ML25342A103
| ML25342A103 | |
| Person / Time | |
|---|---|
| Site: | Holtec |
| Issue date: | 12/19/2025 |
| From: | Shana Helton Division of Fuel Management |
| To: | Fleming J Holtec |
| References | |
| EAF-NMSS-2025-0102 IR 2025201 | |
| Download: ML25342A103 (0) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 EAF-NMSS-2025-0102 Ms. Jean Fleming Vice President of Licensing, Regulatory and Probabilistic Safety Analysis Holtec International Krishna P. Singh Technology Campus 1 Holtec Boulevard Camden, NJ 08104
SUBJECT:
HOLTEC INTERNATIONAL, INC. - FINAL SIGNIFICANCE DETERMINATION LETTER AND NOTICE OF VIOLATION; U.S. NUCLEAR REGULATORY COMMISSION INSPECTION REPORT 072001014/2025-201
Dear Ms. Jean Fleming:
This letter refers to the U.S. Nuclear Regulatory Commission (NRC)s final determination of the apparent violations as discussed with your staff on November 19, 2025. The purpose of the inspection was to assess the adequacy of Holtecs activities associated with the design and modifications of dry cask storage systems (DCSSs) to meet the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 72, Licensing Requirements for the Independent Storage of Spent Nuclear Fuel, High-level Radioactive Waste, and Reactor-related Greater Than Class C Waste, and select portions of 10 CFR Part 21, Reporting of Defects and Noncompliance.
Based on the information developed during the inspection, the NRC identified five apparent violations. Two of the five were being considered for escalated enforcement action in accordance with the NRC Enforcement Policy. The NRC provided details of the inspection in an NRC Inspection Report number 72-1014/2024-201, dated July 18, 2025. The inspection report can be found in the NRCs Agencywide Documents Access and Management System (ADAMS) under Accession No. ML25177C973. ADAMS is accessible from the NRC website at https://www.nrc.gov/reading-rm/adams.
Further, in the letter transmitting the inspection report, the NRC provided Holtec with the opportunity to address the apparent violations identified in the report by either: (1) attending a Pre-decisional Enforcement Conference (PEC), or (2) participating in an Alternative Dispute Resolution session before the NRC made a final enforcement decision.
On September 3, 2025, the NRC and Holtec convened for a PEC at the NRC Headquarters to discuss the apparent violations. Holtec provided information related to the apparent violation, as well as actions taken and planned by Holtec in response to the apparent violations. A summary of this meeting, which referenced the presentations from both the NRC and Holtec, was issued on December 15, 2025 (ML25272A269).
Following the PEC, Holtec submitted additional information for the NRC to consider as the NRC December 19, 2025
J. Fleming 2
staff proceeded with the final enforcement decision on September 9, 2025 (ML25253A288 and ML25253A289), and October 6, 2025 (ML25279A173). After considering all the information provided, the NRC staff determined that five violations of the NRC regulatory requirements occurred.
The two violations that were being considered for escalated enforcement were determined to be Severity Level IV significance and are cited in the enclosure, Notice of Violation (Notice). The remaining three violations were determined to be Severity Level IV non-cited violations consistent with Section 2.3.2 of the Enforcement Policy. The final significance determination of these violations and circumstances leading to these violations are included in the enclosed report.
The two cited violations contained in the Notice involved: (1) Violation of 10 CFR 72.48(c)(2)(vi),
Changes, tests, and experiments (CTEs), for a failure to obtain a CoC amendment pursuant to 10 CFR 72.244 prior to implementing a design change that created a possibility for a malfunction of the HI-STORM Flood/Wind (FW) version E1 and multi-purpose canister with a different result than any malfunction previously evaluated in the Final Safety Analysis Report (FSAR) (as updated); and, (2) Violation of 10 CFR 72.146, Design control, for a failure to subject design changes made on the HI-STORM FW overpack to design control measures commensurate with those applied to the original design. As a part of the final enforcement determination, the NRC made the decision to combine violations (1) and (2) as one problem since the violations were closely related. The other three apparent violations (3), (4), and (5) are being treated as non-cited violations consistent with section 2.3.2 of the NRC Enforcement policy.
The NRC noted that during the conference your staff described your position regarding the apparent violations (1) and (2) as follows: (A) that there was no safety significance, (B) there was no pathway for rainwater to enter the overpack and block the vents and that the unloaded overpacks may not be stored in the same manner as loaded overpacks, and (C) no water was found in loaded overpacks once site personnel removed drain plugs. However, in reviewing the additional information requested during the conference, the NRC staff noted that water had entered unloaded overpacks at two different sites with the overpack lid and inlet screens installed while on the pad. Another site had evidence of water leaving two loaded overpacks in small amounts but, as stated in the operating experience information provided, the amount of water was well below any level that would block airflow through the overpack.
The available information appears to support the possibility for water to enter and remain inside the FW overpacks without the ability to be identified, or until operators take actions to drain the water from the installed, not-important-to-safety drain line. Therefore, the NRC determined that this could lead to a different result than those described in the FSAR for normal, off normal, and accident storage conditions.
In evaluating the potential consequences and significance of the violations, the NRC considered whether the violation created a credible event that could potentially have significant actual consequences. The staff concluded that a rainfall event of sufficient duration and magnitude could obstruct, and fully block, the inlet vents leading to degradation of the heat removal capability with different results as presented in the FW DCSS FSAR for normal, off-normal, and accident conditions. The blocked airflow would potentially result in a significant temperature increase that would exceed the peak cladding temperature (PCT) of the fuel, and potentially cause a commensurate pressure increase that would challenge the confinement boundary of the multi-purpose canister (MPC). Although the FSAR and TS take credit for operators
J. Fleming 3
identifying and correcting any visible obstruction of the inlet vents, as mentioned above, internal flooding cannot be observed from the outside of the overpack based on the new configuration.
However, the NRC determined that if internal flooding of the overpack were to occur, some water would likely evaporate. The NRC noted that Holtec did not analyze the rainfall event for the new vent design, and therefore the amount of water that may be collected in a loaded overpack, and how much evaporation may occur, is uncertain. NRC assessed the severity of this problem using a risk-informed approach crediting evaporation for loaded casks and sites reducing heat load limits less than the maximum allowed by the technical specifications, as both evaporation and loading at lower heat loads maintains fuel below the PCT and MPC pressure within limits. Therefore, the NRC concluded that the cited violations were of low safety significance and assigned Severity Level IV in accordance with the NRC Enforcement Policy and Manual. The current Enforcement Policy is included on the NRC's website at:
https://www.nrc.gov/about-nrc/regulatory/enforcement/enforce-pol.html.
You are required to respond to this letter and the enclosed Notice. Please follow the instructions specified in the enclosed Notice when preparing your response. If you have additional information that you believe the NRC should consider, you may provide it in your response to the Notice. The NRC will use your response, in part, to determine whether further enforcement action is necessary to ensure compliance with regulatory requirements. In addition, we will follow up on your corrective actions during a future NRC inspection and will consider an increase in the design inspection frequency. Any decision on increasing the inspection frequency will be communicated to you, along with the basis for the decision. If the NRC decides to increase the routine inspection frequency, it will be performed accordance with Inspection Manual Chapter 2690, Inspection Program for Storage of Spent Reactor Fuel and Reactor-Related Greater than Class C Waste at Independent Spent Fuel Storage Installations and for 10 CFR Part 71 Transportation Packagings.
In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter, its enclosure, and your response, if any, will be made available electronically for public inspection in the NRC Public Document Room and in ADAMS, accessible from the NRC website at http://www.nrc.gov/reading-rm/adams.html. To the extent possible, your response should not include any personal privacy, proprietary, or safeguards information so that it can be made available to the Public without redaction. If personal privacy or proprietary information is necessary to provide an acceptable response, please provide a bracketed copy of your response that identifies the information that should be protected and a redacted copy of your response that deletes such information. If you request withholding of such information, you must specifically identify the portions of your response that you seek to have withheld and provide in detail the bases for your claim of withholding (e.g., explain why the disclosure of information will create an unwarranted invasion of personal privacy or provide the information required by 10 CFR 2.390(b) to support a request for withholding confidential commercial or financial information).
J. Fleming 4
If you have any questions concerning this matter, please contact Gerond George at (301) 415-3882 or email (Gerond.George@nrc.gov).
Sincerely, Shana Helton, Director Division of Fuel Management Office of Nuclear Material Safety and Safeguards Docket No. 72-1014
Enclosures:
- 2. Inspection Report 07201014/2025201 Signed by Helton, Shana on 12/19/25
ML25342A103 OFFICE NMSS/DFM NMSS/DFM NMSS/MSST NMSS/DFM NAME ARowe MDavis MBurgess GGeorge DATE 12/9/2025 12/11/2025 12/11/2025 12/11/2025 OFFICE OE/EB OGC NMSS/DFM NAME JPeralta SKirkwood SHelton DATE 12/15/2025 12/17/2025 12/19/2025 NOTICE OF VIOLATION Holtec International Docket No.: 72-1014 Camden, NJ EAF-NMSS-2025-0102 During an NRC inspection conducted on October 21 - 24, 2024, violations of NRC requirements were identified. In accordance with the NRC Enforcement Policy, the violations are listed below:
(1) 10 CFR 72.48(c)(2)(vi), Changes, tests, and experiments (CTEs), requires, in part, that a certificate holder shall obtain a certificate of compliance (CoC) amendment pursuant to 10 CFR 72.244, prior to implementing a proposed change, test, or experiment if the change, test, or experiment would create a possibility for a malfunction of a structure, system, or component (SSC) important to safety (ITS) with a different result than any previously evaluated in the final safety analysis report (FSAR) (as updated).
Contrary to the above, from September 2021 to present, Holtec International, Inc.
(Holtec) failed to obtain a CoC amendment pursuant to 10 CFR 72.244, prior to implementing a proposed change that created a possibility for a malfunction of an SSC ITS with a different result than any previously evaluated in the FSAR as updated. Specifically, Holtec failed to obtain a CoC amendment pursuant to 10 CFR 72.244, prior to implementing a design change that raised the air inlet vents from the bottom of the HI-STORM Flood/Wind (FW) overpack to above ground positions, which created a low point for water to collect in the overpack after normal rainfall.
When Holtec made this change and evaluated the design change with their design control change process, Holtec failed to recognize that this created a possibility for all air inlet vents to become blocked for a period greater than what was analyzed in the FSAR when rainwater entered the overpack. The HI-STORM FW FSAR sections 4.6.2.4 (100 percent [%] Blockage of the Air Inlets), 12.2.13 (100% Blockage of Air inlets), and table 12.2.1, Accident Events and Their Probability of Occurrence, had considered an extended period where all air inlet vents are blocked and that this was a non-credible event, respectively. However, this design change created a possibility for all air inlet vents to become blocked for a period greater than what was analyzed in the FSAR and made, what was deemed as a non-credible event, a credible event that would create a possibility for a malfunction of the HI-STORM FW overpack and multi-purpose canister (MPC) with a different result than any previously evaluated in the FSAR, as updated. The malfunction of the HI-STORM FW overpack could result in fuel within the MPC exceeding temperature limits and the MPC exceeding pressure limits during normal operation.
(2) 10 CFR 72.146 (c), Design Control, requires, in part, that the certificate holder shall subject design changes to design control measures commensurate with those applied to the original design.
Contrary to the above, from September 2021 to present, Holtec failed to subject a design change made to the HI-STORM FW overpack to design control measures commensurate with those applied to the original design. Specifically, Holtec made a change to the original HI-STORM FW overpack design using their design change
2 control process to raise the air inlet vents from the bottom of the overpack to above ground positions. However, Holtec failed to identify that rainwater that enters the overpack can remain trapped inside of the overpack blocking the air inlets for an extended period. The trapped rainwater could result in the fuel exceeding peak cladding temperatures and increase the internal pressure limits in the MPC if there is no operator action taken to drain the water. This design change also does not allow operators to visually observe the trapped rainwater from the outside due to the configuration of this new design making this a more active versus a passive design function. Furthermore, this condition could create the possibility of an unanalyzed condition where an event considered non-credible in the FSAR is now a credible event.
This is a Severity Level IV problem (Section 6.1.d.2).
Pursuant to the provisions of 10 CFR 2.201, Holtec is hereby required to submit a written statement or explanation for this Notice of Violation (Notice or NOV) to the NRC, ATTN:
Document Control Desk, Washington, DC 20555-0001, with a copy to Shana Helton, Division Director, Division of Fuel Management, Office of Nuclear Material Safety and Safeguards, Two White Flint North, 11545 Rockville Pike, Rockville, MD 20852-2738, within 30 days of the date of the letter transmitting this Notice. This reply should be clearly marked as a "Reply to a Notice of Violation; EAF-NMSS-2025-0102 and should include for each violation: (1) the reason for the violation, or, if contested, the basis for disputing the violation or severity level; (2) the corrective steps that have been taken and the results achieved; (3) the corrective steps that will be taken; and (4) the date when full compliance will be achieved. Your response may reference or include previous docketed correspondence, if the correspondence adequately addresses the required response. If an adequate reply is not received within the time specified in this Notice, an order or a Demand for Information may be issued requiring information as to why the license should not be modified, suspended, or revoked, or why such other action as may be proper should not be taken. Where good cause is shown, consideration will be given to extending the response time.
If you contest this enforcement action, you should also provide a copy of your response, with the basis for your denial, to the Director, Office of Enforcement, United States Nuclear Regulatory Commission, Washington, DC 20555-0001.
Your response will be made available electronically for public inspection in the NRC Public Document Room or in the NRCs Agencywide Documents Access and Management System ADAMS, accessible from the NRC website at http://www.nrc.gov/reading-rm/adams.html. To the extent possible, your response should not include any personal privacy, proprietary, classified, or safeguards information so that it can be made available to the public without redaction. If personal privacy or proprietary information is necessary to provide an acceptable response, then please provide a bracketed copy of your response that identifies the information that should be protected and a redacted copy of your response that deletes such information. If you request withholding of such material, you must specifically identify the portions of your response that you seek to have withheld and provide in detail the bases for your claim of withholding (e.g.,
explain why the disclosure of information will create an unwarranted invasion of personal privacy or provide the information required by 10 CFR 2.390(b) to support a request for withholding confidential commercial or financial information). If safeguards information is necessary to provide an acceptable response, please provide the level of protection described in 10 CFR 73.21. If Classified Information is necessary to provide an acceptable response, please provide the level of protection described in 10 CFR Part 95.
3 In accordance with 10 CFR 19.11, you may be required to post this Notice within two working days of receipt.
Dated this 19th day of December 2025.
U.S. NUCLEAR REGULATORY COMMISSION Inspection Report Docket Number:
07201014 Report Number:
07201014/2025201 Enterprise Identifier:
I-2025-201-0041 Licensee:
Holtec International Facility:
Holtec International Location:
Camden, New Jersey Inspection Dates:
August 04, 2025 to November 19, 2025 Inspectors:
M. Davis, Senior Transportation & Storage Safety Inspector A. Rowe, Transportation & Storage Safety Inspector T. Terry, Project Manager Approved By:
Gerond George, Chief Inspection and Oversight Branch Division of Fuel Management
2
SUMMARY
On October 21, 2024, through October 25, 2024, the U.S. Nuclear Regulatory Commission (NRC) conducted an announced onsite team inspection at the Holtec International, Inc. (Holtec) corporate office in Camden, New Jersey. Based on the information developed during the inspection, the NRC had identified five apparent violations of which two of the five were being considered for escalated enforcement action in accordance with the NRC Enforcement Policy.
The NRC provided details of the inspection in an NRC Inspection Report number 72-1014/2024-201, dated July 18, 2025. On September 3, 2025, the NRC and Holtec convened a pre-decisional enforcement conference (PEC) at the NRC Headquarters to discuss the apparent violations. The final determination of the apparent violations was communicated to the licensee on November 19, 2025.
List of Findings and Violations Failure to Obtain a certificate of compliance (CoC) Amendment Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) Section 72.244 Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NOV 07201014/2024201-01 Closed EAF-NMSS-2025-0102 Not Applicable 60851 The team identified a Severity Level IV Violation of 10 CFR 72.48(c)(2)(vi), Changes, tests, and experiments (CTEs), which requires, in part, that a certificate holder shall obtain a CoC amendment pursuant to 10 CFR 72.244, prior to implementing a proposed change, test, or experiment if the change, test, or experiment would create a possibility for a malfunction of a structure, system, or component (SSC) important to safety (ITS) with a different result than any previously evaluated in the FSAR (as updated).
Failure to Establish Adequate Design Control Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NOV 07201014/2024201-02 Closed EAF-NMSS-2025-0102 Not Applicable 60851 The team identified a Severity Level IV Violation of 10 CFR 72.146 (c), Design Control, requires, in part, that the certificate holder shall subject design changes to design control measures commensurate with those applied to the original design.
Failure to Include a Written Evaluation Which Provided the Bases for the Determination that a COC Amendment Pursuant to Paragraph (c)(2)
Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 07201014/2024201-03 Closed EAF-NMSS-2025-0102 Not Applicable 60851
3 Failure to Include a Written Evaluation Which Provided the Bases for the Determination that a COC Amendment Pursuant to Paragraph (c)(2)
Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 07201014/2024201-04 Closed EAF-NMSS-2025-0102 Not Applicable 60851 The team identified a Severity Level IV non-cited violation of 10 CFR 72.48(d)(1) which requires, in part, that the certificate holder shall maintain records of changes in the facility or spent fuel storage cask design, of changes in procedures, and of tests and experiments made pursuant to paragraph (c) of this section. These records must include a written evaluation which provides the bases for the determination that the change, test, or experiment does not require a license or CoC amendment pursuant to paragraph (c)(2) of this section.
Failure to Promptly Identify and Correct a Condition Adverse Quality Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 07201014/2024201-05 Closed EAF-NMSS-2025-0102 Not Applicable 60851 The team identified a Severity Level IV non-cited violation of 10 CFR 72.172 Corrective action which requires, in part, that the certificate holder shall establish measures to ensure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances, are promptly identified and corrected. In the case of a significant condition identified as adverse to quality, the measures must ensure that the cause of the condition is determined, and corrective action is taken to preclude repetition. The identification of the significant condition adverse to quality, the cause of the condition, and the corrective action taken must be documented and reported to appropriate levels of management Additional Tracking Items None.
The team identified a Severity Level IV non-cited violation of 10 CFR 72.48(d)(1), Changes, tests, and experiments requires, in part, that the certificate holder shall maintain records of changes in the facility or spent fuel storage cask design, of changes in procedures, and of tests and experiments made pursuant to paragraph (c) of this section. These records must include a written evaluation which provides the bases for the determination that the change, test, or experiment does not require a license or CoC amendment pursuant to paragraph (c)(2) of this section.
4 INSPECTION SCOPES Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2690, Inspection Program for Storage of Spent Reactor Fuel and Reactor-Related Greater-Than-Class C Waste at Independent Spent Fuel Storage Installations and for 10 CFR Part 71 Transportation Packagings. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
INSPECTION RESULTS Failure to Obtain a COC Amendment Pursuant to 10 CFR 72.244 Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NOV 07201014/2024201-01 Closed EAF-NMSS-2025-0102 Not Applicable 60851 The team identified a Severity Level IV Violation of 10 CFR 72.48(c)(2)(vi), Changes, tests, and experiments (CTEs), which requires, in part, that a certificate holder shall obtain a CoC amendment pursuant to 10 CFR 72.244, prior to implementing a proposed change, test, or experiment if the change, test, or experiment would create a possibility for a malfunction of a SSC ITS with a different result than any previously evaluated in the FSAR (as updated).
==
Description:==
The team reviewed a design change associated with the introduction of a new overpack version for the HI-STORM Flood/Wind (FW) storage system. The HI-STORM FW storage system has two major storage components: the multi-purpose canister (MPC) and the storage overpack. The MPC is a welded and bolted pressure vessel that maintains the confinement boundary for the stored spent nuclear fuel assemblies. The HI-STORM FW storage overpack provides structural protection, cooling, and radiological shielding for the MPC while stored on the independent spent fuel storage installation (ISFSI) pad. Holtec made a design change to the standard overpack design of the HI-STORM FW storage system that elevated the air inlet vents from the bottom of the circumference of the overpack to raised positions. For this inspection activity, the team reviewed the design change from the standard HI-STORM FW overpack to version E1, but identified that Holtec made similar changes to other overpacks and designated those changes as versions E and F.
As part of this design change review, the team reviewed the 10 CFR 72.48 evaluation number (No.) 1541 revisions 0 and 1, specific sections of the HI-STORM FW FSAR revisions 7, 8, and 9, the HI-STORM FW technical specifications (TSs), engineering change order (ECO) No. 5018-130 revisions 0 and 1, and the NRCs safety evaluation report (SER) for the HI-STORM FW storage system. As described above, the design change raised the inlet vents of the HI-STORM FW overpack above ground level to preclude floodwater ingress into the cask system. Changing the height of the inlet vents created a potential for water to remain trapped in the lower portion of the overpack after a normal rainfall occurrence while in storage. If enough water enters the overpack, it could block airflow to the air inlet vents and result in an adverse thermal effect on the fuel assemblies and the MPC.
5 The team noted that Holtec had performed evaluations of these scenarios in sections 4.6.1.3 (Partial Blockage of Air Inlets/Outlets), 4.6.2.4 (100 percent [%] Blockage of the Air Inlets),
and 12.2.13 (100% Blockage of Air inlets) of the HI-STORM FW FSAR. Additionally, the FSAR contained the thermal impact results presented in the HI-STORM FW system tables 4.6.5, 4.6.7, and 12.2.1 in the FSAR.
Additionally, as provided in the TS bases contained in the FSAR, the TS assumed that under normal storage conditions the inlet and outlet air ducts are unobstructed and have full air flow (i.e., maximum heat transfer for the given ambient temperature). The team noted rainwater could enter through either the inlet or outlet vents, and it would be undetectable when performing the daily TS surveillance to ensure vents remain unblocked. The water would not be seen from the outside because the water would gather in low points inside of the overpack. The team had gathered operating experience from NRC inspections that indicated rainwater would enter the HI-STORM FW overpack internal cavity, but the rainwater would not immediately exit the cavity through the inlet vents as it would with the original configuration.
The team also noted that the 100% blockage of the air inlet vents may exceed the 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br /> stated in section 4.6.2.4 of the FSAR analysis, if the water trapped inside the overpack goes undetected because it cannot be seen from the outside. The team noted that additional operator actions would be needed to remove the water from inside the overpack if detected. If undetected, then for normal storage conditions this would lead to an off-normal and accident condition, essentially changing the frequency category from normal to off-normal or accident conditions. The team noted that this was similar to an example in section 6.1 of NEI 12-04, which states, in part, that a change from one frequency category to a more frequent category is a change that results in more than a minimal increase in the frequency of occurrence of an accident (see Criterion 1 of the 10 CFR 72.48 evaluation criteria). However, Holtec did not identify the direct and indirect impacts in their 10 CFR 72.48 evaluation nor as a part of their ECO.
Furthermore, the HI-STORM FW FSAR table 12.2.1, Accident Events and Their Probability of Occurrence, had considered this a non-credible event. The team noted that operating experience showed the presence of water in the overpacks at several different sites related to this design change. Subsequently, this design change increased the likelihood of a malfunction, previously thought to be non-credible, to a credible malfunction with a different result (Criterion 6 of 10 CFR 72.48 evaluation criteria). The team reviewed the industry endorsed guidance document NEI-12-04, revision 2 to gain insights on what changes are permissible without prior NRC review and approval that could create a new result from a malfunction. The team noted that section 6.6 of NEI 12-04, stated, in part, that a proposed change or activity that increases the likelihood of a malfunction previously thought to be incredible to the point where it becomes as likely as the malfunctions assumed in the updated FSAR, could create a possible malfunction with a different result.
Holtec implemented compensatory measures in revision 1 of the ECO and 10 CFR 72.48 evaluation to remove the plugs from the drain lines if the overpack has a separate drain line near the baseplate of the overpack. However, the team noted that these drain lines could still get clogged, so removing the plugs mitigates but doesnt eliminate the issue. Furthermore, this would need an active operator action to maintain what should be a passive cooling system. The team determined that Holtec was required to seek prior NRC review and approval for this design change to the HI-STORM FW overpack because this change would
6 create a possibility for a malfunction of a SSC ITS with a different result than any previously evaluated in the FSAR (as updated).
Corrective Actions: Holtec implemented compensatory measures in revision 1 of the ECO and a 10 CFR 72.48 evaluation to remove the plugs from the drain lines, if the overpack has a separate drain line near the baseplate of the overpack.
Performance Assessment: Performance was assessed using the traditional enforcement process from the NRC Enforcement Policy.
Enforcement:
Severity: Using the NRC Enforcement Policy, the NRC determined that this Violation is Severity Level IV because that the Violation created the potential of more than minor safety or security consequences. (NRC Enforcement Policy, Section 6.1.d.2).
Violation: 10 CFR 72.48(c)(2)(vi), Changes, tests, and experiments (CTEs), requires, in part, that a certificate holder shall obtain a CoC amendment pursuant to 10 CFR 72.244, prior to implementing a proposed change, test, or experiment if the change, test, or experiment would create a possibility for a malfunction of a SSC ITS with a different result than any previously evaluated in the FSAR (as updated).
Contrary to the above, from September 2021 to present, Holtec failed to obtain a CoC amendment pursuant to 10 CFR 72.244, prior to implementing a proposed change that created a possibility for a malfunction of an SSC ITS with a different result than any previously evaluated in the FSAR as updated. Specifically, Holtec failed to obtain a CoC amendment pursuant to 10 CFR 72.244, prior to implementing a design change that raised the air inlet vents from the bottom of the HI-STORM FW overpack to above ground positions, which created a low point for water to collect in the overpack after normal rainfall. When Holtec made this change and evaluated the design change with their design control change process, Holtec failed to recognize that this created a possibility for all air inlet vents to become blocked for a period greater than what was analyzed in the FSAR when rainwater entered the overpack. The HI-STORM FW FSAR sections 4.6.2.4 (100% Blockage of the Air Inlets), 12.2.13 (100% Blockage of Air inlets), and table 12.2.1, Accident Events and Their Probability of Occurrence, had considered an extended period where all air inlet vents are blocked and that this was a non-credible event, respectively. However, this design change created a possibility for all air inlet vents to become blocked for a period greater than what was analyzed in the FSAR and made what was deemed as a non-credible event to a credible event that would create a possibility for a malfunction of the HI-STORM FW overpack and MPC with a different result than any previously evaluated in the FSAR as updated. The malfunction of the HI-STORM FW overpack could result in fuel within the MPC exceeding temperature limits and the MPC exceeding pressure limits during normal operation.
Enforcement Action: This violation is being treated as a cited violation, consistent with Section 2.3.3 of the Enforcement Policy.
7 Failure to Establish Adequate Design Control Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NOV 07201014/2024201-02 Closed EAF-NMSS-2025-0102 Not Applicable 60851 The team identified a Severity Level IV Violation of 10 CFR 72.146 (c), Design Control, requires, in part, that the certificate holder shall subject design changes to design control measures commensurate with those applied to the original design.
==
Description:==
The team reviewed a design change associated with the introduction of a new overpack version for the HI-STORM FW storage system. The HI-STORM FW storage system has two major storage components: the MPC and the storage overpack. The MPC is a welded and bolted pressure vessel that maintains the confinement boundary for the stored spent nuclear fuel assemblies. The HI-STORM FW storage overpack provides structural protection, cooling, and radiological shielding for the MPC while stored on the ISFSI pad.
Holtec made a design change to the standard overpack design of the HI-STORM FW storage system that elevated the air inlet vents from the bottom of the circumference of the overpack to raised positions. For this inspection activity, the team reviewed the design change from the standard HI-STORM FW overpack to version E1, but identified that Holtec made similar changes to other overpacks and designated those changes as versions E and F.
As part of this design change review, the team reviewed the 10 CFR 72.48 evaluation number (No.) 1541 revisions 0 and 1, specific sections of the HI-STORM FW FSAR revisions 7, 8, and 9, the HI-STORM FW TSs, ECO No. 5018-130 revisions 0 and 1, and the NRCs SER for the HI-STORM FW storage system. As described above, the design change raised the inlet vents of the HI-STORM FW overpack above ground level to preclude floodwater ingress into the cask system. Changing the height of the inlet vents created a potential for water to remain trapped in the lower portion of the overpack after a normal rainfall occurrence while in storage. If enough water enters the overpack it could block airflow to the air inlet vents and result in an adverse thermal effect on the fuel assemblies and the MPC.
The team noted that Holtec had performed evaluations of these scenarios in sections 4.6.1.3 (Partial Blockage of Air Inlets/Outlets), 4.6.2.4 (100% Blockage of the Air Inlets), and 12.2.13 (100% Blockage of Air Inlets) of the HI-STORM FW FSAR. Additionally, the FSAR contained the thermal impact results presented in the HI-STORM FW system tables 4.6.5, 4.6.7, and 12.2.1 in the FSAR.
Additionally, as provided in the TS bases contained in the FSAR, the TS assumed that under normal storage conditions the inlet and outlet air ducts are unobstructed and have full air flow (i.e., maximum heat transfer for the given ambient temperature). The team noted rainwater could enter through either the inlet or outlet vents, and it would be undetectable when performing the daily TS surveillance to ensure vents remain unblocked. The water would not be seen from the outside because the water would gather in low points inside of the overpack. The team had gathered operating experience from NRC inspections that indicated rainwater would enter the HI-STORM FW overpack internal cavity, but the rainwater would not immediately exit the cavity through the inlet vents as it would with the original configuration.
The team also noted that the 100% blockage of the air inlet vents may exceed the 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br />
8 stated in section 4.6.2.4 of the FSAR analysis, if the water trapped inside the overpack goes undetected because it cannot be seen from the outside. The team noted that additional operator actions would be needed to remove the water from inside the overpack if detected. If undetected, then for normal storage conditions this would lead to an off-normal and accident condition, essentially changing the frequency category from normal to off-normal or accident conditions. The team noted that this was like an example in section 6.1 of NEI 12-04, which states, in part, that a change from one frequency category to a more frequent category is clearly an example of a change that results in more than a minimal increase in the frequency of occurrence of an accident (see Criterion 1 of the 10 CFR 72.48 evaluation criteria).
However, Holtec did not identify the direct and indirect impacts in their 10 CFR 72.48 evaluation nor as a part of their ECO.
Furthermore, the HI-STORM FW FSAR table 12.2.1, Accident Events and Their Probability of Occurrence, had considered this a non-credible event. The team noted that operating experience showed the presence of water in the overpacks at several different sites related to this design change. Subsequently, this design change increases the likelihood of a malfunction previously thought to be non-credible to the point where it became a credible event with a different result (Criterion 6 of 10 CFR 72.48 evaluation criteria). The team had reviewed the industry endorsed guidance document NEI-12-04, revision 2 to gain insights on what changes are permissible without prior NRC review and approval that could create a new result from a malfunction. The team noted that section 6.6 of NEI 12-04, stated, in part, that a proposed change or activity that increases the likelihood of a malfunction previously thought to be incredible to the point where it becomes as likely as the malfunctions assumed in the updated FSAR, could create a possible malfunction with a different result.
Holtec implemented compensatory measures in revision 1 of the ECO and 10 CFR 72.48 evaluation to remove the plugs from the drain lines if the overpack has a separate drain line near the baseplate of the overpack. However, the team noted that these drain lines could still get clogged, so removing the plugs mitigates but doesnt eliminate the issue. Furthermore, this would need an active operator action to permanently substitute what should be a passive cooling system. The team determined that Holtec needed to seek prior NRC review and approval for this design change to the HI-STORM FW overpack because this change would create a possibility for a malfunction of a SSC ITS with a different result than any previously evaluated in the FSAR (as updated).
Performance Assessment: Performance was assessed using the traditional enforcement process from the NRC Enforcement Policy.
Severity: Using the NRC Enforcement Policy, the NRC determined that this violation is Severity Level IV because the Violation created the potential of more than minor safety or security consequences.
Violation: 10 CFR 72.146 (c), Design Control, requires, in part, that the certificate holder shall subject design changes to design control measures commensurate with those applied to the original design.
Contrary to the above, from September 2021 to present, Holtec failed to subject a design change made to the HI-STORM FW overpack to design control measures commensurate with those applied to the original design. Specifically, Holtec made a change to the original HI-STORM FW overpack design using their design change control process to raise the air inlet vents from the bottom of the overpack to above ground positions. However, Holtec failed to identify that rainwater that enters the overpack can remain trapped inside of the overpack
9 blocking the air inlets for an extended period. The trapped rainwater could result in the fuel exceeding peak cladding temperatures and increase the internal pressure limits in the MPC if there is no operator action taken to drain the water. This design change also does not allow operators to visually observe the trapped rainwater from the outside due to the configuration of this new design making this a more active versus a passive design function. Furthermore, this condition could create the possibility of an unanalyzed condition where an event considered non-credible in the FSAR is now a credible event.
Enforcement Action: This violation is being treated as a cited violation, consistent with Section 2.3.3 of the Enforcement Policy.
Failure to Include a Written Evaluation Which Provided the Bases for the Determination that a COC Amendment Pursuant to Paragraph (c)(2)
Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 07201014/2024201-03 Closed EAF-NMSS-2025-0102 Not Applicable 60851 The team identified a Severity Level IV non-cited violation of 10 CFR 72.48(d)(1), Changes, tests, and experiments requires, in part, that the certificate holder shall maintain records of changes in the facility or spent fuel storage cask design, of changes in procedures, and of tests and experiments made pursuant to paragraph (c) of this section. These records must include a written evaluation which provides the bases for the determination that the change, test, or experiment does not require a license or CoC amendment pursuant to paragraph (c)(2) of this section.
==
Description:==
The team assessed Holtecs 10 CFR 72.48 screening no. 1591 associated with a design change to allow movement of the lidless HI-STORM 100 (Version E and E1) overpack with loaded MPC configuration outside of the fuel handling building. The inspectors determined that this design change would have screened in for a full evaluation under Holtecs screening questions a. and c. since (1) the proposed activity could adversely affect the design function of the MPC and (2) there was no method of evaluation (MOE) used in supporting the updated FSAR analysis that demonstrates the intended design function will be accomplished under design basis conditions such as natural phenomena. Holtec initially screened the activity out of the 10 CFR 72.48 evaluation process. Holtec originally required a full evaluation but later revised the evaluation to just a screening. Holtec took credit for two MOEs in the FSAR and stated, that although different, both together bounded the activity (i.e., a combination of two tornado missile analysis), one with the vertical HI-STORM 100 Version E and E1 with the lid bolted on, and the other with HI-TRAC in the horizonal orientation with the MPC exposed (see FSAR-R23: subsections 3.48.2 and 3.II.4.4.2).
Performance Assessment: Performance was assessed using the traditional enforcement process from the NRC Enforcement Policy.
Enforcement:
Severity: Using the NRC Enforcement Policy, the NRC determined that this non-cited violation is Severity Level IV because the violation created the potential of more than minor safety or security consequences. (NRC Enforcement Policy, Section 6.1.d.2)
Violation: 10 CFR 72.48(d)(1), Changes, tests, and experiments requires, in part, that the certificate holder shall maintain records of changes in the facility or spent fuel storage cask
10 design, of changes in procedures, and of tests and experiments made pursuant to paragraph (c) of this section. These records must include a written evaluation which provides the bases for the determination that the change, test, or experiment does not require a license or CoC amendment pursuant to paragraph (c)(2) of this section.
Contrary to the above, as of May 2025, the certificate holder (Holtec) failed to maintain records of changes in the facility or spent fuel storage cask design, of changes in procedures, and of tests and experiments made pursuant to paragraph (c) of this section. The records did not include a written evaluation which provided the bases for the determination that the moving of the HI-STORM 100 overpack version E and E1 without a lid outside the fuel building does not require a license or CoC amendment pursuant to paragraph (c)(2) of this section. Specifically, Holtec stopped at their procedural 10 CFR 72.48 screening process step and did not perform a full evaluation. The inspectors determined that Holtec should have screened this design change for a full evaluation under Holtecs screening questions a. and c.
since (1) the proposed activity could adversely affect the design function of the MPC and (2) there was no method of evaluation used in supporting the updated FSAR analysis that demonstrates the intended design function will be accomplished under design basis conditions such as natural phenomena.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
Failure to Include a Written Evaluation Which Provided the Bases for the Determination that a COC Amendment Pursuant to Paragraph (c)(2)
Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 07201014/2024201-04 Closed EAF-NMSS-2025-0102 Not Applicable 60851 The team identified a Severity Level IV non-cited violation of 10 CFR 72.48(d)(1) which requires, in part, that the certificate holder shall maintain records of changes in the facility or spent fuel storage cask design, of changes in procedures, and of tests and experiments made pursuant to paragraph (c) of this section. These records must include a written evaluation which provides the bases for the determination that the change, test, or experiment does not require a license or CoC amendment pursuant to paragraph (c)(2) of this section.
==
Description:==
The team assessed Holtecs 10 CFR 72.48 evaluation no. 1516, revision 1, specific sections of the HI-STORM FW FSAR (HI-2114830) revisions 8 and 9, the HI-STORM FW TSs bases document, ECO No. 5018-126 revision 1 and the NRCs SER for the HI-STORM FW storage system for a design change associated with a new storage overpack and common lid. Holtec performed a full evaluation of the design change because Holtec used a different version of the finite element analysis (ANSYS) code thus impacting an element of the MOE used in establishing the design bases.
The team assessed the evaluation using the endorsed industry guidance document NEI 12-04, revision 2. Section 6.8.1 of NEI 12-04 provides guidance when changing one or more elements of the MOE. As stated in the 10 CFR 72.48 evaluation, the team noted that the analysis of the common lid used a different version of ANSYS (ANSYS 2020 R2 vs ANSYS 11). The NRC previously approved (ANSYS 11) for the standard HI-STORM FW lid. Holtec
11 performed a verification and validation (V&V) of the finite element analysis. However, Holtec did not reanalyze one or more representative cases using the revised software (ANSYS 2020 R2) to compare those cases with those in the FSAR to determine if the current results produced results that are conservative, non-conservative, or essentially the same, as the previous values in the FSAR for the overpack and common lid.
The team explained to Holtec that comparing one or more representative cases using the revised software to those cases in the FSAR to determine if the new MOE results produced conservative, non-conservative, or essentially the same, as the previous values in the FSAR is consistent with the NEI 12-04, revision 2 guidance document after Holtec performed the V&V of the software. Specifically, section 6.8.1, Guidance for Changing One or More Elements of a MOE, provides a similar example of a code version change and provides the steps necessary to determine whether prior NRC review and approval is required. Holtec did not complete all the steps described in the guidance document to compare those cases with those in the FSAR to determine if the current results produced results that are conservative, non-conservative, or essentially the same, as the previous values in the FSAR. The team assessed that Holtecs failure to compare representative cases with those in the FSAR to determine if the current results produced results that were conservative, non-conservative, or essentially the same, as the previous values in the FSAR was a violation of NRC requirements in 10 CFR 72.48(d)(1).
Performance Assessment: Performance was assessed using the traditional enforcement process from the NRC Enforcement Policy.
Enforcement:
Severity: Using the NRC Enforcement Policy, the NRC determined that this non-cited violation is Severity Level IV because the violation created the potential of more than minor safety or security consequences. (NRC Enforcement Policy, Section 6.1.d.2)
Violation: 10 CFR 72.48(d)(1) requires, in part, that the certificate holder shall maintain records of changes in the facility or spent fuel storage cask design, of changes in procedures, and of tests and experiments made pursuant to paragraph (c) of this section. These records must include a written evaluation which provides the bases for the determination that the change, test, or experiment does not require a license or CoC amendment pursuant to paragraph (c)(2) of this section.
Contrary to the above, as of May 2025, the certificate holder (Holtec) failed to maintain records of changes in the facility or spent fuel storage cask design, of changes in procedures, and of tests and experiments made pursuant to paragraph (c) of this section. The records did not include a written evaluation which provided the bases for the determination that the introduction of an alternative storage overpack for the HI-STORM FW Version F and common lid using an updated MOE does not require a license or CoC amendment pursuant to paragraph (c)(2) of this section. Specifically, Holtec used a different version of the ANYSYS finite element analysis (ANSYS 2020 R2 vs 11) for the new overpack and lid than what was previously approved for the standard HI-STORM FW (ANSYS 11). Holtec performed a V&V of the ANSYS 2020 R2 with favorable results. However, Holtec did not reanalyze one or more representative cases using the revised software (ANSYS 2020 R2) to compare those cases with those in the FSAR to determine if the current results produced results that are conservative, non-conservative, or essentially the same, as the previous values in the FSAR for the overpack and common lid. Since Holtec did not compare the results to those in the FSAR, the evaluation did not have an adequate written bases to determine if prior NRC review and approval was needed.
12 Enforcement Action: This violation is being treated as a non-cited violation, consistent with section 2.3.2 of the Enforcement Policy.
Failure to Promptly Identify and Correct a Condition Adverse Quality Cornerstone Severity Cross-Cutting Aspect Report Section Not Applicable Severity Level IV NCV 07201014/2024201-05 Closed EAF-NMSS-2025-0102 Not Applicable 60851 The team identified a Severity Level IV non-cited violation of 10 CFR 72.172 Corrective action which requires, in part, that the certificate holder shall establish measures to ensure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances, are promptly identified and corrected. In the case of a significant condition identified as adverse to quality, the measures must ensure that the cause of the condition is determined, and corrective action is taken to preclude repetition. The identification of the significant condition adverse to quality, the cause of the condition, and the corrective action taken must be documented and reported to appropriate levels of management.
==
Description:==
The team assessed that Holtec, generally, provided adequate corrective actions for the cited traditional enforcement violation (EA-23-44). The team verified that Holtec performed a root cause evaluation that focused on the causal factors, extent-of-condition, and extent-of-cause, as necessary. The team noted that Holtec updated several program documents and provided training to necessary personnel.
However, as a part of the corrective action review for this condition, the team identified that the Holtec position paper DS-331 used to determine the design basis criteria, used the incorrect value for the true ultimate strength of the Metamic-HT to determine the maximum stress intensity limit that established the design basis limits. Specifically, Holtec used the fracture stress of the material instead of the ultimate strength. The NRC discovered the wrong value while reviewing documents for the continuous basked shims enforcement issue and HI-STORM FW amendment request in December 2023. The team determined that Holtec failed to promptly identify and correct the deficiencies and nonconformances as this impacted several storage and transportation systems. The team assessed that this was a violation of NRC requirements 10 CFR 72.172, Corrective actions.
Performance Assessment: Performance was assessed using the traditional enforcement process from the NRC Enforcement Policy.
Enforcement:
Severity: Using the NRC Enforcement Policy, the NRC determined that this non-cited violation is Severity Level IV because the violation created the potential of more than minor safety or security consequences.
Violation: 10 CFR 72.172 Corrective action requires, in part, that the certificate holder shall establish measures to ensure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances, are promptly identified and corrected. In the case of a significant condition identified as adverse to quality, the measures must ensure that the cause of the condition is determined, and corrective action is taken to preclude repetition. The identification of the
13 significant condition adverse to quality, the cause of the condition, and the corrective action taken must be documented and reported to appropriate levels of management.
Contrary to the above, prior to October 22, 2024, the certificate holder (Holtec) failed to establish measures to ensure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances, are promptly identified and corrected. Specifically, Holtec failed to promptly identify and correct a quality issue (QI) for the Holtec position paper (DS-331) credited in the storage and transportation system design basis of the FSARs for the development of stress and strain curves. Holtec used the wrong value, which would place the systems in an unanalyzed state or outside their storage and transportation systems licensing basis. However, once identified during the EA-23-044 cited violation issue and HI-STORM FW amendment review in December 2023, Holtec failed to initiate a QI and correct the deficiencies and nonconformances.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
EXIT MEETINGS AND DEBRIEFS The inspectors verified no proprietary information was retained or documented in this report.
On November 19, 2025, the inspectors presented the final significance determination to K. Manzione, Director of Licensing, and other members of the licensee staff.