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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
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: April 11, 2002 (Volume 67, Number 70)]
[Notices]
[Page 17725-17728]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11ap02-105]
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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
pdr@nrc.gov.
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]
BILLING CODE 7590-01-P