SVP-07-051, Provisional Variance from National Pollutant Discharge Elimination System (NPDES) Permit No. IL0005037

Provisional Variance from National Pollutant Discharge Elimination System (NPDES) Permit No. IL0005037

ML072390020
Person / Time
Site:	Quad Cities
Issue date:	08/17/2007
From:	Tulon T Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SVP-07-051
Download: ML072390020 (17)

Text

Exekrn.

Exelon Generation Company, LLC Quad Cities Nuclear Power Station www.exeloncorp.com Nuclear 22710 206h Avenue North Cordova, IL61242-9740 SVP-07-051 August 17, 2007 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265

Subject:

Provisional Variance from National Pollutant Discharge Elimination System (NPDES) Permit No. IL0005037 In accordance with Technical Specifications, Appendix B, Section 2.2, "Reporting Related to the NPDES Permits and State Certifications," enclosed is the provisional variance requested by Quad Cities Nuclear Power Station from NPDES Permit IL0005037 and the associated Illinois Environmental Protection Agency approval.

Should you have any questions concerning this letter, please contact Mr. W. J. Beck at (309) 227-2800.

Respectfully, Ti~thy J. Tulon

§Ke Vice President 0uad Cities Nuclear Power Station Attachments: A - Provisional Variance Request from NPDES Permit No. IL0005037 B - Approval of Provisional Variance from NPDES Permit No. IL0005037 cc: Regional Administrator - NRC Region III NRC Senior Resident Inspector-- Quad Cities Nuclear Power Station Cýz (

Attachment A Provisional Variance Request from NPDES Permit No. IL0005037

Exelon.

Exelon Generation Company, LLC Quad Cities Nuclear Power Station www.exeloncorp.com Nuclear 22710 206" Avenue North Cordova. IL61242-9740 PM-07-012 August 8, 2007 Mr. Mike Garretson Manager, Compliance Assurance Section Division of Water Pollution Control Illinois Environmental Protection Agency 1021 North Grand Avenue East Springfield, Illinois 62794

Subject:

Quad Cities Nuclear Power Station NPDES Permit No. IL0005037 Provisional Variance Request - Emergency Application

Dear Mr. Garretson:

Exelon Generation Company, L.L.C. ("Exelon") hereby requests that the Illinois Environmental Protection Agency ("IEPA" or "Agency") grant a provisional variance for Quad Cities Nuclear Power Station ("Quad Cities," "Station" or "Facility"), pursuant to Section 35(b) of the Environmental Protection Act ("Act") 415 ILCS 5/35. Exelon submits this Emergency Application for a provisional variance consistent with IEPA procedures at 35 III. Adm. Code 180.204. Quad Cities is located on the Mississippi River in Rock Island County. The Station discharges wastewater pursuant to NPDES Permit No. 1L0005037, which IEPA issued on December 17, 2001. The Station submitted its NPDES Permit renewal application to the Agency on November 18, 2004.

Station Description Quad Cities Station is a nuclear-fueled steam electric generating facility located near Cordova, Illinois, on the Mississippi River at River Mile 506.8. The two boiling water reactors have a combined maximum generating capacity of 1824 megawatts electric.

Circulating water used to cool and condense the steam from the generating process is withdrawn from and discharged to the Mississippi River.

Quad Cities operates a condenser cooling water system in open cycle mode. In this mode, cooling water is drawn from the Mississippi River into an intake canal, passes through the plant systems, and is discharged via diffusers into the Mississippi River (Outfalls 001 and 002). The maximum design flow is 2253 cfs or 1,011,000 gpm. Open cycle operation with the diffusers was initially permitted by the IEPA on December 22, 1983.

Illinois Environmental Protection Agency August 8, 2007 Page 2 of 7 Relief Requested A provisional variance is being requested from the restriction in Special Condition 6B of Quad Cities Station's NPDES Permit that limits the number of hours during which the Station discharge may exceed 86 OF in August and 85 OF in September to 87.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> (one percent of the hours in a 12 month period). Special Condition 6B also provides that the Station shall not cause water temperatures in the Mississippi River (beyond the mixing zone) to exceed by more than 3 OF the maximum limit of 86 OF in August and 85 OF September, respectively.

In light of existing low Mississippi River flows caused by lack of rain in the upper Mississippi River watershed, high intake water temperatures, high amb'fbnt air temperatures, and power demands, Exelon requests a two-part order of stepwise implementation provisional variance for Quad Cities Station:

" Part 1 requests that a provisional variance be issued to Quad Cities Station granting an additional 200 excursion hours for a period designated to begin on the date that the permitted 87.6 excursion hours are exhausted which is projected to be Saturday, August 11, 2007 based on the extended forecast combined with the current Mississippi River flow projections.

" Part 2 requests that a provisional variance be issued that allows Quad Cities Station to exceed the maximum temperature limit stated in Special Condition 6B by no more than 5 OF (August 91 OF and September 90 OF).

Quad Cities will notify the Agency when Parts I and 2 of this particular provisional variance are triggered. The provisional variance period will end on the date that the additional 200 excursion hours are used, but in no case later than 45 days following the start of the provisional variance period.

Necessity for Request Special Condition 6B of NPDES Permit limits the temperature at the edge of the mixing zone to 86 0F August, except when the Station is using excursion hours, during which time the temperatures at the edge of the mixing zone may be 30F warmer than this limit.

Historically, Quad Cities Station has been able to meet the edge of the mixing zone limit of 86 OF during August due to the fact that the ambient temperatures of the Mississippi River (measured upstream of the discharge) generally remain below the non-excursion hour limit during this time of year. Even when the ambient river temperatures begin to approach the non-excursion hour limits, the significant river flows, which are generally characteristic of the Mississippi River, are sufficient to allow the Station to avoid using a significant percentage of its excursion hour allowance. It is only during periods when the ambient river temperatures are very close to or exceed the non-excursion hour limits or during periods of extreme low river flows that the Station is forced to use its excursion hour allowance.

Illinois Environmental Protection Agency August 8, 2007 Page 3 of 7 During July and August 2006, extreme drought conditions existed and ambient temperatures in the Mississippi River exceeded Exelon's discharge limit of 86 OF reaching 88 OF. During this time period, the Station used 223 excursion hours (117 excursion hours in July and 106 excursion hours in August), authorized by emergency provisional variances issued by Illinois EPA.

This year, Illinois again faces unusually hot summertime condition. Quad Cities Station first began using excursion hours on Thursday, August 2, 2007 when it used 16.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and again on. Friday, August 3, 2007 when it used 17.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. Quad Cities Station predicts that its original NPDES permit allotment of 87.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> will be used up Saturday, August 11, 2007. The river flow is presently at 31,000 cfs compared to a normal river flow for this time of year of 42,000 cfs. The plant is expected to begin using excursion hours during the afternoon hours on Thursday, August 9, 2007 and remain on the excursion hour clock through the remainder of this week based on forecasted hot and humid weather conditions, absence of cooling during the evening hours and drastically low river flows. The river is not cooling off during the evening hours as is typical this time of year. Based on recent discussions with the Rock Island Corps of Engineers, river flow is predicted to hold between 20,000-30,000 cfs at Lock & Dam 14 with flow falling off to 14,000 cfs two weeks out. Exelon expressed concern to the Rock Island Corps of Engineers regarding the flow forecast. The Rock Island Corps of Engineers in turn has communicated Exelon's concerns to the St. Paul Corps of Engineers District hydrologist to hopefully avoid a repeat of last year's perturbation that suddenly dropped river flow to 12,600 cfs. Unfortunately, the projected falling river flows in 2007 are a repeat of what was experienced in 2006 and are a result of lack of precipitation in the upper Mississippi Valley.

Mississippi River flow is forecast to further decrease through the end of the month. With the current forecast of highs in the mid-90's for the next several days, river temperature is expected to increase another 3 to 40 F. At a river flow of 18,000 cfs, the calculated downstream temperature rise is 3.5 OF. Ifthe weather forecast holds true, inlet temperatures are expected to approach 86 OF, which when combined with a 3.5 OF delta T rise will place the Station over its maximum permitted August discharge temperature limit of 89 OF. The forecast for the upcoming week calls for a string of mid-90°F days with lows in the mid-seventies. Precipitation has been extremely low in many areas, most notably in the region of the headwaters of the Mississippi River in Minnesota.

Assessment of Environmental Impacts Under the auspices of IEPA, IDNR, Iowa DNR, USFWS and USEPA, Exelon has been conducting long-term thermal studies for Quad Cities Station. On April 19, 2007, Exelon Generation informed USEPA and IEPA of its plans to conduct additional fishery and mussel studies related to Quad Cities Station's thermal discharges. These additional studies are designed to supplement the extensive data and information previously obtained in order to more fully assess whether alternate thermal limits under 316(a) are

Illinois Environmental Protection Agency August 8, 2007 Page 4 of 7 appropriate and, if so, what those limits should be. Exelon plans to provide an interim status report to the Agency by January 15, 2008 which summarizes the additional fishery and mussel studies, status of ongoing discussions with the agencies, and additional research regarding long-term trends and possible alternative thermal compliance measures.

Most of the ongoing biological field work is planned for the warmer months in 2007 and 2008 and is designed to gather additional information regarding ecological conditions in the relevant portion of the river and to permit a more detailed assessment of the expected and existing biological community in the area. A significant portion of the biological work will focus on gaining more insight into the mussel community as well as fish species that may be important to mussel reploduction. Mussel bed substrate temperature probes (which were also utilized in 2006) were installed on May 22, 2007, and will remain in place through September (substrate temperature probe data will be downloaded on a monthly basis).

On June 7, 2007, we received a letter from U.S. Fish and Wildlife Service's (USFWS) providing comments on Exelon Generation's long term thermal study plans. USFWS provided important guidance regarding Habitat Conservation Planning and Incidental Take Permit Processing. We have accepted USFWS invitation to coordinate our work on those issues and expect to be meeting with the Agency in August to discuss details.

On June 20, 2007, Iowa Department of Natural Resources (DNR) responded to Exelon Generation's April 19, 2007 letter. Exelon and Iowa DNR are engaged in discussions regarding the process for pursuing relief under Section 316 (a).

The fishery studies (field work) detailed in our April 19, 2007 letter to USEPA began in mid-May and will continue on a biweekly basis. Dives to characterize additional mussel beds upstream and downstream of Quad Cities Station were performed June 21 through June 26. The goal of Exelon's long-term thermal relief proposal is to substantially mitigate the need for the emergency-type relief requested herein.

The biological studies already completed as part of Exelon's above-mentioned investigation of long-term, permanent relief options considered the effects on species of fish and shellfish that could result from increasing the number of excursion hours available to the plant. Preliminary results from the ongoing studies fully support the conclusion that granting the requested Provisional Variance will not cause significant or unacceptable adverse effects to these species.

This year's fish sampling of the mussel beds in the vicinity of Quad Cities Station began on May 16, 2007 and is currently being conducted. Three sample sessions have occurred to date. The numbers, density, and species of fish collected in the specific habitats are similar to those found within the general area of the mussel beds. Exelon also conducts fish surveys as part of its long-term monitoring program. These surveys

Illinois Environmental Protection Agency August 8, 2007 Page 5 of 7 are conducted twice a month from June through September. The species and abundance of fish observed are similar between the two sampling studies. Also during these sampling events, no unusual occurrences have been noted.

The recent ambient river temperature increase near Quad Cities has been gradual.

Species of fish that may possibly suffer from being exposed to temperatures in the excursion zone will already have taken refuge from the higher than normal ambient river temperatures. This movement is seen annually in connection with our long-term monitoring programs. Fish species that are observed to take refuge include walleye, sauger, northern pike, and a few redhorse species. As a result, such resident fish species will not be subject to any heat shock as a result of the requested additional excursion hours requested herein. Further, since Quad Cities Station is not proposing to increase cooling water intake, there will be no increase in impingement or entrainment as a result of the issuance of the requested Provisional Variance.

The recently conducted biological studies show that the mussel species in beds that are closest to the plant's discharge are generally more temperature tolerant, and are capable of surviving relatively short-term elevated thermal exposures. Species thought to be less thermally tolerant inhabit beds located further downstream, in the Cordova Bed, located about 1 mile downstream from the plant. However, because the considerable distance between the plant to the Cordova and the flow characteristics of the River (that cause much of the plant's thermal discharge to avoid the Cordova Bed) the Provisional Variance should not cause any appreciable harm to mussel species downstream of the plant. Mussel data shows that threatened and endangered species did not appear to be affected by the warm river temperatures in July and August 2006.

Alternatives to Requested Relief Quad Cities Station generally uses excursion hours during periods of extreme heat and low-river flows, as discussed above. Due in part to the mixing capacity provided by the Mississippi River, and the fact that ambient river temperatures rarely exceed the non-excursion hour NPDES Permit limits, only a relatively small percentage of the permitted excursion hours typically are used to cover any one of these periods. Additional hours are kept in reserve to deal with future periods of extreme weather or other contingencies. Based on river temperatures recorded so far this summer and projections for the balance of this month, it is likely that there will be days during which ambient river temperatures will approach or reach NPDES permit limits. Neither de-rating the units nor obtaining additional temporary cooling capacity will allow the Station to maintain compliance if the ambient river temperatures at the intake exceed the applicable discharge temperature limits. Under such conditions, the only option if the Station is to comply with its permit limits is for the Station to shut down. Without the power that Quad Cities Station could generate as a result of the requested provisional variance, there is a risk that the energy needs of Exelon's customers may not be met.

In addition, depending on the operating status of other generating stations in the area,

Illinois Environmental Protection Agency August 8, 2007 Page 6 of 7 Quad Cities Station continued operation may be essential for voltage support for the Commonwealth Edison Company and Mid American Transmission systems.

Mitigative Actions to be Taken During the Variance Period During the period when the Station operates under the requested provisional variance, Quad Cities Station will do the following: (1) continuously monitor the intake and discharge temperatures and assess water temperatures at the edge of the mixing zone using the NPDES Permit temperature monitoring curve; (2) on a daily basis, inspect the intake and discharge areas to assess any mortalities to aquatic life, and report the results of these monitoring activities to the Agency within 30 days of the expiration of the provisional variance (or such other time as agreed upon by the Agency); and (3) notify the Agency of any significant adverse environmental conditions observed that might be caused by operations authorized by the provisional variance, including mortalities to fish or other aquatic life, investigate the cause of such conditions, provide the Agency updates regarding the situation, including when normal conditions return, and submit a report to the Agency regarding these matters within 30 days of the expiration of the provisional variance period (or such other time as agreed upon by the Agency).

Summary Exelon requests that the Agency recommend the issuance of a two-part order of stepwise implementation provisional variance for Quad Cities Station to include: (1) an additional 200 excursion hours during which time the river temperature could exceed 86 OF in August and 85 OF in September. This part 1 of the provisional variance would become effective on the date that the permitted 87.6 excursion hours are exhausted through 45 days following the start of the provisional variance period and (2) approval to exceed that maximum temperature limit stated in Special Condition 6B in NPDES Permit IL 0005037 by no more than 5 OF (August 91 OF and September 90 OF). Quad Cities Station will notify the Agency when each part of the provisional variance is implemented and will keep the Agency updated on changing conditions. The provisional variance period will end on the date that the additional 200 excursion hours are used, but in. no case later than 45 days following the start of the provisional variance period.

Exelon believes that not granting this provisional variance to Quad Cities Station will impose an arbitrary and unreasonable hardship. A negative decision will almost certainly result in a loss of generating capacity in Northern Illinois during periods of great electrical demand and could impact voltage support for the Commonwealth Edison Company and Mid American Transmission systems, which includes Illinois and portions of Iowa. There are presently no provisional variance orders in effect for Quad Cities Station.

Illinois Environmental Protection Agency August 8, 2007 Page 7 of 7 If you should have any questions regarding these matters, please feel free to contact Vicki Neels at (309) 227-3200 or Mark StuhIman at (309) 227-2765 from Quad Cities, or John Petro, Senior Environmental Analyst, Exelon Generation at (630) 657-3209.

Very Truly Yours, William R. Gideon Plant Manager Quad Cities Station WRG/MS/jas

Attachment B Approval of Provisional Variance from NPDES Permit No. IL0005037

88/10/2007 14:20 217-557-1407 CAS PAGE U2/Ub ILLINOIS ENVIRONMENTAL PROTECTION AGENCY August 10, 2007 Exelon Generation Company, L.L.C. )

Quad Cities Nuclear Power Station )

)

)

Petitioner, )

)

v. ) IEPA 11

) "(Provisional Variance-Water)

ILLINOIS ENVIRONMENTAL PROTECTION AGENCY, )

Respondent. )

Re: Provisional Variance From Special Condition 6B of NPDBS Permit IL0005037

Dear Mr- Gideon:

The Illinois Environmental Agency (Agency) has completed its technical review of the attached provisional variance request (Exhibit A) submitted by Exelon Generation Company, L.L.C.

Quad Cities Nuclear Power Station (Exelon's Quad Cities Station) on August 8, 2007.

Based on the review, the Agency GRANTS the requested variance for a period of 45 days, subject to specific conditions set forth below.

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. The Agency permitted the open cycle operation with diffusers on December 22, 1983.

Exelon's Quad Cities'Station seeks a variance from Special Condition 6B of NPDES Permit 11,0005037 (Attachment B). This condition establishes thermal discharge limits for Exelon's Quad Cities Station. Additionally, 6B 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 30F warmer than the temperature limhit in the permit. Exelon's Quad Cities Station may only use 1% (87.6) of the hours in a 12-month period ending with any month as excursion hours.

8/110/2007 14:20 217-557-1407 CAS PAGE 03/06 Special Condition 6B3 also requires that water temperature in the Mississippi River at the edge of the mixing zone shall at no time exceed by 3F the maximum limits of 86T in July and August and 85T 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 limit.

Under normal conditions, the Mississippi River has significant river flows. These 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 low flow conditions during a period of time of extreme summer heat. The river flow is currently at 31,000 cfs compared to a normal river flow of 42,000 cfs during this time of year.

This low flow condition, coupled with high ambient river and air temperatures and the need to maintain power on the grid during this extreme weather condition period, have necessitated Exelon's Quad Cities Station's request for a provisional variance.

Due to the extremely hot conditions, Exelon's Quad Cities Station began using excursion hours on Thursday, August 2, 2007; it used 16.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> on that date. On Friday, August 3, 2007, Exelon's Quad Cities Station used an additional 17.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. Exelon's Quad Cities Station expects to begin using excursion hours agami during the afternoon of Thursday, August 9, 2007, and to continue to need them for the remainder of the week, given current forecasts and river flows. Exelon's Quad Cities predicts that it will use the rest of the permitted excursion hours on Saturday, August 11, 2007.

Besides needing additional excursion hours, high temperatures and low river flows have adversely affected the ability of Exelon's Quad Cities Station to meet its thermal discharge limits contain in Special Condition 6-B. River flows are currently at 31,000 cfs, compared to the normal of 42,000 during this time of year. Discussions between Exelon's Quad Cities Station and the Rock Island Corps of Engineers indicate that river flow is predicted to hold in the 20,000 to 30,000 cfs range at Lock and Darn 14, with flows falling off to 14,000 cfs in about two weeks.

If future forecasts are correct, the river flow will decrease even further. With mid-90's temperatures predicted over the next several days, river temperatures are expected to increase 3 to 4 degrees F. Based on a river flow of 18,000 cfs, the calculated downstream temperature rise is 3.5 degrees F. As a result, the inlet temperatures to the Exelon Quad Cities Station will approach 86 degrees F. Combined with the 3.5 degree rise by the facility, Exelon Quad Cities Station will exceed the August permitted discharge limit of 89 degrees F.

The Agency has reviewed the provisional variance request and has concluded the following:

1. Exelon's Quad Cities Station will closely monitor the environmental impact from the requested relief and will immediately notify the Agency 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;

08/10/2807 14:20 217-557-1407 CAS PAGE 04/06

4. No federal regulations will preclude the granting of this request; and

5. Exelon Quad Cities Station will face an arbitrary and unreasonable hardship ifthe request is not granted.

The Agency hereby GRANTS Exelon's Quad Cities Station a provisional variance from Special Condition 6B of NPDES Permit IL0005037, subject to the following conditions:

1. Exelon's Quad Cities Station is granted 200 provisional variance excursion hours.

2. The provisional variance will begin on the date that Exelon's Quad Cities Station either (1) exhausts the 87.6 permitted excursion hour, or (2) on the date that Exelon's Quad Cities Station first exceeds the current permitted excursion hour temperature limits in Special Condition 6B (August 89 degrees and September 90 degrees). The provisional variance will end on the date that the 200 provisional variance excursion hours are used, but in no case later that 45 days following the start of the provisional variance period.

3. Exelon's Quad Cities Station, during the 200 provisional variance excursion hours, may exceed the maximum temperature limits stated in Special Condition 6B by no more than 5 degrees (August 91 degrees and September 90 degrees)

4. During the variance period, Exelon Quad Cities Station must 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;

5. Exelon Quad Cities Station shall document environmental conditions during the term of the provisional variance, including the activities described in 4. 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;

6. 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 4 of Exelon's Quad Cities Station's August 8, 2007 Emergency Application for Provisional Variance. In addition, Exelon's Quad Cities Station must continue to 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 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 Biothennal Assessment for the Quad Cities Nuclear Station, Mississippi River Miles 503.0 to 506.9 (attached). The survey must address the apparent health of the mussels within the mussel beds given the higher than

08/110/2007 14:20 217-557-1407 CAS PAGE 05/06 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 inlude, but are not limited, to mussel species' occurrence and density, age, zebra mussel infestation and apparent condition, 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 used, 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;

7. 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; immediately take action to remedy the'problem; 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; notify the Agency and the Department of Natural Resources when normal conditions return; and submit the documentation to the Agency and the Department of Natural Resources within 30 days after normal conditions return;

8. 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;

9. By January 15, 2008, Exelon Quad Cities Station shall provide an interim report to the Agency that summarizes all additional fishery and mussel studies, and provides the status of all ongoing discussions with other agencies regarding thermal issues, and the status of research regarding long-term trends and possible alternative thermal compliance measures that will be implemented should Exelon's Quad Cities Station's request for alternate thermal limits under 316 (a) not be granted.

10. Exelon's Quad Cities Station shall notify Roger Callaway of the Agency by telephone at 217/782-9720 when the need for the 200 additional excursion hours begin and again if the excursion hours are totally used. Written confimnation of each notice shall be sent within five days to the following address:

08/10/2007 14:20 217-557-1407 CAS HA,,6.. Ub/10b Illinois Environmental Protection Agency Bureau of Water - Water Pollution Control Attention: Roger Callaway 1021 North Grand Avenue East, MC #19 Springfield, Illinois 62794-9276

11. 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. The 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 Petitioner Authorized Agent Title Date 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 regulations.

Sinfe ely, 1 RkobertA.U essina Chief Legal Counsel

ExelQf.

Exelon Generation www.exeloncorp.com Nuclear Quad Cities Generating Station 22710 206th Avenue North Cordova, IL61242-9740 Tel 309-654-2241 SVP-07-050 August 10, 2007 Mr. Roger Callaway Compliance Assurance Section Division of Water Pollution Control Illinois Environmental Protection Agency 1021 North Grand Avenue East Springfield, Illinois 62794 Re: Quad Cities Nuclear Power Station NPDES Permit No. IL0005037 Provisional Variance Request - Emergency Application - IEPA 08-11

Dear Mr. Callaway:

Thank you for the time, consideration and attention IEPA dedicated to Exelon's Provisional Variance Request. We sincerely appreciate all of your efforts. Below is Quad Cities Station's Certificate of Acceptance of the Provisional Variance Order issued by IEPA in this matter.

Very Truly Yours, Ti thy J.STulon Sifte Vice President Quad Cities Station TJT/MS/tsr

SVP- 07-050 IL EPA Page 2 of 2 Certificate of Acceptance I(We), Timothy J. Tulon, hereby accept and agree to be bound by all terms and conditions of the provisional variance granted by the Agency in matter IEPA 08-11 dated August 10, 2007.

Exelon Generation Co. L.L.C/Quad Cities Station Petitioner Site Vice President Title 08/10/2007 Date