[Federal Register Volume 67, Number 70 (Thursday, April 11, 2002)]
[Notices]
[Pages 17725-17728]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-8792]


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NUCLEAR REGULATORY COMMISSION

[Docket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457]


Exelon Generation Company, LLC; Byron Station, Unit Nos. 1 AND 2, 
Braudwood Station, Unit Nos. 1 AND 2; Environmental Assessment and 
Finding of No Significant Impact; Related to a Proposed License 
Amendment to Revise Fuel Centerline Temperature Satety Limit

    The U.S. Nuclear Regulatory Commission (NRC) is considering 
issuance of an amendment for Facility Operating License Nos. NPF-37, 
NPF-66, NPF-72, and NPF-77, issued to Exelon Generation Company, LLC, 
(Exelon or the licensee), for operation of the Byron Station, Unit Nos. 
1 and 2, located in Ogle County, Illinois and Braidwood Station, Unit 
Nos. 1 and 2, located in Will County, Illinois. Therefore, as required 
by 10 CFR 51.21, the NRC is issuing this environmental assessment and 
finding of no significant impact.

Environmental Assessment

Identification of Proposed Action

    The proposed action would revise the reactor core safety limit for 
peak fuel centerline temperature from less than or equal to 4700  deg.F 
to the design-basis fuel centerline melt temperature of less than 5080 
deg.F, for unirradiated fuel, decreasing by 58  deg.F per 10,000 
Megawatt-Days per Metric Tonne

[[Page 17726]]

Uranium (MWD/MTU) burnup. The increase in the fuel centerline 
temperature limit is to accommodate higher burnup of these fuel rods to 
exceed the licensing basis commitment rod-average burnup limit. The 
licensee requested that the licensing basis commitment limiting the 
fuel rod-average burnup to 60,000 MWD/MTU be revised to increase the 
rod-average burnup limit for only high burnup lead test assemblies 
(LTAs) to 69,000 MWD/MTU for Byron, Unit 2 Cycle 10, and 75,000 MWD/MTU 
for both stations for future campaigns. The burnup limits are not part 
of the technical specifications, but are limited by the fuel centerline 
temperature.
    The proposed action is in accordance with the licensee's 
application dated September 21, 2001, as supplemented by letter dated 
January 31, 2002, requesting NRC to provide an amendment to the 
technical specification (TS) for Byron Station, Units 1 and 2, and 
Braidwood Station, Units 1 and 2.

The Need for the Proposed Action

    Two LTAs are currently in use in Byron, Unit 2, Cycle 10. These 
LTAs are composed of low-tin ZIRLO cladding and fuel pin spring clips, 
and higher density fuel pellets. Additionally, one of the LTAs was 
modified to include four fuel rods which have been previously burned 
during two cycles to 45,750 MWD/MTU. Following irradiation during a 
third cycle, the four rods will have a projected burnup of 
approximately 69,000 MWD/MTU. Irradiation of these four fuel rods to a 
higher burnup will provide data on fuel and materials performance that 
will support industry goals of extending the current fuel burnup limits 
and will provide data to address NRC questions related to fuel 
performance behavior at high burnups. The data will also help confirm 
the applicability of nuclear design and fuel performance models at high 
burnups.
    The proposed irradiation of this fuel assembly does not require a 
change to the TS. However, the planned additional cycle of operation 
for the high burnup fuel rods will result in burnup levels exceeding 
the rod-average burnup limit of 60,000 MWD/MTU for that LTA (which is 
the design limit for the use of Zircaloy or ZIRLO clad fuel in Byron 
and Braidwood approved in amendments 78 and 70 respectively).

Environmental Impacts of the Proposed Action

Background

    In its previous environmental assessments concerning fuel burnup, 
the Commission relied on the results of a study conducted by the NRC by 
Pacific Northwest National Laboratories (PNNL). The results of the 
study were documented in detail in the report, ``Assessment of the Use 
of Extended Burnup Fuels in Light Water Power Reactors'' (NUREG/CR-
5009, PNL-6258, February 1988). The overall findings of this study 
showed there were no significant adverse effects generated by 
increasing the batch-average burnup level of 33,000 MWD/MTU to 50,000 
MWD/MTU or above as long as the maximum rod average burnup level of any 
fuel rod was no greater than 60,000 MWD/MTU. Furthermore, based on the 
above study and the report, ``The Environmental Consequences of Higher 
Fuel Burn-up,'' (AIF/NESP-032), issued by the Atomic Industrial Forum, 
the NRC staff concluded that the environmental impacts summarized in 
Table S-3 of 10 CFR 51.51 and in Table S-4 of 10 CFR 51.52 for a burnup 
level of 33,000 MWD/MTU are conservative and bound the corresponding 
impacts for burnup levels up to 60,000 MWD/MTU and uranium-235 
enrichments up to 5 percent by weight.\1\
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    \1\ See ``Exended Burmup Fuel Use in Commercial LWRs; 
Environmental Assessment and Finding of No Significant Impact,'' 53 
FR 6040, February 29, 1988.
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    In this environmental assessment regarding the impacts of the use 
of extended burnup fuel beyond 60,000 MWD/MTU, the Commission is 
relying on the results of another study conducted for it by PNNL 
entitled, ``Environmental Effects of Extending Fuel Burnup Above 60 
GWd/MTU,'' (NUREG/CR-6703, PNL-13257, January 2001). This report 
represents an update to NUREG/CR-5009. Although the study evaluated the 
environmental impacts of high burnup fuel up to 75,000 MWD/MTU, certain 
aspects of the review were limited to evaluating the impacts of 
extended burnup up to 62,000 MWD/MTU because of data available to 
support these findings. During the study, all aspects of the fuel-cycle 
were considered, from mining, milling, conversion, enrichment and 
fabrication through normal reactor operation, transportation, waste 
management, and storage of spent fuel.

Environmental Impacts

    The NRC has completed its evaluation of the proposed action and 
concludes that there are no significant environmental impacts 
associated with irradiation of the four fuel rods in assembly M09E to a 
burnup of 69,000 MWD/MTU. The following is a summary of the staff's 
evaluation:
    The extended burnup rods in the LTA will have a different 
radionuclide mix than the rest of the core. The activities of short-
lived fission products will tend to remain constant or decrease 
slightly, while activities associated with activation products and 
actinides tend to increase with increasing burnup. As discussed in 
Attachment D to the September 21, 2001, amendment request, although 
there are variations in core inventories of isotopes due to extended 
burnup, there are no significant increases of isotopes that are major 
contributors to accident doses. In addition, the four fuel rods in the 
LTA will only contribute a very small variation in the isotopic 
population of the core. Thus, with extended burnup of the LTA, no 
significant increase in the release of radionuclides to the environment 
is expected during normal operation. In addition, no change is being 
requested by Exelon in the licensed technical specifications pertaining 
to allowed cooling-water activity concentrations. If leakage of 
radionuclides from the extended burnup LTA occurs during operation, 
then the radioactive material is expected to be removed by the plant 
cooling water cleanup system.
    As discussed in Attachment D to the September 21, 2001, amendment 
request, the proposed changes will not result in changes in the 
operation or configuration of the facility. There will be no change in 
the level of controls or methodology used for processing radioactive 
effluents or handling solid radioactive waste, nor will the proposal 
result in any change in the normal radiation levels within the plant. 
Accordingly, the impacts on workers and the general population would 
not be significant because of the small radiological effect of the four 
extended burnup rods in the LTA.

Environmental Impacts of Potential Accidents

    Accidents that involve the damage or melting of the fuel in the 
reactor core and spent-fuel handling accidents were also evaluated in 
NUREG/CR-6703. The accidents considered were a loss-of-coolant accident 
(LOCA), a steam generator tube rupture, and a fuel-handling accident.
    For LOCAs, an appreciable amount or all of the fuel melts and a 
portion of the fission products and aerosols are released from the 
containment system

[[Page 17727]]

into the biosphere. The increase in the consequences of a postulated 
LOCA are not appreciable because of the small number of rods exceeding 
60,000 MWD/MTU.
    The pressurized-water reactor (PWR) steam generator tube rupture 
accident involves direct release of radioactive material from the 
contaminated reactor coolant to the environment. As discussed 
previously, no change is being requested by Exelon in the licensed 
technical specifications pertaining to allowed cooling-water activity 
concentrations. The maximum coolant activity is regulated through 
technical specifications that are independent of fuel burnup. This 
accident scenario has been addressed acceptably by the licensee, and 
the consequences have been determined to comply with the Commission's 
regulations.
    The scenario used in evaluating potential fuel-handling accidents 
involves a direct release of gap activity to the environment. The gap 
activity of concern is based on guidance in Regulatory Guide 1.183, 
``Alternative Radiological Source Terms for Evaluating Design Basis 
Accidents at Nuclear Power Reactors,'' and NUREG-1465, ``Accident 
Source Terms for Light-Water Nuclear Power Plants,'' and consists 
primarily of the noble gases, iodines, and cesiums. The only isotopes 
that contribute significant fractions of the committed effective dose 
equivalent and thyroid doses are \131\I and \134\Cs. Similarly, the 
only isotopes that contribute significant fractions of the deep dose 
are \132\I and \133\Xe. Even though the iodine inventory decreases with 
increasing burnup, the potential doses from fuel-handling accidents 
increase with fuel burnup because of increased gap-release fraction. 
However, because of the small number of rods exceeding 60,000 MWD/MTU, 
the staff concludes that the dose resulting from a fuel-handling 
accident involving the LTA would remain below regulatory limits.

Environmental Impacts of Transportation

    The environmental effects of incident-free spent fuel 
transportation were also evaluated in NUREG/CR-6703. Incident-free 
transportation refers to transportation activities in which the 
shipments of radioactive material reach their destination without 
releasing any radioactive cargo to the environment. The vast majority 
of radioactive shipments are expected to reach their destination 
without experiencing an accident or incident, or releasing any cargo. 
The incident-free impacts from these normal, routine shipments arise 
from the low levels of radiation that are emitted externally from the 
shipping container. Although Federal regulations in 10 CFR Part 71 and 
49 CFR Part 173 impose constraints on radioactive material shipments, 
some radiation penetrates the shipping container and exposes nearby 
persons to low levels of radiation. Based on the realistic analysis 
presented in NUREG/CR-6703, the staff concludes that doses associated 
with incident-free transportation of spent fuel with burnup to 75,000 
MWD/MTU are bounded by the doses given in 10 CFR 51.52, Table S-4, for 
all regions of the country if dose rates from the shipping casks are 
maintained within regulatory limits.
    Additionally, the environmental effects of spent fuel 
transportation accidents were also evaluated in NUREG/CR-6703. 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 consequences of such a 
transportation accident 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. The 
consequences are a function of the total amount of radioactive material 
in the shipment, the fraction that escapes from the shipping cask, the 
transport of radioactive material to humans, and the characteristics of 
the exposed population. Considering the uncertainties in the data and 
computational methods, the overall changes in transportation accident 
risks due to increasing fuel burnup of the four fuel rods in the LTA 
are not significant. Because of the small number of rods exceeding 
60,000 MWD/MTU in the LTA, the doses resulting from a spent fuel 
transportation accident will remain below regulatory limits, and no 
significant increase in the environmental effects of spent-fuel 
transportation accidents are expected.

Non-Radiological Impacts

    With regard to potential non-radiological impacts, the proposed 
action does not have a potential to affect any historic sites. It does 
not affect non-radiological plant effluents and has no other 
environmental impact. Therefore, there are no significant non-
radiological environmental impacts associated with the proposed action.

Summary

    Based on the staff's independent assessment discussed above, the 
NRC concludes that there are no significant adverse environmental 
impacts associated with the increase to the fuel centerline temperature 
limit and the irradiation of the four fuel rods to a burnup of 69,000 
MWD/MTU.

Environmental Impacts of the Alternatives to the Proposed Action

    As an alternative to the proposed action, the staff considered 
denial of the proposed action (i.e., the ``no action'' alternative). 
Denial of the application would result in no change in current 
environmental impacts. The environmental impacts of the proposed action 
and the alternative action are similar. However, it would deny to the 
licensee and the NRC operational data on the performance of fuel at 
extended burnup conditions.

Alternative Use of Resources

    The action does not involve the use of any different resources than 
those previously considered in the Final Environmental Statement for 
the Byron Station, Unit Nos. 1 and 2 (dated April 30, 1982), and 
Braidwood Station, Unit Nos. 1 and 2 (dated June 30, 1984).

Agencies and Persons Consulted

    On March 20, 2002, the staff consulted with the Illinois State 
official, Mr. Joe Brittin, of the Illinois Department of Nuclear 
Safety, regarding the environmental impact of the proposed action. The 
State official had no comments.

Finding of No Significant Impact

    On the basis of the foregoing environmental assessment, the NRC 
staff concludes that permitting a change to the fuel centerline 
temperature, which would, in turn, permit irradiation of the four fuel 
rods to a burnup of 69,000 MWD/MTU, will not have a significant effect 
on the quality of the human environment. Accordingly, the NRC has 
determined not to prepare an environmental impact statement for the 
proposed action.
    For further details with respect to the proposed action, see the 
licensee's letter dated September 21, 2001, as supplemented by letter 
dated January 31, 2002. Documents may be examined, and/or copied for a 
fee, at the NRC Public Document Room, located at One White Flint North, 
11555 Rockville Pike (first floor), Rockville, Maryland. Publicly 
available records will be accessible electronically from the ADAMS 
Public Library component of NRC's Web site, http://www.nrc.gov (the 
Public Electronic Reading Room). If you do not have access to ADAMS or 
if there are problems in accessing the

[[Page 17728]]

documents located in ADAMS, contact the NRC Public Document Room (PDR) 
Reference staff at 1 (800) 397-4209, or (301) 415-4737, or by e-mail to 
[email protected].

    Dated at Rockville, Maryland, this 5th day of April, 2002.

    For the Nuclear Regulatory Commission.
Anthony J. Mendiola,
Chief, Section 2, Project Directorate III, Division of Licensing 
Project Management, Office of Nuclear Reactor Regulation.
[FR Doc. 02-8792 Filed 4-10-02; 8:45 am]
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