ML24304A911
| ML24304A911 | |
| Person / Time | |
|---|---|
| Site: | 07109384 |
| Issue date: | 10/30/2024 |
| From: | Robatel Technologies |
| To: | Document Control Desk, Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML24304A901 | List: |
| References | |
| 2021-034-SCL-02 | |
| Download: ML24304A911 (1) | |
Text
Robatel Technologies 5115 Bernard Dr. Suite 304 Roanoke, VA 24018
October 30, 2024
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738
Subject:
Robatel Technologies R esponse to A ddress the U.S. NRC Request for Additional Information for R eview of the Robatel Technologies, LLC Model No. RT-200 Type B(U) Cask
Reference:
ADAMS Accession No. ML24222A718, dated August 30, 2024
This response addresses the Requests for Additional Information ( RAIs) noted on the U.S. NRC request for additional information letter, dated August 30, 20 24. The RAIs are listed by technical discipline of review, along with Robatels response.
This response where applicable, references the locations in the SAR where revised information can be located.
General Information (G)
RAI-G -1
Clarify where the information related to impact limiters is discussed.
The applicant in safety analysis report (SAR) section 1.2.1.1 stated that the two impact limiters consist of stainless-steel casings filled with foam. However, section 3.1 states that the impact limiters are made from a foam material as detailed in Chapter 8, section 8.5.1.
This information is required by the staff to determine compliance with 10 CFR 71.33.
Response RAI-G -1
In order to ensure the descriptions of the impact limiters in the SAR are consistent throughout the various SAR sections, Robatel has amended section 3.1 of the SAR.
Impact:
Section 3.1 of the SAR revision 0: The impact limiters are made from a foam material, as detailed in Chapter 8, Section 8.1.5.1 has been amended as follows in revision 1: The impact limiters consist of stainless-steel casings filled with foam, as detail ed in Chapter 8, Section 8.1.5.1.
This response letter regarding the Part 71 Application for Approval of RT-200 Type B Cask Package for Radioactive Material represents Robatels approach to its business as applied to the specifications of this submittal. This response letter requests that the Nuclear Regulatory Commission respects the proprietary information and withholds it from public disclosure subject to the provisions of 10 CFR 2.390.
Structural Evaluation (St)
RAI-St-1
Provide the details of how the h ypothetical accident conditions (HAC) puncture test satisfied 10 CFR Part 71.73(c)(3).
In safety analysis report (SAR) section 2.7.3.1.1.2, 3D Puncture Model Boundary Conditions, the puncture load is applied to a 150 mm diameter region which corresponds to a 150 mm diameter pin. The load is simulated with an evenly distributed pressure load equal to the dynamic flow stress of the pin. The dynamic flow stress is taken to be 324 MPa corresponding to 5% plastic deformation in the pin. Explain the methodology for calculating the 5% deformation of the pin as a result of the impact considering the 1-m drop required by the regulation.
This information is needed to determine compliance with 10 CFR Part 71.73(c)(3).
Response RAI-St -1 The dynamic flow stress of 324 MPa was based on precedent of NRC accepted SARs. The value of the dynamic flow stress will be calculated based on the material properties of the mild steel (reference 10 CFR 71.73(c)(3)). The SAR section 2.7.3.1.1.2 and appendices will be updated to provide the details of the analysis.
The puncture analysis will be updated with the new value of dynamic flow stress calculated (350 MPa).
Impact: Appendix added to NTE 2004, SAR section 2.7.3.1.1.2, SAR section 2.7.3.2.2.
2
RAI-St-3
Provide the time step used for the transient analysis, clarify whether an implicit or explicit solution mode was selected and why such solution is selected for this analysis.
In SAR section 2.6 NORMAL CONDITIONS OF TRANSPORT, and 2.7 HYPOTHETICAL ACCIDENT CONDITIONS, the same methodology of two-step analysis is used for various drop analyses. These two analyses include a calculation of the crushing forces and g-loads of the cask RT -200 NTE 2101, Drop Calculations, and a structural FE analysis RT-200 NTE 2004, Cask Body Calculations, using the first calculation result as an input. The applicant stated that, with all other boundary conditions applied, a transient structural analysis is performed using Impact Limiter Reaction Force vs. time curve as analysis input. In RT-200 NTE 2101, RT-200 -
Drop Calculations, Revision B, sections 7.1.1 to 7.2.3, various drop test result curves are presented using a 0.01ms time step. However, in RT-200 NTE 2004, RT-200 - Cask Body Calculations, the time step is not identified for transit analysis. In addition, it is not clear whether an explicit or implicit method is used for transient analysis and whether the performed analysis is suitable for such a short duration of the impact load.
This information is needed to determine compliance with 10 CFR Part 71.71(c)(7) and 71.73(c)(1).
Response RAI-St -3
The initial time step in the FE calculation has been set to 0.01 ms.
The calculations were performed using an implicit method. Such a method gives solutions that are generally more reliable. However, they are also more difficult to converge to a solution.
When convergence is not achieved, explicit calculations may be used.
In this case, the calculations succeed in converging with the implicit method. Therefore, there is no reason to use explicit methods.
Impact: No impact on the SAR.
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PROPRIETARY/TRADE SECRET INFORMATION REMOVED -
WITHHELD FROM PUBLIC DISCLOSURE UNDER 10 CFR 2.390
Impact: No impact in the SAR.
RAI-Th -2
Clarify that the package is open to the ambient during transport and there are no covers that would adversely affect thermal performance of the package.
Although safety analysis report (SAR) section 1.2.1.5 indicated that personnel barriers are not required to meet dose limits, it was not clear to the staff if a covering is used during transport operations. Correspondingly, it was not clear in SAR Chapter 7, Package Operations, whether evaluations would be performed to ensure a covering, if it were to be used, would not adversely affect thermal performance of the package.
This information is needed to determine compliance with 10 CFR 71.35.
Response RAI-Th-2
Only a rain cover is expected to be used. The rain cover will provide adequate clearance and ventilation to not affect the thermal performance of the package. Section 7.1.3 has been updated to provide requirements for protective barriers that may be used.
Impact:
Section 7.1.3. Step 12
RAI-Th -3
Clarify that the emissivity and absorptivity of the packages outer surface will be maintained during operations.
Thermal calculation document (RT-200-NTE 3002 Rev. C) section 6.6.3 and table 8 stated that the thermal analyses were based on the packages outer surface having an absorptivity of 0.4.
Considering that the condition of the packages outer surface can change over time due to exposure with the ambient and that a 0.4 absorptivity value may not exist after the fire due to soot, there was no sensitivity analysis performed regarding absorptivity and thermal performance and no clarification in the SARs Acceptance Tests and Maintenance Program chapter that procedures are in place to ensure the surfaces low absorptivity value.
This information is needed to determine compliance with 10 CFR 71.35.
Response RAI-Th-3P
In normal conditions of transport, the thermal emissivity was set to This is penalizing since it limits the heat exchanges and increases the cask temperatures. On the other hand, the solar absorptivity was set to 0.4, which is a typical
9
This information is required to determine compliance with 10 CFR 71.33(a)(4) and 71.43(c).
Response RAI-Co -2 Chapter 1 and Chapter 4 have been updated to ensure consistency throughout the SAR. The bolts are not formally part of the containment boundary, however they do contribute to maintaining the containment boundary.
Section 4.1.1. states that the hex bolts are a part of the containment boundary but they are not.
There is a later description of the bolts that states they hold the lid on. The bolts maintain the containment boundary by attaching the lid but are not a par t of the containment boundary as they do not contact the contents.
Sections 4.1.1. and 1.2.1.3. have been edited to remove the bolts from the list of items that make up the containment boundary and add a description that the bolts maintain the boundary but are not a part of it.
Impact:
Sections 4.1.1. and 1.2.1.3. have been edited to remove the bolts from the list of items that make up the containment boundary and add a description that the bolts maintain the boundary but are not a part of it.
RAI-Co -3
Provide responses on items (A) and (B) below, which are related to package draining and hydrogen gas generation, as described in SAR sections 4.5, 4.6.6, and 7.5, to ensure that hydrogen generation in the package cavity will be below 5 volume percent (vol%) throughout the entire shipping period:
(A) describe the procedure in the application (e.g., SAR chapter 7) for verification that a dewatering criterion of 10% or less is met through the draining operation, and
(B) provide adequate information to justify the assumption that the energy absorbed from alpha particles is defined by a 0.01 fraction or consider a conservative approach to assume that all decay energy is in the form of alpha decay ( = 1.0 and G eff, = 1.60).
The applicant described hydrogen gas generation in SAR sections 4.5 and 7.5.1 and provided example of hydrogen gas generation calculations in SAR sections 4.6.6 and 7.5.2. The applicant referred to NUREG/CR-6673, Hydrogen Gas Generation in TRU Waste Transportation Packages, to derive equations for the effective G value (G eff) and the maximum allowable shipping time (tmax), assuming that the package is drained with a dewatering criterion of 10%, a fraction of 0.01 for the decay energy due to alpha decay ( GH2 = 1.60) and a fraction of 0.99 for the decay energy due to beta and gamma decay (G H2 = 0.45).
Section 3.3.1.1 of the NUREG/CR-6673 notes: In many instances, detailed information concerning the radionuclides and their concentrations in a waste material may be unavailable, and determination of the separate decay fractions (,, ) may not be possible. For most waste types and waste configurations, a conservative approach is to assume that all decay energy is in the form of alpha decay, but the conservatism of this approach needs to be justified.
This information is required by the staff to determine compliance with 10 CFR 71.43(d).
13 Response RAI-Co -3
(A)
The cask will be drained into a graduated container that allows for quick visual indication of the amount of water removed. The volume of the contents will be known and can be subtracted from the empty cavity volume to determine the expected water content. This value will be compared against the amount of water actually removed. If there is greater than 10% residual water by mass, this will be mitigated through operational procedures.
(B)
SAR section 4.6.6 and section 7.5.2. provide examples calculation for hydrogen gas generation.
It is up to the user to define the input values and ensure an adequate shipping time. The fraction of decay energy due to alpha decay may change depending on the contents.
However, a bounding example calculation has been added, adopting the more conservative approach on determination of the shipping timeframe to increase the safety margin.
Impact:
(A)
Section 7.1.2.4 of the SAR has been amended to indicate that a suitable drainage system that is capable of measuring the volume of water removed from the cask shall be used.
(B)
Section 4.6.6. and 7.5. of the SAR have been updated to add a bounding example based on the bounding/conservative conditions ( = 1.0 and G eff, = 1.60).
RAI-Co -4
Describe the alternative method used to determine the shipping time to reach the required hydrogen concentration of 5 volume percent (vol%), in accordance with NUREG/CR -6673, and clarify that similar results to the method in SAR section 7.5 would be achieved.
The applicant stated, in SAR section 7.5.3, that alternatively, the user can follow another applicable method in accordance with NUREG/CR -6673 to determine the shipping time to reach the required hydrogen concentration of 5 vol%. However, the applicant does not provide sufficient details of the alternative process and procedures in the application to ensure similar performance would be achieved. The applicant should provide details of the alternative method in the SAR (e.g., chapter 7 or chapter 8) for user s to follow.
This information is required to determine compliance with 10 CFR 71.43(d).
Response RAI-Co -4 SAR section 7.5.3 will be removed.
Impact:
SAR section 7.5.3 is removed.
14 RAI-Co -5
Clarify the following items in table 8.3.2-1 of the SAR to be consistent with ANSI N14.5.
SAR table 8.3.2-1 provides the maximum leakage rate of 1 x 10 -3 ref-cm 3/sec for the vent/drain ports and the maximum leakage rate of L He (e.g., 1.0 x 10-7 ref-cm 3/sec) for the vent/drain port cover plates. SAR figure 4.6-1 illustrates that the vent (or drain) port cover plate is located next to the vent (or drain) port to cover the vent (or drain) port. It is unclear to the staff:
(A) Why the allowable leakage rate of L He for the vent/drain port cover plates is different from the allowable leakage rate of 1.0 x 10 -3 ref-cm 3/sec for the vent/drain port.
(B) How the leakage rates are measured at the vent/drain ports and at the vent/drain port cover plates when the maximum allowable leak rates are different, and the ports are covered/enclosed by port cover plates?
(C) Whether the vent and drain ports in the sixth row of table 8.3.2-1 refer to the lid, vent and drain port O-rings and whether they are tested to: No leakage at a sensitivity (< 1x10 -3 ref-cm 3/sec), or (< LHe).
(D) Whether the empty cask, cask lid, vent port cover plate, and drain port cover plate material in the seventh row needs to be tested annually, or alternatively, whether this row refers to a combination of: 1. the ANSI N14.5 periodic leakage rate testing on the lid, vent, and drain port O-rin gs performed within 12 months prior to shipment and 2. the ANSI N14.5 maintenance leakage rate testing performed prior to returning a package to service following maintenance, repair, or replacement of components of a containment boundary. Describing the ANSI N14.5 periodic leakage rate testing in one row and ANSI N14.5 maintenance leakage rate testing in another row could be a clearer option.
(E) Whether the two rows, at the bottom of SAR table 8.3.2-1, that describe the pre-shipment leakage rate testing on Cask Lid and Vent and Drain Port Cover Plates, refers to the associated O-rings.
This information is necessary to clarify that the containment boundary components are being tested in accordance with ANSI N14.5.
This information is required to determine compliance with 10 CFR 71.51(a)(1) and (a)(2).
Response RAI-Co -5 P
(A) The vent/drain port is not part of the containment boundary unlike the vent/drain port cover plate assemblies. The acceptance criteria for leakage rate is therefore different.
(B) During the leakage test after fabrication, vent/drain ports and vent/drain port cover plate assemblies are tested separately with different allowable leakage rate (see answer A) and different control method:
- For the vent/drain port cover plate assemblies, the A.5.4 Evacuated Envelope (gas detector) method can be used. For this method the vent/drain port must be removed.
The method involves pressurizing the inner cavity (with a test gas (usually helium) while the seal interspace of the cover plate is placed in a vacuum chamber connected to a gas detector. A schematic diagram illustrating this method is provided below.
15 PROPRIETARY/TRADE SECRET INFORMATION REMOVED -
WITHHELD FROM PUBLIC DISCLOSURE UNDER 10 CFR 2.390
- For the vent/drain port, the A.5.2 Gas Pressure Rise (vacuum retention) method can be used. For this method the cover plates must be removed and replaced by a test device. The method involves evacuating the test cavity (space between the vent/drain port and the vacuum chamber) and measuring a pressure rise during a specified test period. A schematic diagram illustrating this method is provided below.
(C) The vent and drain ports in the sixth row of Table 8.3.2-1 of Rev. 0 of the SAR refers only to the quick-disconnect valve and not the cover plate assembly.
(D) Table 8.3.2-1 in Rev. 0 of the SAR is divided into four tables in Rev. 1 of the SAR to clarify at what steps the cask components are to be tested.
(E) A note has been added to clarify what is included in the cover plate assemblies.
16 Impact:
SAR Section 8.3.2 - Table 8.3.2-1 has been divided into four tables and notes have been added for clarification.
RAI-Co -6
(A) Describe/provide either the methodology or the procedure, used to determine the helium permeation time for the elastomeric O-rings, in the application (e.g., SAR chapter 7) for the users to follow.
(B) Provide source books or References with pages showing the permeation time of the elastomeric O-rings used for RT-200 package.
(C) Provide the procedures in SAR chapter 7 or 8 to distinguish the permeation from the helium leakage for the helium leakage rate test.
The applicant stated, in SAR section 8.1.4, that (1) the containment system includes the elastomeric O-rings and therefore permeation can be a problem when a leakage rate test procedure is being used to demonstrate that the system is leak tight, and (2) th e degree of permeation is affected by seal material, seal surface area, time, and temperature. The applicant referred to recommendations of ANSI N14.5 to be considered to eliminate permeability as a factor in leakage rate measurements, and stated, in SAR s ection 8.1.4, that the test duration should be such as (System Response Time < Test Duration < Helium Permeation Time).
The staff accepts that the test duration should be such as (System Response Time < Test Duration < Helium Permeation Time). However, instead of the statement that the degree of permeation is affected by seal material, seal surface area, time, and temperature, the applicant needs to describe either the methodology or the procedure, used to determine/derive the helium permeation time, for the users to follow at their own loading operations (e.g., maintenance and periodic leakage rate tests). The applicant needs to provide source books or References with pages illustrating the permeation time of the elastomeric O -rings used for RT-200 package.
The applicant needs to provide information, requested above, in the application (e.g., SAR chapter 7) to ensure that the derived helium permeation time for the elastomeric O -rings is acceptable and the helium leakage rate testing is reliable at the sites.
This information is required to determine compliance with 10 CFR 71.51(a)(1) and (a)(2).
Response RAI-Co -6
Note has been added to section 8.1.4 that provides guidelines to determine the helium permeation rate and permeation time for the elastomeric O -rings.
Impact:
§8.1.4: Adding of the following note:
The permeation rate or time for the elastomeric O -rings of the cask can be determined either by tests (measurement of the evolution over time of the permeation rate up to steady -state) or by calculations relying on equations provided by appendix D.8 of IS O 12807 standard [Ref.73]
(basing for instance on data from Gas Permeation through Common Elastomer Sealing Materials, Vuoto scientific paper referred in ISO12807 standard [Ref.73] as reference [5])
17
RAI-Co -7
Provide the procedures of the leakage rate tests in the application (e.g., SAR chapter 8). The procedures should describe measurement of the helium leak rate (step by step) when the tracer gas used in the leakage rate test is a mixture of helium and air.
The applicant stated, in SAR section 4.4.2, that the leakage tests may be performed with an air/helium mixture and the helium component (L He) of this leak rate (Lmix) is determined by multiplying the leak rate of the mixture by the ratio of the helium partial pressure to the total mix pressure (LHe = Lmix PHe / Pmix).
The applicant noted, in SAR section 8.1.4, that the partial pressure of the tracer gas (e.g.,
helium) in the envelope should be at least 10% of the total gas pressure and must be known, consistent with the statement by ANSI N14.5 (section A.3.6) that the partial pressure of tracer gas in the test mixture should be at least 10% of the total pressure and must be known.
Besides providing an example calculation of the air/helium mixture in SAR section 4.4.2, the applicant needs to provide procedures of the leakage rate tests using the air/helium mixture in the application (e.g., SAR chapter 8).
This information is required to determine compliance with 10 CFR 71.51(a)(1) and (a)(2).
Response RAI-Co -7 The steps and considerations necessary to properly perform the helium leak testing will be added to Section 8.1.4
Impact:
Added minimum requirements for leak test procedures to Section 8.1.4
RAI-Co -8
Describe or revise the use of the term, Welded seals, in SAR section 8.1.5.2.
The applicant stated, in SAR section 8.1.5.2, that in the case of welded seals when manufacturing large diameter O-rings from a single cord, the joint must be made using hot vulcanization. Gluing is prohibited. However, the applicant has not described the use of welded seals for containment boundary components in other parts of the application.
This information is required to determine compliance with 10 CFR 71.33(a)(4) and 71.51(a)(1) and (a)(2).
Response RAI-Co -8 Vulcanized O-rings are made from a single cord with both ends fused together. In section 8.1.5.2 the term welded seals means vulcanized O -rings.
Impact:
To avoid any misunderstanding, the sentence has been modified in SAR Sec tion 8.1.5.2 as
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PROPRIETARY/TRADE SECRET INFORMATION REMOVED -
WITHHELD FROM PUBLIC DISCLOSURE UNDER 10 CFR 2.390
Impact:
Section 4.1.4 of SAR has been updated to include this information.
Materials Evaluation (Ma)
RAI-Ma -1
Provide the materials specifications (SA240, SA479, etc.) for important to safety (ITS) materials in RT-200 Bill of Materials, Section 1.3.3 of the SAR.
The applicant described the fabrication of the RT-200 system in SAR Section 2.1.4, and stated that containment components are fabricated in accordance with ASME Boiler and Pressure Vessel (B&PV) Code,Section III, Subsection NCD and non-containment components in accordance with Subsection NF. The staff understands that these applicable subsections of ASME B&PV Code require materials that conform to the requirements of one of the specifications for materials given in ASME B&PV Code,Section II Part D per Section NCD -2121 and Section NF-2121, respectively. However, the applicant did not provide the material specifications for the ITS materials in the SAR. The staff needs the materials specifications for ITS materials in RT-200 Bill of Materials, Section 1.3.3 of the SAR to verify that the package is designed and constructed in accordance with ASME B&PV Code,Section III.
This information is needed to confirm compliance with 10 CFR 71.31(c), 71.33(a)(5), 71.35(a),
71.51(a).
Response RAI-Ma -1
Robatel has added in RT-200 Bill of Materials, Section 1.3.3 of the SAR a column for ITS components made of stainless-steel to provide the ASME specifications that must be followed.
However, not all ITS components have applicable B&PVC sections (for example: lead, ceramic paper, etc.): Section 2.1.4 of the SAR has therefore also been amended to clarify that not all ITS components have applicable B&PVC sections and to add the relevant section to the BoM where applicable.
Impact:
Column added in RT-200 Bill of Materials, Section 1.3.3 of the SAR for providing ASME specifications for ITS components made of stainless -steel.
Clarification in Section 2.1.4 of the SAR about ITS components.
Operations (Op)
RAI-OP -1 Revise section 7.1.1.3, Drain and Vent Port Cover Plate Removal, section 7.1.2.3, Cask Lid Replacement, and section 7.1.2.5, Drain and Vent Port Cover Plate, to point the user to follow the prerequisite steps in section 7.1.1, when damage and remediate as appropriately is mentioned these sections. Operational steps in section 7.1.1 will require the user to perform maintenance leakage rate testing in accordance with section 8.2.2.1 prior to returning a
20 package to service following maintenance, repair (such as a weld repair), or replacement of components of a containment boundary.
The applicant in SAR sections 7.1.1.3, Drain and Vent Port Cover Plate Removal, 7.1.2.3, Cask Lid Replacement, and 7.1.2.5, Drain and Vent Port Cover Plate Replacement, stated in part, that when signs of damage and remediate as appropriate but does n ot point to specific section of the SAR for the user to follow for remediate actions.
This information is needed to meet the requirements of 10 CFR 71.87 and 71.111.
Response RAI-OP -1
A note has been added to Sections 7.1.1.3. Drain and Vent Port Cover Plate Removal, 7.1.1.4.
Cask Lid Removal, 7.1.2.3. Cask Lid Replacement, and 7.1.2.5. Drain and Vent Port C over Pl ate Replacement to reference Section 7.1.1. Preparation for Loading for instructions on inspection and maintenance.
Section 7.1.1. Preparation for Loading has been updated to add a reference to Table 8.3.2-3 RT-200 Leakage Test Types - Annual/Maintenance Tests
An additional note has been added to Section 7.1.1.3. to clarify that the drain port cover plate shall be inspected post removal.
Impact: SAR Sections 7.1.1., 7.1.1.3., 7.1.1.4., 7.1.2.3., 7.1.2.5.
RAI-OP -2
Clarify or modify the removal and replacement procedures for the impact limiters.
Section 7.1.1.2 describes a general procedure for removing/replacement of front and rear impact limiters; however, the operational procedure does not provide the loading sequence operations for removal of each impact limiter and securing the cask to prevent dropping or damage. If rear impact limiter is removed prior to the front impact limiter or vice versa, indicate how the package will be lifted, and cask secured and protected from damage. Provide detail sequence of steps illustrated by a visual diagram of the loading operation.
This information is needed to meet the requirements of 10 CFR 7.87 and 71.111.
Response RAI-OP -2
Clarifications have been added to the SAR instructions (Chapter 7) for the impact limiters removal and replacement:
- No specific requirement about the order of removing/replacing the impact limiters.
- The impact limiters shall be removed prior to lifting the cask.
- Adding of a visual diagram to illustrate the main steps for a loading operation.
21 Impact:
Section 7.1: adding of the following clarification: A visual diagram is provided in appendix to illustrate the main steps for the cask loading operation that are detailed below.
Section 7.1.1.1: adding of the following clarification: The order of removing the respective impact limiters shall be determined by the cask user in accordance with a method that will prevent damage.
Section 7.1.1.2: adding of the following clarification: Note that the impact limiters shall be removed in accordance with Section 7.1.1.1 prior to lifting the cask.
Appendix 7.6: Adding of a visual diagram related to cask loading main steps in appendix 7.6.2
RAI-OP -3
Describe/provide the methodology or procedure in SAR section 7.1.1.5, for removing freestanding water from the basket.
The applicant in SAR section 7.1.1.5 stated that the basket and the interior of the cask shall be visually inspected to verify they are undamaged, free of debris, and freestanding water removed. However, the applicant did not include operational steps for removing freestanding water from the basket.
This information is needed to meet the requirements of 10 CFR 71.111.
Response RAI-OP -3
"Freestanding water is removed" may be removed from this section as the beginning of the section states that this is applicable to initial loading of the basket, in which case there will be no freestanding water present, or if the basket is not present in which case the basket and cask will already have been verified to have freestanding water removed (reference 7.2.2 step 6.).
Impact: SAR Section 7.1.1.5
RAI-OP -4
Discuss the need to prevent contamination during unloading.
(A) The potential for release of radioactive gases, volatiles, etc., as well as combustible gases, from the package during unloading (such as quick -disconnect valve failure, etc.) of contents should be discussed, especially in Section 7.2.2 (B) If available, provide field data that shows the activity from the void/headspace from a package with the proposed contents.
This information is needed to meet the requirements of 10 CFR 71.43(d), (f) and 71.51.
22
Response RAI-OP -4 Cautionary notes have been added to relevant sections to bring attention to the potential release of radioactive and/or volatile gases or material. There is currently no available field data that can be provided to show potential activity from the void/headspace of the proposed contents. Note that release of radioactive and/or volatile gas is mitigated through Section 7.1.1.3 step 5.
Impact: SAR Sections 7.1.1.3, 7.1.1.4, 7.1.1.5, 7.1.1.7, and 7.2.2
RAI-OP -5 Provide instructions in Chapter 7 that indicate contents are limited such that the concentration of combustible gases must be below 5%, by volume, at the end of the shipping period.
Chapter 7 should provide instructions to indicate that contents are limited such that the concentration of combustible gases must be below 5%, by volume, at the end of shipping period.
This information is needed to meet the requirements of 10 CFR 71.43(d).
Response RAI-OP -5
A note has been added to Section 7.5 Hydrogen Buildup in RT-200 Transport Cask to define the allowable hydrogen gas generation and provide reference to the procedure of freestanding water removal in Section 7.1.2.4 Cask Draining. The removal of free-standing water is critical to the limiting of hydrogen gas generation as free-standing water is the only contributor of hydrogen gas generation in the package.
Impact: SAR Section 7.5 Hydrogen Buildup in RT-200 Transport Cask:
The rate of hydrogen gas generation must also be considered when evaluating the heat load to ensure that a maximum of 5% by volume is maintained throughout the shipment. The procedure for cask draining is provided in Section 7.1.2.4 which when followed can ensure that the criterion of less than 10% of the water mass remains in the containment vessel. The method for calculating the hydrogen gas generation is described in Section 4.5.3.
RAI-OP -6
Provide operational steps in Chapter 7 after completion of last operation and before preparation of transport, to confirm the package has been loaded and closed in accordance with written procedures and that the final configuration is as shown in the SAR drawings.
This information is needed to meet the requirements of 10 CFR 71.87(f).
Response RAI-OP -6
A note has been added to Section 7.1.3. Preparation for Transport for the cask operator to ensure that all steps prior to the preparation of trans port have been completed in accordance
23
with the written procedures.
Impact: SAR Section 7.1.3.
RAI-OP -7
Provide additional operational procedures in section 7.4 related to: 1) removing package from the transport trailer, 2) reloading of package onto the transport trailer, and 3) tightening methods and equipment for torquing of components such as bolts and the acceptance criteria.
This information is needed to determine compliance with 10 CFR 71.43(f) and 71.51.
Response RAI-OP -7 A note has been added to Section 7.1.1.1 to remove the impact limiters in an order determined by the cask user and in a method that will prevent damage. A note has been added to Section 7.1.1.2 to specify that the impact limiters shall be removed in accordance with Section 7.1.1.1 prior to lifting the cask. A note has been added to Section 7.1.3 to verify that steps prior to preparation for transport have been completed, Section 7.2 outlines the package unloading procedure, and Section 7.3 outlines the procedure for preparation of an empty package for transport. Torque specifications with acceptable tolerances are called out where applicable.
Impact: SAR Section 7.1.1.1, Section 7.1.1.2, and Section 7.1.3
Acceptance and Maintenance Tests (AM)
RAI-AM -1
Provide the methodology or procedure for conducting leak rate test to be performed during fabrication, assembly and maintenance of RT-200 components. The procedure should include the test methodology, precautions, pre-test inspections, test parameters, personnel qualifications and acceptance criteria for the user to follow.
The applicant stated in SAR sections 8.2.2.1 and 8.2.2, that the test methods, leak test sensitivity and test acceptance criteria for all applicable equipment to be tested annually or after maintenance are located in Table 8.3.2-1. However, the leak test discussion in Chapter 7 and 8 lacks details as evidenced further in subsequent RAI comments. Confirm that appropriate leak testing procedure is established, per quality assurance requirements.
This information is needed to meet the requirements of 10 CFR 71.87 and 71.111.
Response RAI-AM -1
The leak test procedure to be performed during fabrication, assembly, and maintenance of RT-200 components is being developed in accordance with the information provided in the SAR,
including Table 8.3.2-1. The procedure will include the test methodology, precautions, pre-test
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inspections, test parameters, personnel qualifications, and acceptance criteria and will be made available to the users of the RT-200. Leak test procedures will be in accordance with the requirements stated in Section 8.1.4 and 8.2.2.
Impact: SAR Section 8.3.2 Table 8.3.2-1 through -4.
RAI-AM -2
Clearly indicate the dimensions, design criteria, fabrication criteria, and acceptance tests required for all important to safety, non-standard materials and components.
The Bill of Materials indicates O-rings, impact limiter foam, fusible plug and ceramic paper as non-standard items. In order to adequately describe the proposed design, provide either the detailed drawings showing dimensions, or include specific reference to the desired part. If a reference is provided, enough detail is needed to understand the design details of the specific component. Further, an understanding of the data that is used to develop material properties, design allowable, and acceptance tests for these components is needed. In SAR section 4.6.3.1, the applicant specifies elastomer seals from Parker, Trelleborg, and James Walker.
However, section 8.1.5 does not discuss the method of procurement of these non-standard components to ensure the materials meets all specifications critical to safety.
A description of those tests that are required to ensure the safety of the package is needed in Chapter 8 of the application. This can be accomplished by detailing the tests in Chapter 8. For example, for the impact limiter foam, a test matrix of the formulation, batch and pour tests required to ensure that the desired properties are achieved could be provided. Acceptance tests may also be proposed for the seals and the carbon fiber thermal shield. Alternatively, if this information is already contained in another document such as a commercial -grade dedication plan, that document can be referenced and provided as an appendix to Chapter 8. For procurement of non-standard materials used in RT -100 package, the applicant in RT -100 SAR section 8.1.5 stated that for these materials a commercial -grade dedication (CGD) plan is prepared to ensure that materials meet all specifications critical to safety and the CGD plan is prepared in accordance with RT quality assurance program requirements.
This information is needed to meet the requirements of 10 CFR 71.31(c), 71.33 (a)(5), 71.71, 71.73, and 71.85.
Response RAI-AM -2
Material and test requirements have been added as discussed in the following RAI responses.
Section 1.3.3, 1.3.4, and 1.3.5 provide all relevant dimensional details necessary.
Impact:
SAR Section 1.3.3 - Added column for applicable ASME section SAR Section 8.1.4 - Added requirements for leak testing during fabrication and following maintenance and/or repair.
SAR Section 8.1.5.1 - Added foam test requirements SAR Section 8.1.5.2 - Added O-ring critical characteristics SAR Section 8.1.5.3 - Added ceramic paper test requirements SAR Section 8.1.5.4 - Added fusible plug test requirements SAR Section 8.1.5.5 - Referenced Section 1.3.3 for applicable ASME section
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PROPRIETARY/TRADE SECRET INFORMATION REMOVED -
WITHHELD FROM PUBLIC DISCLOSURE UNDER 10 CFR 2.390
RAI-AM -3
Provide in details test methods, test standards, and acceptance criteria for verifying the physical characteristics of the O-rings in SAR Chapter 8 for test personnel to follow. Provide any supplementary physical properties tests to be performed to meet service requirements. In addition, the SAR should identify specific provisions of the quality assurance program requirements used in all aspects of the packaging testing.
The applicant stated in SAR section 2.2.2.1 that RT-200 utilizes seals formed from EPDM, a synthetic rubber elastomer. In section 4.6.3 the applicant provides information on the O -rings manufacturer, operating temperature range, gap permeability and compression set for the material. However, the SAR needs to include the test methodology, applicable test standards, and acceptance criteria for verifying the different critical characteristics (physical properties) of O-rings to ensure when fabricated they will provide positive sealing function.
This information is required to determine compliance with 10 CFR 71.51(a)(1) and (a)(2).
Response RAI-AM-3 The applicable test methods, test standards, and acceptance criteria for verifying the phys ical characteristics of the O-rings are provided by the associated ASME code. A table has been added to section 8.1.5.2. Elastomeric O -rings to add these ASME codes as well as provide the physical properties and critical characteristics of the Elastomeric O-rings, Table 8.1.5 -1 Critical Characteristics of Elastomer O-rings.
Additionally, an in-text reference to the critical characteristics has been added to section 4.6.3.
Elastomer Seal Temperature Specifications.
Impact:
Section 8.1.5.2. Added Table 8.1.5-1 Critical Characteristics of Elastomer O-rings Section 8.1.5.2. Added the following note: The critical characteristics of the O -Rings are described in Section 4.6.3. Elastomer Seal Temperature Specifications and are defined in Table 8.1.5-3 Critical Characteristics of Elastomer O-Rings below.
RAI-AM -4P
Describe/provide the acceptance standards and tolerance for verifying specific heat and thermal conductivity for ceramic paper.
The applicant listed in SAR section 1.3.3 the ceramic paper material to be ceramic fiber paper. Further, in tables 3.5-1 and 3.5-4 the applicant lists the temperature independent and temperature dependent material properties of the ceramic paper. However, the applicant has not specified the test methods, the test standards to be used and the acceptance criteria in SAR Chapter 8 or other parts of the application for the user to follow.
This information is needed to meet the requirements of 10 CFR 71.51 and 71.123.
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8.3-1. The equation to determine the leakage rate from pressure rise data should be provided in Chapter 8 or in detailed procedures that are available to package users.
This information is required by the staff to determine compliance with 10 CFR 71.87.
Response RAI-AM -6
Guidance to conduct pre -shipment pressure rise tests (according to the requirements related to these leak tests) has been added in section 8.3.2 of the c hapter 8 of the SAR, including equations to be used in such a case.
Impact:
Section 8.3.2 Adding of the following note:
According to ANSI N14.5, the purpose of the pre-shipment controls is to verify that no leak is detected during a test with a sensitivity of at least 10 -3 ref.cm3/s. In case of pressure rise method testing, this then consists in verifying that during a test whose duration (H) is greater (or equal) to the minimum required duration (Hmini), the detected pressure rise (pressure variation) doesnt exceed the accuracy of the gauge (p), ie:
and
RAI-AM -7
Provide reasonable justification for limiting the use of COFREND standard for certifying personnel for leakage testing of the RT-200 in Section 8.1.4 instead of American Society for Nondestructive Testing (ASNT) or revise the section of the SAR.
The applicant stated in SAR section 2.6.7.1 that the RT-200 is designed in accordance with the ASME Boiler and Pressure Vessel (B&PV) Code Section III, Division 1, and Regulatory Guide (RG) 7.6. The codes and standards used in the design of the RT-200 cask are selected based on guidance provided in the ASME Code [Ref. 13], RG 7.6 [Ref. 14] and NUREG/CR -3854 [Ref.
17] for packages transporting Category II contents.
28 RG 7.6 endorses the use of ASME B&PV Code Section III. ASME B&PV Code Section III, Division 1, Class 3, Subsection ND-5520 specifies personnel performing nondestructive examinations shall be qualified in accordance with the recommended guidelines of ASNT SNT-TC-1A, Recommended Practice for Nondestructive Testing. The endorsement of ASME Code Section III allows the applicants for and Certificate of Compliance holders to use ASNT SNT-TC -
1A referenced in the ASME Code for qualifying personnel performing nondestructive testing including leakage testing. COFREND standard has not been evaluated and approved by the Nuclear Regulatory Commission for U.S. commercial use.
This information is needed to meet the requirements of 10 CFR 71.87.
Response RAI-AM -7
An equivalency study between ASNT SNT-TC -1a 2006 and 2011 has been compared to ISO 9712 similar to what was done for the RT-100 SAR. This study determines that COFREND certification to ISO 9712 provides equivalent or higher requirements for level 2 and level 3 leak testing personnel. This equivalence study will be referenced in the SAR Section 8.1.4.
Impact: SAR Section 8.1.4
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