ML24145A136
| ML24145A136 | |
| Person / Time | |
|---|---|
| Site: | 07109384 |
| Issue date: | 06/05/2024 |
| From: | Storage and Transportation Licensing Branch |
| To: | |
| Shared Package | |
| ML24145A133 | List: |
| References | |
| EPID L-2024-NEW-0003 | |
| Download: ML24145A136 (1) | |
Text
Enclosure 2 Observations Docket No. 71-9384 Model No. RT-200 Type B(U) Transportation Cask These observations allow you to start earlier on items that may be asked at a later date.
Observations are not the result of a detailed technical review and may be resolved once staff begins a detailed review. Responses to observations are not required for staff to begin its technical review.
The observations are listed by technical discipline of review.
I.
OBSERVATIONS A. Thermal Evaluation (Th)
OBS-Th-1 Clarify how the package thermal model represents the condition of the package during transport and demonstrate that the steady-state and transient thermal analyses are properly converged.
The safety analysis report (SAR) Thermal chapter provided limited discussion of the packages boundary conditions and, therefore, it is uncertain if there are intermediate transport structures surrounding the package during transport (e.g., container, tarps). Similarly, section 6.3.3 of the thermal calculation package (RT-200 NTE 3002 C) noted a constant ambient convection heat transfer coefficient but did not demonstrate that it bounded the packages transport condition (e.g.,
circumferential effects, surface temperature dependence). Finally, there was no information confirming appropriate steady-state spatial resolution (e.g., grid convergence), transient time-step value resolution, and thermal model convergence (e.g., residuals).
This information is needed to determine compliance with Title 10 of the Code of Federal Regulations (10 CFR) Section 71.35.
B. Containment Evaluation (Co)
OBS-Co-1P1 Provide the amount of time that the O-ring temperature can remain above the normal/continuous operations maximum allowable temperature limit and up to [Information Withheld Pursuant to 10 CFR 2.390]
(depending on the O-ring manufacturer) in the application (e.g., SAR section 4.6.3). Also clarify the allowable elastomer O-ring temperature range, in SAR table 4.6.3-1 and SAR section 8.1.5.2, for normal/continuous operations.
The applicant provided the operating temperatures from three different 1 Observations containing or referencing proprietary information are identified with the letter P.
manufacturers data documents in SAR section 4.6.3.2 and defined the temperature range of ethylene-propylene-diene-monomer (EPDM) in SAR table 4.6.3-1. Table 4.6.3-1 shows an elastomeric O-ring temperature range of [Information Withheld Pursuant to 10 CFR 2.390] for the normal/continuous operations and a temperature of [Information Withheld Pursuant to 10 CFR 2.390], depending on the O-ring manufacturer, for a short period of time. However, the amount of time for the short period has not been provided for each O-ring manufacturer.
However, the applicant stated, in SAR section 8.1.5.2, that the normal/continuous operating temperature shall be in a narrower allowable temperature range of -40 °C to 120 °C (SAR chapter 8 is included in the Certificate of Compliance).
This information is required to determine compliance with 10 CFR 71.51(a)(1) and (2).
OBS-Co-2 Define the containment boundary components of the RT-200 package more precisely in SAR chapter 4 Also clarify whether the closure bolts associated with the lid, vent port cover plate, and drain port cover plate are part of the containment boundary components.
The applicant stated, in SAR section 4.1.1, that the package containment system is defined as the containment vessel (the inner shell, the rear forging plate and the front forging flange), together with the associated lid, O-rings and lid closure bolts. The applicant described the containment penetrations (i.e., lid, vent cover plate, and drain cover plate) in SAR section 4.1.2. The applicant also described the containment welds and O-rings in SAR section 4.1.3.
However, SAR figure 4.6-1 appeared to indicate that the containment boundary components include the following: the containment vessel (the inner shell, the rear forging plate, and the front forging flange) together with the lid, the inner O-rings for the lid, vent port cover plate, and drain port cover plate, the cover plates at vent port and drain port, and the containment welds. It could be clearer to, in addition, describe the entire containment boundary in SAR section 4.1.1, as is briefly described in section 1.2.1.3 of the SAR.
The American National Standards Institute (ANSI) N14.5, American National Standard for Radioactive Material - Leakage Tests on Packages for Shipment, defines the containment boundary as, The designated boundary of the containment system, which is designed to prevent leakage of radioactive material. The containment boundary may include the containment vessel, shell, welds, seals, lids, cover plates, and valves. This basically means items that are in contact with the fluid being contained, and the lid and vent and drain port cover plate closure bolts are not in contact with the fluid. The lid and vent and drain port closure bolts are part of the closure system though that compresses the containment boundary O-rings, which are part of the containment boundary. The application should clarify whether the closure bolts associated with the lid, vent port cover plate and drain port cover plate are part of the containment boundary components (these bolts are not shown in SAR figure 4.6-1).
This information is required to determine compliance with 10 CFR 71.33(a)(4) and 71.43(c).
OBS-Co-3 Provide responses to 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 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 percent 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 Geff, = 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 (Geff) and the maximum allowable shipping time (tmax), assuming that the package is drained with a dewatering criterion of 10 percent, 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 (GH2 = 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).
OBS-Co-4 Describe the alternative method used to determine the shipping time to reach the required hydrogen concentration of 5 volume percent, 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 volume percent. 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 users to follow.
This information is required to determine compliance with 10 CFR 71.43(d).