[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]


-----------------------------------------------------------------------

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.

-----------------------------------------------------------------------

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