Exelon Generation Company, LLC; TMI-2 Solutions, LLC; Three Mile Island Nuclear Station, Units 1 and 2, 14472-14478 [2021-05396]

Agencies

• NUCLEAR REGULATORY COMMISSION

[Federal Register Volume 86, Number 49 (Tuesday, March 16, 2021)]
[Notices]
[Pages 14472-14478]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-05396]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. 50-289 and 50-320; NRC-2021-0069]


Exelon Generation Company, LLC; TMI-2 Solutions, LLC; Three Mile 
Island Nuclear Station, Units 1 and 2

AGENCY: Nuclear Regulatory Commission.

ACTION: Exemptions; issuance.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) has issued 
exemptions in response to a request to reduce the required level of 
primary offsite liability insurance from $450 million to $100 million 
and to eliminate the requirement to carry secondary financial 
protection for Three Mile Island Nuclear Station, Unit 1 and to reduce 
the required level of primary offsite liability insurance in the event 
of an extraordinary nuclear occurrence from $200 million to $100 
million for Three Mile Island Nuclear Station, Unit 2.

DATES: The exemptions were issued on March 9, 2021.

ADDRESSES: Please refer to Docket ID NRC-2021-0069 when contacting the 
NRC about the availability of information regarding this document. You 
may obtain publicly available information related to this document 
using any of the following methods:
     Federal Rulemaking website: Go to https://www.regulations.gov and search for Docket ID NRC-2021-0069. Address 
questions about Docket IDs in Regulations.gov to Stacy Schumann; 
telephone: 301-415-0624; email: [email protected]. For technical 
questions, contact the individual listed in the FOR FURTHER INFORMATION 
CONTACT section of this document.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may obtain publicly available documents online in the 
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``Begin Web-based ADAMS 
Search.'' For problems with ADAMS, please contact the NRC's Public 
Document Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or 
by email to [email protected]. The ADAMS accession number for each 
document referenced (if it is available in ADAMS) is provided the first 
time that it is mentioned in this document.
     Attention: The PDR, where you may examine and order copies 
of public documents, is currently closed. You may submit your request 
to the PDR via email at [email protected] or call 1-800-397-4209 or 
301-415-4737, between 8:00 a.m. and 4:00 p.m. (EST), Monday through 
Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Theodore Smith, Office of Nuclear 
Material Safety and Safeguards, U.S. Nuclear Regulatory Commission, 
Washington, DC 20555-0001; telephone: 301-415-6721, email: 
[email protected].

SUPPLEMENTARY INFORMATION: The text of the exemptions is attached.

    Dated: March 11, 2021.

    For the Nuclear Regulatory Commission.
Bruce A. Watson,
Chief, Reactor Decommissioning Branch, Division of Decommissioning, 
Uranium Recovery and Waste Programs, Office of Nuclear Material Safety 
and Safeguards.

Attachment--Exemption

NUCLEAR REGULATORY COMMISSIOIN

Docket Nos. 50-289 and 50-320

Exelon Generation Company, LLC

TMI-2 Solutions, LLC

Three Mile Island Nuclear Station, Units 1 and 2 Exemptions

I. Background

    By letter dated June 20, 2017 (Agencywide Documents Access and 
Management System [ADAMS] Accession No. Main Library [ML] ML17171A151), 
Exelon Generation Company, LLC (Exelon) certified to the U.S. Nuclear 
Regulatory Commission (NRC, the Commission) that it planned to 
permanently cease power operations at Three Mile Island Nuclear 
Station, Unit 1 (TMI-1) on or about September 30, 2019. On September 
20, 2019, Exelon permanently ceased power operations at TMI-1. By 
letter dated September 26, 2019 (ADAMS Accession No. ML19269E480), 
Exelon certified to the NRC that the fuel was permanently removed from 
the TMI-1 reactor vessel and placed in the spent fuel pool (SFP) as of 
September 26, 2019. Accordingly,

[[Page 14473]]

pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 
Section 50.82(a)(2), the TMI-1 renewed facility operating license no 
longer authorizes operation of the reactor or emplacement or retention 
of fuel in the reactor vessel. The facility is still authorized to 
possess and store irradiated (i.e., spent) nuclear fuel. Spent fuel is 
currently stored onsite at the TMI-1 facility in the SFP.
    Three Mile Island Nuclear Station, Unit 2 (TMI-2) was a 2,770 
megawatts thermal pressurized light-water reactor supplied by Babcock & 
Wilcox that was issued an operating license on February 8, 1978 and 
began commercial operations on December 30, 1978. On March 28, 1979, 
TMI-2 experienced an accident that resulted in severe damage to the 
reactor core. Subsequently, approximately 99 percent of the fuel and 
damaged core material was removed from the TMI-2 reactor vessel and 
associated systems and shipped to the U.S. Department of Energy Idaho 
National Laboratory. After the completion of accident recovery 
operations, TMI-2 was placed in a Post-Defueling Monitored Storage 
(PDMS) state on September 14, 1993, with a possession only license that 
authorizes the possession of byproduct and special nuclear materials 
but not the operation of the reactor.
    Following the TMI-2 accident, in 1982, the NRC granted an exemption 
from the requirements of 10 CFR 140.11(a)(4) for TMI-1 and TMI-2 
(ML19141A211). The exemption allowed the licensees to provide two 
endorsements to meet the financial protection requirements of 
subsection 170 of the Atomic Energy Act of 1954, as amended. The first 
endorsement, Endorsement No. 43, restored the limits of liability to 
the amounts listed in other endorsements upon an ``extraordinary 
nuclear occurrence'' (ENO) being declared by the NRC arising out of the 
ownership, operation, maintenance, or use of TMI-1 and/or TMI-2. The 
second endorsement, Endorsement No. 44, increased the TMI-1 liability 
limit to the NRC limit in effect at the time for any bodily injury or 
property damages caused by a nuclear energy hazard, but increased the 
TMI-2 liability limit only in the event the NRC declared an ENO on or 
after May 1, 1979. Subsequently, in 1994, the NRC granted TMI-2 an 
exemption from participation in secondary financial protection (ADAMS 
Accession No. 9408050260 [Legacy Library]). The exemptions herein do 
not impact the exemptions already in place.

II. Request/Action

    By letter dated January 3, 2020 (ADAMS Accession No. ML20003E096), 
Exelon requested an exemption from 10 CFR 140.11(a)(4) to reduce the 
required level of primary offsite liability insurance from $450 million 
to $100 million and to eliminate the requirement to carry secondary 
financial protection for TMI-1 and TMI-2 Solutions, LLC (TMI-2 
Solutions) \1\ requested an exemption from 10 CFR 140.11(a)(4) to 
reduce the required level of primary offsite liability insurance in the 
event of an ENO \2\ from $200 million to $100 million for TMI-2.
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    \1\ The TMI-2 license was transferred to TMI-2 Solutions on 
December 18, 2020 (ADAMS Accession No. ML20352A381).
    \2\ Pursuant to 10 CFR 140.83, if the Commission determines that 
both of the criteria set forth in 10 CFR 140.84 and 140.85 have been 
met, it will make the determination that there has been an ENO.
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    The regulation at 10 CFR 140.11(a)(4) requires each licensee to 
have and maintain primary financial protection in an amount of $450 
million. In addition, the licensee is required to participate in an 
industry retrospective rating plan (secondary financial protection) 
that commits each licensee to pay into an insurance pool to be used for 
damages that may exceed primary insurance coverage. Participation in 
the industry retrospective rating plan will subject the licensee to 
deferred premium charges up to a maximum total deferred premium of 
$131,056,000 with respect to any nuclear incident at any operating 
nuclear power plant and up to a maximum annual deferred premium of 
$20,496,000 per incident.
    Many of the accident scenarios postulated in the updated safety 
analysis reports for operating power reactors involve failures or 
malfunctions of systems, which could affect the fuel in the reactor 
core and, in the most severe postulated accidents, would involve the 
release of large quantities of fission products. With the permanent 
cessation of power operations at TMI-1 and the permanent removal of the 
fuel from the reactor vessel, and the PDMS state of TMI-2 with no fuel 
assemblies in the TMI-2 reactor or the TMI-2 SFP, many accidents are no 
longer possible. Similarly, the associated risk of offsite liability 
damages that would require insurance or indemnification is 
commensurately lower for such plants. Therefore, Exelon requested an 
exemption from 10 CFR 140.11(a)(4) to permit a reduction in primary 
offsite liability insurance and to withdraw from participation in the 
industry retrospective rating plan for TMI-1. Additionally, TMI-2 
Solutions requested an exemption from 10 CFR 140.11(a)(4) to permit a 
reduction in primary offsite liability insurance to $100 million in the 
event of an ENO for TMI-2.

III. Discussion

    Pursuant to 10 CFR 140.8, ``Specific exemptions,'' the Commission 
may, upon application of any interested person or upon its own 
initiative, grant such exemptions from the requirements of the 
regulations in 10 CFR part 140 when the exemptions are authorized by 
law and are otherwise in the public interest. The NRC staff has 
reviewed the licensees' request for exemptions from 10 CFR 140.11(a)(4) 
and has concluded that the requested exemptions are authorized by law 
and are otherwise in the public interest.
    The Price Anderson Act of 1957 (PAA) requires that nuclear power 
reactor licensees have insurance to compensate the public for damages 
arising from a nuclear incident. Specifically, the PAA requires 
licensees of facilities with a ``rated capacity of 100,000 electrical 
kilowatts or more'' to maintain the maximum amount of primary offsite 
liability insurance commercially available (currently $450 million) and 
a specified amount of secondary insurance coverage (currently up to 
$131,056,000 per reactor). In the event of an accident causing offsite 
damages in excess of $450 million, each licensee would be assessed a 
prorated share of the excess damages, up to $131,056,000 per reactor, 
for a total of approximately $13 billion per nuclear incident. The 
NRC's regulations at 10 CFR 140.11(a)(4) implement these PAA insurance 
requirements and set forth the amount of primary and secondary 
insurance each power reactor licensee must have.
    As noted above, the PAA requirements with respect to primary and 
secondary insurance and the implementing regulations at 10 CFR 
140.11(a)(4) apply to licensees of facilities with a ``rated capacity 
of 100,000 electrical kilowatts or more.'' In accordance with 10 CFR 
50.82(a)(2), the license for a power reactor no longer authorizes 
operation of the reactor or emplacement or retention of fuel into the 
reactor vessel upon the docketing of the certifications for permanent 
cessation of operations and permanent removal of fuel from the reactor 
vessel, or when a final legally effective order to permanently cease 
operations has come into effect. Therefore, the reactor cannot be used 
to generate power.
    Accordingly, a reactor that is undergoing decommissioning has no 
``rated capacity.'' Thus, the NRC may take the reactor licensee out of 
the category of reactor licensees that are required to maintain the 
maximum available insurance and to participate in

[[Page 14474]]

the secondary retrospective insurance pool.
    The financial protection limits of 10 CFR 140.11(a)(4) were 
established to require a licensee to maintain sufficient insurance, as 
specified under the PAA, to satisfy liability claims by members of the 
public for personal injury, property damage, and the legal cost 
associated with lawsuits as the result of a nuclear accident at an 
operating reactor with a rated capacity of 100,000 kilowatts electric 
or greater. Thus, the insurance levels established by this regulation, 
as required by the PAA, were associated with the risks and potential 
consequences of an accident at an operating reactor with a rated 
capacity of 100,000 kilowatts electric or greater.
    The legal and associated technical basis for granting exemptions 
from 10 CFR part 140 is set forth in SECY-93-127, ``Financial 
Protection Required of Licensees of Large Nuclear Power Plants During 
Decommissioning,'' dated May 10, 1993 (ADAMS Accession No. 
ML12257A628). The legal analysis underlying SECY-93-127 concluded that, 
upon a technical finding that lesser potential hazards exist after 
permanent cessation of power operations (and the reactor having no 
``rated capacity''), the Commission has the discretion under the PAA to 
reduce the amount of insurance required of a licensee undergoing 
decommissioning.
    As a technical matter, the fact that a reactor has permanently 
ceased power operations is not itself determinative as to whether a 
licensee may cease providing the offsite liability coverage required by 
the PAA and 10 CFR 140.11(a)(4). In light of the presence of freshly 
discharged irradiated fuel in the SFP at a recently shut down reactor, 
the potential for an offsite radiological release from a zirconium fire 
with consequences comparable in some respects to an operating reactor 
accident remains. That risk is very low at the time of reactor shut 
down because of design provisions that prevent a significant reduction 
in coolant inventory in the SFP under normal and accident conditions 
and becomes no longer credible once the continual reduction in decay 
heat provides ample time to restore coolant inventory and permits air-
cooling in a drained SFP. After that time, the probability of a large 
offsite radiological release from a zirconium fire is negligible for 
permanently shut down reactors, but the SFP is still operational and an 
inventory of radioactive materials still exists onsite. Therefore, an 
evaluation of the potential for offsite damage is necessary to 
determine the appropriate level of offsite insurance post shut down, in 
accordance with the Commission's discretionary authority under the PAA 
to establish an appropriate level of required financial protection for 
such permanently shut down facilities.
    The NRC staff has conducted an evaluation and concluded that, aside 
from the handling, storage, and transportation of spent fuel and 
radioactive materials for a permanently shut down and defueled reactor, 
no reasonably conceivable potential accident exists that could cause 
significant offsite damage. During normal power reactor operations, the 
forced flow of water through the reactor coolant system (RCS) removes 
heat generated by the reactor. The RCS transfers this heat away from 
the reactor core by converting reactor feedwater to steam, which then 
flows to the main turbine generator to produce electricity. Most of the 
accident scenarios postulated for operating power reactors involve 
failures or malfunctions of systems that could affect the fuel in the 
reactor core, which in the most severe postulated accidents would 
involve the release of large quantities of fission products. With the 
permanent cessation of reactor operations at the TMI site and the 
permanent removal of the fuel from the reactor core, such accidents are 
no longer possible. The reactor, RCS, and supporting systems no longer 
operate and have no function related to the storage of the irradiated 
fuel. Therefore, postulated accidents involving failure or malfunction 
of the reactor, RCS, or supporting systems are no longer applicable.
    During reactor decommissioning, the principal radiological risks 
are associated with the storage of spent fuel onsite. On a case-by-case 
basis, licensees undergoing decommissioning have been granted 
permission to reduce the required amount of primary offsite liability 
insurance coverage from $450 million to $100 million and to withdraw 
from the secondary insurance pool. One of the technical criteria for 
granting the exemption is that the possibility of a design-basis event 
that could cause significant offsite damage has been eliminated.
    In its exemption request, Exelon described both design-basis and 
beyond-design-basis events involving irradiated fuel stored in the TMI-
1 SFP. Exelon stated, and the NRC staff agrees, that while spent fuel 
remains in the SFP, the only postulated design-basis accident that 
would remain applicable to TMI-1 in the permanently defueled condition 
that could contribute a significant dose is a fuel handling accident 
(FHA) in the Reactor Building, where the SFP is located. For 
completeness, the NRC staff also evaluated the applicability of other 
design-basis accidents documented in the TMI-1 Updated Final Safety 
Analysis Report (UFSAR) (ADAMS Package Accession No. ML18117A343) to 
ensure that these accidents would not have consequences that could 
potentially exceed the 10 CFR 50.67 dose limits and Regulatory Guide 
1.183, ``Alternative Radiological Source Terms for Evaluating Design 
Basis Accidents at Nuclear Power Reactors,'' dose acceptance criteria 
or approach the U.S. Environmental Protection Agency (EPA) early phase 
protective action guides (PAGs).
    In the TMI-1 UFSAR, the licensee has determined that 365 days after 
shut down, the FHA doses would decrease to a level that would not 
warrant protective actions under the EPA early phase PAG framework, 
notwithstanding meeting the dose limit requirements under 10 CFR 50.67 
and dose acceptance criteria under Regulatory Guide 1.183. The NRC 
staff notes that the doses from an FHA are dominated by the isotope 
Iodine-131. TMI-1 permanently ceased power operations on September 20, 
2019. With 488 days of decay, the thyroid dose from an FHA would be 
negligible and the only isotope remaining in significant amounts, among 
those postulated to be released in a design-basis FHA, would be 
Krypton-85. Since Krypton-85 primarily decays by beta emission, the 
calculated skin dose from an FHA analysis would make an insignificant 
contribution to the total effective dose equivalent, which is the 
parameter of interest in the determination of the EPA early phase PAGs 
for sheltering or evacuation. The NRC staff concludes that the dose 
consequence from an FHA for the permanently shut down TMI-1 would not 
approach the EPA early phase PAGs. Therefore, any offsite consequence 
from a design-basis radiological release is highly unlikely and, thus, 
a significant amount of offsite liability insurance coverage is not 
required.
    The only beyond design-basis event that has the potential to lead 
to a significant radiological release at a permanently shut down and 
defueled reactor is a zirconium fire. The zirconium fire scenario is a 
postulated, but highly unlikely, accident scenario that involves the 
loss of water inventory from the SFP resulting in a significant heat up 
of the spent fuel and culminating in substantial zirconium cladding 
oxidation and fuel damage. The probability of a zirconium fire scenario 
is related to the decay heat of the irradiated fuel stored in the SFP. 
Therefore, the risks from a zirconium

[[Page 14475]]

fire scenario continue to decrease as a function of the time that TMI-1 
has been permanently shut down.
    In the analysis provided in Attachment 2, ``Three Mile Island 
Nuclear Station Zirconium Fire Analysis for Drained Spent Fuel Pool 
(Calculation C-1101-202-E410-476, Revision 1),'' to the letter dated 
July 1, 2019 (ADAMS Accession No. ML19182A104), the licensee compared 
the conditions for the hottest fuel assembly stored in the SFP to a 
criterion proposed in SECY-99-168, ``Improving Decommissioning 
Regulations for Nuclear Power Plants,'' dated June 30, 1999 (ADAMS 
Accession No. ML12265A598), applicable to offsite emergency response 
for the unit in the decommissioning process. This criterion considers 
the time for the hottest assembly to heat up from 30 degrees Celsius 
([deg]C) to 900 [deg]C adiabatically. If the heat up time is greater 
than 10 hours, then offsite emergency preplanning involving the plant 
is not necessary. Based on the limiting fuel assembly for decay heat 
and adiabatic heat up analysis presented in Attachment 2, at 488 days 
(approximately 16 months) after permanent cessation of power 
operations, the time for the hottest fuel assembly to reach 900 [deg]C 
is 10 hours after the assemblies have been uncovered. As stated in 
NUREG-1738, ``Technical Study of Spent Fuel Pool Accident Risk at 
Decommissioning Nuclear Power Plants,'' dated February 2001 (ADAMS 
Accession No. ML010430066), 900 [deg]C is an acceptable temperature to 
use for assessing onset of fission product release under transient 
conditions to establish the critical decay time for determining the 
availability of 10 hours for deployment of mitigation equipment and, if 
necessary, for offsite agencies to take appropriate action to protect 
the health and safety of the public if fuel and cladding oxidation 
occurs in air.
    The NRC staff reviewed the calculation to verify that important 
physical properties of materials were within acceptable ranges and the 
results were accurate. The NRC staff determined that physical 
properties were appropriate and completed independent confirmatory 
calculations that produced similar results. Therefore, the NRC staff 
found that after 488 days of decay, at least 10 hours would be 
available before a significant offsite release could begin. The NRC 
staff concluded that the adiabatic heat up calculation provided an 
acceptable method for determining the minimum time available for 
deployment of mitigation equipment and, if necessary, implementing 
measures under a comprehensive general emergency plan.
    In this regard, one technical criterion for relieving 
decommissioning reactor licensees from the insurance obligations 
applicable to an operating reactor is a finding that the heat generated 
by the SFP has decayed to the point where the possibility of a 
zirconium fire is highly unlikely. This was addressed in SECY-93-127, 
where the NRC staff concluded that there was a low likelihood and 
reduced short-term public health consequences of a zirconium fire once 
a decommissioning plant's spent fuel has sufficiently decayed. In its 
Staff Requirements Memorandum, ``Financial Protection Required of 
Licensees of Large Nuclear Power Plants during Decommissioning,'' dated 
July 13, 1993 (ADAMS Accession No. ML003760936), the Commission 
approved a policy that authorized, through the exemption process, 
withdrawal from participation in the secondary insurance layer and a 
reduction in commercial liability insurance coverage to $100 million 
when a licensee is able to demonstrate that the spent fuel could be 
air-cooled if the SFP was drained of water.
    The NRC staff has used this technical criterion to grant similar 
exemptions to other decommissioning reactors (e.g., Maine Yankee Atomic 
Power Station, published in the Federal Register (FR) on January 19, 
1999 (64 FR 2920); Zion Nuclear Power Station, published in the Federal 
Register on December 28, 1999 (64 FR 72700); Kewaunee Power Station, 
published in the Federal Register on March 24, 2015 (80 FR 15638); 
Crystal River Unit 3 Nuclear Generation Plant, published in the Federal 
Register on May 6, 2015 (80 FR 26100); Oyster Creek Nuclear Generating 
Station, published in the Federal Register on December 28, 2018 (83 FR 
67365); and Pilgrim Nuclear Power Station, published in the Federal 
Register on January 13, 2020 (85 FR 1827)).
    Additional discussions of other decommissioning reactor licensees 
that have received exemptions to reduce their primary insurance level 
to $100 million are provided in SECY-96-256, ``Changes to the Financial 
Protection Requirements for Permanently Shutdown Nuclear Power 
Reactors, 10 CFR 50.54(w) and 10 CFR 140.11,'' dated December 17, 1996 
(ADAMS Accession No. ML15062A483). These prior exemptions were based on 
the licensee demonstrating that the SFP could be air-cooled consistent 
with the technical criterion discussed above.
    The NRC staff has evaluated the issue of zirconium fires in SFPs 
and presented an independent evaluation of an SFP subject to a severe 
earthquake in NUREG-2161, ``Consequence Study of a Beyond-Design-Basis 
Earthquake Affecting the Spent Fuel Pool for a U.S. Mark l Boiling 
Water Reactor,'' dated September 2014 (ADAMS Accession No. 
ML14255A365). This evaluation concluded that, for a representative 
boiling-water reactor, fuel in a dispersed high-density configuration 
would be adequately cooled by natural circulation air flow within 
several months after discharge from a reactor if the pool was drained 
of water.
    In its exemption request, Exelon compared TMI-1 fuel storage 
parameters with those used in NRC generic evaluations of fuel cooling 
included in NUREG/CR-6451, ``A Safety and Regulatory Assessment of 
Generic BWR [Boiling-Water Reactor] and PWR [Pressurized-Water Reactor] 
Permanently Shut down Nuclear Power Plants,'' dated August 1997 (ADAMS 
Accession No. ML082260098). The analysis described in NUREG/CR-6451 
determined that natural air circulation would adequately cool fuel that 
has decayed for 17 months after operation in a typical PWR, which is a 
slightly longer decay time than the zirconium fire period of 488 days 
on which the TMI-1 exemption request is based. In order to evaluate if 
the TMI-1 decay period was conservative, Exelon examined the decay heat 
at TMI-1 and determined that the average fuel assembly decay heat for 
the most recently offloaded TMI-1 spent fuel at 488 days after shut 
down will be approximately 3 percent less than the decay heat for the 
average fuel assembly at 519 days for the representative PWR plant in 
NUREG/CR-6451.
    A comparison of the parameters for the fuel assembly power, power 
density, and hydraulic resistance of the 15x15 fuel assemblies at TMI-1 
indicated that these parameters are less than those of the 17x17 fuel 
assemblies modeled in NUREG/CR-6451. Therefore, the NUREG/CR-6451 fuel 
assembly model is conservative for TMI-1. The SFP rack configuration 
was also evaluated and found to be conservative for TMI-1. The 
configuration/hydraulic resistance of the TMI-1 downcomers and plenum 
underneath the SFP storage racks is bounded by that modeled in NUREG/
CR-6451. Additionally, the hydraulic resistance of the SFP rack loaded 
cells is less than that of the SFP rack configuration modeled in NUREG/
CR-6451. The bottom orifices on all TMI-1 SFP racks are equal to or 
larger than those modeled in NUREG/CR-6451, which also makes the 
estimates for TMI-1 more conservative.

[[Page 14476]]

    As a result of the comparison, Exelon concluded that the TMI-1 SFP 
conditions are bounded by the NUGREG/CR-6451 benchmark and that the 
TMI-1 spent fuel would be air-coolable at 488 days after permanent shut 
down. Therefore, at 16 months after permanent shut down, the NRC staff 
has reasonable assurance that fuel stored in the TMI-1 SFP would be 
adequately air-cooled in the unlikely event the SFP completely drained.
    In SECY-00-0145, ``Integrated Rulemaking Plan for Nuclear Power 
Plant Decommissioning,'' dated June 28, 2000, and SECY-01-0100, 
``Policy Issues Related to Safeguards, Insurance, and Emergency 
Preparedness Regulations at Decommissioning Nuclear Power Plants 
Storing Fuel in Spent Fuel Pools,'' dated June 4, 2001 (ADAMS Accession 
Nos. ML003721626 and ML011450420, respectively), the NRC staff 
discussed additional information concerning SFP zirconium fire risks at 
decommissioning reactors and associated implications for offsite 
insurance. Analyzing when the spent fuel stored in the SFP is capable 
of adequate air-cooling is one measure that demonstrates when the 
probability of a zirconium fire would be exceedingly low.
    In addition, the licensee performed adiabatic heat up analyses to 
determine a dose rate curve at the Exclusion Area Boundary (EAB) and 
Control Room. Although the analysis described above demonstrated that a 
significant release of radioactive material from the spent fuel in the 
absence of water cooling is not possible after 488 days following 
permanent cessation of power operations, the potential exists for 
radiation exposure to an offsite individual in the event that shielding 
of the fuel is lost. The site-specific offsite and Control Room 
radiological impacts of a postulated complete loss of SFP water were 
assessed in TMI-1 Technical Evaluation 623073, ``TMI Spent Fuel Pool 
Draindown Shine Dose Rate Evaluation, Revision 0.'' With a decay of 365 
days from shut down, the dose rate at the EAB would be 4.04 x 
10-1mrem/hour not crediting the shielding from 
the Fuel Handling Building (FHB) roof. Crediting the FHB roof 
structure, the dose rate at the EAB would be 4.6 x 
10-10 mrem/hour.
    The licensee's adiabatic heat up analyses demonstrate that 16 
months after the permanent cessation of operations, there would be at 
least 10 hours to take mitigative actions in response to events that 
could lead to a zirconium fire. In addition, the TMI-1 SFP conditions 
were determined to be bounded by the analysis of the NUREG/CR-6451 
benchmark demonstrating that the SFP would be air-coolable at 488 days 
after permanent cessation of operations.
    In its exemption request, Exelon furnished the following 
information: ``Because of the length of time it would take for the 
adiabatic heat up to occur, there is ample time to respond (>=10 hours) 
to any drain down event that might cause such an occurrence by 
restoring [SFP] cooling or makeup or providing [SFP] spray. As a 
result, the likelihood that such a scenario would progress to a 
zirconium fire is not deemed credible.''
    In the NRC staff's evaluation contained in SECY-20-0041, ``Request 
by Exelon Generation Company, LLC for Exemptions from Certain Emergency 
Planning Requirements for the Three Mile Island Nuclear Station,'' 
dated May 5, 2020 (ADAMS Accession No. ML19311C763), the NRC staff 
assessed the Exelon accident analyses associated with the radiological 
risks from a zirconium fire at a permanently shut down and defueled TMI 
site. For the highly unlikely beyond design-basis accident scenario 
where the SFP coolant inventory is lost in such a manner that all 
methods of heat removal from the spent fuel are no longer available, 
the NRC staff found that there will be a minimum of 10 hours from the 
initiation of the accident until the cladding reaches a temperature 
where offsite radiological release might occur. The NRC staff finds 
that 10 hours is sufficient time to support deployment of mitigation 
equipment, consistent with plant conditions, to prevent the zirconium 
cladding from reaching a point of rapid oxidation.
    The NRC staff has determined that the licensee's proposed reduction 
in primary offsite liability coverage to a level of $100 million and 
the licensee's proposed withdrawal from participation in the secondary 
insurance pool for offsite financial protection are consistent with the 
policy established in SECY-93-127 and subsequent insurance 
considerations resulting from zirconium fire risks, as discussed in 
SECY-00-0145 and SECY-01-0100. The NRC has previously determined in 
SECY-00-0145 that the minimum offsite financial protection requirement 
may be reduced to $100 million and that secondary insurance is not 
required once it is determined that the spent fuel in the SFP is no 
longer thermal-hydraulically capable of sustaining a zirconium fire 
based on a plant-specific analysis. In addition, the NRC staff notes 
that similar exemptions from these insurance requirements have been 
granted to other permanently shut down and defueled power reactors upon 
satisfactory demonstration that zirconium fire risk from the irradiated 
fuel stored in the SFP is of negligible concern.
    As provided in SECY-93-127, the NRC staff included in its 
recommendations that using the standards set forth in SECY-93-127, 
primary financial protection could be reduced to $100 million for 
nuclear power plants that have had the requisite spent fuel cooling 
period. However, as specifically mentioned in SECY-93-127 (Note 5), for 
TMI-2 ``primary financial protection covering the site will remain at 
$200 million [the full required regulatory value at the time of the 
issuance of SECY-93-127] because there is at least one other operating 
reactor on [the] site.'' Since TMI-1 is no longer authorized to 
operate, there is no longer at least one other operating reactor on the 
TMI site. Therefore, TMI-2 Solutions requested a corresponding 
exemption from 10 CFR 140.11(a)(4) for TMI-2 to permanently reduce the 
required level of primary offsite liability insurance for ENOs from 
$200 million to $100 million. As discussed above, TMI-2 is maintained 
in a PDMS state with a possession only license that authorizes the 
possession of byproduct and special nuclear materials but not the 
operation of the reactor.
    The NRC staff evaluated the applicability of a waste gas tank 
rupture as documented in the TMI-1 UFSAR, and the applicability of any 
unanticipated releases as documented in the Unanticipated Events 
Analysis in the TMI-2 Post-Defueling Monitored Storage Safety Analysis 
Report (ADAMS Package Accession No. ML17236A295), to ensure that these 
accidents would not have consequences that could potentially exceed the 
10 CFR 50.67 dose limits and Regulatory Guide 1.183 dose acceptance 
criteria or approach the EPA early phase PAGs. Exelon stated that the 
bounding event for TMI-2 is a fire in the Reactor Building with the 
Reactor Building Purge System in operation. The NRC staff reviewed the 
assumptions, inputs, and methods used by Exelon to assess the 
radiological impacts of the requested exemption. The NRC staff 
concludes that Exelon has demonstrated that the dose consequences for 
postulated accidents at the permanently defueled TMI facility would not 
have consequences that could potentially exceed the applicable dose 
limits in 10 CFR 100.11, ``Determination of exclusion area, low 
population zone, and population center distance,'' and 10 CFR 50.67, 
and the dose acceptance criteria in Regulatory Guide 1.183. The 
analysis demonstrates

[[Page 14477]]

that 365 days after permanent cessation of power operations, the 
radiological consequences of the analyzed design-basis accidents will 
not exceed the limits of the EPA early phase PAGs at the EAB. 
Therefore, the NRC staff finds the requested exemption to be acceptable 
from a dose consequence perspective.
    The most significant accident sequence for a permanently defueled 
and shut down reactor involves the complete loss of water from the 
spent fuel pool. As the NRC previously recognized when issuing an 
exemption for TMI-2 from the requirement to participate in secondary 
financial protection, this accident scenario is not credible or 
reasonably conceivable at TMI-2 since the spent fuel pool is drained 
and no spent fuel is stored in the pool. Since TMI-2 is being 
maintained in a PDMS state with the reactor defueled and no fuel in the 
TMI-2 SFP, TMI-2 meets the criterion established in SECY-93-127 for 
relief from the requirements to maintain primary offsite liability 
insurance for ENOs at a level above $100 million. As discussed 
previously, TMI-2 has already received an exemption from participation 
in the secondary retrospective insurance pool. Because the criteria 
presented in SECY-93-127 for removal from the secondary financial 
protection requirement are identical to those for reducing the primary 
offsite liability insurance, there is precedent for allowing the 
reduction of offsite liability insurance for TMI (as a site), once TMI-
1 has met the criteria in SECY-93-127. In addition, the NRC staff notes 
that similar exemptions from these insurance requirements have been 
granted to other permanently shut down and defueled power reactors, 
upon satisfactory demonstration that zirconium fire risk from the 
irradiated fuel stored in the SFP is of negligible concern.

A. The Exemptions Are Authorized by Law

    The PAA and its implementing regulations in 10 CFR 140.11(a)(4) 
require licensees of nuclear reactors that have a rated capacity of 
100,000 kilowatts electric or more to have and maintain $450 million in 
primary financial protection and to participate in a secondary 
retrospective insurance pool. In accordance with 10 CFR 140.8, the 
Commission may grant exemptions from the regulations in 10 CFR part 140 
as the Commission determines are authorized by law. The legal and 
associated technical basis for granting exemptions from 10 CFR part 140 
are set forth in SECY-93-127. The legal analysis underlying SECY-93-127 
concluded that, upon a technical finding that lesser potential hazards 
exist after permanent cessation of operations, the Commission has the 
discretion under the PAA to reduce the amount of insurance required of 
a licensee undergoing decommissioning.
    Based on its review of the exemption requests, the NRC staff 
concludes that the technical criteria for relieving Exelon and TMI-2 
Solutions from their existing primary and/or secondary insurance 
obligations have been met. As explained above, the NRC staff found that 
no reasonably conceivable design-basis accident exists that could cause 
an offsite release greater than the EPA PAGs and, therefore, that any 
offsite consequence from a design-basis radiological release is highly 
unlikely and the need for a significant amount of offsite liability 
insurance coverage is unwarranted. Additionally, the NRC staff 
determined that, after 16 months decay, the fuel stored in the TMI-1 
SFP will be capable of being adequately cooled by air in the highly 
unlikely event of pool drainage. Moreover, in the highly unlikely 
beyond design-basis accident scenario where the SFP coolant inventory 
is lost in such a manner that all methods of heat removal from the 
spent fuel are no longer available, the NRC staff has determined that 
at least 10 hours would be available and is sufficient time to support 
deployment of mitigation equipment, consistent with plant conditions, 
to prevent the zirconium cladding from reaching a point of rapid 
oxidation. Thus, the NRC staff concludes that the fuel stored in the 
TMI-1 SFP will have decayed sufficiently by the requested effective 
date for the exemptions of 16 months after permanent cessation of power 
operations to support a reduction in the required insurance consistent 
with SECY-00-0145. Moreover, since the criteria presented in SECY-93-
127 for removal from the secondary financial protection requirement are 
identical to those for reducing the primary offsite liability 
insurance, there is precedent for allowing the reduction of offsite 
liability insurance for TMI (as a site), once TMI-1 has met the 
criteria in SECY-93-127.
    The NRC staff has determined that granting the licensees' proposed 
exemptions will not result in a violation of the Atomic Energy Act of 
1954, Section 170, or other laws, as amended, which require licensees 
to maintain adequate financial protection. Accordingly, consistent with 
the legal standard presented in SECY-93-127, under which 
decommissioning reactor licensees may be relieved of the requirements 
to carry the maximum amount of insurance available and to participate 
in the secondary retrospective premium pool where there is sufficient 
technical justification, the NRC staff concludes that the requested 
exemptions are authorized by law.

B. The Exemptions Are Otherwise in the Public Interest

    The financial protection limits of 10 CFR 140.11 were established 
to require licensees to maintain sufficient offsite liability insurance 
to ensure adequate funding for offsite liability claims following an 
accident at an operating reactor. However, the regulation does not 
consider the reduced potential for and consequence of nuclear incidents 
at permanently shut down and decommissioning reactors.
    The basis provided in SECY-93-127, SECY-00-0145, and SECY-01-0100 
allows licensees of decommissioning plants to reduce their primary 
offsite liability insurance and to withdraw from participation in the 
retrospective rating pool for deferred premium charges. As discussed in 
these documents, once the zirconium fire concern is determined to be 
negligible, possible accident scenario risks at permanently shut down 
and defueled reactors are greatly reduced when compared to the risks at 
operating reactors and the associated potential for offsite financial 
liabilities from an accident are commensurately less. The licensee 
analyzed and the NRC staff confirmed that the risks of accidents that 
could result in an offsite radiological risk are minimal, thereby 
justifying the proposed reductions in offsite primary liability 
insurance and withdrawal from participation in the secondary 
retrospective rating pool for deferred premium charges.
    Additionally, participation in the secondary retrospective rating 
pool could potentially have adverse consequences on the safe and timely 
completion of decommissioning. If a nuclear incident sufficient to 
trigger the secondary insurance layer occurred at another nuclear power 
plant, the licensee could incur financial liability of up to 
$131,056,000. However, because TMI is permanently shut down, it cannot 
produce revenue from electricity generation sales to cover such a 
liability. Therefore, such liability if subsequently incurred could 
significantly affect the ability of the facility to conduct and 
complete timely radiological decontamination and decommissioning 
activities. In addition, as SECY-93-127 concluded, the shared financial 
risk exposure to the licensee is greatly disproportionate to the

[[Page 14478]]

radiological risk posed by TMI when compared to operating reactors. The 
reduced overall risk to the public at decommissioning power plants does 
not warrant that the licensee be required to carry full operating 
reactor insurance coverage after the requisite spent fuel cooling 
period has elapsed following final reactor shut down. The licensee's 
proposed financial protection limits will maintain a level of liability 
insurance coverage commensurate with the risk to the public. These 
changes are consistent with previous NRC policy as discussed in SECY-
00-0145 and exemptions approved for other decommissioning reactors. 
Thus, the underlying purpose of the regulations will not be adversely 
affected by the reductions in insurance coverage. Accordingly, an 
exemption from participation in the secondary insurance pool (for TMI-
1) and a reduction in the primary insurance to $100 million (for TMI-1 
and TMI-2), a value more in line with the potential consequences of 
accidents, would be in the public interest in that this ensures that 
there will be adequate funds to address any of those consequences and 
helps to ensure the safe and timely decommissioning of the reactor.
    Therefore, the NRC staff has concluded that the requested 
exemptions from 10 CFR 140.11(a)(4) at the requested effective date of 
16 months after the permanent cessation of power operations, are in the 
public interest.

C. Environmental Considerations

    The NRC's approval of an exemption from insurance or indemnity 
requirements belongs to a category of actions that the Commission, by 
rule or regulation, has declared to be a categorical exclusion after 
first finding that the category of actions does not individually or 
cumulatively have a significant effect on the human environment. 
Specifically, the exemption is categorically excluded from the 
requirement to prepare an environmental assessment or environmental 
impact statement in accordance with 10 CFR 51.22(c)(25).
    Under 10 CFR 51.22(c)(25), granting of an exemption from the 
requirements of any regulation of Chapter I to 10 CFR is a categorical 
exclusion provided that: (i) There is no significant hazards 
consideration; (ii) there is no significant change in the types or 
significant increase in the amounts of any effluents that may be 
released offsite; (iii) there is no significant increase in individual 
or cumulative public or occupational radiation exposure; (iv) there is 
no significant construction impact; (v) there is no significant 
increase in the potential for or consequences from radiological 
accidents; and (vi) the requirements from which an exemption is sought 
involve surety, insurance, or indemnity requirements.
    As the Director, Division of Decommissioning, Uranium Recovery, and 
Waste Programs, Office of Nuclear Material Safety and Safeguards, I 
have determined that approval of the exemption request involves no 
significant hazards consideration, as defined in 10 CFR 50.92, because 
reducing a licensee's offsite liability requirements at TMI does not: 
(1) Involve a significant increase in the probability or consequences 
of an accident previously evaluated; (2) create the possibility of a 
new or different kind of accident from any accident previously 
evaluated; or (3) involve a significant reduction in a margin of 
safety. The exempted financial protection regulation is unrelated to 
the operation of TMI or site activities. Accordingly, there is no 
significant change in the types or significant increase in the amounts 
of any effluents that may be released offsite and no significant 
increase in individual or cumulative public or occupational radiation 
exposure. The exempted regulation is not associated with construction 
so there is no significant construction impact. The exempted regulation 
does not concern the source term (i.e., potential amount of radiation 
in an accident) nor any activities conducted at the site. Therefore, 
there is no significant increase in the potential for, or consequences 
of, a radiological accident. In addition, there would be no significant 
impacts to biota, water resources, historic properties, cultural 
resources, or socioeconomic conditions in the region resulting from 
issuance of the requested exemptions. The requirement for offsite 
liability insurance involves surety, insurance, or indemnity matters 
only.
    Therefore, pursuant to 10 CFR 51.22(b) and 51.22(c)(25), no 
environmental impact statement or environmental assessment need be 
prepared in connection with the approval of this exemption request.

IV. Conclusions

    Accordingly, the Commission has determined that, pursuant to 10 CFR 
140.8, the requested exemptions are authorized by law and are otherwise 
in the public interest. Therefore, the Commission hereby grants Exelon 
and TMI-2 Solutions exemptions from the requirements of 10 CFR 
140.11(a)(4) for the TMI site. TMI-1 permanently ceased power 
operations on September 20, 2019. The exemptions from 10 CFR 
140.11(a)(4) permit TMI-1 to reduce the required level of primary 
financial protection from $450 million to $100 million and to withdraw 
from participation in the secondary layer of financial protection 16 
months after the permanent cessation of power operations. Further, the 
exemptions permit TMI-2 relief from the requirements to maintain 
primary offsite liability insurance for ENOs at a level above $100 
million.
    The exemptions are effective as of 16 months after permanent 
cessation of power operations.

Dated, this 9th day of March, 2021.

    For the Nuclear Regulatory Commission.

Patricia K. Holahan,

Director, Division of Decommissioning, Uranium Recovery, and Waste 
Programs, Office of Nuclear Material Safety and Safeguards.

[FR Doc. 2021-05396 Filed 3-15-21; 8:45 am]
BILLING CODE 7590-01-P