[Federal Register Volume 66, Number 213 (Friday, November 2, 2001)]
[Notices]
[Pages 55703-55709]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-27716]
[[Page 55703]]
=======================================================================
-----------------------------------------------------------------------
NUCLEAR REGULATORY COMMISSION
[Docket No. 50-331]
Nuclear Management Company, LLC; Duane Arnold Energy Center
Environmental Assessment and Finding of No Significant Impact Related
to a Proposed License Amendment To Increase the Maximum Rated Thermal
Power Level
The U.S. Nuclear Regulatory Commission (NRC) is considering
issuance of an amendment to Facility Operating License No. DPR-49,
issued to Nuclear Management Company, LLC (NMC), for operation of the
Duane Arnold Energy Center, located in Linn County, Iowa. Therefore,
pursuant to 10 CFR 51.21 and 10 CFR 51.35, the NRC is issuing this
environmental assessment and finding of no significant impact.
Environmental Assessment
Identification of the Proposed Action
The proposed action would allow NMC, the operator of DAEC, to
incrementally increase its electrical generating capacity by raising
the maximum reactor core power level from 1658 MWt to 1912 MWt, 15.3
percent above the current maximum licensed power level. The change is
considered an EPU for a BWR because it would raise the reactor core
power level more than approximately 7 percent above the original
maximum licensed power level. A previous 4.1-percent power uprate,
implemented in 1985, raised the original maximum power level from 1593
MWt to 1658 MWt. A power uprate increases the heat output of the
reactor to support increased turbine inlet steam flow requirements and
increases the heat dissipated by the condenser to support increased
turbine exhaust steam flow requirements.
The proposed action is in accordance with NMC's application for
amendment dated November 16, 2000, as supplemented April 16 (two
letters) and 17; May 8 (two letters), 10, 11 (two letters), 22, and 29;
June 5, 11, 18, 21, and 28; July 11, 19, and 25; and August 1, 10, 16,
and 21; and October 17, 2001, and NMC's ``Supplement to DAEC
Environmental Report,'' submitted on September 22, 2000, in advance of
the application.
The NRC previously published a draft environmental assessment of
the proposed action in the Federal Register (66 FR 48482, September 20,
2001) and offered an opportunity for public comment. No comments were
received.
Need for the Proposed Action
Alliant Energy--IES Utilities (Alliant), the principal owner of
DAEC,\1\ has compared the projected load growth to its electrical
generating capacity and has determined a need for additional capacity
in its territory. Alliant's obligated capacity is expected to increase
by 2 percent per year. The proposed EPU would add 80 megawatts of
electrical generating capacity to the grid. The estimated cost of
adding this generating capacity is approximately half the cost of
purchasing power and one-third the cost of providing the power by
constructing a new combined-cycle, natural-gas-fueled facility.
Therefore, Alliant concluded that increasing DAEC's capacity would be
the most economical option for increasing power supply. Furthermore,
unlike fossil fuel plants, DAEC does not routinely emit sulfur dioxide,
nitrogen oxide, carbon dioxide, or other atmospheric pollutants.
---------------------------------------------------------------------------
\1\ On January 10, 2001, the NRC published in the Federal
Register (66 FR 2009) an Environmental Assessment and Finding of No
Significant Impact regarding a requested change to the DAEC
operating license to reflect the proposed change in the owner's name
from IES Utilities, Inc., to Interstate Power and Light Company. The
NRC's final action regarding the requested name change is pending.
---------------------------------------------------------------------------
Environmental Impacts of the Proposed Action
At the time of the issuance of the operating license for DAEC, the
NRC staff noted that any activity authorized by the license would be
encompassed by the overall action evaluated in the Final Environmental
Statement (FES) for the operation of DAEC, which was issued in March
1973. The original operating license for DAEC allowed a maximum reactor
power level of 1593 MWt. On September 22, 2000, NMC submitted a
supplement to its Environmental Report supporting the proposed EPU
action and provided a summary of its conclusions concerning the
environmental impacts of the proposed action. Based on the NRC staff's
independent analyses of the nonradiological and radiological impacts
and the evaluation performed by the licensee, the staff has concluded
that the environmental impacts of the EPU are bounded by the
environmental impacts previously evaluated in the FES because the EPU
does not involve extensive changes to plant systems that directly or
indirectly interface with the environment. Additionally, the licensee
states that no changes to the National Pollutant Discharge Elimination
System permit issued by the State would be necessary.
Nonradiological Impacts
The following is the NRC staff's evaluation of the nonradiological
environmental impacts of the EPU on land use, water use, waste
discharges, terrestrial and aquatic biota, transmission facilities, and
social and economic conditions at DAEC.
Land Use Impacts
The proposed EPU would not modify the land use at the site, nor
have any impacts on lands with historic or archaeological significance.
The licensee states that it has no plans to construct any new
facilities or alter the land around existing facilities, including
buildings, access roads, parking facilities, laydown areas, onsite
transmission and distribution equipment, or power line rights-of-way,
in conjunction with the EPU. The EPU would not significantly affect the
storage of materials, including chemicals, fuels, and other materials
stored above or under the ground. The EPU would not alter the
aesthetics of the site. Therefore, the FES conclusions for impacts on
land use would remain valid under EPU conditions.
Water Use Impacts
The staff evaluated surface water use and groundwater use as
environmental impacts of water usage at DAEC.
Surface Water Use
An EPU is accomplished by increasing the heat output of the
reactor, thereby increasing the steam flow to the turbine, for which
increased feedwater flow is needed. The increased heat load on the
cooling tower would cause evaporative losses to increase; therefore,
cooling tower makeup to the circulating water system increases to
compensate for the increase in evaporative losses. Cooling tower makeup
at DAEC is supplied by the Cedar River and well water systems. The EPU
would not change the amount of water withdrawn from the well water
system. The EPU would require an increase in river water use; however,
the licensee stated that DAEC would not use more river water than
permitted. In accordance with the water appropriation limits of the
Iowa Department of Natural Resources (IDNR), DAEC may withdraw a
maximum of 12,575 million gallons per year (MGY) from the Cedar River
at a rate of 27,000 gallons per minute (gpm) minus the total well water
withdrawal rate (3000 gpm). Special operating restrictions apply at
lower-than-average river flows if the withdrawal would reduce the river
flow to less than 500 cubic feet per second (cfs). A maximum flow rate
of 11,000 gpm and an annual
[[Page 55704]]
withdrawal rate of 5782 MGY were analyzed in the FES. During the years
1996 through 1999, the flow at DAEC averaged 5680 gpm. The licensee
predicts the flow will be 6700 gpm under EPU conditions. The predicted
flow average under EPU conditions is approximately 40 percent less than
that analyzed in the FES and is below the IDNR-permitted limits. In the
period 1996-1999, the annual withdrawal rate at DAEC averaged 3000 MGY;
the licensee projects it will be 3540 MGY under EPU conditions. The
3540 MGY projected average flow withdrawal rate is also below the value
evaluated in the FES and the IDNR-permitted limit of 12,575 MGY. The
EPU would have no impact on the number of cooling tower concentration
cycles or on the cooling tower flow rate. Therefore, current water
appropriation limits would be maintained and the conclusions in the FES
would remain valid under the proposed EPU conditions.
Groundwater Use
The staff evaluated the consumption of groundwater as an
environmental impact of the proposed EPU. Groundwater use at DAEC is
governed by a permit issued by the IDNR. The permit limits DAEC to 1575
MGY with the flow from all pumps not to exceed 3000 gpm. A maximum flow
rate of 1500 gpm and a withdrawal rate of 788 MGY were evaluated in the
FES. The average annual groundwater withdrawal rate for DAEC is 762
MGY, with a normal system flow averaging 1420 gpm.
The licensee stated that the proposed EPU would not increase the
consumption of groundwater, would not impact the well water system flow
path, and does not require any additional cooling capacity from the
groundwater in order to shed heat loads. Therefore, the staff's
conclusions in the FES on groundwater use are valid for the proposed
EPU.
Discharge Impacts
The staff evaluated environmental impacts such as cooling tower
fogging, icing, drift, noise, chemical discharges to surface water,
sanitary waste discharges, blowdown, thermal plume spread, temperature
of the river water, cold shock to aquatic biota, hazardous waste
effluents, and air emissions.
Cooling Tower Fogging, Icing, Drift, and Noise
Environmental impacts such as fogging, icing, cooling tower drift,
and noise could result from the increased heat load on the cooling
tower under EPU conditions. In the FES, the staff concluded that the
operation of the DAEC cooling towers may slightly increase fogging and
icing in nearby areas. The staff stated that cooling tower drift was
estimated to be a maximum of 0.1 percent of cooling water flow, or 0.65
cubic feet per second (290 gpm). The estimates were based on
anticipated evaporation and drift rates of 2.25 percent and 0.5 percent
of tower flow, respectively. The licensee stated that the total hours
of fogging would increase by approximately 1.1 hour per year above the
nominal 240 hours per year, and that icing would be insignificant. The
proposed EPU would not change the cooling tower flow or drift rate;
however, the evaporation rate was calculated to increase to
approximately 3 percent.
Since the original analysis in the FES, the cooling towers at DAEC
have been upgraded by replacing the wooden drift eliminators with
polyvinyl chloride (PVC) drift eliminators. The PVC drift eliminators
allow water droplets to return to the cooling tower air stream and
channel water to the cooling tower's cold water basin, which reduces
evaporation and drift losses. Consequently, the licensee's analysis of
the effect of the EPU on fogging is conservative.
After considering the increase in heat load on the cooling towers,
the staff concluded that the incremental effects of fog attributable to
the proposed EPU would be negligible and would continue to be bounded
by the FES. Other cooling tower impacts, such as drift and icing, would
not be expected to change as a result of the EPU. Therefore, the staff
finds that the conclusions in the FES for fogging, icing, and cooling
tower drift would be valid under the proposed EPU conditions.
The FES also stated that the operation of the cooling towers would
result in a noticeable, but acceptable, increase in the noise level at
the nearest dwelling. The proposed EPU would not significantly change
the character, sources, or energy of noise generated at DAEC. The new
equipment necessary to implement the EPU would be installed within
existing plant buildings and no significant increase in ambient noise
levels within the plant would be expected. Therefore, the FES
conclusions for noise levels would remain valid under EPU conditions.
Chemical and Sanitary Discharges
Surface water and wastewater discharges are regulated by the State
of Iowa. The National Pollutant Discharge Elimination System (NPDES)
permit is periodically reviewed and reissued by the IDNR. The present
NPDES permit for DAEC authorizes discharges from two outfalls, only one
of which would be affected by the EPU.
The use of chemicals and their subsequent discharge to the
environment would not be expected to change significantly as a result
of the proposed EPU. The cooling tower concentration cycle would remain
within the current range of 3.5 to 4.0. Therefore, the concentration of
pollutants in the effluent stream would remain the same. No changes to
the sanitary waste systems or to the parameters regulated by the NPDES
permit would be needed to accomplish the EPU. Sanitary waste from DAEC
is discharged directly to the DAEC sewage treatment plant in accordance
with a permit from the State of Iowa.
Blowdown
Total discharge would increase linearly with blowdown flow. It is
anticipated that the blowdown flow would increase 18 percent as a
result of the EPU. Blowdown for the circulating water system is
discharged into the Cedar River. The FES conservatively assumed a
blowdown flow rate of 4000 gpm. The actual blowdown flow rate is 1570
gpm and the blowdown flow rate calculated for EPU conditions would be
1850 gpm. During winter, the season which DAEC discharges would have
the greatest impact on river water temperature, the actual average
blowdown temperature is 30 degrees Fahrenheit ( deg.F) less than that
assumed in the FES. The EPU would increase the blowdown discharge
temperature by approximately 1.6 deg.F. Typical discharge temperatures
and flow rates are below the current limits so it would not be
necessary to modify the NPDES permit to implement the proposed EPU.
Thermal Plume Spread and Temperature of River Water
The actual average blowdown flow rate is 1,570 gpm. The FES assumed
a value of 4,000 gpm. The increased values for uprated power blowdown
temperature and flow are still bounded by the calculation of the FES.
Consequently, the FES conclusions remain valid. The FES concluded that
the thermal plume would be less than 1 acre in area and would reach
less than a quarter of the reach across the river. The EPU would
increase the discharge temperature by 1.6 deg.F and the flow rate by
18 percent. However, the EPU would not noticeably increase the plume
size.
Under worst-case winter conditions, the 2 deg.F isotherm was
predicted to extend about 250 feet downstream with a width of about 70
feet. A discharge temperature of 72 deg.F for the month of
[[Page 55705]]
January was analyzed in the FES. Historically, in winter, when
discharges would have the greatest impact on river water temperature,
the actual average blowdown temperature is 30 deg.F less than that
assumed in the FES. The average discharge temperature (from 1961 to
1990) for the month of January was 36 deg.F, and, as stated above, the
EPU would increase the discharge temperature by only 1.6 deg.F.
Consequently, the actual size of the thermal plume is smaller than
predicted in the FES.
Under worst-case summer conditions, with the same assumptions and
data used to calculate the circulating water discharge temperature, the
2 deg.F isotherm was predicted to extend about 75 feet downstream of
the discharge point with a width of about 35 feet. Thermal mapping
conducted in August 1989, demonstrated the conservative nature of the
assumptions in the FES. The mapping was performed at 100-percent
reactor power. The 2 deg.F isotherm extended to between 100 and 150
feet downstream, and was restricted to within 10 feet of the bank (i.e.
10 feet wide). At 150 feet downstream, there was no detectible plume.
The total plume area was less, therefore, than that predicted for the 2
deg.F isotherm in the FES, and, as stated above, the EPU would not
noticeably increase the plume size. The staff concludes the plumes for
both summer and winter cases are bounded by the FES. The conditions
analyzed in the FES would be expected to remain valid under the
proposed EPU conditions.
Cold Shock
Cold shock to an aquatic biota occurs when the warm water discharge
from a plant abruptly stops because of an unplanned shutdown, resulting
in a temperature drop of the river water and the possible adverse
impact on aquatic biota. The probability of an unplanned shutdown is
independent of a power uprate. As discussed previously, the discharge
canal temperature at EPU conditions would be at least 10 deg.F less
than the value evaluated in the FES. Additionally, the plume size would
not increase appreciably under power uprate conditions and would be
smaller than analyzed in the FES. Therefore, the risk of aquatic biota
mortality by cold shock would continue to be bounded by the conclusions
in the FES.
Hazardous Waste Generation and Air Emissions
Hazardous waste generated from routine plant operations and air
emissions from the plant heating boiler and diesel generators are
controlled by county permits. A power uprate would not have a
significant impact on the quality or quantity of effluents from these
sources, and operation under EPU conditions would not reduce the margin
to the limits established by the applicable permits. Therefore, the
conclusions in the FES would remain valid.
Terrestrial Biota Impacts
The proposed EPU would not result in a land disturbance that could
adversely impact the habitat of any terrestrial plant or animal
species. The licensee stated that according to a recent review by the
IDNR, there were no known rare or endangered terrestrial species within
the area of the site boundary. Additionally, the licensee stated that
land use would remain the same as evaluated in the FES. Therefore, the
staff's conclusions in the FES about the impact on terrestrial ecology,
including endangered and threatened plant and animal species, would
remain valid for the proposed EPU.
Aquatic Biota Impacts
The impacts of operation of the river water intake include
impingement of fish on the traveling screens at the intake structure
and the entrainment of benthic organisms. The losses associated with
the impingement and entrainment of organisms were assessed in the FES
and were judged to be insignificant. The effect of the EPU on the
impingement and entrainment of organisms also would be insignificant.
Fish impingement totals are typically less than 500 fish per year and
are considered to be very low, considering the size and composition of
the fish population in the Cedar River. Additionally, the licensee
stated that there were no known rare or endangered aquatic species in
the plant site vicinity. Therefore, the staff's conclusions in the FES
as to impingement, entrainment, and endangered and threatened aquatic
species would remain valid for the proposed EPU.
Transmission Facility Impacts
Environmental impacts, such as exposure to electromagnetic fields
(EMFs) and shock could result from a major modification to transmission
line facilities. However, the licensee stated that no change would be
made to the existing transmission line design or operation as a result
of the proposed EPU. Higher main transformer capacity would be
necessary to deliver the additional power to the offsite grid and
certain modifications to offsite substations are being planned to
enhance stability at various grid locations. These modifications are
consistent with Alliant's program of systematic improvements in grid
stability and its commitments to the Mid-Continent Area Power Pool and
the Mid-America Interconnected Network; modifications would be
performed within existing substations. Therefore, no significant
environmental impacts from any changes in transmission facilities
design and equipment are expected, and the conclusions in the FES would
remain valid.
The rise in generator output associated with EPU would slightly
increase the current and the EMFs in the onsite transmission line
between the main generator and the plant substation. The line is
located entirely within the fenced, licensee-controlled boundary of the
plant, and neither members of the public nor wildlife are expected to
be affected. Exposure to EMFs from the offsite transmission system is
not expected to increase significantly and any such increase is not
expected to change the staff's conclusion in the FES that no
significant biological effects are attributable to EMFs from high
voltage transmission lines.
DAEC transmission lines are designed and constructed in accordance
with the applicable shock prevention provisions of the National
Electric Safety Code and the EPU would not cause the transmission line
design to deviate from the NESC provisions. Therefore, the slight
expected increase in current attributable to the proposed EPU does not
change the staff's conclusion in the FES that adequate protection is
provided against hazards from electrical shock.
Social and Economic Impacts
The staff has reviewed information provided by the licensee
regarding socioeconomic impacts, including possible impacts on the DAEC
workforce and the local economy. DAEC employs more than 500 people and
is a major contributor to the local tax base. DAEC personnel also
contribute to the tax base by paying sales and property taxes. The
proposed EPU would not significantly affect the size of the DAEC
workforce and would have no material effect on the labor force required
for future outages. Because the plant modifications needed to implement
the EPU would be minor, any increase in sales taxes and local and
national business revenues would be negligible relative to the large
taxes paid by DAEC. It is expected that improving the economic
performance of DAEC through cost reductions and lower total bus bar
costs per kilowatt hour would enhance the value of DAEC as a generating
asset
[[Page 55706]]
and lower the probability of early plant retirement. Early plant
retirement might have a negative impact upon the local economy and the
community as a whole by reducing public services, employment, income,
business revenues, and property values, although these reductions might
be mitigated by decommissioning activities in the short term. The staff
expects that conclusions in the FES regarding social and economic
impacts would remain valid under EPU conditions.
The staff also considered the potential for direct physical impacts
of the proposed EPU, such as vibration and dust from construction
activities. The proposed EPU would be accomplished primarily by changes
in station operation and a few physical modifications to the facility.
These limited modifications would be accomplished without physical
changes to transmission corridors, access roads, other offsite
facilities, or additional project-related transportation of goods or
materials. Therefore, no significant additional construction
disturbances causing noise, odors, vehicle exhaust, dust, vibration, or
shock from blasting are anticipated, and the conclusions in the FES
would remain valid.
Summary
In summary, the proposed EPU would not result in a significant
change in nonradiological impacts on land use, water use, waste
discharges, terrestrial and aquatic biota, transmission facilities, or
social and economic factors, and would have no nonradiological
environmental impacts other than those evaluated in the FES.
Table 1.--Summary of Nonradiological Environmental Impacts of an EPU at
DAEC
------------------------------------------------------------------------
------------------------------------------------------------------------
Land Use Impacts............. No change in land use or aesthetics;
would not impact lands with historic or
archeological significance.
Water Use Impacts:
Surface Water Use........ Increase in river water withdrawal rate
to 3540 MGY; withdrawal rate would
remain within permitted levels, and
within levels evaluated in the FES.
Groundwater Use.......... No change in groundwater use.
Discharge Impacts:
Fogging.................. Increase in total hours of fogging per
year by 1.1 hour.
Icing.................... No significant change in icing.
Cooling Tower Drift...... No significant change in cooling tower
drift.
Noise.................... No significant change in noise.
Chemical and Sanitary No expected change to chemical use and
Discharge. subsequent discharge, or sanitary waste
systems; cooling towers would operate in
the current cycle range. No changes to
sanitary waste discharges.
Blowdown................. Increase in blowdown by 18 deg.; blowdown
would remain within the permitted
limits.
Thermal Plume and Temperature No noticeable increase in thermal plume
of the River Water. size. Discharge temperature increase by
1.6 EF; river temperature would remain
within National Pollution Discharge
Elimination System limit of 9 deg.F.
Hazardous Waste and Air No changes to hazardous waste sources or
Emissions. air emissions.
Terrestrial Biota Impacts.... No change in terrestrial biota impacts;
no known threatened or endangered
species within the site boundary.
Aquatic Biota Impacts........ No change in aquatic biota impacts; no
known threatened or endangered species
in the area of surface water intake or
discharge.
Transmission Line Facility No change to transmission line design or
Impacts. operation; higher main transformer
capacity would be needed to deliver
additional power and these changes would
be made within existing substations; no
change in exposure to EMFs.
Social and Economic Impacts.. No significant change in size of DAEC
workforce. Few modifications to physical
station facility. No significant
disturbances from noise, odor, vehicle
exhaust, dust, vibration, or shock would
be expected from construction.
------------------------------------------------------------------------
Radiological Impacts
The staff evaluated radiological environmental impacts on waste
streams, in-plant and offsite doses, accident analyses, and fuel cycle
and transportation factors. The following is a general description of
the waste treatment streams at DAEC and an evaluation of the
environmental impacts.
Radioactive Waste Stream Impacts
DAEC uses waste treatment systems designed to collect, process, and
dispose of radioactive gaseous, liquid, and solid waste in accordance
with the requirements of 10 CFR part 20 and Appendix I to 10 CFR part
50. These radioactive waste treatment systems are discussed in the FES.
The proposed EPU would not affect the environmental monitoring of these
waste streams or the radiological monitoring requirements contained in
licensing basis documents. The proposed EPU would not result in any
changes in operation or design of equipment in the gaseous, liquid, or
solid waste systems. The proposed EPU would not introduce new or
different radiological release pathways and would not increase the
probability of an operator error or equipment malfunction that would
result in an uncontrolled radioactive release. The staff evaluated any
changes in the gaseous, liquid, and solid waste streams for
radiological environmental impact of the proposed EPU, as set forth
below.
Gaseous Radioactive Waste Impacts
During normal operation, the gaseous effluent systems control the
release of gaseous radioactive effluents to the site environs,
including small quantities of noble gases, halogens, particulates, and
tritium, so that routine offsite releases from station operation remain
below the limits of 10 CFR part 20 and appendix I to 10 CFR part 50 (10
CFR part 20 includes the requirements of 40 CFR part 190). The gaseous
waste management systems include the offgas system and various building
ventilation systems. The proposed EPU assumes an increase in the
release rate that is linearly proportional to power increase, and an
increase in gaseous effluents would, therefore, occur. The resultant
effluent increases in noble gas and iodine-131 activity are 0.3 and 4E-
07 microcuries per second, respectively. The staff has evaluated
information provided by the licensee and concludes that the estimated
dose values would be below Appendix I requirements after the EPU. These
dose levels are very small,
[[Page 55707]]
and have no significant impact on human helath. The effluents for noble
gases and effluents are well below those evaluated in the FES.
Therefore, the conclusions in the FES would remain valid under EPU
conditions.
Liquid Radioactive Waste Impacts
The liquid radwaste system is designed to process and recycle (to
the extent practicable) the liquid waste collected so that annual
radiation doses to individuals are maintained below the guidelines in
10 CFR Part 20 and 10 CFR Part 50, Appendix I. DAEC operates as a zero
radioactive liquid release plant. The staff expects no change in the
zero release policy as a result of the proposed EPU.
Filter backwashing provides decanted sludge water into the liquid
radwaste system. Increasing the reactor thermal power by 15 percent
would increase the frequency of backwashing necessary to decant
backwash water from the reactor water cleanup condensate demineralizer
filters by approximately 8 to 10 percent. However, since Alliant
maintains a zero radioactive liquid release to the environment, the
slight increase in flow to the liquid radwaste system would be recycled
instead of discharged.
The EPU conditions would not result in significant increases in the
volume of fluid from other sources flowing into the liquid radwaste
system. The reactor would continue to be operated within its present
pressure control band. Valve packing leakage volume into the liquid
radwaste system is not expected to increase. There would be no changes
in reactor recirculation pump seal flow or the flow of any other normal
equipment drain path. In addition, there would be no impact on the
dirty radwaste or chemical waste subsystems of the liquid radwaste
system as a result of the EPU since the operation and the inputs to
these subsystems are independent of power uprate. Based on information
submitted by the licensee, the staff concludes that no significant dose
increase in the liquid pathway would result from the proposed EPU.
Therefore, the conclusions in the FES would remain valid under EPU
conditions.
Solid Radioactive Waste Impacts
The solid radioactive radwaste system collects, monitors,
processes, packages, and provides temporary storage facilities for
radioactive solid wastes prior to offsite shipment and permanent
disposal. DAEC has implemented procedures to assure that the processing
and packaging of wet and dry solid radioactive waste and irradiated
reactor components are accomplished in compliance with the regulations.
Wet Waste: The largest volume contributors to radioactive solid wet
waste are the spent resin and filter sludges from the process wastes.
Equipment waste from operation and maintenance activities, chemical
wastes, and reactor system wastes also contribute to solid waste
generation. The staff expects that the process wastes generated from
the operation of the reactor water cleanup filter demineralizers and
the condensate demineralizers will increase by no more than 10 percent.
More frequent reactor water cleanup backwashes are anticipated under
EPU conditions due to water chemistry limits. The licensee estimates
that the backwashes would increase by approximately 8 to 10 percent,
resulting in an additional 3 cubic meters of resin waste per year. The
resultant total generation rate of approximately 36 cubic meters per
year (CMY), is about half the current industry median value of 85 CMY
and well below the FES assumed value of 697 CMY. The EPU would not
involve changes in either reactor water cleanup flow rates or filter
performance. The staff concludes that implementation of the proposed
EPU would not have a significant impact on the volume or activity of
wet radioactive solid waste at DAEC.
Dry Waste: Dry waste consists of air filters, miscellaneous paper
and rags from contaminated areas, contaminated clothing, tools and
equipment parts that cannot be effectively decontaminated, and solid
laboratory wastes. The activity of much of this waste is low enough to
permit manual handling. Dry waste is collected in containers located
throughout the plant, compacted as practicable, and then sealed and
removed to a controlled-access enclosed area for temporary storage.
Because of its low activity, dry waste can be stored until enough is
accumulated to permit economical transportation to an offsite
processing facility or a burial ground for final disposal. DAEC has
indicated that there will be no significant change in the amounts,
level of controls, or methodology used for the processing dry
radioactive waste at DAEC. The staff concludes that implementation of
the proposed EPU should not have a significant impact on the volume or
activity of the dry solid radioactive waste at DAEC.
Irradiated Reactor Components: Irradiated reactor components, such
as spent control blades, in-core ion chambers, and fuel assemblies,
must be disposed of after the life of the component. The volume and
activity of waste generated from spent control blades and in-core ion
chambers might increase slightly under the higher flux conditions
associated with power uprate conditions. This increase would be
mitigated by improved longer-lived local power range monitor strings,
improved lower-cobalt-content control rod blades, and longer fuel
cycles. Additionally, reactor equipment waste is stored in the spent
fuel storage pool before removal to in-plant or offsite storage and
final disposal in shielded containers or casks. Because of the
mitigating effects of extended burnup and increased U-235 enrichment
compared to the burnups and enrichment evaluated in the original FES,
implementing the EPU would not be likely to have a significant impact
on the amount of irradiated reactor components discharged from the
reactor.
DAEC plans to load 152 fresh fuel bundles in the initial refueling
to commence operation under the EPU. This is approximately 30 bundles
more than for the current refueling cycle. Because of the mitigating
effects of extended burnup and increased U-235 enrichment on fuel
throughput under power uprate operating conditions, the number of
irradiated fuel assemblies discharged from the reactor would not
increase during subsequent reloads. Additionally, the 24-month
operating cycle would result in one less fuel reload before the license
expiration. These wastes are currently stored in the spent fuel pool
and are not shipped off site. The staff concludes that implementation
of the proposed EPU should not have a significant impact on the volume
or activity of the irradiated reactor components at DAEC.
The staff has generically evaluated the annual environmental impact
of low- and high-level solid wastes for a 1000 MWe reference reactor.
The estimated activity of these wastes is given in Table S-3 in 10 CFR
51.51 and would be bounding under the proposed EPU conditions.
Dose Impacts
The staff evaluated in-plant and offsite radiation as part of its
review of environmental impacts of the proposed EPU.
In-Plant Radiation
Increasing the rated power at DAEC might increase the radiation
levels in the reactor coolant system; however, these potential
increases would be compensated for by physical plant improvements and
administrative controls, such as shielding, feedwater chemistry, and
the plant radiation
[[Page 55708]]
protection program. Over the past 7 years, DAEC has decreased the
occupational dose to DAEC workers by 15 percent per year (based on a
rolling 3-year average). The licensee stated that it expects to
continue its downward trend while operating under the proposed EPU
conditions. The staff evaluated shielding, dose reduction programs, and
corrosion as part of its evaluation.
Shielding: DAEC was conservatively designed with respect to
shielding and radiation sources. In the shielding analysis, the assumed
concentrations for reactor water fission and corrosion products were 4
microcuries per cubic centimeter and 0.06 microcuries per cubic
centimeter, respectively. The normal value of both reactor water
fission and corrosion products is 0.01 microcuries per cubic
centimeters. With expected increases in operating activity proportional
to the proposed power increase, the design shielding assumptions remain
bounding at EPU conditions.
Feedwater Chemistry: The original design was based on an assumed
value for nitrogen-16 (N-16) concentration of 100 microcuries per gram.
To support the injection of hydrogen into the feedwater, the licensee
conducted a special test in 1989 to evaluate the impact and efficacy of
injection rates of up to 45 standard cubic feet per minute (scfm). The
licensee stated that the results of this test led to an injection rate
of 6 scfm, which yields an acceptable recirculating system
electrochemical potential and no discernable N-16 dose rate increase.
Between October 1994 and October 1996, the hydrogen injection rate was
increased to 15 scfm to extend corrosion protection to portions of the
core internals, with a resultant increase in dose rates of 3.3 times
the rates without hydrogen injection. Although occupancy in some areas
was restricted, no shielding modifications were required to maintain
radiation levels within acceptable levels. Since 1996, DAEC has
undertaken a noble metals injection program to protect the core
internals from corrosion by reducing hydrogen use. As a result, the
current operational hydrogen injection rate is 6.0 scfm. The 20-percent
increase in the N-16 dose rate from EPU would not affect the
acceptability of the shielding design.
The equilibrium activity concentration of corrosion products that
have plated out on reactor coolant piping and other surfaces may
theoretically increase by the square of the power uprate increase. This
is primarily due to the linear increase in corrosion products in the
primary system from the feedwater flow increase and the linear increase
in activation events from the core average flux increase. However, this
potential increase would be mitigated by four dose reduction programs
at DAEC:
1. Oxygen injection in the condensate system started in 1987.
2. Recirculating system chemical decontaminations in 1990, 1992,
1993, and 1995.
3. Stellite reduction efforts started in 1993.
4. Depleted zinc addition started in 1994.
As a result of these efforts, the concentration of soluble cobalt-
60 in the reactor water has decreased from 1.3E-04 microcuries per
milliliter in early 1987 to 2.7 E-05 microcuries per milliliter in
2000. The potential increases in the volume and activity of activated
corrosion products at EPU operating conditions would not negate these
efforts, and it is expected that concentrations would continue to
decline under EPU conditions. Consequently, operating and shutdown
radiation levels would not increase under EPU conditions.
Plant Radiation Protection Program: The plant radiation protection
program would be used to maintain individual doses consistent with as-
low-as-reasonably-achievable policies and below the established limits
of 10 CFR Part 20. Routine plant radiation surveys required by the
radiation protection program would identify increased radiation levels
in accessible areas of the plant, and radiation zone postings and job
planning would be adjusted, if necessary. Time within radiation areas
is controlled under the radiation protection program. Administrative
dose control limits are established well below regulatory criteria and
provide a significant margin to regulatory dose limits. The licensee
stated that administrative dose limits were not routinely exceeded
under present power conditions.
On the basis of the above information, the staff concludes that the
expected annual collective dose for DAEC, following the proposed EPU,
would still be bounded by the dose estimates in the FES.
Offsite Doses
The slight increase in normal operational gaseous activity levels
under the EPU would not affect the large margin to the offsite dose
limits established by 10 CFR Part 20. In addition, doses from liquid
effluents, currently zero, would remain zero under EPU conditions.
The DAEC Technical Specifications implement the guidelines of 10
CFR Part 50, Appendix I, which are within the 10 CFR Part 20 limits.
Adjusting current values for projected EPU increases, the offsite dose
at EPU conditions is estimated to be 2.6 E-03 millirads for noble gas
gamma air, 1.6E-02 millirads for noble gas beta air, and 6.8E-03
thyroid millirem for particulates and iodine. The Appendix I limits are
10 millirads, 20 millirads, and 15 thyroid millirem, respectively. The
offsite dose would continue to be within the Technical Specification
dose limits.
The EPU would not involve significant increases in an offsite dose
from noble gases, airborne particulates, iodine, or tritium.
Radioactive liquid effluents are not routinely discharged from DAEC. In
addition, as stated by the Radiological Environmental Monitoring
Program for DAEC, radiation from shine is not now a significant
exposure pathway, and it would not be significantly affected by the
proposed EPU.
The EPU would not create any new or different sources of offsite
dose from DAEC operation, and the EPU would not involve significant
increases in present radiation levels. Therefore, under EPU conditions,
offsite dose would remain well within regulatory criteria and would not
have a significant impact. The staff concludes that the estimated doses
from both the liquid and gaseous release pathways resulting from EPU
conditions are within the design objectives specified by 10 CFR part
50, appendix I, and the limits of 10 CFR part 20.
Accident Analysis Impacts
The staff reviewed the licensee's analyses and performed
confirmatory calculations to verify the acceptability of the licensee's
calculated doses under accident conditions. The staff concludes that
the proposed EPU would not significantly increase the probability or
consequences of accidents and would not result in a significant
increase in the radiological environmental impact of DAEC under
accident conditions. If the license amendment request is approved, the
result of the staff's calculations will be presented in the safety
evaluation issued with the license amendment.
Fuel Cycle and Transportation Impacts
The EPU would involve an increase in the average enrichment of the
fuel bundle. The environmental impacts of the fuel cycle and of
transportation of fuel and wastes are described in Table S-3 and S-4 of
10 CFR 51.51 and 10 CFR 51.52, respectively. Table S-3 of 10 CR 51.51
and S-4 of 10 CFR 51.52 were
[[Page 55709]]
adopted by the licensee after DAEC received its operating license.
Consequently, the DAEC FES does not contain a uranium fuel cycle
environmental analysis similar to Table S-3. The impacts of
transportation are addressed in the Environmental Report and the FES,
although the conclusions are not presented in the format of Table S-4.
An NRC assessment (53 FR 30355, dated August 11, 1988, as corrected by
53 FR 32322, dated August 24, 1988) evaluated the applicability of
Table S-3 and S-4 to higher burnup cycles and concluded that there is
no significant change in environmental impacts for fuel cycles with
uranium enrichments up to 5 weight-percent U-235 and burnups less than
60 gigawatt-day per metric ton of uranium (GWd/MTU) from the parameters
evaluated in Tables S-3 and S-4. Because the fuel enrichment for the
EPU would not exceed 5 weight-percent U-235 and the rod average
discharge exposure would not exceed 60 GWd/MTU, the environmental
impacts of the proposed EPU would remain bounded by these conclusions
and would not be significant.
Summary
The proposed EPU would not significantly increase the probability
or consequences of an accident, would not introduce any new
radiological release pathways, would not result in a significant
increase in occupational or public radiation exposures, and would not
result in significant additional fuel cycle environmental impacts.
Accordingly, the NRC concludes that no significant radiological
environmental impacts are associated with the proposed action. Table 2
summarizes the radiological environmental impacts of the proposed EPU.
Table 2.--Summary of Radiological Environmental Impacts of EPU at DAEC
------------------------------------------------------------------------
------------------------------------------------------------------------
Radiological Waste Stream Impacts:
Gaseous Waste................. An increase in release rate that is
linearly proportional to the power
increase would be expected.
Liquid Waste.................. No change in DAEC zero liquid
release policy.
Solid Waste:
Wet Waste................. Backwashes would increase to create
approximately 3 cubic meters of
resin per year.
Dry Waste................. No significant changes.
Irradiated Components..... No significant changes.
Dose Impacts...................... May potentially increase radiation
levels; dose would remain within
permitted levels in-plant and
offsite.
Accident Analysis Impacts......... No significant increase in the
probability or consequences of an
accident.
Fuel Cycle and Transportation..... Increase in bundle average
enrichment; impacts would remain
within the conclusions of Table S-3
and Table S-4 of 10 CFR Part 51.
------------------------------------------------------------------------
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.
As stated previously, the estimated cost of adding this nuclear
generating capacity is approximately half the cost projected for
purchasing the power and one-third the cost of producing the power by
constructing a new combined-cycle, natural-gas-fueled facility. Alliant
concluded that increasing DAEC's capacity would be the most economical
option for increasing power supply. Furthermore, unlike fossil fuel
plants, DAEC does not routinely emit sulfur dioxide, nitrogen oxides,
carbon dioxide, or other atmospheric pollutants that contribute to
greenhouse gases or acid rain.
Alternative Use of Resources
This action does not involve the use of any resources different
than those previously considered in the FES for DAEC, dated March 1973.
Agencies and Persons Consulted
In accordance with its stated policy, on August 23, 2001, the NRC
staff consulted with the Iowa State official, Mr. D. McGhee of the
Department of Public Health, regarding the environmental impact of the
proposed action. The State official had no comment.
Finding of No Significant Impact
On the basis of the environmental assessment, the NRC concludes
that the proposed action 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 application dated November 16, 2000, as supplemented April
16 (two letters) and 17; May 8 (two letters), 10, 11 (two letters), 22,
and 29; June 5, 11, 18, 21, and 28; July 11, 19, and 25; and August 1,
10, 16, and 21; and October 17, 2001, and NMC's ``Supplement to DAEC
Environmental Report,'' submitted on September 22, 2000. Documents may
be examined and/or copied for a fee at the NRC's Public Document Room,
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 on the NRC Web
site, http://www.nrc.gov (the Electronic Reading Room). If you do not
have access to ADAMS or if there are problems in accessing the
documents located in ADAMS, contact the NRC Public Document Room
Reference staff at 1-800-397-4209, or 301-415-2737, or by e-mail at
[email protected].
Dated at Rockville, Maryland, this 31st day of October 2001.
For the Nuclear Regulatory Commission.
William D. Reckley,
Acting Chief, Section 1, Project Directorate III, Division of Licensing
Project Management, Office of Nuclear Reactor Regulation.
[FR Doc. 01-27716 Filed 11-1-01; 8:45 am]
BILLING CODE 7950-01-P