20°C a preload range between is determined to be applied. The nominal preload used in the proof of sufficient lid gasket compression; Canister Lid The same is for the trunnion bolts (see 1014-TR-00026). All other screw connections are tightened with torque support 4-4 Provide a table in the application to summarize all leakage rate tests performed on the CASTOR* geo69 package and clarify (in the table) whether ANSI N14.5 or another standard, is used in the leakage rate tests.
- a.
The applicant described the leakage rate tests in SAR Sections 4.4, 7.1.2 and 8.2.2. The applicant should provide a table in SAR chapter 7 or chapter 8 to summarize the fabrication, pre-shipment, maintenance, and periodic leakage rate tests. Information provided in the table should include, but not be limited to, leakage test criteria, test sensitivity, test methods, test frequency, and containment components that are subject to testing for each of the fabrication, pre-shipment, maintenance, and periodic leakage rate tests.
- b.
Clarify whether ANSI N14.5 (a consensus standard), or another standard, is used in the leakage rate tests. If ANSI N14. 5 is used, clarify whether the leakage rate testing procedures are approved by personnel whose qualifications and certifications in the non-destructive method of leak testing include certification by a nationally recognized society at a level appropriate to the writing and/or review of leakage rate testing procedures (e.g., an American Society of Non-destructive Testing (ASNT) Level Ill in leak testing) as noted in section 8. 8, "Quality Assurance," of ANSI N14. 5, or equivalent. An ASNT Level Ill in leak testing can be of great value in the design of a high reliability, economical leak 19
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 testing program that includes selection of methods, equipment, and generation of procedures.
This information is needed to determine compliance with 10 CFR 71.51.
Answer:
Subsections 8.1.4 and 8.2.2 are supplemented with further details on leakage testing.
Tables 8.1.4, 8.1-5 and 8.1-6 as well as Table 8.2-1 summarize the fabrication, pre-shipment, maintenance, and periodic leakage rate tests. Leakage test criteria, test sensitivity, test methods, etc. are also mentioned. For all containment components the test criterion is defined by GNS as 1 o-s Pa m3/s with a required detector sensitivity of 10-10 Pa m3/s. LT is performed by usage of the methods of ANSI N14.5 by personnel qualified acc. to the requirements of SNT-TC-1A. LT procedures shall be approved by personnel whose qualification and certification in the NOT method of LT includes certification by a nationally recognized society at a level appropriate to the writing and/or review of LT procedures (e.g. Level Ill by American Society for Non-destructive Testing or equivalent).
5.0 Shielding Evaluation 5.1 Clarify the SAR to consistently identify the materials used in the casing of impact limiters.
See items 1-1 and 2-11, above.
The applicant states in the SAR that The impact limiters protect the casks during transportation and is made of steel casing filled with polyurethane foam." The drawings show an aluminum casing.
The staff needs this information to determine compliance with the requirements of 10 CFR 71.47, and 10 CFR 71.51.
Answer:
Section 5.1.1 erroneously states that "... both impact limiters include steel as housing and inner lying structure sheets... ", although the real construction envisage aluminum casing. Since it is also stated further in text that the polyurethane foam casing is conservatively not modelled in the shielding analysis as the impact limiters do not bear a dedicated shielding function, the wrongly designated material has no influence on the shielding analysis. The mistakenly designated material (steel) will be named properly (aluminium).
The text in Section 1.1 will also be corrected accordingly.
5-2 Provide justification that. the 3 percent fuel failure rate in normal conditions of transportation is adequate for high burnup spent fuel or spent fuel that has been in storage for longer than 20 years.
The SAR state: "CASTO~ geo69 will transport high burnup spent fuel, therefore, the impact of the 3 percent fuel failure under NCT [normal conditions of transport] is evaluated according to: [1] the source occurring due to fuel failure is relocated to the bottom and to the top regions of the canister; the regions with potentially lower shielding performance due to flattenings in the trunnion regions; and due to finite axial size of the moderator rods."
The 3% fuel reconfiguration assumes that the fuel is loaded as intact fuel. In response to staff RSls (ML21245A234), the applicant stated that they are not crediting the cladding for high burnup fuel, therefore no credit is taken for cladding as the primary barrier to radioactive materials releases. If no credit taken for cladding in shielding, 20
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-00019 therefore, the shielding analyses for high burnup fuel must consider all possible fuel relocation, packing factor, vertical position, horizontal position, redistribution of source terms under transportation of the package. Justify that the 3 percent fuel failure during normal conditions of transport is acceptable since the CASTOR geo69 does not take credit for cladding.
The staff needs this information to determine if the CASTO~ geo69 system design meets the regulatory requirements of 10 CFR 71.47.[1] NUREG-2224, Dry Storage and Transportation of High Burnup Spent Fuel, Washington, DC, November 2020.
Answer:
We cannot quite comprehend your statement that the cladding for high burn-up fuel is not credited. The cladding is credited in the shielding analysis. Since the fuel eligible for a loading has to be undamaged, the shielding function of the cladding is retained. Under NCT, it is assumed that 3% of the fuel rods fail. The rubbleised mixture of fuel and cladding (packing factor 0.58) is relocated (see Section 5.3.1). The rubble is positioned in the regions with minimum shielding, namely in front of the flattenings (minimum wall thickness, see Figure 5.3-2). The remaining 97% of the fuel rods remain in their original configuration and contribute to the dose rate with a strength of 97%.
Therefore, no changes to the SAR have been implemented based on this comment.
5-3 Provide explanation how positions are identified in the loading schematic of the package.
It states in SAR "Figure 1.2-8 shows the general loading schematic of the cask viewed from the top, including basket position numbers 1 to 69 and position groups A to F.
Position groups are defined by positions which are treated equivalently in terms of shielding and decay heat limit."
Explain what is meant by "are treated equivalently in terms of shielding and decay heat limit," at the bottom of page 1. 2-22.
The staff needs this information to determine compliance with the requirements of 10 CFR 71.47, and 10 CFR 71.51.
Answer:
The position groups are chosen such that the heat dissipation paths for the fuel assemblies within a particular group as well as the contribution of the fuel assemblies within a particular group to the external dose rate are similar. In other words, the fuel assemblies expected to contribute similarly in terms of their decay heat dissipation and the dose rate outside the cask are grouped together.
Within one group, all fuel assemblies are treated identically as if they all would have a maximum admissible decay heat according to the corresponding thermal requirement and the maximum admissible radiation source term strengths.
We admit we have selected a very unfortunate formulation for this simple statement. We will substitute "which are treated equivalently in terms of shielding and decay heat limit,"
with "which are expected to contribute similarly in terms of their decay heat dissipation and the dose rate outside the cask and are treated identically with their corresponding maximum admissible decay heat (see Figure 1.2-9) and maximum admissible radiation source term strengths (see Section 5.2)".
Revision of the SAR.
5-4 Explain clearly how the tolerance evaluated for nominal thickness of the package.
21
[\Jon-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 In the SAR, section 5. 1. 1, stated that; "The thicknesses of the materials relevant for the shielding analysis are set to their minimum. For example, the nominal thickness of the cask is 370 mm, the shielding model assumes Cleary explain how the tot transferred to cavity diameter and why this approach acceptable to use.
The staff needs this information to determine compliance with the requirements of 10 CFR 71.47, and 10 CFR 71.51.
Answer:
The outer diameter of the cask and the cavity diameter are tolerated according to Figure 5.1-3. In order to determine the minimum wall thickness, the maximum cavity diameter has been subtracted from the minimum outer cask diameter The missing compared to the nominal wall thickness of are deliberately taken away thus attributing the deviation Provided the results include two standard deviations from penalizing error propagation (see Section 5.4.4), this approach is acceptable.
An explanatory statement is added to the SAR.
5-5 Clarify nominal or reduced dimension used in evaluation the dose rates.
It states in the SAR that: "The dose rates on the face sides of the package are much smaller than on the shell side, which is decisive for the design, therefore, the This statement seems to contradict with other parts of the SAR where dimensions are decreased in the shielding model (see above section 5.1.1 which states that dimensions are reduced in the modeling).
The staff needs this information to determine compliance with the requirements of 10 CFR 71.47, and 10 CFR 71.51.
Answer:
No tolerance has been applied to the thickness of the cask bottom, neither has it been taken into account for the components of the cask lid. Due to the overall thicknesses of the materials on both face sides of the package and far below the 10CFR71.47 limits (see Table 5.1-1 ). For this reason, the thicknesses of the face ends of the package For each component on the shell side (radially outwards), the tolerances have been taken into account in a way to *reduce the thicknesses of the materials and to increase the calculated dose rates.
An explanatory statement is added to the SAR.
5-6 Clearly explain the "other" conservative assumptions (see underline below) that were made. In addition, provide a more thorough explanation of how length growth affects the shielding performance.
It states in the SAR: "Possible negative img_act of the bigger lid side central opening on the dose rates of the lid side of the cask should be more than compensated by other conservative assumQtions made. Firstly, the plating of the 22
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 0CFR 2.390 to letter T1213-CO-00019 polyurethane foam is not considered in the shielding model at all; its presence would provide a better shielding. And secondly, the length growth would not only provide more material but also shift the normally occupied space further from the cask."
It is not clear what the possible negative impact on shielding is referring to, and what are the other conservative assumptions were made to justify compensate the dose rates, and what is the length growth and how it effects the dose rates.
The staff needs this information to determine compliance with the requirements of 10 CFR 71.47, and 10 CFR 71.51.
Answer:
What concerns the bottom-side impact limiter, all the changes made will have a positive effect on the shielding performance of the package, since more material is designed compared to actual shielding model described in the SAR.
The changes made to the lid-side impact limiter include among others a wider central opening (+10 mm compared to the previous design, which is replicated in the shielding model). This wider opening should have a negative impact (most probably marginal and not even worth discussing) on the dose rate on the lid side of the package. Anyway, there are different aspects of the impact limiter construction itself as well as of the shielding model that would allow to fully mitigate this negative impact.
Firstly, the overall length of the lid-side impact limiter has become greater compared to the actual shielding model. This design change does provide more material and (which is probably more important) shifts the loci relevant for the dose rate registration away from the package. E.g. the position of the vehicle driver would be further apart from the radiating source.
Secondly, the housing of the polyurethane foam (aluminum), which has a significantly higher density compared to the foam itself, has not been modelled. Thus, the conservative assumptions, mainly assuming shorter distances from the package surface and neglecting the housing completely, are sufficient to compensate the negative effect of making the central opening bigger.
The text in the SAR will be adjusted accordingly to clarify the description. A comparative calculation with actual dimensions of the impact limiters will be performed, and its results will be documented.
6.0 Criticality Evaluation Note by GNS: Regarding SAR.Rev. 3, Subsection 6.3.6.4 (Round Edges of Basket Sheets)
Due to a small change in the constructive design of the fuel basket - variable height of the Al-84C-MMC basket sheets (
, and sensitivity analysis regarding the missing Al-84C-MMC material (missing boron content) have been performed confirming that the presence of the round edges of the basket sheets does not lead to any increase in reactivity.
6-1 Clarify the distribution of the empty basket positions in the partial loading evaluations.
The applicant evaluated a series of single, empty basket locations as well as different numbers of multiple empty locations. In section 6.3. 6. 1 of the application, the applicant describes the single empty locations as "radially distributed" and shows the location identifiers in Figure 6.3-10 of the application. The applicant then states the results are given in table 6. 3-5 and Figure 6. 3-11; however, these numbers do not correspond to 23
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-00019 the basket location identifiers shown in the figure described in the previous sentence. It seems these numbers relate to a separate evaluation of multiple empty positions, but it is not clear from the applicant's description. There are also no description or figures showing the distribution of multiple empty basket positions.
This information is required to determine compliance with 10 CFR 71.55(b).
Answer:
It is our understanding that this question refers to SAR 1014-SR-00001 Rev. 0. This issue was already fixed in Rev. 1 of the SAR. In Table 6.3.5 the numbers of the empty basket positions had been corrected.
7.0 Operating Procedures 7 -1 Provide general guidance in the operating procedures for controlling the radiation level limits on unloading operations and procedures for addressing situations when surface contamination and radiation surveys are too high.
Steps H1 and H2 insection 7.1.3 of the operating procedures requires verification of the contamination levels and dose rates prior to shipment. However, there are no procedures associated with controlling radiation level limits and addressing situations when contamination and radiation levels exceed regulatory limits. Section 8.4.2.1, "Receipt of Package from Carrier," in NUREG-2216, "Standard Review Plan for Transportation Packages for Spent Fuel and Radioactive Material," states that the staff should ensure that the package operating procedures include actions to be taken if contamination or radiation levels exceed those listed in 10 CFR Part 71. The NRG notes that it occasionally receives notifications from its licensees that, after package receipt at its destination, measurements of contamination or radiation levels have exceeded the requirements in 10 CFR 71.87(i) or 10 CFR 71.47, respectively, even though contamination and dose rate measurements prior to shipment did not exceed the requirements.
Regulatory Guide 7. 7, "Administrative Guide for Verifying Compliance with Packaging Requirements for Shipping and Receiving of Radioactive Material" section 4. 0, "Receiving and Opening a Package," contains an approach that the staff considers acceptable for meeting the requirements associated with receipt of radioactive material in 10 CFR Part 71 and 10 CFR Part 20. In addition, NUREGICR-4775, "Guide for Preparing Operating Procedures for Shipping Packages," may contain useful information.
This information is needed for a user to be able to comply with 10 CFR 71.89 and 10 CFR 20.1906.
Answer:
Chapter 7 of the SAR has been supplemented by a Subsection 7.0.2 "Excessive Radiation or Contamination Levels" providing the procedures demanded by NUREG-2216 Subsection 8.4.2.1 in accordance with the guidelines of RG 7.7 and NUREG/CR-4775. This Subsection 7.0.2 is referenced in the respective work steps in Sections 7.1 through 7.4.
7-2 Either revise the operating procedures to include the package pre-shipment leakage rate tests and criterion in tables 7.1-2 and 7.1-3 "Operations for preparation for transport," or the NRC will make the criterion for the leak rate tests a condition of the certificate of compliance.
24
Non-Proprietary Version 2510812023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-000 19 In section 4. 1. 1 of the SAR, the applicant indicates that for both the "inner and "outer
containment, a maximum reference air leakage rate of 1 x 10-7 ref cm3/s (leak test criterion) is demonstrated by a leakage test after loading (see SAR chapter 7, table 7.1-
- 2) and that "this maximum reference air leakage rate is proven" for the outer containment prior to transport; however, a "pre-shipment" leakage test is not listed as a step in the procedures listed in table 7.1-3, "Operations for preparation for transport." In addition, the acceptance criterion for the test in section 7. 1.2 is not provided.
This information is needed to determine compliance with 10 CFR 71.51.
Answer:
In Table 7.1 2 "Operations for loading of contents" leakage tests are required for both, the canister lid system (Step F11) as well as the cask lid system (Step G14). The requested test criterion of 1
- 10-a Pa* m3ls has been added.
The leakage test criterion is defined by GNS in Section 8.1 (consistent to Section 4.1) and represents the maximum standard helium leakage rate. The leakage tests are to be performed according to the methods of ANSI N 14.5.
7 -3 Either ensure that the tilting studs are rendered inoperable for lifting and tying down the package or evaluate the titling studs for compliance with the requirements for lifting and tie-downs.
While the tilting studs are not designed to be a lifting attachment or for tying down the package, they are a structural component of the package that could be used to lift or tie down the package. It is not clear from the application whether the tilting studs are accessible for use as tie-downs or lifting during transport or removed from the package.
This information is needed to determine compliance with 10 CFR 71.45(a).
Answer:
As can be seen from the transport configuration drawing 1014-DD-44719 111 Rev. 0 (Appendix 1-3 of the SAR) the tilting studs are rendered inoperable for lifting and tying down the package during transport since they are completely covered by the impact limiters. To make this clear in the text, a corresponding passage is inserted in Section 1.2.1.1.
7-4 Revise section 7.2.2.2, "Removal of Contents via CLU," Step Min table 7.2-3 which provides the operational steps describe for lowering the canister into the pool water and reflooding of the canister cavity with pool water to provide criteria to control the temperature differential between the fuel rod and the pool water to ensure that fuel damage does not occur. Ensure that the application contains sufficient justification for the criteria.
Canister reflooding prior to removing the spent fuel should ensure that the temperature differential would not exceed that which would cause significant change in the thermal response of the fuel cladding to cause degradation and cladding failure prior to unloading the fuel to ensure that doses to a licensee unloading the package meets the dose rates and the as low as is reasonably achievable (ALARA) principal in 10 CFR Part 20, "Standards for Protection Against Radiation." Note that this should include, as appropriate, material degradation due to aging and irradiation.
The information is needed to determine compliance with 10 CFR 20. 1101 and 10 CFR 20.1201, 10 CFR 71.55 and 10 CFR 71.89.
Answer:
25
f\lon-Proprietary Version 2510812023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 Chapter 7 of the SAR has been supplemented by a Subsection 7.2.2.1 "Re-Cooling of SNF Prior to Underwater Cask Unloading" providing the principle procedure for re-cooling SNF prior to under water unloading of FA from the CASTOR geo69 cask. The procedure outlined excludes with certainty a thermal shock of the fuel rods and thus a failure of the fuel rod cladding as a result of the contact of fuel pool water with the hot fuel rods.
8.0 Acceptance Tests and Maintenance Program 8-1 Provide additional information on the qualification testing or acceptance testing of the fuel basket plates that demonstrates adequate uniformity of the boron carbide distribution to support subcriticality.
SAR appendix 2-8, "Material Qualification,
" states that neutron transmission tests are preferred, but not required, to demonstrate uniform boron distribution in the acceptance testing of the fuel basket plates. The "non-preferred" alternative is a combustion chemical analysis with additional metallographic examinations. The SAR does not provide acceptance criteria for the metallographic examinations to verify adequate boron uniformity.
The guidance in NUREG-2216, section 7A.1.5, states that methods other than neutron attenuation testing (such as chemical analysis) can be used for acceptance testing, provided that the alternative method has been previously qualified and benchmarked with direct attenuation measurements. In that guidance, applicants are encouraged to provide statistically significant data showing the correspondence between neutron attenuation testing and the alternative testing.
The staff requests the following information to demonstrate how the chemical analysis and metallographic examinations can be used to adequately characterize the boron uniformity in the acceptance testing of the manufactured plates:
- 1. Provide available data that benchmarks the combustion chemical analysis and metallographic testing with neutron attenuation measurements
- 2. Provide the acceptance criteria (and a justified basis) for the metallographic examinations for boron uniformity.
This information is needed to demonstrate compliance with 10 CFR 71.33(a)(5), and 71.55(b), (d) and (e).
Answer:
The qualification report for the ***** material (1014-TR-00011 Rev. 3, Appendix 2-8 in Chapter 2.12 of the SAR) is supplemented with an assessment regarding the homogeneity of the boron distribution within the AL-B4C-MMC bulk. The homogeneity of the qualification profile is demonstrated by both, direct and indirect methods. Grinding patterns at different positions across the profile and in different directions are shown. The 10B areal density as a measure for the homogeneity of the boron distribution is determined directly by neutron transmission measurement as well as indirectly by a chemical analysis including a measurement of the 10B/11 B ratio and under consideration that the mechanical properties are according to the specifications.
The results of both methods presented are comparable demonstrating the they are both suitable as a prove of the homogeneity of the boron distribution during batch production.
8-2 Provide a frequency for replacement of the elastomeric and metallic seals for the CASTOR geo69 package lid.
26
!\Ion-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-00019 SAR section 8.2.2 indicates that elastomeric sealing rings and metallic gaskets are inspected and "may be replaced" in the course of leakage testing of the package. There does not appear to be a specific frequency or schedule provided for replacement of these seals. Section 9.4.2.2, "Leakage tests," of NUREG-2216 provides NRC guidance on seal replacement frequency.
This information is required to determine compliance with 10 CFR 71.51.
Answer:
Both, Sections 8.1 and 8.2 are added with information regarding a replacement schedule for metal gaskets and elastomeric seals. Furthermore, Section 8.2 of the SAR Rev. 3 is supplemented by a Subsection 8.2. 7 tabulating periodic test and replacement schedules for package components during loading, prior to transport and/or during maintenance operations.
9.0 Quality Assurance The following questions are on the quality assurance program submitted on July 10, 2020 (ML20198M431).
9-1 Revise section 10.4.3-1 to provide additional information on the design measures or specific method captured in your Quality Assurance Manual (QAM) II to select and review for suitability of materials, parts, and equipment that are important to safety such as standard or commercial (off-the-shelf) material, parts, and equipment.
GNS-Quality Assurance Program Description (QAPO) chapter 3.3 states, in part, that the design methods, as well as applicable materials, parts, computer codes, equipment and processes that are essential to the functions of the components and systems being designed are specified in the QAM II. Provide a brief description of the design measures specified in the QAM II to select and review for suitability of application of materials, parts, equipment, and process that are important to safety.
This information is needed to demonstrate compliance with 10 CFR 71.107.
Answer:
QAPD, Chapter 3.3 (Design Process), has been supplemented:
"Written procedures are established to identify and control the authority and responsibilities of all individuals or groups responsible for design reviews and other design verification activities."
"For the selection of suitable materials, parts, equipment, and processes for SSCs important to safety valid industry standards and specifications are used.
In parallel to the above mentioned design process the qualification and/or identification of the applicable supply chain (e. g. NQA-1 qualified supplier, CGDI, QAPS) on basis of the graded approach chosen is taking part."
Reference to 10 CFR 71.107 was given in chapter 3.9 (Regulatory Commitment).
9-2 Revise section 10.4.7-1 to provide additional information on how GNS plans to implement the control of commercial-grade items and services.
GNS-QAPD Chapter 7. 7 states, in part, that when commercial-grade items and services need to be procured, the control of such purchased items and services shall "be" performed as described in the QAM II. Added the "be" to the sentence for editorial and verbiage consideration. Provide a brief description on how GNS plans to implement the control of commercial-grade items and services.
27
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-CO-000 19 This information is needed to demonstrate compliance with 10 CFR 71.115.
Answer:
QAPD, Chapter 7.7 (Commercial Grade Items and Services) has been extensively supplemented.
"In the QAP Procedures are established to be able to perform under Commercial grade requirements for items and services.
The dedication is an acceptance process to provide reasonable assurance that a commercial grade item or service will successfully perform its intended safety function and, in this respect, is deemed equivalent to an item or service provided under the requirements of NQA-1. This assurance is achieved by identifying the appropriate critical characteristics of the item or service and verifying their acceptability.
The basis of the dedication (Commercial Grade Dedication - CGD) is a technical evaluation which includes:
- Identification of Item or service for procurement as a Commercial Grade and determine if the item or service is eligible for Commercial-Grade Dedication
- Determination of safety functions and performance requirements of the item /
service
- Identification of critical characteristics and acceptance criteria
- Definition of dedication methods
- Special Tests, Inspections, or Analyses Commercial Grade Survey
- Source Verification
- Acceptable Performance Record.
Dedication plans may be developed for a specific item, service, or for a generic group of items or services. Dedication requirements shall be included in applicable procurement and technical documents as necessary to support the dedication.
The documentation of the commercial grade dedication process shall be traceable to the items or services and shall include the following documents, depending on the applicable dedication methods:
- 2. Technical evaluation
- 3. Dedication plan
- 4. Test, inspection or analysis reports including results
- 5. Commercial Grade Survey reports
- 6. Source verification reports
- 7. Performance records.
The equivalence of the methods chosen to the requirements of NQA-1 shall be confirmed."
Reference to 1 0 CFR 71.115 was given in chapter 7.10 (Regulatory Commitment).
9-3 Revise section 10.4. 12-1 to provide additional information on the GNS process for using subcontractors for calibration services.
28
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 GNS-QAPD Chapter 12.3 states, in part, that calibration may be subcontracted to approved suppliers on the Approved Suppliers List. Does GNS plan to use accredited laboratories in lieu of performing a vendor evaluation (survey) to satisfy calibration testing requirements? The NRG staff provided a few restrictions when using laboratory accreditation by Accreditation _Bodies that are signatories to the International Laboratory Accreditation Cooperation (/LAC) Mutual Recognition Arrangement (MRA) in lieu of performing commercial-grade surveys as part of the commercial-grade dedication process for procurement of calibration and testing services.
This information is needed to demonstrate compliance with 10 CFR 71. 115 and 10 CFR 71.125.
Answer:
QAPD, chapter 12.1 (Control of Measuring and Test Equipment; General) has been supplemented:
"GNS uses accredited calibration services and laboratories in accordance to ISO/IEC 17025, !LAC or MRA."
Reference to 10 CFR 71.125 and was given in chapter 12.5 (Regulatory Commitment).
9-4 Revise section 10.4.17-1 to provide additional information to describe how GNS comply with the record retention requirements.
GNS-QAPD Chapter 17.5 states, in part, that all records shall be maintained for their retention periods according to the QAM II. Provide a brief description of the record retention requirements (i.e.,
- duration, location, fire protection, and assigned responsibilities) as provided in your QAM II.
This information is needed to demonstrate compliance with 10 CFR 71. 135.
Answer:
QAPD, chapter 17.5 (Receipt, storage, retention, and maintenance of records) and chapter 17.6 (Maintenance of records) have been summarized and extensively supplemented.
"Each organization is responsible for organizing and implementing receipt controls for temporary and permanent storage.
Records received from suppliers shall be reviewed for completeness, correctness, and legibility.
In case customer, jurisdictional, or regulatory requirements define a different record retention period than described within the QAP, such deviated retention periods shall be described in the Quality Project Manual.
GNS retains these records for at least 3 years beyond the date when the licensee, certificate holder, and applicant for a Certificate of Compliance last engage in the activity for which the quality assurance program was developed. If any portion of the Quality Assurance Program, written procedures or instructions is superseded, GNS shall retain the superseded documents for 3 years after it is superseded.
29
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 Table 17-1: Quality Assurance records - classification and retention time Quality Assurance Record L TINP QAM NP 3 QAM-P ASL ITP List of Technical Requirements and Boundary Conditions LAD Design Specification incl. attachments Design Report incl. attachments Safety Report incl. attachments Computer Program Verification/Validation Fabrication Specification incl. attachments Test Specification/Work Instruction PSL Procurement Requisition Request for Quotation Quotation (with followed PO)
Purchase Order Supplier document Fabrication documentation (Supplier documentation) incl. FTP, NCR Manufacturing documentation (GNS) incl. FTP, NCR Audit/Survey Report CAR Calibration Record Personal qualification record LT = Lifetime Record; NP = Nonpermanent Record [years]
NP 3 NP10 NP10 NP10 NP10 NP 10 LT LT LT LT LT LT NP 6 NP 10 NP 6 NP 6 LT LT LT LT NP 3 Until recalibrated NP 3 Records are maintained and protected from degradation, damage or loss by the following measures:
restricted access permanent preservation by regulation of climate, air and light to prevent damage from mold, pollutants or sunlight structural and technical measures to protect against fire and water damage.
GNS' record storage facilities (archive) are constructed, located, and secured to prevent destruction of the records by fire, flood, theft, and deterioration by environmental conditions (such as temperature or humidity). The facilities are maintained by, or under the control of, GNS throughout the life of the transport package, DSS or the individual product.
Filed records can be retrieved from storage or GNS databases by qualified personnel in a controlled manner.
30
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 An unacceptable deterioration of the electronic recoding media which could occur during the specified retention period is ensured by the use of PDF/A file format and redundant storage or separate archiving of data or appropriate data backup."
Reference to 10 CFR 71.135 was given in chapter 17.6 (Regulatory Commitment).
9-5 Revise section 10.4.17-2 to provide additional information on how GNS minimize the risk of loss, damage, or destruction to quality records or how GNS provide provisions for electronic storage.
This information is needed to demonstrate compliance with 10 CFR 71.135.
Answer:
QAPD, chapter 17.5 (Receipt, storage, retention, and maintenance of records) and chapter 17.6 (Maintenance of records) have been summarized and extensively supplemented.
New text see answer to 9-4.
Reference to 10 CFR 71.135 was given in chapter 17.6 (Regulatory Commitment).
9-6 Revise section 10.4. 18-1 to provide additional information to describe measures to analyze and trend audit deficiency data as well as ensure that the resulting reports, indicating quality trends and the effectiveness of the quality assurance program, are given to management for review, assessment, corrective action, and follow up.
GNS-QAPD Chapter 18. 6 states, in part, that the individual responsible for the organization or activity audited shall investigate audit findings, establish corrective actions, including measures to prevent recurrence, and notify the Lead Auditor of Corrective Action taken or planned. The Lead Auditor shall evaluate the proposed measures in respect of effectiveness, suitability, and implementation of corrective action. Please clarify what is meant by effectiveness, suitability, and implementation to equate to measures for analyzing and trending audit results and management reviews of audit findings.
This information is needed to demonstrate compliance with 10 CFR 71.137.
Answer:
QAPD, chapter 18.6 (Audits; Response) has been supplemented:
"Corrective action should ensure that auditing organizations schedule and conduct appropriate follow up to ensure that the corrective action is effectively accomplished."
QAPD, chapter 18.7 (Audits; Follow-up Actions) has been supplemented:
"The Lead Auditor shall evaluate the proposed measures in respect of effectiveness, suitability, and implementation of corrective action using audit nonconformance reports within the following work-flow as determined:
Identification of the nonconformity Cause analysis Corrective action to be done check of documentation concerning corrective action taken evaluation of effectiveness of measures/ no recurrence confirmation of completion of correc_tive action.
Reference to 10 CFR 71.137 was given in chapter 18.9 (Regulatory Commitment).
31
Non-Proprietary Version 2510812023 Proprietary Information withheld per 1 OCFR 2.3~ to letter T1213-CO-00019 G NS ATTACHMENT 1 acc. to Item 4-2 (Chapter 4 Containment Evaluation)
Figure 1 in ANSI N14.5 [1] shows a flow chart how to use the Standard. After determining the Allowable Release Rates - RN and RA for NGT and HAG, resp. (Section 5 in [1]) the Allowable Leakage Rates - LN and LA (Section 6 in [1]) and the Reference Air Leakage Rate -
LR (Section 6 in [1]) are calculated.
Requirements according to Section 5 in [11 to determine the Allowable Release Rates RN and R6 for NGT and HAG:
Step 1: Identify the radioactive contents.
This requirement is fulfilled in Appendix 4-1 of the SAR and is supplemented by Section 4.2.3 for NGT and Section 4.3.3 for HAG.
Step 2: Determine the total releasable activity.
Based on references to previous demonstrations compiled in NUREG-2224 [21, the release fractions of gases, volatiles, fines and crud are given in Appendix 4-2 of the SAR together with the assignment of nuclides to these chemico-physical forms. This requirement is fulfilled in Section 4.2.3 for NGT and Section 4.3.3 for HAG. For NGT the sum of mobilized activity yields (cf. Section 4.2.3). For HAG the sum of mobilized activity yields ***lfor HAG-fire conditions and ***I for HAG-impact conditions (cf. Section 4.3.3).
Step 3: Determine an A2 value for the releasable activity.
Based on the nuclide-specific A2 values (cf. Section 4.2.2 and Section 4.3.2), this requirement is fulfilled in Section 4.2.3 for NGT and Section 4.3.3 for HAG. For NGT the A2 value for the mixture yields ***
(cf. Section 4.2.3). For HAG the A2 value for the mixture yields for HAG-fire conditions and **for HAG-impact conditions (cf. Section 4.3.3).
Step 4:Determine the release rate limit for normal conditions of transport, RN, and for hypothetical accident conditions, RA.
The Allowable Release Rate RN for NGT is calculated in Section 4.2.3 of the SAR as RN = 10-5. A2lhr = 10-e.
The Allowable Release Rates RA for HAG are calculated in Section 4.3.3 of the SAR as RA = A2lweek =
RA= A2lweek =
for HAG-fire and for HAG-impact.
Requirements according to Section 6 in [11 to determine the Allowable Leakage Rates LN and LA for NGT and HAG:
Section 6. 1, Equation 3 For NCT the sum of mobilized activity concentration CN is determined as 18 TBqlm3 for the content (cf. Section 4.2.3).
The Allowable Leakage Rate LN for NGT is calculated in Section 4.2.3 of the SAR as LN = RN I GN =
with RN according to Section 5, step 4 in [11 (see above).
32
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 Section 6. 1, Equation 4 For HAC the sum of mobilized activity concentration CA is determined CA as HAC-fire conditions and for HAG-impact conditions (cf. Section 4.3.3).
The Allowable Leakage Rates LA for HAC are calculated in Section 4.3.3 of the SAR as LA= RA/ CA=
LA= RA/ CA=
for HAC-fire and for HAC-impact with RA according to Section 5, step 4 in [1] (see above).
for Requirements according to Section 6 in [1] to determine the Reference Air Leakage Rate LR:
Step 1: Determine LN (Equation 3).
The Allowable Leakage Rate LN for NCT is calculated in Section 4.2.3 of the SAR (see above).
Step 2: Determine LA (Equation 4).
The Allowable Leakage Rates LA for HAC are calculated in Section 4.3.3 of the SAR (see above).
Step 3:Determine the air leakage rate at standard conditions that is equivalent to LN. For this determination, which represents normal conditions of transport, the leakage should be assumed to occur under normal operating conditions that result in the greatest leakage rate.
The maximum allowable leakage hole diameter for which the allowable leakage rate LN results is calculated by solving the Knudsen equation and using Newton's method. The Knudsen equation with Pa= (Pu +pd)/ 2 provides consistent results for the listed parameters from table 4.2-6 of the SAR when the capillary diameter D is set to D =
The leakage hole diameter Dis used to convert LN to an air leakage rate at standard conditions, i.e. dry air leaking from Pu = 1 atm to Pd= 0.01 atm at a temperature of-again by solving the Knudsen equation with the parameters for standard conditions from table 4.2-7 of the SAR.
33
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 The units for the parameters Pu, Pd, M and µ(T) are converted according to the expected units of the Knudsen equation as follows:
This gives:
= LR,N.
Pu= 1.0 atm
- 1.013E05 Pa/atm = 1.013E05 Pa, Pd= 0.01 atm
- 1.013E05 Pa/atm = 1.013E03 Pa, Pa= (Pu +pd) I 2 = (1.013E05 Pa+ 1.013E03 Pa)/ 2 = 5.12E04 Pa, M=
µ(T) =
Note that this entity is designated as LR in the SAR. Here, it is denoted as LR,N (cf. Example 19 in Section 8.15.19 of [11) to clarify that it is the applicable reference leakage rate for NCT.
Step 4:Determine the air leakage rate at standard conditions that is equivalent to LA. For this determination, which represents hypothetical accident conditions, the leakage should be assumed to occur under hypothetical accident conditions that result in the greatest leakage rate.
The maximum allowable leakage hole diameter for which the allowable leakage rate LA results is calculated by solving the Knudsen equation and using Newton's method. Here, we display the calculations exemplarily for HAC-fire. The.Knudsen equation with Pa = (Pu +pd)/ 2 provides consistent results for the listed parameters from table 4.3-11 of the SAR when the capillary diameter D is set to D =
34
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letter T1213-GO-00019 The leakage hole diameter D is used to convert LN to an air leakage rate at standard conditions, i.e. dry air leaking from Pu= 1 atm to pd= 0.01 atm at a temperature of-again by solving the Knudsen equation with the parameters for standard conditions from table 4.3-12 of the SAR. The units for the parameters Pu, Pd, M and µ(T) are converted according to the expected units of the Knudsen equation as follows:
Pu= 1.0 atm
- 1.013E05 Pa/atm= 1.013E05 Pa, pd= 0.01 atm
- 1.013E05 Pa/atm = 1.013E03 Pa, Pa = (Pu +pd) / 2 = (1.013E05 Pa + 1.013E03 Pa}/ 2 = 5.12E04 Pa, M=
µ(T) =
This gives:
L(p) = -*-*(p -p )+ -*
- -*(p -p) *-
(
TT D
4 1 p¥TT*R*T D3
) Pa u
128 µ*a u
d 6
M a*pa u
d Pu Note that this entity is designated as LR in the SAR. Here, it is denoted as LR.A (cf. Example 19 in Section B.15.19 of [1]) to clarify that it is the applicable reference leakage rate for accident conditions, in this case HAC-fire.
In the same way reference air leakage rates for HAC-impact I and HAG-impact 11 with parameters from table 4.3-11 of the SAR are performed leading to values of (HAG-impact I) and----- (HAG-impact I) displayed in table 4.3-12 of the SAR.
Step 5: LR is the more restrictive of the values LN or LA as determined in Steps 3 and 4, above.
The overall reference air leakage rate LR is determined as ******
It is the value as determined in Step 3 for NCT. With the stipulations for leakage rate tests in section 4.4 of the SAR, it is ensured that the leakage of the CASTOR geo69 is lower than LR.
35
Non-Proprietary Version 25/08/2023 Proprietary Information withheld per 1 OCFR 2.390 to letterT1213-CO-00019 References
[1]
ANSI N14.5-2022, American National Standard For Radioactive Materials - Leakage Tests on Packages for Shipment
[2]
NUREG-2224, November 2020 Dry Storage and Transportation of High Burnup Spent Nuclear Fuel 36