ML20150A269
| ML20150A269 | |
| Person / Time | |
|---|---|
| Site: | 07201029 |
| Issue date: | 05/28/2020 |
| From: | Office of Nuclear Material Safety and Safeguards |
| To: | |
| CFMarkley NMSS/DFM/STL 415.6293 | |
| Shared Package | |
| ML20150A267 | List: |
| References | |
| CAC 001028, EPID L-2019-RNW-0014 | |
| Download: ML20150A269 (12) | |
Text
REQUEST FOR ADDITIONAL INFORMATION TN Americas LLC Certificate of Compliance (CoC) No. 1029 Renewal Application Docket No. 72-1029 By letter dated May 22, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19148A484), and supplemented by letter dated December 4, 2019 (ML19338E132), TN Americas LLC (TN) submitted an application for renewal of Certificate of Compliance No. 1029 for the Standardized Advanced NUHOMS System. In my letter dated, January 16, 2020, I acknowledged acceptance of your application for a detailed technical review and provided a proposed schedule for the U.S. Nuclear Regulatory Commission (NRC) review (ADAMS Accession No. ML20009D205). This request for additional information (RAI) identifies information needed by the U.S. Nuclear Regulatory Commission (NRC) staff in connection with its technical review of the renewal application.
The requested information is listed by chapter number and title in the renewal application.
The staff used NUREG-1927, Revision 1, Standard Review Plan for Renewal of Specific Licenses and Certificates of Compliance for Dry Storage of Spent Nuclear Fuel and NUREG-2214, Managing Aging Processes In Storage (MAPS) Report in its review of the renewal application.
Each individual RAI describes information needed by the staff for it to complete its review of the renewal application and to determine whether the applicant has demonstrated compliance with the regulatory requirements. RAIs are designated sequentially by number and renewal application section (e.g., RAI N-S).
RAIs for CoC No. 1029 Renewal RAI 1-2. [PROP] Clarify the intended safety functions of the Safety Classification A components included in Drawing [ANUH-01-4006] and shown in certificate of compliance (CoC) renewal application Table 2-4 Scoping Evaluation for 32PTH2 dry shielded canisters (DSCs). These components which include the [ ] and the [ ] do not identify retrievability as a listed safety function.
The Standardized Advanced NUHOMS Final Safety Analysis Report (FSAR) Revision 7 Section B.1.1 (ML16228A019) states:
Provisions have been made, as discussed in Chapter B.2, for storage of up to 16 damaged CE 16 x 16 class fuel assemblies in lieu of an equal number of intact fuel assemblies in the cells located at the outer periphery of the 32PTH2 basket. The 32PTH2 DSC basket fuel compartments, which store damaged fuel assemblies, are provided with top and bottom end caps to assure retrievability. The physical and radiologic]al characteristics of these payloads are described in Chapter B.2.
Based on the FSAR description, it appears that these components are relied on for retrievability.
This information is needed to determined compliance with 10 CFR 72.236(m).
RAI 2-2. [Non PROP] Justify the Scoping Evaluation for Spent Fuel Assemblies subcomponents with a structural function included in CoC renewal application Table 2-7. The scoping evaluation does not identify Retrievability as a safety function for these fuel assembly subcomponents.
The Standardized Advanced NUHOMS Updated FSAR (ML16228A020) Section B.2.1.1 Detailed Payload Description states:
The 32PTH2 DSCs can accommodate up to a maximum of 16 damaged fuel assemblies placed in the outer fuel compartments of the 32PTH2 DSC as shown in Figure B.2.1-1. Damaged PWR fuel assemblies are assemblies containing missing or partial fuel rods, or fuel rods with known or suspected cladding defects greater than hairline cracks or pinhole leaks. The extent of damage in the fuel assembly is to be limited such that a fuel assembly is able to be handled by normal means. The 32PTH2 DSC basket fuel compartments which store damaged fuel assemblies are provided with top and bottom end caps.
Based on the response to OBS 2-1 (ML19338E132) and the description in Standardized Advanced NUHOMS UFSAR (ML16228A020) Section B.2.1.1, the design bases for the 32PTH2 DSC included in CoC No. 1029 Amendment 3 includes assembly based retrievability.
This information is needed to determined compliance with 10 CFR 72.236(m) and 10 CFR 72.240(c)
RAI 3-3. [Non PROP. Editorial] Add reference to CoC renewal application Section 3.C to Section 3.2.2 to clarify the sources of operational experience reviewed to support the identification of aging mechanisms and aging effects.
CoC renewal application Section 3.2.2 Identification of Aging Mechanisms and Aging Effects states:
After the component material/environment combinations are identified, potential aging mechanisms are determined. NUREG-2214 [3-2] is reviewed to identify potential aging degradation mechanisms for different materials and environments.
The operational experience reviewed and detailed in CoC renewal application Section 3.C is consistent with the information identified in NUREG-1927 Rev. 1 (ML16179A148) Section 3.6.1.10.
This information is needed to determined compliance with 10 CFR 72.240(c)
RAI 4-3. [Non PROP] Provide a technical justification for the assessment in CoC renewal application Section 3.5.3.2.4 Microbiologically Influenced Corrosion of Stainless Steel Material that microbiologically influenced corrosion is not a credible aging mechanism in embedded in concrete environments.
The bases for the assessment for Microbiologically Influenced Corrosion of stainless steel in Section 3.5.3.2.4 states:
In a helium environment, there are very little residual water and nutrients in internal environments of a DSC following drying and refilling with inert helium gas. Similarly, there are very little moisture and nutrients in an embedded-in-concrete or fully encased environment.
However, Section 3.5.3.1.4 Microbiologically Influenced Corrosion of Steel Material states:
In an embedded-in-concrete environment, if the concrete is exposed to a groundwater/soil environment and is degraded, the steel could be exposed to groundwater or soil. Under these conditions, the steel could be susceptible to MIC.
Therefore, MIC of the steel material is considered credible in an embedded-in-concrete environment if the concrete is exposed to a ground/soil environment, but is not credible in air-outdoor, sheltered, helium, or fully encased environments.
The staff note that the basis for the assessment that Microbiologically Influenced Corrosion of stainless steel is not credible based on the determination that there is very little moisture and nutrients in an embedded-in-concrete or fully encased environment (CoC renewal application Section 3.5.3.2.4) is not consistent with the assessment for Microbiologically Influenced Corrosion of Steel Material (CoC renewal application Section 3.5.3.1.4).
In addition, the staff note that NUREG-2214 Table 3-2 does not evaluate the potential for microbiologically influenced corrosion for stainless steel in an embedded in concrete environment. The evaluation was limited to embedded in metal (E-M) and embedded in neutron shielding (E-NS) environments.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 5-3. [PROP] Clarify or correct the information in Table 3C-1 TN Americas Internal Corrective Action Reports (CARs) Since CoC No. 1004 Renewal, [ ]. The Brief Description states:
[
]
The assessment states:
[
]
As written, the assessment does not address the potential effects of iron contamination of the stainless steel DSC shell.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 6-3. [PROP] Clarify or correct the information included in Tables 3-7, 3-11, 3-12 and 3-13 with respect to the potential for galvanic corrosion of stainless steel in contact with graphite lubricants. Table 3-7 Aging Management Review Results for DSCs includes galvanic corrosion as a credible aging mechanism for the following components: [ ]
Drawing [ ] (24PT1 DSC)
Drawing [ ] (24PT4 DSC)
Drawing [ ] (32PTH2 DSC).
However, galvanic corrosion was not included for the following Outer Bottom Cover Plate items in Tables 3-11, 3-12 and 3-13:
Table 3-11 (24PT1 DSC) [ ] (included for [ ])
Table 3-12 (24PT4 DSC) [ ] (included for [ ])
Table 3-13 (32PTH2 DSC) [ ].
Section 3.5.3.2.3 concluded that galvanic corrosion of stainless steel is credible in when in contact with graphite lubricants. Clarify why the Outer Bottom Cover Plate items in Tables 3-11, 3-12 and 3-13 were not considered to be susceptible to this aging effect.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 7-3. [PROP] Clarify or correct the information provided in Tables 3-14 and 3-15 for components that are constructed from [ ] and [ ] materials. In Tables 3-14 and 3-15 these materials are listed as "Steel under the Material Group heading. These materials should be classified as stainless steels and be assessed for the appropriate aging mechanisms, aging effects and have the appropriate aging management activity identified based on the results of the aging management review for the material and environment combination.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 8-3. The requested information was available, so this RAI was removed.
RAI 9-3. [Non PROP] Justify the exclusion of the potential role of iron contamination on in the supplemental evaluation of environmental parameters for chloride induced stress corrosion crackling included in Appendix 3B of the CoC renewal application.
CoC renewal application Section 3C.3.1 states:
There were three OE [operating experience]-related occurrences of rust on dry shielded canister (DSC) components due to improper storage prior to the DSCs being placed in service.
Previous canister inspection results including the systems inspected at the Calvert Cliffs Independent Spent Fuel Storage Installation have shown evidence of iron contamination (EPRI, 2014).
A previous Electric Power Research Institute (EPRI) report (EPRI, 2005) concluded that data on the SCC propensities of austenitic stainless steels in marine environments also indicate that SCC is exacerbated by the presence of several factors including iron contamination EPRI-1011820, Section 3.3.3, Minimum Chloride Level for SCC [stress corrosion cracking],
reports test results that shows for stainless steel pressurized tube tests, the time to failure was reduced by a factor of approximately two by the deposition of iron powder on the surface along with the sodium chloride. EPRI-1011820, Section 4.2.1 includes several examples where the presence of iron was significant in component failures.
References EPRI, Calvert Cliffs Stainless Steel Dry Storage Canister Inspection, EPRI-10252209, Palo Alto, CA, 2014.
EPRI, Effects of Marine Environments on Stress Corrosion Cracking of Austenitic Stainless Steels, EPRI-1011820, Palo Alto, CA, 2005.
This information is needed to determined compliance with 10 CFR 72.240(c)
RAI 10-A. [Non PROP] Include the aging effects and mechanism will be managed via the DSC Aging Management Program (AMP) into the Scope in Table A-2. Incorporate the following references into Table A-2:
4-2. Nuclear Energy Institute (NEI) 14-03, Format, Content, and Implementation Guidance for Cask Storage Operations-Based Aging Management, Revision 2, Nuclear Energy Institute, December 2016.
4-3. American Society of Mechanical Engineers, ASME Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plants and Fuel Processing Plants, 2017 Edition.
4-4. American Society of Mechanical Engineers, ASME Boiler and Pressure Vessel Code,Section III, Division 1, 1992 Edition, with 1994 Addenda, including exceptions allowed by Code Case N-595-1.
4-5. American Society of Mechanical Engineers, ASME Boiler and Pressure Vessel Code,Section III, Division 1, 2010 Edition.
4-6. Electric Power Research Institute, Aging Management Guidance to Address Potential Chloride-Induced Stress Corrosion Cracking of Welded Stainless Steel Canisters, EPRI-TR-3002008193, March 2017.
The ASME Code sections contain information relative to the design construction and inspection of the DSCs. The EPRI report and NEI 14-03 contain guidance that is significant for the CoC users. The staff note that only the information included in CoC renewal application Attachment A will be incorporated into the UFSAR and information with respect to the aging mechanisms and effects managed by the AMPs is considered necessary to ensure that general licensees implement and update, as necessary, AMPs to maintain their effectiveness.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 11-A. [Non PROP] Include the aging mechanisms and aging effects for carbon steel stainless steel and reinforced concrete managed via the HSM AMP in the scope in Table A-3.
Incorporate the following references into Table A-3:
4-2. NEI 14-03, Format, Content, and Implementation Guidance for Cask Storage Operations-Based Aging Management, Revision 2, Nuclear Energy Institute, December 2016.
4-9. ACI-349.3R, Evaluation of Existing Nuclear Safety Related Concrete Structures, American Concrete Institute, 2018.
The ACI Code contains information relative to the inspection of the HSMs. The NEI 14-03 document contain guidance that is significant for the CoC users. The staff note that only the information included in CoC renewal application Attachment A will be incorporated into the UFSAR.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 12-A. [Non PROP] Include the aging mechanisms and aging effects for carbon steel and reinforced concrete managed via the Basemat AMP in the scope in Table A-4. Incorporate the following references into Table A-4:
4-2. NEI 14-03, Format, Content, and Implementation Guidance for Cask Storage Operations-Based Aging Management, Revision 2, Nuclear Energy Institute, December 2016.
4-9. ACI-349.3R, Evaluation of Existing Nuclear Safety Related Concrete Structures, American Concrete Institute, 2018.
The ACI Code contains information relative to the inspection of the Basemat. The NEI 14-03 document contain guidance that is significant for the CoC users. The staff note that only the information included in CoC renewal application Attachment A will be incorporated into the UFSAR.
This information is needed to determined compliance with 10 CFR 72.240(c)
RAI 13-A. [Non PROP] Incorporate the following references into Table A-5:
4-2. NEI 14-03, Format, Content, and Implementation Guidance for Cask Storage Operations-Based Aging Management, Revision 2, Nuclear Energy Institute, December 2016.
The NEI 14-03 document contains guidance that is significant for the CoC users. The staff note that only the information included in CoC renewal application Attachment A will be incorporated into the UFSAR.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 14-4. [Non PROP] Clarify the following statement in CoC renewal application Section 4.3.4.2 Augmented Examination:
Locations inspected using surface or volumetric examination do not need to receive a VT-3 inspection.
It appears that this should refer to VT-1 inspection.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 15-4. [Non PROP] Provide the following information regarding the Augmented examination described in 4.3.6.2 DSC AMP - Augmented Examination.
- 1. Provide the code or standard for the surface and volumetric examinations identified in CoC renewal application Section 4.3.6.2. The applicant has stated in CoC renewal application Section 4.3.4.2 that visual examinations follow procedures consistent with the ASME B&PV Code,Section XI Subarticle IWA-2210.
- 2. Identify the required inputs for the engineering evaluation.
- 3. Explain the determination of uncertainty for the engineering evaluation when the input to the engineering evaluation is NDE data using unqualified examination procedures as indicated in CoC renewal application Section 4.3.4.2.
- 4. Explain the determination of uncertainty for the measured flaw size by volumetric examination data obtained using unqualified examination procedures as indicated in CoC renewal application Section 4.3.4.2.
- 5. Section 4.3.6.2 states:
If a volumetric examination is performed, no further actions are required if any of the following apply:
If the detected indication is determined to not be connected to the exterior of the DSC (i.e., not associated with the outside surface)
However, the augmented examination described in CoC renewal application Section 4.3.6.2 would only be implemented if the visual examination described in Section 4.3.4.2 identifies an indication that does not meet the acceptance criteria in Section 4.3.6. Explain how an indication
that is not connected to the exterior surface of the DSC could be detected by visual examination of the DSC exterior surface. It is understood that volumetric inspection of welds could result in identification of additional indications such as porosity or small areas of lack of fusion that were neither identified in NDE during fabrication nor detected in the remote visual examination.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 16-4. [Non PROP] Clarify how the consequence analysis described in Section 4.3.6.3 will be used.
The DSC AMP states that flaws that exceed the allowable size will be entered into the corrective action program, which will include a review of analyses related to the consequences of a through-wall CISCC. Clarify if the AMP may allow a though-wall crack and, if so, describe how a consequence analysis would be used to demonstrate compliance with the requirements of 10 CFR Part 72 to confine and ensure retrievability of the spent fuel.
This information is needed to determined compliance with 10 CFR 72.240(c)
RAI 17-4. [Non PROP] Clarify the evaluation of a minor corrosion indication under Section 4.3.6.1. DSC AMP - Visual Examination Criteria. It is not clear from the description here and in Table A-2 whether the presence of corrosion identified in this circumstance would be considered major corrosion.
From the description it appears that the all corrosion indications within 2 inches of the weld will get VT-1 or surface examination to determine if the corrosion indication is major or minor.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 18-4. [Non PROP] Provide the basis for the greater than 2 mm in diameter criteria for minor corrosion indications in Section 4.3.6.1 and Table A-2. Explain whether the indication has to be rounded or meet the non-linear, non-branching criteria. Explain how areas with corrosion products that are less than 2 mm in diameter will be assessed.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 19-4. [PROP] Provide a justification for the [ ] through wall crack as an allowable localized flaw.
Section 4.3.6.3 and Table A-2 of CoC No. 1029 renewal identify the [ ] through wall crack as an allowable flaw size. Section 3B.6 states that a DSC shell thickness of [ ] was adequate to maintain confinement. The staff noted that a thickness of [ ]
represents approximately a [ ] reduction of the DSC overall shell thickness.
The staff identified this issue during the RSI process and formulated Observation A-2. In response (ML19338E133), the licensee stated that the localized [ ] through wall criteria for cracks is not comparable to the minimum uniform DSC shell thickness [ ] requirement to maintain confinement but did not provide reason for this claim. Given that a minimum DSC
shell thickness is required to ensure adequate confinement boundary, provide justification for this claim.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 20-4. [Non PROP] Provide the following for the HSM AMP:
- 1. A technical justification for the use of visual inspections, rather than radiation surveys, to verify that the shielding function of the HSMs are not diminished.
NUREG-2214 Section 6.6 indicates that periodic radiation monitoring to show compliance with annual dose limits defined in 10 CFR 72.104(a) and radiation surveys performed to support compliance with 10 CFR Part 20 requirements for maintaining occupational exposures are not intended for identifying degradation of an individual storage systems concrete due to aging effects. The staff note that the NRC has conducted generic shielding evaluations for several storage system designs and identified instances where the use of visual inspections in lieu of radiation surveys may be justified (NRC, 2019). An applicant may reference the NRC evaluations, provided that (1) the applicant can justify that the NRC evaluations apply to, or are bounding for, the applicants design, including consideration of the assumptions and system parameters (both design and contents) used in the NRC evaluations and (2) the NRC evaluations indicate that the use of visual inspections for that design would be sufficiently conservative for ensuring against a loss of shielding performance.
- 2. A technical justification for examining a minimum of one HSM with a frequency of once every five years.
The staff note that NUREG-2214 Table 6-3 recommends annual general area walkdowns of all reinforced concrete structures that includes 100 percent of readily accessible surfaces (or a justified coverage) and 100 percent of normally inaccessible surfaces (or a justified coverage) of a subset of the reinforced concrete structures within the scope of renewal. A minimum of two of the same structures (i.e., same design bases) are evaluated at the minimum inspection frequency.
The staff also note that ACI 349.3R (ACI 2018) Chapter 6Evaluation Frequency states:
The frequency at which periodic evaluations are conducted using the evaluation procedure should be defined by the owner based on need.
Evaluation frequency should be based on the aggressiveness of environmental conditions and physical conditions of the plant structures.
The established frequencies should also ensure that any age-related degradation is detected at an early stage of degradation and appropriate mitigative actions can be implemented.
References NRC, Study of the ACI 349.3R-02 Tier 2 (i.e., Section 5.2.1) Criteria Impacts on Dose Rates for Several Spent Nuclear Fuel Dry Storage System Designs. Washington, DC. ADAMS Accession No. ML19072A031. 2019.
ACI 349.3R-2018, Report on Evaluation and Repair of Existing Nuclear Safety-Related Concrete Structures. American Concrete Institute. 2018.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 21-4. [Non PROP] Clarify or correct the aging management review results with respect to whether Microbiological attack is considered a credible aging mechanism for the HSM concrete.
CoC renewal application Section 4.4 does not include or reference microbiological attack; however, Table A-3 Acceptance criteria states:
Absence of leaching and chemical attack, including microbiological chemical attack.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 22-4. [Non PROP] Provide aging management Tollgates for the HSM AMP for the concrete and non-concrete subcomponents or provide a justification that future reviews of inspection results and operating experience to confirm the effectiveness of the HSM AMP are not necessary.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 23-4. [Non PROP] Provide a description of the data collected in the HSM AMP for non-concrete subcomponent inspections and used for Monitoring and Trending. CoC renewal application Section 4.4.4 states the following:
For HSM concrete, crack maps are developed. Dimensioning is documented in photographic records by inclusion of a tape measure/crack gauge, a comparator, or both.
It is not clear if the HSM AMP requires any other data to be collected other than crack maps.
The application may reference to ACI 201.1R or ACI 349.3R Section 3.7.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 24-4. [Non PROP] Provide a technical justification for examining the basemat with a frequency of once every five years.
The staff note that NUREG-2214 Table 6-3 recommends annual general area walkdowns of all reinforced concrete structures that includes 100 percent of readily accessible surfaces (or a justified coverage) and 100 percent of normally inaccessible surfaces (or a justified coverage) of a subset of the reinforced concrete structures within the scope of renewal. A minimum of two of the same structures (i.e., same design bases) are evaluated at the minimum inspection frequency.
The staff also note that ACI 349.3R (ACI 2018) Chapter 6Evaluation Frequency states:
The frequency at which periodic evaluations are conducted using the evaluation procedure should be defined by the owner based on need.
Evaluation frequency should be based on the aggressiveness of environmental conditions and physical conditions of the plant structures.
The established frequencies should also ensure that any age-related degradation is detected at an early stage of degradation and appropriate mitigative actions can be implemented.
Reference ACI 349.3R-2018, Report on Evaluation and Repair of Existing Nuclear Safety-Related Concrete Structures. American Concrete Institute. 2018.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 25-4. [Non PROP] Provide a description of the data collected in the Basemat AMP for concrete inspections and used for Monitoring and Trending. CoC renewal application Section 4.5.4 states the following:
For basemat concrete, crack maps are developed. Dimensioning is documented in photographic records by inclusion of a tape measure/crack gauge, a comparator, or both.
It is not clear if the Basemat AMP requires any other data to be collected other than crack maps.
The application may reference to ACI 201.1R or ACI 349.3R Section 3.7 This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 26-4. [Non PROP] Clarify the scope of the Basemat AMP. CoC renewal application Section
4.5.7 states
Extent of condition investigation per the licensees corrective action program may cause additional inspections through means of a different method, increased inspection frequency, and/or expanded inspection sample size.
It is unclear how an expanded inspection sample size is possible if the entire accessible portions of the basemat are included in the inspection.
This information is needed to determined compliance with 10 CFR 72.240(c).
RAI 27-4. [Non PROP] Provide aging management Tollgates for the Basemat AMP for the concrete and non-concrete subcomponents or provide a justification that future reviews of
inspection results and operating experience to confirm the effectiveness of the Basemat AMP are not necessary.
This information is needed to determined compliance with 10 CFR 72.240(c).