ML25010A390
| ML25010A390 | |
| Person / Time | |
|---|---|
| Site: | 07109341 |
| Issue date: | 01/15/2025 |
| From: | Storage and Transportation Licensing Branch |
| To: | |
| Shared Package | |
| ML25010A388 | List: |
| References | |
| EPID EPID L-2023-LLA-0090 | |
| Download: ML25010A390 (1) | |
Text
Enclosure UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Request for Additional Information Docket No. 71-9341 Certificate of Compliance No. 9341 Model No. BRR Package By letter dated August 26, 2024 (Agencywide Documents Access and Management System Accession No. ML24239A866), Orano Federal Services LLC submitted an amendment request for the Model No. BEA Research Reactor (BRR) Package to (i) add, as authorized contents, the low enriched uranium (LEU) versions of the currently authorized high enriched uranium (HEU) research reactor fuels and (ii) encapsulated and segmented PWR fuel rod segments within a Rods-In-Tubes Canister (RITC) basket. Your application was accepted for review on October 18, 2024.
This request for additional information identifies information needed by the U.S. Nuclear Regulatory Commission staff in connection with its review of the application.
Each question describes information needed by the staff for it to complete its review of the application and to determine whether the applicant has demonstrated compliance with regulatory requirements.
Structural Evaluation 1 Provide detailed technical justifications for not performing the structural analyses with free drop orientations [i.e., center-of-gravity-over (CG-over) corner drop and oblique angle drops]
for the RITC and RITC basket under NCT and demonstrate or explain how the RITC and RITC basket comply with Title 10 of the Code of Federal Regulations (10 CFR) 71.71(c)(7).
The applicant performed the structural analyses of the RITC and RITC basket with two free drop orientations (end drop and side drop) under NCT (Reference 1). However, the applicant did not perform the structural analyses with other free drop orientations (i.e., CG-over corner drop and oblique angle drops) for the RITC and RITC basket under NCT. As required by 10 CFR 71.71(c)(7) a package needs to be demonstrated for structural adequacy by a free drop through the distance specified in 10 CFR 71.71(c)(7) onto a flat, essentially unyielding, horizontal surface, striking the surface in a position for which maximum damage is expected (Reference 2). In general, the drop orientations of 90° (vertical end), 0° (horizontal side), oblique angles (30°, 45°and 60°) and CG-over corner are considered in the structural analyses to find the location and magnitude of the maximum damage expected in the structural package system. Therefore, the applicant is requested to provide detailed technical justifications for not performing the structural analyses of the RITC and RITC basket with oblique angle drops including the CG-over corner drop under NCT and demonstrate or explain how the RITC and RITC basket meet the requirements of 10 CFR 71.71(c)(7).
This information is required to determine compliance with 10 CFR 71.71(c)(7).
2 Provide detailed technical justifications for not performing the structural analyses for the RITC and RITC basket under the hypothetical accident conditions (HAC) and demonstrate or explain how the RITC and RITC basket comply with 10 CFR 71.73(c)(1).
The applicant performed the structural analyses of the RITC and RITC basket for two free drops (end drop and side drop) under NCT, but did not perform the structural analyses under HAC. The applicant provided a brief statement in section 2.12.8.9, RITC Basket, RITC, and RIT, of the safety analysis report (SAR), in which it states, The RITC and RITC basket are not required to control the separation of the fuel rod segments during an HAC event. Therefore, only the RIT is evaluated for the bounding HAC 120g free drop load. However, no justification was provided for this statement.
Therefore, the staff requests to: (i) provide detailed technical justifications for not performing the structural analyses of the RITC and RITC basket under HAC, and (ii) demonstrate or explain how those justifications comply with 10 CFR 71.73(c)(1), which requires a free drop of a package through a distance of 30 ft. onto a flat, essentially unyielding, horizontal surface, striking the surface in a position for which maximum damage is expected.
This information is required to determine compliance with 10 CFR 71.73(c)(1).
3 Provide detailed technical justifications for not performing the structural analyses with free drop orientations [i.e., CG-over corner drop and oblique angle drops] for the Rods-In-Tubes (RITs) under NCT and HAC and demonstrate or explain how the RITs comply with 10 CFR 71.71(c)(7) and 71.73(c)(1).
The applicant performed the structural analyses for two RITs (A3 and A4 assemblies) in section 2.12.8.9.1, RIT, of the SAR. The A3 assembly was analyzed with two orientations (end drop and side drop) under NCT and HAC, while the A4 assembly was analyzed with only one orientation (end drop) under NCT and HAC. The applicant explained that the A4 assembly was not analyzed for the side drop because the A4 assembly is supported by the RITC tube over its full length, which is acceptable to the staff.
However, the applicant did not perform the analyses for both A3 and A4 assemblies with other free drop orientations [i.e., CG-over corner drop and oblique angle drops) under NCT and HAC. Since both 10 CFR 71.71(c)(7) and 71.73(c)(1) require that a package needs to be demonstrated for structural adequacy by a free drop through a specified distance onto a flat, essentially unyielding, horizontal surface, striking the surface in a position for which maximum damage is expected, the applicant would need to consider evaluating the RITs with other free drop orientations (i.e., CG-over corner drop and oblique angle drops) under NCT and HAC. Therefore, the applicant is requested to provide detailed technical discussions and information to demonstrate compliance with the NCT requirements of 10 CFR 71.71(c)(7) and HAC requirements of 10 CFR 71.73(c)(1).
This information is required to determine compliance with 10 CFR 71.71(c)(7) and 71.73(c)(1).
References:
1.
Orano Federal Services LLC Letter to U. S. Nuclear Regulatory Commission, Submittal of BEA Research Reactor Package CoC Amendment and CoC Renewal Request, Docket No.
71-9341, EPID L-2023-LLA-0090, dated August 26, 2024, with:
- - BEA Research Reactor Package Safety Analysis Report, Rev. 19, and
- - BEA Research Reactor Package Table of Changes for BRR SAR, Rev.
19.
Thermal Evaluation 1
Provide calculations (e.g., Excel file) to show derivation of the thermal properties (thermal conductivity and specific heat) of the MURR HEU Fuel Plate for verification.
The applicant provided thermal properties of the fuel element materials of MURR HEU Fuel Plate, MITR-II HEU Fuel Plate, ATR HEU Fuel Plate 1, ATR HEU Fuel Plate 2 to 18, and ATR HEU Fuel Plate 19 in SAR table 3.2-2. The applicant noted, in SAR table 3.2-2, that these material properties are determined based on composite value of aluminum cladding and fuel core material (see SAR appendix 3.5.3.9, Determination of Composite Thermal Properties for HEU Fuel Plates, and SAR table 3.5-1 for ATR HEU Fuel Plate, table 3.5-2 for MITR-II HEU Fuel Plate, and table 3.5-3 for MURR HEU Fuel Plate).
The applicant needs to provide calculations (e.g., Excel file) to show derivation of the thermal properties of the MURR HEU Fuel Plate, mentioned above, for staffs review verification. The calculations (e.g., Excel file) should include parameters of the MURR HEU Fuel Plate, such as x1, x2, k1, k2, cp1, cp2, 1 and 2.
This information is required to determine compliance with 10 CFR 71.35.
2 (A) Clarify, in the application, whether a personnel barrier is required for installation on the BRR package when transporting each payload of MURR HEU fuel, MITR-II HEU fuel, ATR HEU fuel, RITC payload, MURR LEU fuel, MITR-II LEU fuel, and ATR LEU fuel.
(B) Define Note (1) in Max. Accessible Surface (1) of SAR table 3.8.1-1.
The applicant performed the NCT thermal analysis with an ambient 100 °F and no solar heat when packaging the MURR HEU fuel with a bounding heat load of 1,264 W among HEU fuels. The applicant included thermal barrier in thermal model and predicted a maximum accessible package surface temperature of 185 °F (see SAR table 3.3-1). The applicant also performed NCT thermal analyses of MITR-II HEU fuel with a maximum heat load of 1,200 W per shipment and ATR HEU fuel with a maximum heat load of 240 W per shipment, as described in SAR section 3.2.
The applicant performed NCT thermal analysis without thermal barrier in thermal model when packaging the rod-in-tube canister (RITC) payload with a maximum heat load of 180 W, as described in SAR section 3.7.
The applicant performed thermal analysis for NCT with thermal barrier in thermal model when packaging MURR LEU fuel (1,264 W), MITR-II (1,200 W), or ATR LEU fuel (960 W).
The applicant predicted the maximum accessible package surface temperatures of 183
°F for MURR LEU fuel (SAR table 3.8.3-1), 183 °F for MITR-II LEU fuel (SAR table 3.8.3-2) and 155 °F for ATR LEU fuel (SAR table 3.8.3-3).
With analyses, mentioned above, either including or not including personnel barrier in the thermal model, the applicant needs to clarify, in SAR Chapter 3, Thermal Evaluation or Chapter 7, Package Operation, whether a personnel barrier is required when transporting each payload of MURR HEU fuel, MITR-II HEU fuel, ATR HEU fuel, RITC payload, MURR LEU fuel, MITR-II LEU fuel, and ATR LEU fuel.
This information is required to determine compliance with 10 CFR 71.43(g).
3 Provide the requested information on items (A) and (B) below for clarification on maximum normal operating pressure (MNOP) calculations.
The applicant calculated MNOPs for package loaded with MURR HEU fuel (SAR section 3.2.2) and ATR LEU fuel (SAR section 3.8.3.2) by assuming that the cavity gas reaches a bulk average temperature that is equal to the mean of the average inner shell temperature and the average fuel basket temperature.
The staff needs to verify whether a mean of the average inner shell temperature and the average fuel basket temperature is appropriate for MNOP calculations when there are differences in mass and structure configuration between inner shell and fuel basket.
(A) Provide the cask cavity bulk gas temperature, directly computed for fill gas from the thermal model, for each of MURR HEU fuel and ATR LEU fuel loaded in the package.
This request is to confirm that use of the mean of the average inner shell temperature and the average fuel basket temperature is appropriate for MNOP calculation.
(B) Provide the average inner shell temperature and the average fuel basket temperature in SAR tables 3.3-1 (MURR HEU fuel), 3.3-2 (MITR-II HEU fuel), 3.3-3 (ATR HEU fuel), 3.8.3-1 (MURR LEU fuel), 3.8.3-2 (MITR-II LEU fuel), and 3.8.3-3 (ATR LEU fuel) under NCT.
The applicant calculated the MNOP for package loaded with RITC payload by predicting the cask cavity bulk gas temperature from the gas sub model (SAR sections 3.7.3.2 and Note 1 on SAR table 3.7-1).
(C) Provide explanation of the gas sub model in SAR.
This information is required to determine compliance with 10 CFR 71.71.
4 Provide the rationale (or base) of the assumptions (underlined below) and their impact to thermal evaluation of the package transporting the RITC payload.
The applicant listed, in SAR section 3.7.5.1, five assumptions to highlight their importance for RITC analytical thermal model. The applicant needs to explain rationale (or base) and/or their impact to thermal evaluation on two assumptions: (1) the thermal properties of the aluminum materials are assumed in the annealed condition, and (2) the material properties of the fuel segment material properties are calculated using an assumed irradiation burnup of 62 GWd/MTU and a pellet density of 95 percent which results in reasonable values for the pellet conductivity and specific heat.
Note - Aluminum in an annealed condition is a metal that has been through a heat-treating process to restore its crystalline grain structure and make it easier to shape.
This information is required to determine compliance with 10 CFR 71.71 and 71.73(c)(4).
5 Provide a source book or Reference #51, as shown in SAR section 3.8.2.2 (page 3.8-5),
to illustrate that Equation (Tb = 3.25 x 107 f-0.2282) and a peak fission density of 8 x 1021 fissions/cm3 are appropriate for determining the LEU fuel plate temperature limit of 620 °F during vacuum drying.
The applicant stated, in SAR section 3.8.2.2, that the maximum allowable temperature limits for LEU fuel plate are 400 °F, 1100 °F, and 620 °F during NCT, HAC, and vacuum drying, respectively. The applicant noted that the aluminum fuel plate is not relied upon for structural strength of the fuel during vacuum drying operations, and therefore an allowable temperature based on the foil material may be used.
The applicant used a peak fission density of 8 x1021 fissions/cm3 to derive the lower bounding permissible cladding temperature limit of 620 °F, based on Equation (Tb = 3.25 x 107 f-0.2282).
The applicant needs to provide pages from the source book or the Reference #51 which is shown in SAR page 3.8-5 to support and illustrate Eqn. (Tb = 3.25 x 107 f-0.2282) and a peak fission density of 8 x 1021 fissions/cm3 are appropriate for determining the LEU fuel plate temperature limit of 620 °F during vacuum drying.
This information is required to determine compliance with 10 CFR 71.35.
6 Explain how the indefinite operation for vacuum drying of the LEU fuels is determined and whether a time duration limit is needed to ensure the fuel temperature will not continue heating up to reach 620 °F limit.
The applicant used the ATR LEU fuel as the bounding LEU fuel and stated, in SAR section 3.8.3.3, that the computed peak fuel plate temperature of 552 °F, under steady-state conditions, will require a total of approximately 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> to achieve (see SAR figure 3.8.3-14), and therefore, with the peak fuel temperature of 552 °F well below the 620 °F limit established in SAR section 3.8.2.2, indefinite operation under either air (or nitrogen gas) filled conditions or vacuum drying is permissible for in-facility operations.
The staff reviewed SAR figure 3.8.3-14 and noted that the ATR fuel temperature continues to increase after 480 minutes and a time duration limit is still needed to ensure the vacuum drying is completed before reaching the 620 °F limit, based on extrapolation of the transient trend shown in SAR figure 3.8.3-14.
The applicant needs to explain how the indefinite operation for vacuum drying for LEU fuels is determined and whether a time duration limit is needed to ensure the fuel temperature will not continue heating up to reach 620 °F limit.
This information is required to determine compliance with 10 CFR 71.35 and 70.71.
7 Explain the phrase of one-hour time period in SAR section 3.6.3.4 and assess whether a tracking of the elapsed time is required to take six hours to cool down the peak fuel plate temperature below 400 °F.
The applicant stated, in SAR section 3.8.3.4, that the one hour time-period following helium gas backfill required to reduce the peak fuel plate temperature below 400 °F is so short compared with the time to complete preparation of the cask for transport that no specific tracking of the elapsed time will be required.
The staff noted, from SAR figure 3.8.3-15, that it will take six hours (360 minutes),
instead of one hour, to reduce the peak fuel plate temperature below 400 °F. Therefore, the applicant needs to explain the phrase of one-hour time-period and assess whether a tracking of the elapsed time is required to take six hours to cool down the peak fuel plate temperature below 400 °F.
This information is required to determine compliance with 10 CFR 71.35 and 70.71.
Criticality Evaluation 1
Provide more information regarding the use of Whisper in determining the bias and bias uncertainty, and the calculation of the upper subcritical limit (USL).
Guidance recommends the usage of a methodology consistent with American National Standards Institute/American Nuclear Society-8.1. Insufficient information was included in the application for staff to make this determination.
This information is required to determine compliance with 10 CFR 71.55.
Package Operations 1
Add package surface temperature survey in SAR chapter 7 (e.g., section 7.1.4, Preparation for Transport) for an exclusive-use shipment of BRR package loaded with each fuel type of MURR HEU fuel, MITR-II HEU fuel, MURR LEU fuel and MITR-II LEU fuel in compliance with 10 CFR 71.43(g).
The maximum accessible surface temperature for BRR packaging with each fuel type of MURR HEU fuel (SAR table 3.3-1), MITR-II HEU fuel (table 3.3-2), MURR LEU fuel (table 3.8.3-1) and MITR-II LEU fuel (table 3.8.3-2), under NCT without solar heat, could be close to 185 °F limit in an exclusive-use shipment.
The applicant needs to add package surface temperature survey in SAR section 7.1.4, Preparation for Transport, to ensure that the maximum package surface temperature is below 185 °F for an exclusive-use shipment of BRR package loaded with each fuel type of MURR HEU fuel, MITR-II HEU fuel, MURR LEU fuel and MITR-II LEU fuel.
This information is required to determine compliance with 10 CFR 71.43(g).