ML24044A118
| ML24044A118 | |
| Person / Time | |
|---|---|
| Site: | 07103035 |
| Issue date: | 06/27/2023 |
| From: | Boyle R US Dept of Transportation (DOT), Office of Hazardous Materials Safety |
| To: | Garcia-Santos N Storage and Transportation Licensing Branch |
| References | |
| CAC 001794, EPID L-2023-DOT-0006 | |
| Download: ML24044A118 (1) | |
Text
U.S. Department East Building, PHH-23 of Transportation 1200 New Jersey Avenue SE Washington, D.C. 20590 Pipeline and Hazardous Materials Safety Administration
June 27, 2023 Norma Garcia Santos, Project Manager Storage and Transportation Licensing Branch Division of Fuel Management Office of Nuclear Material Safety and Safeguards (NMSS)
U.S. Nuclear Regulatory Commission 11545 Rockville Pike Rockville, MD 20852-2738
Dear Ms. Garcia Santos:
In accordance with the Memorandum of Understanding between our agencies, on April 3, 2023, I requested that you review the Japanese Certificate of Approval No. J/2045/B(U)F, Model No. JRC -
80Y-20T transport package and make a recommendation concerning our revalidation of the package for import and export use (Agencywide Documents Access and Management System
[ADAMS] Accession Number ML23115A074 and EPID L-2023-DOT-0006). On June 14, 2023, you sent a Request for Additional Information (RAI) regarding this review.
Our applicants response to your RAI was received and is enclosed. Please note our applicant found no proprietary information in your RAI and did not include any in th eir reply.
If you have any questions or need any additional safety information, please feel free to contact me at (202) 697-1301 or via email at rick.boyle@dot.gov.
Sincerely,
Richard W. Boyle, Radioactive Materials Division of Sciences and Engineering Office of Hazardous Materials Safety
Enclosure
Request for Additional Information U.S. Department of Transportation Japanese Approval Certificate No. J/2045/B(U)F Docket No. 71-3035 Certificate of Compliance No. 3035 Model No. JRC-80Y-20T
By letter April 3, 2023 (Agencywide Documents Access and Management System [ADAMS]
Accession Number ML23115A074), you submitted an application to the U.S. Nuclear Regulatory Commission (NRC) for the review of the Japanese Certificate of Competent Authority No. J/2045/B(U)F, Model No. JRC-80Y-20T package. In your application you requested that the NRC provides a recommendation to revalidate the Model No. JRC-80Y-20T.
This request for additional information (RAI) identifies information needed by the NRC staff (the staff) in connection with its review of the application. The staff used International Atomic Energy Agency (IAEA) Specific Safety Requirements No. 6 (SSR-6), Regulations for the Safe Transport of Radioactive Material, 2018 Edition, in its review of the application.
The RAI describes information needed by the staff to complete its review of the application and to determine whether the applicant has demonstrated compliance with the regulatory requirements of the IAEA SSR-6, 2018 Edition.
GENERAL INFORMATION
RAI-GEN-1 Replace all references to the IAEA transport safety regulations in the safety analysis report (SAR) for the Model No. JRC -80Y-20T to appropriately reflect the IAEA SSR-6, Revision 1 (2018 Edition).
For example, in Revision 1 of the S AR for the Model No. JRC-80Y-20T SAR, on page (II)-1, Chapter II: Safety analyses states: that the JRC package has been designed to comply with the IAEA Regulations for the Safe Transport of Radioactive Material 2012 Edition. H owever, since the SAR has been revised to meet the requirements of the IAEA SSR -6, Revision 1 (2018) and the SAR should accurately reference the applicable version or revision of the SSR-6 that the application complies with.
This information is needed to determine compliancet with the requirements in Paragraph 102 the IAEA SSR -6, 2018 Edition.
MATERIALS EVALUATION
RAI-Ma-1 Provide a description of any national or international codes, standards, and/or other methods, programs, or procedures that are implemented to ensure that package maintenance activities (including visual inspections, screening and evaluation of visual indications, and corrective actions such as component repairs and replacements) are adequate to manage the effects of aging in
Enclosure metallic package components that would see long-term use, such that the package components are capable of performing their requisite safety functions throughout the period of use.
The staff requests that this description address the following criteria:
- a. Inspection methods (e.g., bare metal visual exams and/or other types of nondestructive exams such as liquid penetrant exams or ultrasonic exams) for detection, characterization, and sizing of localized aging effects such as cracks, pits, and crevice corrosion.
In accordance with Section (III): A and B, each inspection is conducted during the annual periodic inspection or pre-shipment inspection (before transportation), and aging is also evaluated.
- b. Inspection equipment and personnel qualification requirements (e.g., lighting and visual acuity requirements for performing visual exams) to ensure reliable inspections that can adequately detect and characterize indications of localized aging effects prior to component failure or loss of safety function.
In accordance with Section (III), each inspection is conducted during the pre-shipment inspection (before transportation) or annual periodic inspection, and aging deterioration is also evaluated.
Each inspection is conducted by an inspector certified by JAEA. The visual inspection is conducted mainly by the inspector under adequate lighting. In each inspection, the measuring instruments used are calibrated with standards.
- c. Acceptance criteria for aging effects such as early stage fatigue cracks and localized corrosion of stainless steel components, such as chloride induced stress corrosion cracking (SCC), pitting, and crevice corrosion.
Examples of visual indications that may indicate potential localized corrosion of stainless steel components include the accumulation of atmospheric deposits such as salts, buildup of corrosion products, rust-colored stains or deposits, and surface discontinuities or flaws associated with pitting, crevice corrosion, and/or SCC.
As a consideration of changes over time, corrosion is evaluated from a chemical point of view, as indicated in Section (II), chapter F of the application, and is evaluated as having no effect.
As for the possibility of showing localized corrosion, the appearance is checked during the pre-dispatch inspection (before transport) or during the annual periodic inspection, in accordance with Section (III).
- d. Describe any surface cleaning requirements that are implemented to ensure that bare metal visual inspections of component surfaces are capable of detecting surface flaws, and for ensuring adequate removal of atmospheric deposits such as salts or other chemical compounds that may contribute to localized corrosion of stainless steel components.
Enclosure As a consideration of aging, corrosion is evaluated from a chemical point of view as indicated in Section (II), chapter F of the application, and is evaluated as no effect.
As for the elimination of causes, the external appearance is checked during the pre-dispatch inspection (before transportation) or during the annual periodic inspection in accordance with Section (III). In the inspection, surfaces are also cleaned (using cloths, etc.).
- e. Describe any flaw evaluation methods (such as flaw sizing and flaw analysis methods) and associated flaw acceptance criteria that may be used to determine whether components containing flaws are acceptable for continued service.
The criteria for the visual inspection are in accordance with Section (II),
and are checked from the viewpoint of "no cracks, abnormal scratches, deformation, etc." These are judged as detrimental flaws if they affect safety analysis, for example.
Per IAEA SSG-26, Advisory Material for the IAEA Regulations for the Safe Transport of Radioactive Material, 2018 Edition, Paragraph 613A.3:
For packagings intended for repeated use, the effects of ageing mechanisms on the package should be evaluated during the design phase in the demonstration of compliance with the Transport Regulations.
Based on this evaluation, an inspection and maintenance programme should be developed. The programme should be structure so that the assumptions (e.g., thickness of containment wall, leaktightness, neutron absorber effectiveness) used in the demonstration of compliance of the package are confirmed to be valid through the lifetime of the packaging.
The staff was not able to locate a detailed description of national or international codes, standards, and/or other methods, programs, or procedures that are implemented to ensure that package maintenance activities are adequate to manage the effects of aging in metallic package components that would see long-term use.
This information is needed to determine compliance with the requirements in Paragraphs 503(e), 613A, and 809(f) of the IAEA SSR -6, 2018 Edition.
RAI-Ma-2 Provide an evaluation of abrasion as an aging mechanism for the JRC-80Y-20T package.
Per IAEA SSG-26, 2018 Edition, Paragraph 613A.1:
The designer of a package should evaluate the potential degradation phenomena over time, such as corrosion, abrasion, fatigue, crack propagation, changes of material compositions or mechanical properties due to thermal loadings or radiation, generation of decomposition gases and the impact of these phenomena on performance of safety functions.
Enclosure The staff was not able to locate a discussion on abrasion being evaluated as an aging mechanism.
We believe that the evaluations (heat, radiation, corrosion, and fatigue) indicated in Section (II), chapter F of the application are the ones that require consideration, and that no consideration is required for abrasion as this package is not equipped with dynamic devices, etc.
This information is needed to determine compliance with the requirements in Paragraph 613A of the IAEA SSR -6, 2018 Edition.
RAI-Ma-3 Provide the aging management program (per the structure and procedure in IAEA SSG-26, Paragraph 613A.3 (2018 Edition) ) and gap analysis program.
Per IAEA SSG -26, Paragraph 613A.5:
For designs of Type B(U), B(M) and Type C packages these programmes are required to be included in the application for approval of packages for shipment after storage (see paras 809(f) and (k) of the Transport Regulations). The results of the ageing management programme and the gap analysis programme should be taken into account when preparing an inspection plan prior to transport.
The staff was not able to locate an aging management program or gap analysis program as required by IAEA SSR-6, Paragraphs 809(f) and (k).
This information is needed to determine compliance with the requirements in Paragraphs 809(f) and (k) of the IAEA SSR-6, 2018 Edition.
In accordance with Section (III) of the safety analysis document, each inspection will be conducted during pre-shipment inspections (before transport) or annual periodic inspections, and age-related deterioration will also be evaluated.
Therefore, it is our belief that this evaluation is included in the safety analysis document.
RAI-Ma-3 Provide a comparison between the maximum temperature expected during transport to the qualified temperature limit for the aluminum alloy cladding material.
In SAR Section F.2, the applicant describes heat related aging mechanisms that can affect the aluminum alloy, stating that thermal analysis indicated a substantial temperature difference between the maximum temperature expected during transport and the melting temperature of the aluminum alloy. However, the aluminum alloy cladding material has a much lower melting temperature.
This information is needed to determine compliance with requirements in Paragraph 613A of the IAEA SSR -6, 2018 Edition.
The maximum temperature expected during transportation is 223°C (Section (II)
B4.2), which is below the temperature at which aluminum alloys melt, 660°C (Section (II) B2).
Enclosure STRUCTURAL EVALUATION
RAI-St-1 Provide a complete evaluation of fatigue for the reusable package components for the 7 0-year period of use that considers the combined effects of all applicable types of accumulated stress cycles in components during normal service conditions, including the following cycle types (as described in this question):
- a. Lifting cycles
- b. Pressurization cycles
- c. Thermal stress cycles
- d. Vibration cycles
The staff needs a complete fatigue evaluation that considers the combined effects of all applicable types of stress cycles during normal service, including consideration of the cycle types listed above. Also, the appropriate number of cycles need to be considered in fatigue evaluation depending upon the type of cycle being evaluated. If certain types of stress cycles are not applicable or negligible for certain components, explain why these are not applicable or are negligible.
If such a complete fatigue evaluation cannot be performed, or if the fatigue evaluation cannot show adequate protection against fatigue failure considering the combined effects of all applicable types of accumulated stress cycles in components, provide the following information:
a.1 a description about how periodic maintenance inspections will be used to identify and address fatigue cracks in components of the package.
During the periodic annual inspections, the integrity of the package is confirmed through visual inspections of the package components and liquid penetrant testing of the welding points of the package body lifting device and lid lifting device to confirm whether or not there are any defects.
b.1 A description of the corrective actions that will be taken for any detected fatigue cracks, such as analytical flaw evaluation with follow-up inspections, repair/replacement of components with cracks, etc.
Fatigue cracks may occur at welding points between the package body and the lifting device, and at various bolts.
Repair of welds should be carried out in the same way as repair of weld defects that may occur in the manufacturing process of packages (Chapter IV-II: Modification of packaging, A.3.4 Repair of weld defects).
Various bolts should be replaced because they are standardized components.
Enclosure The following items provide additional descriptions about accumulated stress cycles as provided in the application:
- 1. Lifting cycles - The staff recognizes that these cycles are already evaluated in Section (II)-A.4.4.2.1.3, (II) -A.4.4.2.2.4 and Table (II)-F.2 of the SAR. However, the staff noted that the lifting cycles are evaluated without considering the other types of stress cycles that may also be accumulated by the lifting devices for the cask body and the lid. To perform an adequate analytical evaluation that demonstrates sufficient safety margin against fatigue failure of these components, the combined effects of accumulated lifting cycles along with other applicable types of accumulated stress cycles in these components (including consideration of cycle types listed herein) on the potential for fatigue of lifting devices should be considered.
The lifting device is attached to the outside of the package (Figure C.1 in Section (I)), so the stresses caused by the pressurization cycle and thermal stress cycle do not need to be considered. In addition, in this calculation, evaluation was conducted at the welds between the package body and the lifting device, which are the most vulnerable area when the lifting device is subjected to stress (A.4.4 2.1.1 2) and A.4.4 2.1.3), and it is natural that the fatigue potential of other components of the package, such as the lid and floor, is lower than that of the welds (the risk of fatigue failure is lower than that of welds). The SAR values submitted are based on the welds. Since the submitted SAR values are calculated based on the welds, it can be said that other components of the pac kage are sufficiently included in the safe side if fatigue failure does not occur in the welds.
- 2. Pressurization and thermal stress cycles - The staff recognize that pressure and thermal cycles are already evaluated in Sections ( II)-
A.5.1.3.3 and Table II-F.2. However, the staff noted that the containment device pressurization and thermal cycles are only evaluated for the most critical component, the lid bolt considering 300 cycles (frequency of 4 times per year for handling sealing device) over 70 years. Also, the staff noted that thermal stress cycles may occur in components due to cyclical fluctuation of spatial temperature gradients within components, which could significantly exceed 300 cycles over 70-year service life. In addition, the staff noted that this evaluation does not address the potential for fatigue of package components due to the combined effects of pressurization and thermal stress cycles with other types of stress cycles that may also be accumulated by the containment device components. To perform an adequate analytical evaluation that demonstrates sufficient safety margin against fatigue failure of these components, the combined effects of accumulated pressurization and thermal cycles along with other applicable types of accumulated stress cycles in these components (including consideration of cycle types listed herein) on the potential for fatigue of containment device components should be considered.
The basis for the 300 cycles is "4 cycles/year x 70 years x margin" as stated in A.5.1.4. The four times/year is the total of four times: two times
Enclosure for tightening the bolts after the annual voluntary inspection and fuel loading on the Japanese side, and two times for tightening on the U.S.
side, assuming that the same measures are taken as on the Japanese side, since the actual situation on the U.S. side is unknown. Among these, the state in which the fuel is actually stored (a state in which thermal stress must be taken into account) is only once, when the lid is tightened after the fuel is loaded on the Japanese side. Therefore, 300 cycles is the number of cycles considered on the safety side and is not likely to be significantly exceeded.
The concern about thermal stress cycles due to spatial temperature changes is calculated in the thermal stress (Table A.5.1.2 3.2, Section (II)
Chapter-B.6) under the condition that the maximum temperature at the time of fuel element A storage always continues during normal transportation (-40°C to 38°C environment), which is evaluated in the SAR.
The combined effect of the stresses is calculated at the stresses (115 MPa) with the initial clamping force added to the thermal stresses and maximum internal pressure maintained above (summary: A.5.1.4 3.2; thermal stresses: A.5.1.1, B.4.2, B.4.5; maximum internal pressure: B.4.4, B.6.3; initial (See A.4.4 2.2.2 1)) The combined effects of thermal stress cycles and pressurization cycles are considered, so it can be said to be in accordance with the current requirements. As for other combined effects, as mentioned in 1-A, there is no need to consider the lifting cycle because it is not caused by the location of the lifting equipment.
- 3. Vibration cycles - The staff noted that section (II)-A.4.7 provide an evaluation that demonstrates that package resonance is a not a concern considering package vibration caused by vehicle transport. However, the staff noted that this evaluation does not address the potential for fatigue of the package and tie-down components due to the combined effects of the accumulation of many vibration cycles resulting from the allowed transports of the package over 70- year service life (with each transport experiencing long distance travel over potentially rough roads), along with the accumulation of other applicable types of stress cycles, including consideration of the cycle types listed herein.
Regarding the possibility of resonance, the maximum vibration frequency during transportation was calculated to be 50 Hz, taking into account rough roads and long distances. As described in A.4.7, there is no influence of load amplification due to vibration during transportation, and considering the fact that the package is not deformed even when a load of 5 times its own weight plus its own weight is applied in the evaluation of stacking under general test conditions (A.5.4), there is no risk of cracks or damage to the package caused by vibration during transportation. Even if it is considered that no deformation will occur even if the package is subjected to five times its own weight plus dead weight load, there is no risk of cracks, damage, etc. to the package due to vibrations that occur during transportation.
As the lashing equipment is designed to be an integral part of the package (Figure A.1 in Section (I))and the increase in weight of the package when combined with the lashing equipment is slight, its natural period is also slightly reduced. Therefore, there is no danger of resonance. Therefore, there is no need to consider the lashing equipment as well.
Enclosure To determine that fatigue as not an aging concern, as indicated in Section (II)-F of the application, the staff needs a complete fatigue evaluation that considers the combined effects of all applicable types of stress cycles during normal service, including consideration of the cycle types listed above. Also, the appropriate number of cycles need to be considered in fatigue evaluation depending upon the type of cycle being evaluated.
This information is needed to determine compliance with the requirements in Paragraphs 503(e), 613, 613A, and 809(f) of the IAEA SSR -6, 2018 Edition.
Enclosure