ML24107A923
| ML24107A923 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 05/08/2024 |
| From: | Yoira Diaz-Sanabria Storage and Transportation Licensing Branch |
| To: | Constellation Energy Generation |
| Shared Package | |
| ML24107A918 | List: |
| References | |
| Download: ML24107A923 (1) | |
Text
Attachment - Exemption
NUCLEAR REGULATORY COMMISSION
Docket Nos. 72 -65, 50-352, and 50- 353
Constellation Energy Generation, LLC
Limerick Generating Station Units 1 and 2
Independent Spent Fuel Storage Installation;
I. Background
Constellation Energy Generation, LLC (Constellation) is the holder of Renewed Facility
Operating License Nos. NPF-39 and NPF-85, which authorize operation of the Limerick
Generating Station ( LGS) Units 1 and 2 in Limerick, Pennsylvania, pursuant to Part 50 of Title
10 of the Code of Federal Regulations (10 CFR), Domestic Licensing of Production and
Utilization Facilities. The licenses provide, among other things, that the facility is subject to all
rules, regulations, and orders of the U.S. Nuclear Regulatory Commission ( NRC) now or
hereafter in effect.
Consistent with 10 CFR part 72, subpart K, General License for Storage of Spent Fuel
at Power Reactor Sites, a general license is issued for the storage of spent fuel in an
Independent Spent Fuel Storage Installation (ISFSI) at power reactor sites to persons
authorized to possess or operate nuclear power reactors under 10 CFR p art 50. Constellation is
authorized to operate nuclear power reactors under 10 CFR p art 50 and holds a 10 CFR part 72
general license for storage of spent fuel at the LGS ISFSI. Under the terms of the general
license, Constellation stores spent fuel at its LGS ISFSI using the HI -STORM Flood/Wind (FW)
Multi-Purpose Canister (MPC) Storage System in accordance with Certifica te of Compliance
(CoC) No. 1032, Amendment No. 1, Revision No. 1.
II. Request/Action
By a letter dated April 5, 2024 (Agencywide Documents Access and Management
System [ADAMS] Accession No. ML24096A137), Constellation requested an exemption from
the requirements of 10 CFR §§ 72.212(a)(2), 72.212(b)(3), 72.212(b)(5)(i), 72.212(b)(11), and
72.214 that require the LGS to comply with the terms, conditions, and specifications o f the CoC
No. 1032, Amendment No. 1, Revision No. 1 (ML15152A358). If approved, Constellations
exemption request would accordingly allow the LGS to maintain three loaded and to load five
MPCs with continuous basket shims (CBS) (i.e., MPC CBS) in the HI-STORM FW MPC
Storage System, and thus, to maintain and load the systems in a storage condition where the
terms, conditions, and specifications in the CoC No. 1032, Amendment No. 1, Revision No. 1,
are not met.
Constellation currently uses the HI-STORM FW MPC Storage System under CoC No.
1032, Amendment No. 1, Revision No. 1, for dry storage of spent nuclear fuel in MPC-89 at the
LGS ISFSI. Holtec International (Holtec), the designer and manufacturer of the HI -STORM FW
MPC Storage System, developed a variant of the design with CBS for the MPC-89 known as
MPC CBS. Holtec performed a non-mechanistic tip-over analysis with favorable results and
implemented the CBS variant design under the provisions of 10 CFR 72.48, Changes, tests,
and experiments, which allows licensees to make changes to cask designs without a CoC
amendment under certain conditions (listed in 10 CFR 72.48(c)). After evaluating the specific
changes to the cask designs, the NRC determined that Holtec erred when it implemented the
CBS variant design under 10 CFR 72.48, as this is not the type of change allowed without a
CoC amendment. For this reason, the NRC issued three Severity Level IV violations to Holtec
(ML24016A190).
Prior to the issuance of the violations, Constellation had loaded three MPC CBS in
the HI-STORM FW MPC Storage System, which are safely in storage at the LGS ISFSI.
2 Constellations near-term loading campaign for the LGS ISFSI include plans to load five MPC-
89-CBS in the HI -STORM FW MPC Storage System beginning in August 2024. While Holtec
was required to submit a CoC amendment to the NRC to seek approval of the CBS variant
design, such a process will not be completed in time to inform decisions for this near-term
loading campaign. Therefore, Constellation submitted this exemption request in order to allow
for the continued storage of the three already loaded MPC-89-CBS, and future loading of five
MPC CBS beginning in August 2024 at the LGS ISFSI. This exemption is limited to the use
of MPC CBS in the HI -STORM FW MPC Storage System only for the three already loaded
canisters and specific near-term planned loading of five new canisters using the MPC-89-CBS
variant basket design.
III. Discussion
Pursuant to 10 CFR 72.7, Specific exemptions, the Commission may, upon application
by any interested person or upon its own initiative, grant such exemptions from the
requirements of the regulations of 10 CFR part 72 as it determines are authorized by law and
will not endanger life or property or the common defense and security and are otherwise in the
public interest.
A. The Exemption is Authorized by Law
This exemption would allow Constellation to maintain three loaded and to load five MPC-
89-CBS in the HI-STORM FW MPC Storage System at its LGS ISFSI in a storage condition
where the terms, conditions, and specifications in the CoC No. 1032, Amendment No. 1,
Revision No. 1, are not met. Constellation is requesting an exemption from the provisions in 10
CFR part 72 that require the licensee to comply with the terms, conditions, and specifications of
the CoC for the approved cask model it uses. Section 72.7 allows the NRC to grant exemptions
from the
3 requirements of 10 CFR part 72. This authority to grant exemptions is consistent with the Atomic
Energy Act of 1954, as amended, and is not otherwise inconsistent with the NRCs regulations
or other applicable laws. Additionally, no other law prohibits the activities that would be
authorized by the exemption. Therefore, the NRC concludes that there is no statutory prohibition
on the issuance of the requested exemption, and the NRC is authorized to grant the exemption
by law.
B. The Exemption Will Not Endanger Life or Property or the Common Defense and
Security
This exemption would allow Constellation to maintain three loaded and to load five MPC-
89-CBS in the HI-STORM FW MPC Storage System at the LGS ISFSI in a storage condition
where the terms, conditions, and specifications in the CoC No. 1032, Amendment No. 1,
Revision No. 1, are not met. In support of its exemption request, Constellation asserts that
issuance of the exemption would not endanger life or property because the administrative
controls the applicant has in place prevent a tip-over or handling event, and that the
containment boundary would be maintained in such an event. Constellation relies, in part, on
the approach in the NRCs Safety Determination Memorandum (ML24018A085). The NRC
issued this Safety Determination Memorandum to address whether, with respect to the
enforcement action against Holtec regarding this violation, there was any need to take an
immediate action for the cask systems that were already loaded with non-compliant basket
designs. The Safety Determination Memorandum documents a risk-informed approach
concluding that, during the design basis event of a non-mechanistic tip-over, the fuel in the
basket in the MPC-89-CBS remains in a subcritical condition.
4 Constellation also provided site-specific technical information, including information
explaining why the use of the approach in the NRCs Safety Determination Memorandum is
appropriate for determining the safe use of the CBS variant baskets at the LGS ISFSI.
Specifically, Constellation described that the analysis of the tip -over design basis event that is
relied upon in the NRCs Safety Determination Memorandum, which demonstrates that the MPC
confinement barrier is maintained, is documented in the updated final safety analysis report
(UFSAR) for the HI-STORM FW MPC Storage System CoC No. 1032, Amendment 1, Revision
No. 1, that is used at the LGS site. Constellation also described its administrative controls for
handling of the HI-STORM FW MPC Storage System at the LGS ISFSI to prevent a tip-over or
handling event. Those controls include using single-failure-proof handling systems as defined in
Section 5.1.6 of NUREG-0612, Control of Heavy Loads at Nuclear Power Plants. The LGSs
UFSAR Section 9.1.5.4 indicates that the single failure proof design of the reactor enclosure
crane conforms to NUREG-0554, Single -Failure-Proof Cranes for Nuclear Power Plants.
Constellation referenced their Rigging and Lifting Program, Control of Heavy Loads Program
and Limerick Generating Station Rigging and Handling Heavy Loads to further demonstrate
that the LGS has applicable operational procedures in place to safely load, process, transfer
and move the MPCs in accordance with the Technical Specifications in Appendix A of the CoC
Additionally, Constellation provided specific information from the LGSs 72.212
Evaluation Report, Revision 3, indicating that during the design basis event of a
non-mechanistic tip-over, the LGSs ISFSI would meet the requirements in 10 CFR 72.104,
Criteria for radioactive materials in effluents and direct radiation from an ISFSI or MRS, and
72.106, Controlled area of an ISFSI or MRS. Specifically, Constellation described that, in the
highly unlikely event of a tip-over, any potential fuel damage from a non-mechanistic tip-over
event would be localized, the confinement barrier would be maintained, and the shielding
5 material would remain intact. Coupled with the distance of the LGS ISFSI to the site area
boundary, Constellation concluded that compliance with 72.104 and 72.106 is not impacted by
approving this exemption request.
The NRC staff reviewed the information provided by Constellation and concludes that
issuance of the exemption would not endanger life or property because the administrative
controls Constellation has in place at the LGS ISFSI sufficiently minimize the possibility of a tip-
over or handling event, and that the containment boundary would be maintained in such an
event. The staff confirmed that these administrative controls are documented in the technical
specifications and UFSAR for the HI -STORM FW MPC Storage System CoC No. 1032,
Amendment 1, Revision No. 1, that is used at the LGS site. In addition, the staff confirmed that
the information provided by Constellation regarding the LGSs 72.212 Evaluation Report,
Revision 3, demonstrates that the consequences of normal and accident conditions would be
within the regulatory limits of the 10 CFR 72.104 and 10 CFR 72.106. The staff also determined
that the requested exemption is not related to any aspect of the physical security or defense of
the LGS ISFSI; therefore, granting the exemption would not result in any potential impacts to
common defense and security.
For these reasons, the NRC staff has determined that under the requested exemption,
the storage system will continue to meet the safety requirements of 10 CFR part 72 and the
offsite dose limits of 10 CFR part 20 and, therefore, will not endanger life or property or the
common defense and security.
C. The Exemption is Otherwise in the Public Interest
The proposed exemption would allow the three already loaded MPC CBS in the HI-
STORM FW MPC Storage System to remain in storage at the LGS ISFSI and allow
Constellation to load five MPC-89-CBS in the HI-STORM FW MPC Storage System beginning
in August 2024 at the LGS ISFSI, even though the CBS variant basket design is not part of the
6 approved CoC No. 1032, Amendment No. 1, Revision No. 1. According to Constellation, the
exemption is in the public interest because unloading fuel from already loaded canisters and not
being able to load fuel into dry storage in future loading campaigns would impact Constellations
ability to offload fuel from the LGS reactor units, consequently impacting continued safe reactor
operation. The reflooding of the MPCs, removal of fuel assemblies, and replacement into a
different MPC would result in additional doses and handling operations with no added safety
benefit. In addition, future loading campaigns would need to be delayed until older design
canisters can be fabricated and delivered to the site.
Constellation stated that to unload already loaded MPC-89-CBS or delay the future
loading campaigns would impact the ability to effectively manage the margin to full core
discharge capacity in the LGS Units 1 and 2 spent fuel pools. The low spent fuel pool capacity
would make it difficult to refuel and present potential risks to fuel handling operations during pre-
and post-outage. In addition, a crowded spent fuel pool w ould challenge the decay heat removal
demand of the pool and increase the likelihood of a loss of fuel pool cooling event and a fuel
handling accident. Furthermore, the LGS planned the cask loading campaigns years in advance
based on availability of the specialized workforce and equipment that is shared throughout the
Constellation fleet. These specialty resources support competing priorities including refueling
outages, loading campaigns, fuel pool cleanouts, fuel inspections, fuel handing equipment
upgrade and maintenance, fuel sipping, new fuel receipt, and crane maintenance and upgrades.
Any delays would have a cascading impact on other scheduled specialized activities.
For the reasons described by Constellation in the exemption request, the NRC agrees
that it is in the public interest to grant the exemption. If the exemption is not granted, in order to
comply with the CoC, Constellation would have to unload MPC CBS from the HI-STORM
FW MPC Storage System at the LGS ISFSI and reload into the older design MPC-89 to restore
compliance with terms, conditions, and specifications of the CoC. This would subject onsite
7 personnel to additional radiation exposure, increase the risk of a possible fuel handling accident,
and increase the risk of a possible heavy load handling accident. Furthermore, the removed
spent fuel would need to be placed in the spent fuel pool until it can be loaded into another
storage cask or remain in the spent fuel pool if it is not permitted to be loaded into casks for
future loading campaigns. As described by Constellation, this scenario would affect
Constellations ability to effectively manage the spent pool capacity and reactor fuel offloading at
the LGS. In addition, the rescheduling of the specialized resources for the future loading
campaigns would impact the operations of the LGS and other Constellation sites.
Therefore, the staff concludes that approving the exemption is in the public interest.
Environmental Consideration
The NRC staff also considered whether there would be any significant environmental
impacts associated with the exemption. For this proposed action, the NRC staff performed an
environmental assessment pursuant to 10 CFR 51.30. The environmental assessment
concluded that the proposed action would not significantly impact the quality of the human
environment. The NRC staff concluded that the proposed action would not result in any changes
in the types or amounts of any radiological or non-radiological effluents that may be released
offsite, and there would be no significant increase in occupational or public radiation exposure
because of the proposed action. The environmental assessment and the f inding of no significant
impact was published on May 8, 2024 (89 FR 38921).
IV.Conclusion
Based on these considerations, the NRC has determined that, pursuant to 10 CFR 72.7,
the exemption is authorized by law, will not endanger life or property or the common defense
and security, and is otherwise in the public interest. Therefore, the NRC grants Constellation an
exemption from the requirements of §§ 72.212(a)(2), 72.212(b)(3), 72.212(b)(5)(i),
72.212(b)(11), and 72.214 with respect to the ongoing storage of three MPC CBS in the HI-
8 STORM FW MPC Storage System and a future loading in the HI -STORM FW MPC Storage
System of five new MPC CBS beginning in August 2024.
This exemption is effective upon issuance.
Dated: May 8, 2024.
For the Nuclear Regulatory Commission.
/RA/
Yoira Diaz-Sanabria, Chief, Storage and Transportation Licensing Branch, Division of Fuel Management, Office of Nuclear Material Safety, and Safeguards.
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ML24107A923 OFFICE NMSS/DFM NMSS/DFM NMSS/REFS NMSS/DFM NAME CJacobs JGoodridge RSun TBoyce
DATE 4/16/2024 4/16/2024 4/17/2024 4/16/2024 OFFICE NMSS/DFM OGC/NLO NMSS/DFM
NAME HRodriguez ACoggins YDiaz-Sanabria DATE 4/17/2024 4/29/2024 5/08/2024