L-24-053, Independent Spent Fuel Storage Installation, Request for Specific Exemption from Certain Requirements of 10 CFR 72.212 and 10 CFR 72.214
| ML24058A180 | |
| Person / Time | |
|---|---|
| Site: | Perry, 07200069  |
| Issue date: | 02/27/2024 |
| From: | Penfield R Energy Harbor Nuclear Corp |
| To: | Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-24-053 | |
| Download: ML24058A180 (1) | |
Text
Energy Harbor Nuclear Corp.
Perry Nuclear Power Plant 10 Center Road Perry, Ohio 44081
Rod L. Pen field 440- 280- 5382 Site Vice President, P erry Nuclear
February 27, 2024 L-24-053 10 CFR 72
ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D C 20555-0001
Subject:
Perry Nuclear Power Plant, Unit No. 1 Docket No. 50-4 40, License No. NPF-58 Perry Nuclear Power Plant, Unit No. 1 Independent Spent Fuel Storage I nstallation Docket No. 72-69 Request for Specific Exemption from Certain Requirements of 10 CFR 72.212 and 10 CFR 72.214
On January 30, 2024, the Nuclear Regulatory Commission (NRC) issued a Notice of Violation to Holtec Internatio nal, Inc based on information developed during a routine fabrication inspection ( Accession No.: ML24016A190). The NRC staff identified that Holtec incorporated a design change regarding the honeycombed fuel basket (including the MPC 89 that incorporated the Continuous Basket Shim (CBS) basket design) per the 10 CFR 72.48 change proc ess. The 10 CFR 72. 48 evaluations performed by Holtec for the CBS basket design change made an incorrect determination, as the design change was r equired to be submitted as a C ertificate of Compliance (CoC) a mendment requiring prior NRC review and approval pursuant to 10 CFR 72.244.
On January 31, 20 24, the NRC issued a Safety Determination of a potential structural failure of the Holtec fuel basket with the CBS design variant during accident c onditions for the HI -STORM 100 AND HI-STORM FLOOD/WIND (FW) dr y cask storage systems (Accession No.: ML24018A085).
In response to the above, Energy Harbor Nuclear Corp. (EHNC) evaluat ed the impact on the Holtec dry cask storage systems used at the Perry Nuclear Power Plant (PNPP).
PNPP currently utilizes the HI-STORM FW System, specifically MPC-89 with the CBS variant, under CoC No. 72-1032, Ame ndment No. 5 for dry storage of spent nuclear fuel and the corresponding Revision 9 of the Holtec Final Safety Analysis Report (FSAR).
Currently, EHNC plans to load MP C-89CBS systems during the summer 2024 dry cask campaign and during future campaigns.
Perry Nuclear Power Plant L-24-053 Page 2
In accordance with 10 CFR 72.7, Specific Exemptions, EHNC is requesting an exemption from certain requirements in 10 CFR 7 2.212 and 10 CFR 72.214. The attachment to this letter provides the justification and rationale for the exemption request.
EHNC requests approval of this exemption by July 1, 2024, to support the upcoming summer 2024 dry cask loading campaign.
There are no regulatory commitments contain ed in this submittal. If there are any questions or if additional information is required, please contact Mr. Phil H. Lashley, Manager - Fleet Licensing at ( 330) 696-7208.
Sincerely,
Elliott*
Rod L. Penfieldod LPenfield
- Christoper M. Elliott signed as Rod Penfields Alternate
Atta chment: Request for Specific Exemption from Certain Requirements of 10 CFR 72.212 and 10 CFR 72.214
cc: NRC Region III Administrator NRC Resident Inspector NRR Project Manager Utility Radiological Safety Bo ard Attachment L-24-053
Request for Specific Exemption from Certain Requ irements of 10 CFR 72.212 and 10 CFR 72.214 Page 1 of 10
TABLE OF CONTENTS
I. DESCRIPTION
II. BACKGROUND
III. BASIS FOR APPROVAL OF EXEMPTION REQUEST
IV. TECHNICAL JUSTIFICATION
V. ENVIRONMENTAL CONSIDERATION
VI. CONCLUSION
VII. REFERENCES Attachment L-24-053 Page 2 of 10
I. Description
The Holtec International Inc., (Holtec) HI-STORM FW dry cask storage system is designed to hold, and store spent fuel assemblies for independent spent fuel storage installation (ISFSI) deployment. The system is listed in 10 CFR 72.214 as C ertificate of Compliance (CoC) Number 72-1032 (Reference 1). This system is used by Energy Harbor Nuclear Corp. (EHNC) at Perry Nuclear Power Plant (PNPP) in accordance with 10 CFR 72.210, General license issued.
Pursuant to 10 CFR 72.7, Specific Exemptions, EHNC requests an exemption from certain requirements of 1 0 CFR 72.212(a)(2), 10 CFR 72.212(b)(3), 10 CFR 72.212(b)(5)(i), 10 CFR 72.212(b)(11), and 10 CFR 72.214 for PNPP. Specifically, an exemption is requested to allow use of the Holtec 89 multi -purpose canisters (MPCs) with a Continuous Basket Shim ( MPC-89CBS) design variant. If approved, t he requested exempt ion will allow loading of MPC-89CBS canisters, as listed in Table 1.
The exemption is needed becaus e although Holtec originally performed a tip-over analysis with favorable results and subsequently implemented the CBS design variants under 10 CFR 72.48, the NRC issued Severity Level IV violations ( Reference
- 2) that indicated th at these design variants should have resulted in an amendment to the HI-STORM FW CoC No. 72-1032. Specifically, the tip-over analys is performed for the CBS design included changes to elements of a previously approved method of evaluation ( MOE) as well a s the use of new or different MOEs thus requiring prior NRC approval via an amendment, which is not expecte d to be approved prior to PNPPs upcoming loading campaign.
EHNC requests approval of this exemption request by July 1, 2024, to support the loading of the next MPC-89CBS canister scheduled for August 2024.
The technical justification supporting cont inued use of the MPC-89CBS is provided in the following sections.
Table 1: List of Affected Canisters Schedu led for Loading HI-STORM Serial MPC Serial Targeted Location Date Scheduled to Number Number on ISFSI Pad be Placed in Storage HI-STORM 0283 MPC 0371 Pad 3, location 2 8/16/24 HI-STORM 0284 MPC 0372 Pad 3, location 3 8/23/24
II. Background
PNPP currently utilizes the HI-STORM FW System under CoC No. 72-1032,
Amendment No. 5 and the corresponding Holtec FSAR Rev. 9, for dry storage of spent nuclear fuel in specific MPCs (that is, MPC-89CBS canis ters). All design Attachment L-24-053 Page 3 of 10
features and contents must fully meet the HI-STORM FW CoC requirements, including required MPC or spent fuel contents and t echnical specification loadin g requirements within the l imiting conditions for operations (LCOs), and the site must demonstrate that they meet all site-specific parameters per 10 CFR 72.212.
Holtec International is the designer and manufacturer of the HI-STORM FW system.
Holtec developed a variant of the design for the MPC -89 known as MPC-89CB S. The MPC-89CBS ba sket, like the previously certified MPC -89, is made of Metamic -HT, and has the same geometric dimensions and assembly configuration. Im provements implemented through the new variant pertain to the external shims, which are between the basket periphery and the M PC shell, and the elimination of the difficult to manufacture friction-stir-weld (FSW) seams joining the raw edges of the basket panels.
The CBS variant calls for longer panels of Metami c-HT. The projections of the Metamic panels provide an effect ive means to secure the shims to the basket using a set of stainless -steel fasteners. These fasteners do no t carry any primary loads, except for the dead weight of the s hims when the MPC is oriented vertically, which generates minimal str ess in the fasteners. The f asteners are made of Alloy X stainless material, which is a pre -approved material for the MPCs in the HI -STORM FW system.
Fixing the shim to the basket has the added benefit of improving the heat transfer path from the stored fue l to the external surf ace of the MPC.
Holtec originally performed a tip-over analysis with favorable results and subsequently implemented the CBS design var iants under 10 CFR 72.48. However, the NRC issued Severity Level IV violations (Reference 2) that indicated that these design variants should have resulted in an amendment to the HI -STORM FW CoC number 1032.
III. Basis for Approval of Exemption Request
In accordance with 10 CFR 72.7, the NRC may, upon application by an interested person or upon its own initiative, grant such ex emptions from the requirements of the regulations in this part as it determines authorized by law and will not endanger life or property or the common defense and security and are otherw ise in the public interest.
a) Authorized by Law This exemption would allow EHNC to load additional canisters of the MPC -89CBS design. The NRC issued 10 CFR 72.7 under the authority granted to it under Section 133 of the Nuclear Was te Policy Act of 1982, as amended, 42 U.S.C. § 10153. Section 72.7 allows the NRC to grant exemptions from the requirements of 10 CFR Part 72. Granting the proposed exemption will not endanger life or property, or the common d efense and security, and is ot herwise in the public interest. Therefore, the exemption is authori zed by law.
Attachment L-24-053 Page 4 of 10
b) Will not Endanger Life or Property or the Common Defense and Security The NRC has performed a s afety assessment (Reference 3) to evaluate the loading and storage of the MPC -89CBS va riant without an approved tip-over analysis. This evaluation (detailed below) assumed basket failure due to the tip-over event but concluded that the consequences of a basket failure have a very low safety significance provided the confinement boundary is maintained and the fuel is kept in a dry storage condition. As these conditions are demonstrated to be met during a tip-over event, the staff determined that there was no need to take an immediate action with respec t to loaded HI-STORM 100 and HI-STORM FW dry cask storage systems with the continuous basket s him (CBS) fuel basket designs. Based on the NRC saf ety assessment detailed below and summar ized here, the proposed exemption does not endanger life or property or the common defense and secur ity.
c) Otherwise in the Public Interest It is in the publics interest to grant an exemption, since dry storage places the fuel in an inherently safe, passive system. This exemption would allow the upcoming loading campaign to proceed on t ime to move fuel into the dry storage condition and maintain the ability to offload fuel from the reactor, thus allowing continued safe reactor operation.
IV. Technical Justification
The MPC-89CBS basket assembly features the same fuel storage cavity configuration as the certified standard MPC -89 configuration. The manner in which the inter-panel connectivity is established and by which t he aluminum shims are held in place outside the basket is improved. This improvement is made such that, the loose aluminum shims around the basket periphery used in the original MPC -89 design are repl aced with integrated aluminum shims that are mechanicall y fastened (bolted) to basket panel extensions that protrude into the annular region between t he basket and the enclosure vessel. The addition of these bolted shims eliminates the need for the FSW located in the external periphery of the Metamic -HT fuel basket.
All other fuel basket design characteristics are unchanged by using the CBS variant.
Regardless of their design, the primary design fun ctions of the basket shims are to facilitate heat transfer away from the fuel basket and spent fuel assemblies an d to provide lateral support of the fuel basket during the non -mechanistic tip over accident.
The primary design functions of the Metamic -HT fuel basket itself, regardless of shim configuration, are to provi de structural support of the fuel assemblies and p erform the criticality control design function for the system. The MPC enclosure vessel prov ides structural support of t he fuel basket, assisting in the heat transfer process, and acts as the confinement boundary for the system.
On January 31, 202 4, the NRC issued a Safety Determination of a potential structural failure of the Holtec fuel basket with the CBS design variant during accident conditions Attachment L-24-053 Page 5 of 10
for the HI -STORM 100 AND HI-STORM FLOOD/WIND (FW) dry cask storage s ystems (reference 3).
The results of this safety determination are addressed below for the critical parameters or basic nuclear safety criteria as identified within the 10 CFR 72.48 process of the Holtec HI-STORM 100 and HI -STORM 100 Flood/Wind (FW) dry cask storage system with the CBS design variant.
Thermal The staff used the structural assessment discussed below to confirm there was no loss of confinement integrity and considered the thermal i mpacts of a postulated non-mechanistic tip-over accident. The staff considered fuel debris that might cause hot spots near the bottom of the MPC (on its side from a postulated tip-over). The staff noted that there might be some local increas e in temperatures, but no temperatures that would challenge th e MPC confinement based on its stainless -steel material. The thermal review conclude d,... the containment will remain intact and therefore the non-mechanistic tip-over accident condition does not result in significant safety consequences for the HI-STORM 100 and HI-STORM FW storage systems.
Structural and Confinement The hypothetical ti p-over accident is the most significant challenge of th e structural performance of the basket. The primary safety function is to prevent a criticality event, and as stated below, the criticality assessment determined no safety concerns under a hypothetical tip-over event with the assumption of basket failure.
The staff assessment (Reference 3 ) concluded that the MPC, which is the confinement boundary, maintains its stru ctural integrity during a tip-over event and therefore no water can enter the interior of the MPC during accident conditions. The staff also a cknowledge d that, consistent with the FSAR, there i s no requirement to demonstrate st ructural integrity of the cladding. Retrievability requirements continue to be met since, as stated above, the MPC maintains its integrity.
The staff also considered natu ral phenomena hazards (NPH) and concluded, the structural failure of the fuel baskets during these NPH accide nt conditions is unlikely. However, even if a basket failure occurs, the criticality ev aluation below demonstrates that the fuel will be main tained subcritical. Therefore, the staff concludes that the NPH accident conditions do not result in si gnificant safety consequences for the HI -STORM 100 and HI-STORM FW storage systems with the CBS fuel basket designs, (Referen ce 3).
Finally, the structural assessment considered the handling operations for the dry cask storage systems. The system is either handled with single failure proof devices where a drop is considered non-credible or held to a l ift height that has been demonstrated to be acceptable. The NRC concluded that... a similar conclusion to Attachment L-24-053 Page 6 of 10
that for the non-mechanistic tip-over can be made for dry ca sk handling accident conditions. The MPC confinement boundary maintains its structural integrity and no water can enter the interior of the MPC. Should the fuel basket fail to main tain its structural integrity during stack -up the fuel will be maintained in a subcritical condition, (Reference 3).
Shielding and Criticality In Reference 3, the staff assessed the potential for a criticality i ncident under a complete failure of the bask et, which could resul t in basket material and f uel debris at the bottom of the MPC. The staff relied on documented studies related to the enrichment of uranium needed to achieve criticality in an unmoderated, unr eflected environment. The allowable contents have enrichment lim its well below that in the studies and would also sti ll have the neutron absorbing material present. Therefore, the staff concluded there is no criticality safety concern for the CBS bask et variants for both the HI -STORM 100 and FW casks under the assumption of fuel basket failure.
As docum ented in Ref erence 3, the staff reviewed the shielding impact and concluded, as the damage is localized and the vast majority of the shielding material remains intact, the effect on the dose at the site boundar y is negligible.
Therefore, the site boun dary doses f or the loaded HI-STORM FW overpack for accident conditions are equiv alent to the normal condition doses, which meet the Title 10 of the Code of Federal Regulations (10 CFR) Section 72.106 radiation dose limits.
Radiation Protection As there is no adverse eff ect on the shielding or confinement functions, there is no effect on occupational or public exposures as a result of this off -normal event.
Materials There is no change in the material s used in the CBS variant of the basket compared to the original des ign of the MPC and basket. Therefore, there is no new material related safety concern.
Safety Conclusion The above analysis demonstrat es that structural failure of the CBS basket resulting from a tip-over event does not endanger life or property or the c ommon defense and security. As su ch the safety significance of not having an approved tip-over analysis, demonstrating the structural integrity of the CBS design during the postulated tip-over event, is bounded by the analysis assuming structural basket fa ilu re.
V. Environmental Consideration
EHNC evaluated the environmental impacts of the proposed exemption request based on the criteria for categorical exclusion under 10 CFR 51.22(c)(25). Based on the staff Attachment L-24-053 Page 7 of 10
assessment conclusions as discussed above, the environmental impacts are evaluated below:
(i) No significant hazards consideration.
EHNC has evaluated the proposed e xemption to determine whether a significant hazards consideration is involved by focusing on the three standards set forth in 10 CFR 50.92(c ) as discussed below. The no significant hazards consideration is being performed in accordance with 10 CFR 50.92, insofar as 10 CFR 72 does not establish separate criteria.
- 1. Does the proposed ex emption involve a significant increase in the probability or c onsequences of an accident previously evaluated?
Response: No
The staffs assessment conservatively assumes that the fuel basket fails under the non-mechanistic tip -over load case. However, the multi-purpose canister (MPC) confinement boundary is maintai ned; therefore, no fuel is released from the MPC, and no water is able to enter the interior of the MPC during accide nt conditions. The proposed exemption has no effect on facility structures, systems, and components (SSCs) and no effect on the capability of any facility SSC to perform its design function.
Since the MPC will continue to perform the intended safety func tion even with a postulated basket fail ure the proposed exemption does not involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2. Does the proposed exemption create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No
The proposed exemption does not involve a physical alteration of the facility. The proposed exem ption will not physically change any SSCs involvedin the mitigation of any accidents. Thus, no new initiators or precursors of a new or different kind of accident are created. Furthermor e, the proposed exem ption does not create the possibility of a new accident as a result of new failure modes associated with any equipment or personnel failures. No changes are being made to setpoints whic h initiate protective or mitigative actions, and no new failur e modes are being introduced.
Attachment L-24-053 Page 8 of 10
Therefore, the proposed exemption does not c reate the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. Does the proposed exemption involve a significant reduction in a margin of safety?
Response: No
The proposed exem ption does not impact facility operation or any SSC that is relied upon for accident mitigation. The staff assessment concluded that the MPC, which is the conf inement boundary, maintains its structural integrity during a postulated tip-over event and th e consequences of a basket failure is of very low safety significance provided the confinement boundary is maintained and the fuel is kept in a dry storage co ndition.
Therefore, the proposed exemption does not involve a significant reduction in margin o f safety.
(ii) No significant change in the types or significant increase in the amounts of any effluents that may be released offsite.
There are no changes in the types, characteristics, or quantities of effluents discharged to the environment associated w ith the proposed exemption. There are no materials or chemicals introduced into the facility that could affect the characteristics or types of effluents released offsite. In addition, the method of operation of waste processing systems will not be affected b y the exemption.
The proposed exemption will not result in changes to the design basis requirements of SSCs that function to limit or monitor the release of effluents.
Therefore, the proposed exemption will result in no significant change to the types or significant increase in the amounts of any effluents that may be released offsite.
(iii) No significant increase in individual or cumulative public or occupational radiation exposure.
The proposed exemption does not involve any physical alterations to the facility configuration or a ny changes to the operation of the facility that could lead to a significant increase in individual or cumulative occupational radiation exposure.
Thus, the exemption request would provide a benefit to site personnel and to the health and safety of the public without a reduction in safety margin. The proposed exemptio n meets the NRC regulatory limits and does not alter these requirements.
Attachment L-24-053 Page 9 of 10
(iv) No significant construction impacts.
No construction activities are associated with the proposed exemption.
(v) No significant increase in the potential for or consequences from radiological accidents.
See the no significant hazards considerations discussion in I tem (i)1 above.
(vi) The requirements from which an exemption is sought involve:
(A) Recordkeeping requirements; (B) Reporting requirements; ( C) Inspection or surveillance requirements; (D) Equipment servicing or maintenance scheduling requirement s; (E) Education, training, experience, qualification, requalification or other employment suitability requirements; (F) Safeguard plans, and materials control and accounting inventory scheduling requirements ; (G) Scheduling requirements; (H) Surety, insurance or indemnity requirements; or (I) Other requirements of an administrative, managerial, or organizational nature.
The proposed exemption does not meet subparagraph (vi) since it does not involve any of the requirements listed.
While the proposed exemption does not meet the eligibility crit erion for categorical exclusion set forth in 10 CFR 5 1.22(c)(25), there a re no significant environmental impacts associated with the proposed action. The proposed exemption does not:
- Increase the probability or consequences of accidents (see no s ignificant hazards consideration provide d in Item (i)1 above);
- Change the types of effluents released offsite;
- Increase the occupational or public radiation exposure;
- Involve any construction or other ground disturbing activities;
- Change the physical aspects of the dry or wet fuel storage features at the facility;
- Have any impacts on aquatic or terrestrial habitats in the vicinity of PNPP;
- Have any impacts on threatened, en dangered, or protected s pecies; and
- Have the potential to cause effects on historic or cultural properties, assuming such properties are present at the PNPP site.
Based on the above, EHNC concludes that the proposed exemption presents no significant hazards consideration and will not haveany environmental impacts.
Attachment L-24-053 Page 10 of 10
VI. Conclusion
As the safety assessment and environmental review above demonstrate, the HI-STORM FW system with the MPC-89CBS canister without an approved tip-over analysis continues to be c apable of performi ng required safety functions and is capable of mitigating the effects of design basis accidents and therefor e does not present a threat to public or environmental safety.
EHNC has reviewed the requirements in 10 CFR 72 and determined that an exemption to certain requirements in 72.2 12 and 72.214 are necessary. This exemption request would allow future loading of MPC -89CBS canisters, as listed in Table 1.
VII. References
1 HI-STORM FW Certificate of Compliance 72-1032 Amendment No. 5, effective 7/27/2020, ML20163A701.
2 EA-23-0 44: Holtec International, INC. - Notice of Violation; The U.S. Nuclear Regulatory Commission Inspection Report N o. 07201032/2022-201, ML24016A190.
3 NRC Memorandum, Safety Determination of a Potential Structural Failure of the Fuel Basket During Ac cident Conditions for the HI -STORM 100 and HI-STORM Flood/Wind Dry Cask Storage Systems, dated January 31, 2024, ML24018A085.