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Box 19276,
62794-9276 - ( 217) 782-3397
60601 - (312) 814-6026
(217) 782-5544
TDD: (217) 782-9143
July 20, 2006
Dorothy Gunn, Clerk
Pollution Control Board
100 West Randolph Street
Suite 11-500
Chicago, IL 60601
RE :
IEPA - 07-01
(Provisional Variance-Water)
Dear Ms. Gunn :
Pursuant to Subsection 37(b) of the Environmental Protection Act (415 ILCS 5/37(b)), attached is
a copy of the Illinois EPA's recent approval of a request for provisional variance. As you know,
the Board must maintain for public inspection copies of all provisional variances filed with it by
the Illinois EPA. Please feel free to call me at the number referenced above should you have any
questions .
nnie L. Tonsor
Associate Counsel
Division of Legal Counsel
ROCKFORD-4302 North Main Street, Rockford, IL 61103-(815) 987-7760
PLAINES - 9511 W . Harrison St., Des Plaines, IL 60016-(847) 294-4000
ELGIN--595 South State, Elgin, IL 60123-(847) 608-3131
PEORIA-5415 N. University St., Peoria, IL 61614 -(309) 693-5463
LAND-PEORIA-7620 N . University St., Peoria, IL 61614-(309) 693-5462
CHAMPAIGN- 2125 South First Street, Champaign, IL 61820-(217) 278-5800
SPRwcHELD-4500 S. Sixth Street Rd ., Springfield, IF 62706-(217) 786-6892
COHINSVILLE-2009 Mall Street, Collinsville, IL 62234-(618) 346-5120
MARION-2309 W. Main St., Suite 116, Marion, IL 62959-(618) 991-7200
JUL 2 5 2006
Pollution Control Board
IEPA 07-003

July 19, 2006
Exelon Generation Company, L .L.C .
Quad Cities Nuclear Power Station
v .
IEPA - 07-01
(Provisional Variance-Water)
Respondent .
Re :
Provisional Variance From Special Condition 6B
of NPDES Permit IL0005037
Dear Mr. Gideon :
The Agency has completed its technical review of the attached provisional variance
request (Exhibit A) dated July 17, 2006, and submitted by Exelon Generation Company,
L.L.C. Quad Cities Nuclear Power Station (Exelon's Quad Cities Station)
Based on the review, the Agency GRANTS the requested variance subject to specific
conditions set forth below for a period of 45 days or until the additional 100 excursion
hours are utilized, whichever occurs first .
Exelon's Quad Cities Station is seeking a provisional variance from Special Condition 6B
of its NPDES permit beginning the day its current 87.6 excursions hours are utilized to
continue operation of its generating station
Exelon's Quad Cities Station is a nuclear fueled steam electric generating facility located
on the Mississippi River at River Mile 506.8 near Cordova, Illinois . It operates its
cooling water system in open cycle mode. Cooling water is taken from the Mississippi
River, passes through the plant system and is then discharged by diffusers into the
Mississippi River . Maximum design flow of this system is 2,253 cfs
Exelon's Quad Cities Station seeks a variance from Special Condition 6B of NPDES
Permit IL0005037 . This condition establishes the thermal discharge ranges for Exelon's
IEPA 07-003

Quad Cities Station .
Additionally, it allows Exelon's Quad Cities Station excursion
hours from these limits . Excursion hours are periods of time in which the temperature at
the edge of the mixing zone may be 3°F warmer than the temperature limit in the permit
Exelon's Quad Cities Station may utilize only 1% (87 .6) of the hours in a 12-month
period ending with any month as excursion hours
The Special Condition 6B also requires that water temperature in the Mississippi River at
the edge of the mixing zone shall at no time exceed by 3°F the maximum limits of 86°F
in July and August and 85°F in September . Normally, Exelon's Quad Cities Station can
operate within these limits because the ambient temperature in the Mississippi River at
the intake points (or above the plant) remains below the non-excursion hour temperature
Ordinarily, the Mississippi River has significant river flows
These significant river
flows enable Exelon's Quad Cities Station to meet its permit conditions even when
ambient temperatures approach non-excursion hour temperature limit
At this time,
however, the Mississippi River is at extremely low flow condition . The river flow is
currently at 21,000 cfs compared to a normal river flow of 68,000 cfs. This low flow
condition, coupled with high ambient river temperatures, are the bases for the need for
additional excursion hours
Inlet river temperatures have been ranging around 83°F to 86°F . Based on long range
weather forecasts and continued low river flow conditions, Petitioner predicts it will
consume a large percentage of its permitted excursion hours before the end of this
summer, even though a cold front is predicted to reduce the current extreme heat
condition. Petitioner claims the only alternative available for the station, other than relief
pursuant to this provisional variance request, is to shut down the station. Derating the
facility will not resolve this situation due to the high ambient temperatures . In addition,
power demand is extremely high because of the current weather conditions
The Agency has reviewed the requested provisional variance and has concluded the
following :
1. The environmental impact from the requested relief will be closely monitored and
the Agency will be immediately notified of any significant impact along with
actions taken to remedy the problem
2. No other reasonable alternatives appear available
3. No public water supplies will be affected
4. No federal regulations will preclude the granting of this request ; and
5. Exelon Quad Cities Station will face an arbitrary and unreasonable hardship if the
request is not granted
IEPA 07-003

The Agency hereby GRANTS the Exelon Quad Cities Station a provisional variance
from Special Condition 6B of NPDES Permit IL0005037 as follows
(1) Exelon's Quad Cities Station is granted 100 provisional variance excursion
hours ;
(2) The provisional variance will begin (1) on the date that Exelon's Quad Cities
Station either exhausts the 87 .6 permitted excursion hours or (2) on the date that
Exelon Quad Cities Station first exceeds the current permitted excursion hour
temperature limits (July 89°F, August 89°F, and September 88°F)
provisional variance will end on the date that the 100 provisional variance
excursion hours are used, but in no case later than 45 days following the start of
the provisional variance period
(3) Exelon's Quad Cities Station, during the 100 provisional variance excursion
hours, may exceed the maximum temperature limit stated in Special Condition 6B
in NPDES permit IL0005037 by no more than 5° (July 91°F, August 91°F, and
September 90°F) .
This provisional variance is subject to the following conditions
A. During the variance period Exelon Quad Cities Station shall continuously
monitor intake, discharge and receiving water temperatures and to visually
inspect intake and discharge areas at least three times daily to assess any
mortalities to fish and other aquatic life ;
B. Exelon Quad Cities Station shall document environmental conditions
during the term of the provisional variance, including the activities
described in A above of this Section, and submit the documentation to the
Agency and the Department of Natural Resources within 30 days after the
provisional variance expires ;
C. Exelon's Quad Cities Station shall continue ongoing biological studies to
characterize how fish and mussels respond to thermal conditions present in
the affected portion of the Mississippi River. These studies include those
mentioned on page five of Exelon's July 17, 2006 Emergency Application
for Provisional Variance. These same studies were described in a July 11,
2006 e-mail message (Exhibit B) from Exelon to Mr . Rob Thompson of
USEPA Region 5 relating the efforts by Exelon to study aspects of river
biology suggested at recent meetings concerning long-term relief from
existing water quality standards at this site
In addition, Exelon must
conduct a mussel study specific to this provisional variance; to document
this activity; and to submit the documentation for the mussel study to the
Agency and the Department of Natural Resources within 60 days after
IEPA 07-003

completing the survey described herein
Specifically, Exelon's Quad
Cities Station must prepare a study plan within three days of the beginning
date of this provisional variance to address the issue of increased
excursion hours (increase in thermal stress) on unionid mussels in the
Mississippi River in the vicinity of the discharge . The plan must include a
survey of the mussel beds identified in a recent report: Draft Report
Unionid Mussel Biothermal Assessment for the Quad Cities Nuclear
Station, Mississippi River Miles 503 .0 to 506.9 (Exhibit C). The survey
must address the apparent health of the mussels within the mussel beds
given the higher than allowed river temperatures and longer duration of
temperature excursions. Survey dives to ascertain effects on the mussel
beds must begin as soon as possible after either the increase of excursion
hours or maximum temperature relief afforded by the provisional variance
are utilized. Conditions pertinent to the mussel populations to be recorded
during the surveys will be much the same as conducted for the baseline
study referenced above. These must include but are not limited to mussel
species occurrence and density, age, zebra mussel infestation and apparent
i.e ., any outward signs of heat stress such as morbidity, reflex
time, position in the substrate, etc. Plant discharge temperatures, upstream
river temperatures, incidence of excursion hours and other pertinent
information must be provided to build an understanding of the conditions
to which the mussels have recently been exposed . Surveys must continue
until excursion hours are no longer being utilized, or in other words, until
the weather conditions causing the need for more excursion hours have
moderated. The final report for this study must address the changes noted
in mussel populations from the previous study . Verbal reports are due to
the Agency at regular intervals during the surveys . These reports must
include any information on mussel die-off. If mussel die-off downstream
from the discharge is found and is attributable to the thermal affects of the
effluent, as compared to the condition of upstream populations, a
monetary settlement will be required as calculated by the formula the
Illinois Department of Natural Resources uses for mussel die-off
settlements ;
D. Exelon Quad Cities Station shall immediately notify the Agency and the
Department of Natural Resources of any unusual conditions, including
mortalities to fish or other aquatic life; shall immediately take action to
remedy the problem; shall investigate and document the cause and
seriousness of the unusual conditions while providing updates to the
Agency and the Department of Natural Resources as changes occur until
normal conditions return; shall notify the Agency and the Department of
Natural Resources when normal conditions return ; and shall submit the
documentation to the Agency and the Department of Natural Resources
within 30 days after normal conditions return ;
IEPA 07-003

E .
Exelon Quad Cities Station shall develop and implement a response and
recovery plan to address any adverse environmental impact due to thermal
conditions resulting from the provisional variance, including loss and
damage to aquatic life ;
F. Quad Cities Station shall notify Roger Callaway of the Agency by
telephone at 217/782-9720 when the need for the 100 additional excursion
hours begin and again if the excursion hours are totally utilized . Written
confirmation of each notice shall be sent within five days to the following
IEPA 07-003

Robert A. Messina
Chief Legal Counsel
Illinois Environmental Protection Agency
Bureau of Water - Water Pollution Control
Attention: Roger Callaway
1021 North Grand Avenue East, MC #19
Springfield, Illinois 62794-9276
G. Exelon Quad Cities Station shall sign a certificate of acceptance of this
provisional variance and forward that certificate to Roger Callaway at the
address indicated above within one day of the date of this order
certification should take the following form
I(We) , hereby accept and agree to be bound by all
terms and conditions of the provisional variance granted by the
Agency in dated
Authorized Agent
Exelon Quad Cities Station shall continue to monitor and maintain compliance with all
other parameters and conditions specified in its NPDES Permit No. IL0005037 .
The Illinois EPA grants this provisional variance in accordance with its authority
contained in Sections 35(b), 36
(c), and 37(b) of the Illinois Environmental Protection
Act (415 ILCS 5/35(b), 36(c), and 37(b) (2004) . The decision to grant this provisional
variance is not intended to address compliance with any other applicable laws or
IEPA 07-003

Due to the volume of this pleading,
please contact the Clerk's Office
to view this file
IEPA 07-003

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