[Federal Register Volume 88, Number 169 (Friday, September 1, 2023)]
[Notices]
[Pages 60507-60510]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-18966]
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NUCLEAR REGULATORY COMMISSION
[NRC-2023-0113]
Draft NUREG: Environmental Evaluation of Accident Tolerant Fuels
With Increased Enrichment and Higher Burnup Levels
AGENCY: Nuclear Regulatory Commission.
ACTION: Draft report; request for comment.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing for
public comment draft NUREG-2266, ``Environmental Evaluation of Accident
Tolerant Fuels with Increased Enrichment and Higher Burnup Levels.''
This study evaluates the reasonably foreseeable impacts of near-term
accident tolerant fuel (ATF) technologies with increased enrichment and
higher burnup levels to 8 wt% uranium-235 (U-235) and up to 80 GWd/MTU,
respectively, on the uranium fuel cycle, transportation of fuel and
waste, and decommissioning for light-water reactors (LWRs) (i.e., a
bounding analysis).
DATES: Submit comments by October 31, 2023. Comments received after
this date will be considered if it is practical to do so, but the
Commission is able to ensure consideration only for comments received
before this date.
ADDRESSES: You may submit comments by any of the following methods;
however, the NRC encourages electronic comment submission through the
Federal rulemaking website:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2023-0113. 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.
Mail Comments to: Office of Administration, Mail Stop:
TWFN-7-A60M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001, ATTN: Program Management, Announcements and Editing Staff.
For additional direction on obtaining information and submitting
comments,
[[Page 60508]]
see ``Obtaining Information and Submitting Comments'' in the
SUPPLEMENTARY INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Donald Palmrose, Office of Nuclear
Material Safety and Safeguards, U.S. Nuclear Regulatory Commission,
Washington, DC 20555-0001; telephone: 301-415-3803, email:
[email protected].
SUPPLEMENTARY INFORMATION:
I. Obtaining Information and Submitting Comments
A. Obtaining Information
Please refer to Docket ID NRC-2023-0113 when contacting the NRC
about the availability of information for this action. You may obtain
publicly available information related to this action by any of the
following methods:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2023-0113.
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, at 301-415-4737,
or by email to [email protected]. The draft NUREG, ``Environmental
Evaluation of Accident Tolerant Fuels with Increased Enrichment and
Higher Burnup,'' is available in ADAMS under Accession No. ML23240A756.
NRC's PDR: The PDR, where you may examine and order copies
of publicly available documents, is open by appointment. To make an
appointment to visit the PDR, please send an email to
[email protected] or call 1-800-397-4209 or 301-415-4737, between 8
a.m. and 4 p.m. eastern time (ET), Monday through Friday, except
Federal holidays.
B. Submitting Comments
The NRC encourages electronic comment submission through the
Federal rulemaking website (https://www.regulations.gov). Please
include Docket ID NRC-2023-0113 in your comment submission.
The NRC cautions you not to include identifying or contact
information that you do not want to be publicly disclosed in your
comment submission. The NRC will post all comment submissions at
https://www.regulations.gov as well as enter the comment submissions
into ADAMS. The NRC does not routinely edit comment submissions to
remove identifying or contact information.
If you are requesting or aggregating comments from other persons
for submission to the NRC, then you should inform those persons not to
include identifying or contact information that they do not want to be
publicly disclosed in their comment submission. Your request should
state that the NRC does not routinely edit comment submissions to
remove such information before making the comment submissions available
to the public or entering the comment into ADAMS.
II. Discussion
To support efficient and effective licensing reviews of new
accident tolerant fuels (ATFs) and to reduce the need for a complex
site-specific environmental review for each ATF license amendment
request, this study evaluated the likely impacts of near-term ATF
technologies with increased enrichment and higher burnup levels on the
uranium fuel cycle, transportation of fuel and waste, and
decommissioning for light-water reactors (LWRs) (i.e., a bounding
analysis). Near-term ATF technologies are coated cladding, doped
pellets, and (iron-chrome-aluminum) FeCrAl cladding. Other long-term
ATF technologies are not a part of this study. The NRC staff evaluated
the impact of increased enrichment and higher burnup levels by
assessing and applying NRC-sponsored ATF technology reports, prior
environmental reviews, transportation studies, and new or updated data
sources to determine the bounding (generic) environmental impacts of
deploying ATF technologies with increased enrichment and higher burnup
levels in LWRs.
The NRC initially considered the environmental impacts of the
uranium fuel cycle in WASH-1248 (ADAMS Accession No. ML14092A628).
There have been significant changes to the front-end processes and NRC-
licensed facilities since the publication of WASH-1248. The most
notable examples of these changes are extracting uranium from the
ground using in situ recovery instead of traditional mining, performing
all enrichment with gaseous centrifuges instead of gaseous diffusion,
and electricity generation moving significantly away from the use of
coal. The result of these various changes is to significantly reduce
the environmental effects from the front-end of the uranium fuel cycle.
Thus, the environmental effects of the front-end of the uranium fuel
cycle from the deployment and use of ATF with increased enrichment is
bounded by the environmental effects provided in Table S-3 under title
10 of the Code of Federal Regulations (10 CFR) section 51.51.
Regarding the back-end of the uranium fuel cycle, the current
practice of long-term storage and management of spent nuclear fuel
(SNF) would still apply to the deployment and use of ATF with increased
enrichment and higher burnup levels. Consistent with NRC regulations
and thermal loading requirements for licensed spent fuel storage cask
systems, specific cooling times in a spent fuel pool would be necessary
prior to transferring the spent fuel to an Independent Spent Fuel
Storage Installation (ISFSI).
A benefit from deployment and use of ATF with increased enrichment
and higher burnup levels would be the longer times between refueling
operations, which would lessen the average annual rate at which
licensees place spent ATF assemblies into the spent fuel pools and
ultimately transfer spent ATF assemblies to an ISFSI relative to the
rate for traditional spent fuel. This could, in turn, lessen the
overall amount of SNF stored at a site and lengthen the time before
licensees need to expand an ISFSI relative to facilities using fuel
with lower enrichments and lower burnup levels. This lessens the
environmental impacts compared to what would occur with current fuel,
which would be consistent with prior NRC environmental evaluations.
Spent ATF storage would be consistent with earlier published analyses,
would not require any significant departure from certified spent fuel
shipping and storage containers, and would continue under an approved
aging management program.
In conducting the generic analysis in the Continued Storage Generic
Environment Impact Statement (GEIS) of NUREG-2157, Volume 1 (ADAMS
Accession No. ML14196A105) and NUREG-2157, Volume 2 (ADAMS Accession
No. ML14196A107), the NRC staff applied conditions and parameters that
are sufficiently conservative to bound the impacts such that any
variances that may occur from site to site are unlikely to result in
environmental impact determinations that are greater than those
presented in the Continued Storage GEIS. Therefore, with respect to ATF
storage, including spent ATF with increased enrichment and higher
burnup levels, the storage period beyond the licensed life for
operation of a reactor for spent ATF would conform with the analysis of
the Continued Storage GEIS, and accordingly, the Continued Storage
[[Page 60509]]
GEIS would bound the impacts from deployment and use of ATF.
The analysis of the transportation of ATF and ATF waste with
increased enrichment and higher burnup levels is based on shipment of
low-level radioactive waste, unirradiated, and spent ATF, including
with increased enrichments and higher burnup levels, by legal weight
trucks in certified transport packages. The transportation impacts are
divided into two parts. The first part considers normal conditions, or
incident-free, transportation, and the second part considers
transportation accidents.
Shipments that take place without the occurrence of accidents are
routine, incident-free shipments and the radiation doses to various
receptors (exposed persons) are called incident-free doses. The vast
majority of radioactive shipments are expected to reach their
destination without experiencing a transportation accident or incident
or releasing any cargo (to date, there have been no shipments of spent
fuel resulting in a release of radioactive material to the
environment). As previously noted, deployment and use of ATF with
increased enrichment and higher burnup levels could result in
lengthening of the time between refueling operations, leading to an
overall reduction of the number of spent fuel assemblies needing to be
shipped offsite on an annual basis. Such reduction would have the
effect to lessen the environmental impacts compared to what would occur
with current fuel and refueling operations due to transportation of
spent fuel. The incident-free impacts from these normal, routine
shipments arise from the low levels of radiation that are emitted
externally from the shipping container.
Incident-free legal weight truck transportation of spent ATF,
including spent ATF with increased enrichment and higher burnup levels,
has been evaluated by considering shipments from six representative LWR
sites to a postulated permanent geological repository for SNF in the
western United States. As a surrogate for such a postulated permanent
geologic repository, the NRC has used the proposed Yucca Mountain,
Nevada site for the transportation analysis. The six LWR sites from
which the shipments originate include:
Brunswick Steam Electric Plant;
Columbia Generating Station;
Dresden Nuclear Power Station;
Enrico Fermi Nuclear Generating Station Unit 2;
Millstone Power Station; and
Turkey Point Nuclear Plant.
For each LWR site, the NRC staff considered and evaluated both
boiling water reactor (BWR) and pressurized water reactor (PWR) spent
ATF shipments, including with increased enrichment and higher burnup
levels, for the purpose of impact comparison owing to the different
release fractions for BWR and PWR fuel designs.
Environmental impacts from these shipments would occur to persons
residing along the transportation corridors between the reactor sites
and the repository, to persons in vehicles passing the spent fuel
shipments in the same and opposite directions, to persons at vehicle
stops (such as rest areas, refueling stations, inspection stations,
etc.), and to transportation crew members. For the purposes of this
analysis, the transportation crew for truck spent fuel shipments
consisted of two drivers. The regulatory maximum crew dose rate of 2
millirem(s) per hour (mrem/hr), and regulatory maximum transport
package surface dose rate of 10 mrem/hr at 2 meters is conservatively
used in the analysis. The characteristics of specific shipping routes
(e.g., population densities, shipping distances) influence the normal
radiological exposures.
The accident risks are the product of the likelihood of an accident
involving a spent fuel shipment and the consequences of a release of
radioactive material resulting from the accident. The likelihood of an
accident is directly proportional to the number of fuel shipments.
Accident risks also include a consequence term. Consequences are
represented by the population dose from a release of radioactive
material given that an accident occurs that leads to a breach in the
shipping cask's containment systems. Consequences are a function of the
total amount of radioactive material in the shipment, the fraction that
escapes from the shipping cask, the fraction of the release from the
shipping cask that is aerosolized, the fraction of the release that is
respirable, the dispersal of radioactive material to humans, and the
characteristics of the exposed population. The NRC staff used the
shipping distances and population distribution information for the
regions pertaining to the sites used for the evaluation of the impacts
of incident-free transportation for accident impact evaluations. The
NRC staff used the most recent available data on accident rates,
release fractions, aerosolized fractions, and respirable fractions in
this evaluation.
The transportation impact evaluation includes the use of the NRC
maintained NRC-Radioactive Material Transport (NRC-RADTRAN)
transportation risk code package, pertinent fuel radionuclide inventory
(source term) data, and external and accidental release
characteristics, routing distance information, and population density
by State along the route. The staff obtained routing information by
running the Web-Based Transportation Routing Analysis Geographic
Information System (WebTRAGIS) code. While the population density
considered in WebTRAGIS is for the year 2012, based in part on the 2010
U.S. Census data, the staff extrapolated the population density to 2022
based on each State's growth rate using 2010 and 2020 U.S. Census data.
The staff compiled information with respect to vehicle daily traffic
count, vehicle speed, vehicle accident, fatality, and injury rates from
U.S. Department of Transportation data base and used that information
in the NRC-RADTRAN analysis to determine single shipment impacts. To
determine annual transportation impacts, the staff applied the
normalized (annual) truck shipments of 52 shipments and 30 shipments
estimated spent ATF from a BWR and PWR, respectively.
The NRC staff found the maximum normal conditions (i.e., incident-
free) cumulative worker dose per year was bounded by the 4 person-rem
value of Table S-4. This worker dose would be managed with multiple
drivers available as the transportation crew so that the individual
worker dose would be below the U.S. Department of Energy administrative
limit of 2 rem per year and the NRC's occupational exposure annual
limit of 5 rem per year. PWR shipment cumulative public doses were at
or slightly higher than the 3 person-rem per year specified in the
Table S-4. The NRC staff found the cumulative population dose per year
for the BWR shipments to be higher than 3 person-rem per year. However,
both the BWR and PWR results are not significant when the related
average individual dose is considered. Namely, the average individual
doses along all routes and fuel types are well below 1 mrem per year, a
small fraction of the average annual natural background radiation
exposure of approximately 310 mrem, and within the Table S-4 range of
doses to exposed individuals. These results are conservative because
they are based on the transport package with the least capacity.
Applying a transport package with a greater capacity would reduce the
number of shipments resulting in a lower cumulative dose that would be
less than the 3 person-rem of Table S-
[[Page 60510]]
4 as shown by the rail sensitivity case in this study (e.g., the GA-4
truck spent fuel transport can hold four PWR fuel assemblies, which
would reduce the PWR cumulative doses by a factor of 4).
The NRC staff found total accidental population risk per year due
to transport of spent ATF, including spent ATF with increased
enrichment and higher burnup levels, continued to demonstrate the low
risks from both radiological and nonradiological accidents and is
consistent with past transportation studies. The greater risk to a
member of the public would be physical harm from an actual vehicle
collision involving a spent ATF shipment, if such an event ever
happens. While the nonradiological risk is the greater risk, the
results of this study demonstrate that those risks would still not be
significant and are less than the common (nonradiological) cause
environmental risks of Table S-4. The results for spent ATF with
increased enrichment and higher burnup are consistent with the
environmental impacts associated with the transportation of fuel and
radioactive wastes to and from current-generation reactors presented in
Table S-4 of 10 CFR 51.52.
Based on the results of the impact analysis, shipment of near-term
ATF technologies with enrichments of up to 8 (wt%) uranium-235 (U-235)
and higher burnup levels of up to 80 gigawatt days per metric ton of
uranium (GWd/MTU) would not significantly change the potential impacts
of either incident-free or accident transportation risk. Hence, the
transportation impacts of spent ATF are bounded by Table S-4.
Therefore, the results of this analysis could serve as a reference in
helping to address the environmental impacts of ATF licensing without a
detailed site-specific transportation analysis, as long as the ATF is
within the enrichment and burnup levels with the associated fuel
assembly radionuclide inventory and parameters applied in the analyses
of this proposed NUREG.
In the case of decommissioning, the expected impacts from
deployment and use of ATF with increased enrichment and higher burnup
levels would be the same as or slightly less than those from
decommissioning nuclear power plants operating with the existing fuel.
Additionally, the expected Decommissioning GEIS and guidance updates
could build upon the analysis from this study to specifically address
the decommissioning of a LWR deploying and using ATF.
Therefore, based on findings in this study, the NRC staff concludes
that the reevaluated findings addressing near-term ATF technologies
(i.e., coated cladding, doping, and FeCrAl cladding) indicate the
environmental effects associated with deploying and using ATF would be
bounded by the NRC staff's prior analysis with enrichments up to 8 wt%
U-235 and extending peak-rod burnup to 80 GWd/MTU for the uranium fuel
cycle, transportation of fuel and waste, and decommissioning.
Additionally, if in a future licensing action, the enrichment and
burnup levels are greater than 8 wt% U-235 and 80 GWd/MTU,
respectively, and for the deployment and use of long-term ATF
technologies, the study could provide guidance for completing the
needed revised analysis.
As the NRC staff continues to prepare to review license
applications related to ATF technologies and fuel with increased
enrichment and higher burnup levels, the NRC staff will evaluate new
industry developments and other activities before publishing the final
NUREG to consider further refinements of the ATF environmental
evaluation. For example, such new information could include results
from ongoing licensing actions regarding the use of higher enrichment
levels in fuel fabrication (ADAMS Accession No. ML22175A070).
III. Specific Requests for Comments
The NRC is seeking advice and recommendations from the public on
the draft NUREG. We are particularly interested in comments and
supporting rationale from the public on the following:
Transportation Accident Release Fractions
1. Previous transportation accident analyses have relied upon the
use of release fractions in Table 7.31 from NUREG/CR-6672,
``Reexamination of Spent Fuel Shipment Risk Estimates,'' (ADAMS
Accession No. ML003698324) for burnup levels up to 60 GWd/MTU. By
subjecting LWR nuclear fuel to higher burnup levels, the radionuclide
inventory available to be released is greater and material issues such
as cladding embrittlement, fuel fragmentation, and additional
diffusional release of fission products are expected to result in
greater release fractions than assessed in NUREG/CR-6672. Therefore,
Appendix B of the draft NUREG assessed the potential effects due to
higher radiological material release fractions from the physical
effects of higher burnup levels on the fuel pin cladding and the
uranium fuel pellets.
The NRC is seeking comment on the use of release fractions
developed in Appendix B of the draft NUREG for higher burnup levels
than previously considered under transportation accident conditions.
Dated: August 29, 2023.
For the Nuclear Regulatory Commission.
John M. Moses,
Deputy Director, Division of Rulemaking, Environmental, and Financial
Support, Office of Nuclear Materials Safety, and Safeguards.
[FR Doc. 2023-18966 Filed 8-31-23; 8:45 am]
BILLING CODE 7590-01-P