ML14007A084

Response to NRC Request for Additional Information, Dated November 21, 2013, Related to the Byron and Braidwood Stations, Units 1 and 2 License Renewal Application, Byron Station Applicant'S Environmental Report. Part 3 of 15

ML14007A084
Person / Time
Site:	Byron, Braidwood
Issue date:	12/19/2013
From:	Exelon Generation Co, Exelon Nuclear
To:	Office of Nuclear Reactor Regulation
Shared Package
ML14007A078	List: ML14007A080 ML14007A081 ML14007A082 ML14007A083 ML14007A084 ML14007A085 ML14007A086 ML14007A088 ML14007A089 ML14007A090 ML14007A091 ML14007A092 ML14007A094 ML14007A105 RS-13-282, Response to NRC Request for Additional Information, Dated November 21, 2013, Related to the Byron and Braidwood Stations, Units 1 and 2 License Renewal Application, Byron Station Applicant'S Environmental Report. Part 4 of 15
References
RS-13-282
Download: ML14007A084 (343)

Text

Byron Environmental Audit -Request for Additional Information Response Question #: HCR-1 Category:

Historical and Cultural Resources Statement of Question: Provide a series of aerial photographs of the entire plant site and associated transmission line(s) (during pre-construction, construction, and post-construction periods) looking at levels of disturbance that occurred during construction or since operation, whether any historic structures or possible sites are present on the property, and identifying any recent projects that will require a review of additional documentation.

Response: Aerial photographs of the plant site during the pre-construction and construction time frames are attached to this response.

Also, in a letter dated February 1974, the Illinois SHPO stated that no cultural or historical sites of significance were located within the Byron project boundaries.

A copy of the 1974 letter from the Illinois SHPO to the U.S.Atomic Energy Commission is attached to this response.There are no ongoing or anticipated construction projects at Byron that would require review of additional documentation.

List Attachments Provided: 1. Aerial photographs

2. Letter from Illinois State Historic Preservation Officer (A. Dean) to U.S. Atomic Energy Commission (D. Muller) regarding review of environmental reports for Braidwood, Byron, and Clinton Stations, February 1974.

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The following drawing specifically reference Map Of Archaeological Site DOI STAT I LLI NHotS DEPARTMENT OF CONSERVATION SPRINGFIELD 62706 AA I> N *FEB 1 197 Docket Nos.: STN 50-454, STN 50-455 ST) 50-456, STN 50-457 STN 50-461, STN 50-462 Mr. Daniel R. Muller Assistant Director for Envircnmental Directorate of Licensing U. S. Atomic Energy Coi.ission W~ashington, D. C. 20545 Proj ects

Dear M!r. Muller:

The envirorn.ntal reports prepared by Co-orvealth Ed+/-son cn Braidwood Staticn (Units 1 acd 2, Will Ccunty) and Byron Sta-ion (Units 1 ard 2, Ogle County) and Illinois Power Co=pany's environmental report on the Clinton Power Station (Units 1 and 2, De Witt County) have been reviewed.This review was made to deter-_ine what effect, if any, undertaking the Evrom, 3raid-ood, or Clinton projects would have on cultural and histori-cal si:es of significance within or adjacent to project work boundaries.

Archaeological, studies conducted on the project sites by members of the Illinois Archeeclcgical Survey for Illinois Power and Co=onwealth Edison indicate the existence of archaeological sites within the boundaries of each of the three projects.

Results of the archaeological surveys for each site should be included in the final environmental statements.

The final statements should also indicate Co=onwealth Edison's and Illinois Power's plans for archaeological salvage of the lochted sites and their plans for recording and salvage of archaeological sites which may be discovered during project construction.

It has been deternined that, with the exception of the aforementioned archaeological sites, no cultural or historical sites of significance are located within the projects' boundaries.

No National Register of RECYCLED PAPER H-1 Mr. Daniel R. Muller-2-February Historic Places sites are found w4thin the project boundaries of the Braidwood, Byron, or Clinton Power Stations,..

Director State Historic Preservation Officer ATD:gjf cc. Ir. George Monret, Building l-A, Environmental Statem.ent Projects.Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 Hr. Charles Bareis, Illinois Archaeolcgical Survey, IC9 Davp.nporz Hall, University of Illinois, Urbana,. Illinois 61601.Mrs. Ann Webster Smith, Director, Office of Cozpliance, Advisory Cou..cil on Historic Preservation, Washington, D. C. 20240 H-2 Byron Environmental Audit -Request for Additional Information Response Question #: HCR-2 Category:

Historical and Cultural Resources Statement of Question: Provide a copy of the avoidance measures recommended by the Illinois State Historic Preservation Office (IL SHPO) for construction of Byron as referenced in Section 2.11.2 of the ER.Response: Attached is Section 2.6.1 from the Byron Station ER-OL, as amended January 1983 (CoinEd 1981 a, p. 2.6-1). This section states (1) that "[i]t was recommended

[in the 1974 Phase II Archaeological Report] that the sites along the Rock River in the river screenhouse area be fenced and construction crews be instructed to remain 50 feet from the fence in order to avoid impact during construction activities," and (2) that"[a]rchaeological site Oq-1 53 [sic], the only site near any construction activity, was fenced in the fall of 1976." [Note: While the ER-OL refers to archaeological site Oq-1 53, current SHPO records refer to the same site as 11OG153.]Also attached is a letter dated September 18, 1974, in which the Illinois SHPO acknowledged receipt and review of the Phase II Archaeological Report for the Byron Station site. The letter notes that "safeguards are being taken to protect the known archaeological sites and that construction crews will be instructed to remain a minimum of 50 feet from them." A copy of the Phase II Archaeological Report is attached to the response to Audit Needs Question HCR-12.List Attachments Provided: 1. Section 2.6.1 from the Byron Station ER-OL, as amended January 1983 (CoinEd 1981a, p. 2.6-1).2. Letter from Illinois SHPO (A. Dean) to Commonwealth Edison (J.McCluskey), September 18, 1974.

Byron ER-OLS AMENDMENT NO. 4 JANUARY 1983 2.6 REGIONAL HISTORIC, ARCHAEOLOGICAL, ARCHITECTURAL, SCENIC, CUTURAL, AND NATURAL FEATURES This section reviews the findings of the historical study and the archaelogical surveys of both the Byron Nuclear Generating Station -Units 1 & 2 (Byron Station) site and the transmission line rights-of-way.

2.6.1 Plant

Site There are no sites on the station property that are included or are eligible for inclusion in the "National Register of Historic Places" (Federal Register 1977a, 1977b), the "National Registry of Natural Landmarks" (Federal Register 1975; Resseguie 1977), or the other listings of locally significant sites.Although six historic sites were listed for Ogle County in the"National Register of Historic Places" (see Table 2.6-1), none of these will be affected by the Byron Station. The "Historic American Buildings Survey" (Ison 1977) lists three structures in Ogle County (see Table 2.6-1), and again none of these will be affected by the Byron Station. The "Pictorial Archives of Early American Architecture" (Ison 1977) lists four buildings in Ogle County, none of which will be affected by Byron Station (see Table 2.6-1).Many areas of local historical interest, however, do exist in the area. Table 2.6-2 lists and briefly describes these historic sites and markers located within 10 miles of the site as supplied by information from various local sources (see references).

In February 1974, Anthony T. Dean, State Historic Preservation Officer for Illinois, stated that no cultural or historical sites in the area would be affected by Byron Station. A copy of his comments is included in Appendix 2.6A.An archaeological survey of Byron Station was conducted in June 1973 by the University of Wisconsin

-Milwaukee, a member institution of the Illinois Archaeological Survey. Seven previously unrecorded archaeological sites and one previously recorded site were encountered.

In 1974 test excavations were performed to further evaluate the sites so that procedures could be developed that would preclude any potentially harmful effects.It was recommended that the sites along the Rock River in the river screenhouse area be fenced and construction crews be instructed to remain 50 feet from the fence in order to avoid impact during construction activities.

Archaeological site Oq-153, the only site near any construction activity, was fenced in the fall of 1976. In September 1974, the State Historic Preservation Officer of Illinois stated that no archaeological sites would be disturbed by the construction of the Byron Station. A copy of his comments is included in Appendix 2.6A.2.6-1 Byron ER-OLS AMENDMENT NO. 3 MARCH 1982 AMENDMENT NO. 4 JANUARY 1983 2.6.2 Transmission Line Rights-of-Way The historical sites of interest for the Byron East to Cherry Valley-Nelson transmission line right-of-way and the Byron South to Cherry Valley-Nelson transmission line right-of-way are the same as those listed in Subsection 2.6.1. The "Camling-Cline Mound Group," an archaeological site located in Section 10 of Rockvale Township in Ogle County, is being considered for nomination to the "National Registor of Historic Places." The Byron North to Wempletown right-of-way is adjacent to the site 4 but does not impact on it. This right-of-way also crosses into Winnebago County where the "National Register of Historic Places" lists 13 sites (see Table 2.6-3). These sites will not be affected by the Byron North to Wempletown right-of-way.

There are no sites listed on the "National Registry of Natural Landmarks" for Winnebago County.Archaeological surveys were conducted on these transmission line rights-of-way out of Byron Station. The results of the surveys were submitted to the Illinois State Historic Preservation Officer, and his assessment of transmission line impacts on 3 historic and cultural resources is contained in letters dated May 12 and July 16, 1981. Copies of these letters were submitted in response to NRC Question 310.4, which is part of Amendment No. 1 to this ER-OLS.The Byron North to Wempletown transmission line will be visible at the Rock River crossing.2.6-2 Byron UR-OLS STATE OF ILLINOIS S 'o1914 Wy HIUiIl DEPARTMENT OF CONSERVATION I.4t% .SIAEII ('I~ll I II III 9Ip.Jl c 11% SIA 111111 14CIIII III. 1".-iI'IINGIFIFILn 62706 ChIICAGO tIrImc.-hiin

s. MICIhIGAN AVE. 6l060S September 18, 1974 Mr. J. P. McCluskey Director of Environmental Affairs Conmionwcalth Edison Post Office Box 767 Chicago, Illinois 60690

Dear Mr. McCluskey:

On August 22, a his office received the Phase II Archaeological Report for the Byron Station sitc. The Report has been reviewed and the Department is satis~led that no archaeological sites will be d.Lsturbecd by coi1StrUt:tion activiLies dtaiIL.1ed in your transmittal leiter and survoyor's

mi

p. It iS noted that safeguards are being taken to protect 0tW kno,'n arh.eological sites and that construction cre%.:s will be iinstructed Lo remain a u1inimniu,:

of 50 feet from them. Thank you for this opportunity of review and comment.( S: w rely, Di re/. tor Statre listorlc Preservaition offier ATD:tmm Yk- )aw Byron Environmental Audit -Request for Additional Information Response Question #: HCR-3 Category:

Historical and Cultural Resources Statement of Question: Provide any maintenance or avoidance measures currently in place for site 11 OG153, or any other site within Byron site boundaries.

Response: Specific avoidance measures have not been implemented for site 11OG153 or other archaeological sites within the Byron owner-controlled area because the Final Environmental Statement related to operation of Byron specifies no mitigation requirements for historic and archaeological sites on the Byron plant site (NRC 1982, p.9-5) and states that "[o]peration of the plant will not result in any significant impact on historic and archeological sites in the area" (NRC 1982, pp. iv and 5-17).Copies of the pertinent pages from NRC 1982 are attached.List Attachments Provided: 1. Page iv from NRC 1982 2. Page 5-17 from NRC 1982 3. Page 9-5 from NRC 1982

a. The additional generating capacity provided by operation of Units I and 2 of the Byron station will result in a significant savings in system production costs and will assist CECo in maintaining a diverse i'&A of generating resources (Sec. 2).b. The land use impacts will be small (Sec. 5.2).c. The Byron station will draw most of the water it consumes in oper-ation from the Rock River; a small portion for the makeup water system will be pumped from wells. The average net use will be about 1.3 m 3/sec (47 cfs), which is about 1% of the average annual flow;therefore, no water-use impacts are expected (Sec. 5.3.1).d. The chemical, thermal, and other waste discharges into the Rock River will be rapidly assimilated; hence, no adverse impacts on downstream water users or aquatic biota are expected (Secs. 5.3.2 and 5.5.2).The staff expects that applicable standards will be met.e. The plant area does not alter the flood plain of the Rock River or its tributaries in the vicinity to affect their flood-prone areas (Sec. 5.3.3)f. There will be a visible plume extending from the cooling tower most of the time; however, the ground-level fogging and icing caused by this plume will be negligible (Sec. 5.4.1).g. The potential for impacts on the terrestrial ecosystem, which could be caused by operation of the cooling-tower emissions, bird impaction, noise, or trar,imission-1inp pffpcts, ha, hPen e, JT cnd no ddi-tional impacts are expected (Sec. 5.5.1).h. The potential for impacts on the aquatic ecosystem, which could be caused by impingement or entrainment, thermal discharges, or dis-charges of chemical and sanitary wastes, has been examined and are expected to be small (Sec. 5.5.2).i. Operation of the plant will not have an adverse effect on any rare, endangered, or threatened species (Sec. 5.6).j. Operation of the plant will not result in any significant impact on.'--istoric and archeological sites in the ar :Re r along the transmi s-Jýs~iqn,,qrr idors" (S k k. The staff concludes that the primary socioeconomic impacts of plant operations are tax benefits and employment.

Other socioeconomic impacts of operation are expected to be small (Sec. 5.8).1. No significant environmental impacts are anticipated from normal operational releases of radioactive materials.

The estimated max-imum individual dose for a member of the public subject to the maximum exposure will be very small compared to natural-background doses. As a result, the staff concludes that there should be no measurable radiological impact on members of the public from routine operation of the plan~t (Sec. 5.9.3).3yron FES iv 5.S.I s toric.,and rArheologica Ii Sites)Opera tion of the station wi not result in,;in any cant .1. mpac t". on?.,ý historic nd.0 archeological itesO n ;teiarea(FES-.Section.

5.1)) nor along the trans-mission corridors (ER-OL. PQ 3104). However, as directed-in a letter from the State Historic Preservation Officer to the applicant (See Appendix H), care must be taken to avoid the known archeological sites in the transmission corridors during maintenance activities, and in the event that a future major ground disturbance related to the operation and maintenance of the transmission lines is anticipated at the sites, the applicant is required to consult the SHPO before taking action. The applicant shall provide copies of this correý,,,,1denc_

to NRC.5.8 Socioeconomics The socioeconomic impacts of station operation are analyzed in Section 5.5 of the FES-CP with visual impacts covered in 'Section 5.1.2. lhe primary impacts of plant operation are tax benefits and employment.

[the tax benefits are estimated to be approximately

$11 million (1981 dollars) in 1985 when the station is scheduled to be completed.

These annual revenues will be paid to nine local jurisdictions ranging in amount from $4.9 million to $10,900 (1981 doli.r_.)

as shown in Table 5.5. The plant wfli employ about 400 personnel when operatirn,, with an annual payroll of S10.9 million (1981. dollars).

Approxi-mately 25o of these will be local hires. There will also be 100 security force employees with an annual payroll of $1,450,000 (1981 dollars).

It is estimated that al.l of the security staff will be hired locally. (ER-OL, RQ 310.7.) The inflow of operating personnel will not significantly affect local services 7- .L L' -t j.': .JI ýý C!, i'eqI'U i I Io LIu L , L -UL, L u I phase of the station.Table 5.5 Byron station property taxes Taxing .urisdiction 1985 Estimated*

Ogle County $ 2,022,800 Rockvale Township 1,322,600 School District U-226 4,944,300 Byron Fire District 1,516,000 Junior College District 511 629.200 Oregon Park District 313,300 Byron Library District 45,900 School District U-220 199,200 Junior College District 52' 10,900$11,004,200 A198; 1.c1la ,'s.Sour'ce: ER-OL. No:met J. 1. I, fable 8'.2-1.l -yvr ; Lr b-/i on the Byron station property had been buried by others prior to the acquisition of the property by Commonwealth Edison and has been reported to be cleaned up in a satisfactory manner by the Illinois EPA. Additional monitoring of ground-water wells will be conducted by the Illinois EPA to monitor the effeýcts of dumping,:on.adjacent property.9.5.3.1 Aquatic (01-2, CECo-29, CECo-32)DI commented on Section 5.5.2.1. This section has been revised based on comments received from the applicant (see Appendix A). The applicant points out that neither the operational Section 316(b) demonstration study nor the concerns of the IDOC to be studied include entrainment..

The applicant has committed to keep the Rock Island Field Office of the Fisn and Wildlife Service informed of the findings from both the NPDES monitoring program and the special study addressing the IDOC concerns (according to a letter from C. L. McDonough, Commonwealth Edison Director of Environmental Assessment, to S. Chesnut, NRC Licensing Project Manager, March 9, 1982).In response to the applicant'-.

comments, the first sentence on page 5-16 has been deleted. Corrected information is in Sectinn F.5.2.2.Section 5.5.2.2 has been revised to reflect the monitoring requirements speci-fied by the NPDES permit and the applicant's agreement with the IDOC.However, while Section 5.5.2.2 has been revised, the title has not been altered as suggested because the applicability of the information is stated in the fi-rst sentence of the revised text.A new Section 5.5.Z.3 has beeo auded tc clarify the separate monitoring program being conducted under the agreemeitt between the applicant and the [DOC.%9:4' Histori Archeollogical Sites CECo-33 Ita sU not': the s taf f 's 1intent~ to e.1 imi nate~l CECb61'sý communicati on witt) the SH-P (bu,, 6i`ý!SHOan.

NRCýIb6Vfnformned if:archeologi'cail) s'Aesln the tra~nsm~issiori 0rri ,,re ~aeto 4!ý4f e ,bf tr-aivfe,)e cionX15 17 9.5.5 Radiological (CECo-35; HHS-1, -2; EPA-1, -2, -5; IDNS-3, -4, -5)In response to CECo and IONS, the staff's judgment that the calculated results of the consequences are more likely overestimates is based upon the following:

(1) The release fractions of fission products, shown in Table 5.11, are believed to be conservatively high for those radionuclides that are dominant risk contributors.

This is due to the complexities of modelling more accurately natural plate-out and aerosol agglomeration and settling tendencies within containment.

(2) The meteorological dispersion model employed is believed to be conservative.

(3) The staff's estimates of the effectiveness of protective actions, particul~arly evaCUation times, are believed to be conservative.

Byron FES.9-5 Byron Environmental Audit -Request for Additional Information Response Question #: HCR-4 Category:

Historical and Cultural Resources Statement of Question: Provide a description of how historic and cultural resources are considered in land disturbing activities.

Response: Exelon Generation has adopted a procedure applicable to nuclear power plants that provides a process for screening of proposed activities by responsible individuals to determine whether further evaluations for environmental impacts are warranted.

[EN-AA-103]

Examples of activities that would qualify for further evaluation and that could involve land disturbance include[EN-AA-103-F-02]:

• Changes to or installation of storm drains, ditches or swales (e.g., changes to culverts, removal/addition of vegetative cover, changes to grade, blocking stormwater pathways)" Changes to or installation of dikes, dams or appurtenances" Construction, demolition or abandonment in place of any site or non-generating facility buildings or structures" Dredging or silt removal from intake structures or other structures

• Land disturbance of >1 acre for any one activity, well drilling, soil boring, or changes that would alter storm water runoff* Paving of previously unpaved areas Activities determined to warrant further evaluation are reviewed by Environmental personnel to determine whether the actual or potential environmental impacts of the activity are bounded by the environmental basis for the nuclear power plant. [EN-AA-103-F-02]

In the case of a land disturbing activity, the cultural, historical and paleontological resources environmental basis for Byron Station has been summarized in a Cultural Resources Management Plan (CRMP), which identifies previously disturbed areas and the locations of known archaeological sites within the Station's boundaries.

If the actual or potential impacts of excavation associated with the activity are not bounded by the environmental basis, then a supplemental cultural resources survey may be performed based on consultation with the State Historic Preservation Officer. [EN-AA-103-0001]List Attachments Provided: None Byron Environmental Audit -Request for Additional Information Response Question #: HCR-5 Category:

Historical and Cultural Resources Statement of Question: Provide a description of the process for inadvertent discovery of historic and cultural resources.

Response: If cultural, historic or paleontological resources are uncovered during an ongoing excavation at the Byron Station, the work would be stopped, appropriate notifications would be made, a cover would be positioned to protect the exposed resources from the elements, access to the area would be controlled with barriers and/or signs, and work would not resume until authorized by Environmental personnel.

Also, Environmental personnel would coordinate the salvage or disposition of any recovered resources.

[SA-AA-1 17]List Attachments Provided: None Byron Environmental Audit -Request for Additional Information Response Question #: HCR-6 Category:

Historical and Cultural Resources Statement of Question: Provide a description of ComEd's transmission line management plan, including:

timing of activities, danger tree removal and other clearing, inspections and repair activities conducted by ground vehicles, standard operating procedures or guidelines for the applicant and any contractors; erosion control procedures, technician training programs, and any regulations that restrict maintenance activities (e.g., looking for activities that could affect depth of disturbance, if any disturbance is necessary along the corridor).

Response: In the Byron Station License Renewal ER, Exelon Generation applied the NRC regulations and guidance that were in effect at the time the Byron and Braidwood License Renewal Application (LRA) was submitted (May 2013) to define for which transmission lines environmental impacts should be analyzed.

Under the previous regulations and guidance, the in-scope transmission lines for Byron license renewal included the transmission lines that were constructed with the station to connect it to the regional electricity grid. Such lines, which are all owned and operated by CornEd, are identified in the Byron License Renewal ER as follows:* Byron to Wempleton (345-kV line extending north from the Byron switchyard)

• Byron to Cherry Valley (double circuit 345-kV lines extending east from Byron switchyard)

• Byron South (345-kv line extending south from Byron switchyard)

In June 2013, after the Byron and Braidwood LRA was submitted, the NRC finalized regulations that changed the requirements and guidance defining which transmission lines would be within the scope of license renewal environmental review. Under the new regulations, in-scope transmission lines are defined as transmission lines that connect the nuclear power plant to the substation where electricity is fed into the regional power distribution system and transmission lines that supply power to the nuclear plant from the grid [10 CFR 51, Appendix B to Subpart A, Table B-i, Footnote 4]. This definition is further explained in the Statement of Considerations for the final rule, which states that"those transmission lines that would not be impacted by a license renewal decision (i.e., those lines that would not be dismantled or otherwise decommissioned as a result of a plant terminating operations because its operating license had not been renewed) are considered beyond the scope" for the license renewal environmental review. [78 Federal Register 37296 -37297; June 20, 2013]Because the NRC will now apply the new regulations to define the scope of transmission lines for which environmental impacts are analyzed in the License Renewal Supplemental Environmental Impact Statement for Byron Station, Exelon Generation has revisited its original evaluation of the in-scope lines. Electricity generated at Byron Station is transformed from generator voltage to a nominal 345-kV transmission system voltage by the main power transformers.

The main power transformers are connected via intermediate, on-site transmission lines to the on-site 345-kV Byron Station switchyard.

The location of the intermediate transmission towers on the site property is shown in Byron UFSAR (Exelon Nuclear 2010a), Figure 8.2-3. For ease of reference, a copy of the figure is attached to this response.

Based on this information and that there are no other transmission lines that would be dismantled or otherwise decommissioned as a result of terminating operations at Byron, Exelon concludes that, under the new regulations, the intermediate, on-site transmission lines are the only in-scope transmission lines for the Byron license renewal environmental review. These transmission lines are located entirely within the station's protected area. Grounds management practices for that area are described in the Request for Additional Information Response HCR-7.List Attachments Provided: Byron UFSAR (Exelon Nuclear 2010a), Figure 8.2-3 REVISION 9 DECEMBER 2002 WEMPLETOWN z F2KCE 0 Un-J IL se, L z IN L=G, 0.9" 310" EL 230*-*0)z 0C E53ISAL I :*CIRCULATING La.J IflY. IIATER I ' WATER coOIN j :: _pWupOUSt 31i0K STAlION UPDATED FINAL SAFETY AALT= REPORT sa- -g.-FlGU9 234 VOE1 PLAN Byron Environmental Audit -Request for Additional Information Response Question #: HCR-7 Category.

Historical and Cultural Resources Statement of Question: Provide information on management around less-developed areas of the plant site, especially near known historic and cultural resources or near unsurveyed areas, if applicable.

Response: Vegetation control at Byron station is the responsibility of the Facilities Maintenance Department.

The following guidelines are used as the basis of operation for this activity.* Regular -"Yard" areas both inside and outside of the PA are generally mowed on a regular basis to maintain a height of 6" or less. (e.g., training, plant entrance, shooting range)* Secondary

-Security sensitive areas inside and outside the PA are mowed less frequently to maintain vegetation at 12" to 16" or less. These areas are located outside from the center of the plant, and their boundaries depend on defensive strategies of the security force. Security supervision contacts facilities maintenance if the vegetation becomes overgrown to a point that it may hinder their activities.

Facilities staff and security management tour these areas as needed to discuss possible issues or special requests. ( e.g., along south road, natural draft cooling towers -- East side)* Outlying -These are areas that are of less significance to security and the overall aesthetics of the site, but warrant some degree of vegetation control for work access, security inspections, or noxious weed control. These areas have a goal of being mowed twice per year. ( e.g., North of main parking lot, outlying areas of shooting range)* Blowdown -The blowdown line and 345 kv line to RSH areas have a goal of being mowed at least twice per year with more frequent mowing dependent on work activities and inspection access. These areas are also monitored for tree growth/infringement on the power lines." Less developed

-Less developed, unsurveyed areas of station property not encompassed in the areas previously described are maintained only in response to special requests.Note: The frequency of mowing activities is subject to weather, other work load, plant priorities, and staffing levels.Note: The known historic and cultural resources indicated on the map in the Cultural Resources Management Plan are not maintained in any way differently than any of the other landscape in the immediate surrounding area.Ust Attachments Provided: None Byron Environmental Audit -Request for Additional Information Response Question #: HCR-8 Category:

Historical and Cultural Resources Statement of Question: Provide documentation of construction projects that have occurred on the property since the construction of Byron to determine how historic and cultural resources were considered.

Any documentation demonstrating compliance with existing environmental procedures would be useful. What materials are used by the staff to determine whether the SHPO should be consulted?

Response: No construction projects have occurred at the Byron Station since existing procedures requiring environmental review of such projects were implemented, which occurred a few years after the merger in October 2000 of Unicorn Corporation and PECO Energy Company to form Exelon Corporation.

Prior to the merger, documentation of environmental reviews associated with construction on the Byron owner-controlled property was not archived.For future reviews of proposed land-disturbing construction projects, Byron environmental personnel will review the cultural, historical and paleontological resources environmental basis for Byron Station, which has been summarized in a Cultural Resources Management Plan (CRMP). The CRMP identifies previously disturbed areas and the locations of known archaeological sites within the Station's boundaries.

If the actual or potential impacts of excavation associated with the project are not bounded by the environmental basis, then the State Historic Preservation Officer would be consulted concerning the need for a supplemental cultural resources survey. [EN-AA-103-0001]

List Attachments Provided: None Byron Environmental Audit -Request for Additional Information Response Question #: HCR-9 Category:

Historical and Cultural Resources Statement of Question: Provide a percentage of disturbed and undisturbed land within the Byron Site.Response: Exelon Generation believes that areas occupied by the power block, switchyard, and other supporting facilities (approximately 154 acres) [Byron UFSAR Section 2.4.2.3, pp. 2.4-6a to 2.4-7] as well as the pipeline corridor (approximately 384 acres) [Byron UFSAR Section 2.1.1.2, p. 2.1-2] were all disturbed by original construction of Byron Station. These areas (approximately 538 acres total) represent 30 percent of the total Byron Station land area (approximately 1,782 acres) [Byron UFSAR Section 2.1.1.2, p. 2.1-2]. Approximately 47 percent of the total Byron Station land area (840 acres) has been leased for agricultural purposes.

Such land is considered disturbed because most of it is tilled. The remaining 23 percent of the Byron Station land area (404 acres) is undisturbed land.List Attachments Provided: None Byron Environmental Audit -Request for Additional Information Response Question #: HCR-10 Category:

Historical and Cultural Resources Statement of Question: Provide information about the percent of leased land within the Byron site; how much of the land within the Byron site is directly owner-controlled?

Response: The Byron Station occupies approximately 1,782 acres of land. This area consists of the main site area and the pipeline corridor to the Rock River. The main site area occupies approximately 1,398 acres, while the corridor occupies the remaining 384 acres. [Byron UFSAR Section 2.1.1.2, p. 2.1-2] Approximately 840 acres (47 percent) of the total land area occupied by the Byron Station is leased for agricultural use. The power block, switchyard, and other supporting facilities under continuous surveillance occupy approximately 154 acres (9 percent) of the total station land area. [Byron UFSAR Section 2.4.2.3, pp. 2.4-6a to 2.4-7]Regarding control of leased land within the Byron site, Exelon Generation generally retains an unrestricted right to enter, use, and dispose of the leased land for its business purposes and in the event of emergencies.

Also, subleases are not allowed, and leases typically restrict use of the leased land solely to a designated purpose, such as for farming and agricultural purposes, for cultivating crops, and/or for pastureland.

In addition, some leases may prohibit certain specific activities on the leased land, such as removing top soil, changing the original ground grade level, altering the natural water drainage pattern, and installing irrigation systems.List Attachments Provided: None Byron Environmental Audit -Request for Additional Information Response Question #: HCR-11 Category:

Historical and Cultural Resources Statement of Question: Is there any formal cultural resource training for Byron staff?Response: Byron Station personnel receive no formal cultural resources training.List Attachments Provided: None.

Byron Environmental Audit -Request for Additional Information Response Question #: HH-1 Category:

Human Health Statement of Question: Provide NPDES monthly discharge monitoring reports for the past five years.Response: The NPDES monthly discharge monitoring reports for all months of years 2008 through 2012 and January through July 2013 are provided.List Attachments Provided: 1. NPDES monthly discharge monitoring reports for January 1, 2013 through July 31, 2013.2. NPDES monthly discharge monitoring reports for January 1, 2012 through December 31,2012 3. NPDES monthly discharge monitoring reports for January 1, 2011 through December 31,2011 4. NPDES monthly discharge monitoring reports for January 1, 2010 through December 31,2010 5. NPDES monthly discharge monitoring reports for January 1, 2009 through December 31,2009 6. NPDES monthly discharge monitoring reports for January 1, 2008 through December 31, 2008 Exelkn.Exelon Generation Company, LLC www.exeloncorp.com Byron Station 445o North German Church Road Byron. IL 61010-9794 February 25, 2013 LTR: BYRON 2013-0029 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report.In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number IL0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of January 1, 2013 through January 31, 2013.Special Condition 14 of the NPDES permit requires the station to weigh the copper anodes at the end of the zebra mussel control season and to include the total mass of copper used in the discharge monitoring report. The zebra mussel copper ion skids were shut down on December 26, 2012. The anodes of the OA copper ion skid were removed and weighed on January 24, 2013. The anodes of the OB copper ion skid were removed and weighed on January 24, 2013.The total mass of copper used for zebra mussel control was 221 pounds.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Benj M.2 a Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEIADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN. 7.. r",.,I/l:MU OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER A01 -0 DISCHARGE NUMBER MONITORING PERIOD MMI/D/YYYY MM/DDFYYYY FROM 01/01/2013 TO _ 01/31/2013 1 DEMINERAUZER REGENERATE WASTE (001A)External Outfall NO DISCHARGE ED ...PRMTRVALUE VALUE UIS VALUE VALUE VALUE UNIASYSXIO TYPE Sld .T tlS s e d dSAM PLE .. .....< .3 <11.3 19001/30 08 Soilds, Total Su d MEASUREMENT Effluent Gross toQIRMD.AG Chromium, hexavalent SAMPLE (as Cr) MEASUREMENT Effluent Gross EQIM Chromium, total SAMPLE (as Cr) MEASUREMENT 010341 0 Effluent Gross Copper, total SAMPLE (as Cu) MEASUREMENT 0104210 Effluent Gross iron. total SAMPLE (as Fe) MEASUREMENT 010451r0 Effluent Gross WRE lIEI Lead, Total SAMPLE (as Pb) MEASUREMENT 01051 10 Effluent Gross ELI-Nickel, total SAMPLE ....500 (as Ni) MEASUREMENT Effluent Gross wm, 9 N AM E lrTTL E I *:e dfy und erpnl ty o f taw t sat ft do mum e rd an d al an, ctuncif w er e pre ard under m y T E L E P H O N E D A TE PRINCIPAL EXECUTIVE OPFRCER d uraction or auislo in a ce with a system designed to assre thst qualied peimone propert gamfer anm evakft the information suxmated Based an mil hmfy of the person or persons-El Benjamin P. Youmnan who manage the system, or stose persons dfmt"y easpos for gathering the informatin, Uthe -0212512013 inotmwsti submitted Is. to the best of my Iknowledge and belef. true. accurate.

and captle 9 I am IGNA RE AINCIPLE Plant Manager aware tha the am ssgnificant penalties for sutm)ing false inmation, bi1dkng the possbey of EXECUTIVE CER OR MMIDDJYYYY

• rEe OR PMMTW fe and lt f violations.

AUTHORIZED AGENT CD COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Relevence all attachments her)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow exIsted 31 of 31 days durng this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMI&ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfietd Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoo CoxIENV SPEC DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD MM/DD/IYYYY MM/DDIYYYY FROM 01/01/2013 TO 01/31/2013 DEMINERALIZER REGENERATE WASTE (001A)External Ouffell* NO DISCHARGE

...I MEASUREMENT SAMPLE MEASUREMENT PRINCIPAL.

EJCECU'IVE OFFICER :gectiort or eupervioim m accordance walt a system disrned to msure that qzattted petsonret

____ ____________

Benjamin P. Youman who manage the system, or those persons ¢re~ty reSlones gasrertg the Intomialim.

the SNA. E .PIILE02/25/2013

• mfomelr eutimitted In. to the best of my knowledge end belief, truJe, acctiraete end comrpiete.I aint SGA E PI IPE_ __oPlant oManagerlmr eawaretandmnCt mnthem re 81sgnirhcant per nawltn e sihtI~ng fa]se Ittnfomltlon, Indlud~g the peabutot EXECUTlVY OFFICERuTOID AGNOR NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)I. Flows for January 2013 are estmated based on July 2012 values due to totalizers being Out of Service. The totahizers are an obsolete model and work orders are in place to find replacement totutizers and get them installed in the system.EPA Form 3320-1 (Rev 01/06) Previous ediIions may be used. 1/6/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)OMR Maeling ZIP CODE.61010 PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 r*FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 MAJOR] (SUBR 01)I IL0048313 i1 B01-0 CS I PERMIT NUMBER DISCHARGE NUMBER I MONITORING PERIOD MIMWDDYYYY I I MM/DD/YYYY STP PLANT EFFLUENT (FORMER 0019)External Outfall* * ' NO DISCHARGE rJ FROMI 01/01/2013 ITol 01/31/2013 pH I I 7.08 1 I 7.52 I 12 1 0 1 02/o30 I GR I 00400 10 Effluent Gross Solids. total suspended 00530 10 Effluent Gross-Unr , oslt or dllY 0,tL, 0.005 0.011 3 ...... U;01/01 CUN treatment plant MEASUREMENT 50050 10 Effluent Gross ,R_______

.SAMPLE SAMPLE SAMPLE MEASUREMENT NAMEFMITILE ICertify under penalty oflamw that this document and an anach~menft were prepared under nq TELEPHONE DATE PRINCPAL EXECUTIE OFFICER direction or supe,,fWWion accoranc wth a system designed to assure tha qualfied Persornnel________________

ropery gather and evalute the Inforrarton submited, Based an ny ntqur ato the person or persons 7 Benjamin P. Youman who manage the system, or those persons directly responsitle for gathering tne ionniation.

the 02t25/2013 bnfonnatio submitted Is. to the boest o my knowKedp and beWee. mw acorae. and comlpete.

I am SIGNAinE 0RINCIPLE Plant Manager aware hat there are stgnfficant paafaties for a atnining ase tornanb, InCtudnog the poesly d EXECUTIVE OFFICER OR AREA NUMBER DOR PNI ' ine and innnprlonment for Mowiag vtationat

.AUTORIZED AGENT MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 29 of 31 days during tlis month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. .. 1/6/2012 PAGE 1 PERMflTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvile, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/EV SPEC NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR),L0048313 i I C01-0 PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MMJDD/YYYY MMIDD/YYYY FROM 01/01/2013 TOI 01/31/2013 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 WWTP (FORMER 001C)External Outfall'" NO DISCHARGE PAAEE QUANTITY OR LOADING QUANTITY OR CONCENTRATION N. FIREOUENCY SML VALUE VALUE UIS VALUE VALUE VALUE UNIALYSISO TYPE Solids, total suspended MPLE 4.6 6.6 19 0 02130 24 Effluent Gross I, Chromium, hexavalent SAMPLE (as Cr) MEASUREMENT Soo Chromium, total SAMPLE ......(as Cr) MEASUREMENT Soo 01034510 Copper, total SAMPLE ......(as Cu) MEASUREMENT 50 01051 1 0 Efflnt Gross L a ,ttlSAMPLE

..... ...... Soolt50 Effluent Gross ME f&M1 (as Nil MEASUREMENT50 010671 0#"EnTnE I ceoify under penalty of law that this documet and arl acfl were peJere under my TELEPHONE DATE PRNCIPAL EFXECUinVE OFFICER diectin or supervsion In ecordance with a system designed to assure that quaffed personnel propedy gather and evalute the inforrmaonl Based on my nuiry of the person or persons 406-3700 Benjamin P. Youmen who manage the system, or those persons directly tor gathering the Infonna9on, the 815 02/25/2013 Inflonnaton submitted is. to the best of my knowledge and beloef, true, accurate.

and complete.

lam SIGNAn 0 RI 7 Plant Manager aware that them are significant penalties for submfting faise lformatilon, incluing ithe possablfty of E %CU OFICER OR AREA NUMBER MM/DD/YYYY onEo OR P nWirpEtfinenaed for nowing AUTHORIZED AGENT ODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hare)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow exsted through this outfall 12 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 1 I I NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 A'r-'N- 7nw r.~/N~tV RPI=C.DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER C01-DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY I I MM/DD/YYYY WWTP (FORMER 001C)External Outfall* *" NO DISCHARGElFROMI 011101t2013 TO 01/31/2013 i QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. SAMPLE PARAMETER O VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS OTYPE Zinc, total SAMPLE (as Zn) MEASUREMENT 500 01092 1 0 Effluent GrossI -i Flow, In conduit or thru SAMPLE treatment plant MEASUREMENT 3 5005010 --Effluent Gross RUN O li SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT AM EnITL.E t carlifyund~er enall oa law thatifi kn doumnt and all attachments were prpae under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER mcton or supenisl~

n In accance wth a system designed to assure that qualified personnel-prpe rty gathe r and eva th e in f ormna tin su b mit'tec B sd. on m y bnq by °f te p e rson or per sons -" Ski ' I 4 0 L-3 7 0 0 Benjamin P. Youman who manage the system, or those peosos directly responsible for gathering the Inforto, the 0225/2013 informatlon submitted is, to tha best l myt Itotaedge and beief, true. accurate, and complete.

I am SIGNA- E 0 RINCIPLE Plant Manager aware that them am significant penaliles for submtg [alse Inftrmation.

including the posstiliy of EXEC E FICER OR AREA TVPED ON PR ftie and ilprislorment tor Imowltg volations.

AUTHORIZED AGENT CODE NUMBER MMIDO/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmenta here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE-2 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN' 7rm. P~,wI::V QPI:tP DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER D01-0 DISCHARGE NUMBER MONITORING PERIOD Ii MMIDDIyYYYY MMIDDIYYYY RADWASTE TREATMENT (FORMER 001 D)External Outfall**NODISCHARGE FROM[ 01/01/2013 TOl 01/31/2013 i PRMTRQUANTITY OR LOADING QUANTITY OR CONCENTRATION N. FREQUENCY SML PARAMETEROFAML Solids, total suspended MEASUREMENT 0053010 0 Effluent Gross REQ0l Flow, In conduit or thru SAMPLE treatment plant MEASUREMENT 0.022 0.022 3 0 01/01 CN 5005010 1.Effluent Gross I. .iREM.. 1-_ AM , SAMPLE MEASUREMENT SAMiPLE MEASUREMENT SAMPLE MEASUREMENT "1 SAMPLE I NAM, IE/1'LJE I Cr,

• under Penalty dl law thi this document and all were prepared under my i TLPOED E PRIWCIPAL EXECUTIVE OFFICER drettion or superesion Itn ac ce wtdtM a swsore designed to assure ttat te persmw TELEPHrONE DAT property gather and evalute the Information sub itt. Based on my Inquiry dl the perso or peron 406-3700.Benjamin P. Youman who manage the system, or those persons &Bcdy respons.be fix gatherng the Wonnadon, Ie SG-n-'Ef./ 02125/2013 Information submttied Ks to the best of my ito~wiedge and belief, ltree, aceurte, and complete, I am SIN 7R "RNIL Plant Manager aware thdat thre ame sgnificant peonafes .fr submittn false infimatlon.

Including the possitety of EXECUTIVE O FFICER OR AREA NUMBER MMIDD/YYYY TVN cwýW ý ~ fbe and toptluetfor nWing volataions.

ZDAET CD COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfati 2 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1//2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT1EE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4480 North German Church Road Byron, IL 61010 A'TTN- 7nn SPEC DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 3 I PERMIT NUMBER E01-0 DISCHARGE NUMBER M Y MONITORING PERIOD MMIY MMDDYYYY STORMWATER (FORMER 001E)External Outfall* * *NO DISCHARGE E ...FROMI 01/01/2013 TO]01/31/2013 I IQUANTITY OR LOADING QUANTITY OR CONCENTRATION FREQUENCY SML PARAMETER N OFSA>1 VALUE VALUE UIS VALUE VALUE VALUE UNT X ANALYSIS TP Solids, total suspended SAMPLENT 0053010 Effluent Gross Solids. total suspended MEASUREMENT Other Treatment, Process Chromium, hexavalent SAMPLE Chromium, total SAMPLE ......(as Cr) MEASUREMENT Effluent Gross Copper, total SAMPLE (as Cu) MEASUREMENT Effluent Gross I 1 (as Pb) MEASUREMENT Effluent Gross I cardl/y under penalty of ~ thawtg this document and al were prpae under my [ 'AET [TEL"EPHONE DATE Benjamin P. Youman who manage the syste. or those persons irecly respons0e for gathering the tfornatlmr the 02M/2013 information submtedl Is. to the bet of my Imowledge and belil, true. ac-,rate, and compviee I SIGNnRE RINCIPLE Plant Manager aware that there are signtrrcant penalies for submittttng false infornatin.

inclutng the possibrblttyi

EErn FFICER OR A TTE GF .tOW lne and hrrprisiornmont for Imowtng vildations.

AUThORIZED AGENT CODE NUMBER MMIDDIYV'IY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hare)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow eisted through this outfall 0of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/162012 PAGE 1]

PERMITrEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe CoxfENV SPEC NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR),L0048313

[ EOl-0 PERMrT NUMBER DISCHARGE NUMBER MONITORING PERIOD MM/DD/YYYY MMIDDfYYYY FROMI 01/01/2013 ITo[ 01/3112013 OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 STORMWATER (FORMER DO1E)External Ouffall*

• NO DISCHARGE E ...QUANTITY OR LOADING QUANTITY OR CONCENTr'RATION N.FREQUENCY

ýSML PRMTRVALUE VALUE UIS VALUE VALUE VALUE UNIASYEXIO TYPE Nickel, total SAMPLE .........(as NJ) MEASUREMENT 0106710 J R Effluent Gross Zinc, total (as Zn) MEASUREMENT OEflue0nJt 10ros If Now Flow, In conduit or thru SAMPLE treatment plant MEASUREMENT 500501 0 Effluent Gross R 'SAMPLE SO V SAMPLE MEASUREMENT MEASUREMENT NAMENTS LE I ceA undEL penaAAy OF law tIat this do(R uent an all attachments were )epared under my ONE DATE 1. No .EXECUose E OFFICER drmcai of supervision In ascordance with i system designed to assure that quaoinhed perso.l 2 prope Sdr gather and evaPre theInfornain was disared ts monf the.pmonorpens8 Benjamin P. Yournan who manage the system. orthose peos= directly responsibl the, inform'ation.

the 02/25/2013 Information submitted Is, to the best of my knweg and bedef true. accurate, and complete.

IlamI GN Plant Manager aware got there amsre can penatdes for subndltbg false Inormation, Incuding the pa~ossbiy df EX lqTE OFAFFIC ORBE EAD/YY.. wOR and h One for knowing Violations.

AUTHORIZED AGENTERM/~fYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Closed Cooling System Drain Water was discharged this month.2. No Service Water System drain water or Fire Protection drain water was discharged this month.3. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Cleaning wastewater was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 118=12 PAGE 2 I 1 PERMrTrEE NAME/ADDRESS NAME Exelon Generation Co., LLC.ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 AT'rM. 7- r'n.=IEJM CO1fl NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)1L0048313 I 1 001-0 PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MMIDDFYYYY

_//] TO MM1DD/YYYY FROM I 01/01/2013 IO 01/31/2013I DMR Mailing ZIP CODE: MAJOR 61010 (SUBR 01) CS COOUNG SYSTEM BLOWDOWN External Outfall* *

• NO DISCHARGE EJ"

• RL~ QUANTITY OR LOADING QUANTITY OR CONCEN7TRATION N.FREQUENCY SAMPLE> <VALUE VALUE UNT VALUE VALUE VALUE UNT X ANALYSIS TYPE Temperature.

water dog. SAMPLE ....... ..... 83.1 i 01/01 ON Fahrenheit MEASUREMENT pH ~~~~SAMPLE.......

Effluent Gross Solids, total suspended SAMPLE .9 3.9 19 0 01/30 OR OOS301 0MEASUREMENT Effluent Gross A_ N w Chromium, total (as Cr) SAMPLE "O"002<01900101/07 OR MEASUREMENT 01034 1 0 Copper, total (as CS) SAMPLE en....500 MEASUREMENT Gross 19 0_01_07_O Cpnc,rtotal (as Zn) M PU flBLENTi.....

f 0.004 0.008 01/07 OR 01042 10 Effluent Gross B pope4 gather midevaluate i~ntwnafli jsirfttedL Based on myInquiry oftheperson orpersona "7 f/85463 Benjamin P. Vouman who manage tie system, or tine p0erawia dirctl repoali for gathein the bitonnatlon the- 02/25/2013 InZin, bned is to te nes of my brow'ette an te ., cut wmorete m SN F PRINCIPLE Zn) BAMPLE Plant Manager aware that theme are signiticani penaltes for submItting ilse Infomsitlon, Including the poassettyof EXECUTnV OFFICER OR AREA NUMBER El ente and npdomen fo knowing v.latRona.

A R AG COMMENTS AND EXPLANA tON OF ANY VIOflATIOhs (Reference all attachments here)1. MonitoPing data for outfall001-0 is icluded on attachment.

EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 I.a:-..4f.it NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMrrTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDIYYYY

=ý I MMIDDYYYY FROM 1 01/01/2013 TOI 01/31/2013 COOLING SYSTEM BLOWDOWN External Outfall* *NO DISCHARGE "J NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMRT-EE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfall 61010 MONITORING PERIOD i MMIDD/YYYY I FROM 01/01/2013 TO MMIDD/YYYY I----- f 01/31/2013 I* * *NO DISCHARGE M ..t I I QUANTITY OR LOADING QUAN1TTY OR CONCENTRATION FREQUENCY PARAMETER

.-_OF SAMPLE PRMTRVALUE VALUE UIS VALUE VALUE VALUE UNT X ANALYSIS TYPE Solids. Total Suspended MEASUREMENT.eEASUREMEN 0053010 Effluent Gross .R-ET Solids, Total Suspended SAMPLE OhrTreatment, Process.Complete Chromium, hexavalent SAMPLE ........(as Cr) MEASUREMENT Effluent Gross REG. ~ -. VGL .Chromium.

total SAMPLE (as Cr) MEASUREMENT E~ffluent Gross LEGUIRREM MI Copper, total SAMPLE (as Cu) MEASUREMENT Iran, total SAMPLEo.,, .(as Fe) MEASUREMENT 01045 1 0 Lead, total SAMPLE ....(as Pb) MEASUREMENT Effluent Gross NMUErTLE Icertify under iena th ddme d all and mftrrt were under my ONE DATE PRINCIPAL EXECUTIVE OFRFCEIR , recliion of supervision in ac~ordance wthU a system designied to assure tha Quaffied personnel IEHN mprletly gather and evablte the tntfonraton subiutrrifd.

BaGM on my hnquhy od the person or person A4 Benjamin P. Youman who manirage the system. or those parns decuy resporsble for gathering the M ai te 0225/2013 Infonnaton Is. to the best of my Inowledge and belief. tnhre. accurate, and cmlete, lan SIGN RE AP PRINCIPLE Plant Manager aware thait ther are significant penalfes for subnrtiltng faise Inflonnaion.

cMluding ltle possbrty of EXE UTIY OFFICER OR AREA MM/DD/YYYY IVM end Inprslonrent for knowing vi AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments herm)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastawater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/62012 PAGE 1.

PERMITIEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, 1160555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 002-0 PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MMMDDIYYYY MMMDD/YYYY FROM 01/01/213 1 F 01/31/2013 DMR Malling ZIP CODE-MAJOR (SUBR 01) CS 61010 STORMWATER RUNOFF BASIN External Outfall* *

• NO DISCHARGE I "" P'-I 1 I'.~ Lg :lV orr-QUANT17TY OR LOADING QUANTITY OR CONCENTRATION NO._FREQUENCYSAMPLE PARAMETER OFSAMPL PRMTRVALUE VALUE UIS VALUE VALUE VALUE ANALYO I TYPE Nickel, total SAMPLE (as NI) MEASUREMENT 0106710 IVR Zinc, total SAMPLE (as Zn) MEASUREMENT 0109210F Effluent Gross X , Oil end Grease SAMPLE ...MEASUREMENT 035621 0 Fltow. in conduit or tinni SAMPLE treatment plant MEASUREMENT Effluent Gross 11REUMt ,. DA.!G WENT!SAMPLE MEASUREMENT NAM~rrllrLE Icurty under penalty d awJ that tiles dooarnent ali at eta~enenls were prepared under my TLPOEDT PRINCIPAL EXECU~lrVE OFFICER diretion or srrpervlonr In accuntance wvdh a system designed to ssure that quatfied perssat____n______________

Benjamin P. Youman manage the system, or those persons decl responsible (or gahrn the lnfo~mstlon, the SIN, ..-F02521 Plant Manager aware that there are sign~acnt penaltlea for submitting false lrrmrnalin.

Includng the posblt of EXECI1V OFFICER OR ARIEAIM/DYY sypemi psas late hen Iniprsbirnment lot knowig blh.b AUTHORIZED AGENT cOD] NUMERMMD/Y_

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments haem)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastawater during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/1/'2012 PAGE 2 I ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 January 2013 Page 1 of 3 MONITORING DATA: WBD CRock River DATE Temperature mgd Flow deg F cfs 01/01/2013 67.9 19.52 3,750 01/02/2013 68.9 21.18 3,370 01/03/2013 71.8 17.65 4,070 01/04/2013 74.7 20.20 3,750 01/05/2013 74.7 25.48 3,910 01/06/2013 73.3 20.23 3,910 01/07/2013 74.9 15.29 3,420 01/08/2013 75.8 20.81 3,620 01/09/2013 75.8 20.44 3,450 01/10/2013 74.7 19.42 3,070 01/11/2013 81.5 20.22 3,300 01/12/2013 81.5 24.77 2,930 01/13/2013 68.8 20.69 3,100 01/14/2013 67.5 15.92 3,510 01/15/2013 70.6 22.20 4,540 01/16/2013 76.5 17.72 5,420 01/17/2013 76.5 20.55- .5,680 01/18/2013 76.0 19'91' 5,510 01/19/2013 77.2 25.65 3,940 01/20/2013 73.3 19.96 5,060 01/21/2013 67.3 13.94 5,850 01/22/2013 62.0 24.35 4,780 01/23/2013 64.6 20.06 5,040 01/24/2013 66.0 18.68 4,750 01/25/2013 72.0 19.19 4,580 01/26/2013 72.0 24.96 4,230 01/27/2013 74.7 20.43 4,000 01/28/2013 76.7 17.04 4,060 01/29/2013 83.1 18.76 4,340 01/30/2013 83.1 20.20 6,290 01/31/2013 71.6 22.90 11,300 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2013\January 2013 ATTACH01.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 January 2013 Page 2 of 3 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of January 2013.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 4.3 mg/L on 01/14/2013.

The CWBD TSS value was 3.9 mg/L on 01/1 4/2013.5. Rock River flow for January 2013 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in January 2013. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2013\January 2013 ATTACHO1.doc Exelkn.Exelon Generation Company, LLC www.exeloncorp.com Byron Station.4450 North German Church Road Byron, IL 61010-9794 March 26, 2013 LTR: BYRON 2013-0042 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency BOW CAS #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number I1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of February 1, 2013 through February 28, 2013.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, in P." Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIlTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe CoxIENV SPEC DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IIL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER[ MONITORING PERIOD swwwwI Mr DEMINERALIZER REGENERATE WASTE (001A)External Outfall***NODISCHARGE EJ FROMI 02/01/2013 ITO 02/28/2013 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER

-- OF_ _ __ __ __ _ SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E TYPE Solids, Total Suspended SAMPLE 2.2 2.3 19 0 01/30 08 MEASUREMENT Effluent Gross w o Chromium, hexavalent SAMPLE ...(as Cr) MEASUREMENT SIX0 Effluent Gross R .M1 Mai" W- =1-_. A Chromium, total SAMPLE (as Cr) MEASUREMENT Soo... ...o * .9.- -f"U. Cj.. ---Effluent Grossma Copper, total SAMPLE (as Cu) MEASUREMENT

500 0104210 Effluent Gross Iron, total SAMPLE.......(as Fe) MEASUREMENT 0104510 .~ 'rr~ (A *j. -~Effluent Gross Lead, Total SAMPLE (as Pb) MEASUREMENT.

50 Effluent Gross. ... .. .... ..."n .. ,..Nickel, total SAMPLE ...(as Ni) MEASUREMENT 500 Effluent Gross NAME/TTR.E Icandy under pennfy d law that Oft document and afl attachments were prepardLunderNmyDATE PRINCIPAL EXECUTIVE OFFICER dUtecaton or seupevisa In accordance with a system desged to assure thia quaified personnel prTpNey gather and evalue Vie uiom ation suWmed. Be on my lnqLt d t persco or persons 815 DATE Benjamin P. Youman who manage te system, or those piesonm dweoy mspwont for gathe Vn .Vh 03W26/2013 bdonimnm Is, to the best a my and be iel. t ,rue accu, SaF PRINCIPLE coplte Iam_______PRNCIPL Plant Manager aware Va there are sIgnificant pensaies far subminOttig ltae kdonnatai WIudg the EXECUIT OFFICER OR inn and inWpsnmen for lowing violaons.

AUTHORIZED AGENT MMDDYYYY nsa. pma AU~ORIZEDAGENT coo ___COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hare)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow eidsted 28 of 28 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/682012 PAGE 1 LU cC U)M:

0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DUR)PERM17TEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warenvtille, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, L 61010 DMR Mailing ZIP CODE;MAJOR (SUBR 01) CS 61010 I IL0048313 PERMIT NUMBER A01-O DISCHARGE NUMBER I MONITORING PERIOD MMIDD/YYYY

_____ MMIDNMYY DEMINERALIZER REGENERATE WASTE (001A)External Outfall I NO DISCHARGE EJ 'l .........

!FROMI 02/01/2013 I TO 021281013 I--i QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. F SAMPLE PARAMETER EOF TYPE> <VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Zinc. Total SAMPLE ... ........(as Zn) MEASUREMENT 0109210 Effluent Gross Flow, in conduit or thru SAMPLE 0.057 0243 3 ..01.Benami5P7Vom0.243maag3th m 03212013 E treatment plant MEASUREMENT Efneuent Gross e-d n ... bowIoat"o-s.

SAMPLE MEASUREMENT MEASUREMENT MEASUREMENT SAMPLE MEASUREMENT SAMPL.E NAMENTLE I CeEA lt under penO aAy, law dLthis (Rcumeen and at mtchmerns ere) TELEPHONE DATE PRImc'PAL EXECUTIV OFRCF-R dircton or sueso in accordlnoe with a syte dam~nd to assredud quagired persrnnel Benjamin P. Youmnan ;who manage the system, or those persons drectly responsble for gahf the the 40-7003/26=13sude is..to, the be ol my lax he an U.=m aart. an compete I, amIS E OF Plant Manager aware thn there are soilicant peruitie lor sulxtittift fase iordarnffm, intu the possMt d EX1ECUTIVER 0FFCER OR AE UBRM/DYY ni(PHRVE on finm e and hmpdsburen for lour~ft vlllos AUTHORIZE AGENT MCODEYY COMMENTS AND EXPLANA71ON OF ANY VIOLATIONS (Referenc all attac:hments here)1. Flows for February 2013 ar estimated based on July 2012 values due to totaJizers being Out of Service. The totalizars ar an obsolete model and work orders am in place to find replacement totalizers and got them installed in the system.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/6/2012 PAGE 2 mo 0n NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Wanrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC IL0048313 PERMIT NUMBER B01-0 DISCHARGE NUMBER DMR Mailing Zt.p CODE-MAJOR (SUBR 01) CS STP PLANT EFFLUENT (FORMER 0018)External Outalil NO DISCHARGE-" 61010 MONITORING PERIOD MM/DDJYYYI MM/DD/YVYYY FROMI 02/0112013 1 ToE 02128/2013 I I Il I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF_____PRMTRVALUE VALUE UNITS VALUE VALUE VALUE EX OFTYPE> < UNITSANALYSIS BOD, 5-Day SAMPLE (20 Dog. C) MEASUREMENT 0031010 -Effluent Gross 9 PH SAMPLE..7.6

' 7.36 12 0 02/30 OR MEASUREM4ENT Effluent Gross Solids, total suspended ESAMPLE 0.50 0.67 26 9.0 9.7 19 0 02/30 24 005301 0 Effluent Grosst Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT 0.006 0.00p 3 res.on..b"e0 01/01 CN Effluent Gross.....

...- -*SAMPLE MEASUREMENT SAMPLE MEASUREMENT lnomtonsbite .t it et at my .+ le :.'ledge an e, ..ti.re :+ .. ... " .., .

.... .cw.s.o. ad.c....et.

am____-,-___

__ _ __ _..__ _SAMPLE MEASUREMENT C MMEnTS LE I ceAN under penaEL I law NtA I tO documenraned all attachmntras here)pared uder T H PWKWALEXE~~iu'WE0 lMcp te-tin a, amsim in acdac with a strn esmi~i~gec to assure that wualied iWewnnel Benjamin P. Youman who manage tMe spswM or Urme iosms directy mrimeodgi for galtefig Vie Waiai the86 0-30 0342612D13 infanafm subnitt~d is, to te bsoo fmy knowledieanclbefie, true, a¢uraw, and owniete, lain SGNfE Cr PFRINCIPLE,, Plant Manager aware do t~here am penalfes for subidln false hibnalotatn, Ircludx the OFIERO AREANUERM//YY n~mm r~n an Imds~rnm fr AUTHORIZED AGENT CODE 1. Flow exdsted through this oulfall 27 of 28 days durng this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/1/2012 PAGE 1 m 0 m 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenviie.

IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE-MAJOR (SUOR 01) CS 61010 ,L0048313 PERMIT NUMBER EZZZCZZZZ MONITORING PERIOD AMMIDDIYYYY WWVTP (FORMER ODIC)Exdernal Outtal"*NO DISCHARGE E *" FROMI 02/01/2013 02/28/2013 I S QUANTITY OR LOADING QUANTITY OR CONCENTRATION N.FREQUENCY SAMPLE PARAMETER EXOFTYPE> <VALUE VALUE UIS VALUE VALUE VALUE UISANALYSIS "PE Solids. total suspended SAMPLE N..... 8.2 10.6 10230 24 MEASUREMENT 0053 10 A1.Effluent Gross Chromium, hexavalent SAMPLE Soo (as Cr) MEASUREMENT 0103210 Effluent Gross Chromium.

total SAMPLE (as Cr) MEASUREMENT 0103410 Effluent Gross Copper. total SAMPLE (as Cu) MEASUREMENT 0104210 Effluent Gross Iron. total ampL ...(as Fe) MEASUREMENT 0104510 Effluent Gross Nicead, total SAMPLE Soo.... 0 (as Ni) MEASUREMENT Effluent Gr-oss ..u....AMEn.eI catil under penmap eawo ft docturent and allatuachnue were prepared anerndy TELEPHONE DATE wapeft gathe and evalute the inonatioan submitted.

Based an mvy mqLftol ft permn or persons, 8'- i4,6-37,'BenWan9n P. Youmnan hof mtanagie ft system, of mine paw~ns dirmctly responsl for' ,aftmMn the infontation, p,.r..L 0=26=113 Irdornatin umite I s. to the baest anlyn kolati and bdl inse, acouate, and cwwlalte lain SGAR FPA LmPlant Manager fe idipso'4 IIow aware Me #we are stificsant penwtare = suabe Ifornisti.

lakln th posbhy d EXECUTIVE OFFCER OR AUARZEAGNT UME M/DYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Refernce all attachments hem,)1. There was no discharge of processed steam generator chemical cleaning wastawater durng this month.2. Flow existed through this outfall 16 of 28 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1A/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITEE NAME/ADDRESS NAME Extlon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvile, IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS WWTP (FORMER 001 C)External Outfal 61010 c m co)C)a I MONITORING PERIOD I I MMIDD/YYYY I .... ...-I' ......I FROMI 0Zo0112013 TO 0=1112013' NO DISCHARGE J --II lQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETE-rR OFPAML VALUE VALUE UNITS VALUE VALUE VALUE uN ALYSIS TYPE Zinc, tol SAMPLE ......t...o (as Zn) MEASUREMENT 0109210 Effluent Gross Flow, in conduit or thill SAMPLE --I3 --nf .. 0 101 SAMPLE MEASUREMENT SAMPLE MEASUREMENT MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT NAMElfT.E I certify under penally l law that the n en al e were p arpaed under my PRiNCIPAL EXECUlvE OFFICER dictn or supenison I accordnce wih a systn des" to assur tha TE ONE DATE Property gather and evadtee the Waffoation submlted.

Based on my inquiry of the or persons ,rAiAa 815 406-3700 Behn P. Youran who manage the syatem or mt. pomse descy mespnmsPbe lr gathering the Wnom --n. te 4012M13 kIlatian aubm-led is, to the best my mowtedge and beNe, true. acurate, and comple. I am SIGNAIRE o PRINCIPLE Plant Manager aware ta there ae SniW Penalties for Sut" false bnrnnatbt m.rddng the pmsall of EXECUTIVE OFFICER OR AREA Tomm and irnpriouninet fr vioan AUTHORIZED AGENT CODE NUMBER MM/mD/YYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmeants hem)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 2 cC 1=m NATIONAL POLLUTANT DISIRGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR MaIling ZIP CODE.MAJOR (SUOR 01) CS 61010 m IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD MJWYY MMIDD/YYYY I1111100yy RADWASTE TREATMENT (FORMER 0010)Extrmnal Outfall FROMI 02/01/2013 1 TOl 0240=13 I* *NO DISCHARGE M- ..--ln C NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMiTTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warnenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTWJ 7 fwIkiI D-DMAR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 U0 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NU MONITORING PERIOD MMIDWIYYYY L_ MM/DDJYYYY STORMWATER (FORMER 001E)External Outfall*.. NO DISCHARGEE J FROM]V 02(0112013 ITOl 02/28/2013 I I ll lS QUANTITY OR LOADING QUANTITY OR CONCENTRATION N.FREQUENCY SAMPLE PARAMETER

[ > A U A U NT A U A U A U NT XOF TrYPE VALU VALE VLUE ALU VALE iANALYSIS Solids, total suspended SAMPLE O~f~ethGrosslt.Pocs (as Cu) MEASUREMENT 01053010 Effluent Gross Solids., total s peddSAMPLE

.....[as Cu)MEASUREMENT anocs e.a Complete MASEEN Bmenja i P.os ......m.nae..hes..te.

a hs -oison dired -- ruo .b to gat.enn...i.....o--atl-.

.03/26-201 Crmu, total SAMPLE .o.s. odgn.. a (as Pb) MEASUREMENT Effluent GrossM n ea ae ht e,. nh an e.. ...u.t. ... ...............

..EO I.O....COMNTSAND1.EXPAAIO OF~ ANYe VIOLATIyONS (Referendcem all attacments hem)peae .hreium. wotasllchE OF procssed stAMP gen chemalceaning s aste water dute month.2. FTohersed thr og thisc outarge of p 28essdaystemgnrtrceia laigws e during the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 116/2012 PAGE 1]

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 Af"TIJ 7nofl,Wst.vlMUL '1 DMR Mailing ZIP CODE.MAJOR (SUDR 01) CS I 1L0048313 1 I E01-0 I !I PERMIT NUMBER I I DISCHARGE NUMBER 1 MONITORING PERIOD E MIDWYI MMIDWIYYVY 61010 M C2)CD STORMWATER (FORMER 001E)External Outfall* *' NO DISCHARGE

"" FROIl 02101/2013 I TOI 02/2812013 Il J I I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel, total SAMPLE (as Ni) MEASUREMENT 0106710 Effluent Gross Zinc, tow SAMPLE (as Zn) MEASUREMENT 0109210 Effluent Gross Flow, In conduit or thru SAMPLE treatment plant MEASUREMENT 5006010 1., .. cvs-Effluent Gross SAMPLE MEASUREMENT

_ ___SAMPLE MEASUREMENT SAMPLE MEASUREMENT t?SAMPLE lil t MEASU REMENT kAMF.~m.E I una al law that On document and aD atchments pr d my TELEPHONE DATE.XEcUnnWE OFFCER direcatn or supervvisi In accordance r th a system desgned to assure that quatfied pesatnae propety gather and evalte the IWnlonon subnitted.

iosyhe peunpai a 815 "406-3700P0rson1 Benjamin P. Youman who manage the sysiem. o those peasans dikr* resomsnLbl or gathering the bdonnutis.

Me 032013 mlonnati sa ied Is. to Vie bestS my awaedge and beldS. two. =caste. end owat. lam SIGNAIYT V O RI CIPLE Plant Manager aware da there am significasn penaties tar submtg alnse ai onamsn. bc0ianI the posýy St EXECUTE OFFICER OR AREA Inman -1 finae and imptsionment for Wowing viadedos AUTHORIZEDAGENT NUMBER COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reerence all attachments here)I. No Closed Cooling System Drain Water was discharged this month.2. No Service Water System dra-n water or Fire Protection drain water was discharged this month.3. No Turbine Buildin Fire and Oil Sump or Generic Non-Chemical Cleaning wastewater was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 8=m NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warsenville, IL 60555-5701 FACILITY Byron Nucdear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE*MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY MMIDWYYYY COOLING SYSTEM BLOWDOWN External Outfall* NO DISCHARGE FROM I 02/01/2013 I TO I 02/2812013 ATTN: Zoe Cox/ENV SPEC FREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FRSAEQ CPY PAAETROF PARAMETER

[ VALUE VALUE UNITS VALUE VALUE VALUE UNITSANALYSIS TYPE Temperature, water deg. SAMPLE ............

...... 78.3 15 0 01/01 CN Fahrenheit MEASUREMENT,' , ' ' :'Effluent Grosso w pH SAMPLE --- 8.47 8.68 12 0 01/07 GR MEASUREMENT 0040010 .r --&.r-.-Effluent Gross Solids, total suspended A E6 56 19 0 01/30 R Oi & Grease SAMPLE -.5 1.7 19 0 01/07 GR MEASUREMENT 00566 10 Effluent Gross C_,o'aiurm, total (as 0.0021 19 0 01/07AGR MEASUREMENT

...00117 0103410 Effluent Gross Copper, total (as Cu) SAMPLE .500 MEASUREMENT

.. 0 0104210 -A~%, ~ --"' ' %.1~Effluent Gross Zinc, total (as Zn) 0009 0016 19 0 01/07 OR 0109210 7W.A. n-.Effluent Gross=EfLE I cartiy uidet penalty ot law tha the document and all attachments were prepared uinder my TLPOEDAWF PRMPAL EXECUTVE OFM dclon or supenvi~o In acconsance with a system des to assure that qualified pwera'd piperly gather and e u the itonnmadan auft tted. Based on my nquiry o fte peorson of Nam4ns37 Benjamin P. Youman who manage the system, or thme persons drectly spoxWae for gattering the notniabon.

the 03/26/2013 Infonnatlon subNotted

a. to the beat o my Iknowedge and belif, trUe. sccuran and o=0"te. I am WSN UEC7 PICIPLEE Plant Manager aware at them are s!naM penas for sWnng false WnarmatftL Kding the poasility o EXEbEJFFICEROR 1vpWa -1 p , and muns~rmen for kwi vioabons.

AUTHORIZED AGENT coo NUMBER MMIDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Monitoring data for outfall 001-0 is included on attachment EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 Cn NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME txelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvile.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER i MONITORING PERIOD MMIDD/YYYY

_MWDWYYYY COOLING SYSTEM SLOWDOWN External Outhdl* *' NO DISCHARGE E".'.FROM I 02/0112013 I TOI 02128/2013 Il I1 I l At I I rv: 40 OW tEoJNlV XQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY OF SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE Oxidants.

total residual MEASUREMENT

.... 0.05 19 0 01/07 GR 3404 10-n.r...r I -0 Effluent Gross Priority pollutants total effluent SAMPLENT 5000810 ." " " .Effluent Gross Row, in conduit or lhnu SAMPLE 20.1..26.33 3 -0 0 treatment plant MEASUREMENT 50050 10 Mt -.~.~*~4 .~~'Effluent Gross Chlorine, total residual 5AMPLE ...... o00 MEASUREMENT 6131310 .... k... i-Effluent Gross HyraUe APLE 500 MEASUREMENT SAMPLE -MEASUREMENT PRxIN IAl IEX :CW11VE o FwICEF dlreetsin o ' supwvlsson in accosdance wiC a sia desge to assure stha qualilted peorisorl

___ _ _TE EP ON DATE proesly gasheand evaluese mtonal~m sunnissad Bad s dmy biuhSthe pesnioapeace 1<1 0630 Benjamin P. Youman wiso e shse SUn5 or those pemass dhreosy m&G1M for game9thein SIGNA p~E OF P 03/26/13 Plannlaaasesalaiaon submiftd t,. to She best of my knowledgde and baioS. trim. acosret, and casplta I a _ai Plnaaae ware that mhere are ahgnrnlcam peaies for autrssn aiseO Isslomiaio, nag m0he poesi~sy~

s ~ :IIE 0F fER OR AREA !NUMBER M/DYY ow peatia fe and ipbnvtlnmn for Imowina violaions.

AU11hORIZED AGENT C.ODEMI~YY COMMENTS8 AND EXPLANATION OF ANY VIOLATIONS (Refernce all attachments here)EPA Form (Rev 01/06) Previous editions may be used.1/202PG2 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DUR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, iL 60555-5701 FACILITY Byron Nuclear Power Station LOCAlION 4450 North German Church Road Byron, IL 61010 I 1lUX48313 I ---Ill.002-0 DISCHARGE NUMBER Ii DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 I PERMIT NUMBER STORMWATER RUNOFF BASIN External Outdall m 0n I MONITORING PERIOD I I M/DWYYYY I TO[MMIDO/YY-i FROM I 02101/2013 02r2SM13*** NO DISCHARGE a] ..I I O UIANTIITY OR LOADING QUANTITY OR CONCENTRATION N.FREQUENCY SAMPLE PARAMETER OF_____PRMTRVALUE VALUE UIS VALUE VALUE VALUE OFLYI TYPE SAMPLE .......Solids. Total Suspended MEASUREMENT 00530 10 Effluent Gross Solids. Total SuspendedSAPE...

Chromium, henavalant SAMPLE ......(as Cr) MEASUREMENT 0103210o Effluent Gross q Chromiu, total

,.....1 (as Fe) MEASUREMENT Effluent Grossc ra w -o n .w pp o .d.m Copper total SAMPLE (as Cu) :MEASUREMENT Effluent Gross ... .E PEgNcIPAL EXEC~fllVE OFFICER cremcttn or aup~er~skm bi acoance with a syasem des~gned to a~sasur reat quaffed persstnel r ___gahe an evaue th bronntw eae an minquiry t the peso or pe 'ru ", ,,s BejrinP oua s li, lm m ead ~l U manage the sysan., or those pem dircty rospatit fo gatherng the Intonnal.

th lan

'0/621 Plant Manager swas ma these ass siitn pewe for aubnritirg false inoIm.sn me P~ssUY EXECUIWVE OFFICER OR NUMBER IMMIDDIYYYY COMME.NTS AND EX(PLANAT1ION OF ANY VIOLATIONS (Reference all attachments here)1. No Tudeine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewatar was discharged thi month.2. No Fire Protection.

Service Waler or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612012 PAGE 1 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

U 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP COOE: MAJOR (SUBR 01) CS 61010 1L0048313

-PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDJYYYY I I MMIDD-YYVY STORMWATER RUNOFF BASIN External Outfall I

• NO DISCHARGE ...II I" .........FROMI 02/01r2013 ITO U2/2/2013 I P M QUANTITY OR LOADING QUANITIY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMdPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX A Y TYPE ANALYSIS Nickel, total SAMPLE. ...... .....(as Ni) MEASUREMENT Effluent Gross Z11c. total SAMPLE (as Zn) MEASUREMENT

_____0109210___--...

-.*.'t" Effluent Gross Oil and Grease M AMPLE ,. ,, ,,,,.MEASUREMENT 063582 10 Effluent Gross Flow, in conduit or thri SAMPLE treatment plant MEASUREMENT Effluent Gross SAMPLE ""'MEASUREMENT SAMPLE MEASUREMENT

.... .*t............'

-4 SAMPLE MEASUREMENT NAMETIT1L.E I cenriy under penalty of law that is documeot and all attadmmmers wor prepared wide my TELEPHONE DATE PNIAL EXECUIlVE OFI:CER direomn or supevsion In accordance with a system dsged to assure its qualiied personnel prolgather and evathe Information submtted.

Based on my inquiry S the person or Per.ons815406-3700N03128/2013 Benjamin P. Youan wh manage the system. or those persons d~rect reponrae for gathering me the 03A2M213 Informalion

&ubetod is. tot e best of my knowedge and befel. tare, accurate and caoplte. am I RINCIPLE Plant Manager -taw red tere ar slicant penatltes for submtitIng fale Inc wudhg the o EXEC =rEVFCER OR ,I tne and krpdslonnient for kneeinag vldations.

BRM DYv nPanmem R IM AUTHORIZED AGENT CODE NUMBER ___ DD/Yt ___COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. This discharge point was not used this month.2. There was no discharge Of Processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/1/2012" PAGE 21 0 C)

ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 February 2013 Page I of 2 MONITORING DATA: WBD CRock River DATE Temperature mgd Flow deg F cfs 02/01/2013 65.3 20.28 13300 02/02/2013 69.7 23.64 13500 02/03/2013 66.0 20.00 14700 02/04/2013 68.3 15.26 14900 02/05/2013 74.5 20.77 14300 02/06/2013 74.5 18.78 14500 02/07/2013 72.8 23.83 14300 02/08/2013 72.8 18.08 13200 02/09/2013 72.8 24.85 12600 02/10/2013 75.3 20.16 12500 02/11/2013 75.3 16.74 15400 02/12/2013 68.6 19.62 15600 02/13/2013 68.6 19.29 15300 02/14/2013 78.3 21.55 14500 02/15/2013 74.2 18.42 11700 02/16/2013 67.9 26.33 8960 02/17/2013 67.9 20.17 9090 02/18/2013 76.4 15.18 8480 02/19/2013 76.4 23.65 9130 02/20/2013 64.1 16.80 7330 02/21/2013 71.5 19.83 6980 02/22/2013 74.1 20.92 13400 02/23/2013 74.1 24.90 13200 02/24/2013 70.8 20.02 9810 02/25/2013 75.6 15.29 6390 02/26/2013 75.6 24.28 5674 02/27/2013 75.6 16.40 4920 02/28/2013 75.6 20.44 4770 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2013\FebruaryWebruary 2013 ATTACH01.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit 1L0048313 February 2013 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of February 2013.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochiorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 28 of 28 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001--0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 160.7 mg/L on 02/11/2013.

The CWBD TSS value was 5.6 mg/L on 02/11/2013.

5. Rock River flow for February 2013 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in February 2013. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt2013\FebruaryWebruary 2013 ATTACHO1.doc Exelon.Exelon Generation Company, LIC www.exeloncorp.com Nuce Byron Station ear.445o North German Church Road Byron, IL 61010-9794 April 18, 2013 LTR: BYRON 2013-0049 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency BOW CAS #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number IL0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of March 1, 2013 through March 31, 2013.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments BEST COPY AVASLA V PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenviie, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)OMR Mailing ZIP CODE'MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER DI S A01-0 DISCHARGE NUMBER[ MONITORING PERIOD MMIDD/YYYyI MMA)DDYYYV DEMINERALIZER REGENERATE WASTE (081A)External Outhfll* NO DISCHARGE EJ FROMI 03/01/2013 TOI 03131/2013 I Byron. IL 61010 ArlN: Zoo CoyJENV SPEC ______________

___________________

___QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF 8ML VALUE VALUE UNITS VALUE VALUE VALUE UNIT EX TYPE SAMPLE...

.........

<0.8 <0.9 19 0 01/30 08 Solids. Total upened MEASUREMENT 00530 10 , p T T -Effluent Gross .m-4 ý~At Chromium.

hexavalent SAMPLE ... ..(as Cr) MEASUREMENT Soo Effluent Gross awn.___, f'-, Chiromium, total SAMPLE ...(as Cr) MEASUREMENT So-0103410 14 j7.~Effluent Gross -Agj ~ '-I copper, total5P0 (as Cu) MEASUREMENT 500 Effluent Gross n. .......,-- ,?..Iron. total SAMPLE ..... .(as Fe) MEASUREMENT 500 0104510 .-&" .. ..,,-Effluent Gross ...:. ,. __, ___ -' 7. ... , Lead, Total SAMPLE If* ....(as Pb) MEASUREMENT0 0105110 .4'.'-mi .,,.Dav Effluent Gross Z. R. ....~. -, -.... __. ,._Nickel. total PLE ..........

.. .... .....(as Ni) MEASUREMENT, 500 0106710 B '. IMP Effluent Gross 1. 1. 41411 '- ~ .~ DIL NAHEnTrLE I cetny under penalty of law that thi document and a atachments were prepared under my TELEPHONE DATE PRPICIPAL EXECUTIVE OFFICER direct OFUP in in accdance a system designed to assure that qualified persmWl *Benjamin P. Younan ,who manage the system, or those persons directly respon.be for gatheamg the Wao.at8n.

the 04/182013 informtirato submitteid is. to the besw of my lotowiedge and belief. true. accurate.

and complete.

Iam SIGNATURE 0 ORINCIPLE

___Plant Manager aware tht0 there are signricant penalts for soubiting false Wlomaimn, hudKWg the Possibity d EXECUTIVE OFFICER OR AREA NUMBER MMIDWYYY.. an aMe and imprilionmerndtor owin violmions AUTHORIZED AGENT CODEN COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow e)dsted 31 of 31 days during this month.EPA Form 3320-1 (Rev 01/08) Previous editions may be used. 1/612012 PAGE 1 0 B3 COPY AVANLA8L'PERMrrTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warranville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)DMR Malting ZIP CODE: MAJOR (SUBR 01) CS 61010 I IL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD UMDO/VYVY MMIDDJYYYY DEMINERALJZER REGENERATE WASTE (001A)External Outaell* "NO DISCHARGE

[-] .lFROM II 03101/2013 TI o 03/31/2013 I-Il lQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS ( ANALYSIS TYPE Zinc, Total SAMPLE ..........

u...... 500 (as Zn) MEASUREMENT 0109210 .: 3,_ .. '/ "" -" Effluent Gross ... -A. .. .,'*,, .. ... ---" ___Flow. In conduit or thru SAMPLE 0.057 0243 3 .. 0 01/01 ES treatment plant MEASUREMENT 500501 0 q. q. g.to-E~ffluent Gross 'jjjý -______ ýo .. ~ ... ~ '.*..*.. .....:. .. ... .SAMPLE MEASUREMENT MEASUREMENT MEASUREMENT

.: ..........

.... ................4 , ,. ..;: .. .4, .SAMPLE MEASUREMENT V ...,l , ..4 P .;: ~ & & 2._ _. 4.. ....-_ _ -SAMPLE MEASUREMENT NAME/TITLE I cay under penalty l law that this document and alI attachmentS wre prepared under W TELEPHONE DATE PRINCIPAL EXECUTIVE OFRCER directo or supervsio in accadwne wM a System desigTed EP aHON Eat quaDilAm pTnEel property gather and avalte the Wniation subrmied.

Basedl on my inquby d the peosn or persons J, 815 406-3700 Benjamin P. Youman who manage te system, or fhse persons responsible for gathr" the intdoratlon.

theIPLE 04/18213 inlonmaliat submned Is to the best ol my knomledge and beliet, true, accurate, and complete.

lam bIGRWHEOFrJII__

Plant Manager aware thal there are significant palies sbnb false tftotnat.

bt Incluig the pilby of EXEdUTIVE OFFICER OR AREA NUMBER MMIDDJYYYY WOA Rp le and lnowing vltoltlms, AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. Rows for March 2013 are estimated based on July 2012 values due to totalizers being Out of Service. The totatizers are an obsolete model and work orders are in place to find replacement totalizers and get them installed in the system.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 2 BEST COPY AVAILABLE PERMITFEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road WarrenviUe, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North Gennan Church Road Byron. IL 61010 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I L0048313 PERMIT NUMBER B01-0 DISCHARGE NUMBER MONITORING PERIOD F MM/DDJYYYY L- m~oMID/Y STP PLANT EFFLUENT (FORMER 0018)Extenal Ouffall' NO DISCHARGE FROMI 03/01/2013 J TOI 03/31/2013 I I I BE*COPY AVAILABRV.

PERMITrEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvilie.

IL 60555.5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)DMR MaIling ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER MONITORING PERIOD MMIWDIYYY

_J I MMIDDVYVYY WWTP (FORMER 001C)External Outfall' **NO DISCHARGE FROMI 03101/2013 I01 03131/2013 I I a ATTN:QENC ZooCMPLE PE QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FFEQUENCV S P PARAMETEROF AML VALUE VALUE UNITS VALUE VALUE VALUE UNrIT EX ANLYISPE ANALYSIS Solids, total suspended SAMPLE .........5.A 7.2 Is 0 02/30 24 SMEASUREMENT

......Effluent Gross --4 Chromium, hexavalent SAMPLE ...... S00 (as Cr) MEASUREMENT_500 0103210 -- -Effluent Gross EVA" Chromun. total SAMPLE SIX.(as Cr) MEASUREMENT 500 01034 1 0 '.... , .- -" " -" " --J -,".. .fla. ..' .....Effluent Gross ____Copper, total SAMPLE ........ ........00 (as Cu) MEASUREMENT_50_

0104210 -,-1 Effluent.Gross.-

- "..:.Iron, total SAMPLE ...... 500 (as Fe) MEASUREMENT__

Effuent Gross -~~~~~-~ ~-Lead. total SA.... ...(as Pb) MEASUREMENT 500 01051 10 ~ ~ pt___ ~ -' ~ ~Effluent Gross J~l ..- .Nickel, total SAMPLE ....(as Ni) MEASUREMENT Soo Effluent Gross ,JIll mx,. .4t- i ---. --. -NAME/TrI'LE I ceWsj unere penally of law thatthis document and all afttahments were prepared under my PARINCIPAL EXECUTiVE OFFICER direction or suervsion in accoarance Wtth a systemn designed to assure that qeafed ersone TELEPHONE DATE Benjamin P. Youman who manage the System, or thane persons directly respnsble fmr gatherItg the birma on. W1he2013 Wonaeban sulmitted Is, to the best oa my knotedge end befief, tnue, accurate.

and ompilet. I am OF OUCIPLE Plant Manager aware that there am significant penates Ifo submitting lale Infomationa, Icluding the PGSbm d EXECUTIVE OFFICER OR AREA iwsn o n -Ase b _e and _ mp_ _ _ _ _ _ _ _ _ for _n v_ __a_ __. AUTHO RIZED AG EN T CODE NUM BER M M /D D/YYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outfail 17 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editons may be used. 1/6/2012 PAGE 1 BEST COPY AVAiLABLeF PERMI7TEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)DMR Mailing ZIP CODE, MAJOR (SUBR 01) CS 61010 I IL0048313 I PERMIT NUMBER C01-0 DISCHARGE NUMBER I MONITORING PERIOD I MM/DDYYYY I I MMrDDIYYYY WWTP (FORMER ODIC)External Outfall I *" NO DISCHARGE ED ...I I I _ I FROMI 03/01/2013 I TOl 03/31/2013 Byron. IL 61010 ATTN: Zoo CoxIENV SPEC_______________

_____________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER EX OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TYPE Zinc, total SAMPLE ....(as Zn) ME.ASUREMENT 01092 1 0 ** ~, --... ... ........~ ..dl' .'*..Ewffiuent Gross ;'g.Flow.Inconduitorthru SAM 0025 0.046 3 0 01/01 CN treatnent plant MEAREMENT 500501 0 Ui.. 'fv& .Effluent Gross F 1 .1 W all-~~SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE ME ASU REMENT NAMFnTn.LE certify under penafty of law that dus document and al aladhmwnts were prepaed unwder my TELEPHONE DATE PAINPAL EXECUlIVE OFCFIER directlon or superveion In accordance with a system designed to assure that qualiied pesmonnel popefy gathe and e#a It ft iroimalia ,ubmed. Based an my Inquir 01 tha pero o _ 04/18/2013 Benjamin P. Youman wino manage tne systerm, or tmse perons direcuy responsIe br gahern the Information.

the 8 15 406-3700 04/18,13 Iniomntm submitted Is. to Me beat 01 my knoW g and belief. true, accurate.

and Cmplee. I am SIGAp#. OFP#NCIPLE Plant Manager aware that teare a pn tor sulbmitig false Ionnafmin.

mdtuding Me posslly EXECUIJVE OFFICER OR AREANUMBER

/DDYYY tlu end Inprislonment for wmowln vileatlons.

NMEIMIDYY r'IM OR PndsMf AUTHORIZED AGENT ]CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference al attachments here)EPA Form 3320-1 (Rev 01/06) Previous edtions may be used. 116212 PAGE 2 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)0 PDýJSQPYAVAOLAB10.

NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4480 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE-MAJOR (SUER 01) CS 61010 1L0048313 PERMIT NUMBER D01-O DISCHARGE NUMBER MONITORING PERIOD MUIDDIVYYY I MM/DD/YVYY RADWASTE TREATMENT (FORMER 001D)External Outfall* **NODISCHARGE D ...FROM I 03/01/2013 I TOI 03/31/2013 I NAMEIlhlTE PRINCIPAL EXECUTIVE OFFICER Benjamin P. Youman Plant Manager 1iFmOA , NmmED I ceti"y under penalty ol law that his document and all attachments were prepared under my direcion or superviso In acordance with a system designed to assure Utat qWalified personnel property gather and evalute the information subminted.

Based on my Inquy of the person or persons who manage the system, or tose persons responsie tor gateng the intonmatlon, the Information submitted is. to the best of my knowledge and bedef, tnre. accurate.

and complete.

I arn aware that tere are sirllcarn penalties lor submitting false intonrmaon. g ft possWEt of rme and Imprislonment for nowing violations.AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)F. low existed through this outfall 10 of 31 days during the month.

BEST COPY AVAILA.,_.

PERMIrTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. UL 61010 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER OMR Mailing ZIP CODE.MAJOR (SUBR 01) CS STORMWATER (FORMER 001 E)External Outfall 61010 I MONITORING PERIOD I MMIDD/YYYY I I MMADD/YYYY

! I I __ _ I FROMi 03/01/2013 I TO 1 03131/2013 I* NO DISCHARGE F-1 """-I I ATTN: Zoo CoxIENV SPEC_____________________________

__________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OFYTYPE Sois oa up ne AMPLE ..".. .............

.... So"o"50 Solid, total suspended MEASUREMENT 00530 10 .15~~- ~ .~.t~~' tlad Effluent Gross 1T 0,,pops_..

." .." .Solids, total suspended MEASUREMENT 2.3 2.6 Is 0 01/07 OR Chromium, hexavalent SAMPLE 500.. .....50 (as Cr) MEASUREMENT Effluent Gross ____ , Chromium, total AMPLE ........(as Cr) MEASUREMENT 0103410 ! .....av 4....Effluent Gross -" .Copper, total SAMPLE SIX.(as Cu) MEASU REMENT 0104210 1. .... I... A ... , .5 1 , ."" " Effluent Gross -mims i 2 1a ~~ aw Iron, total SAMPLE ............

.....(as Fe) MEASUREMENT

_"_500 0104510 Dg. ktL : 'Effluent Gross ;" , ne0,i, .'.".-Lead, total SAMPLE ....... 500 (as Pb) MEASUREMENT 01051 1 .-Effluent Gross ":'- QC"4': -4 , " ...... :-_ AME_____E I c__tty under al of law OW Oft docurnent and all efachnmnts were prepared under my TELEPHONE DATE PRUCPAL EXECllVE OFRCER __ econ or supevson In acordance wth a system designed to assure that qualified pe.onne_propety gte and evalute fte tWmaoa subintiad.

Based an my Inqury of Me person o persons BenjamIn P. Youman who manage the syem or those petswis dnchy responsible tar gather the Itnration.

the 04/16/2013 Inration submitted is. to Ba beat of my knowledge and belie,. ue, accurate, and I am SIGNATU§I OF P PLE Plant Manager aware that Bare amre snrcant pMenast toa subnihng false infonnaon, intdin the p Ysaw wo EXECUTIVE OFFICER OR AREA an hMm fine and bipiW'iit for no'wing vaioaions.

AUTHORIZED AGENT CODE NUMBER MMD_/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Them was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow existed through this outfall 2 of 31 days during the month.3. Fire Protection drain water was discharged this month EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 BL 1 COPY .V 0:' ., PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvilie, IL 60555-5701 FACILITY -Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)DMR Mailing ZIP CODE*61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER MAJOR (SUBR 01)CS I MONITORING PERIOD I MMIDO/yVy I I MMIDDYYYY STORMWATER (FORMER 001E)Extenal Outfell* NO DISCHARGE EJ I I I .... ..... I FROM I 03/01/2013 I TOI 03/31/2013 I I Il !"I.

BEST COPY AVADLA1BLE PERMITrEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD MM1DWnYYYYI MMIDDWYYYY COOLING SYSTEM SLOWDOWN External Outfall***NO DISCHARGE E 'FROM I 03/01/2013

.TOI 03131/2013 l II I I Byron, IL 61010 ATrN: Zoo CoxIENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TYPE Temperature.

water dog. SAMPLE ...... ....... 79.0 15 0 01/01 CN Fahrenheit MEASUREMENT 00011 10 iw~ " ~ e~ --lv~~~O~M Effluent Gross. .... .pH SAMPLE N.8.41 8.62 12 0 01/07 GR;)H MEASUREMENT 0040010 A. ...6 ,. 19 0R Effluent GrsW ..Solids, total suspended AME6 56 19 0 010 OR MEASUREMENT_______________

______00530 10 -,Pmp&Mtn i E~ffluent Gross .~-.Oil & Grease SAMPLE ............

....... <2.0 3.8 19 0 01)07 OR MEASUREMENT 00556 10 Ptj Effluent Gross NIX' .... .-*,1-., .' .. ....... .tf ...l.......At.. .l .,. .:. .AMPLE ...... ... ... <0.0021 19 0 01/07 OR Chromium, total (as Cr) MEASUREMENT 0103410 "" ... .,2 Copper, total (as Cu) AMPLE ...... ........ 5 MEASUREMENT""50 01042 10 .." ..... ....EffluentGros

-41 m_____:V ~~.___Zinc. total (as Zn) SAMPLE ...... ...... 0.... 0.009 19 0 01/07 OR MEASUREMENT"0.60.9 19 01/7G 0109210 o ...E ff l u e n t G r o s s : -' .' ; ' ..', .4#, ...- " "'.MEnTLE I ceay under panaty od law thta ts documea and AD attachments wetre prepared under my TELEPHONE DATE PRINCIPAL EXECUnVE OFFICER dimbctin or supeorsin In acmcrdance with a system designed to assure owm qua1led personDAl pmpety gater and evakute information submitmtd.

Based n my inqui d te person of person Benjamin P. Youman w manage the system, orthosepeisons drectlymrMesporgaheingtheWmannatmln 04/18te13 mlonrnabon suwtsnfed is. to the basst r my Maledloage and baelef tnwo. amcurae, and coniplete.

I am SIýGNA EOF P M.E 0/821 Plant Manager aware Mat there we sgnfca penalties for s&u b g fale Infonnation.

icktding tMe possitlity d EXEC E OFFCER OR AREAER MMIDDYYYY ED OR ON ,the and 5ICfsmflwit for Icnowing vlalm AUTHORIZED AGENTEN COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hwe)1. Monitorng data for outfall 001-0 is included on attachment

!EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612012 PAGE 1 BES .OPY AVAOLABLE PERMATTEE NAME/ADDRESS NAME Exulon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)I DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I IL0048313 I l`--I 001-0 I1 I IfWCrMI I 5' nuro-I I UIQPrvInUEWCIUMVIDEn

!MONITORING PERIOD MMIDDIYYYY I I MMIDDJYYYY COOUNG SYSTEM BLOWDOWN Extermal Outlall 611NODISCHARGE r i FROM I 03/01/2013 TOI 03/31/2013 Il I Ik p QUANTITY OR LOADING QUANITFY OR CONCENTRATION NO.FREQUENCY PAAEERIN.

OF SAMPLE P I VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Oxidants.

total residual AMPLE ...... ...... ......0.04 19 0 0107 GR MEASUREMENT

0.0 4__9_0_01__7_GR

340441 0 ! ! ,j, : ...-..mp......

Effluent Gross :in1II-. '" Priority pollutants total effluent SAMPLE ...... Soo MEASUREMENT

_____________

0 5000510 Effluent Gross -EJ,., ' -:-Flow. in conduit or thru SAMPLE treatment plant MEASUREMENT 5005010 Effluent Gross Chlorine, totail residual SAMPLE ..... .Soo....MEASUREMENT H-ydrazine SAMPLE .........MEASUREMENT 500 8,13131 0 , ..:, ,,_,.." ,0 1 * : : ..." D ' .... W ke Effluent Gross WIT,: "*,.SAMPLE MEASUREMENT SAMPLE MEASUREMENT I/AME/trrLEcear uncer permaty l aw that true doc~unein anm auJ atanac ents wegre prepared unm rrmy PRINCIPAL EXECUTIVE OFFICER diection or supealon n acc=dance wth a systemn desned to aasans that quaatfe

% TELEPHONE DATE Bpejezy agather evaute the Wnn3matln SMd. ased On OyW It d the 815 406-3700 pe Benjamin P. Youman no me" the system or those persons dircly respoe for 0gatheUmt f te thG RNCIPLE01he Plnt Manaeron subesnfed Is. to the best o my ImwledPe and b10e1. tWe. accurate, and complete, I em U- .04/18 13 P awanIMaagrere a a ea o lt UTIVEreCER OR 4F NUMBER MM/DDtYYYY MI 1 fine and irsionrnient for kwwinot vioatim s AUTHORIZED AGENT CODE NUMBER I__________

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (RefeMnco all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1162012 PAGE 2 BEST COPY AVAILALr'PERM7T'EE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Wintield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN Extemal Outfal* 16NODISCHARGE Eji .J .61010 I MONITORING PERIOD i I MM/DD/YYYY ITO[MMIDDWYYYY I FROM I 03/01/2013 03/31/2013 Il !& lByron, IL 61010 ATTN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Solids. Total Suspended SAMPLE ......MEASUREMENT Effluent Gross ______ _____Solids, Total Suspended MEASURAMPLEN 0053080 -OthterTreatmnent Process 44 1. '-* ~Chromium.

hexavalen!

SAMPLE .............

e(as Cr) MEASUREMENT Effluent Gross ...,.,, Chromium, total SAMPLE ......(as Cr) MEASUREMENT 0103410 "... .. " Effluent Gross -i -. -W-. .., .' ., i .-..'" ,._,.Copper. totalSAPLE (as Cu) MEASUREMENT 0104210 ..,,,.Q411 Effluent Gross cilia.,'. -..' " " _ " =-' L, Iron. total AMPLE ........(as Fe) MEASUREMENT_______

_ ___ __Effluent Gross 1/2 &- \ Ld + -Lead, total SAMPLE .... ........(as Pb) MEASUREMENT 0105110 ý. ... , ... 043.Effluent Gross MAN ___ ~ ,~INIPLAL FTILE I oatiy undr penaly of lw 00 thi documen and al a were prepared under my TELEPHONE DATE PRINCtIPAL EXC TV OFFIC-R drectilon or 5upervis m n 8=rdartc wit a syste desotd to assreO qua iie peromenn % property gaMer and evaute the Information subrned. Based my inquiry of the peim ofrs 8615s 4)-37 Benjamin P. Youman who manage the system or those persons direcay rasponsae for gaitienng Me Infoimnatin.

Me 04/18=13 informatim is, to the best of my Wwwleda and belef, tnue. accuate, and I am SIGNA ,"F PR LE_Plant Manager aware that tere are sinificant penalties for sutumitg false Informatio.

Inluding the possiblity d EXECULTIVE OFFICER OR AREANUMBER MMDDYYYY MID) OR PRWMD -1ftne and lmprisionnent tar kowtng vilations.

AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612012 PAGE 1 B*CPY AVALAO[A!PERMITrEE NAME/ADDRESS NAME Exeton Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvilte, U 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)I IL0048313

]I PERMIT NUMBER 002-0 I DISCHARGE NUMBER 1 MONITORING PERIOD I MM/DDJYYYY I I MMIDDYYYY DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfall* ' NO DISCHARGE ( ...61010 I I I .....FROM I 03/01/2013 I TOI 0313112013 1 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel, total SAMPLE ...... ...... ......(as Ni) MEASUREMENT Effluent Gross -r-Zinc,- total SAPLE (as Zn)MEASUREMENT Effluent Gross Z""G Oil and Grease MEASRMPET_____

_________

_________

___________

Effluent Gross 111 R 60 1A. A 0,.V Flow, in conduil or thru SAMPLE ......treatment plant MEF...ASUREMENT Effluent Gross -". ...' '- .Z. .-' ... " MEASUREMENT

_____ -'SAMPLE MEASUREMENT SAMPLE MEASUREMENT NAMEMII1E I rmw* unde penalty of law that t1is docunent and sn artlactirents were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER dirction or supervisio In accorance wttm a systemn designed to msum that qualified pesonnel Benjamin P. Yournen who0 Manage the s1ptem. or ftse persona dbacWy responsia for 90eg Me fifnfm ation, th1e40-30 04/11/213 ilo..alcen su~mfted b. to the best of ray knowiedlge andI WMl. true. accurate, and cqM~e. I ain ,SIGiaI--OF P IC!PLE Plant Manager towa we wemm signifcant peruws for asmrnittin flse Iwonmk% ax",

of EXCTEOFCER OR AE 1-ir o pml In ab rpsofianar tw knowing violailns.

AUHOIEDAGN CD NUMBER COMMENTSI' AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments heow)" 1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewater during the month.!EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/212 PAE:

ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 March 2013 Page 1 of 2 MONITORING DATA: CWBD Rock River DATE Temperature CWBD Flow Flow deg F mgd cfs 03/01/2013 75.0 21.95 4,500 03/02/2013 71.6 23.79 4,410 03/03/2013 69.6 20.25 4,230 03/04/2013 71.2 15.85 4,110 03/05/2013 71.2 20.63 4,369 03/06/2013 72.8 19.84 4,130 03/07/2013 72.8 21.23 4,020 03/08/2013 71.9 19.37 4,020 03/09/2013 71.7 25.34 3,870 03/10/2013 78.3 20.19 5,370 03/11/2013 74.9 15.24 17,000 03/12/2013 74.0 20.96 23,500 03/13/2013 68.2 20.83 20,400 03/14/2013 69.3 20.14 17,300 03/15/2013 68.6 18.85 15,500 03/16/2013 72.5 25.66 15,700 03/17/2013 71.9 20.16 16,000 03/18/2013 74.7 15.88 15,800 03/19/2013 74.7 21.08 15,400 03/20/2013 70.3 19.73 14,300 03/21/2013 63.8 22.50 13,600 03/22/2013 63.1 18.06 12,800 03/23/2013 66.0 24.78 11,900 03/24/2013 74.5 20.05 11,400 03/25/2013 74.3 17.76 10,700 03/26/2013 76.1 19.53 10,300 03/27/2013 75.0 19.64 10,900 03/28/2013 79.0 18.84 11,400 03/29/2013 76.3 18.57 11,900 03/30/2013 77.5 23.73 12,300 03/31/2013 77.5 19.10 12,600 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2013\March\March 2013 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 March 2013 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of March 2013.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 10.0 mg/L on 03/04/2013.

The CWBD TSS value was 5.6 mg/L on 03/04/2013.

5. Rock River flow for March 2013 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in March 2013. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2013\March\March 2013 ATTACH01.doc Exelon.Exelon Generation www.exeloncorp.com NucleaT Byron Generating Station.4450 North German Church Road Byron. IL 61010-9794 Tel 815-234-5441 May 23, 2013 LTR: BYRON 2013-0070 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number IL0048313, issued January 24, 2011, we are submitting the Discharge.Monitoring Report for Byron Station, Units I and 2. This report covers the period of April 1, 2013 through April 30, 2013.On 4/17/13 at 13:57, the Stormwater Runoff Basin Overflow (Outfall 002) of Byron Station's NPDES permit began to experience flow conditions due to the excessive rainfall in the vicinity.

This flow event lasted until 17:20 on 4/17/13. The estimated flowrate was 1000 gallons per minute for a total flow of 203,000 gallons discharged via Outfall 002. As required per the permit, Total Suspended Solids (TSS) and Oil and Grease samples were obtained and analyzed.

The TSS results were 198 ppm and 195 ppm for an average concentration of 197 ppm. This exceeds the permit 30-day average concentration limit of 30 ppm and the daily maximum concentration limit of 100 ppm.The Oil and Grease result was 2.3 ppm. On 4/17/13 at 21:31 Outfall 002 again experienced flow conditions due to another extremely heavy rain event in the vicinity of Byron Station. This flow event lasted until 10:50 on 4/18/13. The estimated flowrate was 1000 gallons per minute for a total flow of 800,000 gallons discharged from Outfall 002 for this event. The total amount of discharge from Outfall 002 for the 2 events is 1,003,000 gallons. As required per the permit, an Oil and Grease sample was obtained and analyzed on 4/18/13. The Oil and Grease result was <1.40 ppm which when averaged with the previous result is an average concentration of <1.9 ppm. The Oil and Grease concentration met the 30-day average concentration limit of 15 ppm and the daily maximum concentration limit of 20 ppm listed in the permit.

Page 2 of 2 BYR LTR 2013-0070 File: 2.09.0411 and 1.10.0101 In anticipation of the forecasted rain events Byron Station undertook proactive measures to reduce the water elevation in the Stormwater Runoff Basin by installing an additional pump, to supplement the pumping capacity of the existing installed pumps.Unfortunately the volume of water received overwhelmed the storage capacity of the Stormwater Runoff Basin and the capacity of the installed and supplemental pumping systems. In accordance with the station's NPDES permit on April 18, 2013 the Agency was notified of this Upset event by Mr. Zigmund Karpa, in accordance with Special Condition 11 and Standard Condition 12(f)(2) of the permit. Byron Letter 2013-0057, dated 4/22/13, was sent to the Agency to meet the 5-day follow-up reporting requirement of the permit conditions.

If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Ben Vouman Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments bcc: K. Hersey -Environmental

-Cantera (electronic)

Z. Cox -Chemistry

-Byron NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DUR)PERMITTEE NAMEIADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 OMR MaIling ZIP CODE: MAJOR (SUOR 01) CS 61010 IL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD I MMIODDYYYY I .MM/DD/YYYYI DEMINERALIZER REGENERATE WASTE (001A)External Outfall***NODISCHARGE j J FROMI 04/01/2013 ITol 04/30/2013 I I *ATTN: Zoo Cox _ENV SPEC __FREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER

-EX OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE SAMPLE 2-..8 2.9 19 0 01/30 08 S~ldS ToalSusened MEASUREMENT Chromium, hexavalent SAMPLE .....So....(as Cr) ZMEASUREMENT7-Effluent Gross Chromium.

total SAMPLE ...... Soo (as Cr) MEASUREMENT Effluent Gross MUM_____Copper, total SAMPLE .............

500 (as C u) M E A S U R EM E N T _ "_ ",. "- " 0104210 .-.Effluent Gross N ,4- WW "i.. L :-D Y ýs-Iron, total SAMfPLE ....... .0 (as Fe) MEASUREMENT__________

______________

010451 0 ~ W~I~ 1 ,~Effluent Gross W",-I~ ~ -. ~ ~ -...~ -Lead. Total 500 (as Pb) MEASUREMENT 01045110 A 4:g~ w qRV ,,..:.,:.:..., *'o ....I.. ..Effluent Gross big .ci2; '"-, : 4 y .--N!"e, total SAMPLE ...... ... ......500 (as Ni) MEASUREMENT Effluent Gross KAMFnnLE i cIWilly under pWetay d lw tha1 this doument and al attacuments were prepared under U TELEPHONE DATE PRNWiPAL EXcVE OFRCER f or supervisio in an wfth a system des to a6ssure bt qafied persoTnnel prpe*y gatier and evalute the Informata submined.

Base a my inqiy the pe rm or persons Benjamin P. Younan who manage the system. or foe persms direcly ressaptie for gaitefng the the 40&37 231W03 Bmeamiin P.Vomned is, to ftan best d my Wxinae and bfiel f, true. am, geand ', I am SIGNA E OF PRI LE 05/l3/201i Plant Manager aware ha tmere am sigitkcant penaltes submitting false Inomalion.

cilding the pasalhhty d EXECUTIVE OFFIZOR O AEA NUMBER MMDDIYYY1 n Se and e anment for kng vms. AUTHORIZED AGENT ogO COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2- Flow exdsted 30 of 30 days durng this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1652012 PAGE 1* 4 , 0U 0 X NATIONAL POLLUTANT DIS!CARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exglon Generation Co., LLC ADDRESS 4300 Winfleld Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 A"Tmi, 7- t%/l.CSJI COCO%IL0048313 PERMIT NUMBER I DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I A01-0 I ......lI DISCHARGE NUMBER I MONITORING PERIOD MMIDD/YYYY I MMIDDJYYYY DEMINERALIZER REGENERATE WASTE (001 A)EFxtle Outa~lU*NO DISCHARGE EJ3 ...*1 FROMI 04101/2013 I TOI 04/30/2013 I! I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER EX TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Zinc, Total SAMPLE ..........(as Zn) MEASUREMENT 01092 1 0 2- <" '- -, ,U-, , .-.1/4.'Effluent Gross Amt.,%Flow, in conduit or thru SAMPLE 0.057 0.243 3 -. 0 01/01 ES treabnent pant MEASUREMENT

'Effluent Gross SAMPLE MEASUREMENT.o....s & -,..-.-. , a.5e4. a.>j-..,. .. 4 .. " ..... .. o" SAMPLE MEASUREMENT SAMPLE.MEASUREMENT MEASUREMENT NAKE/TITLE I costly widler penaly of law trial s documnent and all aflhadvmnls were prepared under myTLEHN DATE PA1INCIPAL EXECUTIE OFFICER d~rection or supe~sveon in accordance wait a aswam designed to assure Via quape peisonrnel-property gatrier and avaitot fth mlorruima autnifled.

Based on my siqu of the person of persons 4630 Benjamin P. Youmnan who manage fth system or the peisons directly responsailef (or gaihefn the hionaton 05IN REOr CPE________________

nwioan, sujtirntatl is. to the beao ofmy nwwledg and b".S true, accurae. and wnpleta. I 05/23/2013O PINCPL Plant Manager swame tha there sie sigificant penalties tor submtehig ini flseInfornllon, Inkiduling the powbstly of EXECUTIVE OFFICER ORNUBRMDDY Y nna O a W rm fine and foibiinttr blowing vidallomns.

I AUTHORIZED AGENT COD NUMBER MM/____________

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Refernee all attachments here)1. Flows for April 2013 ame estimated based on July 2012 values due to totalizers being Out of Service. The totalizers ame an obsolete model and work orders ame hin place to find replacement totalizers and get them installed hin the system.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11/12012 PG-a 0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT"EE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 AI-r'I:. 7-J--.1v/=&1%1 QDPI: LTU0048313 PERmIT NUMB3ER B01-O DISCHARGE NUMBER DMR Mailing ZIP CODE-MAJOR (SUER 01) CS SIP PLANT EFFLUENT (FORMER 0018)External Outfall*"* *NO DISCHARGE E '61010 MONITORING PERIOD C MMJDONMYYYI MMIDDIYYYY FROMI 04/01/2013 ToI 04/30/2013 I I lQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF I VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX AALYSIS TYPE BOD. 5-Day SAMPLE 102 9.5 109..2 (20 Doeg. C) MEASUREMENT 26r ___ 1101___f__

0031010 Q,1 -: ____ ___Effluent Gross 'AIX,_ ______ ________pH SAMPLE 7.54 7.90 12 0 02130 GR MEASUREMENT Effluent Gross I T Q 4 Solids, totall suspended MESR NSAMPLE .r ,1.13 26 9.8 11.3 19 .24 MEASUREMENT

_____ _____ _ _ _ _ _ _ _ _Effluent Gross -WMV-0JEMI Fkrow. In conduit or thin SAPLE treatment plant MEASUREMENT 00200630 0/1 C 500601 0 m~ .. : -" .; '" ,,, , " I -- ' -" -4 i. " "- ... .. ..:. .-~ -;we Effluent Gross IMA Mt ,

SAMPLE MEASUREMENT SAMPLE MEASUREMENT CO MENTS AND EPA TIO OF AY VnerpIOaydlaTI1ONS (Rfeecew andll attachments hem re)ae ~ yTLPOEDT 1.Flw dsedthouh hi outal l e and of0 aysduing fthis kv mon mth. t ae nmyiwydtepssr tpr P. 010m,) P.e ediion may be used. 1/.,2012.PAG.'

, WhoM111119 M syte .Pets='-..

&e: .sp-"df fm am " the ;

ft -:Spi .. .064"2M13 ,-, Waraton ub ite i. to t .he b -.st .... .y bw g ,ai,. .. t ' :, :.:,:,r ac. -rteai-..--,,.nSINA I E F& ICI Plant anagerawaeMat L~EWeWliatPeatefo u)1=LI r=9 t nk"O oslqd E CU VE FIER R%TYPM n 113awd ME andUREtcMENT frWoigvlaos UHRZDAET 'o UBRMIDV COMMENT .'"D EXPLANATION OF ..NY VIOLATIONS

...e.e...c. all attacment

.......Fl.ow .-xi..te. throughi,'-,-.

thi "u l .30' of. 3.0 ."a"ys. .d--ing, this month. " , -.. .

330- (Rv0/6 rvoseiin a eue.16 1 A E1-M 0 0 0 0 z NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEIADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Wmfie Road Warrenville.

IL 60655-5701 FACILUTY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010;110048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUOR 01) CS WwTP (FORMER OD1C)External Outfall I IINODISCHARGE 61010 MONITORING PERIOD MMIDDNYYY LMDJYY FROM 04101/2013 TO 04/30/2013 I I,, I lAI I N.* Ol L.JwCI"V br0.,/ _ _FREUENCY QUANTIY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE SolidsEtotal p.nded ...... 1.4 2.4 19 0 02/30 24 sore. MEASUREMENT OO 30 0. ':o .......Effl~uent Gross r Chromium.

hexavalent SAMPLE ...... S00 (as Cr) MEASUREMENT 0103210 I+. ." ..E~ffluent Gross Chromium, total SAMPLE......(as Cr) MEASUREMENT S_01034'10 N"' : ... ++-. *-. *-4: "*.... " "" Effluent Gross. .C r, total SAMPLE ............(as Cu) MEASUREMENT 0104210 ag:- ..... .---;'. .. ...... r .. i.>..."..4.'

E~ffluent Gross r Iron. total SAMPLE ...... Soo (as Fe) MEASUREMENT 0104510 -" .'- nn:, .. '.Effluent Gross __.-_.- .., ..'. " .._-. ., Lead, total AMPLE 500 (as Pb) MEASUREMENT

'Eff luent Gross V.'t .2Q~Q~ A1Y~Nickel, total SAMPLE ............

...... .....(as Ni) MEASUREMENT

___Effluent G ro ss '4 l "". ..- ..NAMEInTLE I cer id w udraIZy of law Ut. doCmunnU and a taclum were prepard under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER cikecior supension in acrance with a SystDm dAmE to assur Ml qua persnel properly gather an evalute btlaonnmaion suaundled.

Basd an "my vpily of het person or persons Benjamin P. Youman who manag tea systo. or thoe persons drectly mWWW atfor gaow e-a n he 40intatbi., 05h3e13 intormadin is. to fie best ol my MknAeag and bellef. true. accurate, and catIpaele.

l ai GNA E OF CIPLE Plant Manager aware that te am signiftm panttiles tor ,ubrn fabs kioman. Wudt ft pmsVof EXECUTEl R AREA NUMBER MMIDD/YYYY iw -oan xU If and lapalowMA for Wwwbg violatns.

AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Raference all attachment here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow eAdstel through this outall 20 o130 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/162012 PAGE 1-0 0 0 0 z NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE: MAJOR (SUOR 01) CS 61010 IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDIYYYY I MIDDIYYYY WWWP (FORMER ODIC)Extemral Outfall* NO DISCHARGE EJ "'FROM Il 04/01/2013 TOI 04/30/2013 Il l-13 0 0 0 M 0)F 41 11 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADORESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACIUITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER D01-0 DISCHARGE NUMBER MONITORING PERIOD MM1DD/YYYY I MM/DDWYYYY RADWASTE TREATMENT (FORMER 0010)External Outfall FROMI 04101/2013 I TOI 04/3012013

!"IINO DISCHARGE ED ..-vI J MEASUREMENT egpwr~: nww uneucazp 14J1 I.....~s. ..h..1 i.daL...a&~.ba.....

I ~ y I isi~at~ I I.N*ME11nTLE PRFIcIPAL OFFICER Benjamin P. Youman I certly Under penaft d law that fis docufmlen and at atlachments were prepared under My dijaction or spemvWo In accordance with a system designed to assure Unat quafted per-amni properly gather and evakie the inonrmaion submitted.

Basedn my Inquiry a thie perso pesmons who manage the system or tlase persons drecty responsibe for gathering Me informatio.

Me Intonmata subeted is. to"e best al my knowledge and befie, rue. acmrate. and complete.

I am aware a thre are penalties far suWMig fase infomatim, te poassby at fme and mpasimment for kowing violatios.

TELEPHONE 406-3700 Plant Manager EaR -nimITl)MMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)Row existed through this outtall 12 of 30 days during the month.

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfeld Road Warrenville.

IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER OUR Mailing ZIP CODE: MAJOR (SUSH 01) CS STORMWATER (FORMER 001E)External Outfall 9

• NO DISCHARGE 61010 MONITORING PERIOD UM/DOVYVYYr MMIDDI1YYYY FROMI 04/0112013 ITO 04r30/2013 Il r lByron, IL 61010 ATTN: Zoo COXIENV SPEC ______________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER EX OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE SAMPLE ........ 00 Solids, total suspended MEASUREMENT 0053010-'z.

.0 ,. .Effluent Gross W.- Si .r SolPtotal suspended SAM28.7 57.2 19 0 01/07 GR Solids, tol suspended MEASUREMENT 00530804vIR Other Treatment.

Process %rr complete Chromium.

hexavalent SAMPLE .... .... 5I (as Cr) MEASUREMENT I 0103210 : Effluent Gross Chromium, total SAMPLE ...... 500 (as Cr) MEASUREMENT

_0103410 Ys t Copper, total SAMPLE ...... S..(as Cu) MEASUREMENT 0104210 tw5MKt ,. r -- -.~4 4 -V: Iron, total SAMPLE ...... .. ...... ....5 (as Fe) MEASUREMENT 0104510 v PTj .... .. ... : "M...,___...

Effluent Gross _OEM ~l~r ~~t.--Lead, total SAMPLE .. *...(as Pb) MEASUREMENT 0105110 ~' .~pr s ~ .~ :'-- >pU Effluent Gross '.. ..119 "*1/4 ." 'I ' " ' ". -: >- " -- NAME/TnlE I ceiy under penafy o law t n is document and a all nuemns were parMed under my TELEPHONE DATE PRINCIPAL EXECUWnE OFIRCER direction or supervbso in accordae with a system designed to assure th qua pervannelgather and evakite the information submitted Based an my inquiry of te person or person A..' 815 406-3700 Benjamin P. Youman who manage the systmn. or tose persons Wocty reponsbe gathra g t inoametion the 00232013 ilotnisbon submitead is. to the boe d my knowledge and b--al. tnre. awcuate, and complete.

I am NAVE-X OF C 05/C2 1 Plant Manager aware that there am signifcant penaflis for sabmliting lase informatimn.

Inciuing the possalldy EXECUTIV NUMBER MM/DDYYY on a1 ine and nimpuontnent 1 knowing violatons.

AUTHORIZE AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference ail attachments hem)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow eidsted through Oth outfal 15 of 30 days during the month.3. Are Proection drain water was discharged this month EPA Foem 3320-1 (Rev 01106) Previous editions may be used. 1/6/2012 PAGE 1I* 0 0 NATIONAL POLLUTANT DISCIGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)0 PERMfTTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY J I MMIDDJYYYY STORMWATER (FORMER 001E)External Outfail* *NO DISCHARGE

• 0 FROMI 04/01/2013 ITO I 04/30/2013 Byron. IL 61010 ATTN: Zoo CoxIENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF YP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Nickel. total SAMPLE Soo.. ...(as Ni) MEASUREMENT 010671 0

.E~ffluent Gross AR ~2 Zinc. total SAMPLE 500 (as Zn) MEASUREMENT 0109210 R.,+ ... ' -. :. '.1+ .. +. ' '+ """ " '"" Flow, In conduit or thru SAMPLE 0.564 1.701 3 0 02130 .CN treatment plant MEASUREMENT SAMPLE MEASUREMENT

+,~A .., ., --v.SAMPLE MEASUdJREME-NT

__ _ __-__ _ _ N -I -1£.. -"+.. ..-. :+. : ...MEASUREMENT

-__ _.-.__ _. :.'.+ .. .. j.~~~~4 -4t**~t~,~KiE/IT.E I cattify under penalty d law dhu tihs documemt and al anuadeuntas were prepared und my TELEPHONE DATE PRINCIPAL EXECUTIVE OFPCER Wiean or supev i with a system desiged to assur thd qualifed Wenel Spmperly gather and evatlla the Ionsoatm submitted Based mo my nquty of the pesmu of persons Benjamin P. Youman who manage the system. or atse pers" directly mspmnsbe tor gathme"Og the malman. fte T F"13 inforritim submntd is to the besto my WwWedge and betef, true. acoirata end =pMits. Iam SIGNA1UAR OF PNUMBER Plant Manager aware hat tere are Winfant penalties for sunTdi9 false ingla o ,mato. i 0 ft ia of EXECUTIVE OFFtheR OR MAREA/YYY f nIne and Wlriint for Mknw vdalaons.

AUTHORIZED AGENT CODE MMIDDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Raefernce all attachments hem)1. No Closed Cooling System Drain Water was discharged this month.2. Service Water System drain water was discharged this month.3. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Cleaning wastewater was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612012 PAGE 2 0U 0 C: 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEJADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACIL1TY Byron Nuclear Power Station LOCATION 4450 North German Church Road i I.0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER DER Malfing ZIP CODE: 61010 MAJOR (SUDR 01) CS COOUNG SYSTEM BLOWDOWN External Outfall I* NO DISCHARGE EJ E MONITORING PERIOD MMIDD/YYYY I MMIDDJYYYY FROM I 04101/2013 ITOI 04130/2013 I I I Byron, IL 61010 ATTN: Zoe CoxIENV SPEC ______________

___________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER

_________________N.

OF SAMPL.E VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX TYPE[>< IANALYSIS Temperature, water dog. SAMPLE ............

.............

82.8 15 0 01/01 CN Fahrenheit MEAURMENT pH MPLE ...... 8.48 8.70 12 0 01/07 A GR MEASUREMENT 0040010 7. -7 7 Solids, lotaluspended S 10.9 11.1 19 0 01/30 GR Solds toalsusened MEASUREMENT Oil & Grease SAMPLE .4 <1.4 19 0 01/07 GR MEASUREMENT EffluentGross

-. " Co , total (as C)... ... 0.011 19 0 01/07 GR MEASUREMENT ZCo ta (aC SAMPLE .. 00 0.02B 19 0 01/07 GR MEASUREMENT Zinc. total (as Zn) SAMPLE ....... 0.1 .06i,.0/7G 0109210 4 k 15A Effluent Gross Elk "... .9 0 0 N*MEMTITLE I cany under Iwpenayf law that this document and a attachienrt wers purpanted y TELEPHONE DATE PRINCILPAL EX-CUTIVE OFFICER dWCOM W Supem,,= in accordace with a system desgn1ed to astsri that qualed personnel pmpety Sgathae end evaritU ntiormaton.

submted. Basecd n my nui b e d the person ma peons8 Benjamin P. Youman who manage the system, or throe persaons dimcy rsmsponsM for arhemO e ing die ----- 4-FPR I7 05/23d2013 inoimation sularnited

a. to the best d my knowledge and beief, true. acrte, and ca*myete.

I am SIGNAnlJ OF P PLE Plant Manager aware diat there am sil'rat pename for submitlbn false Infonnb. bidzdng the posaiksty d EXECUTIVE OFFICER OR AREA UMB ibis and imprislomt for knowug viclalba.

Cuoz AGN No ER _______________

TvOPOCI I iead I AUTHORIZED AGENT COENME0M/DrY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. Monftonng data for outfall 001-0 is included on attachment.

EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/0/2012 PAGE 1 0 ,'a 0 0 C 0 o NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exulon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCA1ON 4450 North Genman Church Road Byron, IL 61010 A1r'r'J- 7 PrimfJ-UA~l QOD::'DMR Mailing ZIP CODE: MAJOR (SUOR 01) CS 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD I MMIDDWYYYY I........ !ITol I MM/DD/YYYY I COOLING SYSTEM SLOWDOWN External Outfall**'NO DISCHARGE " I lFROM i 04/01/2013 II 04130)2013 I I I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE ARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TAMPLE E5 ANALYSIS , ___Oxidants, total residual AMPLE ............

0.04 19 0 01/07 GR MEASUREMENT 34044108AMPL

.. 50'Priority pollutants total effluent MEASUREMENT 500081 0 -oIn..:- .Effluent Gross _ ... ,..Flow, In conduit or thru SAMPLE treatment plant MEASUREMENT 50050 10 ~- *Effluent Gross = -T .4 m.Chlorine, total residual SAMPLE .....500 MEASUREMENT Effluent Gross -W AS ;Hydrazine SAMPL..E SI........0 MEASUREMENT50 Effluent Gross O1 , QT MEASUREMENT MEASUREMENTLE I certia nder penaly 01 law 0a this er and afl anadmunas wet preparetd wider my NONE PRINCIPAL.

EXECUIWU OFFICER tlrectimi at aupevislo in accotdance with_____a__

_ sstem desined to asasur that waffed persamat 1 ,.,J LE H DATE Bejmi P roperly gather and evahfla tea Infomavaon submaled.

Based atmy avy Wqf of the person at persons -V/da miP.Yw na the syte t persons dreofty resportsm for gaftfl t SI F P _______815 406_3700________

Plant Manager kdinfor n eutmued AI. to the eao of my knowlmedge and bee. rem. and omlplu ar i am SI--= ---F P'iP--lwarM that thge amo srulkant peae t subonittnri false inlonnadi.

includitg me posemay of EXIE E OFFICER OR AR NUMBER MM/DO/YYYY

__ _ _m _ _ ,.e aON hnrnfninlm.n.t for knowing violaions AUTHORIZED AGENT COD N COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Raference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2"D 0 0 0 03 X NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvide.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4460 North German Church Road DMR MailIng ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 F DISCHARGE NUMBER MONITORING PERIOD MM/DDN/YYY I I MM/DD/YYYY STORMWATER RUNOFF BASIN External Outfall* *" NO DISCHARGE"7

...FROM 1 04/01/2013 I TOI 04/30/2013 Byron, IL 61010 ATTN: Zoo Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER EOF TAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS Solids. Total Suspended MEASUREMENT

.... -- -.00530 10 ." ",." Effluent Grossw~' 4 i 61 i ,,f Solids, TotalSuspended SAM 197 198 19 2 01/07 GR Solds ToalSusened MEASUREMENT 0053080 " " W 4 : .** .' .' .: ..." "" " " " Other Teatmnent, Process .-Chromium, hexavatent SAMPLE ...... ........0 (as Cr) MEASUREMENT 0.1021"0 ....... ..' " ' .... ....:,01. .. -" ., ""..Effluent Gross NO N -Chromium, total SAMPLE Soo........(as Cr) MEASUREMENT 010341 0 .Effluent Gross 2I., .Copper, total SAMPLE ... 500 (as Cu) MEASUREMENT

..... .- .. ..... .., " Iran .total SAMIPLIE 500......

.(as Fe) MEASUREMENT

.. 0 0104810 Zm-.ff.IT:zu

,... ;Lead, total SAMPLE ..... ...... ....500 (as Pb) MEASUREMENT 500 0105110 8 W~_ _ __NAMEIT'LE I canldy under penarly of law thai this document and ats allchments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFRCER direclon or supensisa in accordance with a sytem designed to assure thao qualifed pearsaiel pedy gather and evatfe the ibonnation subnaed. Based on my ht of the pmon of peoons 15 03700 Benjamin P. Youan who manage the systen. o those persons diredtly esponsbe for gathering the Iomadon. theg 05232013 Dormal s P Is. to the bow d my knowegede and bdel. tMe, accurate, and comp"e lam SIGNATUV E OF P7062C0PLE Plant Manager aware that here ae signficant penalties for sulang Idee idonnaton.

Includg the possaft EXECUTIVE ER OR AREA lrmE o a sxn m FIN__Onn and __ _ _ _ _ _ _ _ _ _ for __Wahl% vi__ms. AUTHORIZED AGENT CO NUM BER M M IDD YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Ol Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. Fire Protection and Service Water System Drain Water was discharged this month.3. No Closed Cootinq System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 1 0 0 0 0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMI'TEE NAMEIADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warmnvlte.

u 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron,IL 61010 DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 I _DISCHARGE NUMBER MONITORING PERIOD MMIDDIYYYY I MMIDDIYYYY STORKWATER RUNOFF BASIN External Outdall*NODISCHARGE FROM I 04/01/2013 I TO I 04130/2013 l i QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Nickel, total SAMPLE 500 (as Ni) MEASUREMENT 0106710 ASR I~ ~v*T Effluent Gross I"- ...;'Zinc. total SAMPLE .......(as Zn) MEASUREMENT Effluent Gross" ". A.. ..: ..-, ..O and Grease SAMPLE ..........

... 4.9 2.3 19 0 DL/DS GR MEASUREMENT Effluent Gross' .... " f' ..Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT Effuent Gross ýMwm

..::.:, +SAMPLE MEASUREMENT

.4..^ "-,.- > + .+ .,. ,,, + ...-..3 4 12.44, .1.....

~ ~ ...... ; ... ....SAMIPLE MEASUREMENT , i NMFITr I cetity under penatk d law thathis doment and al allaezenl were prepared Undler my TELEPHONE DATE PRINCIPAL EMCUMV OFFR *lcton of spervsion in a wah system designed to assure that quatfWied personner prope gather and evwke thetIdormatin subttentsd.l BasndIN thperP- , O-M15 40-3a7 Benjamin P. Youran who manage the system. or those persons directly esponsble for gathier the fte ,13 ionmatim vulnduea is. to the botw o my knowld and betef. tree. a=ret. and *OMpete. I am SiGNA1Uo OF P 051J3/....

Plant Manager aware dhat there are srgni-at tor somating false odoi hindul lte ft hd EXECUtjE OFFICER OR NMEAmManager ine and rnprslonment for Iknowing vkAUaOZDs.

GTE NUMBER M/D/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 2 of 30 days during the month.2. There was no discharge of processed steam generator chemical cleaning wastewater during the month.3. Upset defense used lor TSS concentration exceeding limits. See DMR cover sheet for additional details.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 2-0 0 0 0 0 G)

ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 April 2013 Page 1 of 2 MONITORING DATA: WBD CRock River DATE Temperature mgd Flow deg F cfs 04/01/2013 74.1 14.27 12,800 04/02/2013 78.2 21.11 12,900 04/03/2013 78.2 17.82 12,900 04/04/2013 82.7 18.58 13,000 04/05/2013 82.7 20.82 12,900 04/06/2013 82.6 24.65 12,900 04/07/2013 82.8 15.29 12,700 04/08/2013 73.7 14.96 12,500 04/09/2013 73.3 19.13 12,900 04/10/2013 70.4 18.74 14,900 04/11/2013 68.4 20.40 17,600 04/12/2013 67.2 22.95 19,800 04/13/2013 59.8 20.09 20,200 04/14/2013 72.6 24.15 19,900 04/15/2013 72.6 11.69 20,000 04/16/2013 68.5 11.35 19,900 04/17/2013 62.4 10.82 21,000 04/18/2013 70.0 11.90 31,800 04/19/2013 70.0 14.63 39,000 04/20/2013 59.7 13.53 39,800 04/21/2013 63.8 13.10 36,800 04/22/2013 68.7 11.87 33,200 04/23/2013 73.9 12.36 30,600 04/24/2013 67.3 13.45 28,400 04/25/2013 67.3 11.94 26,500 04/26/2013 68.1 13.48 24,700 04/27/2013 70.2 13.40 23,100 04/28/2013 70.2 10.63 21,800 04/29/2013 73.6 11.63 20,700 04/30/2013 81.1 14.43 19,500 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2013\April\April 2013 ATTACH01.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 April 2013 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of April 2013.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 30 of 30 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 38.1 mg/L on 04/08/2013.

The CWBD TSS value was 11.1 mg/L on 04/08/2013.

5. Rock River flow for April 2013 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in April 2013. (Special Condition 15).K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2013\April\April 2013 ATTACHO1.doc Exelon Generation Company, LLC www.exeloncorp.com Byron Station 4450 North German Church Road Byron, IL 61010-9794 June 21,2013 LTR: BYRON 2013-0082 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number IL0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of May 1, 2013 through May 31, 2013.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Benja~ea Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments bcc: Kevin Hersey -Sr. Environmental Specialist

-Cantera (electronic)

Zoe Cox -Environmental/Radwaste Supervisor

-Byron POOR QUALITY ORIGINAL NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIrTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road WarrenvWlle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUOR 01) CS 61010 I IL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY I MMWDDWYYYY DEMINERAUIZER REGENERATE WASTE (001 A)External Outfall I *" NO DISCHARGE

-*FROMI 05/01/2013 I TOI 05/31/2013 I Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANITIY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids, Total Suspended SAMPLE 1.6 2.1 19 0 01o30 08 MEASUREMENT 0053010 P"PR.IT -15 30 Effluent Gross -REQUIREMENT

."-" ...__ -30DAAVG DAILY MX M,. C P, Chromium.

hexavalent SAMPLE Soo ""." ..-5 (as Cr) MEASUREMENT 0103210 ' :GRERRAT ...1,, Efuent Gross REQUIR'EMENT

...._. :_ G PAJL .... .-, ...D. GRA Chromium, total SAMPLE S....... ... 5o (as Cr) MEASUREMENT 01o3410 .2. .. ' , ... .... GRA Effluent Gros sE.UIRE- " SODA AVG DAILY ..ma., Da"Oy GRAB Copper. total SAMPLE ...... Soo (as Cu) MEASUREMENT 0104210 .e.. PW.. z ...s ..mL -aly GRAB Effluent Gross .'-RE , _R.. , SODA AVG DAILY MX -Iron, total SAMPLE .500 (as Fo) MEASUREMENT

_010451 0 POW DORY 1 Effluent Gross R ,MEM , , , DALY MX Lead, Total SAMPLE S...o ,. ......(as Pb) MEASUREMENT 01051 10 ;.E rr ~.. ..', ,., " .,, ".- , "." ." .4 7 ." al 0105110' ..................

_ SODAAVG.I

• DAILYMX. 2".. -':'Daily GRAB Effluent Gross REQUIREMENT L30DA "V: ,I MX, Nickel, total SAMPLE Soo ....... 500 (as NI) MEASUREMENT 0106710 PERMIT -,,,e. -.e i .e,.. !e 'Effluent Gross REQUIREMENT .PDAAVG. ODAYMX ...... GRAB NAME.,TlLE I certify wue penaly of law OhW Vi documem and W we prepared -nder my TELEPHONE DATE PRIINPAL EXECUTIVE OWFCER O:don in scoode arm a a'sstem damged to aure Vil wquLaffed peaona 1 vopedy garn erw eneaP Me ftodrrndan wdx~nfta.

8ased an myr kqukv d the P~ron= Of P -,1 46370 Benjamin P. Youman v" nmpW the syn or th-se pene dircty eoside 1w gada f I'me0 ft _815 406-370W 06/21P2013 lienwan m&WMW i. to to bw of my wwwww wn l@W, Mo. acuae and conle.I am SIG V-RE O&INCIPLE Plant Manager awam Via these are titntfim penarles for umalnlrt false bte pua at o E XUTIVE OFFICER OR AR NUMBER MDD/YYYYpfswm _i;W wpbiwm for lbwo alorm. AUTHORIZED AGENT CODE NUMBE _ _________COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow e)dsted 31 of 31 days during this month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/6/2012 PAGE 1 POOR QUALITY ORIGINAL NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 610107nn (-.jwdI=NV RPI:=t'OUR Mailing ZiP CODE: MAJOR (SUBR 01) CS 61010 I IL0048313 PERMIT NUMBER A011-0 DISCHARGE NUMBER MONITORING PERIOD ,M/OD1YVY

___ I MMIDDIYYYY DEMINERALIZER REGENERATE WASTE (001A)External Outlall* ** NODISCHARGE

-FROMI 05/01/2013 1TOI i-05131/2013 I q I A TQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TAMPLE Lý<ANALYSIS TP Zinc. Total SAMPLE .500 (as Zn) MEASUREMENT Effluent Gross -INEQREMENT:

",_,"___ ;' -"..__" : 30DA VG DAILY MX"G Flow, In conduit or thru SAMPLE treaiment plant MEASUREMENT 50050*10 ". moD AVG0 DALY -. : V".. Daily CONTIN Effluent Gross REQUIREMENT

_.-30DAAVG_

DALY UK_,_ ' " _ _ _ ________SAMPLE MEASUREMENT REQUIREMENT

-SAMPLE MEASUREMENT

........ "___ ____ ___ ___ __SAMPLE MEASUREMENT

• PERMIT REQUIREMENT

_____ _____ _____ __________

SAMPLE MEASUREMENT

• _ __ _REQUIREMENT

_SAMPLE MEASUREMENT

• PERMIT REQUIREMENT-__________

_____ ____ ___KAKEPITLE I cltify was petafty law diat oft domarmmd and all elaclwrita wereS prepared wider my TLPOEDT PRIlINPALECUIVE OFFICER Oadooraeimin 4~ scwac wftm a systm dosigia to ast V tad Wd p TLEHOE AT Wampafty gather anid evahite ft e Wmmatia submitted.

Based onmy bftiar of thie perso or per~s 11 0630 Benjamin P. Youmnan who manage the sysfem or ftose persona dradly reapwonbie tor gafheutn do tntonarsimwr AA e 06121/213:il -miation aidrtted W to fte be of my otedge '.- be"d. rm. ,ac "ate. and c Ie .am FG "E OF P IPLE " ' ::'Plant Manager EE EO tEROR ARENUMAER "M"D" " COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flows for May 2013 are estimated based on July 2012 values due to totalizers being Out at Service. The totalizers are an obsolete model and work orders are in place to find replacement totalizers and got them Installed in the system.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11111=112 PAGE 2 0 0 0 POOR QUALITY ORIGINAL PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Waffenvllle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 Ar... n~~ne^r NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)DMR Mailing ZIP CODE: MAJOR 61010 IL0048313 PERMIT NUMBER 5B51-O DISCHARGE NUMBER (SUBR 01)CS MONITORING PERIOD[__ MMIDDWYYYY L_ u/DDJvYYYV STP PLANT EFFLUENT (FORMER 0015)External Outfall I I*NODISCHARGE FROMI 05/01/2013 TO 05/31/2013 I I m QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FEQUENCY SAMPLE PARAMETER

__F__TYPE_

VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX AFY TYPE SOD. 5-Day SAMPLE SOD, 5.CayMEAME 0.49 0.53 26 12.5 16.0 19 0 02/30 24 (20 Deg. C) MEASUREMENT 003101 0 ,PEMT .. ..,- 10.5 3 60 Effluent Gross ..RRQUIREMET M G DAILY MX _._-, :, 30DA AVG" -DAILYMX n: .. TwIce.PerMonthCOMP24 SAMPLE ... .7.53 7.80 12 0 02M30 GR pH MEASUREMENT oo~~~~oo~

....r ........_...G.Effluent Gross -REQUIREMEM "T .."":- ________.

...... :.".. MINIMUM 6 !. .". .. " ' I- .A)CJlJM : __P, _ M____h Solids,total suspended SAMPLE 0.15 0.18 26 -2.8 3.6 19 0 02/30 24 MEASUREMENT

__________________

____0053010 MST3 10.6 30 60_Effluent Gross REQUIREMENT

".,300A` AVG, DAILYMX _,_... .,,30:AAV.ALX":

TwIce r .Month C P2 Flow. In conduit or thru SAMPLE treatment plant MEASUREMENT 0.006 0.011 3 0 01/01 CN 5005010 o..ERMI RfTMO.. Re ._.. -, .Effluent Gross REQUIREMENT-S30DA AVG -DAILY MX .* Daily CONTIN SAMPLE MEASUREMENT

_______________REQUIREMENT________________

SAMPLE MEASUREMENT

_____________

P"qMrr.-REQUIREMENT

...... ......_______ __ ___SAMPLE MEASUREMENT

=_REQUIREMENT NAME/Tn.TE I certy under penally oa law doat th document and alU hmenD wr prpard under my TELEPHONE DATE PRINCIPAL EXECUA lVE OFFICER d of v Wm in e whh -ey~en *l i to assure O W q led pemTrEnel Benjamidn P. Youra proerl gather1 Nd evlt the Inonelr satre aa niyb fd esno esn 815 T406-3700 0/121 BjrnP.Yumnan wto menage the or uft persons drecy iesponsite for 0&mer, dwth kdommilr to 06/21/2013 knnodon s&bWwW Is. to OF boo o my laowiedge " bete. trueP acust. anoste. ILEm _ _ OF Plant Manager awarm that tSU U patltes amtn*h false biloaln, hckftG the b F CER OR AR'EAo NUMBER MM/DD/YYYY TOW ON I and knPalionnt for bwnoag vitorm AUTHORIZED AGENT CODEJ COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 27 of 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE1" POOR QUALITY ORIGINAL NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DUR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN* ona t"=nxIFlNV RPI:f DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDYYYY I MMIDDYYY WWTP (FORMER 001C)External Outfall* *

• NO DISCHARGE FROMI 05/01/2013 ITOI 05/31/2013 I PARAM..ER QUANITrY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNEIT OF TYPE....IT ANALYSIS Solids. total suspended SA-PLE8.2 12,4 19 0 02/30 24 Solds toalsusened MEASUREMENT 00530 10 "MIT 1 -. 30 Effluent Gross ,REQUIREMENT

-,, .," ..30,DAAVG

.-DAILYMX JTc,'PerMonth COMP24 Chromium, hexavalent SAMPLE 500 (as Cr) MEASUREMENT_500 0103210 PERMIT Daily GRAS Effluent Gross ;00E#QUIREMENT

_ " 3-.A DAILY M).(Chromium, total SAMPLE ..--- -.(as Cr) MEASUREMENT 500 0103410 PIRml,. * :- "A*Effluent Gross -' '- ." ._ _ _ D A D " y Copper, total SAM PLE .. ... ..(as Cu) MEASUREMENT 500 0104210 -...; ":" -' -: .3DAG5 -- 1AL X gL ..""Diy GA Effuent Gross RIEQUIREMENT

.., "" "" .-. ...(asflent Gross 300__ __ _ _ _ __ _ _ OA AVG DAILY MXC m g/. Daily GRAS Iron. total SAMPLE -p (as F e) M E A SU R EM EN T 500__010451 0 0ERMIT , Effluent Gross REQUIREME.T

,_ .. L ...G Lead, total SAMPLE DAIL ....(as Pb) MEASUREMENT 500 0105110 1PERMFF11 SIXA F eENue.t.Gross"REQUIREMENT

.4-* __, DAILY MX .,.. .._.., GRA Nickel, total SAMPLE ..(as Ni) MEASUREMENT 500 0106710 500:" --".. 2 G S URE.-A DAILY MX -GRAS NALECTIVE ceRrty under penaty at law Mi fot cocunemwd and ,. aftachdenta were Prepared unde; my tELEPHONE DATE PRNCPA EEO~hE F~CuR~reacdn or aajpwvwn in a mdencer vm a aYWtni daalgnad to mague gola mflie F.e-raTLEPONEDAT Benamn .ouna rpeilgaflixer a udmaaVe bilonnab ahltd. Asadon ny fmiy of Ve pumaonopemom 815 408-3700 0/121 Benjamin P. Youran who -rga fte y-am, or Vim pnmm dWlreofy eponWtns for galheb the V.dolmaVn.

Vie 21/0'rtf n nailon Ited b ,to ft beae ofmy knowki d and b*ef. true. a nu as. and m qoet. jam -4W7RE000CIPLE P la n t M a n a g e r a w a re t h a mere a re dl nmcarV p e n a, le fo r s u ba t ln g as e kf o mi" a tb i k nc g n 0 # W p o e saw y o l E X E C U T IV E O F R IC E R O R 0N BM 1 / Y0 1 Y flPWMPROUMelE fo an I5nOv*A- tor www~dei elaldwa.m____________,_________________________________

~r=.AUTHORIZED AGENT CODl NUMBER ____ ___ ___ ___ __COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments tere)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outfall 14 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1162012 PAGE 1

.POOR QUALITY ORIGINAL PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Waxrenvije, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 A3"rl- 7,u ('V/w~IUNI OIO::t NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)I IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER DMR Mailing 33P CODE: MAJOR (SUBR 01) CS WWTP (FORMER ODIC)External Outfall***NO DISCHARGE r " 61010 MONITORING PERIOD E MMIDDN1YYY

• _ MMIDDNYYYY FROMI 05/01/2013 I TOI 05131/2013 Il ll I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE* PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TYPE Zinc, total SAMPLE ., (as Zn) MEASUREMENT 0109210 P NI4IT'. -" --,, ..:.-T " ." 1- 2-- .. ,,_ G Effluent Gross REQUIREMENT xu AVG DALY Di -GRAB I Flow. in conduit or thru SAMPLE tramn ln.MAIEET 0.022 0.037 3 .... 0 01/01 CN treatment plant. MEASUREMENT

______________

50050 10 PMW lq o, N.0o ue Gro0s *:: PERMIT.'" Req. Mon... .,ReOI. ",. ..',,m "Daily CONTIN Effluent Gross REQUIREMENT.

30DA AVG DAILY MX .. .... ."* .." SAMPLE MEASUREMENT

..:PERMIT.: REQUIREM "NT -..... ...SAMPLE MEASUREMENT PERMIT

.____ _SAMPLE MEASUREMENT P9RMlIT_______________REQUIREMEN

_______________________

_____ _________SAMPLE MEASUREMENT-PERMIT' .__REQUIREMENTr " .:. _ .... _.:_"_"_"_"_'""" SAMPLE MEASUREMENT

_.REQUIREMENT.

.., ._ _ _ __-_.,_,_.

NAEXTIVnE fI *artiy under inalty o law Vat me document and d, aftadunuft w pxapad under my TELEPHONE DATE PRKWAL EXECUmleVE OFFR corMcsdn ooi accolnce th a systenm designwd to that qiad personne prcp gathr and e~lue the kInormation eubaufed.

Based an my bwpfti of me* person or persons Benjamin P. Youman Vo rmanage "a sysm. of ft" persons drecdy esaporute tot me Intannallon.

me 06421/2013 kItomtallo eutmiftted W. to meo best of my Noleeedge anid Meel. tnae. a~rrmw ant comlee. lam SIGNORE OF CPC Plant Manager a~ware ft~ro ame 90fl-M penW for aftntklin fB~w kdonnedon, blk~dbV the poess:)y of EXII&UTIVE OFRCER OR AREA a-- Mae I , n m lt AUTHORIZED AGENT iCODdNUMBER MMIDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 146=212 PAGE 21 POOR QUALITY ORIGINAL NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfleld Road Warrenville, IL 60558-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTM- DMR Mailing P CODE: MAJOR (USBR 01) CS 61010 IL0048313 PERMIT NUMBER I01-0 DISCHARGE NUMBER I I MONITORING PERIOD RADWASTE TREATMENT (FORMER 001 D)Extenrai Outfall FROMJ MMIDOIY I I UMIODNIYVY 05101/2013 I ToI 05131/2013 I* N ISHREJ .I *ARAMETER QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX O TYPE 1 <IANALYSIS Solids, total suspended 9.3 18.0 19 0 02/30 CP Solds toalsusened MEASUREMENT 0053010 -"M.7..0:--

T P "Mo -MPS Effluent Gross REQUIREMENT A _ ...._"OAAVG AMP Flow. In conduit or thiu SAMPLE -0 treamen65 0.048 3 " "* 0 01101 CN treatment plant MEASUREMENT 5006010 o ! ...Req.. ... -*~~ ~ ~~~ ..... -4.4..1.4

CONTIN Effluent Gross REOUIRWENT S-

O)DA AVG DAILY MX 7.. ..... .NN SAMPLE MEASUREMENT PERIIT______________RE0JIREMIENT .cj::>-..SAMPLE MEASUREMENT

___ _____________

____ ___,PRM ... ... ....SAMPLE MEASUREMENT PERMIT_REQUIREMENT

." .-. .. .- " SAMPLE MEASUREMENT

PERI T .: ...,... .--_______________REQUIREMENT

.. -SAMPLE MEASUREMENT-REQUIREMENT

.-. ._ _,_. ." " -' ' ..', -.NAMEITIME I cemy undr U P1ay of WI 11 11* docUm and ad nerchmwft

-Prefd vaide my J TELEPHONE DATE PAINCWAL EXECIIUhI OFFICER d con orjj 0, per~sim In a~m rdicu w4it a *W orn danigna to masue M qmat ai ed Parsonno J -I pnopady gnawe en evahti f bUfrn nosmatn sutinftta Based an myr Mhiqiy of the permon of penwoin85

-30W123 Benjamin P. Youman who mrnag the Uyrernu or Urtem pos dndy raspwanbe r geIhe tihe Irdworelbm o 06/21/2013 wwnftomnib euteriuwites.

to ftn bean of nV bwewadg andt betel tmu, accrate, and 0Wsrqe*Wt&

I. am___ _____________RE_

Plant Manager awawe & mtathere tnd pefnae for Siflt lain kdonrafm kWiie E)JyCU1T OFRCER OR AR ND Sim o R p m f ._i _ _an d _ _ _ _ _ _ _ _ _ _ _ _ __Nf_ _v"_l__ A U T H O R IZ E D A G E N T C O D N U M B E R I_ MMD DY Y Y Y COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 6 o131 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/1/2012 PAGE 1 0 POOR QUALITY ORIGINAL PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road WarrenvilWe.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 NATIONAL POLLUTANT DISRGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER-MONITORING PERIOD MMIDDIYYYY MMIDDJYYYY STORMWATER (FORMER 001E)External Outfal* **NO DISCHARGE -J FROMI 05/01/2013 ITOI 05/31/2013 I I e ATTN: Zoo Cox/ENV SPEC I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO.' FREQUENCY SAMPLE PARAMETER EX OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Solids, total suspended MEASUREMENT 00530 10 PERMIT .-.... s15 30GRAB Effluent Gross -REQUIREMENT 300AAVG DAILY MX* .So.toa ssene AMPLE ....o-5o Solids, total suspended MEASUREMENT 0053080+ l

• i. " " ' 30 '100 Other Treatment.

Process -t PERIT -.... GRAB Complete " wi .. AVG. D,,L. .G Chromium, hexavalent SAMPLE 500..(as Cr) MEASUREMENT 0103210 , MI .- -- ,OAAVG MX "taJL Daily GRAB Effluent Gross .REQUIREfE, -. .. .'", .-.Chromium, total SAMPLE 0 .....(as Cr) MEASUREMENT 01034 10 P9RMIT .... 1 2OW Effluent Gross RM -- DA AVG DAILY I4X , mOIL Daily GRAB Copper. total SAMPLE .....(as Cu) MEASUREMENT 01042 10 .. PERMIT ..., ., .5 1 Effluent Gross REQUIRBIENT

,_-__ _____, __

• DAV DAILY MX GRAB Iron, total SAMPLE 500.. ......5 (as Fe) MEASUREMENT 0104510 PERMIT: ...... ..1 Effluent G ross R EQ UIR EM EN T7 ' _ " _." '_ .. ._ __. .....". ", DAILY M X angIl "all/ G RAB Lead, total SAMPLE ..... .500 (as Pb) MEASUREMENT 0105110 PERMIT ... .2 .4 Effluent Gross REQUIREM"NT.

30DA AVG .'DAILYMX (i Daily'. GRAB NAMElMTLE I cedit urune penafty of ku Ow Oft documen al a-"acih.les m puivad urdMr my TELEPHONE DATE PRINCIAL.

EXECUTIVE OFFICER cszuctimtor apez~ton iaccoranc

,1a ftoavu 'iag~t inxs w toswiaiqimi.

P-0Mo! DT papesygamm and evaluta the kdomviilon mmfed. omnm o mynquy of the ped orpwwm 815 406-3700 Benjamin P. Youman va, manage tue fystwm, or tmose perm dhreey rasponulble tfo gathmng the bdofmZn 112013 titommaton smintt is. o to ft b my aW e aind belef, tm. agmeu.ue and I arn SI=GN RE RINCIE Plant Manager awm thl fte ase aditca penalles tIa tab. Istont , la kditof ft a EARRO NUMBER MMoDCEYYYY

o. ai I O Eaifo AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemlcal cleaning wastewater during the month.2. Flow existed through this outfall 5 of 31 days during the month.1. Therm was no discharge of Fre Protection drain water during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612012 PAGE 1I POOR QUALITY ORIGINAL NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvile.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 I IL0048313 I PERMIT NUMBER E01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDIYYYY I I MYDWYYY DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER (FORMER 001E)External Outfall***NODISCHARGE 61010 FROM II 05/01/2013 I TOl I 05&31/2013_

I I OUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREOUEUPY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel, total SAMPLE ..(as NI) MEASUREMENT Soo 0106710 PRM -1 2..Effluent Gross REDUVREMENTG.'

DLY MX ' -"..pa ly G*Zinc, total SAMPLE * -.***** -- 50 (as Zn) MEASUREMENT

__0109210 ...... .... -I 2 Effluent Gross REQUIREMENT

--., _.'______

-,. __ j00AV.' DAILY MX .__.____Flow. In conduit or thau SAMPLE .3.D4 3 --0 02/30RAB tetetpat0.103 0.243 3... ""* 0 02'0C treatment plant MEASUREMENT 50050 10 Refl I .:R h ;N. 0 0230..Req.

M n.Effluent Gross REQURReq. ,V .AILYMX M. , ..Twice Per Month CONTIN SAMPLE MEASUREMENT PERMIT. --I.. .REQUIREMENT

"_ ' " ,,_"_" _ " '_ " " _ _ "_ ' __"_"_"_" SAMPLE MEASUREMENT PERMIT'REQUIREMENT SAMPLE MEASUREMENT PERMIT .REQUIREMENT

' '_. --_.. ._ _,_"._, _ ..SAMPLE MEASUREMENT

.__ _ _ _ _ _ _ _ REQUIREMENT

_______: _ ......,_._" .__ _ _ __ _ _ "_...:.__.___

NAM~~tITLE E I cetlty uider peflefy at low dW W t e doomnenarid end a efleceents wr rprdwdrm PRINCPAL EXECUTIVE OFR irecriori or aup@M*jon In a mdtirx whh a 6 we r prpae unde TEEaNEDT Ye eindt su 0qabdprewm TELEPHONE DATE BnadnP om pn*ropry 0ailer arid evaltre die. Wroaelri adnild Base On my biqudry dl the pinion or prw Benjamin P. Youman ahoe mOeleys. o- pe-ons drectly MsWpolble f, gaheMai* kft 8151on406lu 062/2 Pln angr ildomuar 8Avftarld Wa to the beat of my bwowledgenard beblef tnre. accndei. erid =ronuete.

aern 1/2013__ _ __ _ __ _ __ _ _Plant Manager aware fe met e ala p e for abmg lafe uornation, r Ut p y of EXEiTIVE CER OR ARpmoz NUMBER MMfDD/YYYY T ,orftrFW fine and qpdsioloment jar keou vlofallOnR.

A H Z D G TD COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference aU attachments here)1. No Closed Cooling System Drain Water was discharged this month.2. No Servico Water System drain water was discharged this month.3. No Turbine Building Fire and Oil Sump or Generic Non-Chem"cal Cleaning wastewater was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2

• POOR QUALITY ORIGINAL PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvlle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY I I MMIDDJYYYY 0MR MaUlng ZIP CODE: 61010 MAJOR (SUBR 01) CS COOLING SYSTEM SLOWDOWN Extenal Outfall NODISCHARGE EZI I.FROM I 05/01/2013 ITol--I 0&31/2013 I a -Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS Temperature.

water deg. SAMPLE ,- -,88.3 15 0 01/01 CN Fahrenheit MWA5LRgEMEMT-miii, " " "iTR q. Mon 1::.

O~I 0 0 01 1 1 0 o p ally.C O. ,N. : ..T. ...Effluent Gross IMEATUIREME.T

..-*,Rq. -q .aly;CO-TIN pH SAMPLE --- 8.42 8.59 12 0 01/07 GR MEASUREMENT

"-Woekly GRAB Effluent Gross IREQUIREMENT' -MAXIM .* .: -" 0040010 .0 '. MINIMUM __" ____. MAXUM ________ ___Solids total suspended AMPLE ....- 3.1 3.1 19 0 01/30 GR MEASUREMENT

.0053010 PERMIT.

• u MW. eqR eong : Re. Mon. Monly GRAB Effluent Gross

.A. p ..b L *A ... *Oil & Grase SAMPLE ..4 01.4 19 0 01/07 GR MEASUREMENT

,__0055610 PRm -T,' ." -16 .20 Effluent Gross

_ __r_-

• _,_ ,_" SODA AVG DAILY MX edG Chromium, total (as C SAMPLE -.. <0.0021 19 0 01/07 GR MEASUREMENT 0103410 PEI T02 We" --GRAB Effluent Gross REQUIREMENT , "_ -'_"_-:" -. ___ _"_"" -DAILY MX L ., SAMPLE ..... .,...., .2 9 0 0/7G Copper, total (as Cu) MAUREME 0.024 19 0 01/07 GR 0104210 .-:; GpRAMB *.,-$ "!Q Effluent Gross REQUIREMENT

... ....-.-m..L. -Weely GRAB Zinc total (as Zn) AMPLE --- 0.003 0.004 19 0 01/07 GR MEASUREMENT 0109210 -PERMiT'-

..* -..-. .213 ..433 Effluent Gross REQUIREMENT:*

_ --V DAILY Mg".J ---4 " .* ... -NAMEflTTLE I ceffiy under penalty od lw tU documam and all aachunm imwe prupared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER iren a supeaon Inaccordance fth a stm designed to mstau didt qumllied peneil_Benjamin P. Younan who manage the syst h o dose persom nsirectly respotsnbe for gadlihang die kdomallon.

te 06/21=e13 bzdormallon wialubmlld I to thde be ot my lvowldege and IoM. Inte. nomade. and ompnlole.

Iam Sl15FRINCInPLE Plant Manager aware Mat dire ame algnticam penaf for lo tng taoe bUormallor.

Indcslnkg the postaly of I CUTIV OFFICER OR AREA NUMBER MWDDIYYYY TMOR PpOFF'o -m laend Inftslonment lor knmn violatins.

AUTHORIZED AGENT CODENME MIDYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hers)1. Monitoring data for outfall 001-0 Is Included on attachment.

EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1AM2012 PAGE 1 POOR QUALITY ORIGINAL NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 6055S-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron.:.IL 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: 61010 MAJOR (SUBR 01) CS COOUNG SYSTEM BLOWDOWN External Outfall* *

• NO DISCHARGE j*MONITORING PERIOD MMDIYYYY T MMIDDIYYYY FROM I 05101/2013 I TOI 05/31/2013 I AI IN: ,I/:V il"FR UEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE>< ANALYSIS Oxidants, total residual SAMPLE 0.03 19 0 01/07 GR MEASUREMENT 3404410 PE.RMI .05 34441 .-m : '-.* " -l,,p m .- Wekldy GRAS Effluent Gross REQUIREMENT DAI_____ _-_'__.. : -NLY MX -- .e.y G.Priority pollutants total effluent EAUMLE 500 50008 10 .Req Mon.*. Req. G..A Effluent Gross REQUIREMENT -DAILY MX, IWd -DAILY MX WwY GRAB Flow, In condui or thin SAMPLE S 20.16 274 3 ..... 0 01/01 CN treatment plant MEASUREMENT 2.62.630 011C 5005010 P1 0eq. Mon- Rec. Idbn-Effluent Gross REQUIREMENT SPOA AVG DAILY W.id/d .-Dany CONTMN Chlorine, total residual SAMPLE500 50060 10 PEMTA"EUIE

... MX Effluent Gross REREMET ANT .__ _.__ ._ ...._ _ _ _ __ ____ __ __ __ __ _ __ __ __ _ -"___" __ " __ __" _ _____*__

___.. ..... DAILY MX .-Weekly GRAB HriSAMPLE 5 Hydrazine MEASUREMENT 500 8131310 PERMIT **,., .011 .m27 m. Daly When Effluent Gross REQUIREMEINT 3"_ _ *_"_,_ODA AVG DAILY MX Discarn GRAB SAMPLE MEASUREMENT

• PERMIT .REQUIREMENT'

• _ !. _SAMPLE MEASUREMENT,* PERMIT REQwREMENT:

"_ __ _ " _ _..... _. ._"_. ._" NAMEIIT.E I cWity under penaly of law Va thOf documnt and 5 atmr were pepared undertTELPHONE DATE PRINCIPAL EXECUTIVE OFFICER ltcIJon or supe slonlnaccordance w.ith a B dten to asueaM qMalifiedI p -If -,ae--o_.PHONE4I6-3TE Benjamin P. Youman propet 95111and evaluOs the Informatin srubmited.

Based an fly WqIry of tMe pesmon or peros011 e 815 4030 0-2/2013 whr o manage th syWUaI. at those perons directly respomib for gatodn the ftInformation.

the /S! E1F"LIE Ptant~na~er Ivn~ht~mm Pniismu subirad I.to the best ofmy Inowede nd befie. tue. ac=WA. andcnit lan ARANUB5nMD Plant Manager .lr ~ o ~ ~ ~ ~ ~ ~ iw ~1ICiI E FCER OR REA W_______ n md b t for knano viorm AUTHORIZED AGENT C NDiY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/08) Previous editions may be used. 1A/2012 PAGE 2 O POOR QUALITY ORIGINAL PERMITTEE NAMEJADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvllle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 Norlh German Church Road NATIONAL POLLUTANT DI*ARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUME MONITORING PERIOD MM/DONYYY -j I MMDD/YYYY STORMWATER RUNOFF BASIN External Outfall*NO DISCHARGE E .FROM I 05/01/2013 05/31/2013 I I Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS Solids, Total Suspended SAMPLE 500 MEASUREMENT 0053010 PERMIT. .' .15 30m:..' "". ' " O8DfAVA ..-DAILY MX° , .-.w GRA Effluent Gross REUILREMENT , ,*D, ,G- DM-GR SAMPLE -Solids. Total Susp I MEASUREMENT 0053080 a- -_-.... .. *.-.R T .-R..Uoo " GRAB Other Treatment.

Process 3" We. AP..Complete ., -" ... .""__....Chromium.

hexavadent SAMPLE "500 (as Cr) MEASUREMENT

-_01032 10 -R .. -, , ... .. ..___ ,__ ,01 .OAAG .0LYX inq30 IDaI RA Effluent Gross REQUIREMENT YOf .041Dil Chromium, o SAMPLE Soo (as Cr) MEASUREMENT 0103410 PERMOI, T"2 mg/L GRAB Effluent Gross REQUIREMENT 30DA AVG DALY MX R Copper, total SAMPLE .5 (as Cu) MEASUREMENT 01042 10 PERMIT =025 .041 Effluent Gross REQUIREMENT 0 -,,DA AVG DAILY MX. m.... Daly GRAS Iron. total SAMPLE .. .. ... --I500 (as Fe) MEASUREMENT 0141 PERMIT GRA 0104510 "- R.EQUIRMEN

_...._._, ______ ,, -::.',** .. ",,, .I .....YM...Da.l~y GRAS Effluent Gross ,REQU-REMENT

--." DAILY I1 , Lead, total SAMPLE Soo (as Pb) MEASUREMENT 0105110 PERMIT 1 "' .063 :.298 Effluent Gross REQUIREMENT'-

-. *.- MX Da""""GRAS NAMEnM.E I centy under penalty of law Ow Ofl docurnme and al attachmentar m prepard widar my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction a, supevisiotn in accodance vaU a system designed to assure Me~ qiiUm parsonnel

__propelty gamer and evakluea ft Inom uftinmed.

Based an my kfrquiy of the pemon or pemrsons 9Y5 406-3700 Benjamin P. Yoursn who managmem system or mose persona dkly r*spwoaato fr goal-e-g -the idomionf 06/21/2013 enformatn

__ftntid Is to ft bo o my loled and blief. lim, acuMLand Cmplte. Iain SI RE,0yPRINCIPLE Plant Manager aware haI tere am signiicarU penalties for jbkftkn false Information.

icamdng the pos.syol ofITI OFFICER OR AREA-Ean PAhN fione mand inprs sio'arM for bwowig vfalatons.

AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference oll attachments hers)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemlcal Metal Cleaning Wastewater was discharged this month.2. No Fire Protection or Service Water System Drain Water was discharged this month.3. No Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 1 POOR QUALITY ORIAIIN1.PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, 1 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTNM 7 n rm n.JFNV RP:: NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD I HMMDJu n I I MWDD/YYYY STORMWATER RUNOFF BASIN External Outfall NODISCHARGE EZJ FROM I 05601/2013 I TOI 4 05&31/2013 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS Nickel, total SAMPLE ....... So (as Ni) MEASUREMENT 0106710 *E0AV .V8 DAILY'MX ..il. .-Day- GRA.Effluent Gross REQUIREMENT 300A AVG _ __ _ _ __Zinc, total SAMPLE 5...00 (as Zn) MEASUREMENT

..____ _-_5_0 0109210 PERMIT. .04. -. ;AMaly. GRAB Effluent Gross REQUIREMENT

-. -300A AVG DAILY M.X t g/I. , D A Oil and Grease SAMPLE ....... ..... 500 MEASUREMENT 03582 10 5PERIT 2D* 1.2 When* "* "300 AV " DAILY MX ," .-D ischargling9 RA Effluent Gross REQUIREMENT:

__________

___ SDA AVG DIYM oi IA Flow, in conduit or thru SAMPLE ...... 500 treatment plant MEASUREMENT 500501 0 PFMIWT Req. Mon. " Req.DAi. EST.MA Effluent Gross REQUIREMENT, 3DAAVG DAILY MX- F -'*:" ESTIMA SAMPLE MEASUREMENT PERMIT REQUIREMENT SAMPLE MEASUREMENT REQUIREMENT:

..I___.____.___-___-_

SAMPLE MEASUREMENT REQUIREMENT " .-"__"_".. " ""___"_""'

MNAMTIE I Certify under penalty of law mt this docwner and an sfladitrnerl were Papd Uwder my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER directon or upevion in accordance with a systemr desgned to assure qud PemrTonnELPeONElD pmpedy gather and evalute suibrred.

Based on my iqtyf o Person o Pesons 815 406-3700 Benjamin P. Youman ft, "mange systeme or Ose persons dirctly rasponsria for gathein te Onlomtatondo.

06/21=013 tratmiasion aubridua Is. to ft beoo of nay knasriedg arid balief. true. accurateana d cple.Iami Sir ' RI~IINCIPLE Plant Manager ware Iat them re alsignfIcant pertaites lot sunbtnrg tabse Infonnation, indudtrag me posaslityof (ECaC E OFFICER OR AREA TYPED OR Sfe and risnVfo nm vlo AUTHORIZED AGENT CODE NUMBER MM/DDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/120"2 PAGE 2 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 May 2013 Page 1 of 2 MONITORING DATA: WBD CRock River DATE Temperature mgd Flow deg F cfs 05/01/2013 81.1 11.34 18,600 05/02/2013 79.7 16.04 17,500 05/03/2013 66.2 23.76 17,000 05/04/2013 75.2 26.19 16,600 05/05/2013 75.2 22.02 15,900 05/06/2013 76.4 14.84 15,200 05/07/2013 74.9 23.10 14,500 05/08/2013 78.7 16.67 14,000 05/09/2013 78.7 22.51 13,400 05/10/2013 77.5 17.36 13,800 05/11/2013 80.4 26.58 13,800 05/12/2013 80.4 21.63 13,600 05/13/2013 78.3 16.68 13,500 05/14/2013 88.3 21.31 13,400 05/15/2013 88.3 18.98 13,200 05/16/2013 83.8 19.21 12,800 05/17/2013 80.4 14.09 12,200 05/18/2013 84.0 26.77 11,700 05/19/2013 85.7 21.37 11,400 05/20/2013 87.2 14.24 11,200 05/21/2013 87.2 21.13 10,900 05/22/2013 86.0 19.06 10,500 05/23/2013 82.3 20.79 10,300 05/24/2013 76.1 21.60 10,200 05/25/2013 75.0 27.46 10,000 05/26/2013 77.4 15.05 9,810 05/27/2013 79.0 22.63 9,740 05/28/2013 85.8 18.72 9,790 05/29/2013 86.5 20.27 10,200 05/30/2013 88.2 22.09 10,200 05/31/2013 87.8 21.36 10,300 K:\BYR_CH\BYRON.DB\Clerk\4onthly Discharge Monitor Rpt\2013\May\May 2013 ATTACHOI.docx ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 May 2013 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of May 2013.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 11.2 mg/L on 05/06/2013.

The CWBD TSS value was 3.1 mg/L on 05/06/2013.

5. Rock River flow for May 2013 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in May 2013. (Special Condition 15).K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\20133\May\May 2013 ATI'ACHO1.docx Exelon.Exelon Generation Company, LLC www.exeloncorp.com Byron Station Nuclear 445o North German Church Road Byron. IL 61010-9794 July 18, 2013 LTR: BYRON 2013-0096 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number IL0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of June 1,2013 through June 30, 2013.If there are any questions regarding this report, please contact Ms. Zoe Cox, EnvironmentaVRadwaste Supervisor, at (815) 406-3035.Respectfully, Benjamin P. Voum?Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments bcc: Kevin Hersey -Sr. Environmental Specialist

-Cantera (electronic)

Zoe Cox -Environmental/Radwaste Supervisor

-Byron NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMrrrEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 IL0048313 PERMIT NUMBER A01-0-DISCHARGE NUMBER MONITORING PERIOD I MMIDWYYYY

_ MMIDDJYYYY DMR Mailing ZIP CODE: 61010 MAJOR (SUBR 01) CS DEMINERALIZER REGENERATE WASTE (001A)External Outfall* NO DISCHARGE

[ 'FROMI 06/01/2013 I TOI 0&/30/2013 I e n ATTu: Zoo CoxIENV SPEf'PARAMETER QUANTITY OR LOADING 1 r 1 VALUE VALUE UNITS VALUE I 6 4 I I Solids. Total Suspended 0053 10 SAMPLE UPACIIAURI1:PT MEASUREMENT1..

FERW T ,:..., FChromium.

hexavalent SAMPLE ......(as Cr) MEASUREMENT 01032 1 0 PERMIT .' ",***Effluent Gross REQUIREME

---Chromium, total SAMPLE ......(as Cr) MEASUREMENT 01034 10 EMT*Effluent Gross ..UIREMENT

-I -=Copper, total SAMPLE ....(as Cu) MEASUREMENT 010421 0 .- .,. .,., -, -.. ,rn.Effluent Gross REAUIREMENT " .," "'Iron. total SAMPLE ...................(as Fe) MEASUREMENT 0 1 0 4 5 1 0 -I .I ..I, -, -.. : -..... ..Effluent Gross REQUIREMENT

, Lead. Total SAMPLE ........................(as Pb) MEASUREMENT 01051 1 0 PR. PEMIT ._. ...'. 21 .-'.Effluent Gross REWUIREME T * --.T-.. ---Nickel, total (as Ni)0106710 C~HI SAMPLE MEASUREMENT It Nt MEASUEMEN--iIPPRMrr NAM.~ ..== ......... llýNAMErnTrLE PRINCIPAL EXECUTIVE OFtICER Benjamin P. Younan Plant Manager 1Mw oR PRINrM I cattify under penalty of law that t=ds document and all attachments worn pnqeae under my direction of supervision at accordance with a system designed to assure thaO qualited personnel property gather and evalute the inf onnation subnfed. Based on my inquity of the poeson or persons who manage the system, or those pers"os d W responsi for gathedng the nf ormation, the Information submitted is. to the best of my knowlodge and bewef, tree, accurate, and complete.

I am aware that there are sinlfica penalties lot submtltting false Islomialn, Incltefudjng the poesitbliy of tee and IMrpslonmen for knowing violations.

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed 30 of 30 days during this month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4460 North German Church Road Byron, IL 61010 ATTN: Zoo Cox/ENV SPEC DMR Mailing ZiP CODE: MAJOR (SUDR 01) CS 61010 110048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDIYYYY I MMIDDIYYYY DEMINERALIZER REGENERATE WASTE (001A)External Outfall* *NO DISCHARGE FROMI 06/01/2013 I TOI 06130/2013 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER

___ __N. OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Zinc. Total SAMPLE ... .(as Zn) MEASUREMENT Soo 0109210o..

PERMIT ..., ......._.. .. ....-2 , -. : Effluent Gross RQUIR EuNT , 0 _ ." bDA AVG. DALY MX" , ' : : " -.A Flow, in conduit or thru SAMPLE 0057 0.301E treatment plant MEASUREMENT 0.057 0.243 3 .........

0 01101 ES 50050 10 RPEReT , *.q. Mqn; Re, e, Mon: ..... -. .Effluent Gross REQUIRdENT

• AVG PAILY:1.. "T " -" -': ":"'"" * " " NI SAMPLE ------MEASUREMENT

________ __________

REQUIREMENT

.p ... .. ..SAMPLE MEASUREMENT" ..___- .___"_. ... .REQUIREMENT

--:; .... ...-.... ._ ....PE M T. ...... ......... .., ..., .... .. :, ..i .: ' : ! ' : SAMPLE MEASUREMENT Sp.EQUIR.EM T -F -.-. .:,:_.SAMPLE MEASUREMENT

'__._'_'.

_"_" _-_ " PERM .... ... , ...._ _.-. .....SAMPLE MEASUREMENT I. I : ...., ..... .LEAUREMENT

-.,-,Y -.-.....MESREMIIENT NAME/fTILE I cetiy under penaly o law that this document and all atladunents were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER d irecun m a supe wao in accordance with a system " to .th i qua led peT EonnLEPHO properly gather and evetute the m ormnatlon aubmitted.

Based an my irnqusY of the person or p 81 4E06-370 Benjamin P. Youman who manage the system, or those persons directly responstote for gathering the mtomalion, tte F 0--.- =.1 07/18/2013 nformatlon submitted.

to the beet ci my knowledg, and bfllf. true. accurate, and complete.

an SIGNAEOFVM CIPL T Plant Manager aware that there are signiftant penates for submitting false Information, Unudn tle posis 4 of EXE TIVE OFFICER OR AREA N 13 Sa ne and for knowing vdaliea.ns, AUTHORIZED AGENT COD NUMBER MM/DDYYY_COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flows for June 2013 are estimated based on July 2012 values due to totalizers being Out of Service. The totalizers are an obsolete model and work orders are In place to find replacement totalizers and get them installed in the system.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)DMR Mailing ZIP CODE: MAJOR 61010 PERMWTrEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTNW 7n IL0048313 PERMIT NUMBER I B01-O I (SUBR 01) CS I DISCHARGE NUMBER D_ýISCHKARGE NUMBER I MONITORING PERIOD MMIDDINI MMIDDIYYYY STP PLANT EFFLUENT (FORMER 0018)External Outfall* 6

• NO DISCHARGE FROMI 06/01/2013 I TOI 06/30/2013 Il i QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE BOO. -Day SAMPLE 0.38 0.40 26 ...... 5.5 7.0 19 0 02/30 24 (20 Deg. C) MEASUREMENT 0031010 I5.3 10.5- .0 T.Effluentt Gross REQUIREMElNT 300&6RA A I AILY.MX ._____ OA AVG. PAILY W:~ wi~~rMpf O~pH SAMPLE .............

7.52 7.60 12 0 02/30 GR MEASUREMENT 0040010 " "-PER4II .." .* .' " * " o --, Effluent Gross REQUIREMENT

.. > .N UM :."__:__".

.,..MUM -........ ., Solids, total suspended SAMPLE 0.23 0.31 26 2.9 3.1 19 0 02/30 24 MEASUREMENT______________

_____Effluent Gross REQUIREMENT S,,A vG .PALYMX -

AjLY. " i--g.. ..r .C '2 05ow 1 in conduit or thrR SA3,IMPLE*.

.... .FwinodtrhrSAPE 0.008 0.014 3 ...0 01/01 CN treatment plant MEASUREMENT 0____ 0.014 3 0 01_01 _ _50050 10 a..*- ,p. ., -R=. -=,, Req. h" ...... -'- ' ...Effluent Gross REQWRMU IT 300A AVG. .-DALY MX 73;_____ _____~SAMPLE MEASUREMENT

.. .. -......... -SAMPLE MEASUREMENT

• PERMIT-. ."- .-. ". "_____________

R"EQUIREM04T

._ __________

SAMPLE MEASUREMENT,..PER .. ..: , -..- -.-* P*:: .:.. : -: .,, "....... ::__._:____

NAMETL..E I cattly under penaty of law dhud ds document and all attachms were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or SupeMWlniin acordance with a system designed to assure that qualied personnel Spcoperly gauer and aletyo lae tht e nfdonsubmittent a Sed a n myentquryd epe-onorpem, .815 406-3700 Benjamin P. Youman who manage p te systemr on 1aute persomans auy msponsit ad gatherng te SnINatR, the 07118/2013 information submitted is., to tie best of my knotedge and belief. true, accurate.

and complete.

I am SIGNN _URE O0_ __NCIP-LE Plant Manager sware that there are slgndicant penalties for umnittmg false infomnati, Includin the porsllty ao EXECUTIVE OFFICER OR AREA NUMBER M/DD/YYYY TWDOR PIMM ,~ line and imprisionmest for knowving AUTH'ORIZED AGENT CODE N M E MD)Y Y COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 29 of 30 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCAT1ON 4450 North German Church Road IL0048313 PERMIT NUMBER C01-0 I DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS WWTP (FORMER 001C)External Outfall 61010 I MONITORING PERIOD MMIDDIYYYI MM1DDIfYYYY FROMI 06/01/2013 I TO I 06130/2013

• NO DISCHARGE

= ...I Byron. IL 61010 ATTN: Zoe CoxIENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF YP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALY TYPE Solids total suspended SM...... 6.4 7.4 19 0 02/30 24 MEASUREMENT 0053010 7 PERIT --pMM 36*.' "' "'.*. 1 0 Effluent Gross REQUIREMENT-

._._., 300DA AVG Chromium, hexavalent SAMPLE .. ...... 500 (as Cr) MEASUREMENT 0103210 .P"MjT .2...."-"- " "e" .v- : '.. *l A Effluent Gross 7 R5,UIIUEMEIl'

"... ' A V... .' ..- K -..Chromium, total SAMPLE ............

.....(as Cr) MEASUREMENT 0103410 2 ". * * ... ..- -: ... , .Effluent Gross .300A AVG -AILYXI " " " ......" -Copper, total SAMPLE 50...... S (as Cu) MEASUREMENT 0104210 77* PERi * +.. *.*..* .!..q. -.1 Effluent Gross REQUIREIEN..

,.....-......

.--..." 30DA"AV% ... '.- LY.MX ",......Iron. total SAMPLE .... .(as Fe) MEASUREMENT 0104510 pE1wrr .--,- .., .* " .... ... -,- -Effluent Gross XR..IREMENT

-_.. ..,. -..." " -.-.-Lead, total SAMPLE ... ... 50S (as Pb) MEASUREMENT 0105110 2-. P " .AAV" ",D J'YM- m _'__ _"-., Effluent Gross REQUIREMENT " .0DA.V D:-.A.LY Nickel, total SAMPLE ...... ...... 500 (as NQ MEASUREMENT 0106710 OIT .*.,_ 1 2'.Effluent Gross :.REQUIREMENT " 0-' --4, .O.... DA.LY......

• ....IAME/'TTLl.E I certify under penalty of law that this docwnent and all attachments were prepared under my TELEPHONE DATE PRINCI,1PAL EXECUTIVE OFIFcERfi direction supervisma In accoorance with a system designed to assure #a0 iuafi'id persnnel Pprey gather and evalute Me infonnation submitted.

Based on my inquy of the pero or persons , 815 1406-3700 Benjamin P. Youmnan who manage Ing systern, or those persons directl resposb lot gathrn the wlornlation, th 07/18/2013 information submitted is, to the best of my kowledge and belief. true. accurate, and complete.

I am MG_'__F I_-CIPLE Plant Manager aware that there are significant for subnftg false infomation.

including.the possiblily of EXECTIVE OFFICER OR AREA fi ne and imprisionmant for Mowin violaiias.

AUHRZDAET C4D NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outfall 20 of 30 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT'EE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 44S0 North German Church Road Byron. IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 1L0048313 PERMIT NUMBER Co010 I _DISCHARGE NUMBER F MONITORING PERIOD MMIDDIYYYY I MMIDDIYYYY WWTP (FORMER 0O1C)External Outfall** NO DISCHARGE E ...FROMI 06/01)2013 I TO I 06/30/2013 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS F ANALYSISE Zinc, total SAMPLE .............

500 (as Zn) MEASUREMENT Effluent Gross RlUIREMENT

........._"_ T30DA AVG. DAILY MX Row. In conduit or thru SAMPLE 0,024 ...... ......treatment plant MEASUREMENT 0024 0.041 3 0 01101 CN MEASUREMENT Effluent Gross MXEURMN PD V ~ ~~* Mg ~1*SAMPLE MEASUREMENT SAMPLE MEASUREMENT MEAQUIREMENT-SAMPLE MEASUREMENT

• -, PERMIT .... ..: "__ _ _ _ _ _ REQUIREMEW.

A___SAMPLE MEASUREMENT____

--PRMIT-. .SAMPLE MEASUREMENT_____

_____ _____________________

_____"~MIT .... .. 7.-K.NAME/TITLE I cartRy under penalty of law hat to documenm and al attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUiVE OFFICER drecbln Of SpMiOn in accarance with a system designed to assure dao qualified permonnel r P.perty gather and evahl fte Information submitted.

Based an my Inquiryof md th pero or persons 81 407/37002 Benjamin P. Youan whosmanageteSystem, or mose persons dIrectly responsbwe lor the iomatl. 07/18m013 mformadon submitted Is. to mae best of mtr bnowledge and belle'. true, accurate, and complete.

Ilam SIGNAV OF P CPLE____________

Plant Manager aware that there are aignffea penales tor submftng talse infortaio.

ic me posalt EXECUTIVE OFFICER OR AREA OR PCTE tne and kntpsoent tof knowing vilations.

AUTHORIZED AGENT [CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

L 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER D01-0 F DISCHARGE NUMBER MONITORING PERIOD I MMIDDINYYYY I MM/DDJVYYYY RADWASTE TREATMENT (FORMER 001D)External Outfall*I*NODISCHARGE E: ...FROM I 06/01/2013 1 TOI 06/30/2013 I i I I ATrN: Zoo CoxIENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TYPE SAMPLE ...... 2.4 4.1 19 0 02/30 CP Solids tota suspenda MEASUREMENT 0053010 PERMfIT. .. .,.T*- , 15- .'. " .. ..Effluent Gross .eQuiReENT

-""" .." -300. AVG PNYMX :..Row, in conduit or thru SAMPLE ...002 ......0..30 11 tetetpatMAUEET 0.022 0.024 3 ...0 01/01 CN treatment plant MEASUREMENT

_____ _____ ___ _____5 0 0 5 0 1 o0 P-. u M i T "., R eq .M o R eq. 7o. .-.... -.' .". ."--Effluent Gross -REQUIREMAENT 39W j AY -. AlYX __SAMPLE MEASUREMENT

__ _ _ __ _ _ _ R QUIREME T ..;... .-: ... -- ....:- ._ .... ....-,*.. -... -,.:..SAMPLE MEASUREMENT D m u ' " .-..."-" ' -." I .:"1 " ,." '- ." I. **S*-,m E , .,, ....... ,.. .-. .:, t.. ., SAMPLE MEASUREMENT , .. .* .-.... , I ". .: -' , :... ..-: `::. _,__ _ REQUIR -.. *_". .: , _ _.._-'_...

... .. ...-SAMPLE MEASUREMENT P. "MFr. ...*.

...: ... ............ .- ...... .- ... .. ,. -. -.-, ...- -. ..... .. .... ...... ' .::-'::: -:. ..,______________REQUIREMENT A. ____ ______ ---------__________

____SAMPLE MEASUREMENT PERW .-.NAMEa .E I cedy under penalty o law that due document and al attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER or supervtslon in accordance with a system designed to assure that quaified B gather and evalute the info.mauton submited.

Based on my Iily d the person Or persons8151406.3700107/1 Benjamin P. Youman wh'o manage tUe system.n or those persons dirctly for gathering the inforlmabn, the 07/118=13 Information submitted!

is. to Ehe bes of my Icowleoe and befiet. tue. accura, and complete.

Iam OF PI CIPLE _ _ _Plant Manager aware that there am signilicant penalties for sutning false lnformaion.

including the PmMY of EXECUTIVE OFFICER OR AREA OR -fne and lo owing violations.

AUTHORIZED AGENT CODE NUMBER MM/DDjYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 5 of 30 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/8/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60655-5701.

FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER DMR Mailing ZIP CODE.MAJOR (SUOR 01) CS STORMWATER (FORMER 001 E)External Outfall... NO DISCHARGE 61010 S.MONITORING PERIOD UM/DD1WYYYV M M1DDYYY FROMI 06/01/2013 I TOI 06/30/2013 I ATlN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER

____OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solis. total i SAMPLE .........

5..MEASUREMENT 0053010 1PE5rI" m. , .30 Effluent Gross REQUIREMENT

... .___"_""__

300A AVG DAILY'M).

' * ........Solids,SAMPLE

...... ...... ...... 25.2 27.0 19 0 01/07 GR MEASUREMENT 0053080 Other Treatment.

Process R1U -e G+.Complete _____ _____ 4~~DA( Ath ~- ____Chromium.

hexavalent SAMPLE ..500 (as Cr) MEASUREMENT

...... ...... ......_Soo 0103210 :p -"+ * -" ...... ....- ' : 2 '" ily" " ,: " Effluent Gross .REQUIREMENT- " --. ., .", ' 3ODAAV Q DAILY M ,, _," Chromium, total SAMPLE 0 (as Cr) MEASUREMENT

...... 500 0103410 , ..... .1 .".....Effluent Gross RE"UIEP ..-..- ' -..ODA AVQ ..ILYM '- .Copper, total SAMPLE ..... 5 (as Cu) MEASUREMENT

..- 500 0104210 >:P IIT..IT '" "'- " -"' .s- : Effluent Gross REQUIREMENT , " .:;,A V ,L , ,. .Iron, total SAMPLE ...00 (a e A P E.... ..... ......nl (as Fe) MEASUREMENT

5.0 01045

1 0 " I " " .-.- ,:" .. .5 Effluent Gross .RE UI.EME"T " " .". : -OA.j" Y".X* ..Lead, total SAMPLE ......................

.'1 (as Pb) MEASUREMENT 500 0105110 " , -- .2 Effluent Gross REQUIREMENTS', ."'" -... -. ,....- -30DA AVG --W NAMEITITLE I centfy under penalty Of Law thaO tho docmeun and al anachrents were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER drectlon 0r Sup o I aMo-dance with a system designed to assure that quamted personnel

__PNDA propery gai11W and evaue fte mitomma subnmt .BaSe on my hquiry d the persm o, pemrsona1 406-3700 Benjamin P. Youman who manehystem te person directly spo tor atengnoe iomon. the , 815 406-3700 07/18/2013 Wmatinaon subrmeite is. to fte best as my knoattede and belef. t=u, accrate, and compete I am S GNA E OF PPICIPLE ________________

Plant Manager awam th'i tre arm sgdiant penatoes for subrnttkg the pos14telty EOFER OR AREA TWED.O OR PMCD_1 rine and pfnionment for knowing violations.

AUTHORIZED AGENT MODE NUMBER M/D/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow existed through this outfall 6 of 30 days during the month.,3. Theem was discharge of Fire Protection drain water durina the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 116/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER E01-0 F DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUIR 01) CS STORMWATER (FORMER 001 E).External Outfall 61010 MONITORING PERIOD MMIDDIYYYY MMIDDMYYY FROMI 06/01/2013 JTO I 06/30/2013

• *

• NO DISCHARGE

= ...QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TYPE Nickel, total SAMPLE ..........(as Ni) MEASUREMENT 0106710..., .... .... ,., 1 2 Effluent Gross REQUIREMENT

..300A AVG DAILY " : D.lyG'A'Zinc, total SAMPLE ...... ....... 500 (as Zn) MEASUREMENT

.: .T... I.. ........... .... .... .-. -.0109210 " RERMIF .": " ...;. ,... .. ..*, 1 .. ..Effluent Gross REQUIREMENT..

._.-_300AAVG DAILYMX':

"- " " -. -Flow in conduit or thru SAMPLE 0.355 0.731 3 ...............

0 02/30 CN treatment plant MEASUREMENT 500501 0 P.. PIRIl1" Re* .P 4,. Req. Monm. ".'.," CN'."" Effluent Gross REQUIREMENT ,QA AVG. 'ALY.,M. : " ........ " ..T.. : " " Month'.SAMPLE MEASUREMENT SAMPLE MEASUREMENT

.,REQUIREMEN

., .. , , ..SAMPLE MEASUREMENT p w .r ... .-.-.*.. ..... " ... -,':" REQUIRE ENT .. "" ..... .:..J-.- , "-,_ "" ": " _..

.. ... .. ... ..... ........."..',...:...".'.

-..... ........ .... .SAMPLE MEASUREMENT

.R M .,: : -. .-.- -' :, -!. ..- , ..]'- .: '-: ..: .. i .... -. : I.: : -: " ..-.' .. : , , ..-"... .-1... 0.. .' : ._ ,. V.. .,.- 'A:.:.;'NAME/TtT1.E I certify under penafly of law tha this document and all attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUtIVE OFFICER drection or supeision in accordance wia a system designed to assure What quailed personnel Iproperly gather and evabute the infonnation submitted. an my inqky of tre person at persons El, '# 8546370 Benjamin P. Youmnan who manage the system. or Viose persons dlrctly responsible for gatherang the information, the 07/18013 information submitted Is. to the best of my knowledge and be lef, true. ac irate, and com plete. Inam SIG N --RE O F " P P " Plant Manager aware tat here are signhtcAnt penalties for subawling lalse mfonmati, Incding the possifbty ci EXECUTIVE 0 ICER OR AREAUMB.-lme and pnnl nowg wsts AUTHORIZED AGENT COD NUMBER M_/DD/__YY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. No Closed Cooling System Drain Water was discharged this month.2. No Service Water System drain water was discharged this month.3. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Cleaning wastewater was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMJTTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 L IL0048313 PERMIT NUMBER I 1 001-0 I DISCHARGE NUMBER MONITORING PERIOD M COOLING SYSTEM BLOWDOWN External Outfatl* *

• NO DISCHARGE FROM I 06101/2013 I TOI 060=13 I ATTN: Zoe Coy]ENV SPEC______________

____________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER FO. OF TYPE* VALUE VALUE UNITS VALUE VALUE VALUE UNITS AALYSIS Temperature, water deg. SAMPLE ... .. 91.6 1 0 01/01 ON Fahrenheit MEASUREMENT

_........._91.6_15 0_0 0001110 ... IMII Fq. M11.Effluent Gross MOEQUIR EMEN "_r"_ "_"... _.. __.... ,'. * .-" ,F .' :? 1 1'" " pH SAMPLE ...... ... ..... 8.46 ...... 8.76 12 0 01/07 GR 0040010 'z-':.PER..

I .. .*": --: 'SU -6'. eI -...Effluent Gross REQUIR.EM" MINIMUM ..MAIMU .Solids, total suspended SAMPLE ....... .. 3.0 30 19 0 01130 OR MEASUREMENT

...... ... ...._.0_,0_90_0____

00,53010 -.:..J. ' " ,.ER.' :: ., ..-'MOn...-.

'..: e: , " :ýý .:: .;': ... " .; .-."r ... :z Effluent Gross .REQUIREMENT

.....301)A VG

.. ..:. fR..- .tt ... L.-Q , Oil & Grease SAMPLE ...... .1.4 -1.4 19 0 01/07 OR MEASUREMENT

<.<119 017_.- *. ... , ..-- .,. -.... -.. 7.o 7 00556 10 '* 10z1M- .' .:.1 ,, -.. Effluent Gross "0 , .-",:, ,.-..., _" ODA AVG DA, LY MX. Wa... ....Chromium, total (as Cr) SAMPLE .... 21.07.MEASUREMENT

_.002_19 0 01/07 GR 1.... nu .. : : -I --o -.:. , : , 01034 0 " .'Effluent Gross .REQUIREMIff..

-, .-,..W..-. .A'.Copper. total (as Cu) SAMPLE ..01900R.. .....REM"NT 0.024 19 0 01/07 GR MEASUREMENT 40___1 017_010421.0 0 ' .'-"_ _ _ _"_ _*_ ._ _ ._ _ ,. n",.I ; .... ~ 9. ky. O Zin.C, to ala (as Zn) *fliJ .. ... -.. ...0 0 8 90 07O MEASUREMENT

__.__4__008___0____7__

01092 107, 7 .. ,,,. ...... .4 -IEffluent Gross RIQUIRUSENT ...:_____-. "....QDA AVG DALY -:L ....M..' ."..NPAME/TITLE I catr*y under penalty ot law that alf docun, and all aeaclments were prepared my TELEPHONE DATE PRMWALEXECUTVE OFRFR dirction or superviion in accoomance with a systemn dege to assure tha qualroad pesornnel prolxS4 gather and evalute the ilorthation subn~ted.

Basen rmy bwutry at the person or peron 815 140-30'

,..Benjamin P. Youtman who manage the system Of Vtcs. persons drectly responsabe tor gathertngtle tnfomatla, te GP 8 mtoomatton submitted is. to the best of my knowledge and beaea, true, accurate.

and complete.

I a SIGNAnE OF PCL Plant Manager aware that there are signilicant penalties for subding slatseo nonmam, hcdng Mte pessay ol EXECUTIVE OFFYCER OR NREA , ao RPWM fine and ltnpiltonmeit flor lotvatri9 vloalions.

AUTHORIZED AGENT ODNUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hers)IA MonitForm da0- (r ou0fal1 001 -0 is included on attachmenu 1EPA Form 3320-1 (Rev 01/06) Previous editions; May be used. I!stm12 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 6055 -5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SBUR 01) CS 61010 110048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDYYYI MMIDDJYYYY COOLING SYSTEM BLOWDOWN External Outfall , ..NO DISCHARGEEJ FROM I 06/01/2013 TOI 06/30/2013 Byron, IL 61010 ATTN: Zoo Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE 1 <ANALYSIS

____Oxidants.

total residual SAMPLE .............

....... 0.05 19 0 01/07 GR MEASUREMENT 34044 10 "pF!M ...* ,,, .05 --*Effluent Gross REQUIREMENT.

' ." ." .QALY.M ."'e'. .(3R SAMPLE .........500 Priority pollutants total effluent MEASUREMENT

... e 500081 0 IERT .1 -I-. SJL 'Effluent Gross " QRE jiji lEM ___f_'" '. *.... ,AI&YM)( D.AN... X. .Flow. in conduit or thru SAMPLE 21 3 2154 3....... 0 01/01 CN treatment plant MEASUREMENT

., '. .'_r -_,5_ _ _'" .. .._" ' .N Effluent Gross ".REIOUIREMEINIT WqAAV-k ..,__ ...... ..Chlorine.

total residual SAMPLE ........ .........

500 MEASUREMENT

'Effluent Gross REQU __________

.PAll-VMX' mgI HydazneSAMPLE

...... ...... ......." Soo0 Hydrazine MEASUREMENT 8131310 N T * ." -__________

.0AAV ;"- 7 Wln.Effluent Gross ;"EQUIR EMW T .".:." _".-' " ..._ .- ': ' " AAVG.II-,.

SAMPLE MEASUREMENT OPUMIT ....REQUIREMENT

• _"'" *_" "_ " "" " " ' : " 'SAMPLE MEASUREMENT P.: ER-. rr°-L ..:.- .... ... ... ......;- ,. .. ... ' " ." " '-..__ _ _ REQUIREMENT

,. ...... .NAMEnnM.E I certify under penaly of law hat docunentad all attachmens were pelpre under my TELEPHONE DATE PRINCIPAL EXECLlVE OFFICER direction or superion in accordance with a system designed to assure hat TualE O perTnnelE properly gars and evalute the Inlormation submitted.

Based on my inquiry of tte person orpesns 815 406-3700 who manage tle system, or those persons directy responsibe for gathering mte informaton.

SIGNmRE. 1R20CIPLE_

Plant Marnagler infonmaion submitted is. to the best at my inowiedge and betel, true. accurate.

and compiete am EX TIE IPFFI E Rwa that ther ar significant penalties for submitting fals Infornation including the posablily of NUMBER, MM/DDYYY r line and imnrisionment for knowrnn Uintarionn AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hers)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITIEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN:, 7,-d "--=NV/I:k -QD=I'DUR Mailing ZIP CODE: MAJOR (SUOR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDIYYYY I I MMIDDYYYY STORMWATER RUNOFF BASIN External Outfall* * "NO DISCHARGE fMJ 1 .1 FROM I 06/01/2013

---

--- 4 ITOI 06/30/2013 I r PARAMETER QUANTITY OR LOADING VALUE VALUE UNITS VALUE Solids. Total Suspended EAMPLE ......MEASUREMENT 0053010 EIT Eff luent GrossREIRMN_____

SAMPLE ......Solids, Total Suspended MEASUREMENT 00530 80 .Other Trealment.

Process Comolete 1 / __- -_, _ ..-.- ..:-Chromium, hexavalent SAMPLE .......(as Cr) MEASUREMENT

_________01032 1 0 .~ .:.-::, Effluent Gross REQUIRE.ENT

_ ., .Chromium.

total SAMPLE .... .... ......(as Cr) MEASUREMENT 010341 : .. .t. ..1.Effluent Gross REQUIREMENT.'

.uopper, loutd (as Cu)0104210 Fftluant flrnLss SAMPLE MEASUREMENT

-4.... 1 Prm (T.I --Eflun Grosss~,~.~4

..J--iorn. total (as Fe)0104510 SAMPLE MEASUREMENT ttHtt-.4- .1 J.-.---J.

I P114411 R~OUIR~UrnJT Lead, total SAMPLE ..(as Pb) MEASUREMENT t*et 0105110 'PR I- -..Effluent Gross REQUIREMENT

` ________ -.NAMEInTTLE I cariy under penalty of law that tis document and al attachments were prepared under my PRINCIPAL EXECUTVE OFFICER direction or supevision in accordance with a system designed to assure th qualified pesonnel property gather and evalute the information subminted.

Based on my tiquliy of tie pensi or persons Benjamin P. Youman who manage the system, or those persons directly respaons tot gathering the information.

the information subimitted Is. to the best of my knowledge and beef. true. accurate, and comtlete.

I am Plant Manager aware that there are sncant penalties fotr SuMIting false inlormatimo.

including the poesilty of TVPED OR PARME I we and Imprisieru lot Itario g violsats.U0;MMENT1 AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection or Service Water System Drain Water was discharged this month.3. No Closed Cooling System Drain Water dlisharnnd ithis mnnlh EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/8/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvilla, 1160555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDYYYY I I MM/DD/YYY STORMWATER RUNOFF BASIN External Outfall NOOISCHARGE I-FROM I 06/01/2013 I TO I 06/30/2013 ATTN: Zoo Cox/ENV SPEC FREQUENCY_____________________________

QUANWTTY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER

________ ____________

__NOOF SAPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel, total SAMPLE ..........

...... ......(as Ni) MEASUREMENT 500 010671 0 pRI 01.Effluent Gross REQUIREMET'IT

.__.__ -__.._" __ -_. ..- -3)DA.'AVG QAILY MX .. * --.ra-"- -GRAB Zinc, total SAMPLE ...... 500..(as Zn) MEASUREMENT 500 0109210 PEMT-*...

.047.2 RA Effluent Gross REQUIREM-ENT

..., _-. .300A AVG.. PjIlYNI, M91 L ....-. .Oil and Grease SAMPLE .........

...... ....MEASUREMENT 035821 0 ". PEMIT"" -: G " F.IAB .5 0 ;. ...

DALYMX .- ..--.: , n -. -.Effluent Gross REQUIREMENT, 150i"" .1 DAIL -M".. " Flow, in conduit or thru SAMPLE ......treatment plant MEASUREMENT 5005010 le, -" " ." " .. .'Mon.Effluent Gross .EQUGIEe T .PAILY MX g. ;" * " -,.ismm'.,qn SAMPLE MEASUREMENT PERMIT .v ....SAMPLE MEASUREMENT. " 'SAMPLE MEASUREMENT NMETIE I certify under penalty al law that his document and all atta ments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER d5mctlon or euPefvision in accordance with a system designed to assure that qualffed personnel T Propert 9gather and evalute te information submitted.

Based on my inquiy of fte persones 815 4 07/8701 Benjamin P. Youman who manage the system, or those persons direcly responsilue for gatherin the inforna theo d 07/18/2013 inlormation submitted Is. to the best of my knowledge and belief. true. accurat, an complete.

1 am SIGNOURE OFPINCIPLE Plant Manager aware that there are significant penalties for tse ocludin the poasiblily of EXECUTIVE OFFICER OR AREN"rM oR wfumm faM and imprsiomet fr knom~g violations.

AUTHORIZED AGENT coo NUMBER MMDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. This discharge point was not used this month.2. There was no discharge ol processed steam generator chemical cleaning wastewater durng the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/612012 PAGE 2 ATrACHMENT TO COOLING SYSTEM BLOWDOWN (Ouffall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 June 2013 Page 1 of 2 MONITORING DATA: WBD CRock River CWBD Flow DATE Temperature mgd Flow deg F cfs 06/01/2013 86.1 21.55 10,400 06/02/2013 85.0 18.66 10,400 06/03/2013 77.8 19.69 10,100 06/04/2013 78.2 20.64 9,670 06/05/2013 79.4 19.29 9,390 06/06/2013 79.4 19.67 9,430 06/07/2013 79.0 21.51 9,270 06/08/2013 77.5 24.99 9,020 06/09/2013 85.7 25.38 8,710 06/10/2013 85.7 10.59 8,500 06/11/2013 86.0 20.54 8,210 06/12/2013 88.9 20.74 7,990 06/13/2013 88.9 20.33 8,420 06/14/2013 84.1 20.42 8,510 06/15/2013 87.2 25.44 8,320 06/16/2013 87.2 25.22 8,080 06/17/2013 86.6 16.76 7,780 06/18/2013 85.6 21.17 7,560 06/19/2013 78.7 20.58 7,430 06/20/2013 88.2 25.40 7,190 06/21/2013 88.4 19.89 7,280 06/22/2013 88.3 26.03 10,500 06/23/2013 88.3 20.86 13,600 06/24/2013 88.3 14.89 14,100 06/25/2013 91.6 22.95 15,300 06/26/2013 89.9 21.49 20,100 06/27/2013 89.4 23.09 26,800 06/28/2013 88.8 22.27 28,600 06/29/2013 85.9 28.54 25,600 06/30/2013 83.6 22.90 25,900 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2013\June'June 2013 ATTACH01.docx ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 June 2013 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of June 2013.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 30 of 30 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 29.3 mg/L on 06/10/2013.

The CWBD TSS value was 3.0 mg/L on 06/10/2013.

5. Rock River flow for June 2013 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in June 2013. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor RptA2013'June\June 2013 ATTACHO1.docx Exelon.Exelon Generation Company, LLC www.exeloncorp.com Byron Station Nuclear 445o North German Church Road Byron, IL 6101o-9794 August 26, 2013 LTR: BYRON 2013-0114 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of July 1, 2013 through July 31, 2013.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Beai~nP. Y a Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)

NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTN: Zoo CoxiENV SPEC DMAR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER Ao0-0 DISCHARGE NUMBER MONITORING PERIOD MM/DD/YYYY MMIDD/YYYY DEMINERALIZER REGENERATE WASTE (001A)External Outfall*NO DISCHARGE FROMI 07/0112013 I TOI 07/31/2013 PARAMETER><QUANTITY OR LOADING VALUE VALUE UNITS VALUE SAMPLE ...... ......Solds, Total Suspended MEASUREMENT 0053010 .r ." ......Effluent Gross REQUIREMENT

-.- ..... .Chromium, hexavaient SAMPLE ...................(as Cr) MEASUREMENT 0103210 jPER! ..... ....Effluent Gross REQUIREMENT

': Chromium, total SAMPLE .........

......(as Cr) MEASUREMENT 0103410 ., R " .E.. ..*.I E ff l u e n t G r o s s R 6 Q U I R E M El T _ ._ _ ._ ._ _ _._ _. ..Copper, total SAMPLE ... ... ....(as Cu) MEASUREMENT 0104210 -.. ., ....Effluent Gross REQUIREMENT, -. ......'I Iron. total (as Fe)01045 1 0 Fi:fh. rnt Arri.w.SAMPLE MEASUREMENT , 41J 2 PWT AEOUIRRII.IT

-I* :: .....;.tmpt I.Effluent ______ Gross, 4 1 Lead, Total (as Pb)01051 1 0 MEAMPLE MEASUREMENT 4 -- ~4 .I -* pERMr~.'DerAIaIaE!Ethr'v C-,*i E lluent, tmGos .-_____Nickel, total (as Ni)0106710 i::fhac~t rs MEAMPLE MEASUREMENT S4 1 -+ -p..-.*I.i Eff luent Gross 'REQUIREMENT F: NAMEnlTTLE PRINCIPAL EXECUTlVE OFFICER Benjamin P. Youman Plant Manager SnTYE OR PMUM certity under penalty of law that thos document and all attachnments were prepared under my lietiaon or supeoson in accordance with a system designed to eissure that quafled personnel Propenly gather and evalute the information submitted.

Based on my inqutiy of Mte person or persons 0no manage the systeM, or those pemona directly responsible for gathering the Information.

the nformation submitted is. to the bfet ol my knowledge and bel, true, accurate, and complete.

I am aware tt there are sigftcant penalties for sub9ittin laabe Information.

hiudding the posatlbity of.ine and imprlsionment for knowing violations.

TELEPHONE DATE-.7 IiU m W W WU m 815406-3700 08/26/2013 SIGNAlJ'E OF PRIf1LE EXECUTIVE OFFICUh OR AUTHORIZED AGENT-4 I COEv NUMBER MM/DD[YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. There was no discharge of processed steam generator chemical cleaning wastawater during this month.2. Flow existed 31 of 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6I2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEIADDRESS NAME Exeton Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvite, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313"PERMIT NUMBER I A01-0 I OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I DISCHARGE NUMBER I MONITORING PERIOD I MMIDDYYYY I MMDoiYYYY DEMINERALIZER REGENERATE WASTE (001A)External Outfall* **NODISCHARGE

! I! .4 FROMI 07/01/2013 I TO I1 07/31/2013-I lQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Zinc. Total SAMPLE.. ..(as Zn) MEASUREMENT 01002 1 0 vRM' I'.i " -I 2 .Effluent Gross REQUIREMENT

"" .: -. .. .30DAD,, A:GM4jYM) "ia'," Flow. in conduit or thru SAMPLE 0057 0243 3 0 01101 ES treatment plant MEASUREMENT 5005010 PERI MIT " Rqq. Mon. sq-Mon..."". " .' D.. ." -CONT I Effluent Gross 0EQUIAEMENr

.DAGYI MX ..-__..,,..SAMPLE MEASUREMENT

______________

• REQUIREMENT,___________-

--SAMPLE MEASUREMENT______________________

-_ _ -. I vs SAMPLE MEASUREMENT

_____________________

"__ _ _. W p , .-... .- .._ _ _ _* _. .. .., .... .. .... ., -... ., ... .. -. ,._ _.SAMPLE MEASUREMENT

• ......dr r... ... ..,.. 4 * ,-I:, .- .'_"____"""_

." ' ."" ...;; ." SAMPLE MEASUREMENT

.........

..... .... ....................

,..........

......... --.-r'.-" ., -..: .... .-.. .- * ' : ' Y :: :i. 2::" ,'. ,- .; .- :<0 *"" __ _ _ _ _ _ RQuIRM ENT- *-"-""-_ :.. .. ", ."_,. -___ .."----.NAMEITTTLE I certif under Penally df law that Oth document and anl eladhtenrts ware prepared under mtyTLPOEDT PRO41CIPAL EXECUTIVE OFFICER direch or superetsiminsordw=c wilth system designed to assure tat qualified peromonae 82621.UAMPLEPL infomation suib:mited is. to the beo of ..y knwle and belief. true. accurate.

and complete.

I am SIGNA1F.-...

FI.... P. .... ...;, ____. __. ___._.--.....

Plant Manager -daware tha there are significanit Penalties for stubmitting false informataion ncluding the posality d XC VE 0 CER OR AR UMEREAD/YY TYPIED OR pfwnw fne and lmprisioavnenl for knowing viciationsTOIE)

GN OENMBRMIDYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Refernence all attachments hers)1. Flows for July 2013 are estimated based on July 2012 values due to totalizers being Out of Service. The totalizers are an obsolete model and work orders are in place to find replacement totalizers end gal them installed in the system.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE?2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIR"E NAMEIADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvile, IL 60555-5701 FACIIJTY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER B01-0 DISCHARGE NUMBER DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS S"P PLANT EFFLUENT (FORMER 001B)External Outfall I *

• NO DISCHARGE 61010 MONITORING PERIOD[ MMIDDIYYYY MM.DDIYYYY FROMI 07101/2013 I TOI 07131=2013 l I ATTN: Zoo CoxIENV SPEC _ FREUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF T VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE BOD, S-Day SAMPLE 0.28 0.33 26 ...... 3.5 4.0 19 0 02530 24 (20 Dog. C) MEASUREMENT 0031010 .o.... 5, , 10.5 30 ,. .... , Effluent Gross REQUIREMENT 3 WPA op A v .____: '-" DA AVG- D 9 T pH SAMPLE ....... ...... 7.31 ...... 7.47 12 0 02130 GR MEASUREMENT 0040010 -. P- .6IT .: .--.Effluent Gross REQUIREMENT

.-.." ..MINIMUM ....._._*_..MAXIMUM " ' .Tw -ce e r Month-.?:.

Solids. total suspended 0.12 0.19 26 .<1.3 2.3 19 0 02130 24 MEASUREMENT 00530 10 ,PoWT 5.3 10.5 '..,-. 3 " " -? `6 Effluent Gross REQUIREM ......... " .Y .. .*: -ODAAV.. DALY. -TITO '.Flow. in conduit or thru SAMPLE 0006 ..... 0.101.treatment plant MEASUREMENT 000013 .........0 0101 N 5005010 PEFr .Ieq. Mon. 'Req. Mon. --..,Efiuent Gross MEQUIREMENT 300A AVG. * ._.SAMPLE MEASUREMENT

... -~~~~. " " .".. ..-."...I. .".".~~~~~~~~~~~~~~~~~.

..-....,.. *.. ..:,.. .-. ..... ... ...... ... :. ....-..:... ,:... ,: .: RPE REQUIREMENT.

SAMPLE-MEASUREMENT

___________

_ _ _ _ _ _ _ _ _ R Q I E E T -......_ _ _ _-_.. ........ -.. .,._._.' ._ : .. , ; ,. :- '.: ...:.. ..' SAMPLE MEASUREMENT A ...:.r. ..-y -__ __ __ __ __ __ RE ulRE -l.... "-- .: ....... _ _ _ _ _ _NALEEUE I certify under penalty of law that this document and aOt atadunchtns were prepard under my TELEPHONE DATE PANCIPAL 1XECUTIVE OPFtEr" Of supervao in accordance wth a system desgne to assure tha quafited pensonnel properly gather and evatute the intonniaton submitted.

Be on my mquhy oP the person or persons Benjamin P. Youman who manage the system. or those pemons directly responsible for gathering the intonnatbn.

the t,:7 01/2C213 informaton submitted is. to the best of my knowledge and betiel. true. accurate, and conplete.

I am IG RE OF P iCIPLE Plant Manager aware that there am significant penalties for submitting false tim0lomln.

including the possftty d EXECUTIVE OFFICER OR AREAUMB lime and inpisionent for knowing v~latbis.

AUTHORIZED AGENT CODE NM_/_COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfal 30 of 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 610107 AA trrnyFl:NV R.PIF:t I DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I 1LPMN4833E r- PERMIT NUMBE I C01-0 DISCHARGE NUMBER I MONITORING PERIOD MMIDDJYYYYL MMIDDIYYYY WWTP (FORMER ODIC)External Outfall* NO DISCHARGE FROMI 07/01/2013 I TOe 07/3112013 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ALYS TYPE sos total suspended

..................

3.0 3.5 19 0 02/30 24 Solds toalsusened MEASUREMENT 0 0 5 3 0 1 0 i --.P r r ... ............: ... ...: .. ..: * * " .." , ,m .l1 ...-.3 ..- .' ...,-.' ." ..." I : -_ -.-.00530 100 Effluent Gross REQUIREMENT

-,- .., ..___AAV_....

D '.X m -; *W.: T -rMot ...: Chromium.

hexavalent SAMPLE ..........

...... ......(as Cr) MEASUREMENT 500 0103210 P:.. PERMIT. -.1 .-. ,2-. " o '" i Effluent Gross R.QUIF.EMENW t , .... A , ... M%.Chromium, total SAMPLE ......(as Cr) MEASUREMENT 01034 10 "fERWp. ..2-Effluent Gross REQUIREMENT, ,.. ....._"' ,0A AVC -DAIy- .. ,- ..Copper. total SAMPLE ...........(as Cu) MEASUREMENT 500 0104210 .77 ... .. .-, ,a-y.Effluent Gross -REQUIREMENT , .: .. ...:. ... .:3DOPAAVG .QAJLYMX.

'" " Iron, total SAMPLE ............

..(as Fe) MEASUREMENT 500 Effluent Gross REQUIREMEN" ,, .'"- ..".... .., y --Lead. total SAMPLE .........

.......(as Pb) MEASUREMENT 500 0105110 ,.. r r -T ." Effluent Gross UElrEbtMENT , .-'."... J 3 A "DA"LYM " !'

D Nickel, total SAMPLE ........ .... .....(as Ni) MEASUREMENT Soo 0106710 '.. .. .... "- 1 2 Effluent Gross XREOiREMEIT

...A ...... .-. .-. , .., , .NAME/TILE I Cerfly unlder penalty oi law tral vids domument and all achmenls were prepared under my TELEPHONE DATE PINCIPAL EXECUTIVE OFFICER drectin or supeman in accodance with a system deslied to assure Mtt qualifl pedMOnal Benjamin P. Youman who manage the system. oat tose persons directly spomisible ta gathering the infomatia.

the 08/2612013 nWontatim submitted is. to the best di my krowledge and beliel, true, ancurate, and ctilmpeta.

I in SIamANURE

?)F'PRINCIPLE Plant Manager aware that them are sgnificant penalties for submiting false no'matin, the pos..ety of EXECUTIVE OFFICER OR AREA TnYEo oR MimT lee and biroraknnei for knowing v AUTHORIZED AGENT CODE NUMBER MM/DDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outfal 16 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11/62012 PAGE 1 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER CH1-8 I -DISCHARGE NUM-BER-ýMONITORING PERIOD MM/DDYYYY I MMDDJYYYY WWTP (FORMER 001C)External Outtall I NO DISCHARGE FROMI 07/01/2013 1 TOr 07/31/2013 I I I lByron, IL 61010 ATTN: Zoe CoxIENV SPEC ______ ____________________

PARAMETER QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER

-________

NO. OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Zinc, total SAMPLE ...... ...... 500 (as Zn) MEASUREMENT 0109210 , .,r -,.. " .Effluent Gross REQUIREMENT 3- .-.. ..__.-_.__- .AVG .... * .... GRABK.Flow, In conduit or thru SAMPLE treatment plant MEASUREMENT 0.024 0.041 3 0 01/01 CN 50=5O10 PEM IT " .'Mon......34-5005010............................................

....... ..-....................................

......Effluent Gross PREQUIREMENT..

36AAVG DAILY MX ".Wl.. -' "7 * , ....SAMPLE MEASUREMENT"REQUIREME.T_..

.SAMPLE MEASUREMENT

-r ps,. .. .. ... .....,. ... ,. 4 _______________REQUIREM

____________

SAMPLE MEASUREMENT

.... , .". ;, ' ,.. ......................................:--: SAMPLE MEASUREMENT REQUIREMENT

__________

_____ .<:. .-____SAMPLE MEASUREMENT

____R._ _;_ _ REQUIP........

._-_NAiEnlLE I certfy under penalty of law that this document and an attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervislon In accordance with a system desiged to assure am qualified personnel properly gather andl evalute th Irwrmadn submaxi. Based an my inquiy d it pme an or persans .'i Benjamin P. Youman who manage the syster. or those peasons directly respmsie for gathering the informatio n..4 08/t2013 information sutd Is. to the best of my knowledge and belef, true, accurate, and carmpete.

I am oIGNATE OF O PLEr.Plant Manager aware that Ute are sionificant penalties for sultting false Ifomnation, including the poasiity of EXECTIVE OFFICER OR N ERRA____an pre___d ______fine and ____ fu_ __nv_ AUTHORIZED AGENT COID NUMBER MM/DDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITfEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I 11.0048313 PERMIT NUMBER DOI-0 DISCHARGE NUMBER[ MONITORING PERIOD UMMW/YW I MMIDDIYYYY RADWASTE TREATMENT (FORMER 001 D)External Outfal* * *NO DISCHARGE M FROMI 07/01/2013 I TOI 07/31/2013 I I I Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE SAMPLE t..al ....d. 2.0 3.3 19 0 02/30 CP Solids. total suspended MEASUREMENT 0053010 Pe. M!T 'IT Rq..th COM0PO , " RE EN ... " .30DA.AVO " ., MX. ."~ .i! .!] le M p Effluent Gross REQUIREMENT , .AV""DA.L.

M , g. ..-.,- .. .Moth Flow, In conduit or thru SAMPLE 0.= 0.0m 3 .............

0 01/01 CN treatment plant MEASUREMENT 500501 0 FOOgjq.Mon 0e. Pmonp, gId -Oth C~1 Effluent Gross REQUIREMENT 3MDA AVG , ...SAMPLE MEASUREMENT PERMIT-.MREASUIREMENT

________SAMPLE MEASUREMENT P.RMrT .,________________

REQUIREMN91.11

_____ _____ _____ ____SAMPLE MEASUREMENT rER U".N- :'-." " K" .' ." "' ' "r:-SAMPLE MEASUREMENT SAMPLE MEASUREMENT NAMEnTITLE I cerfty under penalty of law that this document and all antachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUT1E OFFRCER of supevmsion accoadance with a system desg to assure that qualified personnel Iproperly gather and evakft the kdormalion submitted Based on my lnquibV o theMpersn perso s Or ,a.. 815 3700 08/26/2013 Benjamin P. Youmnan who manage fte Systaf Of d1060 pesons dwy esmsap=" for ft iwormaon, mte "*082/01 mlonr kailm submitted Is. to the best of my Io woledge and betel. true. acc rate, and complete.

I am SIGNA OF CIPLE :::;[ NUMBER Plant Manager aware hat them are sindca penalt for submbn false infoimtam.

inchrdrng the pobafity of EXEClTIVEO0 CER OR Ar MMIDD/YYYY.M fine and iprisltmoment for fatowing vlatiMo. AUTHORIZED AGENT 4 COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 6 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116=2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES]DISCHARGE MONITORING REPORT (DMR)PERMIrTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER (FORMER 001E)External Outfall 61010 I MONITORING PERIOD I MMIDDYYYY I1o4 MM/DDIYYYY I FROMF 07/01/2013 07/31/2013 I"NO DISCHARGE rll lI l-V PARAMETER 7><:ýQUANTITY OR LOADING-4 VALUE VALUE UNITS VALUE Solids, total suspended MSUMENT MEASUREMEN~j

.~ j,,,.,,,.., 053010 0 Effluent Gross REQUIREMENT F. ......Solids, total suspended 0053080 Other Treatment, Process Complete SAMPLE MEASUREMENT pEfwrr'30'l 00 dy%~RA5.i " " " i " 1 , .~~~~~. .. .b .. .. .... .... r .,. .....* -..-.. ..--. ..-. .Chromium.

hexavalent SAMPLE ........ 5...... ......0 (as Cr) MEASUREMENT 500 0103210 P I T .A..q. A.. " ".- "Effluent Gross REQU ...N.T -- .-_- .... AVG".DA-L.,"-

mg'LC- AVGa .. "." , Chromium, total SAMPLE ...... 500 (as Cr) MEASUREMENT 500 0103410 PERMIT ..*..,..*1*2-mt- *Effluent Gross REQUIREMENT " .".'... " " .30DA AVd DA[IYMX :_ -.., " ..-'Copper, tolal SAMPLE ......(as Cu) MEASUREMENT 500 0104210 PERMIT. EMIR. .I -- U 4A Effluent Gross 0REQUIREMENT

-,3Q" .; ____ _ " " "AAVQ. XD M".Iron, total SAMPLE .............

..........

500 (as Fe) MEASUREMENT 5__0104510 ." ., ,., ." "a"" Effluent Gross .REQUIREMENT

..t_____ ' .JI .'. ." , --" ."..i.*Lead, total SAMPLE ...... ...... 500 (a s P b ) M E A S U R E M E N T 5___ __ _0105110 'PEfIMIT1 VMS Effluent Gross ,."A'REQUIEMET

,, " " '__ _ " " .-jpAAVQ " DAILYM;X .m. ... a: ..II, under penalty o law that this document end all alactamnets were prepared under "'y TELEPHONE DATE PRINCIPAL EXECUTlVE OFRCF.R direction or superesmn tn accordance with a system designed to assure tha qualified personnel " I, B nop"o gather and evalute the Iomatin subrrited.

Based an my lnr of the peson o815 406-37 Benjamin P. Youran who manage the sem, or those persons duectV reprnsibe for gathering the Information.

Uhe information submitted is. to the best of my knowiedge and belef. tre. accurate.

and complete.

I ame iNATE OF P IPLE Plant Manager aware that mare are sificart penalties for sunlitting false information, ncludkg the posily of EXECUI1VE OFF ER OR NUMBER MM/DDIYYYY TWPOR CA PED fine and imprisonment for blaming vi__ a__ __s. AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow existed through this oulfall 2 of 31 days during the month.3. There was no discharge of Fire Protection drain water during the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMI'rEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvite, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTN: Zn Cnx/ENV SPEC DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER MONITORING PERIOD MMFY I I MMIDr Y STORMWATER (FORMER 001E)External Outfall* I

• NO DISCHARGE

--- ...! I FROMI 07/01/2013 I TO I 07/31/2013 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER V OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TYPE Nickel, total SAMPLE .(as Ni) MEASUREMENT 0106710 .,- r .2*E_,u _,._,or___

.-R.=,=,REME,,=,, _ __......__-_.,,,-

,: , .300AAV_. .. ...Y..... .Effluent Gross *-& "IRMN ..*AW PA MX _______ ______zinc, total SAMPLE ...... ......5So (as Zn) MEASUREMENT 0109210 ,.PER?41T,-

... ..m ,..

• mg",.-: ,'eal .Effluent Gross REQUIREMENT r -.-, _ ...oAAVG o* Wa 0-- "_,-' __" _ "_Row, in condluit or thru SAMPLJE...

reatmentndlat SUME 0.178 0.209 3 0 02/30 CN treatmnent ptant MEASUREMENT_____

__________

__________

500501 0 .o T Req. ,r,. ...Reg.,M_..* , .. Tc -4r' neq. ( OeqMoT.ýEffluent Gross RmQ umv E T .W, " a. .,-. __ _ -._.. .. .. .... ,...SAMPLE MEASUREMENT

_______________REQUIREMENT..*.--_____

____SAMPLE MEASUREMENT_____

!.PEl MIT -I_____________REQUIREiMEN

___ ___ __ ___ __SAMPLE MEASUREMENT

________ ____,.PEMR!REQUIREMENT

________________

_____ ____SAMPLE MEASUREMENT

!g, ..l.,. .-,,.. ,.. ., MEASUREMN

-NAMEnTTILE Icerituy under penalty of law that the documentand aM allttachmnents were prepared under my EEHOEDT PRINcPAL O=EU'iVE oFRCERditio of TELEPHONE DATErac wt yt dsge oasuedmqaife esne BenjaminYprepeity gather and evaMe he ntwmatinsauftated.

Based on my mqury of the person or p--oa j..j/~ 8151 4008/6/201

...manage ft heyste. th .e perso directly responsible for gathering the In-..mati..

lth e. ".i...sation autndted i. to the beg of my Mnwledge and befe. true. accurate.

and c:nplete.

em IGNA&fKEOF fIIPLE Plant Manager aware that there are algnftant penafties For eubdn" falea Intotmatlat Including fth possiblft of EXECUTIVE OFINCER OR ARESNMR TMDO PUE --fine end inipramoment tor knlowing violatiors.

AUTH4ORIZED AGENT coo NUBE MMIDDJYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments herm)1. No Closed Cooling System Drain Water was discharged this month.2. No Service Water System drain water was discharged this month.3. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning wastewater was discharged this month.EPA Formt 3320-1 (Rev 01/06) Previous editions may be used. 116/212 --PAGE 21 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)I IL0048313 I I 001-0 PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 I PERMIT NUMBER I DISCHARGE NUMBER I MONITORING PERIOD MWMMIDIIYYI MIWDDIYYYY DMR Mailing ZIP CODE: 61010 MAJOR (SUBR 01) CS COOLING SYSTEM SLOWDOWN External Outfall* NO DISCHARGE F ...FROM I 07/01/2013 I To I 07/31/2013 I L I I lATTN. Zoe Cox/ENV SPEC ___________________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS Ex ANALYSIS TYPE Temperature, water deg. SAMPLE ...........

...... ........94.2 15 0 01/01 CN Fahrenheit .MEAUREM.NT 00011 10 .... "" -: ' , C ' .: .- 'Effluent Gross REQUIREMENT "Mo-X J-0 pH SAMPLE ........ ..... 8.30 ...... 8.63 12 0 01/07 GR MEASUREMENT 0040010 U hf6~8S~I ~ ~ d~R Effluent Gross :REQUI1REMENT

---MINIMUM -MAXI'U ~SolidsSAMPLE

.......d ...... 42-0 42.0 19 0 01/30 GR MEASUREMENT 005301 .. -.' -n: .-Effluent Gross R IEQUIRK E -- '- , ,-W. ., ". ... .on: " A .---...O&Grease............

.........

1.4 <1.4 19 0 01/07 OR MEASUREMENT 005561 0 .; :..P4IT " ...." -".-l .20' " , m.... ..Effluent Gross R IIR lEI4T ., ..." .., 0DA AVG.-'" DAIl.YM "_.___'I -__" ____Chromium, total (as Cr) SAMPLE ...... ...... ...... ... ... 0.005 19 0 01/07 OR MEASUREMENT 0103410 ' ".0;2.'Effluent Gross REQ7JIREME.T " .._.o_.... ... "' ' " , ..---Copper, total (as Cu) SAMPLE ............

...... .. ..... 0.025 19 0 01/07 OR MEASUREMENT 0104210 o -r5E~MITr -..,-. .... *0.071 -*." Effluent Gross REQUIR"MENT

.77 V ... " .DALY, IAB-'- ..SAMPLE ,* ..........000 .21 0 007R Zinc, total (as Zn) MEASUREMENT 0008 0.02 19 0 01/07 OR 01092 1 0 3.. _ ..-:.. , ... : ..-. -T.., ..3.-....Effluent Gross R..M 1 .: -I --I 300AAVG -.DI LW P( --. NAMEI nerLE I leny under penalty of law that ft document and al attachments were prepared under my TELEPHONE DATE property gather and evalute the bItonnation submitted.

Based on my inquiy of the person or persons 1 Benjamin P. Youman who manage the system. or those persons drectly respornsibl 109 gathering Me information.

the 815 406-3700 08126/2013 inlomiation submnittd Is. to the of my Wkowtedge and belief. true. accurate, and complMet, I am SIGN#URE

___Plant Manager aware that there are significant penates Ar submiBEing alsa informatio.

incuding te poastat EXEUTIVEh1I=CER OR R ee fine and imprislonmrnt for Waniing violations.

AUHRZDAET CD UBRMM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Relfemree all attachments hem)1. Monitoring data for outfall 001-0 is Included on attachment.

EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/812012 PAGE 1 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMriTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

L 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, L 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 1L0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD I MM/DDJYYYY MMIDD/YYYY COOLING SYSTEM BLOWDOWN External Outfall* -NODISCHARGE I I FROM I 07/01/2013 I TOI 07/31/2013 k -i i QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX AOAFS TYPE Oxidants.

total residual SAMPLE. 0.04 19 0 01/07 GR MEASUREMENT Effluent Gross AEQUIRbI gT. .._ .___.___ .-.-.. .DT5 .. 9' I'.SAMPLE ...........

0 Priority pollutants total effluent MEASUREMENT

... 5 5000810 .PERMIT". -.Re" Effluent Gross ,REQUIRFME,?,,T

_*.".

• IL-. ..'-, ..X Flow, hi conduit or tltru SAMPLE PLM ~ l tloatmen clnt MEASUEE 22.48 32.58 3 .........

...... ...... 0 01/01 CN treatment plant MEASUREMENT 5010 -R "=_q.Effluent Gross -EURMN.ALY~

-.*. -- ~ .~';w Chlorine.

totalE ...... SOO MEASUREMENT________

5006010 -P#IT..Effluent Gross REQUIREMENT..

'-, .." ". ?.v... ."-." .' .5 ...Hydrazine SAMPLE .............

....MEASUREMENT 500 8131310 "..P Mr ", , , ..... ; .T .. ...- D l. --0.027 E ff lu e n t G r o s s R [E Q U IR E M EA N T .--" _"'_"_"_*

.. ... ." --D. A V G .... .....; -.' .-.. -in g.SAMPLE MEASUREMENT

______________REQUIREMENT_____

______ _____________

SAMPLE MEASUREMENT

• ..., ~~~~... .... ... ... .o ; " ..REQUIREMENr

--." .-.. ... i .. , .._, .

I cently under penalty a law hat i docun'a aa atcment ware prepared umy TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER *nectbi or In accordance with a system designed to assure that qualfed TersEDeAl BenjaminP.

ouman prtygather anld evaft te he IonmaIIoA submiUed.

Based al my inquiry of Me person or pe062ns,1504/-370 who manage tMe system. or those persons direcly respoisible for gathering the infamatui the ;A OEM 1540-300OW2013

'SG 81NURE OTJRNCIPLE Plant Manager Information subittedI, t thebesto f myawedge and -i EXrlUTIVaIE VCER OR AREA NUMBER MM/DD/YYYY TVIPMORPR~law

-aware that there are significant penalties for submittning false Information.

Incuding the posslbliy of..UM E tIDYY i f *ine and imodrionment for knowin violtions AUTHOR AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITITEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvile, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 610107nn ("nvilFNV .qPlF DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD MM/DDJYYYY I MMIDD/YYYY STORMWATER RUNOFF BASIN External Outfall""" NO DISCHARGE 5_ ...FROM I 0710112013 ITOI 07/31/2013 ATTN: Zoo Cox'ENV SPEC PARAMETER QUANTITY OR LOADING F r t VALUE VALUE UNITS VALUE SAMPLE ..... .......Solids. Total Suspended MEASUREMENT 00 10 .PERMI" ..... "'" Effluent Gross RIEUIREEN

"" Solids, Total Suspended MEAMPLE ............

......0053M ar -Other Treatment, Process PEFQUIM ET ptess __________

Complete ..~ ______Chromium, hexavalent SAMPLE ...........

......(as Cr) MEASUREMENT 010321 0 PEMlT .,.l ..., ....-Effluent Gross REQUIREM.NT

-Chromium, total SAMPLE ...... ......(as Cr) MEASUREMENT, 0103410 .I T...Effluent Gross "REQUIFRIkfIENT

_ __ _-_ .._-___copper. towal (as Cu)010421 0 Pfth rantI flrrc SAMPLE MEASUREMENT II WH I Iron. total SAMPLE I ..... ....(as Fe) MEASUREMENT

_ _ _ _______ _____0104510 77.7.- ER7MIT -Effluent Gross REQUIRIEMENT

______., _ __________

..____. .._ _w."_,___Lead, total SAMPLE .....................(as Pb) MEASUREMENT 01051 1 0 Pi4l

• i. ,, ,,,. 063 Effluent Gross REQUIREMENT

'I, 30DA AVG NAME(nT1LE I Certy under penalty of law that this document and al attachmants were prepared under.my PMINCIPAL EXECUTIVE OFFICER direction or supevision in accordsnce wit a system designed to assure that qualified peronnel properly gather and evaluto the Information submitted.

Based on my inquiry of the person or person Benjamin P. Youman who manage the system, or thos perss directly responsible for gathering the information, the inlornmtion submitted is, to the best of my knowledge and belet, true, accumate.

and complete.

I am SIGNAVRE Plant Manager aware that there are significant penalties for submitting false Inlonnation.

Including the pasltility of EXECUTIVE OR Mr, OR o M ___~m 1 ine and imprisionmrnt for knowing violations.

AUTHORIZED I, COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference oll attachments here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection or Service Water System Drain Water was discharged this month.3. No Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS' 4300 Winfield Road Warrenville, 1160555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfall* I*NO DISCHARGE

[ " 61010 MONITORING PERIOD MMIDDYYYY I MM/DD/YYYY FROM I 07/01/2013

]I Tol 07/31/2013 I-I Il lQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF YP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS O Nickel. total SAMPLE .............

500 (as Ni) MEASUREMENT 0106710 P.. .011. .Effluent Gross REQUIREMENT T____ ____

• ____ ~AAG AYMC____Zinc, total SAMPLE .............

50 (as Zn) MEASUREMENT 0109210 .07RMr ,..... * ...,. -"6. .... -...7 .,, -.. ' ; " 'Effluent Gross RRQUIREMENT..'-"-" ," 30DA A ." Oil and Grease SAMPLE ............

...... 00 MEASUREMENT 03511210 ..-..'...,. .15 20.. .,.6.. ... .....Effluent Gross RQUIREMENI , ...-.. :', " )OArAYC3 ' : AI.YL. MY : lrgn:'u-..

Flow, In conduit or thru SAMPLE 600 treanment plant MEASUREMENT 5005010 Rea Mo .Effluent Gross "REQUIREMENT " 3 .u)l:A A ". --" " ' ,*.SAMPLE MEASUREMENT REQUIREMENT

........ ,_,_..._ __....._"_" SAMPLE MEASUREMENT

.. .. .,.REOUIR M ENT -._,.,-.SAMPLE MEASUREMENT P*MT -- ....-..*..:. ... ._______________REQUIREMENT_____-

..______________

NAMFTPL"LE I ceOF ly under penally of law dust di documeant and attacments were preare under my TELEPHONE DATE PIFUNWAL EXE:CU11VE OFIFCF.R diection or supenrlson in accoidance withea sysim designed to assure tria qu alifed pmpeitygatherandevabAetheinfomationsubmitted.

Based on my 'quky of the person or persons 815 406-3700 Benjamin P. Youman who manage the system. or those persons dilrectlys responsibe fr gathenng the Infonnation.

the 026/2013 inloim~atin Is, to the best of my knowledge and belief. true, accurate, and complete.

Iam I GNA E OF NCIPLE Plant Manager aware at there are significant penafties for submitting false Information.

including me possutiy of EXE TIVE OFCER OR AREA NUMBER MMIDD/YYYY ow PRINTED tite and ilsiormeft for kflahla~ims.

AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewatir during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612012 PAGE 2 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 July 2013 Page 1 of 2 MONITORING DATA: CWBD CWBD Flow Rock River DATE Temperature mgd Flow deg F cfs 07/01/2013 83.1 18.27 24,600 07/02/2013 83.1 25.50 22,500 07/03/2013 82.4 21.44 20,700 07/04/2013 86.9 21.57 19_300 07/05/2013 86.9 20.88 18,000 07/06/2013 88.1 32.58 16,900 07/07/2013 90.2 19.23 15,800 07/08/2013 91.4 16.71 15,100 07/09/2013 92.0 25.87 14,300 07/10/2013 89.7 17.99 13,300 07/11/2013 89.7 23.51 12,100 07/12/2013 83.0 25.17 11,000 07/13/2013 84.5 31.08 10,200 07/14/2013 89.8 19.37 9,570 07/15/2013 92.2 18.13 9,080 07/16/2013 93.2 22.68 8,660 07/17/2013 93.6 20.35 8,190 07/18/2013 94.2 19.58 7,860 07/19/2013 94.2 20.38 7,440 07/20/2013 92.2 27.77 6,990 07/21/2013 88.7 21.79 6,770 07/22/2013 88.7 18.63 6,750 07/23/2013 86.9 26.72 6,730 07/24/2013 84.8 19.11 6,500 07/25/2013 84.7 24.83 6,390 07/26/2013 85.6 21.20 6,430 07/27/2013 84.2 27.37 6,690 07/28/2013 77.6 16.76 6,450 07/29/2013 79.6 25.69 6,200 07/30/2013 80.5 24.63 6,040 07/31/2013 83.1 21.99 5,970 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2013V3uly\July 2013 ATTACH01.docx ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 July 2013 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of July 2013.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 32.0 mg/L on 07/08/2013.

The CWBD TSS value was 42.0 mg/L on 07/08/2013.

5. Rock River flow for July 2013 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in July 2013. (Special Condition 15).K:\BYR_CH\.BYRON.DB\CIerk\Monthly Discharge Monitor Rpt\201 3UulyUuly 2013 ATTACH01.docx Byron Environmental Audit -Request for Additional Information Response Question #: HH-1 Category:

Human Health Statement of Question: Provide NPDES monthly discharge monitoring reports for the past five years.Response: The NPDES monthly discharge monitoring reports for all months of years 2008 through 2012 and January through July 2013 are provided.List Attachments Provided: 1. NPDES monthly discharge monitoring reports for January 1, 2013 through July 31, 2013.2. NPDES monthly discharge monitoring reports for January 1, 2012 through December 31,2012 3. NPDES monthly discharge monitoring reports for January 1, 2011 through December 31,2011 4. NPDES monthly discharge monitoring reports for January 1, 2010 through December 31,2010 5. NPDES monthly discharge monitoring reports for January 1, 2009 through December 31,2009 6. NPDES monthly discharge monitoring reports for January 1, 2008 through December 31,2008 Exeltn.Exelon Generation Company, LLC wwwexeloncorp.com Nuclear Byron Station 4450 North German Church Road Byron. It 61o1o-9794 February 24, 2012 LTR: BYRON 2012-0023 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276 Subject Byron Station Monthly Discharge Monitoring Report S In accordance with National Pollutant Discharge Elimination System (NPOES) Permit Number IL0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units I and 2. This report covers the period of January 1,2012 through January 31, 2012.Hf there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Th~~yJ. Tulon S~ice President B Nuclear Generating Station TJT/ZC/ca Attachments NATKINAL POLWLIANT DISCHARGE EJMIHATION SYSTEM (NPOES)-OOTE NA0UDR NMIMEE1sn Gmrm 00 LW Aý 4300 Wbih Road Wanuws.b LUN0G WGAUO 4450NOMGWW Sh~f Reed Dym% L W101 NmecLtan No 0 0-R REPORT p)Q --W4M r 3 M14 (hNAM 61010.2 10 .1VM O NO 000PAW NATK*AL POLUNTANT 0ISCHARIBE BJNAllONM SYSTEM (NPDES)mNXAin .wu1 m OWN RE I(DI PEVJFIE NAWADO NAM Emn Os'amn Ca. LLC ADMW 4300VsdWRoAd WaiOImbS L 406W PAIRYV yvan INdw Powo Ma WOCAM 44 M olShm Omum Chwc Wed@VIMn L 61010-I iunouw mooam KAM)61010 I -0sms I I AMIn I --.mm...m I~1 m I -!I -AL!- -- A I I IN l4 OiýnAi inwnA WAhlE (MA)NIrdt I-lllgm p-g I I mlsummm I Il q ITO I iWI -Ak I m _ _ _ m-I omwusi J I 0M11ID2 I... wo minmin-l -ill HAWK PCLUWANT D.SCHARGE hUMNAIMO SYTM (NPOES)-NO M -wI -D mummq~woam 61010-wAIMMAOIEn Nm boomstmWW C0.~ LL-DD m=VAWWAed WWOws LOWG UACKMJY3w ooiaar P 6Mm LWA7M 4M6OoO0mm

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0 ADý 43W VRW n Warwookfte5 0?LATO4AL POLLUTANT DISCHARGE EUMNA11ON SYSTEM (NPOES)mCAR~OOmawfp" L 3- 08"-lwfzcm NAlM I 61010 MOMFORMPEFOOD I FACWlY Bpwm OMa. Pow$ ~NOW IVv mWYYYY I LOGAION MW6 Peul "smm Clu" dt Road 0WmtU1 0WS2 DPWn L 61010 9* 1, NOclf ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 January 2012 Page 1 of 2 MONITORING DATA.-CWBD CWBD Fow Rock River DATE Temperature CW D Flow dog IF edt 01/01/2012 70.9 20.28 7,660 01102/2012 68.6 15.24 7,540 01/03/2012 68.8 20.60 6,650 01/04/2012 69.4 17.71 6,730 01/05/2012 69.4 19.70 6,830 01/06/2012 75.5 19.98 6,650 01/07/2012 75.5 23.83 6,570 01/06/2012 72.0 19.69 6,460 01/09/2012 69.0 17.46 6,420 01/10/2012 73.4 17.56 6,280 01/11/2012 74.6 18.69 6,150 01112/2012 74.6 19.77 6,120 01/13/2012 65.0 20.36 6,140 01/14/2012 65.0 22.71 5,830 01/15/2012 68.1 19.95 5,930 01/16/2012 72.2 12.10 5,970 01/17/2012 72.2 20.67 5,880 01/18/2012 66.5 16.30 6,280 01/19/2012 72.5 18.78 8,390 01/20/2012 65.0 15.92 7,390 01/21/2012 66.6 22.49 6,470 01/2212012 69.7 17.40 7,870 01/23=2012 75.0 14.19 9,620 01/24/2012 67.7 16.86 9,730 01/25/2012 66.0 18.11 9,130 01/26/2012 68.7 16.46 8,700 01/27/2012 68.7 18.01 8,420 01/28/2012 70.2 21.31 7,440 01/29/2012 66.5 18.58 6,750 01/30/2012 63.3 12.67 6,090 01/31/2012 76.5 17.91 5,840 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 ReportsJanuary\January 2012 ATTACHO1.doc I .I ATTACHMENT TO COOUNG SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 January 2012 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of January 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite was used this month. Bromine compounds were not used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month. The Rock River TSS value was 11.5 mg/1. on 01/02/2012.

The CWBD TSS value was 16.5 mg/L on 01/02/2012.

5. Rock River flow for January 2012 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in January 2012. (Special Condition 15).KABYRCI-\BYRON.DB\ICerk\MonthIy Discharge Monitor Rpt\2012 ReportsUanuary\anuary 2012 ATTACHO I.doc Exelokn Exelon Generation Company, LLC www.exeloncorp.com Nuclear Byron Station 4450 North German Church Road Byron, IL 61o0o-9794 March 21, 2012 LTR: BYRON 2012-0031 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency BOW CAS #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number IL0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of February 1, 2012 through February 29, 2012.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Plant Manager Byron Nuclear Generating Station BPY/ZC/ca Attachments PERWrlrEE NAWE/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FaC[LITV Byron Nuclear Power Station LOCATION 4450 North German Church Road NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)SCc-lARGE MOKC7 ORýG REPORT PtMR)OL0483O13 AO-.0 PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MM/DD/YYYY MM/DD/YYYV FROM 02/01/2012 TO 02/29/2012 VMR Mwfling ZEP CODE U 0O)(SUOR 01) CS 61010 DEMINERALIZER REGENERATE WASTE (001A)Eternal OutfDtA Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC _ _FREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX SM TYPE>_____ _<___ ANALYSIS Solids Total Suspended

............

...... ...... 2.2 2.4 19 0 01/30 08 MEASUREMENT 00530 1 0 PERMIT -15 30 Effluent Gross _________

________ 300A AVG DAILY MX mIoih COMP-8 Chromium, hexavalent SAMPLE ......5......0......0......(as Cr) MEASUREMENT 5_0 0103210 PERMIT -... ...1 .2 Effluent Gross RmJU jT _________

S30A AVG .A...Y M fill ____GRA Chromium, total SAMPLE ................

......0 (as Cr) MEASUREMENT Soo 0103,01 0 PERMI .. ..,r ., 2 Effluent Gross Rr__U____l_

$_ODA AVQ DAILY MX n_ _ Daky GRAS Copper, total SAMPLE ............

......(as Cu) MEASUREMENT

...... _ _ _01042 1 0 PERMIT-...-.

Effluent Gross RE=UIRiI, ., 300A AVG DALY W mL Daly GRAS Iron, total SAMPLE ......5......0......0............(as Fe) MEASUREMENT Soo 10451 10 PERMIT --.... 1 GRAB Effluent Gross -_ * .DAINlY MX ....._w*GRA Lead, Total SAMPLE ............

...... ......(as Pb) MEASUREMENT Soo 01051 1 0 PERMIT , ., .. .2 .4 Effluent Gross R__QU__EME_

_ 30DA AVG DAILY MX m__" Daw GRAB Nickel, total SAMPLE ...... ...... ......(as Ni) MEASUREMENT Soo 0106710 PERMIT -**.. * ... 1 2 Effluent Gross __ __ __ __O AVG DAILY MX 1 DeJ*v GRAB NAMEITTILE I cenity under penalty of law that this document and a3 altachmants were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER "tmctCon or superfiion in accordance with a system designed to assure that qualified personnel ,iropetty gather and evatute the information submitted.

Based on my inquiry of the person of persons~~40~7 Benjamin P. Youman who manage the system, or those persons directty responsibe for gathering the infoniatbon.

the 402112012 information submitted is. to the best ol my knowledge and babet. true, accurate, and conplete.

I am SIGNAI"RE OF PIIJ7ClPLE Plant Manager aware that there are significant penalties for submitting lalse intormation, including the possib.lty ot EXECUTIVE OFFICER OR AREA oi 0 r ne and impnsIonreent lor knowing violations.

AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference eal attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed 27 o0 29 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)

NAME/ADDRESSExe~on Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4460 North German Church Road Byron, IL 61010 CMR Wx-i!1nq ZEP CODE: (SUOA 01) CS 61010 PLEIT8313 N PERMIT NUMBER A01-O DISCHARGE NUMBER MONITORING PERIOD MMIDDrYYY I L MMIDDIYY DEMINERAU.ZER REGENERATE WASTE (091A)External Outfall*

• NO DISCHARGE j* ]FROMI 02/01/2012 I TOI 02/29/2012 ATTN: Zoo Cox/ENV SPEC ______ _____________________________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS T Zinc, Total SAMPLE ........................(as Zn) MEASUREMENT 500 010921 0 PERMIT ... ..1 2 Effluent Gross ___ ___ __ ___ 300A AVG DALY MX WrnL Daily GRAB Flow, in conduit or thru SAMPLE 0.08 0.2 3 0 01/01 treatment plant MEASUREMENT 5005010 PERSNT Req. Mon. Req. Mort.Effluent Gross REQUUERINT 30DA AVG DAILY "X COTIN SAMPLE MEASUREMENT SAMPLE MEASUREMENT PERMIT SAMPLE MEASUREMENT PERMIT SAMPLE MEASUREMENT PERMIT REQUSIR3Af SAMPLE MEASUREMENT PERMT NAMEMTLE I certify under penalty of law that this document and all attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFRCER direction or supentvsion in accordance with a system designed to assure that qualied personnel property gather and evalute the information submitted.

Based on my inquy of the person or persons , 8,5 3700 Benjamin P. Youman who manage the system, or those persons directly responsilge for gathering the information, the 03/21/12 infonnalio subydnted is. to the best of my and beelf, tree, accurate, and comp.ee. I am SIGN RE Ad PRINCIPLE

,.Plant Manager aware that there are significant penalties for submitting false information, including the possiblity of EXECUTIVE FFICER OR AREA NUMBER MM/DD/YYYY T OR PRITD mfine and impisionmment for knowing violations.

AUTHORIZED AGENT CODE NUMBER_ _______ ______COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 21

NAME/ADDRESS NAME Exelon Generation Co., LLC A0RRESS 4300 Winfie!d Road Warrenville, IL 60655-5701 FACILITV Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATI'rN. Znr Cnrr/F:NV

.*plFC.NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD RO[ MMIDDIYYYV MdDI/YYYY FRM02/01/2012 roI =229=120 DMR Mali~ng Z?~ CODE:=fAOR (SUOR 01) CS 61010 STP PLANT EFFLUENT (FORMER 001 B)Enternal Outfall* *

• NO DISCHARGE QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS .X TYPE BOD, 5-Day SAMPLE 26 ......<4.0 <4.0 19 0 02/30 24 (20 Deg. C) MEASUREMENT 02.2001 02 00310 1 0 PERMIT 5.3 10.S 30 6O Effluent Gross RQUIROEWFT 30DA AVG DAILYMX 300AAV- DAILYMX m.L TWiePeMov0 COMP24 SAMPLE ............

...... 7.28 ...... 7.43 12 0 02/30 GR MEASUREMENT I 004001 0 PERMIT ...... 6 9 Twice Effluent Gross IIW1R11iBIT

____ __ MINIM&UM MAXIMUM SU Per Month GRA3 Solids, total suspended SAMPLE 0 14 0.23 26 ...... 2.1 2.7 19 0 02/30 24 MEASUREMENT 0053010 PERITr 5.3 10.5 30 80 Effluenl Gross RREOUMINT 3ODA AVG DALYMX Old SODA AVG DAILY MX rnm Twee Per COMP24 Flow, in conduit or thru SAMPLE 0006 0.010 3 0.101.treatment plant MEASUREMENT

...... ...... ...... 0 01_01 __s o=010 PERMIT Feq. Mon. Req. Mort.Effluent Gross 30DA AVG DALY MX Ia ....... Doily CONTIN SAMPLE MEASUREMENT PERLIT SAMPLE MEASUREMENT PERW SAMPLE MEASUREMENT PERMIT REQUIREMENT NARME'TtLE I certify under penalty of law that ttis documnem and a3 attachments wete prepared under my TELEPHONE DATE PRINAPAL E5CUI1VE OFFtCER tMroCben Or superision in accordance with a system designed to assure that quaffied personnel Benjamin P. Youmnan who manage the system. oa those persons directly resposibe tor gathering the into n s P 15 406-3700 t3/21/2012 information subritted is. to the best ot my nowltedge and beret. true, accurate.

and comp'!te.

I am SIGNA,_ _ _ _ _ P_ _ __IPLE Plant Manager aware that there are significant penalties tor submig talse informartin, including the posstibly of EXECUTIVE OFFICER OR AREA TYE CH PstE fine and imoprsionment ftr knowing vioations.

AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 28 of 29 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 1i NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)PERMITTEE NAMEADDRESS k1.MS Exelori Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 CNR M1t!ltlno ZP CODE: (SUBR 01) CS 61010 L00483O13 PERMIT NUMBER C01-0 DISCHARGE NUMBER MONITORING PERIOD I MMJDD/YYYY I MMIDD/YYYY WWTP (FORMER ODIC)External Ouffell* *

• NO DISCHARGE

°FROMI 02/01/2012 ITOI 02/29/2012 AT TN: Zoo Cox/ENV SPEC FREQUENCY__

SAMPLE___QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETrER OF__AMPOF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE SAMPLE ............

...... ...... 4.2 5.1 19 0 02/30 24 Solids, total suspended MEASUREMENT 00300 ERI ..,. ... ....30 0063010 PERMIGoI 300A AVG D3L0 X mgiL Twice Per Month COMP24 Effluent Gross RUOCUIREUI

______A_ A________

_____ ________ ______Chromium, hexavalenI SAMPLE ............

...... ...... 500 (as Cr) MEASUREMENT I 010321 0 PERMIT ...... .. D .1 .2 Effluent Gross REUWJR1MEiT" 30OA AVG DALY MX OOID~ GRAB Chromium, total SAMPLE ............

...... ...... 500 (as Cr) MEASUREMENT 0103M 0 PERIMIT 2.. M.WI.

• 1 2 Effluent Gross RUI ....... 30DA AVG DALY MX g/L D...yDaiAy Copper, total SAMPLE ............

...... ...... 500 (as Cu) MEASUREMENT"r 0104210 PERMIT -.....,. -i 5 Effluent Gross REWREMET 30OA AVG DALY MX LDy GRAB Iron. total SAMPLE ........................(as Fe) MEASUREMENT 5__010451 0 PERMIT ... ....., 1 Effluent Gross REGQWRMB 1)4.. MXD ..W Lead, total SAMPLE ............

...... ...... 500 (as Pb) MEASUREMENT 0105110 PERMIT 2 .4 -..Da l2 .4 Effluent Gross REQUIREIENT 300_A AVG DALY MIX LD (3RAB Nickel, total SAMPLE ............

....... Soo (as Ni) MEASUREMENT I 0106710 PERMIT .. .... --D* 2 Effluent Gross I_-_ AVG DALY MX mg/L Doily GRAB AFIITLI ceriUfy under penalty oo law that this document and aD attachments were Prepared under my TELEPHONE DATE PRItNCIPAL EXECUTIVE OFFICER direction or supervision hi accordance witm a system designed to assure that personnel property gather and evalute the Iformation submitted.

Based on my inqury the person or persons 815 406-3700 Benjamin P. Youman who manage the system, or those persons directly for gathering the inf ,on. the 03212012 informt1ion submied is. to the best of my knowledge and DeOef, true, acCurate.

and complete I an SIGNii.jE 0W';PRINCIPLE

_ __I Plant Manager aware that them are significant penalties for submitting false informalion.

nftdauing the possiblty of EXECUTIVE OFFICER OR AREA NUMBER MM/DD/YYYY o- 1 fin'e and i 'npris io ntm ent for knowing vio a i n .A U H R D A E T C O D E TYPED op Rom AUTHORIZED AGENT 0o ___COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outfall 16 of 29 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/GM2012 PAGE 1 PERMITTEE NA;E/ADDRESS N flflE Exelon Generation Co., LLC4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)Col 0 PERMIT NUMBER DISCHARGE NUMBER MONrTORING PERIOD MM/DDOYYYW MM1DDNYYY FROM 02001/2012 TO 02129/2012 DMR ,alling MP CODE: (SUBR 01) CS 61010 WWTP (FORMER COIC)External Outfall** *NO DISCHARGE QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER I X OF SAMPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Zinc, total SAMPLE ........................

500 (as Zn) MEASUREMENT 0109210 PERMIT ....... 2 Effluent Gross ______ ______ 300A AVG DAILY Mk V" p GRAB Flownconduitorthru SAMPLE 0.023 0.034 3 ............

...... 01/01 CN treatment plant MEASUREMENT 50050 0 PERI Req. Mon. 300A Req. Mion. Da* CONTIN Effluent Gross I AVG DAILY MX ----SAMPLE MEASUREMENT SAMPLE MEASUREMEN E ___________

________"_____

SAMPLE MEASUREMENT PERMISAMPLE MEASUREMENT SAMPLE MEASUREMENT QIAMEfllTIIE cartl;'y under penarry ot tawe tna ttus document and an asacftrments were prepared under my TELEPHIONE DATE PRoN'CIPAL EXECUTIWE OFFRcER rtirection or supervrsin hraccordance wertl a system destgned to assure marl quafhedl personnel property gather and evalule the infotreatiop suhbmitted.

Based on my irqwryf t the peso or Benjamin P. Youman who Ianspe the system, or these petscns direotty responsibte for gatterrrg mer oiralc. th e SGNTUE , NIP, 03/1/12 Plant Manager aware that theret are significant penalties tar submnitting false inforrnation.

including the possibuily of EXECUTIVE OFFICER OR AREA NUMBER MMIDD/YYYY

___rJ ie and itmprhrhonment tor knowing vitlrni. AUTHORIZED AGENT CODE___COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01106) Previous editions may be used. ' ...1/6/2012 PAGE?2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)MvX)7CA ReFORCT (DMR)PERMITTEE NA/E/ADDRESS MA-AE Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCAliON 4450 North German Church Road Byron, IL 61010 ATrN: Zoe CoxIENV SPEC 0;19R [Veicfltn ZtP CODE: M~AJOR (SUBR 01) CS 61010 IL00M83¶3 PERMIT NUMBER I00¶0 DISCHARGE NUMBER I MONITORING PERIOD MMOD/DIYYYI MMIDDfYYYY RADWASTE (FORMER 001D)External Outfall°NODISCHARGE FROMI 02/01/2012 I Tol 02r29/2012 I R RQUANTITY OR LOADING QUANTITY OR CONCENTRATlON NO. FREQUENCY SAMPLE PARAMETER EX OF TMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS SAMPLE ............

...... ...... <0.5 <0.5 19 0 02f30 CP Solids, total suspended MEASUREMENT 00530 1 0 PERWMIT ... ..15 30 Effluent Gross _________E111 300___ OA AVG DAIY b4 MO& TI~ePrt~~

OO Fow, in conduit or thru SAMPLE 0.023 0.023 3 ..................

0 01/01 CN treatment plant MEASUREMENT 50050"10 PEMIT Req. Mont. 300A Req. Momt.Effluent Gross REQUIfREIT AVG DAILY MX WON Daily CONTIN SAMPLE MEASUREMENT PERIMIT REOUIRWIIII__II_

SAMPLE MEASUREMENT PERMIT SAMPLE MEASUREMENT PEWm SAMPLE MEASUREMENT PERMW SAMPLE MEASUREMENTr PERMIT NAME'TLE I centy under penalty of law that thits document and all attactMents were prepared under my TELEPHONE DATE PRD4CIPAL EXECUTIVE OFFICER erection or supenrision in accordance with a system designed to assuM that qualified personnel property gather and evalute the infomation submitted.

Based an my inquiry of the person or persons A /. .Benjamin P. Youman who manage the systern, or those persons drctly responsiv, f0 gahering me Information. G 815 406-3700 03121/2012 insotli~on subit'lted is. to the best of my knoa wedge and beliet, true. and complete.

I amN Plant Manager aware that there are signirtant penalties for subming false information.

including the possbitlty of EXECUTIVE O'FFICER OR AREAN TYPED oR aewla rine and imprnslonmenl for Knowing viotabors.

AUTHORIZED AGENT COE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 8 of 29 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1AI/2012 PAGE1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DSCRAG2 MCK170MSRW EP-CR (OIR)PERMITTEE NAM;EJADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, iL 60555-5701 FACILITY Byron Nuclear Power Station LOCATOMO 4450 North German Church Road Byron, IL 61010 I CL0048313 DISCHARGE NUMBER I PERMIT NUMBER MAJUOR (SUBR 01) CS STORMWATER (FORMER 001 E)External Outfall* -NO DISCHARGE Ex ...61010 MONITORING PERIOD MMIDDYYYY I MMDD/YYYY FROMI 02/01/2012 J TO 02o2212 ATTN: Zoe Coxl'ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE> < -1ANALYSIS SAMPLE ............

...... ...... 500 Solids, total suspended MEASUREMENT 00530 1 0 PERMIT s. 15 30 DALY Effluent Gross RErUIRIEMiT

... ..._ 30DA AVG MX tMgA. Wee*l _ GRAB SAMPLE ............

...... ...... 5.5 6.0 19 0 01/07 GR Solids, total suspended MEASUREMENT 0053080 PERMIT 30 100 Other Treatment, Process REQUIREMENT 30DA AVG DAILY MX mgl. Weekly GRAB Complete 1 Chromium, hexavalent SAMPLE .............

500 (as Cr) MEASUREMENT 0103210 PERMIT .2,'* ... ....1 2 Effluent Gross REOUWET _________

_1,__,_ 300A AVG DAILY MX MgIL Daly GRAB Chromium, total SAMPLE ............

...... ...... 500 (as Cr) MEASUREMENT 010341 0 PERMIT ....... 1 2 Effluent Gross R IIEWT _r 3110A AVG DALY MX mL Daily GRAB Copper, total SAMPLE ............

...... ...... 500 (as Cu) MEASUREMENT 0104210 PERMIT .5.. ........5 1 Effluent Gross RErOUREMDET 30OA AVG DAILY MX 0-.L Dally GRAB Iron, total SAMPLE ............

............

500 (as Fe) MEASUREMENT 0104510 PERMrl ...a... 1 Effluent Gross REoUIRIEMEN DAILY MX m___ Daffy GRAB3 Lead, total SAMPLE ...... ...... .(as Pb) MEASUREMENT I 0105110 PERMIT ........ .. .2 4 Effluent Gross RE.QUIltEMET 30DA AVG DAILY MX gL Daly GRAB NAMTLE I cettify under penalty of law that this doiument and an attachments were prepared<

under my TELEPHONE DATE PRAINCIPAL EXECUTIVE OFFRCER direction or supenrison in accordance with a system designed to assure mtm quatred personnel property gather and eva.'ute the mfomation submitted.

eased on my inquiry of the pemon or persons Benjamin P. Youman r/to manage the system, or those persons responsible for gathering the intormabion.

8e..06..0 03e21/2012 information submined is. to the best of my krowledge and belef, true. accurate, and complete.

I am SIGNATU'JRO01 INCIPLE Plant Manager aware that there are significant penaties for submit"tg false Information, icicluding the possbhiy of EXECUTIVE O-FICER OR AREA NUMBER MM/DD/YYYY TVP O PR e and irinsiosmemnt for knowing volaons. AUTHORIZED AGENT CODE NUMBER___M_/DD

____Y COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow existed through this outfall 0 of 29 days during the month.3. There was no flow from this outfall this month however Fire Protection drain water was discharged to this ouffall this month which requires TSS sampling.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)(NSCMA!GE M oTORi REPCORT (OMRi)PERMmr-EE NAME/ADDRESS NAME, Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IIL0048313 PERMIT NUMBER F_-E01-DISCHARGE NUMBER DMR MsI!'ng ZIP CODE: (SUBR 01) CS STORMWATER (FORMER 001 E)Exteral Outfall""

• NO DISCHARGE r 7 ...61010 MONITORING PERIOD f MMMDU/YYY MWM/DDYYY FROMI 02101/2012 IToi 02129/2012 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREUENCY SAMPLE PARAMETEROF P VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel, total SAMPLE ............

...... ...... 500 Jas Ni) MEASUREMENT 50 0106710 PERMIT ....1 2 Effluent Gross RMIREMENT, 30OA AVG DAILY M L D GRAB Zinc, total SAMPLE ......5......0......0......

tas Zn) MEASUREMENT 500 050921 0 PER3MT .e... 2 Effluent Gross ROUMtEM0 30AADAVO DALLY MW mI Daily GRAO Flow , in conduit or th ru SAM PLE ...... ............ Sao treatment plant MEASUREMENT Sam 0," ; PEROMT Req. Iort. FReq. Mort. Mgai/d Twic Per Month CONTM Effluent Gross REUIOREMENT 30DA AVE DAILYM_SAMPLE MEASUREMENT IERNIhIT SAMPLE MEASUREMENT PERMOT REQUIEMEN11111T

_ _ _ _ _ _ _ _ _ _ _SAMPLE MEASUREMENT PERMOT SAMPLE MEASUREMENT NMErnTLE I cerlity under penalty of law that this document and aD attachments were prepared under my TELEPHONE DATE PRIPCiPAL EXECUTIVE OFFICER directon or superrision in accordance with a system designed to assure thai Olailfled personnel p.roerly gather and evalute the ionotlation subriited.

Based on my Iwiry of the person or ersons 815 406-3700 Benjamin P. Youman tho manage the system, or those persons directly responsible fr gathering the inormation, the J11-1 U 81541/2012 infonation submitted is, to the best of my knowledge and betel, true, accurate and Complete.

lam SIGNATPI.

OF P"$NCIPLE0 Plant Manager aware that there are signiticant penalties for submitt false intomation, incuding the possibity o EXECUTIVE OFFICER OR AREA* Mc OR PIRME r lne and Imprisionment for knowing vioatios.

AUTHORIZED AGENT COENUMBER MMDDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning wastewater was discharged this month.2. Fire Protection, Service Water or Closed Cooling System drain water was discharged this month.3. There was no flow from this ouffall this month however Fire Protection drain water was discharged to this outfall this month which requires TSS sampling.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)(MSCHAR~ra MCK1CROK REPGRT {OMR)PERMITrEE NAE/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road 0L0048313 PERMIT NUMBER F -001-0 DISCHARGE NUMBER tOhlR Mr.King ZIP CODE: MAJOR (SUBR 01) CS COOLUNG SYSTEM BLOWDOWM External Outall 61010 MONITORING PERIOD MMIDDJYYY I I MM/DDIYYYY i!FROM I 02/01r2012 1 TOFl 02/29212 I* ' "NO DISCHARGE

= ...Byron, IL 61010 ATFN: Zoo Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER VALUE VALUE UNITS VALUE VLEAU UIS X OF TYSAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS Temperature, water deg. SAMPLE ............

...... ............

75.5 15 0 01/01 CN Fahrenheit MEASUREMENT 0001110 PERMT ..ql mT.N Effluent Gross R___U______

_,0 MAX___________

SAMPLE ............

...... 8.67 ...... 8.71 12 0 01/07 GR pH MEASUREMENT 00400 10 PERMIT S ..h.d6..R.Effluent Gross _ _ _ __ MAXMUM SU_ Wee"y GRAB SldttlsseddSAMPLE

...... ...... ...... ...... 4.6 4.6 19 0 01/3D GR Solids, total suspended MEASUREMENT 00530 1 0 PERrT .... Req. Mort Req. Mort Effluent Gross PAGUIWT liii 300A AVG DAILY MX Mo" GRAB Oil & Grease ASMPE ....... <1.4 <1.4 19 0 01107 GR MEASUREMENTI 0551 0Is 20 Effluent Gross REOUIR1 T 300A AVG DALLY W_ _n Wee"ly GRA_Chromium, total (as Cr) ...........

...... ............

cO.0021 19 0 01/07 GR MEASUREMENT Glowz I] a PERMIT,,,...

,. ., .. 02 GA Effluent Gross 14140.111E113UT ,QAYMX MIAg Weekly GA SAMPLE ...... ...... ...... ...... ...... 0.2 Copper, total (as Cu) MEASUREMENT 500 01042 10 PERMrr ... .........

0.071 Effluent Gross AIWJ1IREM"T DAILY UX ML Weekly GRAB Zinc, total (as Zn) SAMPLE ............

...... ...... 0.004 0.008 19 0 01/07 GR MEASUREMENT 0109210 PERhST .... .213 .433 Effluent Gross _ __,A AVI _____M__L Was_-y GRAB NAMc/TITLE Candy under penalty of law that this document and a9 attachments were prepared under my TELEPHONE DATE PRINCtPAL EXECLUIVE OFFICER direction or supevision n accordance with a system designed to assure that quaffied personnel propeen u gather and evalute the Information subm2tted.

Based on my Inquiry of the person of 815 406-3700 Benjamin P. Youman w1ho manage the system, or those persons dimrecty responsible tor gathering the infonration.

te 03t21/2012 information subm!tted is. to the best of my knowtedge and befief. true. accurate, and compWte. I an SIGN F OpINCIPLE

_I Plant Manager aware that there am significant penalties for submitting false information.

linckuatg the possititty of EXECUTIVE OfFICER OR AREA lweOR PMED line and imprisionmant for knowing vioations.

AUTHORIZED AGENT CODE NUMBER MMoO/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Monitoring data for outfall 001-0 is included on attachment.

EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITCRWO REPORT PERW.I-TEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701Byron Nuclear Power Station LOCATION 44,0 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER 0' MR M(zl!ng ZIP CODE: (SUBR 01) CS COOIUNG SYSTEM SLOWDOWNOutfall 61010 MONITORING PERIOD I MM/DD/YYYY I I MWIDDIYYYY I FROM I 02/01/2012 I TOI 02/29/2012"NODISCHARGE F °l I 1 !ATTN: Zoe Cox/FINV SPEC ______ _______________________________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMMER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE> <IANALYSIS TP Oxidants, total res;idual ESRMNSAMPLE

...... ...... ...... ...... .....So 340441 0 PEMI .....0o SAMPLE ...........

-5.0 Effluent _____ Gross__ ___________

D_____ ALY MX m9&R Wceldy GRA13 Pnority pollutants total effluent MEASUREMENT

...5000800 PE..IT, Req. Mom.. Req. Mon.Effluent Gross P4011,1111111011W DAILY MIX DALY G Flow, in conduit or thru SAMPLE Flw ncnu rtr APE18.15 26.31 3 ...... ... ... ...... 0 01/01 CH treatment plant MEASUREMENT 5000PERMIT Mon. Req. Mon " Dy CONTIN Effluent Gross REQUIRU1.4..1.WIT 300A AVG DAILY MX Cfhlorne, total residual SAMPLE ............

...... ............

0.03 19 0 01/07 GR MJEASUREMEN'T Effluent Gross RECUN:43BIgkT DAILY UX m90L Wee*l GRAB HydazneSAMPLE

...... ...... ...... ...... 5D0 Hydfrazine MEASUREMENT 0I313 1 0 PERMIT ... ... ..... ..011 .027 DailyWhen Effluent Gross ___I____IR__

_,_ 300A AVG DALY MX GRAB SAMPLE MEASUREMENT PERIMT SAMPLE MEASUREMENT PERMITr NAME/TITLE i cert./under p o ltscut and at attadmets were prepared u my PFNCIPPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure that quasfiai personneltTELEPHONE DATE property gather and evatute the information sutrlted.

Based on my iquity of the person or psons 03,2815 406-3700 Benjamin P. Youman who manage the system, or those persons directly responsitte tor gathering the winoum, SIGNhe OF I01NCIPLE12 infomation sutitted is. to the best Of my bowedg and beef. true, accurate, and comipeate.

I at I Plant Manaler aware that there are significant penalties (or submitting false tiformartion, Including the I t of EXEC E OF CER OR AREA NUMBER MM/DD/YYY 1wof PmiSm raie and imptisionment tor kinowmng violations.

AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)PERMITTEE NAME/ADDRESS 4AME Exelon Generat~on Co., LLC ADORESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road PLT048313 Nd PERMIT NUMBER D 02-0 DISCHARGE NUMBER UNIR Vtaeffng zz? CODE: (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfall*

• NO DISCHARGE IX '61010 MONITORING PERIOD MMJDD/YYYY L _ MMnDDJYYY FROM I 02101/2012 I TOl 02/29)2012 I Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE SAMPLE ........................

Solids, Total Suspended MEASUREMENT 0053010 PERMIT ..... 15 30 Effluent Gross __,IRIT 300A AVO DAILY a MgL Wee*ly GRAB SAMPLE ........................

Solids, Total Suspended MEASUREMENT 0053080 PER. ...... 30 100 Other Treatment.

Process "V D Y9L W* GoAw Complete _____ ____ .__G _____Chromium, hesavalent SAMPLE ............

...... ......(as Cr) MEASUREMENT" 0 PERlr .0............

..... ..011 .01 Effluent Gross 3, ___A AV@ DAILY #A mg9L 0 GRAB Chromium, total SAMPLE ............

...... ......(as Cr) MEASUREMENT 0TOW 10 F T..1 2 Effluent Gross _ _30DA AVG DAILY MU MI/L Daily GRAB Copper, total MO VE ............

...... ......(as Cu) MEASUREMENT 0104210 PE.......02

.041 Effluent Gross _ A A DAILY W m9L 01 GRAS Iron. total SAMPLE ...........

...... ......(as Fe) MEASUREMENT 0104510 PERM1T 0............

Effluent Gross R013REM5UfT DAILY LX __.____A Lead, total SAMPLE ............

...... ......(as Pb) MEASUREMENT I 01051 1 0 ......DA...063 A2W DY GRAB Effluent Gross ____i_____0_A__A___GIL___

_ 300A AVG DDALy GRA 4AM1"UTE I certify under penalty of law that this document and au attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFRCER lirection or supemision in accordance with a system designed to assure that qual~fed personnel property gather and evatute the infomation submitted.

Based on my of the person or persons "-.. 815 406-3700 Benjamin P. Youman who manage the system. or those persons alrectty responsie Ior gathering the information.

the 0312112012 inntoalkon submitted is. to the best of my knowledge and belet, true, accurate, and complete.

I am SIGNAVUPE IO PRINCIPLE Plant Manager aware that there are significant penalties for subnmtting false informatimn, including the poesity of EXECbIWE OFFICER OR AREAN tinm 0n PmmVeI 1fe and rnpnsionrmem for knowing violations.

AUTHORIZED AGENT CODE NUMBER MMDDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 116M2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DiSCHARGE MOX70RNG R~EPORT (lOMR)PERMITTEE NAME/ADDRESSExelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, I160555-5701 Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 A'TrW- 7n,. flrurIhJ'l/N SPF:C DMR Malirtg TIP CODE: (SUBR 01) CS 61010;L0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDIYM I MMIDDYY STORMWATER RUNOFF BASIN External Out/all I*

• NO DISCHARGE EKI FROM I 02/011/2012 I TOI 02/29=212 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel. total SAMPLE ........................(as Ni) MEASUREMENT 0106710 PWT -., .011 .176 Effluent Gross .,RAQU.IR

... 30OA AVG DAILY MX mWL Daily GRAS Zinc, total SAMPLE ............

......(as Zn) MEASUREMENT 01092 T 0 PERMT ......047 .26 Effluent Gross 30OA AVG DAILY MX .Dm GRAS SAMPLE Oil and Grease EA M E ...... ...... ...... ......MEASUREMENT 035821 O -... .15 20 When Effluent Gross REaUIRIIENT

.. ..DA AVG DALY MX MOIL GRAS Row, in conduit or thru SAMPLE......

...... ......treatment plant MEASUREMENT 500510 Req. Mon. Req. Mort. .d- When ESTIMA Effluent Gross ,EQUIAME 300A AVG DAILY MX _ ESTIM_SAMPLE MEASUREMENT PERMIT SAMPLE MEASUREMENT PERMIT SAMPLE MEASUREMENT-PERMIT NAEITTLE I certify under penalty of law that this document and a' attachments were prepared under my TELEPHONE DATE PRiCIPAL EXECUTIV OFRFR direction or supervision in accordance with a system designed to assure Mat quafried personnel property gather and evatutre the information submitted.

Based on my inquiry of the person or persons Benjamin P. Yournan who manage the system, or those perons drectly respensibe for gathering the information tre 815 40.3 03/21/2012 information submrtted is, to the best of my knowtedge and belel. true, accurate, and complete.

I am SIGN..IE C.frRINCIPLE Plant Manager aware that there are significant penalties for submitting false formation.

including the possbft of EXECUTIVE OFFICER OR AREAJ SORRm -tine and imprisionrment tor knowing violations.

AUTHORIZED AGENT ODNUMBER MMDDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewater dunng the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612012 PAGE 2 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 February 2012 Page 1 of 2 MONITORING DATA: CWBD Rock River DATE Temperature mgd Flow deg F cfs 02/01/2012 75.5 16.09 6,400 02/02/2012 67.3 17.45 6,970 02/03/2012 67.5 16.69 7,010 02/04/2012 69.6 26.31 6,950 02/05/2012 69.5 11.88 6,870 02/06/2012 67.7 19.48 6,800 02/07/2012 68.6 18.60 6,580 02/08/2012 64.5 14.24 6,460 02/09/2012 68.8 18.72 6,380 02/10/2012 68.8 20.01 6,240 02/11/2012 66.6 21.36 5,950 02/12/2012 73.0 11.51 6,260 02/13/2012 73.0 20.80 6,600 02/14/2012 66.7 17.60 6,450 02/15/2012 71.1 18.10 5,980 02/16/2012 71.1 17.07 5,900 02/17/2012 70.6 17.79 5,890 02/18/2012 70.5 22.73 5,770 02/19/2012 67.4 18.42 5,660 02/20/2012 67.4 15.50 5,540 02/21/2012 71.1 19.60 5,550 02/22/2012 72.5 15.94 5,510 02/23/2012 72.5 18.45 5,420 02/24/2012 68.8 18.86 5,650 02/25/2012 68.8 22.70 5,640 02/26/2012 71.8 18.55 5,510 02/27/2012 71.8 13.84 5,570 02/28/2012 67.0 19.60 5,570 02/29/2012 75.5 18.36 6,250 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\FebruaryWebruary 2012 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 February 2012 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of February 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite was used this month. Bromine compounds were not used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 29 of 29 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month. The Rock River TSS value was 3.5 mg/L on 02/06/2012.

The CWBD TSS value was 4.6 mg/L on 02/06/2012.

5. Rock River flow for February 2012 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in February 2012. (Special Condition 15).K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 ReportskFebruaryfebruary 2012 ATTACHOI.doc Exel n.Exelon Generation Company, LLC www.exeloncorp.com Nuclear Byron Station 4450 North German Church Road Byron, I161010-9794 April 19, 2012 LTR: BYRON 2012-0045 File: c2:09.04--1:3 1.10.0101 Illinois Environmental Protection Agency BOW CAS #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for SByron Station, Units 1 and 2. This report covers the period of March 1, 2012 through March 31, 2012.Pursuant to Byron Station's NPDES permit, the Station monitors the Total Suspended Solids (TSS) result for Outfall C01 (Wastewater Treatment Plant Effluent) twice per month.On March 10, 2012, the TSS composite sample result for Outfall C01 was 37.9 mg/L and the duplicate result showed 39.6 mg/L. Reanalysis of the remainder of the March 10, 2012 sample showed 34.3 mg/L and 33.7 mg/L for the duplicate.

Once the original analysis results indicated greater than 30 mg/L TSS, the Wastewater Treatment Plant (TR) was shutdown.On March 13, 2012, the TSS composite sample result for Ouffall C01 was 3.0 mg/L and the duplicate result was 2.5 mg/L.The elevated TSS of March 10, 2012, did not endanger health or the environment.

Byron Station has been reviewing potential causes of the elevated TSS at Outfall C01. The TR system uses two 30,000 gallon Collection Tanks to collect influent wastewater until enough water is collected to initiate the treatment process. In addition to the collection tanks, four settling ponds also collect influent wastewater for eventual TR processing.

On March 10, 2012 the influent wastewater being processed at TR consisted primarily of TR settling pond water.The TR settling pond water often presents a challenge to the TR treatment system specific to the removal of suspended solids. When processing TR settling pond water, additional operator attention is required to assure that the system performs as designed.Several actions are being taken to prevent this event from occurring in the future. These include: implementation of operating procedure changes and creation of a new chemistry department procedure to perform a filter test of TR effluent approximately every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> April 19, 2012 Byr Ltr 2012-0045 Page 2 whenever TR is processing water. This event and all actions associated with the event are captured in Byron Station's Corrective Action Program under Issue Report 1339223.It appears lack of recognition of poor water quality being processed by the Wastewater Treatment (TR) plant is the main cause of the elevated TSS value.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Benjmin MP.Youman Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments bcc: J. Gould -Environmental

-Cantera Z. Cox -. Chemistry

-Byron PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTN: 7nn Cns/I:NV NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 A01-0 PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MMDD/YYYY MM1DD/YYYY DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 DEMINERALIZER REGENERATE WASTE (001A)External Outfall*

• NO DISCHARGE FROMI 0310112012 ToI 0132o12 0 I I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids, Total Suspended SAMPLE ............

...... ...... 1.8 1.9 19 0 01/30 08 MEASUREMENT 005301 0 PERMIT- S i,,0..A AVG D3"Y CO Effluent Gross REQUIREMENT 3 , __20DA AVG DAILY MIX_._m_/LMonthlyMP-Chromium, hexavalent SAMPLE ............

...... ......(as Cr) MEASUREMENT 500 0103210 PERMIT 2 .. .. -. ..Effluent Gross REQUIREMENT

' 30DA AVG DAILY MX __LDiyGA.Chromium, total SAMPLE ............

...... ...... 500 (as Cr) MEASUREMENT I 0103410 PERMIT ........ ...... 1 2 mgL Daily GRAB Effluent Gross REQUIREMENT

"_3_DA AVG DAILY MX -....Copper, total SAMPLE ............

...... ...... 500 (as Cu) MEASUREMENT 0104210 PERMIT ..... -.5 1 mGRAB Effluent Gross REQUIREMENT

._30DA AVG DAILY MX Iron, total SAMPLE ........................

500 (as Fe) MEASUREMENT 010451 0 PERMIT ,.- .... -1.Dl G Effluent Gross REQUIREMENT

_ DAILY MX mg__ Daily GRAB Lead, Total SAMPLE ............

...... ...... 500 (as Pb) MEASUREMENT 0105110 PERMIT ... .... .2 .4 Effluent Gross REQUIREMENT 2_0DA_ AVG DAILY MX g/ Daily GRAB Nickel, total SAMPLE ........................

500 (as Ni) MEASUREMENT 0106710 PERMIT .21 2 Effluent Gross REQUIREM ENT "_ '"__" ...... " S30DA AVG DAILY MX g/L Daily GRAB NAMEF.JTLE I cetify under penalty of law that this document and all attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure that qualified personnel propefy gather and evalute the information submitted.

Based on my inquiry of the person or persons ? -C.... = 815 406-3700 Benjamin P. Yournan who manage the system. or those persons directly responsible for gathering the information, the 04119/2012 infonnatiom submitted is, to the best of my knowledge and belief. true. accurate, and complete.

I am SIGNATUS OF I.AINCIPLE Plant Manager aware that there are significant penalties for submitting false information.

including the possifbity of EXECUTIVE OFFICER OR AREAN-weD ot PrIED fio ne and imprisionment for knowing violations.

AUTHORIZED AGENT CODE NUMBER MM/DDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed 31 of 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Slation LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC IL0048313 PERMIT NUMBER I DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I A01-0 DISCHARGE NUMBER 1 I MONITORING PERIOD I MM/DD1YYYY I I MMfDD1YYYY DEMINERAUZER REGENERATE WASTE (O01A)External Outfall"NO DISCHARGE FROMI 03/01/2012 I TOI 03/3112012 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OE SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TYPE Zinc, Total SAMPLE 500 (as Zn) MEASUREMENT 500 010921 0 PERMIT .. .... M 2mg& aily GRA Effluent Gross REQUIREMENT.

"-"_'_

• 30OA AVG DAILY.MX mg__. DaiyGRA Flow, in conduit or thru SAMPLE Roi odi rtr APE 0.044 0.103 3 ........ ...... ...... 0 01101 CN treatment plant MEASUREMENT 500501 0 PERMIT Req. Mon. Req. Mon. Mgal/d Daily CONTIN Effluent Gross REQUIREMENT 30DA AVG DAILY MX a _SAMPLE MEASUREMENT PERMfT.REQUIREMENT " '_'_' "_""_"_" SAMPLE MEASUREMENT PERMIT REQUIREMENT

_____.,__.._._.._.

SAMPLE MEASUREMENT PERMIT REQUIREMENT

., SAMPLE MEASUREMENT PERMIT REQUIREMENT

"._-_._____._*

SAMPLE MEASUREMENT PERMIT REQUIREMENT

.'NAMETITLE I certify under penalty of law that this document and at attachments were prepared under my TELEPHONE DATE PRJNCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure that qualified personnel property gather and evalute the information submitted.

Based on my inquiry of the person or persons 4063I700 Benjamin P. Youman who manage the system, or those persons directly responsible for gathering the information, the 815 406-3700 04/19/2012 inlormation submitted is. to the best of my knowledge and betel, true. accurate.

and complete.

I am SIGNAVRE PRINCIPLE Plant Manager aware that there are significant penaltes tar submitting faLse information, including the possabUty of EXECUTIVE OFFICER OR AREA UMBon emme fine and imprisionment for knowing violations.

AUTHORIZED AGENT CODE NUMBERMM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/8/2012 PAGE 2 PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PL004r13 I E H B01-0 I PERMIT NUMBER I I DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR 61010 (SUBR 01)CS MONITORING PERIOD MMIDDIYYYY I MMIDDYYYY STP PLANT EFFLUENT (FORMER 001B)External Outfall-NO DISCHARGE FROMW 03/01/2012 l TO[03/31/2012 I I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE SOD. 5-Day SAMPLE BD -aSAPE <0.28 0.39 26 ...... <6.7 9.3 19 0 02/30 24 (20 Deg. C) MEASUREMENT 0031010 PERMIT 5.3 10;5 30 80 Effluent Gross REQUIREMENT 30DA AVG DAILY MX' b/. 30DA AVG DAILY MX mg-L TWce Per Month wM-,24 pH SAMPLE ............

...... 7.48 ...... 7.62 12 0 02/30 GR MEASUREMENT 00400 1 0 PERMIT 6 .....9....... 6 '.Effluent Gross REQUIREMENT

._MINIMUM MAXIMUM U Twice Per Month GRAB SAMPLE Solids, total suspended MEASUREMENT 0.12 0.13 26 ...... 2.8 3.2 19 0 02/30 24 00530 1 0 PERMIT 5.3 10.5 30 60.Effluent Gross REQUIREMENT 30DA AVG DAILYMX -d30DAAVG D0AILYMX Flow, in conduit or thru SAMPLE Fo .icodiortrSA PE0,006 0.011 3 ...... ...... ...... ...... 001101 CNI treatment plant MEASUREMENT 500501 0 PERMIT Req. Mon. Req. Mon.. ".." .'.. CONTIN Effluent Gross REQUIREMENT 30DA AVG ODALYMX ............

"..'SAMPLE MEASUREMENT PERMIT REQUIREMENT

.' "._"__ " SAMPLE MEASUREMENT PERMIT REQUIREMENT SAMPLE MEASUREMENT PERMIT REQUIREMENT

-NAMEMtMTLE I ceany under penalty of law that this document and all atlachments were prepared undet my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure thai qualiied personnel piroperty gather and evalute the inlormation submitted.

Based on my inquiry of the person or persons 8 467 Benjamin P. Youman who manage tMe system, or those persons directty responsible for gathenng the Information, the , 815 406-3700 04/19/2012 Intormation submitted is, to the best of my knowledge and belief, true, accurate, and complete.

I am SIGNAIWE U. rRINCIPLE Plant Manager aware that there are significant penalties for submitting false information, including the possibilty of EXECUTIVE OFFICER OR AREAPrm-r ' [n'e and imprisionment for knowing violations.

AUTHORIZED AGENT CODE NUMB MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 30 of 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/18/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 AT[N Zom, Corr/lNV ISPEC DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER F -C010 DISCHARGE NUMBER 7 MONITORING PERIOD MM/DD/YYYY I MM/DD/YYYY WWTP (FORMER 001C)External Outfall NODISCHARGE FROMI 03/0112012 TOI 03/31/2012 l ,I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids, total suspended SAMPLE ...... 14.7 39.6 19 1 02/30 24 MEASUREMENT 0053010 PERMIT .s 30. .. .. Twice-pe..r M ,.,. 15 30 Effluent Gross REQUIREMENT

• _______.30DA AVG DAILY , mol Twice-PerMonth .COP24 Chromium, hexavalent SAMPLE ...... 500 (as Cr) MEASUREMENT 0103210 PERMIT ..1 mDaly GRAB Effluent Gross REQUIREMENT

"__ .30DA AVG DAILY MX _ GRAB *Chromium, total SAMPLE ............

...... ...... 500 (as Cr) MEASUREMENT 010341 0 PERMIT 2.. 1y2 Effluent Gross REQUIREMENT

--ODA AVG,, DAILYMX ",Dal.R Copper, total SAMPLE 50...... S (as Cu) MEASUREMENT 0104210 PER ...... ...5 Effluent Gross REQUIREMENT

."3A AVG .DAILY MX_- mg&L. Daily GRAB.--Iran, total SAMPLE ...... 500 (as Fe) MEASUREMENT 010451 0 PERMIT .1 Daily GRAB Effluent Gross REQUIREMENT DAILY MX .GA Lead, total SAMPLE ...... 500 (as Pb) MEASUREMENT 0105110 PERMIT .. .. .... .2 .G4 Effluent Gross REQUIREMENT

"_-_-_._.

_0ODA AVG DAILY MX rgL Dai GRAB Nickel, total SAMPLE ...... 500 (as Ni) MEASUREMENT 0106710 PERMIT ...... .,. 1 2 mg1L Effluent Gross REQUIREMENT

"____"__ _____" ___ "" 30DA AVG DAILY MX m Daily .GR NAME/TITLE I certify under penalty of law that this document and all attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evalute the information submitted.

Based on my inquiry of the person or persons .815 406-3700 Benjamin P. Youman who manage the system, or those persons directly responsible for gathering the information.

the 04/19/2012 information submitted is. to the best ot my knowledge and belief, true. accurate.

and complete.

I am SIGP URF.,' PRINCIPLE Plant Manager aware that there are significant penalties for submitting false Information, including the possiblity of EXECUTIVE OFFICER OR AREA oE -ine and imptisionmant for knowing violations.

AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this ouffall 20 of 31 days during the month.3. See DMR cover letter for WWTP TSS exceedence details.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMrITEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY I MMfDDIYYYY WWTP (FORMER 001C)External Outfall* I *NO DISCHARGE "J FROMI 03/01/2012 I TOI 03031/2012 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Zinc, total SAMPLE ........................

500 (as Zn) MEASUREMENT 0109210 PERMIT ...... 1 2 Effluent Gross REQUIREMENT

' 30DA AVG DAILY MX( mg/L Daily GRAB Flow, in conduit or thru SAMPLE Ro.i odi rtr APE 0.015 0.030 3 .... ...........

...... 0 01/01 CN treatment plant MEASUREMENT 50050 1 0 PERMIT Req. Mon. Req. Mon. -" Effluent Gross REQUIREMENT 30DA AVG DAILY MX Mga/d Daily CONTIN SAMPLE MEASUREMENT PERMIT REQUIREMENT SAMPLE MEASUREMENT PERMIT REQUIREMENT-

,. ._._SAMPLE MEASUREMENT PERMIT REQUIREMENT

-. *_'_'-_._, SAMPLE MEASUREMENT PERMIT REQUIREMENT SAMPLE MEASUREMENT PERMIT REQUIREMENT NAMEMJITLE I ceaniy under penalty of law that this document and all attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECU1iVE OFFICER direction or supervision in accordance with a system designed to assure that qualified personnel pmpertygather anevalutethe nformationsubmittel.

Based on my inqur of the peron or persons,-Benjamin P. Youman rho manage the systema or those persons sirectly responsible for gathering the Information, the 8151"2R14ý 4 6R37L 04/19/2012 information subnmtlted is, to the best of my knowledge and belief, true, accurate, and complete.

I am SIGN RE PRINCIPLE Plant Manager aware that them are significant penalties for submitting false Information, including the possibillty of EXECUTIVE OFFICER OR AR UMB ED Oe P' eine and impesionment for knowing violations.

AUTHORIZED AGENT CODE ER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT-EE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER D01-0 DISCHARGE NUMBER MONITORING PERIOD MM/DD/YYYY I MMDD/YYYY RADWASTE TREATMENT (FORMER 001 D)External Outfall* *

• NO DISCHARGE G*I FROMI 03/0112012 1 TO 03/31/2012

! I Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC SFREQUENCY SML QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. OFRPNE PARAMETER

____________

__N. OF SAtPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids, total suspended SAMPLE ............

...... ...... <0.56 0.6 19 0 02/30 CP MEASUREMENT 005301 0 PERMIT. .. ........ -15 30 Effluent Gross REQUIREMENT 30AAVG LY MX Twice PerMoth COMPOS Flow, in conduit or thru SAMPLE FoicodiortrSAPE 0.023 0.024 3 ...... ...... ...... ...... 0 01101 CN treatment plant MEASUREMENT 500501 0 PERMIT Req. Mon. Req. Mon.. DMgald Da ,By. CONTIN Effluent Gross REQUIREMENT 30DA AVG DALY MX " ', _NTI SAMPLE MEASUREMENT PERMIT REQUIREMENT

'.SAMPLE MEASUREMENT PERMIT REQUIREMENT

....SAMPLE MEASUREMENT PERMIT REQUIREMENT

__._ _"_ _- _-SAMPLE MEASUREMENT PERMIT REQUIREMENT.

._"_.._.SAMPLE MEASUREMENT PERMIT 7_________________REQUIREM31ENT

______________

NAMFTImTLE I certify under penalty of law that this document and all attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evatute the information submitted.

Based on my inquiry of the person or persons 815 408-3700 Benjamin P. Youman who manage the system, or those persons directly responsible for gathering the information.

the IfGAV- 815 406-370 04/1912012 information submitted is. to the best of my knowledge and belief. true, accurate, and complete.

I am SIGNATU"j;F ,MINCIPLE Plant Manager aware that there are significant penalties for submitting false information.

including the possiwrtty of EXECU1 OFFICER OR AREA TVI.0 RPiEnaoie and Itmprisionment for knowing viotio.I AUTHORIZED AGENT CODE NUMBER MM/DDY_ _COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 10 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER I E01-0 I DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I DISCHARGE NUMBER MONITORING PERIOD MM/DD/YYYY MM/DD/YYYY STORMWATER (FORMER 001 E)External Outfall.". NO DISCHARGE i::i FROM Il 03/0112012 I TOl 03/31/2012 I I !ATTN: Zoe CoxIENV SPECFREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE SAMPLE ............

...... ......Solid, total suspended MEASUREMENT 500 005301 0 PERMIT , 9.. 1W 30 Effluent Gross ,tEQUIREMENT 3DAAVG DAILY MX SAMPLE ...... ...... 23.7 24.3 19 0 01/07 GR Solids, total suspended MEASUREMENT 0053080 PERMIT ..30 100 -m Other Treatment, Process REQUIREMENT 30DA AVG DAILYMX g" L Weekly GRAB Complete : *_-_.._*Chromium, hexavalent SAMPLE 50.(as Cr) MEASUREMENT 0103210 PERMIT ... ... D ..1 .2 Effluent Gross REQUIREMENT 300A AVG DAILY MX mg/L DeIty .GRAB Chromium, total SAMPLE ............

...... ...... 500 (as Cr) MEASUREMENT 01034 10 PERMIT 2 1 Da2 GRAB Effluent Gross REQUIREMENT 30DA AVG DAILY MX ._-Dy R Copper, total SAMPLE 500 (as Cu) MEASUREMENT 01042 1 0 PERMIT ... .., .Dail .5 GR Effluent Gross REQUIREMENT..

30DA AVG DAILY [a Vg. ..a.y .Iron, total SAMPLE ............

...... .500 (as Fe) MEASUREMENT 014.0.ERIT.

...... ...... mo/L Daily GRAB" Effluent Gross REQUIREMENT DAILY MX Lead, total SAMPLE ............

...... ...... 500 (as Pb) MEASUREMENT 01051 10 PERMIT ...... 4.... ' .;,. ' ..." .mg/L DaIly GRAB Effluent Gross REQUIREMENT

.__*_._._30DA AVG. DAILY MX -..I NAME/iT1-E I certily under penalty of law that this document andi a! attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure that qualified personnel propedy gather and evaltute the intonmation submitted.

Based on my inquiry of the person or persons Benjamin P. YouFan who manage the systema or thoy persons dryecty responsible for gathering bhe Informatiun.

these815d40.-3700 0411912012 information submitted is, to the best or my knowledge an belief. true. accurate.

and complete.

I am SIGN- uE PRINCIELE Plant Manager aware that there are significant penalties for submitting false inforraot including the possibility of EXE=M11E OFICER O0R AREA f'lS A mnB ine and imprisiocnamnt for kinowing vioatons.

AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Refenrence all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow existed through this outfall 2 of 31 days during the month.3. Flow is estimated due to replacement of installed totalizer duringq this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11W/212 PAGE 1I NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-O DISCHARGE NUMBER MONITORING PERIOD MM/DD/YYYY I MM/DD/YYYY STORMWATER (FORMER 001 E)External Outfall* *

• NO DISCHARGE

--' ...FROMI 03/01/2012

] TOI 03/31/2012 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETR VAU NT AUX OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Nickel, total SAMPLE ............

...... ...... Soo (as Ni) MEASUREMENT 0106710 PERMIT 2

• 1.2 Effluent Gross REQUIREMENT " _.._" *_ .30DA AVG DAILY MX .... Daily GRAB Zinc, total SAMPLE ...... ...... Soo (as Zn) MEASUREMENT 0109210 PERMIT ...2*... 1 * *2 Effluent Gross REQUIREMENT

"-30DA AVG DAILY.MX.

mg/L Daily GRAB Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT 0.125 0.125 3 0 02/30 ES 500501 0 PERMIT Req. Mon. Req. Mon.Effluent Gross REQUIREMENT 30DA AVG DALY MX Mgal/d f" Twice Per Month CONTIN SAMPLE MEASUREMENT PERMIT REQUIREMENT

". .SAMPLE MEASUREMENT PERMIT REQUIREMENT

..... .. _- ._."_..-SAMPLE MEASUREMENT PERMIT REQUIREMENT

._._"_"_"" SAMPLE MEASUREMENT PERMIT REQUIREMENT-

_ ' _.... ,_ _NAMEI1TTLE I certify under penalty of Law that this document and as attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure that qualified personnel property gather and evalute the infornation submitted.

Based on my inquiry of the person or persons Benjamin P. Youman who manage the system. or those persons directly responsible for gathering the Infornation.

the 46-3700 04/19/2012 information submitted is. to the best of my knowledge and belief, true, accurate, and complete.

I am SIGN A6, hE P [PRINCIPLE

__5_=Plant Manager aware that there are significant penalties for submitting false information, including the possiblity of EXECUTIVE OFFICER OR AREA UMB OR IMM lne and imprislonment for knowing violations.

AUTHORIZED AGENT C'OD NU ER MM/I)D/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning wastewater was discharged this month.2. Fire Protection drain water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD MM/DD/YYYY I MMIDDIYYYY DMR Mailing ZIP CODE: 61010 MAJOR (SUBR 01) CS COOLING SYSTEM SLOWDOWN External Outfall NODISCHARGE ED I n,,. FROM 1 TOFI 03/31/2012 I I WC/VWPI4U I! lI Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC _ FREUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Temperature, water deg. SAMPLE ............

...... ............

900 15 0 01/01 CN Fahrenheit MEASUREMENT

____ ___00011 1 0 PERMIT M....,, Req. Mon. ly Effluent Gross REQUIREMENT " '_" " O MX d F Dai CONTIN SAMPLE ............

...... 8.62 ...... 8.80 12 0 01/07 GR pH MEASUREMENT 0040010 PERMIT ,.6 ,. 9 Weely GRAB Effluent Gross REQUIREMENT

.." MINIMUM MAXIMUM Solids, total suspended SAMPLE ............

...... ...... 3.7 3.7 19 0 01/30 GR MEASUREMENT 00530 1 0 PERMIT ... Req. Mon. Req. Mon.Effluent Gross REQUIREMEN*'

• _._--_. 30DA AVG DAILY MX mo_., R Oil & Grease SAMPLE ............

...... ...... <1.4 <1.4 19 0 01/07 GR MEASUREMENT 00556 10 PERMIT ... 20 mgL Weekly "GRA5 Effluent Gross REQUIREMENT

-_ " 30DA AVG DAILY MX. .W yR Chromium, total (as Cr) SAMPLE ............

...... ............

<0.0021 19 0 01/07 GR MEASUREMENT 01034 1 0 PERMIT 0.... " 0.2 Effluent Gross REQUIREMENT DAILY MXWe Copper, total (as Cu) SAMPLE ............

...... ............

0.012 19 0 01/07 GR MEASUREMENT 01042 1 0 PERMIT.......

...., ..... ...,.. -0.071 m91I WeekGy Effluent Gross REQUIREMENT

..... " ___._. _* ._ _ .DAILY MX m " Wey R SAMPLE ...........

...... 0.003 0.005 19 0 01/07 GR Zinc, total (as Zn) MEASUREMENT 0109210 PERMIT ..... .213 .433 Effluent Gross REQUIREMENT

-3. AVG DAILY MX m,. W NAME/TITLE I certify under penalty of law that this document and asi attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision In accordance with a system designed to assure that qualified personnel property gather and evalute the informnation submitted.

Based on my inquiry at the person or personas 1 406-37d00 04/19201 Benjamin P. Youman who manage the system, or those persons directly responsible for gathering the information, the i4/1 01 information submitted is, to the best ot my knowledge and belief, true. accurate, and complete.

I am SIGN217REr PRINCIPLE Plant Manager aware that there are significant penalties tor submitting false informiation.

including the possib1ity of EX.QUJTIVE OFFICER OR AREA NUMBER MM/)D/YYYY TrPF.D OR PAIn-o fine and imprlslonment for knowing violations.

AUTHORIZED AGENT COD E COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmenta here)1. Monitoring data for outfall 001-0 is included on attachment.

2. Copper ion skids started on 3/5/12.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT'EE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: 61010 MAJOR (SUOR 01) CS COOLING SYSTEM BLOWDOWN External Outfall I *NO DISCHARGE EJ ...MONITORING PERIOD I MM/DU/YYYY I MMIDD/YYYY FROM I 03/01/2012 I TOI 03/31/2012 Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC ______ _____________________________________

PARAMETER QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX* OF TYPE____________

I______ _____ ______ __________

ANALYSIS Oxidants, total residual SAMPLE ...........

500 MEASUREMENT 340441 0 PERMIT" .... .05 , ~ ~ ~ m/ * , NYX" iJ"Weekly GRAS.Effluent Gross REQUIREMENT

_. , DAILY Mx Priority pollutants total effluent SAMPLE 500 MEASUREMENT

__________

________500081 0 PERMIT ..R... Req. eq. mg/L Weekly GRAB Effluent Gross REQUIREMENT' " DAILY.MX

• DAILY MX Flow, in conduit or Ihru SAMPLE FoicodiortrSAPE 17.81 25.48 3 ...... ... ... ...... 0 01/01 CN treatment plant MEASUREMENT 500501 0 PERMIT -Req. Mon. Req. Mon. ., Da...,, Effluent Gross REQUIREMENT 30DA AVG DAILY MK Mga/d ..Daily CONTIN Chlorine, total residual SAMPLE............

............

0.04 19 0 01/07 GR MEASUREMENT 500601 0 PERMIT .. 0. Week.l y-... oGRAB W0 Effluent Gross REQUIREMENT DAILY-MX m"'oL W l SAMPLE ....... 5 Hydrazine MEASUREMENT

..... 500 813131 0 PERMIT ...... .... : ., 0DalyWhn Effluent Gross REQUIREMENT 300A AVG DAILY MX " Discharging SAMPLE MEASUREMENT PERMIT REQUIREMENT

'___.__ _SAMPLE MEASUREMENT PERMIT_ REQUIRIMENT

• ._'_.NAME/1rTLE I cerly under penalty of 'w that MtRi documeut and ati attachments were prepared under my PRINCIPAL EXECUTIVE OFFICER rirection or supervision in accordance with a system designed to assure that qualified persornel TELEPHOTELEPHONE DATE propery gather and evatute the intonration submitted.

eased on my inquiry of the person or persons 815 406-3700 Benjamin P. Youman who manage the system, or those persons directly responsible for gathering the information.

the SiGN E 04/19/2012 information submitted is. to the best of my knowledge and beliel, true, accurate, and complate.

I am FF"CER ORNUBRERM Plant Manager aware that there are significant penalties for submitin~g false information.

includinhg the poss: fily of E I FIE R AE UBRM/DYY TYPOI PRINTED tine and irrtorisionment for knowing violations.

AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 1 002-0 I DISCHARGE NUMBER MONITORING PERIOD MM[DD/YYYY I MMLD STORMWATER RUNOFF BASIN External Outfall* *

• NO DISCHARGE FROM I 03/01/2012 TOI 03/31/2012 Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC _ UANTITY ORLOADING__UANTITYORCONCENTRATIONNO._FREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TYPE SAMPLE ............

..... ......Solids, Total Suspended MEASUREMENT 0053010 PERMIT ..- ... 15 30 Weekly. GRAB Effluent Gross REQUIREMENT

_ _ -" .. _ "_: 3ODA AVG DAILYMx, WeeMly SAMPLE ...........

Solids. Total Suspended MEASUREMENT 0053080. .10 0050 0PERMIIT .... :'....30 .100 : gLWeekly " GRAB Other Treatment, Process REQUIREMENT 30DA AVG DAILY MX mgIy Complete Chromium, hexavalent SAMPLE .............

......(as Cr) MEASUREMENT 01032 1 0 PERMIT ...... ,, ...... .011 .018: m101 Daily GRAB Effluent Gross REQUIREMENT

.__30DA AVG DAILY MX ay Chromium, total SAMPLE ...... ......(as Cr) MEASUREMENT 01034 1 0 PERMIT 2... ........ ..... 1 2 Effluent Gross REQUIREMENT 30- 0DA AVG DAILY MX mg/. Daily GRAB Copper, total SAMPLE ...... ......(as Cu) MEASUREMENT 01042 1 0 PERMIT ......*. .. ... .025 .041 RAa Effluent Gross REQUIREMENT " r ' '.

• 30DA'AVG.

DAILY MX mg/" Daly GRAB.Iron, total SAMPLE ...... ......(as Fe) MEASUREMENT 010451 0 PERMIT,,,,, ,,. ,..;, m., ., ' Daily Effluent Gross REQUIREMENT

_. ._ DAILY MX mg/, DGRAB Lead, total SAMPLE ........................(as Pb) MEASUREMENT 01051 1 0 PERMIT ..063- .298 Effluent Gross REQUIREMENT.

..T', 3ODA AVG DAILY MX mg/L. Daily GRAB NAMEJ1TTLE I cettily under penalty of law that this document and alt attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure that qualified personnel

___________/_.,_

properly gather and evalute the Information submitted.

Based on my inquiry of the person or persons 8 4-Benjamin P. Youman who manage the system. or those persons directly responsible tor gathering the information.

e 815 406-3700 04/19/2012 information submitted is. to the best of my knowledge and belief, true, accurate, and complete.

I Em SIGN E A rE9YRINCIPLE Plant Manager aware that there are significant penalties for submitting lalse information, including the possiblity of EXEdTVbFFCER OR AREAN BM Y TYPIED OR MN-,W fine and impnsionrnent for knowing violations.

AUTHORIZED AGENT CODE NUMBER MMDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITIEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, 1160555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 A'T-TN! Znn Crn/IFNV 5PFC IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfall NODISCHARGEr

.61010 MONITORING PERIOD MM/DD/YYYY I MM/DD/YYYY FROM I 03/01/2012 I ToI 03/31/2012 X FREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FSAMPLE PARAMETER

____ ___N. OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel, total SAMPLE ......(as Ni) MEASUREMENT 0106710 PERMIT ....,,,, ...011 .176 Effluent Gross REQUIREMENT

'_"_"_30DA AVG DAILY MX Daily GRAB Zinc, total SAMPLE (as Zn) MEASUREMENT 0109210 PERMIT ..... : .,. .... ,047 .26 Effluent Gross REQUIREMENT m9, __._- __ 0DA AVG DAILY MX .Daily GRAB.Oil and Grease SAMPLE ......MEASUREMENT 035821 0 PERMIT , ., ... ..15 20 When-Effluent Gross REQUIREMENT

"_______.

"_____" 30DA AVG -DAILY MX ..mg_ Discharging Row, in conduit or thru SAMPLE......

......treatment plant MEASUREMENT 500501 0 PERMIT Req. Mon. Req. Mon. Mld .'*" *"... When Effluent Gross REQUIREMENT 30DA AVG DAILY MX *

• Discharging E SAMPLE MEASUREMENT PERMIT .REQUIREMENT

-__ -, ,_ __,____, SAMPLE MEASUREMENT PERMIT REQUIREMENT

,_ , ;_. 1_ ._-_._,_,_"_,.

SAMPLE MEASUREMENT_

PERMIT___________REQUIREMENT

"_"__ __*_NAME/TTLE I certify under penalty of law that this document and all attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system designed to assure that qualified personnel

_____ __,_,_.__,,_,,__

properly gather and evalute the iaonnation submitted.

Based an my inquiry of the person ot persons E16370 Benjamin P. Youman who manage the system, or those persons directly responsible for gathering the information, the..,-,.-

815 0 04/1963012 information submitled is. to the best of my knowledge and belief, true. accurate, and complete.

I am SIGNAT=yk OPrNRINCIPLE Plant Manager aware that there are significant penalties for submitting faise infonnation, including the poss"by of EXECbnVEM)FFICER OR AREA NUMBER MM/DD/YYYY TVPM Oine and imprrsionment for knowing violations.

AUTHORIZED AGENT CODE N ER __________

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/0/2012 PAGE 2 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit 1L0048313 March 2012 Page 1 of 2 MONITORING DATA: WBD CRock River DATE Temperature mgd Flow deg F cfs 03/01/2012 75.5 17.87 7,670 03/02/2012 71.0 17.98 8,190 03/03/2012 69.7 22.50 8,490 03/04/2012 68.0 19.36 8,390 03/05/2012 63.6 15.90 8,220 03/06/2012 79.0 20.02 8,030 03/07/2012 82.1 16.06 8,200 03/08/2012 82.1 16.78 8,520 03/09/2012 70.9 18.45 8,800 03/10/2012 73.9 25.48 8,900 03/11/2012 73.9 21.19 8,870 03/12/2012 70.9 10.79 9,250 03/13/2012 76.4 16.86 10,700 03/14/2012 79.0 15.93 10,700 03/15/2012 83.7 17.01 10,400 03/16/2012 83.0 18.66 9,890 03/17/2012 88.0 17.51 9,410 03/18/2012 88.0 15.36 9,110 03/19/2012 90.0 16.78 8,920 03/20/2012 90.0 18.17 8,800 03/21/2012 87.7 14.75 8,530 03/22/2012 89.3 17.54 8,430 03/23/2012 88.1 18.47 8,600 03/24/2012 83.3 20.42 8,620 03/25/2012 85.3 17.03 8,520 03/26/2012 85.3 13.28 8,190 03/27/2012 77.0 18.75 8,200 03/28/2012 87.0 15.26 7,910 03/29/2012 81.2 19.92 7,610 03/30/2012 77.2 15.30 7,710 03/31/2012 77.2 22.79. 7,730 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\March\March 2012 ATTACH01.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 March 2012 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of March 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite was used this month. Bromine compounds were not used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this ouffall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month. The Rock River TSS value was 20.8 mg/L on 03/12/2012.

The CWBD TSS value was 3.7 mg/L on 03/12/2012.

5. Rock River flow for March 2012 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in March 2012. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\March\March 2012 ATTACHO1.doc Exelon.Exelo' Generation Company, LLC www.exeloncorpcom Byron Station 445o North German Church Road Byror, IL 61010-9794 May 21, 2012 LTR: BYRON 2011-0059 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number IL004831 3, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of April 1, 2012 through April 30, 2012.On 4125/2012 at 18:30 hours the Unit 2 Natural Draft Cooling Tower (NDCT) basin exhibited a wave-type flow pattern that caused cooling tower water to overflow from the tower and flow into the storm water ditch located on the east side of German Church Road. The wave-type flow pattern is believed to have been caused when the flow through the NDCT had to be re-configured due to a riser pipe break. The broken riser pipe was bypassed so repairs could be made.The cooling tower basin overflow water flowed north in the storm water ditch and entered Woodland Creek via storm water Outfall 003, East Station Area Runoff. The estimated duration of the overflow is 30.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> at a flow rate of approximately 25 gallons per minute resulting in an estimated 46,100 gallons of cooling tower water flowing through Outfall 003. Analysis results of a sample of the cooling tower water obtained prior to entering the storm water ditch are summarized in the following table: S pH Copper (mgL) I Zinc (mgL) Chromium (mg/L)8.75 0.011 0.007 <0.0021 Byron Station Operators took immediate measures to lower the cooling tower water level in the basin of the NDCT to try to mitigate the effects of the wave-type flow pattern and reduce the flow of water from the basin. Sandbags were also installed to stop the flow of cooling tower water to the storm water ditch.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Benjamin P. Youman Plant Manager Byron Nuclear Generating Station SBPY/ZC/eh Attachments bcc: Jennifer Gould -Environmental

-Cantera (electronic)

Zoe Cox -Environmental

-Byron NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMI"TEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfitld Rr dr Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313.PERMIT NUMBER , A01-0 0!SCHAIOGENUMl IlO MONITORING PERIOD MMIDD/YYYY I I MMDDYYYY DEMINERALIZER REGENERATE WASTE (001A)External Outfall*"

• NO DISCHARGE

[j ...FROMI 04/01/2012 TOI 04/30/2012 I i lATTN: Zoo Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Solids.Total Suspended SAMPLE ...... <0.92 1.1 19 0 01/30 08 MEASUREMENT 0053010 PERMIT -,.5 3 Effluent Gross REQUIREMENT

• _ _"

• 30DA AVG DAILY MX. * .......Chromium, hexavalent SAMPLE ....... .,..,. .O (as Cr) MEASUREMENT 500 0103210 PERMIT ---.1 .2 ; 7_____________________

______ igil.Daily GA Effluent Gross REQUIREMENT

":_"__. -_".30DAAVG DAILY MX " mg/__" ' _ ._.Chromium, total SAMPLE .... ...........(as Cr) MEASUREMENT 500 0103410 -PERMIT ,. ..I.. " ..... .-2 Effluent Gross REQUIREMENT " : .o , -..... 30DA AVG" DAY MX g/I Daily GRAB Copper, total SAMPLE ...(as Cu) MEASUREMENT 500 0104210 .PERMIT ". "."*. "" : " '" , .5 1 Effluent Gros REQUIREMENT

• __,.....30OA AVG DAILY MX mg/I. Daily GRAB Iron, total SAMPLE ............

500 (as Fe) MEASUREMENT 0104510 PERMIT ..1 ..Effluent Gross REQUIREMENT

...._'... --___. DAILY MX GRAD Lead. Total SAMPLE ..... 500 (as Pb) MEASUREMENT 500 0105110 PERMIT -4 .." .A VaL- " GA Effluent Gross REQUIREMENT q 30.DA AVG. DAILY.MX ..GRAB Nickel, total SAMPLE ...... 1 (as Ni) MEASUREMENT Soo 0106710 PERMIT -.-1 2 .Effluent Gross REQUIREMENT

.' _ "_ .. -" : ." :30DA AVG:,- DAILY MX. _g/_ " GR. ": NAME/TTTLE I certify under penaty of taw that this document and ae attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUniVE OFFICER direction or supervision in accordance with a system designed to sure that quaified personeL O BenjaminP.

Youman w lan d evter t theInrmont sd. my kqonyeof the pero.fersons 815 406-3700 05/21/2012 Benjamin P. Youman who manage the systemt. or those persons directly responsible tor gathering the information, the 0/121 Information subrmited Is. to the boes of my knowledge and belief. true. accurate.

and complete.

I am 916NAT&RE OF PRINCIPLE Plant Manager aware that there are sigtificent penalties or submitting false Information.

bicudng the possiblty of EXECUTIVE OFFICER OR ARMA'ryD DR Punmo fne and lmprlslmoment lor knowing violatons.

AUTHORIZED AGENT CODE NUMBER MIDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference ell attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed 27 of 30 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL004831 3 I PERMIT NUMBER I A01-0 N I DISCHARGEF Nli.MEtE .MONITORING PERIOD UMMDDIYYYY I I MMIDOJYYYY DEMINERAIZER REGENERATE WASTE (001A)External Outfall* *

• NO DISCHARGE

• ]FROMI 04/01/2012 I TOI 04/30/2012 l I I I ATTN: Zoo Cox1ENV SPEC ______________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Zinc, Total SAMPLE ....... 500 (as Zn) MEASUREMENT 0109210 PERMIT --. ..... 1 G2 Effluent Gross REQUIREMENTI 30DA AVG. DAILY MX. GRA Flow, In conduit or thru SAMPLE treatment plant MEASUREMENT 50050 10 PERMIT Req. Mon. Req. Mon. M,-. --l/ ." Daily CONTiN Effluent Gross REQUIREMENT 30DA AVG DALYM....

• M.. -" .-i .. -SAMPLE MEASUREMENT REQUIREMENT

.______...

• _ _ ... .... .. " SAMPLE MEASUREMENT PERMIT, ..." .I REQUIREMEN4T

... " ." :... " " ___:"_' __....SAMPLE MEASUREMENT PERMI, r .". ' -. .______________REQUIREMENT_____________

_____ __ _____________

SAMPLE MEASUREMENT PERMIT REQUIREMENT

_ .I .- ........ "-. ..,_..._._

.-" SAMPLE MEASUREMENT PER MIT ., ." * -', " " " -".._ .. .REQUIREMENT

."T,. ' *: -, .. ..." "" " ...-'NAAIiFITTLE I ceftt under penalty of law thai thO document and all wars Prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supenrfion in accordance wi a system des4gned to smsue that qualified Personnel property gather and evalute the informalton subnllfted.

Based on my inquiry of the person or perons 815Z7/..,..."--81 406-3700 Benjamin P. Youman who manage the system, or those persons directly responsible for gathering the nfomntlon, tire "-,,,O' ,WI,,-,,, ,.- -05/21/2012 Informnatiorn submitted Is, to the best of my loiuledge arid belet, true. accurate.

and complete.

I amir SG TUly OF PRINCIPLE Plant Manager aware that there are significant penalties for submitting false biformation, tIchxdrig the possibliy of EXECUTE OFFICER OR AREA 16om 0fT fine andr impsiorment for knowing viojaton.

AUTHORIZED AGENT CODE NUMBER MM/_D/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 2 NATIONAL POLLUTANT DISO GE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)0 61010 PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: zoe CoxdENV APEC DMR Mailing ZIP CODE: MAJOR (SU BR 01) CS IL0048313 I PERMIT NUMBER E1101-0 DISCHARGE NUMBER MM/DD/Y`YYY SfLWkI MM/DOIYYYY STP PLANT EFFLUENT (FORMER 001B)Externai Outiaii' "* NO DISCHARGE L °FROMI 04/01/2012 TOI 04/30/2012 1 z !QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREUENCY SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE BOO, 5-Oay SAMPLE MEASUREMENT

.54 0.85 26 <11 17.0 19 0 02/30 24 0031010 __ _ REQUREMENT 5ODA AVG5 DA0L M.__________

(2W .g ) MEASUEMEN 0030. E.Effluent Gross REQUIREMENT

.300A AVG' ,DAILY MX --DA AVG DAILY MX -Twice Per Month COMP24-SAME ...... 7.63 7.64 12 0 02/30 GR 004001 0 PERMIT -.."" 6" 9-Effluent Gross REQUIREMENT

.______-_

MINIMUM .-- MAXIMUM. SU .,wce Per Mo-th GRAB Solids. total suspended SAMPLE MEASUREMENT 011 0.13 26 1.8 2.5 19 0 02/30 24 0053010 'PERMIT 5.3 -10.5 .... SO Effluent Gross REQUIREMENT 30DA. AVG .-DAILY MX " b0d SODA'AVG D"OLy MX, "g/_. Twice Per Month, COMP24 Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT 0.005 0.007 3 ...... 0 01/01 CN 500501 0 PERMIT Req. Mon. Req. Mon.Effluent Gross REQUIREMENT 30SDA AVG " DAILY MX M.gad .-" Daily .CONTI N SAMPLE MEASUREMENT PERMIT ,REQUIREMENT

.*_._______"__.....__

SAMPLE MEASUREMENT PERMIT .REQUIREMENT.

_ __._". __.. .___ T ""________

SAMPLE MEASUREMENT PERMIT' ..7777 .-----*REQUIREMENT a __"__"__._ , -NAME/TITLE I cer* under penalty of law that Oft document and all ahttachents were prepared under my TELEPHONE PRINCIPAL EXECUTIVE OFFICER dirction or supervision n accodance with a system desWd to assure that qualied personneT DATE property gather evahfle the ',tonrmati subttmited.

Based on my Inquiry of th person oi persons 815 406-3700 Benjamin P. Youman who manage te System, or thofm person direc resp for gathe" the Informatlon.

fthe 81 4-005/21/2012 informaion submitted Is, to the best of my Imowlede and behiel, tue. bcjurate.

and complete.

I am SIGN I-RE PRINCIPLE Plant Manager aware that there am sWltant penalties lot submtttini fal , t P EXEioTtVEnFFICER OR AREA N B MMJDNof Plant Manager fine and Imrisalorirnent for knowing; vloailaoris.

FIE R AE UBRM1~YY TMED on prmo _____ _________________________.AUTHORIZED AGENT CODE NMRM_COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outlall 29 of 30 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT'EE NAME/ADDRESS NAME Exelon Generation Co., LLC-DRE"~ 430 a; 'e R oa d Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 DMR Malling ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 I EROLdIT NUMBEROC r- C01-0 I I'IOVLARf 11 IE f MONITORING PERIOD MM/DD/YYYY I I MM/DD/YYYY WWTP (FORMER 001C)External Outfall* **NO DISCHARGE EJ I -I I FROMI 04/01/2012 I TOI 04/30/2012 I i !i w I I ATTN: Zoe Cox/ENV SPECFREUENC_

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids totalsuspended...

... 5.7 8.2 19 0 02/30 24 Solds toalsusened MEASUREMENT 00530 10 PRI 53 Effluent Gross REQUIREMENT.E T" '-. ... ."30DA1AVG. "AILY MX mg/L.. .TwIce Per Mon. h COMP24 Chromium, hexavalent SAMPLE ................

5 (as Cr) MEASUREMENT 500 0103210 PERMIT , ..-.1 .2 .Effluent Gross REQUIREMENT

"-,"ad__.-

.__ :.,__ SDAAVG DAIYMX -GRA"" Chromium, total SAMPLE ...... ......(as Cr) MEASUREMENT 500 0103410 PERMIT. 2. .****. ..0...1 *Effluent Gross 'REQUIREMENT

_______- _ "_._.. ___ '.. .__ ". __"_"_-. ." ODA AVG .DALYMX GRAB Copper, total SAMPLE 5...00 (as Cu) MEASUREMENT 0104210 PERMITW,-

...., -.5 1 REQUIREMENT-Da.5 GRAB Effluent Gross REQUIREMEN" ..30OA AVG DAILY-Mx InQ/L D Iron, total SAMPLE ...... 500 (as Fe) MEASUREMENT 01045 10 PERMIT ... ..D.al --RA 1'__-_,,-_.___"____

_"__'. ____ DAILY " "mgfL Daly GRAB-Effluent Gross REQUIREMENT

-DAILY MX. ._ _ -___.,_Lead. total SAMPLE ...... S,... oo (as Pb) MEASUREMENT 010511 0 -. PERMIT ....4.. -.v... ....2"..4g/L DGRAB Effluent Gross REQUIREMENT

.__ ______ 30DA AVG .'DAILY MX " " m y- ,G Nickel, total SAMPLE ...... Soo..... 5 (as Ni) MEASUREMENT 0106710 PERMIT ,. ' 2- mg. .Daily GRAB Effluent Gross REQUIREMENT

-" _- _._" "_ .... -30DA AVG DAILYMW _ _ __ _NAMEITTLI.E I certify under penalty of law thai this document and al attactvments were prepared under my TELEPHONE DATE PRINCIPAL EXECIllVE OFFICER jreakiy or supenrisi in accondance with a sysem designed to assure th qualitted pesonnel prope rty gattier and evalute the biio mto n s utrtted. Ba a on my uiry of ftpe rson orpe rsons 4JI -E1 6-370 Benjamin P. Youman who manage the system, or fhse persons directly reapont tor gathertng the Information.

fte 0521/2012 i for mabon submit ted is. to the best of my knowledge and b elief, true. ac cur ate. and com plete. I am SIG N = PR IN C IPLE Plant Manager aware that thee aem significant penalttes tor submitting ftase Information.

biclutlg the possitilty EXof'UTI, OFFICER OR NAR MB mUR o N fine and risionme lfto knowing vUdns. AUTHORIZED AGENT COD NUMER MMJDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater durng this month.2. Flow e~dsted through this outlall 22 of 30 days during the month.EPA Form 3320.1 (Rev 01/06) Previous editions may be used. 1/6=12 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC=,,0RESS3 4=,, 'Wirn116 Road Warrenvifle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoo Cox/ENV SPEC DMR Mailing ZiP CODE: MAJOR (SUOR 01) CS 61010 ILDD48313 C01-0o MONITORING PERIOD MMIDD.YYY.I I MM!DDIYYYY FROM WWTP (FORMER 001C)External Outfall NOOISCHARGE I 04101/2012

{ TO{04/30/2012 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANTYYSIS PE Zinc, total SAMPLE ...... ...... ...(as Zn) MEASUREMENT 500 0109210 PERMIT --....... -1. 2GR Effluent Gross REQUIREMENT

-300A AVG DAILY MX ,.A Flow. In conduit or thru SAMPLE 0016 0025 3 0 Olitl CN treatment plant MEASUREMENT 50050 10 PERMIT

• Req. Mon.. Req. Mon Ma --Dally. CONTIN Effluent Gross REQUIREMENT 300A AVG DAILY. MX .. _J/d " -_" SAMPLE MEASUREMENT PERMIT " REQUIREMENT

"_ _ _' ... ."_""_"_.....

..SAMPLE MEASUREMENT PERMIT REQUIREMENT

_____ _____ _____SAMPLE MEASUREMENT PERMIT REQUIREMENT:

...........................

SAMPLE MEASUREMENT PERMIT 7 REQUIREMENT

,_. -_-.. ___.. .______..

.. .., , SAMPLE MEASUREMENT

"..PERMIT-

'* REQUIREMENT

_'._-.___.._.___""_" A .I cerfy under penalty of law that &ts docu, ment and afi attacttnents wr prepared -ider my TELEPHONE DATE PRINCIPAL.

EXECUTlVE OFFICER irction or supervsion in eccodrance With a system designed 1o assure aw qualified personnel-pop rtygatrad evaluef normatinSubmited.

BasedOn.m y o ~ , Of. the Person -P-,- .815 406-3700;

....Benjamin P. Y'ouman who manage "he system, or those persons dmrerty -9ste for gateringthe iftometon, tme ..1.. 05/21/2012 infornation submitted is. to the best of my knowledge and bel(, true. accurate, arid cnopete., arn PRINCIPLE Plant Manager aware tat there are soWlrcant penaties for submitting false informasion.

Including te posstbOty of E UTIVE OFFICER OR AREA NUMBER MM/O/YYYY_ _ , _ _ _ oR Pitw= -e and Irisiona ,ent f ,av tions. AUTHORIZED AGENT CODE, N M R_COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. I",O/12 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC Ai.DDRESS 43.W RtOad Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR MailIng Z]P CODE: MAJOR (SUBR 01) CS 61010 FL004831 3 i PERWs NUMBERf DOI1-0 UMSCHARGEn5 N'UMBER MONITORING PERIOD II MDYMM/DD/YYYY I RADWASTE TREATMENT (FORMER 001D)External Outfall*NO DISCHARGE FROMI 04/01/2012

] TOI 04/30/2012 I #i I ATTN: Zoe Cox1ENV SPEC __FREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER

____OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids, total suspended SAMPLE ...........

<0.8 1.2 19 0 02/30 CP MEASUREMENT 0053010 PERMIT -'15 30 TvoaPerMon COM-Effluent Gross 'REQUIREMENT , .....30DAAVG OLYMX Flow, in conduit or thru SAMPLE 0 02 3 A 01L0 Cp remntpatMAUEET 0.022 0.023 3 .........

... 0 01/01 CN treatment plant MEASUREMENT 500501 0 PERMIT Req. Mom. Req. Mon. -C-NTIN Mg* Dai.l....y CONTIN Effluent Gross REQUIREMENT

30DA.AVG DAILY MX. , .-.-SAMPLE MEASUREMENT PERMIT -_ REQUIREMENT.

._.___. ___ _.:.._._"._

_. .... .. ..SAMPLE MEASUREMENT 7 'PERMIT REQUIREMENT

• _"_"_"--_ " "_ _ " _"_"_ " SAMPLE MEASUREMENT PERMIT'REQUIREMENT " .._i -_. ._.--" .... -...SAMPLE MEASUREMENT

• PERMIT__....-__-__,___

PREQUIREMIET

". " ",,_.. ' _ : SAMPLE MEASUREMENT.PERMIT-REQUIREMENT.

A. .-_.._..._NAMETITLE ceratty under penalty of law thai fts documsent and al allactmenwt were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervsion In accordance with a system designed to essure that quarried personnel propeuty gathier arnd evalute fth Information submidtted.

Based on my bnqiry of Oem person of persons Benjamin P. Youman who manage the system. or those Perons directly responsle for gathteig the Infomation fti-37 05/21/2012 information submitted Is, to the best of my Imowledge aid belef. true, accurate, and complete.

i SIam OF PRINCIPLE Plant Manager aware tat tere are significant penafltes for subm1itdrn false inormation, ftktg fte possibity of SZ EC IvE OFFICER OR AR NA TMD OR PROME i nne and fiornIent fon violwn ons. AUTHORIZED AGENT CO NUMBER MMDDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow existed through this outfall 5 of 30 days durtng the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road IL0048313 PERMIT NUMBER FE01-0 DISCHARGE NUMBER _OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER (FORMER 001E)Extemal Outfall* NO DISCHARGE

[]61010 MONITORING PERIOD MM/DD/YYYY I MM/DD/YYYY FROMI 04/01/2012 TOI 04/30/2012 t lI Byron, IL 61010 ATTN: Zoe CoxIENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids, total suspended SAMPLE MEASUREMENT 500 0053010 PERMIT " --15 30 Effluent Gross REQUIREMENT

.',DAAVG DAILY -IL Weeldy GRAS Solids, total suspended SAMPLE .......MEASUREMENT

..... ..24.6 24.8 19 0 0107 GR 0053080 Other Treatment, Process PERMIT ...* " 30DAAV 100 Complete REQUIREMENT

.. S0DA AVG DAILY. MX ,"mg-. Weel.y GRAB Chromium, hexavalent SAMPLE ........*(as Cr) MEASUREMENT Soo 0103210 o

• PERMI, * .1 .2 DlGRAB Effluent Gross REQUIREMENT

.30OA AVG.' DAILY MX rag4. G RA Chromium.

total SAMPLE ........ ..... 500 (as Cr) MEASUREMENT 500 01034 10 PERMIT -.-.2 Effluenl Gross REQUIREMENT

"_""_30DA AVG "_ _ Daily GRAB Copper, total SAMPLE ..................

5 (as Cu) MEASUREMENT Soo 010421 0 PERMIT ----.5 , Effluent Gross _EUIREM. .DAGX ll, Daily GRA Iron, total SAMPLE (as Fe) MEASUREMENT 500 0104510 PERMIT -I Effluent Gross RUIEET _ ___. ..DAILY.MX.

ml al RD Lead, total SAMPLE ..... .... .5 (as Pb) MEASUREMENT 500 0105110 PERMIT --. * ' .... .2 A!.4 DG Effluent Gross -REQUIREMENT

.. -,. ,. ... -30DA AVG DAILY MX mg/L Dal.," R ..NAME/TITLE I Certily Uider penalty of law that this dooument and al attfChmert were prepared under my TELEPHONE DATE PRINCIPAL EXECUnVE OFFICER direction or supervsidon In accoidance with a system designed to assure that quaffed personnel TELEHON DATE property gather and evalule the Information submitted.

Based on my Inquiry of the person or persons 815 406-370 Benjamin P. Youman who manage the system, or those persons directly respons ble for gathering the wlormnation, the 8 406.3700 05/21/2012 inforiation subrrdtted is. to the beast of my knowledge and tefel. true. accuuste, and oonpate, Iam SEIA OF PRINCIP LE Plant Manager aware that them are amrifrcant penalties mbttfttng 16se Wormaton.

ncluding the possaiity ot XECUTIVE OFFICER OR AR NUMBER MMEDDIYYYY r(M on PRIM= I..e arid bIprislanment for knowing violations.

AUTHORIZED AGENT COD COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow exdsted through this outfall 5 of 30 days during the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 11f62012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 wintleld Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010= 1L0048313 i ERMiT NUMBER E01-0 0; G C HAR G 2l'JC 3lIUf MONITORING PERIOD MM/DD/YYYY I I MM/DD/YYYY STORMWATER (FORMER 001 E)Extemal Outfall* * ' NO DISCHARGE

-*I 4 FROM I1 04/01/2012 I To!04/30/2012 I J PAEEQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER

.E OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS Nickel, total SAMPLE ...500 (as Ni) MEASUREMENT 0106710 PERMIT .,, G"RAB1" Effluent Gross REQUIREMENT

".'_,_"_I.

-.30DA AVG DAILY.MX -.D. ..AB Zinc. total SAMPLE ...... ....... 500 (as Zn) MEASUREMENT 01092 1 0 PERMIT '2- ' .., -÷ t 2 Effluent Gross REQUIREMENT

." -30DA AVG DAILY MX mgoL. -.. ly.Flow, in conduit or thru SAMPLE 0.237 0.8a5 3 .. .... 0 02/30 CN treatment plant MEASUREMENT 500501 0 PEFRMIT:'

Re. Mon. Re.q. Mon. -,-"' -Twice Per Month CONTIN Effluent Gross REQUIREMENT 30DA AVG -DAILY MX Mgel/d"-SAMPLE MEASUREMENT PERMIT REQUIREMENT

"_._: _ _. ,.SAMPLE MEASUREMENT PERMIT REQIOREMENT

-._ 'SAMPLE MEASUREMENT PERMIT'- 'REQUIREMENT

., .,.....SAMPLE MEASUREMENT PERMIT REQUIR&MENfi "t" ' " .... ... .. " _: " NAMEJTTTLE I cartify under penalty of law that Wts document and alt attactments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTNE OFFICER direction or supervision in accordance with a system designed to ssmar tha quaifled personnel propery gather and evalrde fth information submitted.

Baed on my Inqfuiry of fte person or persona 46-70 Benjamin P. Youman *to manage the system, or hose persons cdrectly responsale tar gatherig the inorratiorr SI 05t21/2012 information submitted Is. to the best of my owledg and blief, true, acourate.

and complete.

la1 m SIGN R F PRINCIPLE0 1 Plant Manager aware Ma there am sigrniicant penalties for submitting false tormatim.

includig te possuly EXo UTIVE OFFICER OR AREA n~ ol ore anid l tof kI g AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning wastewater was discharged this month.2. Fire Protection drain water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/62012 PAGE 2 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4S0U Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road S DMR Mailing ZIP CODE: 61010 MAJOR (SUBR 01) CS COOUNG SYSTEM BLOWDOWN External Outfall NO DISCHARGE m IL0048313 001.0lMONITORING PERIOD MMDD/YYYY IMMIDD/YYYY FROM I 04/01/2012 1 TOI 04/30/2012 Byron, IL 61010 A'-rN: Zoe Cox/ENV SPEC _ _FREUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER EX OF SAPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Temperature, water dog. SAMPLE -89.9 15 0 01/01 CN Fahrenheit MEASUREMENT 0001110 PERMIT -- ' -- -Req. .... degF aOly CONN Effluent Gross -REQUIREMENT:

.,W._ ...._. ....... MO MAX -.______.pH SAMPLE 8.64 8.85 12 0 01/07 GR MEASUREMENT 0040010 We0l.PERMIT, 6 9 .- GRAB Effluent Gross ._.REQUIREMENT

-_._.:_*__MINIMUM

......_ MAXIMUM, .SU_._.._WeekyGRAB Solids, total suspended MAMUEE -1.9 1.9 19 0 01/30 GR Solds toaJsusened MEASUREMENT O0S30 10 .PERMIT .--, "' .., :-.. Req. Mon. Req. Mort.. "".. ....: .0053 0 SD300A AVG... DAILY MX mg/IL Monthly GRAB Effluent Gross __________

________ --Oil & Grease SAMPLE <1.6 2.1 19 0 01/07 GR MEASUREMENT 0055610 .,PERMIT S 20, Weeldy GRAB Effluent Gross REQUIREMENT 30DA AVG DAILY SAMPLE .... <0.0021 19 0 01/07 GR Chromium, total (as Cr) MEASUREMENT

________ 19 0 01/07 _ _0103410 PERMIT. 0. .we" --. -.0.2 Effluent Gross -REQUIREMENT.

_"_._.... " _-_- _.. .DAILY M[X m9. -. e GRA .Copper, total (as Cu) SAMPLE 0.012 19 0 01/07 GR MEASUREMENT

_ _ -.-_ _010421 0 PERMIT '. -,..'.I. .".... " 0.071 Wek.GA Effluent Gross -REQUIREMENT

,_ _"_" " DAILY.. .. _ ,I .. " " ..Zinc, total (as Zn) SAMPLE <0.0022 0.003 19 0 01/07 GR MEASUREMENT 0109210 PERMIT -...... .213- .433 m/L GRAB.Effluent Gross REQUIREMENT

-.- .SOA AVG. D ONLY m"I. Wee-ly GR.NAME I1T'LE I oCaty under penalty of taw OWa this docnm arid at attachments wer prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER dimxtion or suprAviW in a,,ordance with a system designed to assure that qualified personnel property gather and evalute mef Iormation subitrnted.

Based on my biquiry of ft peoton or persons 815 406-3700 Benjamin P. Youman who manage te systeh m or mtoe persons drectly respoosae for gathering me Ifomation.

the 815 406-3700 05/21/2012 ktonrnation su mitated is, to the best ot my kgowledge and belief, true. acurate. and oomplete.

am .1F PRINCIPLE

__Plant Manager aware that there are significant penalties for sutmltg slase iWotmiaon.

hrding the poSaibt ol EC E OFFICER OR AREA TYEoD pao Ra and 1- --leonment for v .AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Monitonng data for outfall 001-0 is included on attachment EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/12012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS

"'"" Exa,,' Gaa,, LL,,C ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 1 J DMR Mailing ZIP CODE: MAJOR Swarn GI I a.61010 I IS A(IAO~)4~I -I I 001.0 I PERMIT NUMBER I nercJ*cte

.,m,.bnea I I I,,/h,)

I*I U IIUIvIgl; r*1 I MONITORING PERIOD I COOLING SYSTEM SLOWDOWN External Outfall*"" NO DISCHARGE I MMWUIYYYY FROM F 1 4 MM/[DUITYY 04/01/2012 04/30/2012 I I QUANTITY OR LOADING QUANTITY OR CONCENTRATION

_ NO. FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE______________

______ ___ ANALYSIS Oxidanft, total residual SAMPLE .500 MEASUREMENT 340441 0 PERMIT .. ...... ..,. ..... ..... .05GRA Effluent Gross REQUIREMENT'

-.,-

• _,-_,__ DAILYMX mgML -1Weely G .-Priority pollutants total effluent SAMPLE ...... .. ... 500 MEASUREMENT 500081 0 PERMIT Rleq Mom. -. Pam. Req. Mon. mgl eky GRAS: Effluent Gross REQUIREMENT

..DAILY MX -_D 'mlI " 1 DAILEY.MX.

Mo___* "__

• __Flow, In conduit or thru SAMPLE treatment plant MEASUREMENT 50050 1 0 PERMIT Req. Mon. Req. Mon. C " ONI * .Effluent Gross REQUIREMENT.

30OA AVG DAILY MX Mgalld -Daily.C""TI" Chlorine, total residual SAMPLE 0.04 19 0 01/07 GR MEASUREMENT

....._0.04 19_0_01__7_OR 500601 0 PERMIT- --"- DA.L 0X Weekly 'GRAB Effluent Gross REQUIREMENT.

DAILY MIX 111911. _e__-., Hydrazine SAMPLE --- 500 MEASUREMENT 5O_8131310 PERMIT '.-. .011 .027 DailyWhen.

G Effluent Gross REQUIREMENT

"*DAAVG: DAILY MX -_" .--mWL GRAB SAMPLE MEASUREMENT PERMIT REQUIREMENT'

".'___ _" .-SAMPLE MEASUREMENT PERMIT.REQUIREMENT NAIM E fTrf i cartily under penalt of baw that docuetle mid* ai8q.l , attcmn ts were Prepared ef my TE EP ON DATE PRINCIPAL EXECUlrTVE OFFICER dection or supenrision in accordance with a systemn designed to assure tra qualified peonnel TELEPHONE DATE Benjamin P. Youman wo manage ft system. or 'Mse Perons diect respon815 ta gaft3 fthe 700omtat, 05/21/2012 Plant Mana ger Ioni subin i fed Is. to ft best of my Ivicniedge and belief. true. accurate.

and complete.

It r S IGTN' 1J RV V ICF PNRUIBNECI Pwa tate ,.r am s5fiareit penaftles for submrttnbg lalse mlormalhCkx*V fth posslito Af 6CUTIVE OFAGCER OR AREA NUMBERM_/DD/YY

_____ o______ Ifine and bunprisrrorment for knowin volatkons.

AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11602012 PAGE 2 0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADnDRESS 41-00 Winfitnff Reerd Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I IL0048313 I -PERMIT NUMBER I 002-0 DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY I I MMfDD/YYYY STORMWATER RUNOFF BASIN External Ouffall" NO DISCHARGE! ..I I I FROM I 04/01/2012 I TOI 04/30/2012 l I I I ATTN: Zoo CoY/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OFs TYPE ANALYSIS Solids, Total Suspended SAMPLE MEASUREMENT

________ __________

________005301 0 PERMT- 1 30 Effluent Gross REGUIREM1ENT

-,. .. .... .. ...mg/ Wee. GRAS Solids, Total Suspended SAMPLE MEASUREMENT

_____ ___ _____ _____0053080 .PERMIT Other Treatment, Process 3. .30 -.100 -_GRAB__"" Comolete ,REQUIREMENT

.' 30DAAVG " DAILY MX 1 'W "ek" GRAB Chromium, hexavalent SAMPLE ............

.(as Cr) MEASUREMENT 0103210 PERMIT ...01.016 D ..Effluent Gross REQUIREMENT

...... _ _.. -.."" .. .. -,, -300A.AVG -DAILY MX mg/L Da-Chromium, total SAMPLE (as Cr) MEASUREMENT 0103410 PERMIT 1 .2 * .Dtl, GRA Effluent Gross REQUIREMENT " _ _ -.-, -30DAAVG DAILY MX -', GRAS Copper, total SAMPLE .....(as Cu) MEASUREMENT 010421o0 PERMIT " -- -.02 -.041 D.GR Effluent.Gross -EUEMr ...... .,.PAAVG DAILYM( "mW. .Iron, total SAMPLE *.. .....(as Fe) MEASUREMENT 0104510 PERM... *.' 1X Effluent Gross REQUIREMENT Dmg/L DaBy GRAB Lead, total SAMPLE ......(as Pb) MEASUREMENT 01051 1 0 PERMIT ..063' .'.298 Effluent Gross .REQUIREMENT X .30AAVG DAILY MX. ..NAME/lTrLE I centiy under penalty of law uml ths docume and all anachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER duectko or supenrslon in ntaccrdaffae with a symesined to assure &A fladw parsonei property gather and evalute the Ilomtulon abrrrflled.

Based on my IqiJry ot te person orpero. .815 406-370persons Benjamin P. Youman who manage the sysem. or hos persons directly respornsble for gaWherg ft Wlruomrlon.

the 05/21/2012 Information submitted Is. to te bes of my knowlsege end 8eet, true. accurare.

and coarplte.

I am SIGU'FiPRiNCIPLE Plant Manager aware that Mtere er sgnhfkcaml penalties lot submillng false Infonrmaton. ng the post.ly of OFFICER OR AREA reoR ow peando _ __s__nmen_

__o_ _ __ow__ Violations.

AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6=2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC AUUDDRESS 430 Winfieid Road Werrenville, II 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTflJ 7hn flnvil=N' DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 iF ocoPER1Y'!

N*I ASED F_ 002-0 I niCpiiaGE NU'MBER MONITORING PERIOD MMIDDYYYY L MMIDDIYYYY STORMWATER RUNOFF BASIN External Outfall*NODISCHARGE FROM I 04/01/2012 TOI 04/30/2012 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER EX OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Nickel, total SAMPLE (as Ni) MEASUREMENT 0106710 PERMIT .011 .176Da8y GRAD Effluent Gross REQUIREMENT_.

_"_* _. __"_,_300A AVG DAILY MX GRAB Zinc, total SAMPLE (as Zn) MEASUREMENT 0109210 PERMIT ...-..047 .26 GRAB Effluent Gross REQUIREMENT " _ ;.- _____ 300A AVG DAILY MX mtg/L DallyR Oil and Grease SAMPLE MEASUREMENT 0358210 PERMIT s 1 -20 When GAGRA Effluent Gross REQUIREMENT*.-"....-.

"___,.__ -. _-i ___... 30DA AVG DAILY MX -' L -'- G Flow, in conduit or thru SAMPLE .....treatment plant MEASUREMENT 50050 1 0 PERMIT Req. Mon. Req. Mon. When-Effluent Gross -REQUIREMENT 30DA AVG DAILY MX M ---Dlaciarging SAMPLE MEASUREMENT PERMIT_REQUIREMENT

..... _ _ _ _ _ __ _SAMPLE MEASUREMENT PERMIT REQUIREMENT

_ _.. --, -SAMPLE MEASUREMENT.PERMIT REQUIREMENT r _ .-NANM'LE I certify under penalfy of law Mtat fts documend and all aftachnwts were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervision in accordance with a system desgned to assure tw quaified psmoneoO proper egatsreand evaomerf thoseaonsn woied. ased on my cnyry of ft person or persons r. .wa..- 815 406-3700 Benjamin P. Youman who manage thyehjster or mose persons 4ec'ty ryer the pa ft lnfonnaonr e85 05&21/2012 Information submitted la. to ftn best of my Iwledge and b"lt. Oue. accurate.

and copolete, I am IGN RE RINCIPLE ____Plant Manager aware ow fem ame agreant penatles tat s laftaton',onfb, iucng the posst of EXECUTE OFFICER OR AREA NUMBER MDDYYYY T O Ifrn and trrisomsvla for knowing violations.

AUTHORIZED AGENT CODE NM R__COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 2 0 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 April 2012 Page 1 of 2 MONITORING DATA: CWBD C WB lw Rock River DATE Temperature mgd Flow deg F cfs 04/01/2012 82.5 15.02 6,880 04/02/2012 81.7 14.38 6,860 04/03/2012 83.6 16.80 6,930 04/04/2012 83.6 17.00 6,800 04/05/2012 77.6 15.63 6,630 04/06/2012 75.1 17.27 6,510 04/07/2012 76.4 21.46 6,380 04/08/2012 79.6 17.00 6,170 04/09/2012 80.8 12.47 5,930 04/10/2012 78.7 16.48 5,770 04/11/2012 73.5 16.79 5,680 04/12/2012 79.5 17.40 5,610 04/13/2012 79.0 16.16 5,490 04/14/2012 85.3 22.60 5,380 04/15/2012 89.9 16.13 7,590 04/16/2012 89.9 12.77 8,410 04/17/2012 82.3 18.26 8,170 04/18/2012 81.8 15.13 8,000 04/19/2012 87.2 18.33 7,350 04/20/2012 86.2 15.58 7,120 04/21/2012 77.7 22.24 6,970 04/22/2012 79.1 21.17 6,630 04/23/2012 82.5 16.50 6,430 04/24/2012 83.4 21.37 6,330 04/25/2012 86.4 19.51 6,160 04/26/2012 86.4 21.41 6,100 04/27/2012 81.3 22.92 5,940 04/28/2012 81.3 24.83 5,840 04/29/2012 82.2 20.47 5,930 04/30/2012 85.2 15.69 6,130 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012]Reports\April\April 2012 ATTACHOI.doc V ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 April 2012 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of April 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite was used this month. Bromine compounds were not used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 30 of 30 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month. The Rock River TSS value was 44.3 mg/L on 04/09/2012.

The CWBD TSS value was 1.9 mg/L on 04/09/2012.

5. Rock River flow for April 2012 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in April 2012. (Special Condition 15).K:\BYR_CHXBYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\AprillApril 2012 ATTACHO1.doc Exek n.Exelon Generation Company, LLC www.exeloncorp.com Byron Station 4450 North German Church Road Byron, IL 61olo-9794 June 15, 2012 LTR: BYRON 2012-0064 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of May 1, 2012 through May 31, 2012.On 05/03/2012 between 03:45 and 05:12 cooling tower water from the Unit 1 Natural Draft Cooling Tower (NDCT) basin flowed over the basin into the storm water ditch located on the east side of German Church Road. The flow was approximately

1.1 gallons

per minute for an estimated duration of 87 minutes resulting in approximately 92 gallons of cooling tower water flowing through storm water Outfall 003, East Station Area Runoff. The cause of the overflow is a large number of NDCT fill packs fell into the cooling tower basin in a short period of time. This caused the delta level across the debris fence in the NDCT to rapidly rise from 0.5 feet to 2 feet which pushed the water out of the basin. Byron Station Operations personnel took immediate measures to lower the cooling tower water level in the basin of the NDCT to stop the overflow.

In addition measures were taken to remove the fallen fill packs from the NDCT basin debris fence to lower the delta level across the fence.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Benjamin P. Youmav Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments PERMrIrEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN. C'.wI1FNV RPFC:P NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0046313 AD"-PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MMIB WYYYY I MUMIDOYYYY DUR Mailing ZIP CODE: 61010 MAJOR (SUBR 01) CS DEMINERALIZER REGENERATE WASTE (O01A)External Outfall* **NOOISCHARGE-

°FROMI 06101/2012 I To 05/31/2012 QUANTITY OR LOADING QUANITIY OR CONCETtON NO. FREQUENCY PARAMETER EX OF TY.PLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Solids, Total Suspended SAMPLE ....... 21 2.1 19 0 01/30 08 MEASUREMENT Effluent Gross n xu Chromium, hexavalent SAMPLE ........(as Cr) MEASUREMENT Effluent Gross C.hromium, total SAMPLE ..... ...500 (as Cr) MEASUREMENT 0103410 ~ y:- -Effluent Gross Copper, total SAMPLE 500 (as Cu) MEASUREMENT 0104210 ez- ..... ..2' *'-'-Effluent Gross 7 Iron. total SAMPLE .. .... 50 (as Fe) MEASUREMENT Effluent Gross Moog" Lead. Total SAMPLE ...... Soo (as Pb) MEASUREMENT Elffluent Gross-Nickel, total SAMPLE Soo (as Ni) MEASUREMENT____

010671 0 M --4.-7 -ýEffluent Gross i NAME/1TTLE I Derlity under penalty of law MtWa tks docueant alt Sttaflefts were prepared T, myL ONE DATE PRU414PAL EXECiLwVE OFFICER directi or supendsm bi accordance with a system to assure mat wuafid prpet g~r noeatt V romao sbmte a~sed m frinqur v*" perso or persons 815 406-3700 Benjamin P. Youman wfo manage tite systm or tose pereonsi dtecy resporsWAe lor gaere erlolmat Vsnt t1e -152012 inluomaw is. to ahe best of my knomtedge and be"et. tue. acrate. ant comrlete.

I amn SIGNPUREOF/NCIPLE Plant Manager aware tat &mere are sqndam penalties for faske informat.

wdudig owe p 0adt of EXECUTIVE OFFICER OR AREA-____n all _____- __o_________n__ (Or _ _i_ _ Vi_ _. AUTHORIZED AGENT CODE NUMBER MM/DD/YY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastowater during this month.2. Flow existed 31 of 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1.0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DUR)PERMII-EE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvitle.

IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATIN: Zoo Cox/ENV SPEC IL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD MM"1DYY I I "D/YYYY DMR MaIling ZIP CODE: 61010 MAJOR (SUOR 01) CS DEMINERALIZER REGENERATE WASTE (001A)External Outfall*"NODISCHARGEE" FROMI 05/01/2012 I ToI 05/31/2012 I O QUANTITY OR LOADING OUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANAOFYSS TYPE Zinc, Total SAMPLE ... .... ...00 (as Zn) MEASUR.MENT So 01092 10 4' r -.. .. ..... .....4'" "Wrb *" Effluent Gross = -- *S, Flow, in conduit or thru SAMPLE 3l 0 1/1C tetetpatMAUEET 0.033 0.094 3 ......* ...... 0 01/01 CN treatment plant MEASUREMENT_________________

____________

50050 10 zT?~T -4~(~ 4lt ~~2L V;Effluent Gross- -in MEASUREMENT SAMPLE

.', " : SAMPLE MEASUREMENT

..- .. : ... ..t -W, SAMPLE MEASUREMENT SAMPLE MEASUREMENT NAMEmILMVE I cey under penty of law at this document and an aftactwents were prepared under my dimecton or upemn accordance with a system designed to a.ssur tat quati geonnet TELEHN D propery gatner and evabtie the itonfratioa submitted.

Based -i my hqiuy o te peeat or Benjamin P. Youman who manage the system. or ftse pemros direcdy mspnsase for gatherfg hme a oiona70n, 0 06/15e12 iformiation subtited es. to the best O my and ke. mru. accurate, and Oomrete. i am SUIVTUREft Of#MCIPLE Plant Manager aM tha ere ar signicant penaftes for submtig tate inormatwio frlotiding fth of EXECUTIVE OFFICER OR N EEY oE me and iipMantmit tor knowing vnioelns.

AUTHORIZED AGENT C NU MMIDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 ,P©D Q&L fUAUV COWt7 PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Bron, t 61010 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (OUR)IL0048313 B301-0 PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MMIDWIYVYY L_ MMDD[YYYY DMR Mailing ZIP CODE: MAJOR (SUDR 01) CS STP PLANT EFFLUENT (FORMER 0018)tdM Ouffall" NO DISCHARGE 61010 FROMI 05/01/2012 I TOl 05/311/2012 I ATTN: Zoe CoxIENV SPEC QUANTITY OR LOADING QUANTrrY OR CONCENTRATION NO. FREUENCY SAMPLE VALUE VALUE UNITIS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE SODS0.38 0.50 26 5.5 6.0 19 0 020 24 (20 Deg. C) 0031010 o ,.: 10E rs*"',.c ' ..-,- ...../ %0" S Effluent Gross " _ -mr. ..Mw 000010- ~. ~ss. *0p '--too- +*Solids total suspnde 0031010 7t~U ~ ~ -v- tttt uV;rr.Effluent Gross .""a, I Flow, in conduit or thru 0 0/0P C PHSAPEo...

O.L ... .....757...........1 0 OlrOI GR MEASUREMENT SAMPLA MEASUREMENT

______________________________________.. 4-MEASUREMENT,, NAME/flfl.E r catty under peanty d law that tris doumeli and al atiachmfls were prpae under mty TLP EDT PRINCIPAL EXCUIE OPP1CEN erect'on ot suetso in --"ora.ew asl-ern asgne to asurema quae peTLEPONEDAT properl gather and evaleuthe mle oranf i aubrirted.

Based mi my inqur at the persis or persists , .-- 1 4230 Benjamin P. Youman who manage die system, or tho~se persora directl reapoiwdil Ioa gasiarg oe b'Jorrnai mam 068155406470 Floomwano subitd e. to me atsty knowledge and ben. true. accurate, and crnrete , ani " SI0 4ATUR 0.0'PRINCIPLE 3 001 Plant Manager aware hai there are sagnlcant genfltes tar submflm tatie entramabna.

Sichudg tIN posatktdy a EXfECUTIVE OFFICER OR JSA NMBRFMIWY trw mm " and kiprn~is~ma for mnowng Vi~litioniS AUTHORIZED AGENT CODE NUMBER ______________

COMMENTS AND EXPLAtATION OF ANY VIOLATIONS (Reference lS attMachments here)1. Flow existed through this outfall30 of31 days during this month.EPA Form 3320-1 (Rev 01/0'(6) Previouseditions, may be used. ¶1uIb2012 PAGE 1 (a IRQ PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvitle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (OMR)IL0048313 C01-0 PERMfT NUMBER DISCHARGE NUMBER DMR Mailing ZIP CODEt MAJOR (SUBR 01) CS WWTP (FORMER ODIC)Extenal Outfl.'.NO DISCHARGE "J " 61010 MONITORING PERIOD MMIDWYYYYI MMIDWIYYYY FROMI 05/01/2012 ITOI 06/31/2012 I Byron, IL 61010 A't't': Zoo Cox/ENV SPEC ____ ________ _____________

__________

A : / SQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS SAMPLE ........u...d 3.9 6.5 19 0 o0230 24 00530 10-. #, '.r a rSO'30 -~T ~$4-,-m Effluent Gross i Chromium.

hexavalent SAMPLE Soo..........n5l (as Cr) MEASUREMENT 0103210 U~qy 4r tV$YX ~ rXk~d 1 ~-Effluent Gross A i a Chromium.

total SAMPLE SI (as Cr) MEASUREMENT 500 010341 0 44p ;Effluent Gross 1, Copper, total SAMPLE (as Cu) MEASUREMENT A-.010421 0 rz ~ ~ t'~ ~v"~Y' ,~eff'..tI tiYkfj 4Y Eff'l. ,. .-r--oss' *:A?2fl.., ', r ; ' -.-."-- .*-Iron, total SAMPLE ....... ... So (as Fe) MEASUREMENT 010451 0 .V-- #'* 4 Effluent Gross Lead. total SAMPLE (as Po) MEASUREMENT 0106110 ~~. ~ "' -~'S ;t Effluent Gross -,-'..-, v.Nickel, total S..... ...... ......5.(as Ni) MEASUREMENT-5--

01067 10 so~r -A> )"~rr.- A~i k~ t:4 sN&-m~Effluent Gross 02 1 "1NANE1TnLE i certfy under penalty o law thit this doocment and a" aanes TELEPHONE DATE PAICPAL EXECUTIVE OFFCER riaction or supensvn m accordance with a system designed to assure tar qualired personnel I"doperty gater and evalute the uitonmation submitted.

Base an my tnuty of the person or persons 815 406-37I0 Benjamin P. Youan who manage tro system. atrtose permons directly reaponsie icr gaitrerng the intonnaton.

mte 6W, rvI/2012 informatiPn submtna ed is, to the best of my Ikowledge and beief. true. acoiate, and complete.

I am S0I6 01RE O2IRINCIPLE-Plant Manager aware that there am .signficant penaltis for s lubmitig false tomnrmnon, fIduic mhe possity of EXECUTIVE OFFICER OR AREA NUMBER MM/D YYYV Sm O Pn jif and mrosmmfor kowmgviolain.

AUTHORIZED AGENT CODE NMRMD COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hee)1. There was no discharge ol processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outeall 24 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 14/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (OUR)PERMIT'EE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER I MONITORING PERIOD I MMDYY I MMIu D/YY OUR MaIling ZIP CODE: MAJOR (SUBR 01) CS WWTP (FORMER 001C)Exemal Outtall***NO DISCHARGE 61010 r-" .........FROMI 05/0112012 1 I 06/31/2012 Il i Byron. IL 61010 ATTN: Zoo CoxIENV SPEC QUANiTIY OR LOADING QUANTITY OR CONCENTRATION NO. FREUENCY PARAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE Zinc. total SAMPLE (as Zn) MEASUREMENT

_ _I _ _500 01092.10 3.... ý, ... .:. Z;E~ffluent Gross Flow, in conduit or thru Awicdulrtn APE 0.015 0.023 3 """......

0 01/01 CN treatment plant MEASUREMENT 0.01_ 0.023 3_0_____O 50050 10 -'4i1 AOL 4.4f' -~Effluent Gros" "1J- -j .. ..... *SAMIPLE MEASUREMENT MEASUREMENT SAMPLE MEASUREMENT MEASUREMENT NAMEITITLE I C 10Y under p o law 0a On documen and al auftonts were pepared under my PRWCIPAL EXECUTIVE OFRCER doctn or supesion in acowdance wilh a system designed to assure 0l quailed persannM TELEHON DATE prOPe gather and evaklre sueated. Based on my riqsy ofmf perso or persons Benjamin P. Youman who manae sWsTe or Vime peros diectly respnsl ff .te 4g0"-3-70Vie 06m15e2012 il ormatlon submittaed ito. tohVe boo of my Wowiedge and belief. tWAe waccrate, and corroleze l amn WUNGflREOF~PMhIlPLE Plant Manager aware 0V Viem am 50gificant penalt for wrmbmg false Womuo. kcx, V posesity of EXECUTIVE OFFICER OR N EEY ORp RM fni a b u for f I .AUTHORIZED AGENT DE NUMBER M__ _ _ _ _ _ _COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/=2012 PAGE2 a 0ORQAUWp 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 1L0048313 PERMIT NUMBER F 601-0 DISCHARGE NUMBER FROMI MONITORING PERIOD DMR Mailing ZIP CODE: 6 MAJOR (SUBR 01) CS RADWASTE TREATMENT (FORMER 001 D)External Outfall* NO DISCHARGE EZJ 1010 MM/e D/YYYY 05/01/2012

!UMIDDIYYYY 05/31/2012 1 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Solids, total suspended AMETCO cO 19 0 023M C MEASUREMENT

__________

____ ____ ____ ___Effluent Gross -..Flow, in conduit or thru SAMPlE treatment plant MEASUREMENT

_ 0.021 0.023 3 ............

0 01/01 CN 5005010 All,~ 2V 4~~~t%~I Effluent Gross si ' -.4 MEASUREMENT

... t~.. eq`ýw-.J-au, A -h~j ! -4MEASUREMENT

____ ____________________________

SAMP MEASUREMENT A. 4y t v v ~ % 'l ~ ;A~ril ~y. ~SAMPLE MEASUREMENT mamwnnm. i candty under penalty oS law thai the document and eli atauntt were prapare under ity LPOEDT Benjamin P. Youmnan who manage the stmn. at those pesoms asusal tow gatherig the mtormattw, the "IN IL 6I5 mnfotmet,u etitldtta is.to ate beat oS my knowledge and belt ntree accurate.

and complete.

tamiEOnIL

__ _ ____________

Ptant Manager aware that thr are signifcant penaie tfuortrtkrlg tabse inam~adat.

having the ipmsrbuty EXECUTIVE 0FFIER OR ~ NME MDYY m end IccKuowing vidatiw. AUTIhORIZED AGENT NUMBER MM/I)D/Y______Y COMMENTS AND OF ANY VIOLATIONS (Reference all auachmetmnta here)1. Flow existed through this ouflall S ot 31 days during the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. --'1/6/2012 PAGE 1©XI PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)1L0048313 E0l-0 PERMIT NUMBER DISCHARGE NUMBER I ~ MONITORING PERIODI I MMIDDnYYYY I FROMI TOl I MWD/YYYYl _ !0501I/2012 I I 05131/2012 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER (FORMER 001E)Exteinal Outff**t NO DISCHARGE 61010-I I QUATMITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER EX OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Solids, total suspended MEAMPLENT.

Solids, total suspended M 0053010 j J'c Other Treatment, Process complete Chromium, hexavalent SAMPLE ......(as Cr) MEASUREMENT 010321 0 A. 2;.,'Effluent Gross Chromium, total SAMPLE ..... .(as Cr) MEASUREMENT 01034 10 T ' z A 4 r?Effluent Gross Copper, total SAPL (as Cu) MEASUREMENT, SIMI 0104210 'ASA "t""-. " ' -" Effluent Gross -L.', ,-,' L Iron, total (as Fe) MEASUREMENT Soo Effluent Gross k. -:4 Lead. total SAM .....(as Pb) MEASUREMENT 500 01051 10 ~ ? ' e'Af, :ct w.I*4 h r.Effluent Grossa NMf I Cerfady under penany of law Mat Me documern and an altadcments were prepared under my DATE PRInCPAL EXECUTIVE OFFICER dietion or aupertw in acmorance wem a sysaem designed to assure mat quaftled pertannel TELEHON DATE9g3a and evauite Via rormaion sufrnifed.

oadnht my ikxluy d te person or pem rizsC c 815 406-3700 Benjamin P. Youman who manage ft sWe. or tose directly responsae for gam"ang ae onitrtw. V6e -0615212 Bomnan submfn is, to the bestS nVo'etd and betl, Ue, awrawe, andomwrs.

tam S1GWMuuRE OFýMCIPLE Plant Manager aware mat mere are penaties for infornatmon.

jfljfl the posa ilyS EXECUTIVE OFFICER OR AREA NU E MMDO/YYYY Sand prreo-mAnt for knowing a.UTHORIZED AGENT COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow existed through this outfall 2 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/2012 PAGE 11 Cqr---)'Py P- a ey \ýý0 PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 EO1-0 PERMIT NUMBER DISCHARGE NUMBER F MONITORING PERIOD UMID/YYY I I -DwfYYYY DMR Mailing ZIP CODE, MAJOR (SUBR 01) CS STORMWATER (FORMER 0OIE)External Outfall***NODISCHARGE 61010 I .......FROM J)l0510112012 To= o//201DI2 I I QUANTITY OR LOADING QUANITrY OR CONCENTRATION NO. FREQUENCY PARAMETER EX OF TYMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSI Nickel, total SAMPLE ...... ..... ...... 500 (as Ni) MEASUREMENT 0109210 -- .Effluent Gross 1'~ 2,10 L a i Zinc total SAMPLE ...... ...... 500 (as Zn) MEASUREMENT 0109210 bye, en~ .Af-M'- ý W~N~5 F , Effluent Gross FoicodiortrSAPE 0.314 0.575 3 .... ... 0 02/"3 CN treatment plant MEASUREMENT MEASUREMENT

_____ _____ _____SAMPLE MEASUREMENT 4W.v~ --t Q~vtt~H. i'V 41 7&3V@&M MEASUREMENT

• . -- .r _r .,& jf < -..- A 4 3. '%..r IMUE/I1TL.E canny under penally law vma mes doc~ment and all aeacflr~en warn prepared under my TELEPHONE DATE PfiCPL, EXECUTIE OPPICER dlrcha ow aupervmain i accordance wale a system deige to dial qualifed persmnne____

Benjamin P. Youman who manage the aystem r those peioss deafly resportaihe gatherig t~e miormasn, me SINR FIC- "u/ , J 06/15/2012 atomrnation aubmutad la, to the hemst my knowleg and hefler. tree, accurate, and complete.I amin ~ lRE~WIL Plant Manager aware dial mere are peate Ice sulmziniti false inlomiainm.

kiM~s' mhe Pm~atity S EXECUTiVE OFFICER OR ARE UBR MM/DD/VYYY fle a xn la ne and bin utlrnmnn l for Igrowin vi a w .A U O R E D G N TO O COMMENTS AND EXPLANATION OF ANY VIOLATIO)NS (Reference all attachmen~ts hem)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning wastewater was discharged this month.2. Fire Protection drain water was not discharged this month.EPA Form 3320-1 (Rev 01106) Previous editions may be used.'...

1/6/2012 PAGE2 Q QMLIW,='.

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)OUR Maling ZIP CODE: 61010 PERMITTEE NAMEIADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Wintield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoo Cox/ENV SPEC IL0048313 PERMIT NUMBER F 001-0 DISCHARGE NUMBER MONITORING PERIOD MMIDW0YYYY j I MM/ID/YYYY MAJOR (SUDR 01) CS COOLING SYSTEM BLOWOOWN External Outfall"..NODISCHARGE FROM 05/01/2012 J OL 06/31/2012 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Temperalure.

water dog. SAMPLE ...... ...... ...0 Fahrenheit MEASUREMENT

.....9. 5 0 0/1C 0001110- _HSAMPLE ...... 8.25 8.73 12 0 01/07 OR pit MEASUREMENT-Effluent Grossppv tr.'r. i -- .e A: Solds, total suspended

...... 1.6 2.1 19 0 01/30 GR Solds Ioalsusened MEASUREMENT 0053010 7, ., -.. 7" .,-. ITc. .. "7 Effluent Gross a Oil & Grease SAMPLE .. .... <1.4 c0.4 19 0 01/07 OR MEASUREMENT oflun Gros .-+ ----r +.... ,t.," -- "........Effluent Gross Chromium, total (as Cr) SAME <0.0021 19 0 01/07 OR MEASUREMENT

_____________

____ ____01042 10 iiV Cj Za S4-Effluen Gos -:v '-;. ,: ....-.. -= .-... ---: --' ... .t4 ~ ~'-Effluent Gross .f-properl gaml ad e) SAMPLE t...... .. .. .... 0.013 19 0 01/07 mR Colper toai as u) MEASUREMENT Effluent Gross _--- -: 1P+, ;-p .. '+" ....PAMLEr potal (as EXECUTIVEE<0.0022 0.ERO 24 19 0 01/07 OR Zin, Effluent Gross :"' "+, °-+""...NCMENTS AND EXP.tLAN A uTI r PeOlty oL laT MOt (n R umef t al atftachmems were )maro uner m ONE DATE P1 .MnL EXdaCUtaE OFFCER outclt00 1 r sup edion attcorhaen with a system design to assur tha quatied Pronel EPApFeoy ga330 an eva(e m0 1/rmaiono suednie. Basen an my mauiry ou sde pe or .ons OD 0,1PAGE1 Beniannin P. Yournan whg manage the system, or rhose Persos dir-t,'y repmb tm gaiemrn the infrmation, the 406-37PL 0615=212 intonnabon submittdne is. t o am bowl of my knowmlede and 1belie. true, =,'cu,,ra.

andm =nmpMW.I m, SIN GR 1:n Plant Manager aware that there are sqgnificant penabaes for su latin e tabsnformtion fxing the postlf of EXECU TIME O~C ER OR AREAJ TIM OaRm 1110110 em for knowin viltl AUTHORIZED AGENT 1COD NUMBER -MMIDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Raefernce all attachments hem)1. Monitoring clata for outfali 001-0 is included on attachmrent EPA Form 3320-1 (Rev 01/06) Previous editions mnay be used. 1/6=212 PAGE 1 QAO@DFfl (uQUA PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 A'f-Nz 7GB CinxIFNV SPEC NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 001-0 PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MM,.D/YYYV I MMIDD/YYYY DMR Mailing ZIP CODE: 61010 MAJOR (SUIR 01) CS COOLING SYSTEM BLOWDOWN External Outfall*

• NO DISCHARGE

"" FROM L 05/01/2012 J TOI 05/31/2012-I QUANTITY OR LOADING QUANTITY OR CONCENTRATION

.FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Oxidants, total residual SAMPLE E500 Priority pollutants total effluent MEASUREMENT500 Effluent Gross iFIAK r = 1 i a Flow, in conduit or thru SAMPLE 20.55 27.56 3 ....... 0 0101 CN treatment plant MEASUREMENT 20;56 50050 10goy txg1g es- 't .. -Effluent Gross m a 02=1.) 1Z Chlorine, total residual SAMPLE ....... 003 19 0 01/07 GR MEASUREMENT Effluent G ross -: -i. -_-Hydrazine AMELE .50 Effluent Gross M ~ SU M;. .81 18 : -'"k,& ,: " t' .i- "- , r,, NAM~fliTES rAMPLm SAMPLE MEASUREMENT properly gather anid evalula the Wnomutior sumttdM. Based an Fmy binquii of the person or persons 1 40370615 2 Benjamin P. Youmnan who manage Vve system, of fthee parsona directly reapomfle Icr gaMVterigte intorkone.

th SIGNJWIII OFYMNCIPLFl61521 Plant Manager int-rsrnteubmistted is, to tie betat 01r wmy tinoieg arid beirS, true. scoe, andl M0T1*51. Itarn XCTVEOFCRR AE Plan Man er aware triat there are swinicant penalties tor aubrti falsgIe infrmiiation.

htflng the possiady s XCTVtOFCRO NUMBER MMMIDDYYYY

______ an__MINIM fin~e and irrrrisiermsnt tar mnowinG vioations AUTHORIZED AGENT CODE__ __ ____________

CMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all etutchnienta here)iEPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1621 AE POOR UAL9fl ©©F%.

PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACIULTY Byron Nuclear Power Station LOCAliON 4450 North German Church Road Byron. IL 61010 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 002-0 PERMIT NUMBER DISCHAR3GE NUMBER MONITORING PERIOD FROM 06/01/2012 TOI 06/31/2012 DMR Mailing 13P CODE-MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfall* **NODISCHARGE 61010 A I* I: -"=-V t awcn/ ~rlc, _ _ _ _ _ _ _ _ _FREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE[ýý!<ANALYSIS SAMPLE .......Solds MEASUREMENT Colis, Total Suspended SAME (as Cu) MEASUREMENT 00o308 1 --.... ....Effluent Gross Come, oltalSMLe......

..Ihroniu. toexaaltSML (as CF) MEASUREMENT 0103210 t* _Effluent Gross -.-r.ron,. tota SAMPLE .......(as Fe) MEASUREMENT (as Pb) MEASUREMENT Effluent Gross NAME/iTII1E ICertfy wnder pena~ly Cl law t'hai tys tclornmeit andi at alla'mens waee wnder' myTEEONDArl llINCIPAL EXCTV OPRICER ot m accaruarce with a systes desige to assue thai qpualfed pereonen_________________

Benjamin P. Youman who manage te ysem. r tiseepeisons duedy rsibetr gatherng te tdonmain.

the 1 0-70 61/21 Iofonne. submd is. t he best ol my knSAedPe end beel. true. ..cura.e. a1 lam WGNJ.URE OF 7 INCIPLE Plant Manager aware tha there em esignrtcant penaltis tar eutmoing talse etfomiabon.

erchdul the pcealbulty EXECUTIVE OFFICER OR NUMBER MM/DDJYYYY owe a wm and irlpflsraonlleltafr IImoWmiQ vidla~eS.

AUTHORIZED AGENT co ___ ___________

COMMENITS AND EXPLANATION OF ANY VIOLATIONS (Reeec ail attachments here)1. No Turbine Building Fire and Oil Sumnp or Generic Non-Chemical Metal Cleaning Wastawater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. I/6/2112 PAGE 1 0 ROUR-InA 0 -r y C 0'0)ý I P, NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 002-0 PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD S MMIDDoYYYY MMIDONYYY PERMI'IEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenve, II 60H55-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/IENV SPEC OUR Malling ZIP CODE.MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfall"**NO DISCHARGE M ...61010 FROM L 05/01/2012 ITOl 05/31/2012 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel, total SAMPLE ......(as Ni) MEASUREMENT 0105710 ' ----o #-M ., -* .-.,.Effluent Gross 21 Zinc, total SAMPLE (as Zn) MEASUREMENT Effluent09 1Gross0

' i -,, -, r'":*". -;y. ; .010921 0 v ______T t~Oil and Grease SAMPLE .MEASUREMENT 03582 10 77p4"- '"-~"--~c2;~

~ t-~.~ P'~P -Effluent Gross Flow, in conduit or thin SAMPLE treatment plant MEASUREMENT 5005010 ts > e qy 4 Jeq.o 4 Z--Effluent Gros t MEASUREMENT SAMPLE MEASUREMENT

_ _ _-__-- & ,.SAMPLE MEASUREMENT NIMce/TITLE I 8rdty unier penany Of law Mat Oif document and al a were prepared under y TELEPHONE DATE PRdICIPAL EXECUTIVE OFFIR diection or supeNvsim In accordnlce with a system desined to assure flnt qualdied persainei TELEHON DATE propeuty gamer and evaitenme infomatinsubmittad.

Based on my inqiw of me persor pso .sti5 406-3700 BenjarminwP.

Youman whomanage fu system, or fte pson=airecy responsl far gotering the informaioen.

u 061512 infrmfamtion submnitteduis to the best of my ivoaedigea nd belief. trse, accutrate.

ean comrqtse Iam SIGAG R OFWCtNM__

____________

Plant Manager aware Man there are signicant penaftes tar subtmitg fare ionnatlim.

holding me poflay of EXECUTIVE OFFICER OR AREAM Tweoo a l t and uipnaintat for bvwtng vomatione AUTHORIZED AGENT CODE NUMBER MM/OD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmenta here)1. This discharge point was not used this month.2. Them was no discharge of processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1//2012 PAGE 2 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 May 2012 Page 1 of 2 MONITORING DATA: CWCWB D Flow Rock River DATE Temperature mgd Flow deg F cfs 05/01/2012 86.0 22.71 6,180 05/02/2012 92.5 19.66 6,160 05/03/2012 96.1 22.35 6,090 05/04/2012 96.1 19.40 5,990 05/05/2012 91.5 26.25 5,960 05/06/2012 90.2 21.26 6,040 05/07/2012 90.2 16.10 6,490 05/08/2012 89.0 20.31 7,090 05/09/2012 86.9 20.77 7,560 05/10/2012 86.3 21.37 7,660 05/11/2012 89.2 20.81 7,610 05/12/2012 90.7 27.56 7,380 05/13/2012 88.9 22.68 7,170 05/14/2012 90.6 15.14 7,060 05/15/2012 91.1 20.80 6,900 05/16/2012 91.1 19.23 6,570 05/17/2012 85.6 20.10 6,470 05/18/2012 93.2 22.87 6,360 05/19/2012 94.7 25.09 6,150 05/20/2012 95.0 17.36 5,960 05/21/2012 95.0 13.79 5,710 05/22/2012 84.0 19.80 5,620 05/23/2012 86.0 18.06 5,460 05/24/2012 84.4 18.97 5,310 05/25/2012 93.0 19.39 5,000 05/26/2012 89.0 24.88 5,140 05/27/2012 99.0 20.18 5,140 05/28/2012 99.0 18.83 5,100 05/29/2012 97.8 18.99 4,860 05/30/2012 94.0 19.70 4,700 05/31/2012 84.8 22.67 4,820 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\May\May 2012 ATTACHO L.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 May 2012 Page 2 of 2 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of May 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite was used this month. Bromine compounds were not used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month. The Rock River TSS value was 25.3 mg/L on 05/07/2012, 31.3 mg/L on 05/14/2012 and 22.8 mg/L on 05/29/2012.

The CWBD TSS value was 2.1 mg/L on 05/14/2012 and 1.1 mg/L on 05/29/2012.

5. Rock River flow for May 2012 was >2400 cfs therefore daily temperature calculations were not required this month. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in May 2012. (Special Condition 15).K:\BYR_C1{BYRON.DB\ClerkWMonthly Discharge Monitor Rpt\2012 Reports\May\May 2012 ATTACHO1.doc ExekJn.Exelon Generation Company, LLC www.exeloncorp.comN Byron Station Nuclear 445o North German Church Road Byron, IL 61o10-9794 July 23, 2012 LTR: BYRON 2012-0082 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276'

Subject:

Byron Station Monthly Discharge Monitoring Report I In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of June 1, 2012 through June 30, 2012.If there are any questions regarding this report, please contact Ms. Zoe Cox, Supervisor Environmental/Radwaste, at (815) 406-3035.Respectfully, Benjami P. your Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments EN-AA-105 Revision 4 Page 14 of 14 Attachment 2 Example Verification Completion Form Page 1 of I Verification Documentation Correspondence/Letter number: 2012- ON 9- Origination Date: 7-19-12 Agency/External Stakeholder:

IEPA Submittal Due Date: 7-23-12 Recipient of Correspondence:

IEPA WPC CAS #19 (name and title if known)Purpose of Submittal:

June 2012 DMR Originating Office: E] Cantera E- Kennett Square I] Site Byron (specify)Preparer:

Zoe Cox 0 tw % /(print) (sign) (date)Peer Reviewer:

David Starke 4 9 (print) (sign) (date)Certified Mail Return Receipt Requested:

FI]Yes -INo Approvals (check box if applicable)

Attach additional page for comments.

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDIMMDDYYYY I M1DYy DEMINERAUZER REGENERATE WASTE (001 A)External Outfall* -NO DISCHARGE FROMI 06/01/2012 I Tel I ........ I I Uwir30/2 12 I Byron, IL 61010 ATfN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS SAMPLE 9.7 10.1 19 0 01/30 08 Solids. Total Suspended MEASUREMENT 0053010 PERMI -',--15 .30 flr , CM Effluent Gross REQUIREMENT

.._._._"- -_,__ _0D.A AVG DAILY MX f.... L Mon. .O.:.Chromium, hexavalent SAMPLE 500 (as Cr) MEASUREMENT 500 0103210 PERMIT ..-. .12 EffluentGross REQUIREMENT 3_.,.___...

.0DA AVG DAILYVMX rW'- ,... .. ..Chromium, total SAMPLE ..................

5 (as Cr) MEASUREMENT 0103410 PERMIT ..,..,, ... ' 2 mg/ " Da GRAB" Effluent Gross IREQUIREMENT.

30DA AVG ' ...... --Copper, total SAMPLE ...... ...... ...... 500 (as Cu) MEASUREMENT 010421 0 PERMIT * ..5 .1 Effluent Gross REQUIREMENT

_.__ .SDA AVG DAILY MX MOI *____ -Iron, total SAMPLE ..500......(as Fe) MEASUREMENT

...... __500 0104510 PERMIT -.- ,.,. 1 'E ff lu e n t G ro s s R E Q U IR E M E N T A," -, ."" , W,_ :_"_, D a il ,G"R".A..

..B- , Lead, Total SAMPLE ............

...... ...... 500 (as Pb) MEASUREMENT g'0105110 PERMIT .. " ..2 .4 Effluent Gross REQUIREMENT 3_ _ __" _ SODAAv( OAII , -/ Di GRAB Nickel, total SAMPLE ...... 500 (as Ni) MEASUREMENT 0106710 PERMIT -..-V2mIayR Effluent Gross

"_, -, .-Daily -RAB NEIr'LE cendy under penany of law that thi document and an artachmems were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER drectin or superir~n in accordance with a system designed to assure that quatified personnel prope rtygather an d eva knethe inform ation subm itt Wl. B a~se d an my inqu iry o te pe rson or pe rsos - : .t , --6 5 4 6 3 7 0 0 Benjamin P. Youmnan who manage the system, or those persons directly responsible for gatheting the information, the I07/23=12 inlormation submitted is. to the best of my knowledge and balief. true. accurate, and cormplee.

I am SIGNATIE O RINCIPLE Plant Manager aware that thera are signiicant penalties for submnittg false iftormation.

irnduding the psibity 01 EXECUTIVE OFFICER OR AREA OR PR. me and imprisinmemnt for knowing violations.

AUTHORIZED AGENT ODE NUMBER MMDDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed 29 of 30 days during this month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER A01-0 -DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY MMIDD/YYYY DEMINERALIZER REGENERATE WASTE (O01A)External Outfall" NO DISCHARGE

[ " FROMI 06/01/2012 TOI 0613012D12 Il I PUANRTITY OR LOADING QUANTITY OR CONCENTRATION No. FREQUENCY PARAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Zinc. Total SAMPLE ...... ...... ...... S00 (as Zn) MEASUREMENT 0109210 PERdI- ,.-.. --Dl2 GRAB Effluent Gross p2UIREMEN. " _ "'___" 30DA AVG DAILY MX Flow. in conduit or thru SAMPLE treatment plant MEASUREMENT 0.046 0.132 3 0 01/01 CN 500501 0 PERMIT Req. Mon. Req. Mon. L Effluent Gross REQUIREMaENT 300A AVQ DAIJY..Ym 4tx Daily CON~hN.SAMPLE MEASUREMENT

'PERMIIT.-.

.REQUIREMENT

_ _., ;.. -,._"_'SAMPLE MEASUREMENT REQUIREMENT , ......_,_....SAMPLE MEASUREMENT PERMIT-REQUIREMENT

.-.........

.-SAMPLE MEASUREMENT PERMIT ROQUIREMENT

,__r_ _ -SAMPLE MEASUREMENT,NAEmTITLE I certify under penalty ot law that this document and all attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIE OFFICER direction or supervision In accodance with a system designed to assure that qualified personnel properBym Pater and evalute the infomiation submitted.

Based an my inquiy of the person or persons .-) 815 406-3700 Benjamin P. Youmnan who manage the system, or those persons directly responasise for gathering the infomtation, te 8,5....3.0 07/23t2012 information sumimned is, to the best ot my Inotiedge and bellet. true. accurate.

and comlete. I am,,p E OI-RIN PLE .Plant Manager aware dhat there are significant penalties for submritting lalse information.

Including the EXECUTIVE OFFICER OR AREA T"WOD OR Pmm, Tr line and imprsionment Ifr knowing vielatons.

AUTHORIZED AGENT 4OD NUMBER MMIDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 NATIONAL POLLUTANT DIS 9 ARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT-rEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvitle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER B01-0 DISCHARGE NUMBER B I MONITORING PERIOD STP PLANT EFFLUENT (FORMER 001B)External Outfall I MM/DD/YYYY I I ToI MM/DD/YYYY

-- I FROMI 06/01/2012 06r3J/2012 I* **NO DISCHARGE

= ..I lOUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREOUENCY VALUE VALUE UNITS VALUE VALUE VALUE UNITS O ANALYSIS TYPE B/3D. 5-Day SAMPLE (20 Deg CASUEE 0.42 0.58 26 ...... 6.0 7.0 19 0 02/30 24 (20 Deg. C) PMEASUREMENT 003101 0 PERMIT 5.3 VA10.5 Id "TcP30 60 X g/Lo Elfluent Gross REQUIREMENT 30DA AVG DAILY .... ,DAAVG D-LY X T PMont COMP24 pH SAMPLE............

...... 7.54 ...... 7.58 12 0 02/30 GR MEASUREMENT 0040010 PERMIT 6 ., ... Tw,. .a M Effluent Gross 6RETUIREMENT Mroh SAMPLE Solids, total suspended MEASUREMENT 0.17 0.23 26 ...... 2.3 2.8 19 0 02/30 24 005301 0 PERMIT 5.3 10.5 bld 30 ,60 Effluent Gross REIGUIREMENT 300A AVG QAILY MX .30DA AVG DAILY fAX fL TWICe Per Month COMP.4 Flow, in conduit or thru SAMPLE Fo.IcodiorhrSAPE 0.006 0.013 3 ...... ...... ...... ...... 0 01/01 CN treatment plant MEASUREMENT 500501 0 PERMIT Req. Man. Req. Mon. ... .... .y- a-"O" " Effluent Gross REQUIREMENT

.30DA AVG, DAILY MX M. .. .._qt .. :"-'--SAMPLE MEASUREMENT PERMIT REQUIREMENT

..SAMPLE MEASUREMENT PERMIT ,REOUIREMENT

....-.SAMPLE MEASUREMENT PERMITF______ BI=RO W _ _ _ _ _ __ __NAMEMITLE I certify under penalty of law that this document and alt attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFRCER direction or superaron in accordance with a system designed to assure that qualmed personnel propezy gather and evaluethe inmormation submitted.

Baseanminhulotheperonrpersons 815 406-3700 Benjamin P. Youman who manage the system, or those persons directly respnsible for gathering the intormation, -e 07/2o372012 information submitted is. to me best of my knowledge and belief, true. accurate.

and complete.

lam SIGNAIM OF INCIPLE Plant Manager aware that there are significant penalties for submitting false information.

including me EXECUTIVE OFFICER OR AREA TIMED CA fITIE_ ine and hoprtsisrem tol Mnowing violatits.

AUTHORIZED AGENT CODE NUMBER- MMDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Row existed through this outfall 25 of 30 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER I CO1-0I I DISCHARGE NUMBER I MONITORING PERIOD MMIDD/YYYY I MMIODIYYYY WWTP (FORMER 001C)External Outfall*NO DISCHARGE FROMI 06/01/2012 TOI 06030/2012 l l---- I Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC ______ _______________

___________

__________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TPE SAMPLE ............

...... ...... 4.1 4.2 19 0 02130 24 Solids, total suspended MEASUREMENT 005301 0 15 30 Effluent Gross REQUIREMENT

..-""._" -:__ -_.., 30DA AVG DAILY MX mng&L Twice Per Month COMP24 Chromium, hexavalent SAMPLE ............

...... ...... Soo (as Cr) MEASUREMENT 0103210 .2 Daily GRAB Effluent Gross REQUIREMENT

• _ _ .. 30,DA AVGi DAILY MX .Chromium, total SAMPLE ............

...... ...... 500 (as Cr) MEASUREMENT 010341 0 PERMIT .. .2...* ,D... 1 2GA Effluent Gross REQUIREMENT

.. ...DA AVG DAILY M" ____ ...Copper. total SAMPLE ............

.....(as Cu) MEASUREMENT 0104210

• PERMIT ,,,.- ....'.5 1 .GRAB Effluent Gross REQUIREMENT " _ _ 301A AVG pALY Mx mg/L Iron, total SAMPLE ............

............

500 (as Fe) MEASUREMENT 0104 1 0 PERMIT .... ..... 1. Dily Effluent Gross REQUIREMENT

• - ,...*DAILY MX Lead, total SAMPLE ...........

...... ......(as Pb) MEASUREMENT 0105110 PERMIT .2 .......Effluent Gross REQU__IREM__ENT

._._-._ 30DAAVq DAILY MX _ .P. al GRAB Nickel, total SAMPLE ............

...... 500 (as Ni) MEASUREMENT, 0106710 PERMFIT ..1 2 ..Effluent Gross REQUIREMENT

.30DA AVG DAILY MX trtL. Daly GRAB.NAflTh. I certify under penalty of law that this document and all attachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUtiVE OFFICER direction or supervnisin in accordance with a system designed to assure that qualified personnel

_properly gather and evaute the Infonation subritted.

Based an my inquiry ol the person or persons 815 406-3700 Benjamin P. Youman who manage the system, or those persons directly responsible lor gatheng the inlormation, the 07r2312012 information submitted is. to the best of my knowledge and belel, true, accurate.

and conplete.

I am SIGNARE OF NCIPLE Plant Manager aware that there are significant penalties lfo submitiing lalse including the possb4 of EXECUTIVE O CER OR AREA T'n O ine and imprisionment for knowing vioatons.

AUTHORIZED AGENT CODE NUMBER MMDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outfall 17 of 30 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (OMR)DMR Mailing ZIP CODE.MAJOR 61010 PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 Norlt German Church Road Byron. IL 61010 ILMr13 IUMBC01-0 (SUCR 01)PERMIT NUMBER I I DISCHARGE NUMBER -CS MONITORING PERIOD MM1DDIYYYY I I MMIDDJY~yyY WWTP (FORMER 001 C)External Outfall* I I NO DISCHARGE

"]FROMI 06/01/2012 1 TOl 06o132012 Il I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Zinc, total SAMPLE ............

...... ...... 500 (as Zn) MEASUREMENT 0109210 PERMIT ... ...... .....1.. 2 Effluent Gross REQUIREMENT

.. .._._*_. 3I0IA AVG DAJLY MX it... patt -GRAB Flow, in conduit or thiu SAMPLE treatment plant MEASUREMENT 0.015 0.029 3 0 01/01 CN 5005o 10 PERRMIT. Rq. Mon. Req: Mon.Effluent Gross REQUIREMENT.

30DA AVG DAILY MX * .. ' D. l C...I.SAMPLE MEASUREMENT PERMIT REQUIREMENT

"_____,__"_

SAMPLE MEASUREMENT PERMIT ,REQUIREMENT

-...SAMPLE MEASUREMENT PERMIT REQUIREMENT

_ _ _. -,-SAMPLE MEASUREMENT

.!,e rr.- , REQUIREMENIF SAMPLE MEASUREMENT PEF.WIT,I" NAMElhTrLE I cenrty under penalty of law that Otis document and alt attachmets were prepared under my TELEPHONE DATE PRINCIPAL EXECU~lVE OFFICER directlon or supervision in accordACe weth a system designed to assure that qualified pemronnel property gather and evaJute the1 nforniatior Based an my inqu of the perton or pemons 8 815 406-3700 Benjamin P. Youman who manage dhe system. or those pesoons directly responsime for gathering the information, te -07/23e12 infontation submitted is. to the best of my knowledge and belief. tre, accurate.

and complete.

I amn ___O__Plant Manager aware that there are significant penalties tor sumtitting false informiation.

including the possiblity of EXECUTIVE OFFICER OR AREA onPW OR ' io line and imupnssorment for knowing violations.

AUTHORIZED AGENT CODE NUMBER MMMD/YYYY COMIENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 PERMIT'EE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe CoxIENV SPEC NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 6o1-0 PERMIT NUMBER DISCHARGE NUMBER FM 1 ONITORING PERIOD MMIDOIVYYY MMIDD/YYYY FROM 0610112012 1TOI 06/3a(2012 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 RADWASTE TREATMENT (FORMER 001 D)External Outiall I NO DISCHARGE

[ ...QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS SAMPLE ............

...... ...... <0.5 <0.5 19 0 02/30 CP Solids, total suspended MEASUREMENT 005301 0 PERMIT ,.- .-. 3w Effluent Gross ,REQUIREMENT

_ -:_r_" _ 30DAAVG DAILY MX. m_,, Per ...,_ :I flow, in conduit or thru SAMPLE i, Fo.icodiortrSAPE 0.022 0.023 3 ...... ...... ...... ...... 0 01/01 CN treatment plant MEASUREMENT 500501 0 PERMIT Req. Mon. Req. Mon. d Effluent Gross REQUIREMENT 30DA AVG DAILY MX ...-SAMPLE MEASUREMENT PER~dltT REQUIREMENT

_SAMPLE MEASUREMENT-PERMIT REQUIREMENT SAMPLE MEASUREMENT PERMIT REQu~Mi3ENT-SAMPLE MEASUREMENT PERMIT REQUIREMENT

.._"_."_.-.._"" SAMPLE MEASUREMENT PERMIT* REQUIREMENT

.__ ..... , INAMEnITTLE I ceritiy under penalty of law tha this document andal,, artaidirents were Prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER diection or supeism mn acance with a system designed to assure Ithat qualltled personnel L OD property gatner and evalute the informaon submeted.

Based an amy inqus of phe peron or persons Benjamin P. Youman whot manage the system. a those persons directy responsible for gatherng the inonmiaion.

te ,,...L 815 406-3700 07t23e2012 infomation submitted is. to the best of my knowledge and betel. true. accurate.

and conmlete.

I am SIGNA 6E OF P fCIPLE Plant Manager aware tha there are significant penalties for submitting false inlormaton including the posaiblity of EXECUTIVE OF ER OR AREA"MEDO TED fine andimonsionmen lot knowing violations.

AUTHORIZED AGENT CODE NUMBER MMDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. Flow existed through this outtatl 4 of 30 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMfl-EE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvire, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 OMR Malting ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER FMONITORING PERIOD MM/IDD/YYYY I MM/DD/YYYY STORMWATER (FORMER 001LE)External Outfall* '

• NO DISCHARGE FROMI 06/01/2012 I TOI 06/30/2012 A'I-N: Zoo Cox/ENV SPECFRE_________UENC___Y_____

ATTN: QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE OF TP PARAMETER O VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE SAMPLE ............

...... ...... 50 Solids, total suspended MEASUREMENT 0053010 PIERMIT .5 30 mg&. Weekly GRAS Effluent Gross REQUIREMENT

__._._. ..30DA AVG DAILY MX ____eky GA Solzds, total suspended SAMPLE ............

...... ...... 16.4 17.8 19 0 01/07 GR MEASUREMENT 0053 80 PERMIT ...30 100 Other Treatment, Process REQUIREMBT 30PDA AVG PAILY MX rag/L. Weekly GRAB C om plete ..._. .. ... ..._ *__"_. .._"_" -__..._._,_"_..___"_'_" "_i_" Chromium.

hexavalent SAMPLE ...... 500 (as Cr) MEASUREMENT 010321 0 PERMIT .D*a* ... .1 m Effluent Gross REQUIREMENT

_ _" _.... 3ODA AV/G. DAILY MX ..... .GRAB Chromium, total SAMPLE ............

....... 500 (as Cr) MEASUREMENT 0103410 PERMIT ....'.... ... 1 2 Effluent Gross REQUIREMENT_,,..PA AVG DAILY .,g.I -Dolly GRAB Copper, total SAMPLE ......0...... ....... S0o(as Cu) MEASUREMENT 0104210 PERMIT ...m- -- .5 1 Effluent Gross REQUIREMENT*_._..

_'_"__ 30DA AVG DAILY W m* Daply GRAB Iron, total SAMPLE ............

....... 500 (as Fe) MEASUREMENT 010451 0 PERMIT.. ..,,. .G Effluent Gross REQUIREMENT, ' ._ ____ .._ .DAILY MX mg/L " DtGR Lead, total SAMPLE ............

....... 500 (as Pb) MEASUREMENT-0105110 PERMIT 1 , " .2 .4 Effluent Gross REQUIRENENT I. 30DAAVG DAILY MIX moJL Da, .GRAS NAIIE/TITLE I under penalty of law that this document and al) attadments were prepared undoe my TELEPHONE DATE PUNCWPAL EXECUTIVE OFFICER direti .sevsioi aicordance with a system designed to assure etat fuaiased personlet lATE property gather and evalte the information submtted.

Based on my tquuy at the persos or persons Benjamin P. Youman who manage the sysem, or those persons direcey responsbe for gateing the information, the 07/23/2012 infeoation submned is, to the best of my imowedge and b.eief tnue. acwrate. and conipee. I am SIGNA 6E OF PRIOPLE Plant Manager aware hat there are signifcant penatties fo. subtting false Information.

including the possalty ol EXECUVE OFFICER OR AREA WEDon iemMn life and ithl)preOnment lfo knowing Viations.

AUTHORIZED AGENT MMID COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow existed through this outfall 1 of 30 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4460 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 1L004"113 PERMIT NUMBER FE01-0 DISCHARGE NUMBER MONITORING PERIOD MM/DD/YYYY I I MMIDD/YYYY STORMWATER (FORMER 001 E)External Outfall.NODISCHARGE

-o FROMI 06/0112012 I TOI 06/30/2012 Il I Byron, IL 61010 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Niclel, total SAMPLE (as Ni) MEASUREMENT 500 0106710 PERMIT ... .1 2 Dai" GRAM Effluent Gross REQUIREMENT

_ _ _ _, 300A AVG DAILY MWX- DayGRAB Zinc, total SAMPLE .........

......(as Zn) MEASUREMENT 50_0109210 PERMIT 2. " -3 2Daiy GRAB Effluent Gross REQUIREMENT ITODA AVG PA1LY MX Flow, in conduit or thru SAMPLE FoicodiortrSAPE 0.262 *0.262 3 ...... ...... ...... ...... 0 02/30 CN treatment plant MEASUREMENT 50050 1 0 PERMIT Req. Mon. Req. Mon. M Effluent Gross REQUIREMENT 30DA AVG. DALY M .ga-d ".Twice Per Month CONT-SAMPLE MEASUREMENT

• "PERMIT REQUIREMENT SAMPLE MEASUREMENT PERMIT REQUIREMENT.

-"'_ " -" SAMPLE MEASUREMENT PERMIT REQUIREMENT

-SAMPLE MEASUREMENT PERMIT NAMTITLE I cility under panally oa law that this document and all attachmennts were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or m accordance with a system designed to assure that qualifed personnel property gather and Ovatute the infomtionnak sutMed. Based on my mnqwiy of the peison or peisons 815i1 401 30 Benjamin P. Youman who manage the system, or those persons directly responsible for gatherng the iojmalon.

time 815 --- 07/23/2012 intormation submitled IS. to the best of my kunowiedge and belief, tue. accurate.

and complete I amn SIGNVURE OF7RINCIPLE Plant Manager aware that there are significant penaltis tot submitdng talse information, inricdng the possi"t o EXECUTIVE OFFICER OR AREA 7tIPD OR PRSOir.a li'n and _ _n __s_ __nt _or Imowing votati__ns.

AUTHORIZED AGENT COD NUMBER MM/DDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmenls here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning wastewater was discharged this month.2. Fire Protection drain water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/12 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: 61010 MAJOR (SUBR 01) CS COOLING SYSTEM BLOWDOWN External Ouffall.NO DISCHARGE

• MONITORING PERIOD MMIDD/YYYY I I MMOD/YVYYY FROM I 06/0112012 I Tot 08/30/2012 I ATTN: Zoe Cox/ENV SPEC ______________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO FREQUENCY PARAMETER OF___SAMPO.LE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Temperature.

water deg. SAMPLE ............

101.0 15 0 01/01 CN Fahrenheit MEASUREMENT 000111 0 ERMr .. ...., ,_ ._ RPq. Lion.Effluent Gross REQUIR EI"Odeg F Daily OONP" pH SAMPLE ............

...... 8.21 ...... 8.66 12 0 01/07 GR MEASUREMENT 0040010 PERMIT6 Effluent Gross

." N "I -I I Solids, total suspended SAMPLE ...... ...... ....... 3.3 3.3 19 0 01/30 GR MEASUREMENT 005301 0 PERMIT ,..,, *, Req. Mort. Req. Mon.Effluent Gross R-QUIREMENT, ._.___*____.__

_ _ __.* .DAAV ODNLY MX mg/L GRAB Oil & Grease SAMPLE ...... ......4 .4 19 0 01/07 R MEASUREMENT

...... ..... <1.4 <14_9___/0_G 0055610 PERMIT ..0 ... .. ",Wey G E ff lu e n t G ro s s _ _ __U _E_ _ _-TD A A V G -"A. .y M X " "_" _' " Chromium, total (as Cr) SAMPLE .........

<0.0021 19 0 01/07 GR MEASUREMENT 01034 10 PERMIT 0.2 W"GA Effluent Gross REQUIREMENT.

--... ....__.-*, " -Copper, total (as Cu) SAMPLE ............

.............

0.011 19 0 01/07 GR MEASUREMENT 010421 0 PERMIT ., .-.. ....,. 0.071 mg/I " Weekly GRAB Effluent Gross REQUIREIAENT

• " -"__""*.._ .... .--Zinc, total (as Zn) ..... ...... <0.002 0.0025 19 0 01107 GR MEASUREMENT 010921 0 PEftMrr ,;,** ,..,. ... :213 .433 GRAB Effluent Gross REQUIREMENT 3,.......ODA AVG DAILY ingW NMErnTLE I certify under penalty of law that this document and aal ttachments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER drectim or supervision In accordance with a system designed to assure that qualified personnel property gather and evatute tre infomation submritted.

Based an my inquiry at the person or persons Benjamin P. Youman who manage the system, or those persns dvicey responrsbe for gathring the intomnamn.

the 02402312 information submitted is. to tre best of my knowtedge and befef, true. accurate, and complete.

an SIGNA RE OF PRVCIPLE Plant Manager aware hat there are significant penalties for submitting lalse infonr.ation.

induding the possituty d EXEC UIVE OFFICER OR UMDY TP R fine and imorisionment for knowing vioations.

AUTHORIZED AGENT CODE NUMBER MM/DDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Monitoring data for outfall 001-0 is included on attachmenL EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES).DISCHARGE MONITORING REPORT (DMR)PERMI'TEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 A'l-T, ----~t -D.L0OT NO13 PERMIT NUMBER 001-0 DISCHARGE NUMBER OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS COOUNG SYSTEM BLOWDOWN External Ouffall 61010 MONITORING PERIOD I MM/DWYYYY I I MM/DD/YYYY FROM I 06/01/2012 I TOI 06/3012012 I' *

• NO DISCHARGE

°P QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY RM1E N. OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYS TYPE Oxidants, total residual SAMPL .... .... ...... ....MEASUREMENT 003 19 0 0107 GR 340 -10 PERMIT ..... ...0 3404410..

' .PA'LVU mg/. Weekly GRAB Effluent Gross RBOuIREMEIT

.___ w R A.SAMPLE ...... ...Pnority pollutants total effluent MEASUREMENT 500 500081 0 PERMIT Req. Mon Req. Mon.Effluent Gross R9OUIREMENT

___"_ PDAILY xLmg/L W-,y GRA Flow. in conduit or thru SAMPLE treatment plant MEASUREMENT 21.09 29.39 3 ............

.............

0 01/01 CN 500501 0 PERMIT Req. Mon. Req. Mon *.. .Effluent Gross REQUIREMENT .DA DAIY .-.-"...i" SAMPLE ...Chlorine, total residual .AS E N ......500 MEASUREMENT50 5006010 PERMIT .... ..,eR Effluent Gross REQUIREMENT

._,. .. wee.,.k.X .GRAS Hydrazine SAMPLE ............

...... ......MEASUREMENT

_ 500 8131310 PERMIT Q27 m.,. ."..011. ..027 aily When GRA Effluent Gross REQUIREMENT

-, ,A., .,, --. ,De_. , SAMPLE MEASUREMENT PERMIT REQUIREMENT .. .., ;, ..SAMPLE MEASUREMENT PERMIT REQUIREMENT

'_. -___"._.._..

...__" ._NAMErTITLE I certiy under Il olaw that t ns 0 ;= i aMtademets ere preard un 'my PRINCIPAL EXECUTE OFRCER afrection or supennion in accordance with a system desig to assure that qualbied peisonnel TELEPHONE DATE ppetygather and evalute the informaion subirrtted.

Based n my nquiry o0 the person or persons 815 406-3700 Benjamin P. Youman who ranage tie system. or those persons directly responsibe fo0 gathenng me itfnmeat~t, e SIGN I.RE OF PINCIPLE 07/23/2012 Plant Manager information submitted is. to the bes of my knowieoge and beLief. iue. accurae, and complete.

I am EXECUTIVE OFACER OR that there are signiftiant penalties for subinfittg lalse intonnatlon, including tie of NUMBER MMIDD/YYYY TYM m fine and imprisionment for knowing violations.

AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612' PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITiEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER f -0 02 DISCHARGE NUMBER OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfall I

• I NO DISCHARGE

] " 61010 MONITORING PERIOD MM/DDIYYY I MM1DDIyYYYY FROM I 06/01/2012 I To!06/30/2012 I* I ATTN: Zoe Cox/ENV SPECFREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER

______N. OF SAYPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALSS TYPE SAMPLE ............

......Solids. Total Suspended MEASUREMENT 0530 10 PERMIT -,,. -15 39 r;Effluent Gross REQUIREMENT

,, 300A AVG DAILY M X g/I. W R SAMPLE ............

............

Solids. Total Suspended MEASUREMENT 0053080 PERMIT Other Treatment, Process " PMI .Weekly 301 Complete R.EQUIREMENT

-*. 0DA 4VG DAILY MX f.ttOL Weekly GRAS Chromium, hexavalent SAMPLE ..........

...... ......(as Cr) MEASUREMENT 010321 0 PERMIT AVG AILYM,..Da.lG.A..011

.016 Effluent Gross R=IREMENT

• - 30_.AVG "ILyMX_ (11. DaRy_ GRAB Chromium, total SAMPLE ............(as Co) MEASUREMENT 010341o0 PERMIT 2.., *.. ....D 1 2 Effluent Gross RE.QUIREMENT.

3.)A. AVG DAILY GRAB Copper, total SAMPLE ............

...... ......(as Cu) MEASUREMENT 010421 0 PERMIT " ..,..025 .041 Effluent Gross REQUIREMENT "30_,,,__"____*OA AVG DALY MX. maj ., Daly GRAB Iron, total SAMPLE ...........................(as Fe) MEASUREMENT 010410 PERMIT ...... mg/L Daily GRAB.Effluent Gross REQUIREMENT DAILY MX Lead, total SAMPLE ............

...... ......(as Pb) MEASUREMENT 01051 1 0 PERMIT .........

.. .. ... .063 .298 '1i Effluent Gross REQUIREMENT

.__ _ _ _____ SODA AVG DALY MX n'Lai GRAB NAME/TITLE I cartify under penalty df law thai this document and at artachmenms were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction or supervis in accedance wth a system designed to assure t110 qualified personnel property gather and evalue the iofnnason submitted.

Based on my inquiry of the person or persons 15 406-3700 Benjamin P. Youman who manage the system, or those persons directy responsible for gathering the infonration, the 07/2312012 infoimaton submitted is. to tIne best of my knowledge and tore, accordle.

and compltea Iam SIGNAJRE OF ItINCIPLE Plant Manager aware that there are significant penalties for submitting false infoaiatian.

Including tie possbulty Cof EXECUTIVE OFFICER OR AREAN TYPED O PFrED line and impiianment for knowing vitatains.

AUTHORIZED AGENT CODE NUMBER MM/OD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmenta here)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection.

Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, 1i 60555-5701 FACIULTY Byron Nuctear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATT'N: Zoo Cox/ENV SPEC OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER F MONITORING PERIOD I MM/DD/YYYY I MMIDD/YYYY STORMWATER RUNOFF BASIN External Outfall""' NO DISCHARGE

[j) ...FROM I 06/01/2012 STOI 0602012 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER VAUVLEX OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX IS TYPE Nickel, total SAMPLE ............

.........(as Ni) MEASUREMENT 0106710 PERMIT --.011 .176 Effluent Gross .REQUIREMENT

.300AAVG D.ALY MX ,Dai GRAB Zinc, total SAMPLE ............

......(as Zn) MEASUREMENT 0109210 PERMIT ..... -. .. 047 .21 Effluent Gross REQUIREMENT

• _,_"_,, _ .. .... 30DA AVG. DAILY MX rr19/L "- : .. GRAB SAMPLE Oil and Grease M ASU LE ...... ...... ...... ......MEASUREMENT 03582 1 0 PERMIT .... ..... ... .... 15 20 When G Effluent Gross REQUIREMENT G __*_ ._.,, 3ODA AVG DAILY MX GRA- Dschami Flow, in conduit or thru SAMPLE ..................

treatment plant MEASUREMENT 500501 0 PERMIT Req: Mon. Req. Monr. MVd -..,, .When E Effluent Gross REQUiREMENT 30A AVG D)AILY MX. ..-.M ._ ,.

• ischArgng SAMPLE MEASUREMENT PERMIT REQUIREMENT

..___..__.SAMPLE MEASUREMENT PERMIT REQUIREMENT

__"_" SAMPLE MEASUREMENT PERMIT REQUIREMENT

________________

____NAMtEtmrl I certify under penalty of law that this document and all attaolments were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFRCER direction or supervision in aocordance with a system designed to assure that quariied personnel property gater and evalute tie mitoniatim sub mitted. eased on my iquity ot the person or persons Benjamin P. Youman who manage the system. or those persons diractry responsible for gathering the Information.

the O 815 40&3700 0722012 informaton submitted is. to the best of my Inoetedge arid betet. true, accurae. and compite. I m SIGNA RE OF P CIPLE Plant Manager aware that them are sgniticant penals for submitting latse intormation.

incuding the possibtty ol EXECUTIVE OFFICER OR AREA NUMBER TSPo R PIM line and imprisioniment Ior knowing violations.

AE MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 2 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 June 2012 Page 1 of 3 MONITORING DATA: D CD Rock River DATE Temperature mgd Flow deg F cfs 06/01/2012 85.8 23.50 5,060 06/02/2012 86.8 29.39 5,090 06/03/2012 93.9 15.58 4,790 06/04/2012 93.9 5.58 4,540 06/05/2012 87.0 0 4,310 06/06/2012 88.2 0.201 4,190 06/07/2012 93.0 13.78 3,880 06/08/2012 99.6 22.64 3,740 06/09/2012 96.4 28.23 3,560 06/10/2012 97.0 22.35 3,070 06/11/2012 95.5 16.75 2,830 06/12/2012 95.3 24.58 2,680 06/13/2012 89.4 20.26 2,790 06/14/2012 92.1 22.56 2,740 06/15/2012 92.1 24.85 2,630 06/16/2012 97.0 25.63 2,710 06/17/2012 97.0 24.49 2,690 06/18/2012 98.7 16.35 2,750 06/19/2012 99.6 21.98 2,590 06/20/2012 99.1 21.26 2,510 06/21/2012 98.4 25.22 2,470 06/22/2012 96.2 20.56 2,320 06/23/2012 98.4 26.56 2,330 06/24/2012 98.4 23.64 2,350 06/25/2012 95.1 17.34 2,240 06/26/2012 93.3 23.75 2,250 06/27/2012 92.3 20.54 2,280 06/28/2012 101.0 22.39 2,200 06/29/2012 99.5 23.16 2,120 06/30/2012 98.7 28.61 2,120 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\June'une 2012 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 June 2012 Page 2 of 3 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of June 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 29 of 30 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month. The Rock River TSS value was 34.4 mg/L on 06/11/2012.

The CWBD TSS value was 3.25 mg/L on 06/11/2012.

5. Rock River flow was <2400 cfs in June 2012 therefore daily temperature calculations were required during that time period. (Special Condition 12).6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in June 2012. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\June\June 2012 ATTACHI01.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 June 2012 Page 3 of 3 Per Special Condition 12, in the event the Rock River flow is <2,400 cfs, daily calculations will be undertaken to demonstrate compliance with the water quality standard.

The calculations are based on hourly measurements, averaged over a 24-hour calendar day for Rock River flow, main Rock River temperature, CW Blowdown flow, and CW Blowdown temperature values. Results of the calculations shall be reported in the DMR on a monthly basis.Calculation results are in the following table: Date Average Average Average Average Calculated Water Rock CW M/U CW CW Temperature Quality River Temperature Blowdown Blowdown at edge of Standard Flow (F) Flow Temperature mixing zone Temperature (cfs) (gpm) (F) (F) (F)6/22/12 2286 75.6 16060 94.3 76.3 90 6/23/12 2325 75.2 16076 93.9 75.9 90 6/24/12 2353 75 16105 95 76 90 6/25/12 2248 75 15985 92 75.9 90 6/26/12 2250 73 15883 93 74 90 6/27/12 2290 74 15942 95 75.2 90 6/28/12 2210 77 16037 101 77.6 90 6/29/12 2112 77 16035 96 77.8 90 6/30/12 2119 76 16083 97 77.3 90 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\June\June 2012 ATTACH01.doc Exelkn.Exelon Generation Company. LIC www.exeloncorp.com Nuclear Byron Station 4450 North German Church Road Byron, IL 61010-9794 August 24, 2012 LTR: BYRON 2012-0094 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Spdngfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 110048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of July 1, 2012 through July 31, 2012.On 7/4/2012 and 7/8/2012 the U2 Natural Draft Cooling Tower (NDCT) basin overflowed as a result of plugging of the outfall screens caused by cooling tower fill pack debris. Operations took immediate corrective actions to lower the level in the flume and basin to stop the overflow condition.

Additionally maintenance personnel were called in the clean the debris from the outfall screens. The cooling tower basin overflow water flowed north in the storm water ditch and entered Woodland Creek via storm water Outfall 003, East Station Area Runoff. The estimated duration of the first overflow event is 5.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at a flow rate of approximately 20 gallons per minute resulting in an estimated 6,180 gallons of cooling tower water flowing through Outfall 003. Analysis results of a sample of the cooling tower water obtained prior to entrance into the storm water ditch are summarized in the following table: pH Copper (mg/L) Zinc (mg/L) Chromium (mg/L)8.69 0.010 0.016 <0.0021 The estimated duration of the second event is 3.0 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> at a flow rate of approximately 50 gallons per minute resulting in an estimated 9,000 gallons of cooling tower water flowing through Outfall 003. Analysis results of a sample of the cooling tower water obtained prior to entrance into the storm water ditch are summarized in the following table: pH Copper (mg/L) Zinc (mg/L) Chromium (m800.0 8.63 0.007 0.008 <0.0021 August 24, 2012 Byron Letter 2012-0094 Page 2 Byron Station continues to closely monitor NDCT debris fence delta levels and replacement of cooling tower fill is being planned. Unit 1 NDCT fill replacement is scheduled to begin September 2012. It is expected that the changes to the tower fill should prevent future tower overflow events.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Ben Pouma Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments bcc: J. Gould -Environmental

-Cantera (electronic)

Z. Cox -Chemistry

-Byron NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERFldTEE NAMEIADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvil,.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER I DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I A01-0 I I DISCHARGE NUMBER I MONITORING PERIOD MMIDDJYYYY

_J I MMIDDJYYYY DEMINERALIZER REGENERATE WASTE (001A)External Outfall 0." NO DISCHARGE FROMI 07/01/2012 I Tol 07/31/2012 Il lATTN: Zoe CoxIENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNS ANALYS TYPE S ld .T tlS s e d dSAM PLE ............

..... -<1.1 -0.2 19 0 01/30 08 Solids, Total Sseed MEASUREMENT 00530 10 oL. .Effluent Gross , , Chromium.

haxavalent SAMPLE Soo......(as Cr) MEASUREMENT

• 500-' .-4..... 2' '.?<" .=: -" ;r ,=,=Chromium, total SAMPLE ...... 500 (as Cr) MEASUREMENT 500 0103410 -s'ehrt JttQ~W~t .-(> H 2 -Effluent Gross x~~~t Copper, total SAMPLE ...... ......(as Cu) MEASUREMENT Soo 6-1~ .. at E Gross j _PUM'It:, -r"" . " v-} ..."".. .29 "'Iron, total MPLIE. ...... ...(as Fe) MEASUREMENT

.......__ "" " 600 Effluent Gross , ,_ ;. ..-, ,,r: +i, 0 Lead. Total SAMPLE ..........(as Pb) MEASUREMENT SIX 5 0105110 *V'iYflS 5!;5 .,"1"i : ; " -. 3/4, --" .Effluent Gross 1.- n;- 2 ;'%j s v:.Nickel. total SAMPLE .............(as Ni) MEASUREMENT 500 01067 1 0 : -l il ... --. ..... .... ... ....Effluent Gross n7i IJ,. .t- I.- ,. .NMIFTlLE I camfy undr penally of law tam tis document antd al atadmunents were prepared under my TELEPHONE DATE PvmIPAL .XECUiivE OFRCER aection or super4vson In accordance with a system designed to assure tum quaars personnel propeygahel and evalue da.tomation subsmed. BSwat an my mquiy of te person or peisons-Benjamin P. Youman who manage the system. or tose perssns dracay fr gaftht the infonration.

the 0/24/2012 Infonration sutmitted is.o the best oa my knowledge and beief, true. accurate, and Complete.

laIm SIGNA10E iSPRINCIPLE Plant Manager aware that tmere ae significant penalties for -sumi naIse lsformation.

iondudg tpoe psilyd EXECUTIVE OFFICER OR AREA wq aoA lne arid impAsiemlont tar knowing violatios.

AUTHORIZED AGENT MMODDYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed 31 o1 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 16/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEJADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warnnville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailign ZIP CODE.MAJOR (SUER 01) CS 61010 IL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER I MONITORING PERIOD I MMJDDIYYYY I MM/DD/VY DEMINERALIZER REGENERATE WASTE (001A)External Outfall I.. .FROM II 07101/12 70l I I ........07/3112012 i* * *NO DISCIIARGEEJ3..

Ia I~I NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DUR)PERMIT'EE NAME/ADDRESS NAME ExeloW Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 L0048313 PERMIT NUMBER B01-0 DISCHARGE NUMBER DMR Mailing ZIP CODE-MAJOR (SUOR 01) CS STP PLANT EFFLUENT (FORMER 001B)Exteral Outfall* * 'NO DISCHARGE 61010 MONITORING PERIOD MM/DWfYYY

-MM1DD/YYYY FROMI 07/01/2012 I TOI 07/31/2012 I PARAMETER I O- IQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE BO D , 5-Day SAM PLE 79090SI2 (20 Deg. C) MEASUREMENT 0.38 0.45 26 .7. 9.0 19 0 W= 24 0031010 8. a q 4 p~pH SAMPLE .. .... .O...pEASU N7.50T 7.53 12 0 02130 GR MEASUREMENT_____

___________

______ _____00o4oo010 o ' : ; ... ... -..:4. '-: Effluent Gross B --Solids, total suspended SAMPLE0.8.1 MEASUREMENT 008 0.12 26 cl.3 2.4 19 0 02030 24 0053010 .. .iA -§* -Effluent Gross 'A.Flow, in conduit or thru SAMPLE treatrent plant MEASUREMENT 0.005 0.009 3 ...... 0 01/01 CN 5005010 --. -,,. ---- .... -._ --__ ._ _ __. ..." .Effluent Gross ..."' -'" SAMPLE MEASUREMENT... .. .. .. ., ... ... ,. ... , :. ...:- --... : .. .SAMPLE MEASUREMENT-... ... .......SAMPLE MEASUREMENT NAML Enm.E i ceR C-f under penalty of law t0at thas document and au attaInmeints vwre prepare undet my TELEPHONE DATE P iAL EXECUtiVE OFFICER direction Of suPeAisin in accordance with a system designed to assure tha fied pemonnel TELEPHONE DATE ppewy gate and eve einlaittiabon suied. ased onmy Uquiry of the persmn or , 815 406-3700 02s0a Benjamin P. Youan "who manage th system, or those persons diety reansUbS for gathering tme iormati. the c=-2112 irdonation submited is. to the best di my knowiedge and bein,. true. accurate.

and c*mgtte. eam SIGNATqEOF*INCIPLE 0&24/2012 Plant Manager aware at tere are sincant penaties t1 submitting t21se WConaM. ndudcng the powAi, y ci EXECUTIVE OFFICER OR AREA.m ,ie and bpisinnen for mowing vicilizons.

4________________

iwn out anfomu AUTHORIZED AGENT CODE_ NUMBER MI&DD/YY__

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Refereme all attachments hem)1. Flow exdsted though this outfall29 of 31 days dunng ft month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/12 PAGE 1 S NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMI7TEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER I MONITORING PERIOD MMIDD/YYY i I UMD YYYY WWTP (FORMER 001C)External Outfall*.. NO DISCHARGE FROMI 07/01/2012 I TO I1 07r31/2012 I-I .lATrN: zoe Cox/ENv SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY AMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids, total suspended EAUMLE ..... ...... 4.3 7.2 19 0 02/30 24 Effluent Gross Chromium.

hexavalent SAMPLE ........ ..(as Cr) MEASUREMENT 0103210 *Effluent Gross X Chromium, total SAMPLE ... ......(as Cr) MEASUREMENT

....... ..._500 0103410 Copper, total SAMPLE ..........

..(as Cu) MEASUREMENT EffluentGross

..Iron, total SAMPLE ....S (as Fe) MEASUREMENT Effluent Gross Lead, total SAMPLE .. ...(as Pb) MEASUREMENT 01051 IE~I' W-; '" ..' "- -- ..." "* ' .." " ..;Effluent Gross -rf,, ..:;. Nickel. total SAMPLE ............

.(as Ni) MEASUREMENT

.... 500 010671 0 AEjgT Effluent Gross W*O- __NAMEITLE I certiay under penalty of law that this document and all attachonmr were prepared under my TELEPHONE DATE PRIPAL EXECUTIVE OF1CiER direction or Supemlon in accordance with a system designed to assure dtoa quaified personnel a tpopedy gather and evyee the formaon submted. Based on

-ateerson ,. 815 1s406-3700 0 Benjamin P. Youman who manage me system, or those persons dircy responsible for gatlheing the infonmsaon.

me 40=4/2012 inaomaton is. to the best of my kroledge and be"et true, accurate, and complete.

I am __GNA___O___R_

_PLE Plant Manager awar t them are siWgma penalties for submittng false information, Inuding the posslift EXECUTIVE OFFICER OR AREA NUMBER MMfDD/YYYY 1nMMORPLOw ne and imprexnad ot ,knowing vicions. AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outfall 25 of 31 days durng the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 116r2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMWTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvile.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road I DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 S R NIL0048313 PERMIT NUMBER I I C01-0 J DISCHARGE NUMBER I [D ISCHARGE NUMB3ER 1 MONITORING PERIOD MMIDD/YYYY I 110YYYY WWTP (FORMER 001C)Extemal Outfall* NO DISCHARGE EJ'FROMI 07/01/2012 ITOI 07/31/2012 I Byron, UL 61010 AT TN : Zoe C ox/EN V S PEC FR EQ U EN C Y QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Zinc, total SAMPLE....

.....(as Zn) MEASUREMENT Effluent Gros .s;-G Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT s005010 '77-',, P .-..M, .. -_. .. ;-- * .Effluent Gross SAMlPLE MEASUREMENT

' A.SAMPLE MEASUREMENT jx.. ,v-1 SAMPLE MEASUREMENT SAPLE SMEASUREMENT SAMPLE.MEASUREMENT KAME nlTM.E Icertify under penalty of law duda On documnent and aU s were'lX'eBmor under my TELEPHONE DATE PRINCPAL EXECUTIVE OFCF.R dimaiu or supeamso in accorden, weith a system designed to assure goi Wuaffied pg ofne-prope* gather and evakute th'le Information submitted.

eased an my inquir of the person or Persons ..-J, 85 0-70 Benjamin P. Youmnan whto 11a998 the systun, or those persofsdnsif rme sponsiD for 9111116 the Woeat"t, uthe 41 6.L 0700612412012 information sub~mitte is, to the best of my knowledge and belief, true. accurate.

and *ompiete.

I am iGINIAVEIi OP1#RINCIPLE P la nt M ana g e r aw are ta m there a re significant Pe aJ ties for sub fla se in orai on, U ftud f t hle po l of E X E C U T IVE O F FIC E R O R A RE ...a POINTE Pine and imrsomn for knowing violatfions.

I AUTHORIZED AGENT [CODE NUMBER MM/DD/YYYY COMMENTS ANn EXPLANATION OF ANY VIOLATIONIS (Reference all attachments here)EPA Form 332D-1 (Rev 01/06) Previous editions may be used. 1 1/6=12 A%L W NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM {NPDES)DISCHARGE MONITORING REPORT (DUR)11L0048313 DO1-0 PERMIT NUMB8ER ý DISCHARGE NUME I MONITORING PERIOD PERMIlrEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road O DMR Mailing ZIP CODE: 61010 MAJOR (SUBR 01) CS RADWASTE TREATMENT (FORMER 001 D)External Outfall* **NODISCHARGE l -.-- I FROMI 0710112012 I Tot 0713112012 I------------Il e Byron, IL 61010 ATrN: Zoe CoxiENV SPEC ____ ________ _________

__________

AQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. SAMPLE PARAMETER EX OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Solids, total suspended MEAMPLENT

.... .4.5 4.5 19 0 02130 CP Effluent Gross "24., m ,,.-. ,z, .....Flow, in conduit or thru SAMPLE........

tre a lm e n t p la n t M E A S U R E M E N T 0 .0 2 3 0 .0 2 3 0 Effluent Gross *WTW'r. ,;t. W%. j" ..,7 SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT

.77=" 1l81MM, A' M u&n SAMPLE MEASUREMENT 4;' %~ ~dv '?~W~ ~ u~!2A+ *Z-~..- ~3/4yA~~4,~.....

~ NAME/IITLE I ceanty uade pennyt l law that me domnent and at, alacmetmei were pared ucnde my TELEPHONE DATE RNCIPAL E.XECUTIVE OFCER direcon r supeivse mn acwodance wdi a system des9ged to surm that qualfed personrnl properly gather and evatke We mfomiatim subnled. Based an my hnQuiy of Ve person n pereata Benjamin P. Youman who mnage me sysmemy o those Persons ar,,ty rsporae fo gathen te Worman the 0824/2012 Wwito Is. to th be of mhy an 00. true. accrat. an ýý Iam SM=.N R 0 O CL"LE Plant Manager aware do there an sogratam penats fto subitbTag ae bainaatln,m bmdm L Wthe P S EXECUh1JEfqGCER OR AREA" nca. mn fs din and rapusonment tor lontoag violaaom AUTHORIZED AGENT CODE NUMBER MMIDDJYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (RAefOerce all attachments here)1. Flow exdsted through this outfall 10 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11W2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvile.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER DMR Maeling ZIP CODE: MAJOR (SUBR 01) CS STORUWATER (FORMER 001E)External Outfall***NODISCHARGE j *61010 MONITORING PERIOD f MWDDIYYY I 11MJDDI113YYYY FROM II 07/01I2012 I ToI 07/31/2D12 I-I !RE Itd £J Or-'1.. _____FRE_______UENCY______

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. F SAMPLE PARAMETER EX TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Solids, total suspended SAUMPE ..... 8.1 8.2 19 0 01/07 GR Soids, total suspended MEASUREMENT 0053010 zi"&Other Taatment, Process .A"" "" Complete Chromium, hexavalent SAMPLE ....... ...(as Cr) MEASUREMENT 0103210,'..<..

! .' Chromium, total SAMPLE ...... ......(as Cr) MEASUREMENT 0103410 I' t.1 .-' .. -.,-,- ... ..'"' : ',. :P, "' , Copper. total SAMPLE ................(as Cu) MEASUREMENT Effluent Gross F. ..at..... "* : .Iron, total SAMPLE .............(as Fe) MEASUREMENT_________________

_______ _______________

____Lead. total SAMPE ....... 500 (as P1) MEASUREMENTr________" __________

__-________

......._.___ -________'_______j -Effluent Gross NMEITTE I catr*y under penaty of law that this document and aln attachmanes were prepared under my TELEPHONE DATE PRIACIPAL JECUTMVE OFFICER d&ection or supernstion In accordance with a sytam dasrgned to assure that qutfifd personnel prory gather and evalsa moemon saurmitaed Based on my nquy the Perso or pemns 815 406-370 Benjain P. Youman who miu, a te system. or thse piusan diectly r t gathe" me htonnado, te 08/24/2012 Intomation subrmittd

i. to the best ol my imowledg and baele. true. accurate.

aWd complete.

am SIGNAIsuRE OuVtuRCIPLE Plant Manager aware that them are sinifcan penaltes lor tsubtn lawe IWouion. Incudking Me possily of EXECUTIVE OFFICER OR AREA owan oPn -I rum ad nctlsionmemn lot violaft. AUTHORIZED AGENT CODE NUMBER___________

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow e)dsted through this outlall 4 of 31 days during the month.EPA a 1 (Rev 01106) Previous editions may be used. A 1/6/2012 El L -W W NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DUR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road WarrenviWle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 OUR Mailing ZIP CODEO MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER IMONITORING PERIOD UMIDDIYYYY MMI/YYY STORMWATER (FORMER 001E)External Outfall***NODISCHARGE FROMI 07101=212

-_ITOI 07/31/2012 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER EX OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Nickel. total SAMPLE ...... ...500 (as Nil MEASUREMENT Zinc. total SAMPLE ......S..o.." (as Zn) MEASUREMENT_____

_______________

01092 1 0 A-. , .-* , .. ....--.., -" " Effluent Gross C -.1s --Pft .-g Flow, in conduiLt or thru SAMPLE 0 0 020 CN treatment plant MEASUREMENT 5005010 V'Pt...~~o.~.

Effluent Gross , .: SAMPLEn MEASUREMENT

• °~ ~ ... .. .. ....A

• c... ........., 41( 1L Ak _SAMPLE MEASUREMENT SAMPLE MEASUREMENT

/SAMPLE MEASUREMENT I"n M ngr wr tha there are :.* "infcn pe ..t.e ta ..ub-mitti-g ta ,e ,itor '.ion .trukgte eatt EXEC""UTI'-

-':-.. OR.. A"" R NUMBER .... ... .NAMENTSLANE I CeETy under penaNty VI O aw aO NS (Rfumemrnd ld attachments here p)a InWormy TELEPHONE DATE P iNoIPAL EXECUTWE OFFCER dinctian o in acroance with a system dwas to dsshre aged quhim personhl pmpely gter andevaue meatw~ nsubmtt. Be a n y m par o te pemn opesmms , =[ _ 815 4o 700 Benjamin P. Yournan who manage me system, or amoe peman dhcty nesparw for gavedo die kdormu. Me 08/24A2012 Vdannto submitte is., to di be d myknwlde an be, tru., ac.,m , an cwnpl. Iam NJ R% 0F P CIP LE Plant Manager aware ghatthere am sodfic= pen,"fmsubmttin tabsn Womeatio.

ftd to posrsyf cl EXECUTIVLOQPCER OR AREAl UBRM/DYY Tymopm -I fine and kmrisamnmt tar Wxming vk~ladn. I AUTHORIZED AGENT CODENUBRM/OYY COMMENTS; AND E:XPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Generic Non-Chemical Metal Cleaning wastewater was discharged this month.2. No Frue Protection drain water was discharged this month.3. Turbine Building Fire and Oil Sump wastewater was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/212 PAGE 2 1121 PG NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEIADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Wanenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road I OUR Mailing ZIP CODE*MAJOR (SUDR 01) CS 61010 I IL0048313 I I 001-0 I PERMIT NUMBER DISCHARGE NUMBER Il ![ MONITORING PERIOD&MM/DD/YYYY -j I MMIDW/YVYY COOLING SYSTEM BLOWDOWN Extemai Outfafl* NO DISCHARGE FROM I 07/01/2012 07/31/2012 I Byron, IL 61010 ATTlN: Zoe Cox/ENV SPEC ______________

___________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE Temperature, waterdg SAMPLE ...... 103.0 0 01/01 CN Fahrenheit MEASUREMENT 0001110- &c -.<% t,-s* *W4l-Effluent Gross pHAMPLE ...... 828 8.73 12 0 01/07 GR pH ~ MEASUREMENT Effluent Gross -~ 9 * .' t SAMPLE ..... 3.0 3.0 19 0 01/30 GR Solids. total suspede MEASUREMENT 0053810 Prj1j11 LA, -.~6" 4~ 4 PQWflz i .~'Effluent Gross A Mgaafi SOil & Grease cAA -..4 19 0 01107 GR 00&GaeMEASUREMENT 0*1 -10 Chromium, Gtaro (as Cr) MEASUREMENT

-'tV.-ry,,'-:, '"° .-, " *,', ". ';Capper, total (as Cu) A E0021 19 0 0107 OR Effluent Gross MIn: 1 r i iL U h h: iCope, total (as Cu) SAMPLE ...... .......002 9 a 0WG Zinc.Mtotal (as.Zn)SA

<0.0027 0.0042 19 0 01/07 GR Effluent Gross 0 4t 1! tNME/llTLE I cerly under enafty al law Wm it document and all atachMars were PreParea under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER dfrec or supenuswn in accordance wuh a System designed to assure da quarlied personnel papofny agerand evatue ve Innmmam ubite. B ae onmyinquiryof te pason Wpersons T" bk 815 4:0r-3700 N 21 Benjamin P. Youman who manage de system, or mose persmn dlmc responaAe (or gadin eng die hdml. die2201 Infomnatin

&e&nMed is. to the bess of my WicAesege an be[, inue, accura andi complee. Im en GNAt-J RINCIPLE Plant Manager aware di tdniem am sivfca penales for summlig lalse binttlii hcktt idu ft e pstity 0 EXECUTIVE OFFICER OR NUMBER MM3DD/YYYY WDn 9 f bn and hntfme fr OMn v AUTHORIZED AGENT CooD COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Monitoring data for outfall 001-0 is Included on attachment EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1"/201= 1PAE 1 S S 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 001-0 PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MWIDIYYY I I MWIDIYVYYY PERMITrEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winetld Road Warrenville.

IL 60555-5701 FACIUTY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTN: Cnx/FMU RPI=r WMR Mailing ZIP CODE. 61010 MAJOR (SuIBR 01) CS COOLING SYSTEM SLOWDOWN Extaenal Outllt***NO DISCHARGE FROM L 07101/2012 I TOI 07/31/2012 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION No. OF AML PARAMEER OF SAMPLE RMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Oxidants.

total residual SAMPLE0.04 19 0 07 GR MEASUREMENT Effluent Gross ,. .- l Pdouity pollutants total effluent SAMPLEMENT...

MEASUREMENT

""SIX0 Effluent Gross a. m -.. .. ._ _ "ltl :!Flow, in conduit or thMm SAMPLE treatment plant MEASUREMENT 20.99 2827 3 0 01101 CN E ffluent G ross & 4e.--.'T-Chiaorti.

total residual SAMPLE ...........

MEASUREMENT SIX 81 1 1 --, * ....-.. .. .. ... ..... ..Effluent Gross 9 .... a U .'Hydrazine SAMPLE .........MEASUREMENT 500 SAMPL MEASUREMENT SAMPLE MEASUREMENT PR"CUAL E.MC OFRCER rifectmin or superein i accordance wfm a systemn desow to assure oiawaec pann TELEPHONE DATE Benjain P yo gan 91018 and evafija the Womntciazg subaienld.

Based an mvy mcpfty ofte person at peansa, ~Ck 815 406-3700 Benjamin P. Youman wo manage me system, or mose perons directly responsaft for gawtlg me "iatlm me S AA0&24/M012 Plonmt Min g s1 i la t Wl is. to he best do c oy kno wad e and b "e .m.. acon t , and co roete. Ia m EXEA I! , E O FaICmE Plant Manager ausare that th are sinkn penatbe for absbglahz aa ifmtumao Incmeg me pcaauizy o EXJECUTVE OFFICER OR AF ao mnr , .AUThO:RIE AGENT Cfet NUMBER MMIDD/YYYY TWO UM fine and

• anan tafr knwyviolations.

________________

AGENT_____CODE__

COMMENTS AND EXPLAATION OF ANY VIOLATIONS (Reference a attachments hem)EPA F6oM 3320-1 (Rev 01106) Previous editions may be used. 1111=12 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvilie, L 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road I I L0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUlR 01) CS STORMWATER RUNOFF BASIN External Outtell"NO DISCHARGEE J 61010 MONITORING PERIOD MM/DD/YYYY I I MMIDDWYYYY

! I I Il .....FROM I 07/0112012 IToI 07/31/2012 I j I Byron. IL 61010 ATTN: Zoo Cox]ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE ,, VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANA TYPE SAMPLE .........

... .......Solds ToaiS~sened MEASUREMENT____

_______ __________

Effluent Gross A Solids. Total Suspended MSASUEMPLEN 003Other Treatment8 Process :.!III :" ...... ... .,, ..:" .. ..Comolete it AM~ k '.<:~ 'i-Chromium, hexavalent SAMPLE ......(as Cr) MEASUREMENT Effluent Gross " ... .Chromium, total SAMPLE ................(as Cr) MEASUREMENT 0103410 :' W _ ..2 ;:: Effluent Gross RIM ..________.,_

--_ " Copper. total SAMPLE ............

...(as Cu) MEASUREMENT Iron. total SAMPLE ..... ......(as Fe) MEASUREMENT 010 51"0 Effluent Gross L .,. -.:. ,_._.... ,7.5. .-Lad., total SAMPLE ...... ...(as Pb) MEASUREMENT

"________ " __"""_*_ .r_*_._. _ _ ..... -.__--.._,_..

..__I M.LE .E OFU I cany Uinder penalty of law that tah document and ao attachuents were prepared under my DATE PdiNCtPAL EUTIVE OFFIC tiR on or supe-rsi in accordance with a system desiogad to assure that qualifind persinnet TELEPHONE DATE Benjain P.Yournn wprpely gather anld evelute the intomnatio submte. Sasen my incluiry of the person or persons_0

_4V30 Benjamiwn P. Youman etto manage systenm. or thae Persons directv reapolse for gathenng the Inomionme..

the 0824/2012 m oam atim sutbn ited Is. to the best d my nW oote dge a r , i glae. .sc u m s. and compete. IJam SIG XA .LR F LE 'F Plant Manager awanrieat nther are signiricant penaties for suMittng labse bonnaon, bicuding te possaiby of EXE~CJTIVE OFI OR AR MY andD anmonet 1wOM NUMBERg violatins__sw roe and! buusnunt for blow ng AUTHORIZED AGENT CODo NUMBERM _ ____ ____COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. No Turbine Building Fire and Oil Sump or Genetic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form201 (Rev 01/06) Previous editions may be used. 11612012 W i L -

0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)OUR Mailing ZIP CODEt MAJOR 61010 PEMITT`EE NAMEADDRESS NAME Eaton Generation Co., LLC ADDRESS 4300 Winfield Road Warenvi,, 06055-5701 FACUIY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, L 61010 1Ar=Ka* 7,.P eCUccr-IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER (SUBR 01)CS MONITORING PERIOD MM/D"/YYYY I MMIDYYYY STORMWATER RUNOFF BASIN tal Outfall* *NO DISCHARGE M FROM I 07/01/2012 I TOl 07/31/2012 Il lQUANTrIY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARMETER ..OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Nickel, total SAMPLE ............(as N) MEASUREMENT Effluent Gross Sig = 4--ý. ..Zinc, total SAMPLE , ., (as Zn) MEASUREMENT 0109210 ,. -jr ... -.Effluent Gross , .; , , ,. ..,. .-Oil aGeasSAMPLE Oil andGreaseMEASUREMENT

____ ____ ____ ____035 2 1 ........ ..Flow, in conduit or thru SAPL ...... --tetetpatMEASUREMENT

____________________________

____ ___Effluent Gross Rowm cndui

.........MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENTNMEM I caddy under penalty ol law at thUs documen and al atucnants were prepared undeo my TELEPHONE DATE PRWNAM EXECTNE or supenhi I with a system designed assure dMt quafied! personnel preped gather and evabia tea bdnfonatimgsubmitted Basd an my bquury ofMe person or persons ~ ja gy ,062/2 Benjamin P. Youman wo maonage th system or those pemons dncoy respwisae for gamefg the Itmnatan.

the 0W24/2P12:mfonato submittd is. to the best of rny kiowleOe and betel. hue, &=crfand omplete. Iar SIGN= OFZ CIPzz=Plant Manager aware gs tere ar sipfcant penaltes fo SLt'rmo false Ifonaran.

Induftg te M W Y EXECYEO YYOR noRM pns and Ca b AUThORIZED AGENT COO NUMBE MMIDD/VY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hav)1. This discharge point was not used this month.2. There was no discharge o processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 011M) Previous editions may be used. 116012 PAGE 2 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 July 2012 Page 1 of 3 MONITORING DATA: CWBD Rock RIver DATE Temperature CW gd Flow deg F cfs 07/01/2012 99.0 22.04 2,130 07/02/2012 101.0 18.63 2,120 07/03/2012 101.0 24.02 2,080 07/04/2012 102.0 17.52 2,040 07/05/2012 102.0 20.72 1,990 07/06/2012 102.0 19.99 1,880 07/07/2012 102.0 24.39 2,010 07/08/2012 101.0 14.60 1,920 07/09/2012 96.0 12.80 1,790 07/10/2012 95.8 18.91 1,770 07/11/2012 97.0 18.21 1,800 07/12/2012 96.4 17.75 1,780 07/13/2012 98.0 23.14 1,770 07/14/2012 97.7 25.89 1,760 07/15/2012 99.4 22.63 1,850 07/16/2012 101.0 15.86 1,750 07/17/2012 102.0 25.27 1,780 07/18/2012 102.0 19_.07 1,730 07/19/2012 100.0 22.15 1,980 07/20/2012 100.0 21.85 2,010 07/21/2012 95.0 27.78 1,990 07/2212012 99.6 25.38 1,920 07/23/2012 101.0 15.15 1,840 07/24/2012 103.0 21.70 2,060 07/25/2012 102.0 22.94 2,070 07/26/2012 102.0 21.17 2,000 07/27/2012 97.6 20.88 1,930 07/28/2012 96.3 29.27 1,940 07/29/2012 98.0 21.98 1,950 07/30/2012 98.0 15.87 1,940 07/31/2012 101.0 23.01 1,950 0 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\July\July 2012 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 July 2012 Page 2 of 3 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of July 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 29.2 mg/L on 07/09/2012.

The CWBD TSS value was 3.00 mg/L on 07/09/2012.

5. Rock River flow was <2400 cfs in July 2012 therefore daily temperature calculations were required during this time period. (Special Condition 12).Per Special Condition 12, in the event the Rock River flow is <2,400 cfs, daily calculations will be undertaken to demonstrate compliance with the water quality standard.

The calculations are based on hourly measurements, averaged over a 24-hour calendar day for Rock River flow, main Rock River temperature, CW Blowdown flow, and CW Blowdown temperature values. Results of the calculations shall be reported in the DMR on a monthly basis. Calculation results are in the table on the following page.6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in July 2012. (Special Condition 15).K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\July\July 2012 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 July 2012 Page 3 of 3 Date Average Average Average Average Calculated Water Quality-Rock CW M/U CW CW Temperature Standard River Temperature Blowdown Blowdown at edge of Temperature Flow (F) Flow Temperature mixing zone (F)WcS) (gpm) (F) (F)7/01/12 2,123 78 15,830 98 79 90 7/02/12 2,124 80 16,221 100 80 90 7/03/12 2,088 81 16,208 99 82 90 7/04/12 2,040 81 14,777 101 82 90 7/05/12 1,999 82 12,686 102 83 90 7/06/12 1,875 84 13,113 102 85 90 7/07/12 1,987 84 12,675 102 85 90 7/08/12 1,938 83 12,059 96 83 90 7/09/12 1,807 81 12,293 97 82 90 7/10/12 1,770 78 13,375 96 79 90 7/11/12 1,802 77 13,411 97 78 90 7/12/12 1,781 78 14,590 98 79 90 7/13/12 1,775 78 15,685 99 80 90 7/14/12 1,752 77 15,525 99 79 90 7/15/12 1,850 80 15,433 101 81 90 7/16/12 1 758 83 15,565 101 84 90 7/17/12 1,774 84 15,449 102 85 90 7/18/12 1,731 85 15,736 101 86 90 7/19/12 1,964 83 15,658 97 84 90 7/20/12 2,010 80 15,688 95 81 90 7/21/12 1,995 81 15,828 96 82 90 7/22/12 1,927 80 15,778 98 80 90 7/23/12 1,835 79 15,749 100 80 90 7/24/12 2,050 79 15,805 100 80 90 7/25/12 2,082 79 15,676 99 79 90 7/26/12 2,003 78 15,550 98 79 90 7/27/12 1,940 78 15,500 96 78 90 7/28/12 1 941 77 15,390 95 77 90 7/29/12 1,998 76 15,493 95 77 90 7/30/12 1,945 76 15,386 98 77 90 7/31/12 1,952 78 15,499 99 79 90 0 K:\BYR_CHXBYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 ReportsJulyUuly 2012 ATTACHO1.doc Exelkn,.Exelon Generation Company, LLC www.exeloncorp.co0,,.

Nuclear Byron Station 4450 North German Church Road.Byron, IL 61010-9794 September 25, 2012 LTR: BYRON 2012-0106 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of August 1, 2012 through August 31,2012.On 8/9/2012 the U2 Natural Draft Cooling Tower (NDCT) basin overflowed as a result of plugging of the outfall screens caused by cooling tower fill pack debris. Operations took* immediate corrective actions to lower the level in the flume and basin to stop the overflow condition.

Additionally maintenance personnel were called in to the clean the debris from the outfall screens. The cooling tower basin overflow water flowed north in the storm water ditch and entered Woodland Creek via storm water Outfall 003, East Station Area Runoff. The estimated duration of the overflow event is 63 minutes at a flow rate of approximately 0.13 gallons per minute resulting in an estimated

8.3 gallons

of cooling tower water flowing through Outfall 003. Analysis results of a sample of the cooling tower water obtained prior to entrance into the storm water ditch are summarized in the following table: pH Copper (mg/L) Zinc (mg/L) Chromium (mg/L)8.39 0.014 0.044 0.004 On 8/30/2012, cooling tower water was seen coming out of the storm drain pipe located next to the U2 NDCT. The water had pooled on the ground and run underneath the barrier erected around the storm drain pipe to prevent this from happening.

Maintenance personnel adjusted the catch containment devices for the temporary Mechanical Draft Cooling Towers which were the source of the pooling water. This stopped the flow of water entering the storm drain pipe.After walking down the area it was determined the water had pooled at the storm drain pipe exit and had not entered the drainage ditch nor exited via Outfall 003. The estimated duration of this event is approximately

2.0 hour0 days <br />0 hours <br />0 weeks <br />0 months <br />s

at a flow rate of approximately 0.5 to 1.0 gallons per hour resulting in an estimated 2 gallons of cooling tower water entering the storm drain pipe.Analysis results of a sample of the cooling tower water obtained prior to entrance into the storm drain pipe are summarized in the following table: Copper (mg/L) Zinc (mg/L) Chromium 0 (mg/L)0.029 <0.0020 <0.0021 September 25, 2012 Byron Letter 2012-0106 Page 2 Byron Station continues to closely monitor NDCT debris fence delta levels and replacement of cooling tower fill is being planned. Unit I NDCT fill replacement has started as of September 2012. It is expected that the changes to the tower fill should prevent future tower overflow events.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Benjamin P. Youman Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments bcc: J. Gould -Environmental

-Cantera (electronic)

Z. Cox -Chemistry

-Byron NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMrl-EE NAMFIADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC DMR MaIlIng ZIP CODE.MAJOR (SUBR 01) CS 61010 I IL0048313 It A01-0 DISCHARGE NUMBER I PERMIT NUMBER q i B DEMINERALIZER REGENERATE WASTE (001A)I External Outfall I MONITORING PERIOD i MOIDDJVYY I TO MMIDD/YYYY 1 FROMI 08101/2012 08/31/2012

• *

• NO DISCHARGE E ...PARAMETER QUANTITY OR LOADING VALUE VALUE UNITS VALUE Solids, Total Suspended MEAMUREENT

..0053010 PERMIT-Effluent Gross REQUIREMENT.

_ _, "_.* ..Chromium, hexavalent SAMPLE ...(as Cr) MEASUREMENT 010321 0 PERMIT ..,.Effluent Gross REQUIREMENT , .Chromium.

total SAMPLE ... ...(as Cr) MEASUREMENT 0103410 -PERMIT-Effluent Gross RIEQIWREMENT

_ ... .. --Copper, total SAMPLE ...... ......(as Cu) MEASUREMENT 0104210 .. PERMIT .-.**.. .., Effluent Gross REQUIREMENT I_..... ..-Iron. total (as Fe)010451 0 Effluent Gross SAMPLE MEASUREMENT

.-PERMIT, REQUIREMENT

• ": :....., ...Lead. Total SAMPLE ...... ......- ..(as Pb) MEASUREMENT 500 0105110 PERMIT " -..2 .4 Effluent Gross REQUIREMENT 3AVG DALY"MX* _ *4, *3D AG D L M ..1 NICkel, total (as Ni)0106710 Emfuent Gnros OAMPLE MEASUREMENT ,e-. -. -_ ... --.,.. ... ... ...... .. -.-.I ... , r~ain -*."i ." eeeemm.........

....... .... ... _ _ _ _ _ "" " ." "1" ....... ... ...i W ARIEn T TLE I certify un de pena lt dl law duda h is docum e nt an d al attac h mn t we rem p repare un de m y T E L E P H O N E D A TE P__ _ ___AL EXECUTIVE OFRCER diretio of supervio in a=oft= wit a system designed to assure that quakted personnel properly gather and evalute site ubmittted.

Balsed at my inquiry of the persa or persons 815 406-3700 Benjamin P. Youmnan who manage the system. o those persons directly respaltbla for gathering the bttomatxe.

the 09/25/2012 Infomation submed is. to the best d1 my knowledge and befef. true. acjrate, and contelete. ,am, SIGNAV E OF PR IPLE Plant Manager aware hat here are significant pensitles fo submitting tslse kitnfoaI, inducing the of EXECUTIVE OFFICR OR AREA NUMBER MM/DDIYYYY o_ N b n Ie and impilsionmner for knowing violations.

AUTHORIZED AGENT CODE N B__COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments heme)1. There was no discharge of processed steam generator chemical cleaning wastewater during fths month.2. Row existed 31 of 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116,2012 PAGE 1 S NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 DMR Mailing ZIP CODE: MAJOR (SUOR 01) CS 61010 IL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD MMJDDJYYYY MM(DDIYYYY DEMINERALZER REGENERATE WASTE (001A)External Outfall"**NO DISCHARGE

[ ...FROMI 08/01/2012 TOIl 08/31/2012 I I IIl I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREOUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS Zinc. Total SAMPLE .. 500 (as Zn) MEASUREMENT I____0109210 puur -12. 'Effluent Gross REQUIREMENT

.00 V DAILY LIX G Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT 500501 0 PERMIT'.-'

Req. Mon., *" -. -Effluent Gross REQUIREMENT 30DA AVG DAILY MX * -D* ; ...tT SAMPLE MEASUREMENT PIBRMW .............

..-.... I" ". "...-"...:.:

.".** ., ..'.-....- '." .." .,-.',./':,-..1.-.....-" REQUIREMENT

._ __"__'_ _"_....SAMPLE MEASUREMENT PERMI REQUIREMENT

... ." --SAMPLE MEASUREMENT PERMIT -... .: ...,7' .-, .". .. ., ii ...-.-- .^ ,. .. ..,- -* i .. °': .: ...* ..... ...REQUIREMENT

......._._"_* _ ' .I'"___.. .SAMPLE MEASUREMENT PERMT REQUIREMENT

___SAMPLE MEASUREMENT REQUIREMENT

_ _ _ _"_- " -" --NAMF..TLE I certify inder penafty d taw thal fts docmment and all attadnients wmer prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER

• aon W SupemWM In ac=orance with a syWtm designed to mWuM that quafifed per-onns prapert gather and evakie the inonii sutieni Based an my inqufy of Me peisan or persons 854-30 Benjamin P. Younan who manage the system. or thw persora dcrectly responsilits for gathering the Ifonnatcn, the /212 infonnarm rnsutirnied is. to the best df my Imowledge and belef, trie. acc,-ate.

and cornpelte.

i en OF PR CIPLE Plant Manager aware that here are sencant penalties ublnit, fablseowmalnm bmcbng te posshfy EXECUTIVE OFFICER OR ARUA TY*PE OR rH E 0nd P D iolatonsw AUTHORIZED AGENT COD MM/DD/YYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reftrence all attachments here)1. Flows for August 2012 are estimated based on July 2012 values due to totalizers being Out of Service in August The totalizers are an obsolete model and work orders are in place to find replacement totalizers and get them installed in the system.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 11A12012 PAGE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Wintfild Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER B01-0 I DISCHARGE NUMBER I MONITORING PERIOD I MMIDDIYYYY I I MMIDDJYYYY STP PLANT EFFLUENT (FORMER 001B)External Outfall-"" NO DISCHARGE C]" I _ .I! ._FROM Il 08/01/2012 ITOI 08/3112012 I I I!Byron, IL 61010 ATTN: Zoo Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX A Y TYPE>< ANALYSIS BOD, 5-Day SAMPLE (20 Deg CAME 0.38 0.40 26 6.5 7.0 19 0 02/30 24 (20 Deg. C) MEASUREMENT E l n G N .O A.. f,: > .-DA AV G.- flAY X l. , -e ..... C.t .P24.:' ....-. --0 'pHSAMPLE 7.41 7.61 12 0 02/30 GR MEASUREMENT 0040010 -PERMIT' 7 ~ 7~- rr V -S Effluent Gross REQUIREMEN

...- ~ ~ MINIMI.M 4' ---.MA______ -. _____Solids. total suspended MEASUREMENT 0.063 0.080 26 <0.78 1.2 19 0 02130 24 0053010 ~ PERMIT:. soT 77ki~ ..~ -.'.-. I Effluent Gross REQUIREMENT

-"DA AVG. ,'"' AVG 301/2LY:MX C -Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT 5005010 .... " p , .' e- o.n.' " Req..Mo.rr., 7. , ' " " '. .. .. -' -..--: Effluent Gross REQUIREM.T

.301A AVG -DAILY MXM.:g-/..

." '. -- .. -+ .. .. .t ° .,C SAMPLE MEASUREMENT PERMIT SAMPLE- --,SAMPLE MEASUREMENT

• PER1M1NT 777... -" '77 7'-'SAMPLE MEASUREMENT NAMElTTLE I ceitly under penalty of law that tsie document and all atlacdunants were prepared under my TELEPHONE DATE EXECUTIVE OFFCER diectin or supesviei in acomdance with a system designed to assure pemownn properly gather and evadute the Wlnonnaion submitted. Qulymo the per= or pereons , U(:,,,, 815 406-3700 Benjamin P. Youmnan wrto manage the system, or amse pesais diec* responsUbe lot gathietig Ste ndonmatia.

tMe 0925012 bnomain suteittd I. to the best of my knowledge and beliel. true. accurate, and complete.

I am SIGNATURE OF IICUPLE Plant Manager aware that them am signfcard penallie for subimittIng labsa infonnation, ft of EXECUTIVE OFFICER OR AREA TWINEnPe raeand biroeiment norn knoi ong violatlWI AUTHORIZED AGENT CODE NUMBER MM/DD/_YY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hers)1. Flow existed through thi outtai 29 of 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. I1A/2012 PAGE 1 0 S PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 0 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 I PERMIT NUMBER C011-0 DISCHARGE NUMBER MONITORING PERIOD MM/DDIYYYY I I MM/DWIYYYY DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS WWTP (FORMER W1iC)External Outfall* *

• NO DISCHARGE j *J 61010-- ---- 4 I I FROMI 06/01/2012 I TOI 08/31/2012 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Soids.totalsuspended SAMPLE 5.5 7.1 19 0 02/30 24 MEASUREMENT Effluent Gross REQUIREMENT

-0DA AVG DAILY MX.Twice1,er.Month.C-IX#A Chromium, hexavalent SAMPLE 500 (as Cr) MEASUREMENT So-0103210 PR -*... .,,..'Effluent Gross REQUIREMENT DDALY MX mgI -,--DaAly:..;.

R Chromium.

total SAMPLE A AV....(as Cr) MEASUREMENT

...... 500 0103410 PERMIT" -." -1 2 -.Effluent Gross REQUIREMENT:-_._:.__.

30DAAVG DAILY MX Copper, total SAMPLE ......(as Cu) MEASUREMENT Soo 0104210 .-PERMIT' 1 -.Effluent Gross REQUIREMENT G -..- "OD A.:AL ."Da, ,RAB Iron, total SAMPLE 5 (as Fe) MEASUREMENT So-0104510 PERMIT , --'Effluent Gross REQUIREMENT

-__ _ _ _ " .." _. " _"'__ .._ ._."_:_OD LY MX "m11. Daily. GRAB Lead, total SAMPLE (as Pb) MEASUREMENT 500 0105110 PERMIT A.. --.2 A Effluent Gross REQUIREMENT 3"DA .-.SOA AVG DAILY MX mgDL .* GRAB " Nickel. total SAMPLE ...... ..........

..500 (as Ni) MEASUREMENT 500 0106710 PE.' .... 1 2 Effluent Gross REQUIREMENT

-_"_ " "_ 3DA AVG DAILY MX mG.AB NAMEITTLE I ceu* under penany d taw that this documen and ,an attachments were pepard undw my TELEPHONE DATE PRNPAL M CUV OFFICER o :luimcn or supemin In accmdance with a system designed to assure tiat claffied pemTnENd Property gathe and evalue the aocn subirrtted Baised on my hlquu of the persa or joeirons 1 40 -70= 5 2 Benjamin P. Youman who 8ma1ge te syste5rs 09/25/2012 bntonnation submitted Is. to the best at my Wwolidge and belfel, tree. accurate.

and -plete. lam SIGNAYURE O1RINCIPLE Plant Manager aware that tere are significant penas for submitting false iomuatlon, twe posstiy of EXECUTIVE OFFICER OR N EMA TV LM OR nEn Ie and IMonmen lor knowing violins. AUTHORIZED AGENT COD N MMDDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hers)1. Them was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow exdsted through this outfall 15 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvile, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 iL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUER 01) CS WWTP (FORMER 001C)External Outfall* NO DISCHARGE M " 61010 MONITORING PERIOD MMIDDIYYYY MM IDDYYYY FROMI 08/01/2012 iTo 08/31/2012 AI-rN: Zoe CoxIENV SPEC ____________________

___________________

A QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE APAAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE Zinc, total SAMPLE ........ ........ 500 (as Zn) MEASUREMENT 0109210 % PERM1IT 7 1 .2 " G.Effluent Gross REQUIREMENT

".. ... .30tA AVG DAILYMX ._ ..___Flow, in conduit or thru SAMPLE Fo.IcodiortuSAPE 0.0,18 0.025 3 ...........

0 01/01 CN treatment plant MEASUREMENT 0.018 02 0 01C 500501 0 -ERMAIT .- Req. M0.1 -.T."7 ?T ., " -" *?'0 ." --Elfluent Gross REQUIREMENT

-:30AAVG .. DALY MX ,.. ... ... ." ". -SAMPLE MEASUREMENT

• PIERMIT-

.,_.,,._. .,,"_',.._.

.,.REQUIREMENT_

_ __ _ _-_" SAMPLE MEASUREMENT

• PERMIT -77 77 777 .7ý. .-- .7`7 ---I- -7.T REQUIREMEI, T .... f. .-* , -., "..SAMPLE MEASUREMENT-PERMIT-.

77- ---s72-~~-~-

,9-REQUIREMENT

.. .-SAMPLE MEASUREMENT_______________________

PERMIT________________REQUIREMENT_____

________________________

SAMPLE MEASUREMENT

_ 7*PERMIT':

77__ _ _ _ _ _ _ _ REQUIREMENT"ER T ..'- .. : " ,." .. *-.,...- .-, .. .. ........ " ." ...._ _ .__ ___..___"1"__

__-__ _z _____1____:.,:

' " .. " __"_. ___... ...'1. .... ":. f.. '/ 7 T 7 .. ... ..NAMEjnTLE I cetilly under penalty of law thai toe document and at attachment were prepard under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direction o supaeWs in accordance with a system designed to assure tat quaifiod personnel N Ippety gather and evate the Information submitted Basd an y Inquiry of the person or persons 15 406-3700 Benjamin P. Youman who manage the system. or those persons directly, responsih for galierog the Information.

ths, 09/25/2012 ibormation suWnittod Is. to the beat of my knowledge and baitl. true, accJrate, and compiete.

Iam SIGNAj*E OF P",NCIPELE Plant Manager aware that there are ndicare penalties for submittng tabs Information.

bibding the possibl of EXECUTIVE OFFICER OR AREA TYPED ORt P101CFo annd imprsionment for knowing violations.

AUTHORIZED AGENT ]COD NUMBERI MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1112012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMrTTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvite, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC DMR Mailing 23P CODE: MAJOR (SUOR 01) CS 61010 IL0048313 PERMIT NUMBER DI01-0 DISCHARGE NUMBER MONITORING PERIOD I MMIDDIYYYY I I MMIDOIYYYYY RADWASTE TREATMENT (FORMER 0010)External Outfall I * *NO DISCHARGE ED ...FROMI 08101/2012 08&31/2012 Il ll lQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE QUATIYARMONCNTATONOF VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Solids, total suspended

............

...... 0.9 1.3 19 0 02130 CP MEASUREMENT 0053010 PERMIT I' .-T.viePerMort COMPO1 Effluent Gross REQUIREMENT " , " ' 300AAVG DAILY MX" .T c P M C..P. S Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT 5005010 .P.UW Req. Mon.' .... -7ReMo "7 " -.- ..Effluent Gross REQUIREMENT 30DA AVG DALY MX Daid "y "a CONTIN SAMPLE MEASUREMENT_____

PERMIT 7 --7. ". .7_______ ~REQUIREMENT

_ _ _ _SAMPLE MEASUREMENT PERMIT! 7 -. 7-7. ",.. ....._______________REQUIREMENT_____

_______________

MEASUREMENT_____

REQUIRMlENT

_ _ _ _ _ _ _ _SAMPLE MEASUREMENT Pl- -- '-"- -.' -:-.. -,..-*.. -.:: .: .*" .-..-..i__._-..__.__i._i REQUIREMEN." """ ____SAMPLE M EASU REM ENT -7 7 -_ _7 7 PERMIT REQUIREMENT I NAMERIN nLE Icertify under pealty of law that the douMe and al attahmants were prepard under my TELEPHONE DATE PFOOMPAL EXCTV OFI=ICER dretin -,tk supervision in accondance with a system designed to assure that waffed persannei propeuly gather and evaluta the Informatlon subinett Based m my Inquiry of the persn or pesmons J\ 7d 815 406-3700 Benjamin P. Youman who manage the systen or those persons directly responsble for the Infomaitlon.

the .1..- 09125/2012 informatio submitted Is. to the best d6 my kovtedge and beflef. true. accumrae.

and ccmpiete.

I am SIGNATiE OF _ _ __ChPLE Plant Manager aware that there are signcant penalties Ifr submitivg lalse informion.

ncuding the possbfty at EXECUTIVE OFFICER OR AREA porrm lm mid it men for knowing vidanno. AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hers)1. Flow existed through this outfall 9 of 31 days durng the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116912 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEIAODRESS NAME Exelon Generation Co., LLC ADDRESS 4300 winfietd Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER I MONITORING PERIOD I MMIDDIYYYY I MM/DDIYYYY STORMWATER (FORMER 001E)External Outfall I I I NO DISCHARGE -J FROMI 08/01/2012 I oI 08/31=2012 I I I ATTN: Zoo Cox/ENV SPECFREUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids. total suspended SAMPLE ....MEASUREMENT 5 0053010 PERMIT 7. .. 30 -'We"" GRAS Effluent Gross RE0UIRBAIT

___...:__

___AAV___- -M-Solids, total suspended SAME 7.9 8.0 19 0 01/07 GR MEASUREMENT_____-

0053080 3 0 Other Treatment, Process .. ..,..,. A ., ,ee "' , ...Complete _ -,__. .... ....__-__. __.._"_"_.

.Chromium, hexavalent SAMPLE 500 (as Cr) MEASUREMENT 500 0103210 7p~j~ W w 77 D:ny 2:7, Effluent Gross REQUIREMENT " "_"__'_.--:

.30ODAAVG DAILY MX GRAB Chromium, total SAMPLE ...500 (as Cr) MEASUREMENT 500 01034 1 0 7- PERMlr ,,, :1 -7 2 ". G Effluent Gross REQUIREMENT

.._*.._". O3DA AVG DAILY MX -Copper, total SAMPLE ...0...... ...(as Cu) MEASUREMENT 50-0104210 PERMIT ,..,, ; "... ' .5 -.. '. G.AB Effluent Gross REQUIRBIENT

• _ " _,,__....

"30DAAVG bAiLY MX -_" Iron, total SAMPLE ...... ..... So5 (as Fe) MEASUREMENT 0104510 PERMIT ..... .... -" -cc- ---- "" Effluent Gross REQUIREMENT

"__ _ ...__ DAILY MX .GRAS Lead, total SAMPLE o..... ....... 500 (as Pb) MEASUREMENT-010511 0 PERMIT -..,... -,... ..., .2 .4 *Effluent Gross REOU .* EMENT. 300A AVG DAILY MX GRAS KAM E/nnE I celt./under penalty ol law awi this domimemt and an attaorhmens were prepared under my TELEPHONE DATE PRNCIPAL EXI.CUTIVE OFFICER oreton or supenisiTLn accordance wEh a sDTtem designed to assure ow TEaPiOd pNE DAT propety gather and evatute the Infmmatin submied. Based on my bIqutry of the pemmr or persons 5 43 Benjamin P. Yournan who manage the system, or 0Ue persons drecty responsUe for gatetrng me the 4_0 09/25/12 Wonnatlon submfted Is. to the best of my knowledge and beliet, ue. eccurate, and comrplete.

Iam SIGNAinEOFII PLE Plant Manager aware that them arm sigcant pentites for submftnig fals inlomratton.

kitng the posay ol EXECUTIVE OFFICER OR AREA NUMBER MM/DD/YYYY owR Poi is and ouisonment for niowkii viltions.

AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow existed through this outag I of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11112012 PAGE 11 0 0 49 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEJADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER I MONITORING PERIOD UM/DOVYVYY MMIDMNYYYY STORMWATER (FORMER 001E)External Outfall** NO DISCHARGE F- ...FROMI -08/01/2012 I TOI 08/3112012 I FREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel. total SAMPLE ...... 500 (as Ni) MEASUREMENT 502 0106710 ..-:AVl RM .- ." ." .+" ."- -' " "a "" Effluent Gross REQUIREMENT 5-" , YMX*Zinc, total SAMPLE 50..0o (as Zn) MEASUREMENT

• ru" rr .*.AAV -. .A..,,1 01092 1 0 *PERM IT ' 2 .m.& *a .RA1 ..... ' :. .. -. ...Effluent Gross REQUIRE1M"NT 6 30DA AVG ""LYMX .L.Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT 5005010 PERMIT Req. Mon. Relq. Mft.-Effluent Gross REQUIREMENT 30DA AVG -Rg-.DAILyM.MX" Per Mnt CT .SAMPLE MEASUREMENT PERMIT ---_______________REQUIREMENT'__________

__________

SAMPLE MEASUREMENT-PERMIT_______________REQUIREMENT,_____

________ ____SAMPLE MEASUREMENT

__________

________ ___REQUIREMENT

__________

________ __________

SAMPLE MEASUREMENT PER~~rr : -.-. .................

"-.;,".+" .. ......- ....'..-- .............................

'.1 " -.i.' -" .,:+.;.- REOItRqEMBII

"___________

-. ____ ___"__ __REASUIREMENT NAMEnTTLE I cattily under penalty of law i0at t~s document and al attadcments were prepared under my TELEPHONE DATE PFNC4PAL EXECUTiVE OFRCER directin or supenidslon In accordance with a system desined to -ssure toa qualified personnel properly gathe and evahtVithe Informain smtllted.

Based on my InCqury of the personr pesona Pa Benjamin P. Youman whto manage the system or thse persons directly responsible lot gatheuing the inlion.iF, 815 406-3700 09/25/2012 minoration submitted is. to fte best of my iknoeedge and balef, tuse. atmuret and complee lamn Im NATU OF P Plant Manager aware that them amr sniFfcant pen for submnt false Infonrttion, thnft the possblt of EXECUTIVE OFFICER OR ZAR NUMBER I ly PsoR pe d e and b tsnent for iprowng vicationm AUTHORIZED AGENT CODE _MM/DOYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Service Water or Closed Cooling System Drain Water was discharged this month.2. Fire Protection drain water was discharged this month.3. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Cleaning wastewaiter was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE?

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS' 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS COOLING SYSTEM SLOWDOWN External Outfall 61010 MONITORING PERIOD MMIDD/YYYY I MUMID1Y YYY FROM I 08/01/2012 ITo I 08/31/2012 l* NODISCHARGE

...! I ATTN: Zoo Cox1ENV SPEC____ __________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SA.MPL VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS ETYPE Temperature, water deg. SAMPLE ...... .........

0 01/01 CN Fahrenheit MEASUREMENT

.00011 10 ... PEM....7'~

~Effluent Gross REQUIREME)N MO ..pH SAMPLE 7.81 8.31 12 0 01/07 OR MEASUREMENT Effluent Gross REQUIREMENT..

N..U- ....... .-L I __.MNIU _ : " -." MAXIMUM'.

..-S total suspended SAMPLE ........ 12.0 12.0 19 0 01/30 OR MEASUREMENT

_ _ _ _ _ _ _ _ _ __ _005301 0 .M -" ' '. ,;, -. Req,Moret-:

' .Mon .....' * ..Effluent GrossR -I, M E ... , I "" :' '6 "". " :DAAVG/. .. DALY.IMX -.. -" B Oil & Grease SASRMPLENT

<11.4 <1.4 19 0 01/07 GR MEASUREMENT

_____0055610 PERMIT 7. 2 'D -" " ...15 --20G R.: Effluent Gross REQUIREME9T

.". '30DAAVG DAILY .. -W.ey.. GRAB Chromium, total (as Cr) SAMPLE .............." ... ... ... <cO.0021 19 0 01/07 OR MEASUREMENT 010341.0..

.......... " oL -: .Effluent Gross REQUIREMENT DAILY_" .., .....-,. ... ....Copper, total (as Cu) SAMPLE ...... 0.015 19 0 01/07 OR MEASUREMENT 0104210 -PERMOT!- 777 .017 Effluent Gross REQUIFIEMENT

... -..DA5LY 0M07 '.. .-Zinc, total (asZn) SAMPLE .<0.003 0.006 19 0 01/07 GR MEASUREMENT 1.01092 10 -.PEROIT -.X -.1 -?:;-; 7Y Effluent Gross RiMUIREMEkT

--- 300A AVG DALY MX..-NAcE/tITLE Icaly unWer penaflyal law wat ts doument and all atachments were prepared wnder my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER dbectia or supervision I acoidanre with a system designed to assure Mat qiaped p rope rty aU wrand e au e f r ame atnmo su bm itt , eaed.S on my mquiy a M pe rm o rpe 815 406-3700 Benjamin P. Youman who manage the ssM7M o 00se persom diecty IsonA for pathe the ,omatim. te 09/25/2012 kdarmntion suttmided Is. to the REst d my Q and Iel, true. II, and , e.laIa OI= CiPLE Plant Manager aware Mal Nude are signiicant penalties tor suvmft lalse mtiarnon.

bIdnurd the possaty dl EXECUTIVE OFFICER OR N EY 1W0on Ra f and EWUsiomem W owf vattis. AUTHORIZED AGENT COaE NUMBER MM/DDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmenta helr)1. Monitoring data for outfall 001-0 is Included on attachment.

EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11u2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER DMR Mailing ZIP CODE: 61010 MAJOR (SUER 01) CS COOLING SYSTEM BLOWDOWN External Outfall* *INODISCHARGE EJ i MONITORING PERIODI I .MMIDDJyYYYY I I MMIDD/YYYY I---------

4 FROM t__ -1 08/01/2012 l1 1Uýýglcvic QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OFANLYE_________________

ANALYSIS TP SAMPLE ........ .n.t ....... .519 0 0/7G Oxidants, total residual MEASUREMENT 0.0 19 0 01107 R 3404410 "PEuMr. , ..r.. GRAS Effluent Gross REQUIREMENT "I MX "_T- y Priority pollutants total effluent SAMPLE 500 MEASUREMENT

__________

__________

________5000810 PERMIT-mm Fq.Mn.... .. " * *. DAILYM X 'Effluent Gross REQUIRSEIM ENT DALY MX- ..W__... .DAILY.... .A Flow. in conduit or thru SAMPLE ....treatment plant MEASUREMENT 5005010 PRMIT .Req. Mwn Req. Moný. 'i~ S 8~CONTIN Effluent Gross REQUIREMENT 30ODAAVG' DALY MX. jly:__ _. __: _.__ ,_"_...._

.__",,, -. .Chlorine, total residual .....S .ME .. 500 MEASUREMENT 500601 0 PERMIT II- ~ ~ ~. 0 Effluent Gross REQUIREMENT

_-_*_": ._., .." .- ,. ,AILY( Weekl. GRAS Hydrazine SAMPLE ...... ... .-..."500 MEASUREMENT 81313 10 PERMI.:0 2-...*- .Ol07 clawil Ihe GRAB Effluent Gross REQUIREMEIT " _.. ... __ .__, _ ._ -SODA AVG -DAILY MX .-.SAMPLE MEASUREMENT PERMIT" REQUIREMENrT

.._... .__"_/______

SAMPLE MEASUREMENT S*li T ..* : .: .- .- , ..: ..- .-... .-, .... -.... ..... ...-REQUIREMENT

-.NAUEnrrrLE cernny unlder Penl aft Il truef MM;;; and JTEaLEP ONE DATEM PRINCIPAL EXECUTIVE OFFCER directlmn or supeviaslm bI accodance with a system desgned to assure that Wafi Persnel TELEPHONE DATE pperty gaMtariand evakfte I memation Based on my tlquiy d Me pesant or 'Il 81 406-3700 09/25/2012 Benjamin P. Youman who manage the system, o Mome persons dsvecttm respanslet for gathering the Infonatim.

Me SIGNA IRE OF iINClPLE 0_r_5/2012 Plant Manager kommaa submitted Is. to Mte best ai my knowledge and belIef. that. acmirate, and eomplete.

I am UTOIVED AGEN CM awarehgo tere a re signifcant penaltes fo r su bmittig fa bse info rnatim. In kd ing the ssitf ofX C T V F I ER O R A N M E M M /DO/YYYY fnOn pME fe and hToelsbrntment for knowbnW violations.

AUTHORIZED AGENTE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 111/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Wintield Road WarrenviUe, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road OMR Malting ZIP CODE*MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD MMnDDvYYYY I I MMIDDIYYYY STORMWATER RUNOFF BASIN Extemal Outfall* -NO DISCHARGE 1 ...I I I I FROM I 08/01/2012 I TOI 08/31/2012 I Byron, IL 61010 ATTN: Zoo CoxJENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER

_____ON.SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALO TYPE SAMPLE t*.nneee e oeo Solids, Total Suspended MEASUREMENT______________

0031 rITll~-

-.., ... .,,.,30OAAVG1 "n ,...n."We

'"GA'Eiffuent Gross EURIT ....SDAV DAYM'Wel.

GA SAMPLE ..... .............

Solids. Total Suspended MEASUREMENT 0053080 -'.. ......./. --. V R. ..; .... I GRAD Offluenth Troa-ss REORUEET-

-:'!.i:, !'. 300DA AVG -DAILYMX" ng/L *, Weely.,$ A Com olete _.. _.- ___..- _- *__ __ _ _ ,, .-' .* .-. -- -*... "-. ...Chromium, hexavalant SAMPLE ........ .....(as Cr) MEASUREMENT 01032 10 *-. PERMIT"+"-":'

,,. ..-, :- te.,.," -'+" " : -. " .0o1 ~6 .i " ': " .+"; -:+ ..".... ... .. hV LW" , :; I .* .Etuert Groatent RErUceMss

______ 3 AVG DILM -3GA Chromium, total SAMPLE (as Cr) MEASUREMENT 01310PAERMIT-

.01' al -RB'1EIff t Gs- " O "DA AG" DAILY MX" .. " Choim toa SAMPLE I Copper, total SAMPLE ... .., ... ...(as Cu) MEASUREMENT 01034210 , 7...... .. 7 .7 .... -t -3 Effluent Gross

.SDA AVG ,DAILYMX ..GRA.Iron, total SAMPLE n.... ......(as Fe) MEASUREMENT 0104510 " PERM ...- j.77 7 7 V "

• 71". .Emuent Gross RE.UI El ... -DAILYMX mgIL Daiy GRAW Lead, total SAMPLE ..........(as Pb) MEASUREMENT 01051410 PERMIT" -... " ". "GR.S .63 298.Effluent Gross -REQUIREMENT , .,. ... ..SODAAVG DAILYMX. D.. .... GR ..NAMITInTLE Icerwy unmut ienasy tw mat ets doonent and sit etadeirent~s were prupaed under myTEPONDA--

PRINCIPAL EXECUTiVE OFFICER dfrctia ot supensmon In accordance wttt a este designed to msure.-a qiagte TELEPnNEeDAT whoen am anag te sstm o toe pe iscom dresuy m.pBasbed fon gatqwing the peomatmt Vt.nm 154630 Benjamin P, Youman wh anagdessn ovaji de Inom istio msonse my QaU'yn de PcmtSon W 815, 406-3700PL 092501____ fits a~nd mieomn o mwzgvoain.nomtalio subinlied ts. to mhe herl si my fooleg and bethe, true. somurat and om~plete.

Irant IN R NIL _ _ _ _ _ _ _ _ _ _ _ _ _ _Plant Manager sware tttt there ame signifian pensates hrosubitting be Iroisi btdudng mhe poessey c EXECUTiVE OFFICER OR AR UMEEMAWYY"nmm ____ ___ ___ __PERMIT___________

AUTHORIZED AGENT COD7 NUMBER M7-DD/_ __Y COMMENTS AND EXPLANAtION OF ANY VIOLATIONS (Reference all attachments he)re 1. No Tutbine Bwidtng FIre and Oil Sump or Genetic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No re Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPAForm 3320-1 (Rev 01/06) Previous editions may be used. 1/r/2012 PAGE 1 EPAalnsb~c s otebe fIn nweg mble.tuamae adcnf .1a INTR tRNIL 0 PERMrITEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvitle.

1 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 610107nar twIF=NV SPI=C O NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)DMR Mailing 23P CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDJYYYY I MMID/YYYY STORMWATER RUNOFF BASIN External Outfall... NO DISCHARGE jjJ I .... .. .I I I FROM I 0810112012 ITO 08131/2012 I I QUANITTY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMErIER OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Nickel, total SAMPLE ..........

..(as Ni) MEASUREMENT 0106710 .GRPERMBIT'

---'ee em.' .011+ " " .' '+* .-- ..- 30DAr AVG DAILYMX,.Effluent Gross REQUIREMENT

__ .-"____ -_,_- _AMX *GRAS Zinc, total SAMPLE .. ...(as Zn) MEASUREMENT 0109210 P1011117 .,, ---, .... 047 .26 Effluent Gross REQUIRENT ADAIY"MX t' Dally Oil and Grease SAMPLE....

MEASUREMENT_

03582 1 0 PERM IT 7 7"7"-"-7e'! " .15 " * " Effluent Gross REQUIREMENT

...._.__*.__300AAVO DALY MX .I.I.._c ..,, -Flow, In conduit or thru SAMPLE .... ... ......treatment plant MEASUREMENT 5005010 PERUT -RKq'Mon. -- Req. Mon. ..... .hn, Effluent Gross 3DREQUIR "V" 300A AVG DAILY K .. .. Discha. ging-SAMPLE MEASUREMENT REQUIREMENT

"~~~~~~~~~~..

.. .. ....--." .. ....-'-.,-.......

• , -... ...,' .....______________REQUIREMENT

,_________

---SAMPLE MEASUREMENT PERMIT REQUIREMENT

'_" _,__SAMPLE MEASUREMENT

________________REQUIREMEN1

___________

________ ______ ___NAME/1T1.E I certily under penalty of law that this docurnen and all atachmens were prepared undr my TELEPHONE DATE PRIMCPAL EXECUTIVE OFFICER O superisio In accordance wbi a system designed to assure ta quaeued pesonnel B .roperty ga-the and evate fte Informatio submitted.

Based an my mlquwy o the person or persons 815 406-3700 Benjamin P. Youman who manage the system, of tose peemons directly responsible for gathering the mforimatin, the 0942512012 mtfor.ation suftned Is, to the best of my linoledge and belJ, bee accurate.

and conplvete, am SIGNAa EOFP CIPLE__Plant Manager aware a Owere am saqicant peraiafttsor aisuMinaO raise Imtonna.on Inctuding the Possibityd EXECUTIVE OFFICER OR UBM.A TVMm OR PRO'ED fine and irnipdionmenl for woxmg viclatmons.

AUTHORIZED AGENT OD NUMBER MM/DDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 2 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 August 2012 Page 1 of 3 MONITORING DATA: CWBD CWBD Flow Rock River DATE Temperature d Flow de F mg cf 08/01/2012 100.0 19.82 1,900 08/02/2012 100.0 21.62 1,890 08/03/2012 101.0 20.67 1,840 08/04/2012 101.0 28.92 1,890 08/05/2012 100.0 21.11 1,890 08/06/2012 98.3 13.43 1,820 08/07/2012 100.0 22.51 1,840 08/08/2012 100.0 9.30 1,830 08/09/2012 98.5 17.04 1,860 08/10/2012 95.6 16.07 1,900 08/11/2012 97.3 17.09 1,820 08/12/2012 97.3 15.25 1,840 08/13/2012 95.5 14.28 1,860 08/14/2012 96.3 22.12 1,830 08/15/2012 100.0 19.58 1,850 08/16/2012 100.0 24.91 1,890 08/17/2012 98.9 18.27 1,910 08/18/2012 98.1 27.19 ,810 08/19/2012 95.2 22.86 1,830 08/20/2012 94.4 16.50 1,820 08/21/2012 95.5 19.79 1,790 08/22/2012 97.1 16.71 1,800 08/23/2012 97.1 17.08 1,760 08/24/2012 96.6 17.76 1,760 08/25/2012 99.8 15.95 1,680 08/26/2012 97.8 18.62 1,660 08/27/2012 97.1 13.46 1,690 08/28/2012 99.5 22.30 1,590 08/29/2012 98.5 17.98 1,600 08/30/2012 101.0 17.03 1,630 08/31/2012 102.0 18.14 1,550 K:\BYR_CH-BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\August\August 2012 ATTACHOI.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 August 2012 Page 2 of 3 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of August 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 37.0 mg/L on 08/06/2012.

The CWBD TSS value was 12.0 mg/L on 08/06/2012.

5. Rock River flow was <2400 cfs in August 2012 therefore daily temperature calculations were required during this time period. (Special Condition 12).Per Special Condition 12, in the event the Rock River flow is <2,400 cfs, daily calculations will be undertaken to demonstrate compliance with the water quality standard.

The calculations are based on hourly measurements, averaged over a 24-hour calendar day for Rock River flow, main Rock River temperature, CW Blowdown flow, and CW Blowdown temperature values. Results of the calculations shall be reported in the DMR on a monthly basis. Calculation results are in the table on the following page.6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in August 2012. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\August\August 2012 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 August 2012 Page 3 of 3 Date Average Average Average Average Calculated Water Quality Rock CW M/U CW CW Temperature Standard River Temperature Blowdown Blowdown at edge of Temperature Flow (F) Flow Temperature mixing zone (F)I_(cfs) (gpm) (F) (F)8/01/12 1910 78 15492 97 79.0 90 8/02/12 1892 79 15386 99 80.0 90 8/03/12 1848 80 15255 100 80.4 90 8/04/12 1867 80 15531 100 81.2 90 8/05/12 1939 79 14197 97 79.3 90 8/06/12 1820 77 10402 96 77.4 90 8/07/12 1840 77 11936 98 77.5 90 8/08/12 1818 76 12105 97 76.9 90 8/09/12 1863 73 12130 95 73.9 90 8/10/12 1889 71 12022 92 71.7 90 8/11/12 1828 71 7827 91 71.4 90 8/12/12 1845 70 12257 93 70.8 90 8/13/12 1850 69 14858 94 70.3 90 8/14/12 1828 69 14927 97 70.6 90 8/15/12 1849 73 14998 99 73.7 90 8/16/12 1881 73 15125 98 73.6 90 8/17/12 1914 69 15320 93 70.2 90 8/18/12 1800 71 15278 94 71.8 90 8/19/12 1831 70 15283 94 70.9 90 8/20/12 1821 69 13557 94 70.3 90 8/21/12 1790 71 14433 93 71.7 90 8/22/12 1799 71 12377 94 71.6 90 8/23/12 1768 72 12491 96 73.1 90 8/24/12 1765 74 8394 97 74.5 90 8/25/12 1691 74 12515 98 75.2 90 8/26/12 1654 74 12906 97 74.9 90 8/27/12 1695 73 13512 97 74.1 90 8/28/12 1590 74 14901 97 75.5 90 8/29/12 1603 75 12747 96 75.5 90 8/30/12 1628 75 12720 97 75.9 90 8/31/12 1555 75 11960 100 76.4 90 K:\BYRCI-I\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\August\August 2012 ATTACHO0.doc Exelon.Exelon Generation Company, LLC www.exeloncorp.com NEuxeaT Byron Station 44,o North German Church Road.Byron, IL 61010-9794 October 16, 2012 LTR: BYRON 2012-0112 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of September 1, 2012 through September 30, 2012.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035..Respectfully, Bena ýYoumae Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments bcc: J. Gould -Environmental

-Cantera (electronic)

Z. Cox -Chemistry

-Byron 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road IL0048313 PERMIT NUMBER I DMR Mailing ZIP CODE: MAJOR (SUDR 01) CS 61010 I A01-0 t .......[ DISCHARGE NUMBER DEMINERALIZER REGENERATE WASTE (001A)External Outfall I MONITORING PERIOD I MMID01YYVY I TO[MMIOD/YYYY I FROMI 09/01/2012 09/30/2012 I* ** NO DISCHARGE M ...l g Byron, IL 61010 ATTN: Zoo CoxIENV SPEC _____________________

______________________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAME'TEFR OF ,,, VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids. Total Suspended

............

CO.71 40.71 19 0 01130 08 Solds ToalSusened MEASUREMENT 0053010 EMT --Effluent Gross PO. MP .,-..- _-.... .COW-a Chromium.

hexavalent SAMPLE ...... ....(as Cr) MEASUREMENT1 0103210 ... .2 Effluent Grosse' ,.: .. 4 p A A -"ALY Mx-" " -Chromium, total SAMPLE ........ SI (as Cr) MEASUREMENT,-

-0103410 .- MIT ~ ,... .-.. .G Effluent Gross 2.!- 1 .., -., , ..-Copper, total SAMPLE ....... ..(as Cu) MEASUREMENT 0 10 42 1 0 Soo.. .. ....:, : .-" -' , ..-. .y G.A_Effluent Gross r: ...... -.- W.D- I .." ...... .-,.. -Iron, total SAMPLE .........(as Fe) MEASUREMENT 0104510 SMT- ,, ~ .~ ' ml___ _ _ _ _ _ _ _ _ _ _ _ IX

• R Effluent Gross .: .... ;" : ' .., ' ; " ." '. " .-.Lead, Total SAMPLE .., 5 Effluet) MrssEASUREMENT~~-'

~a~ QDAVG~~Eflu ntGos s .1 1 --.": .;./ --. ;- .: ..Nickel. total SAMPLE ....... .(as N i) M EASU R EM EN T ...... ...... _ _ _ _ _ _ _ _.._01067.10 500 , .- -_ ., ..<:, .2 Effluent Gross *UA-UIR..IBN

' .S ..._ -:.O;. , ,. , .X .: _ .._ .. ...2.--NAL EX TTI I. E I ceairy under penally al lw thWat fts documnTu and all auduna rAlm wer pWepared under ny TELEPHONE DA TE PfiINCIPAL IXECUIlVE OFFICER decton or Bupenivwm i aI n darnc wih a systen designed to assure tha qualfied personnel TELEHON DATE property gather and evalute the ettarrnamat submtimed Based On my hoqiity d the person or pawsna 1 6701~~1 Benjamin P. Youman who manae the syateM or =me persons directly resplble f1w gaherng the Infofmnatft the6101 Pna onnatton W uOrti n ted is. to the best of my W ledg and be e, Ine , eca rrea .and con e .Iaia SemN RE 0 INCtPLE Plant Manager aware at there aM sedmiPeant ies for sulnftaveingoIdeaisn, nalia 9 thngposl EXECUTVE OFFICER OR NURE ER MMIDDIY TVPED OR Pmur It'- end unprdeiounent fmr knowing viadow XCTVEOFCR R AE iwaoon pur ean ctssm m fc voa~ AUTHO RIZED AG ENT CODE NUM BER _ _ _ _ _ D_ _ /_ _ _ _ _ _COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmente here) ...1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed 30 ot 30 days duing this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11/62012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exalon Generation Go., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER A01-O DISCHARGE NUMBER MONITORING PERIOD MMDDYYYY I MMIDDTYYYY DEMINERALIZER REGENERATE WASTE (001A)External Outtail* NO DISCHARGE FROM i 09/01/2012 1 TOE 000/2012 Il i i I ATTN: Zoe Cox/ENV SPEC ____________________________________

_____QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF AML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE ZInc, Total SAMPLE ......is.

• ee

• otQ = m500 (as Zn) MEASUREMENT

__0109210 2." ~ _ .-'. .oi s.o .- .*

• 2ri. .-.ail: G -Elffluent Gross ." BAB-4~?-.

~____Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT 0.057 0.243 3 0 01/01 ES 5=00510 9WQ MWLI RMVW*Effluent Gross -- -.--NTIN MEASUREMENT

__________

• . ..--- .* -____lO__ _-_ -, RA-UI-. R"M.---- ..... ._ C SAMPLE MEASUREMENT

.*... ., ___.,_-._._.._

.,- -. * ..- .*. .-'-SAMPLE MEASUREMENT__

_ _ _ _.,_" -. '<.. .. ; ' ..... _ _ _ ". _ _ _SAMPLE MEASUREMENT SAMPLE MEASUREMENT.WWW 7. t -NAM, lurpE PAINCIPA EXECI~fVE OF &G- Or at osupervisio In accodance widi a system designed to a=sure diat qtiatle personnel

_ _ _ ____________

NAME~~fl1L PM I cetd h Uif plaftY Ci aw dae Me docmeihnt subid tted Bsd anmy vptS a5Illd ft~d perso TELEHONEDAT BejmnP omn who manage die system. orthos person diudly resporisidl totgatheringdie informalke~t, di a7(informataio submitted IS, to Ite best of my knowledge and balet. true. accurate.

and complate.

I SIGNATWRE OF P~jWCIPLE

____ W ____0__1__2012

_Plant Manager aware diet diers are sign~llcaml penalties tor aubnudg 1MM kinlommtlo.

hi~dkig die possaif of EXECUTIVE OFFICER ORNMERMDDYY pWED OR__________________________________________lations AUTHORIZED AGENT CO4 NUMBER ______________

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)CO _1. Flows for September 2012 are estimated based on July 2012 values due to totalizers being Out of Service. The totalizers are an obsolete model and work orders are in place to find replacement totalizers and get them installed In thes system.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/212 PAGE 21 0ESRMN PERMITTEE NAMEJADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 NATIONAL P&LLUTANT

1. ARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)I DMR Mailing ZIP CODE: MAJOR (SUDR 01) CS 61010 I I.0046313 I I B01-0-4 PERMIT NUMBER I I DISCHARGE NUMBER 1 MONITORING PERIOD MMJDDIYYYY i MM1DWfYYYY STP PLANT EFFLUENT (FORMER 0015)Extemal Outfall* NO DISCHARGE FROM I 09/01/2012 I TOI 09/30/2012 I! lM41IIfl. £. 't.AJflO*Y Or--1 _,, _FRE______SAMPL QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAME'TER OF YP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE BOD, S-Day SAMPLE 21 .62 BO 5- 2C14 3.76 26 .... 29.0 50.0 19 0 02/30 24 E~ffluent Gross _011-~ ____ _____ ,ALW wPMr~MEASUREMENT

_yat 0040010 .Q.. "-a.. t..Effluent Gross TIM ~~ ~ ~ -SJ ~GA-m illn e ',. ýý i pa. --.. ,.1 ,,1111 I- .o .I- .-- ....."o--~Soital sSUdMPLE 121 2.22 26 15.7 29.5 19 0 02130 24 Solds toalsusened MEASUREMENdT 0053010 5.)u 1015' 30 60._~~ ~ ~ ., -,,.. .-. w_ý " IaIYX 'A*m .I! .......w.Effluent Gross PY&L ~I4N Flow, in conduit or thru SAMPLE treatment plant MEASUREMENT 0.008 0.014 3 0 01/01 CN 5005010 ~. e.Mn eJ4n'-v-'pM OJI Effluent Gross ,.emu W 9&2mA ' -_____ -SAMPLE MEASUREMENT aco .n.*. ..REQUIREMENT.,, SAMPLE MEASUREMENT_____Iil r,___. .._ _ _ .t. ; 1" , .: ... .... .;. .... ..."__.. .._ _ " " SAMPLE MEASUREMENT NAME/rrTLE comfy under pealty of law owUist1t document and anf attachments were prepared wnder my PMMciPAa.m or -,

.... in ....anc wi- , a syster- das..d .s .r. M,.........

TELEPHONE DATE whOSI mOandg the kf fyte. 9orun.emnal dibrrtetl BO r anrnyl lo" gted go therslmaton thep Benjamin P. Youman propeif ngatheresyseemkor thew Persons iatam rsubituted.

for gatheingub flte peaT=o esn ________ 815 140&3700 10/l1612012 W'Om'Vallm eubnto IS. to the bea of MY kz(IONISC and bmele, tre actae and cornpals.

I am SIGNA SRE OF IRINCIPLE

-Plant Manager aware that atere ame elgnant penaltes tar subiitltki false bInornnedel.

Incben die possbdty d EXECUTIVE OFFICER OR EAl UMERMID1YY iwwn OR IRMUTan r- and brfbufn fo bmwb v~a AUJTHORIZED AGENT IcoDEj U1E MIDY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attarhment heme)1. FRow existed through fthi outfall 28 of 30 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116120112 PG NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITI"EE NAMEJADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvlle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road.... I I DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 I PERMITNUMBE I I-C01o0........ I I PERMIT NUMBER I I DISCHARGE NUMBER 1 MONITORING PERIOD MMIDDIYYYY I MNIJDDrYYYY WWTP (FORMER 001C)External Ouffall.. NO DISCHARGE EJ FROMI 09101/2012 I Tot 0930=12 I II Il i Byron. IL 61010 ATT'N: Zoe Cox/ENV SPEC ________________________________________

_____QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY IPLE PARAMETER OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE SAMPLE ....... ..... 2.4 2.9 19 0 02.30 24 SolidS, total suspended MEASUREMENT 00M3010 v.. PERM , ....1_ ., .._. .' ..,.: w._, Effluent Gross : .... ... , _, _.".... .,-Chromium.

hexavalent SAMPLE .........(as Cr) MEASUREMENT 0103210 -iI..e I .," ". .: .1 " 12 Effluent Gross _,__T .. ._ "__._ _ _..._.. .... DAILY MX -9111 .GRA Chromium, total SAMPLE ...... 500 (as Cr) MEASUREMENT 0103410 .EI.h...1..

2...Effluent Gross " ____-__:.

.. __._'" "0. " -A Copper. total SAMPLE ..............

..(as Cu) MEASUREMENT 0104210 Fir R3IMTvi-*'.

Eff luent Gross BEQUIRWENT 0 fl Iron, total SAMPLE ....0......0 (as Fe) MEASUREMENT 0104510 P.gRTW ,,m-' .Effluent Gross ____........

DAILY m-Lead, total SAMPLE ....500 (as Pb) MEASUREMENT 0105110 RMT -., 2 Effluent Gross REURM~ ____ ' ~ ~ AAV.G Q'AIIY.MX

-. RA Nickel, total SAMPLE ........ S (as Ni) MEASUREMENT 0106710) PAMIT ..* ', 2 .p ~ ___Effluent Gross go%. .I "-. ____ ,_ ---DA AVG O.iV , ..... _.. _-NAMMEfIII I tans under penagy oflaw that this and aD aftadunent were prepared undeer ff TELEPHONE DATE PRIM.AL E OICER wemor auennsion in aOFRanEe wR a spter desqned to assure TE quaEied PHONEAT pmpefty garer and evahita Me ,umtied. Based on my muwr a me pemro or pemrsos 815 406-3700 Benjamin P. Youman who nanage mte SySM6 OF me" peOsM imty respasAe for 9afuig the imomaun. me 4 406-3700 10/162012 inonn ubim te is. to fe beat l my knowedge and true. acuuae. and cdnplete.

Iam SjGN4VURE OF PI__INCIPLE Plant Manager awa"M trmUe we sindifcant ,enwoes for wutAnlifng false Wmain.m bxidng fte posaslif of EXECUTIVE OFFICER OR AREA wela l xtta _ _e __and ________n_

for _mo _ _ _ _ vi__al_ _ __. AUTHORIZED AGENT 1coD NUMBER MMDD__ _ _ _ _COMMENTS AND EXPLANATION OF ANY VIOLAT1ONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outall 19 of 30 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1 0 0 0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMI1TrEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvifle.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 AT-N: Zoe Cox/ENV SPEC OUR Mailing ZIP CODE.MAJOR (SUBR o) CS 61010 IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDO/YYYY

_ I MMJDOIYYYY WWTP (FORMER 001C)External Outfall I* NODISCHARGE-l FROM[09101/2012 I Tol 09/30r2012 Il Jl I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER

-.OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Zinc, total SAMPLE ..... ..S, (as Zn) MEASUREMENT 010921 0 ..........

.". .A...__- GRA-Effuent Gross rE~I~IU 6y:. RaAy iLD Flow. in conduit or Uiru SAMPLE treatnment plant MEASUREMENT 0.024 0048 3.0 01101 CN 5005 10 w'"FR-.. Mon. R- MMn. .i * ," Effluent Gross l -..-- ", SAMPLE MEASUREMENT

-.- -: : .. ... ...' :: : ..,,*. .. .....SAMPLE MEASUREMENT

________________

EQUIREMEMT.

.' , SAMPLE MEASUREMENT_______________________________________, .PaRM.T .7 .. ,-.-

-., I -' -, .....SAMPLE MEASUREMENT SAMPLE MEASUREMENT UREMENTI criyudr eal flw d ot ocm nt n talntwerepeprd nerm TELEPHONE DATE PRINCIPAL EXECUIWE OFFICER urection ar superision In accorance with a system designed to assure thai quaffied personnel prepetgater and evalute the Inforaton asad on my Inquiry ot the person or persons 815 406-3700 Benjamin P. Youman omanage te system. or thse persons diectly responsIft for geaming de Irloimatim te 10/16/2012 nformatlon submited i. to th be my k e a b, t, accrat. a c .I am -SIGUATUREfOF PRINCIPLE MOM and ipithiwefornt IknO io .AUTHORIZED AGENT c2o NUMBER M__ OD__ _ _ _COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference ali atlachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 IL0048313 PERMIT NUMBER I DMR Mating ZIP CODE: MAJOR (SUBR 01) CS 61010 D01-0 DISCHARGE NUMBER]MONITORING PERIOD.MODDIVYI I MMIDO/YYv RADWASTE TREATMENT (FORMER 0010)External Outfall NO DISCiARGE

-- "*FROMI 09101/2012 09/30=2012 IlATTN: Zoe Cox/ENV SPEC______________

__________

__________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER____" _OF__ AMPLIE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX A S TYPE>< ANALYSIS Solids, total suspended

"" 1.2 1.4 19 0 02030 CP MEASUREMENT 30501 .1 i-3 Eflun Grs z #-.6 yW Flow, in conduit or thru SAMPLE ... ..0.. 30....teallment plant MEASUREMENT 00600530 011C 5005010 V.w*. 3fy CN 1 g Effluent Gross "Ohl A.m. -ONTIN Raw %,( -:...SAMPLE MEASUREMENT SAMPLE MEASUREMENT_____

&AMPLE MEASUREMENT______________________

______MEAUREMENT-

'InTE I car*y under Penalty af law that Oft document and all attadrnenta were prepared unlder my TLPOEDT PrPNopel athe and evalute fth adnloraton submitted.

Based on mInquk hM the person at Persons 81 406-3700 Benjamnw P. Vouman wit manage the WaUnt. of those Persona dirfdi resp fonsber gmalhang fth Ileomiation.

the W 2 2=2IT.L 10/16/2012 minormation submitted,,.

to the beat of my knowledge and belief, m^. accurate.

and copt I a SIGNA14pRE OF y1INCIPLE Plant Manager aware that fthm are SgnFican Penalties tor submitting false Wionnatlon.

includng the possiblll of EYCUTIVE OFFICER OR ARENMEAMIDYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Refernene all attachmenta here)1. Flow existed through this outfall 14 of 30 days during the month.rEPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1I61212 PAGE 1 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Wnfleld Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, L 61010 DMR Malling ZIP CODE: MAJOR (SUOR 01) CS 61010 IL0048313 PERMIT NUMBER EO1-0 DISCHARGE NUMBER MONITORING PERIOD MMIDOYYYY I I MMIDDYYYY STORUWATER (FORMER 00lE)External Outhall NODISCHARGE I ...! .... I FROM iI 09101/2012 I Tel 0309012 I-L--I !ATTN: Zoe Cox/ENV SPECFREUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYS E Solids, total suspended SAMPLU E 500 0053010 H5lIT..i ..t m4. -Wpy IRA Solids, total suspended SAMP 28.0 50.0 19 0 01/07 GR MEASUREMENT 0053080 -30 ~ 0 Other Treatment Process Q..-(RAS Complete ____ ____ ____ ____ __ ____Chromium, hexavalent SAMPLE ...........

5 (as Cr) MEASUREMENT Soo 0103210. ._.. ...... _ _Effluent Gross _________

~i- DAPMX Chromium, total SAMPLE ...... --.......(as Cr) MEASUREMENT Soo __"_5 0103410rr- Effluent Gross , EMM __________A

-" Copper, total SAMPLE ... .....5......"500 (as Cu) MEASUREMENT 010 21 .7"." r i'. A....-:;: :.i Effluent Gross -..Iron, total SAMPLE ....... .....(as Fe) MEASUREMENT 500 0104510 -., ., .. .... .., ... [ ..A,- A Effluent Gross _____ a .-7 Lead, total SAMPLE ...... t (as Pb) MEASUREMENT Soo 0105110 .. R ..2 .4 f....... ~ ~..-. '" " : 2: " ..!: Effluent Gross -. -AAV~AIL-Y__

-NAMEMfTLE I certy tnder penalty of law thai th0 domonmud and all ataclhrie wvere prepared under my TELEPHONE DATE P " r OFFRCER drecl or supernimen h accordance wdh a system designed to assu that quaMd personnel preperty gather end evalut the InlormalW suW~osid.

Based an my knquty of fth person or personsa1 0530 Benjamin P. Youman who manage sys=t or thse persons drctly rNsponae for gaMhen the Wntmeon. the 10/1612012 Boitonion Is, to the boe of my Wedpe and befid, true. ecunjp and cogro. Ie am SIGNAWRE OF P CIPLE Plant Manager aware ta there are a6i0cM penalties for submittirt Wee bnomiart.

ftbidin Me ponsitit of EXECUTIVE OFFICER OR AREA NUMBER o PImms e end alnmn r owng AUTHORIZED AGENT CODENU ED.COMMENIS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmenta here)1. There was no discharge ot processed steam generator chemical cleaning wastewater during the month.2. Flow eidsted through this outfall 16 of 30 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1162012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMrIrEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvitle.

IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4460 North German Church Road Byron. IL 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER [DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER (FORMER 001E)External Outfall** NODISCHARGE F-1 ..61010 MONITORING PERIOD"MIDO Y I I MMIDOIYYYY FROMI 09/01/2012 I TOI I ....... I I UW09ruA12 I AlIuI: 40 ___________rm QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel, total SAMPLE ...... 50 (as Ni) MEASUREMENT 0106710 "'2," " -2 A. Dal. GR.AB Effluent Gross '. * < __"__-__ -D,. " *,Y "___"_-__Zinc, total SAMPLE ..... ... 5W (as Zn) MEASUREMENT E.ffluent Gross 1AW A Ratmen clnt 0.530 0.967 3 0. o 02/30 , CN treatment plant MEASUREMENT 5005010 Ra______ IG( Peýr~JMO.5

ýCONTW Effluent Gross __________WT

... DAL SAPL:-' -i.-: " .. ..... ... ..... .7 .Efi, uo t _oss _;_ES I .-.._"* .-.._. ., "..._, ' ...._,"_.....

, SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMdlPLE MEASUREMENT NASAMPLE_._*_ _._ _._*_ _. ..., .._ " -.PRINAL EXECUTIVE OFICRIy unde Py of law Val Mb ocumeaa a unalaaeu were pelaeiin my V TELEPHONE DATE PRINCOAL OF~tER nction or suparnMsIon a mccoiincl WWI a system desigikld asure that quafe pemannel popey gaMer and evalut dhe kdrmnaton Oased on my kquiry ol die persmn or perg s 1 Benjamin P. Youman tno MPna me "Mm of de petm s drecUy rO s les b tar gamreng die norna. to, 815 1431602012 Untom twi Is. to the besg d my true. accwahe. and comlete. I am SIGN6 JRE ON CIPLE_10/62012 Plant Manager saws dia dtm e aw sigWn am n pA l te 10 rig tai99a ia3ma. bUWAlirg the psaifty of EXECUTIVE OFFICER OR AREAN Inne and lrprionmenm fa knowig vlorla. AUTHORIZED AGENT COD] NUMBE M_/DD/____

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attashments here)1. No Closed Cooling System Drain Water was discharged tis month.2. Fire Protection and Service Water System drain water was discharged this month.3. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Cleaning wastewater was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 111/2012 PAGE 2 p 0 4 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER DMR MalHng ZIP CODE: 61010 MAJOR (SUBR 01) CS COOLING SYSTEM BLOWDOWN External Outfall" NO DISCHARGE MONITORING PERIOD MM/DD/YYYY j MM/DD/YYYY LOCATION 4450 North Germ Byron, IL 61010 an Church Road FROM 1 0910112012 I TO!09/30/2012 I l; 2r QUANT11TY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIP Temperature, water deg. SAMPLE ....102.0 0 01/01 CN Fahrenheit MEASUREMENT 0001110 .11 oI ...;W .-'-g.C"" .q, MOn...,.E ff lu e n t G ro ss -." .* .F .-" , ",. , pH SAMPLE .. 8.15 8.60 12 0 01/07 GR MEASUREMENT_____

_________

______ _____004001 0 I5lMI6T-: :" ... .-.- ': "* * .Wehld " GP,,B Effluent Gross -_ *_:_-. , __... " ___ ...- ...___ .-. -Solids, total suspended S .2.0 2.0 19 0 01/30 GR MEASUREMENT 00501 0 -EITP, * ., teq. Mon. Req. Mmn oo0o1 .....Mnt*. G Effluent Gross -E... " ____': ..: .,. ". "0IAAV(. "DAlLYI4X L ___il & Grease SAMPLE ...... ...... .. ..... <3.1 7.0 19 0 01/07 GR MEASUREMENT 0055610 RM..... ....o. o .15.20 Fn GRAB Effluent Gross REQIREEN AV fUY A Chromium, total (as Cr) SAMPLE ....... <0.0021 19 0 01/07 GR MEASUREMENT_____________

_____ _____ ____ _____SA P E..........

..Copper, total (as Cu) MESURMPEN 0.028 19 0 01/07 GR 0104210 .PM07 'It " ,.....',.;RAB.

Effluent Gross * -, " ' i"--i"_ _:"' ....... _Zn.oa(s8)AMPLE

............

<0.0020 19 0 01/07 GR ncpe, total (as Zn) MEASUREMENT 01092 1 0 ,.' W I ..,-Ir... " ..13 .433, ..Effluent Gross .. ..-; .... I.Y MX __I " " Ii, ttl(a .)MAURMN NAMErTITLE I cew*l under ietnall d law Mlat dus docund and al antadwwtns were prpae uncder my TELEPHONE DATE PRIN4CIPAL EXECUTIVE OFFICER d or supennsion iaccrdance with a system designed to assure tht quafifed personneT ,arpedy gather and evatue the information submitted.

Based on my lnquuy of the pemon or perains 1'5 406-3700 Benjamin P. Yournan who manage Me, system, or Vicse pesmn directly rep4 for gathering the Waratonn, the 10116='12 nformat.mn subatmtd Is. to me bes d my knovwedge and betef. true. aimunate, and impmete. Iai SIGaTUR___

PRINCIPLE

s Plant Manager aware that ter are sqgiVficant penanies lot sutenit=tg talse lnlumnmatin.

ncltudig Ma f EXECUTIVE OFFICER OR an 61o1 rine and inpuimmern tor nowing vwrialns.

AUHRZDAET POENUMBER MMIDDIYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Monitoring data for outfall 001-0 is included on attachment EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116A2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMiT"EE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACIIlY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 OMR Mailing ZIP CODE*MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 001-0 DISCHARGE NUMBER I MONITORING PERIOD MM/DD1YYYY I MMIDD/YYYY COOLING SYSTEM BLOWDOWN External Outfall' *" NO DISCHARGE FROM I 09/01/2012 I TOI 09/30/2012 I.QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNIT EX ALOF TYPE____________

> <_ VALUE____

VALUE___ UNITS____

UNITS__ _______ _____ ANALYSIS _____Oxidants, total residual ...........

.. ..........

0.04 19 0 01/07 GR MEASUREMENT 3404410 o ERI4-+- ..,., .. .: -10. "IWY " Effluent Gross .REO IREMI .---" " .. _ ...._._ ..+ ILyMx. ._' _ .--Priority pollutants total effluent SAMPLE500 50008 10 uiqrr Mon. .... Rqq. Mon.Effluent Gross M9 '"_______

'Mon D GRAS Flow. in conduit or thru SAMPLE 1.249 0 1577 242 3"" "..... 0 01/01 CN treatment plant MEASUREMENT 50050.10 o T Req. on. Re% Wm,-... .. C4 :r .:n: -CNT-IN Effluent Gross .F-MB qE V g. ._A .,.+ ._..-._-_.

-. --.... ,, -Chlonne. total residual SAMPLE .........

.... .... S0 MEASUREMENT 50068 1 0 1 0 , ." .... .- .02- "ai W-, .." Effluent Gross Jy -.._ _ _ _- .: .l Y .n -., SAMPLE ..... .5O MEASUREMENT

__ _ _ ___ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ __ _ _ _ _813131 0 ..... Dail " .1..SAMPLE MEASUREMENT

.. -..... ..PRINCIPAL EECME OFFICER rirection or sujpervaiso in accodance ofth a system desiged to assure mhat quablfed pomesanl TEEHONE IDATE property gatner and evalfta Me inforiation sijmItted.

eased on my lnqzM d th pe~on or peisons 8120-70 Benjamin P. VoIuifan who mange mhe systeM. or ftsoe persons directly mspoatt for gathering mhe avltormbn.tht~fe SG RE RNCPE10/1 6/2012 Pat aelo n vutin "ed i. to=the best 01:- ... .. ole. and be.- .true. accrate, and Com .plete. I am .SI .-.. E OFF.ICE OR A Pat mare are s fficaa penalties tor sut ..t..ng I.as itonatinidig the p..si.. d ,,FFICE OR ARA

• B .O TMOR PRIPMES Irme and ownJonment for knowina vigiation.

AUTHORIZED AGENT CODENME MIDYV COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem.)-EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6A212 PAGE...:f Tep (' : "," ..,` .. ., .:, " : " 1 "E'R A: %

0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 winfmld Road Warrenville.

L 60555-5701 FACILUTY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 Ajj"lN- 7rn ".,.,Ivb=NV .PFt DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY I I MMIDDJYYYY STORMWATER RUNOFF BASIN External Outtall***NODISCHARGE J ...I I I _ !FROM I 09/01=2012 J TOI 09/30/2012 I q W ATTN:UNC ZooAMPLE PE QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER EOF TYPE VALUE VALUE -UNITS VALUE VALUE VALUE UNITS ANALYSIS SAMPLE m. ,.Solids, Total Suspended MEASUREMENT

...... .Effluent Gross ,..,'.'> 1 D .. --SAMPLE .. .......Solids, Total Suspended MEASUREMENT 0053080-3010 Other Treatment.

Process w .*..:, , GRA13., '10 Complete ,"________

7 Chromium, hexavalent SAMPLE (as Cr) MEASUREMENT 01032 1 0 -.. .. ..., .....011 .016 ." -iy ..:.-Effluent Gross or, I -;m an'I;, .p.a V. .......- .Chromium, total SAMPLE ........(as Cr) MEASUREMENT 0103410 RERMT PR.A, Effluent Gross ___________

___________x__________

Copper. total SAMPLE ..........(as Cu) MEASUREMENT

.-0104210 -pwE:fIT'f-

...... .-ly GA Effluent Gross AW~ "~- ~ ~ ~ --Iren, total SAMPLE ..........(as Fe) MEASUREMENT 0 0 1.0 -... ... --'. , --1 1 -4G 0104510 Dal " .-.,.:. ;'".m,: t. ..... .-.-."- .f: ? ,.Effluent G ross .-_. .' "..__"

-7.Lead. total SAMPLE ........(as Pb) MEASUREMENT 01051 10 .-003MI.-,':.. ..NAIJTTLE i car*ty und! pnfty di law OW ums domwd and aul anahnnerds were prepared under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFRCER or suparbon in attedance with a Sysem daslgned to assure atd qualfied personnel I XVe0M and evalte fthdiniorm etl rsusbnd e Based en my ro e InW rOr MeM I,.___,..._

815 40&-3700 Benjamin P. Youran who manage Lp e syss. or ase amm- direV:t/ Uio fortgtflithe itn. faste at gO OP n I015 101162012 Infonnafen submitted Is. to mOtes 13 6 51 nowfeMge and bere. tn', acmruate.

and c-Wnete. lai 8IGNA-RE IaimRINCIPLE__

Plant Manager aware m atmere are slgi pkaftt for tOrnnig false IOnnwmau.

induding me p-bbly of EXECUTIVE OFFICER OR NUMBER MMIDDIYYYY TM OR pmn flne and kldptos e for Wwwin AUTHORIZED AGENT COD NUMBERMM/DD/YY

__COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hers)1. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1162012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIIrEE NAMEIADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

U 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 DMR Mailing ZIP CODE: MAJOR (SUOR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD M/DYYvI MMIDDJYYYYY STORMWATER RUNOFF BASIN External Outfall* **NODISCHARGE EDJ FROM I 09/01/2012 I TOI 09K30/2012 I! Il I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF TYPE VALUE VALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TYPE Nickel. total SAMPLE ...... ......(as Ni) MEASUREMENT 0106710 I0.1-ERMr" .,. .. " ... .-..":1 ,. .176 .." Effluent Gross ....IRLY: 1 0 'Zinc, total SAMPLE ......,,*(as Zn) MEASUREMENT 0109210 PERMIT ,.... .n.q..m .047 .26 Effluent Gross _r___RE_ _ __._,__. ,. ,_", .." 3OPA AVG DAILYNMX GRAB Oil and Grease SAMPLE ....MEASUREMENT EffluentGross B.EQUIRElE

". .l,. 15 Mx Flow. in conduit or thru SAMPLE ......treatment plant MEASUREMENT

......5005010 .ERI Req m.on .Req..Mon..-.

,..., ., -Whefn A Effluent Gross 7 WhenAAV -" ;.... " " .ischagig

.-SAMPLE MEASUREMENT SAMPLE MEASUREMENT

l-rEo u rrlma "--, ., .. ...".- .:;: -"-, -::... ..3UN .... ...... ... ..: :...SAMPLE MEASUREMENT PERMIT .. -.." ..NCALECIE ify under penalty o law tus edocumen and aft attnaunems were prepared uner my TELEPHONE DATE PRINCIPAL EXcuTVE OER di suPe in aoance with a system design to assure y quaffTed peTonnel proper gather and evakfle the Informiationi submitted.

Bsed an my Inquiry at the perewor persosaftJ~L

~ .15~ii~i BenjaminP.Youan who manage the system, orhose prsms dlcby rsnssbel orjgathae Uin the nm, _ 406-370011at1onth infoImation submitted is. to fte beef o my Ietaatedge and betef. true. accurate.

and corr ef I am SIGNA OF e RINCIPLE 101/2 Plant Manager aware at there awe s91flcer pnaloties or Subtl9iftg false infomation.

indudin ae possibliy of EXECUTIVE OFFICER OR U EMA IYMw 1 e and Imptsnaunn (O u vwotatn. AUTHORIZED AGENT coDNUMBER MM__D_/Y__

Y_COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/6=2012 PAGE 2 0 0 4 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit Mtf0048313 September 2012 Page 1 of 3 MONITORING DATA: WBD C WBD Flow Rock River DATE Temperature mgd Flow deg F cfs 09/01/2012 102.0 21.42 1,440 09/02/2012 99.0 16.63 1,450 09/03/2012 101.0 10.50 1,520 09/04/2012 101.0 19.32 1,570 09/05/2012 101.0 11.26 1,620 09/06/2012 93.5 0.010 1,550 09/07/2012 n/a 0 1,570 09/08/2012 91.6 12.62 1,530 09/09/2012 91.6 19.17 1,580 09/10/2012 94.0 24.29 1,590 09/11/2012 96.1 17.98 1,580 09/12/2012 99.1 13.72 1,580 09/13/2012 99.1 13.23 1,480 09/14/2012 92.1 18.01 1,500 09/15/2012 92.1 16.78 1,500 09/16/2012 93.7 15.95 1,520 09/17/2012 93.7 14.51 1,540 09/18/2012 91.5 16.85 1,510 09/19/2012 86.5 14.65 1,560 09/20/2012 92.7 15.91 1,620 09/21/2012 88.5 16.02 1,410 09/22/2012 87.8 17.11 1,550 09/23/2012 85.2 18.36 1,640 09/24/2012 85.4 14.37 1,600 09/25/2012 91.6 18.47 1,510 09/26/2012 91.6 15.92 1,470 09/27/2012 89.6 15.97 1,590 09/28/2012 90.3 15.46 1,580 09/29/2012 91.0 18.10 1,480 09/30/2012 91.0 14.65 1,440 K:\BYR_CH\BYRON.DB\CIerk\Monthly Discharge Monitor Rpt\2012 Reports\September\September 2012 ATTACHOI .doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 September 2012 Page 2 of 3 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of September 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 29 of 30 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 28.0 mg/L on 09/10/2012.

The CWBD TSS value was 2.0 mg/L on 09/10/2012.

5. Rock River flow was <2400 cfs in September 2012 therefore daily temperature calculations were required during this time period. (Special Condition 12). Per Special Condition 12, in the event the Rock River flow is<2,400 cfs, daily calculations will be undertaken to demonstrate compliance with the water quality standard.

The calculations are based on hourly measurements, averaged over a 24-hour calendar day for Rock River flow, main Rock River temperature, CW Blowdown flow, and CW Blowdown temperature values. Results of the calculations shall be reported in the DMR on a monthly basis. Calculation results are in the table on the following page.6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in September 2012. (Special Condition 15).K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\September\September 2012 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit 1L0048313 September 2012 Page 3 of 3 Date Average Average Average Average Calculated Water Quality Rock CW M/U CW CW Temperature Standard River Temperature Blowdown Blowdown at edge of Temperature Flow (F) Flow Temperature mixing zone (F)(cfs) (gpm) (F) (F)9/01/12 1440 74 11971 97 75.2 90 9/02/12 1456 72 11983 99 73.4 90 9/03/12 1513 75 11971 100 75.6 90 9/04/12 1577 77 12038 101 77.9 90 9/05/12 1615 77 1658 96 77.5 90 9106/12 1544 81 0 N/A N/A 90 9/07/12 1570 80 1175 89 79.8 90 9/08/12 1531 75 14546 92 75.9 90 9/09/12 1571 73 14904 91 74.2 90 9/10/12 1593 74 15200 89 74.4 90 9/11/12 1577 73 11321 95 74.2 90 9/12/12 1578 75 10421 97 75.4 90 9/13/12 1487 73 10421 91 73.2 90 9/14/12 1508 69 11258 91 69.5 90 9/15/12 1498 71 11229 93 71.6 90 9/16/12 1521 71 11213 93 71.7 90 9/17/12 1538 70 11188 93 70.8 90 9/18/12 1518 68 11204 88 68.5 90 9/19/12 1557 65 11221 89 66.2 90 9/20/12 1621 66 11208 90 66.4 90 9/21/12 1417 64 11225 88 65.4 90 9/22/12 1537 61 11233 86 61.7 90 9/23/12 1633 60 11925 85 61.0 90 9/24/12 1609 58 11563 88 59.3 90 9/25/12 1516 60 11583 92 61.0 90 9/26/12 1472 62 11629 91 63.6 90 9/27/12 1574 61 11642 88 62.2 90 9/28/12 1586 60 11650 89 61.0 90 9/29/12 1487 61 10342 91 62.3 90 9/30/12 1450 62 12171 90 63.3 90 K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\September\September 2012 ATTACHO1.doc Exeikn.Exelon Generation Company, LLC www.exeloncorp.com Byron Station Nuclear 445o North German Church Road Byron, IL 61olo-9794 November 26, 2012 LTR: BYRON 2012-0123 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of October 1, 2012 through October 31, 2012.On 10/06/2012 at 11:20 hours a leak was discovered on the piping for the temporary mechanical draft cooling tower equipment.

The plastic pipe fractured and water flowed from the crack at an estimated 5,000 gallons per minute. The majority of the water was retained by sandbags and the leak was isolated at 11:27. Approximately 30,000 gallons overflowed the sandbags and entered Woodland Creek via storm water Outfall 003, East Station Area Runoff. Analysis results of a sample of the cooling tower water obtained prior to entering the storm water ditch are summarized in the following table: pH I Copper (mg/l.) I Zinc (mg/.) I Chromium (mg/L)8.68 1 0.033 0.0181 <0.0021 The remainder of the leaked water was pumped back into the Unit 2 Natural Draft Cooling Tower basin.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Benj ouman Plant Manager Byron Nuclear Generating Station BPY/DS/eh Attachments bcc: Jennifer Gould -Environmental

-Cantera (electronic)

Zoe Cox -Environmental

-Byron I-0 0 LI Lt a cc wz r z Iw cc 0 I 0 9 i w z w a I N I LU 01 0-i o -d~wU~d~j'g liii hI Z RI to-.

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555.5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. L 61010 DMR Maeing ZIP CODE: MAJOR (SUHR 01) CS 61010 I 1-L0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD I MMIDDJYYY I MMIDO(YYY DEMINERALIZER REGENERATE WASTE (0011A)External Outfall***NO DISCHARGE

[ **! _ _FROM I 10101/2012 I TOl I I _ _ I 10/31/2012 Il lI NATIONAL POLLUTANT

[ GE ELIMINATION SYSTEM (NPDES)

REPORT (DMR)61010 PERMITTEE NAMEJADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 ATTN: Zoe Cox/ENV SPEC DMR Mailing ZIP CODE: MAJOR (SUER 01) CS I L0048313 PERMIT NUMBER B01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDIIYYYY

_j I MM1DDfYYYY SP PLANT EFFLUENT (FORMER 001B)Extamal OutUl-" NO DISCHARGE F-1 FROMl 10/01/2012 I Tot 1013112012 Il I II I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS E BOD, 5-.Day SML (200.74 0.96 26 16.0 23.0 19 0 02r30 24 (20 Deg. C:) MEASUREMENT 0031010 sný 10.5 ,.2 TWI~9tR Mnt -vQqMM Effluent Gross ~~B A. 2~LZ~aL* .~PH .... .-7.51.. 7.61 12 0 02/30 GR MEASUREMENT 00400 1 0 ,.-_ .' "" ' : -i-. ..., ... ...Effluent Gross ALL UMM -, *!,.' -SAMPLE Solids, total suspended MEASUREMENT 021 0.32 26 4.3 7. 0 0230 24 00530.10 .-, -,. -. , ....,, ' :. ....Effluent Gross oEWIIW -. 1-,w Mm ~t~ ____Fow in conduit or th....A..E.......

0 01/01 CN treatment plant MEASUREMENT 0.0 _ _ 0_00_ 3_001_1__5005010 o W4 '-: ' 4.eq, o

-..--* "

-.,,,-A._~ Ft. ... ...Effluent Gross I". ... N .-- ...-;- " -* "' ".SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT IRU ___ __ __ --* , -. " .,.NAMEI'lTLE I ceGOy under penalty d law 0a 016 doslme and a11 were prepared un R TELEPHONE DATE PIRINCIPAL EXECI~LVE OFFICER Aontn or supenion c ac arnce with a syame designed to assure da quated persnnel Preer gather and evakta die Irdonmatim submmlat.

Based on my quWt at the poeran o persons 815 406-3700 Benjamin P. Yournan who mamae the aYStemo thda. permons directly respaosle for gathenl t Infomalna.

the 11/19/2D12 iroimation

a. tothe best almy owxle and bele. true. a=zu- and ompieta ,am g aE 4NA PRINCIPLE Plant Manager aware tha Viere m s1nWCant ar odmtbM. dg the poLnstd EXECUTIVE OFFICER OR N EM Yow ,Jead Io nwn voan.AUTHORIZED AGENT CODE NUMBER M__ D______COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Flow ekisted through this oulfall 31 of 31 days dunng this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11612012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIlTEE NAME/ADDRESS NAME Exalon Generation Co., LLC ADDRESS 4300 Winfifld Road Warrenvilie, IL 60655-5701 FACIITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 1L0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS WWTP (FORMER 001C)External Outfall"* NODISCHARGE 61010 MONITORING PERIOD MMIDD/YYYY I I MM/DDJYYYY I I 4 FROMI 10/01/2012 I Tol 10/31=12 I ATTN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids, total suendedS..

.... 9.4 9.7 19 0 02130 24 So~ls toalsusened MEASUREMENT 0053010 t.1*5R~4 4pen4' j m t' Tw'~r~fiCM2 Effluent Gross ft_-.?. .. " -. ......Chromium, hexavalent SAMPLE (as Cr) MEASUREMENT 500 0103210 " .eg." " ".. " Effluent Gross Chromium, total SAMPLE .. .....(as Cr) MEASUREMENT Soo 0103410 ":'" .flt:;" " :l G" Effluent Gross RA.

t3j a.r ! 4 .' :" -Copper, total SAMPLE .....5 (as Cu) MEASUREMENT Soo 0104210 ". -". .1, ! 4-'. .n" r.$ '1"- -.Effluent Gross -SWJRMEr 2pi ;wAAva.- tAY~~.'e'Iron, total SAMPLE ...... .-me.......(as Fe) MEASUREMENT SIX0 Effluent Gros .____ -P' ';x UfS. .Lead, total mS.AMPLEese

• ~n 0 (as Pb) MEASUREMENT s____ ______________

____ ___0105110 M'I1/2T-,..:

s "a". M. A $ R Effluent Gross A.M -IM bM4..

.. L2 __.,-- 9. , .aE e , ' : -Nickel, total SAMPLE ........ .(as Ni) MEASUREMENT SIX0 01067 1 0 :"< -.-" ;- -tý- -" "1 -.i .4 -. ...vng- .. .-0 .i,,,'" Effluent Gross I- -.*... ., ,'- .:...Ni kel, TT toa.APE ... .......NAMVFlITE I cedy w1der pnally of law mat dcment and an anacdnwn -09 prepared undjr my PRINCIPAL EXEOnVE E dream w sjpeu sin f accriene ui asyem essns tor a ist quae- e i TELEPHONE DATE PfOyV aue am evah"ftrdmkvfon asubadeal.

eas an x %my at the epersons lxmm---81 063 Benjamin P. Yournan who anac the sysMO P 0e r Msy Maspe trg Owm1nfuri me a m" ) 615 406-370011/19/2012 Mlonmat sumitted is. to the best o my mo ,edge and beoS. tnsee and compe. I am SIGNATIRE OF I/C9IPL2E Plant Manager aware ha Stre am significarn peae Im subm ase innatim, kb te s E T OFFICER OR AREA ibispfnw r and bpnpibhwnien for knonbi sianw EXCTVJFIE R UBRMIOY iwm rums nmvI AUTHORIZED AGENT CODENMR//_

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Roference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outlali 14 of 31 days during the month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/6/2012 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT'EE NAME/ADDRESS NAME Exelon Generalton Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road IL0048313 PERMIT NUMBER I C01-0 DISCHARGE NUMBER MONITORING PERIOD M"OrYYY I I MMIDD1YYYY DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS WWTP (FORMER ODIC)External Outall**NO DISCHARGE 3.61010 FROMI 10101/2012 TOI 10/31/2012 I II II I I Byron, IL 61010 ATTN: Zoe Cox1ENV SPECFREUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS O F TYPE Zinc, total .. ....500 (as Zn) MEASUREMENT Soo 0109210 1._Wa.. ai Effuent Gross J __,___. _.. -__ .- .. .. .--...;..Row, in conduit or thru SAMPLE treatment plant MEASUREMENT 5005010 PERIyIT.-

Rgq.Mqn .Req. ...-.-. .... ........ --E~ffluent Gross , --SAMPLE MEASUREMENT , * .R5'IIM W ... -,.___.. ....___ ____! / ......~ ..S _____.____..

_ __...______-" ... SAMPLE MEASUREMENT

____________

• MEASUREMENT

.__,___"______

' .'" .: ..-. ...,.L.- ..-. ; .. ...SAMPLE MEASUREMENT

_ _ _ _ _.__.__ _ ..E, ..EW. -i .: _. _ __.._ ' _ ..... ._.-__ _ _ __ _ _ __ _ __ _ _ __ _ _ _ _-______.-

.q ....SAMPLE MEASUREMENT--

-_: ...-- --. ' , ; .... .__..... ...A........_

_ __ _ _NAMEI1TLE cerUy unde penarly d of taw Me do doument and an atactunants wwe preared under liy TELEPHONE DATE PRINCXPAL EXECU1hVE OFFRCER or upervisi in accdance with a system designed to assure tda quafied personnel ,rlegatherand evalue te inknnatin submittd.

Based an my hquiry of the person or penisons81 0630 Benjamnn P. Youman m manage the syste or those persns diecty respsbe for game"i the iymbon. the N E , 815 1i406-3700 11/1912P12 Informan submitted is. to te best of mi Ismatedge and Inbef , acurate. and conpIbea SIGNARE OF MNCIPLE_Plant Manager aware o taere a sigricant penalis for submitting talse ifomati inclutin pOssiity d EXECUTIE OFCER OR AREA am a and pun t bwag w AUTHORIZED AGENT CODE NUMBER _ MDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1162012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIrIEE NAMEIADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warenvie,'lL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 OMR Mailing ZIP CODEt MAJOR (SUBR 01) CS 61010"- 1.0048313 PERMIT NUMBER D01-0ý DISCHARGE NUMBER MONITORING PERIOD MMWDDIYV I MMIDD/YYYV RADWASTE TREATMENT (FORMER 001D)Extenal Outfail"**NO DISCHARGE "J FROMI 10101/2012 TIT 10/31/2012 I I lIt I I 0 NATIONAL POLLUTANT DISCHARGE EUMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exeton Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I lL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER[ MONITORING PERIOD MMIDDIYYYY I MMIDDJYYYY STORMWATER (FORMER 001E)External Outfall*" I NO DISCHARGEr FROMI 10/01/2012 1 TOI 10/31/2012 Il I! I Byron. IL 61010 ATTN: Zoe Cox1ENV SPEC ____________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX FrTYPE>< ANALYSIS Solids. total suspended SAMPLE 500 MEASUREMENT_____

_____ _________

_______________

_____005310 4q~T- n1 GRAP Effluent Gross RE M .'E * ... .M r D, 4' , .- A ": 4 ." SAMPLE ...... 29.4 48.1 19 0 01/07 GR Solids. total sused MEASUREMENT 0053080- ., ...Other Treatment, Process RNT.*.- 3 1 complete .-;z~"., Chromium.

hexavalent SAMPLE ...... 500 (as Cr) MEASUREMENT oim io -,,:",.:-

!. -*. **.. ...' ..*-,.Effluent Gross

• __________

.* ____Chromium, total SAMPLE ...... 500 (as Cr) MEASUREMENT Copper, total SAMPLE S.I... ...,5 (as Cu) MEASREMENT 0104210 e'lM" .." .-_ .. ..GR..Effluent Gross Iron. total SAMPLE Soo.. ...... ..(as Fe) MEASUREMENT 0104510 "RE D Effluent Gross REQ JIREME .. ., .., .". ..:,._, ..--', -.;D m .Lead, total SAMPLE ................

500 (as Pb) MEASUREMENT Effluent Gross firEQUIREMT-

-NAMEittLE I ceitly under penalty of law gho ft domumner snd ag anadrmnlits were prepated under mi J TELEPHONE DATE PRWWCAL EXECUTrIVE OFFICER dwmcmo W suers ,n =0,d,=c w a system "eO~ed to assthe Wellafied Munelou propedy gether and evablte fthinformation sutimld. Based an my inquiry of the person or per8son Bejmin P. Youan who manage the sm or those persons dWcly responsrbe for gathering the infonathon, the 11/191M12 kdonnadon sul~ b e s, to Me besg o my bnw belie, nMo. aca nte, and *onmel e I am SlGNAO E C F INCP L Plant Manager aware tat me are s9inicant penahes tar submalung ese bdonnadon, bidug the pobrdy of EXECUTIVE OFICEOR N EEA.. ON line and bpsnsusf ohtq violatns.

AUTHORIZED AGENT CODE NUMBER MMDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmenta here)1. There was no discharge of processed steam generator chemical cleaning wastewater during the month.2. Flow existed through this outfall 4 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6I2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-O DISCHARGE NUMBER MONITORING PERIOD MMIDDIYYYY IMMIDDIYYY STORMWATER (FORMER 001E)External Outfall***NODISCHARGE EJ FROMI 10/01/2012 I TOI 10131/2012 I I I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF Ap VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Nickel. total SAMPLE ....(as NI MEASUREMENT 0106710 11u -'. ...1 2 " .D GRAB Eff luent Gross ~~'.~-~ .i-& -Z-~~ ~~' ___Zinc. total SAMPLE ............

....(as Zn) MEASUREMENT 0109210 , ;".-. ,.. V .Effluent Gross ,JqEEI- .-, _"_..._" _'""-*Flow, in conduit or thru SAMPLE SpalM A U E E T 0.219 0.356 3 ..-.......

• "**~ 0 02/30 CN treallment plant MEASUREMENT Effluent Gross 7*_____M ~::>er* ...SAMPLE MEASUREMENT

-_, .-. ., -, .-- .. -.;--: .:.; ......i.- -._ _-SAMPLE MEASUREMENT

________ ____ ______ _ _ _ _ __ _ _ _ EQUIREBBEI

.. ;-. .I.. .-. .:-. -.-,,.,... :..-.. ;.... ., ....... -.,.SAMPLE MEASUREMENT SAMPLE MEASUREMENTq le .,. ., .,.. ::,/., ,. ,.,-:....

..... .. ...... ....... .... ........-.

...... a.".-.. .__.,__.._..___..

...:. .._ __.._.__....*

.: .-. " ., ,,. .' ,.. .~ d ..:... £. .: ..- .,. ....-.. ..: .., .,.PRINCIPAL EXECUTIVE OFFCER :irectim a s in accorance wah a system dTELEPd to aNsure VW Oaied pDmAel pmpeuy gather and evjt the Wdmmabi snrumbmd.

Basedn my kquIYal iPetib l m , ,,- 815 me6-37 1s or Benjamin P. Youran who manage tha syston or ume persons directy responsbe tar gathaertng the inkiomal, ir 11/11212 information t is. to Male best d my awdege and beielf. true. accursM and complete, SI GNA aE OF P %jLE Plant Manager aware thatl ere are significar pona for submittig talse nfomatim.

bkiin Me posstily l EXECUITIVE OFFICE R N BMDAREA TVM0"FF~rW pn and inprmmimman for knowing vidaions.

AUTHORIZED AGENT COD NUMBER MMIDDIYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Closed Cooling System Drain Water was discharged this month.2. Fire Protection and Service Water System drain water was discharged this month.3. No Turbine Buildina Fire and Oil Sump or Generic Non-Chemical Cleanina wastewater was discharged this month.EPA Form 3320-I (Rev 01106) Previous editions may be used. 1/6/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 DMR Maeling ZIP CODE: MAJOR (SUBR ol) cS 61010 I IL0048313 PERMIT NUMBER F- 001-0 DISCHARGE NUMBER MONITORING PERIOD MMJDDJYYYY

_ MMIDDIYYYY COOLING SYSTEM BLOWDOWN External Outfall* " NO DISCHARGE J *I .......FROM I 1010112012 ITOI 10/31/2012 I I I i T--! !ATTN: Zoe CoxIENV SPECFREQUEN_

_QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. SAMPLE PARAMETER OF TYPE" VALUE VALUE. UNITS VALUE VALUE VALUE UNITS EX ANALYSIS Temperature.

water c1eg. SAMPLE ...CN..........92.1 Fahrenheit MEASUREMENT 0s q .M * .Effluent Gross : :; .......C.. .-TI .SAMPLE 829 8.58 12 0 01/07 GR MEASUREMENT 0040010 .EljMIT ' .... -..,.6. .. .9 Effluent Gross " .Tjj " ". _ ,,,_. "U .Sos, total suspended PLE ..... 5.6 5.6 19 0 01/30 GR MEASUREMENT 0053010 4'-!,T ,., .. .. 1 i.-" -q.4'. e Effluent Gross 11 In___________________

Oil& Grease SAMPLE <1.4 <1.4 19 0 01/07 GR MEASUREMENT 00556110W"T Effluent Gross _________

M. -,

M, i* .. .______."_Chromium, total (as Cr) SAMPLE .... ... ... ..... .<0.0021 19 0 01/07 GR MEASUREMENT 0103410 .-'.:., -* ...".. ..6.Effluent Gross BEQUIREIEMT-.

.-'..- 31 ....._, -Copper, total (as Cu) SAMPLE ...... 0.030 19 0 01/07 GR MEASUREMENT 0104210 P 0.071R.i Effluent Gross REQUIREMENT " , " " " .' I ". ':,'". " " ..... ".....Zinc, total ( Zn) SAMPLE ....... 4.002 0.004 19 0 01/07 OR MEASUREMENT 0109210 ,REW -, , .., ..*.*.. " '.., .214. .. 3 --Effluent Gross .RE IREME .,- .. ., .

.... -.NAMEnTLE I cW* under peakMy 0 law go this doOument and au atachments worw prpamd under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFRCER or surs in accodance with a system designed to assure dud qualifed pensornel propetly gather and evahne the Inaimafdwtm su s'my bqxy d do peso1815n or6perso1 406-3700 Benjamin P. Youman who manage we system. r m.of diecey rspmsbe for gathering me -f1m-a -11/19/2012 information aftnated is. to go beat di my bwmtledge and b"ie, tre. accurate.

and co;p'-s. lamn SIGN OURE 0 CIPLE Plant Manager awam that mtm am significan penaes for submitgin abe IkdonmaT.

Including th possiblily d EXECUTIVE OFFICER OR AREj I nR ome and nprisuiamen for itrar, ong VIOIamenL AUTHORIZED AGENT CODE NUMBER MMDD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. Monitoring data for outfall 001-0 is included on attachment EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6=2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMIJADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, L 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 DMR Mailing ZIP CODE: MAJOR (SUOR 01) CS 61010 I IL004831 3 PERMIT NUMBER 001-0 DISCHARGE NUMBER MONITORING PERIOD COOUNG SYSTEM BLOWDOWN External Outfall* " NO DISCHARGE FROM I 100112012 ITOI 10/31/2012

! I i I QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY* OF SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX NO TYPE SAMPLE ANALYSIS Oxidants.

total residual MASURE 0.04 19 0 01/07 GR 3404410o : " ...10 _ _ _Effluent Gross RE ..-'P w Priority pollutants total effluent MEASUREMENT

.500 5000810 MT.- Req Mon. -_.... ., P, Re.7711-Effluent Gros x e m B .-; .2.,L 1. W.o.y i ( ,:5 Flow. in conduit or thru SAMPLE treatment plant MEASUREMENT 5005010 1 .. -..;..'.,. -., ,n.- .Effluent Gross AW irM 4 .CONTI Chlorine.

total residual SAMPLE MEASUREMENT Soo 50060 10 '.'t~r p ~ ~> ~%...-. -ec 1 ___Effluent Gross .N-. ,__ , .:, .- .,: .-...[ J-y MX. ". L,:. : ,_.. .".SAMPLE ......t-ydn MEASUREMENT 500 8131310 4 M._ .-,,- ... .. ._ " .- .0. .o ..027 -Da""y- Whn Effluent Gross .U. ...' .* .-.. , ..,V " , .RAG SAMPLE -MEASUREMENT

_____"__"___R__IT'___',,_ :" :: " m.~..L ... " ;'~ " ~ ~ .SAMPLE MEASUREMENT

___ _. ......_ E UIAY -'..... t --,- .... ....'NAME/IAMPLE PRINCIPAL EXECUTInVE OFFCR directimo or sipemin acmoance wit a systwni iesied to do quaffed pam -d TELEPHONE DATE Benjamin P. Youmnan Prcpaltr oatim amd evalita the bionnabat slaultad.

EBaed an frev inquiry d die peis or perms 81 40ii-3700 who manage Ow systemn or Sose permns directly MepwUD lot gadfltng the tntonmaton.

f IG E OF 1119/212 Plant Manager inml onaion subrnabd is. to Me best ol my nowaledge and oewl. e and cmpete, lam E V C_ OR_6111110M=__

Owlhatm ___a_ ____P_ for suIT_____

fa___ __ WMn the _ al EXECUTIVE OFaICER OR AREA NUMBER MMD_IIt penafan ad bwftsionl lor knowing vPS. AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)EPA Form 3320-1 (Rev 01/06) Previous editmis may be used. 11612012 PAGE 2 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES DISCHARGE MONITORING REPORT (DMR)PERMrrTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 IL0048313 PERMIT NUMBER 002-0 DISCHARGE NUMBER;)DMR Mailing ZIP CODE-MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfan 61010 I MONITORING PERIOD I MMI/DWYYYY ITO F MM/DD/YYYY I FROM I I 10/01/2012 10/31/2012 I~NO DISCHARGE

=w j -QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS SIS TYPE S o i s o a d dS A M P L E. ..,. .,, .. .Solids. Total Ssend MEASUREMENT 0053010 ..-...' -. GRAS Effluent Gross w,4+ !l, ; -, ,., Solids. Total Suspended EAUMLE 00530 8 0 .' , ,, .*.*,,'.,. ..-." ... ..q *..

.-. ..-..., .Other Treatment Process V', Chromium, hexavalent SAMPLE .......(as Cr) MEASUREMENT 0103210 ....... -..* : " p Effluent Gross I's .j"41 akka-- t e' _____Chromium, total SAMPLE .......(as Cr) MEASUREMENT

__0103410 * ,.Effluent Gross JWQ______U

-*1'II Copper, total SAMPLE....(as Cu) MEASUREMENT 01042 10 "U+ .. ..0 ..'.2M .:: ..041 *:: .+ +.. :l , Effluent GrossO " Iron. total SAMPLE .........(as Fe) MEASUREMENT 0 1 0 4 5 1 0 , .' -.."' ..., -.l .-Effluent Gross GRAUIRE], T _____. ___ ....Ct2.... ._. .. ....'-Lead, total SAMPLE ....(as Pb) MEASUREMENT 01051 10 `-PARRMIToly

.RA Effluent Gross -V." Q6~ .AIY4 NAMEITILE I certify under penaly of law dd fts documern and ag aeanacmes were piepared under my TELEPHONE DATE PRNCIPAL EXECUTIVE OFRCER irectin or supeemion In accordance with a system designed to assure that quad Persnne property gathe and evalute fth infrmatian submintted.

Based an my mwqus d the person or pesrtsona40-70 1/91 Benjamin P. Youman who manage the system. or thse persons durctly responsmft for gatherngM Me infarmation, the asulnmned is. to the best of my knoedge and beief, true. scrals. and complete.

Iani SIGNAU RE OF NCIPLE 1 Plant Manager aware that tere are sGnificant penahes for submitling labse Inimatio.

Mckn fte poasibrily al EXECUTIVE OFFICER OR AREA r OR pHRIM i and k~iSnnMlfll for knowing violation.

AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. No Turbine Building Fire and 00 Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01106) Previous editions may be used. 1/6/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvile.

! 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010 A"rTJ. -1%" ML CQDar" I L0048313 I PERMIT NUMBER FR N002-0 1 DISCHARGE NUMBER I MONITORING PERIOD MMIDDIYYYY MMIDDIYYYY DUR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outtanl***NO DISCHARGE

[J 61010 I._FROM I 10/01/2012 I I Tot 10/31/2012 IlQUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE__________

_____ __________

_____ _____ ANALYSIS TP Nickel. total SAMPLE ..........

...(as Ni) MEASUREMENT 0106710 "P .... '" .011 -.176 .... .Effluent Gross .. .Ai-.- ' -.-'- .., -. 77RA8 Zinc, total SAMPLE ...(as Zn) MEASUREMENT 0109210 0~~T.047 Effluent Gross DeEwIJIID " " .: .-0i and Grease SAMPLE ......MEASUREMENT 0358210 "*- .. .: w ."N' pis ...--.Effluent Gross IM Mg~Whn Flow, in conduit or thru SAMPLE -- ...- ..........treatment plant MEASUREMENT 5005010 R rg8 -T , .--,.'*:.' .: , ; ".q,#M.^.

Whqp Effluent Gross -IBEQUIREMEN7

.,W :P. , ..' ....sc1rgl ..SAMPLE MEASUREMENT SAMPLE MEASUREMENT REUIR .* ....t,, .... *SAMPLE MEASUREMENT NAmErmnn.E I cenily under penatty d law that thits dcwime and ag atadiments were ppatled under my TELEPHONE DATE PRINCIPAL EXECUtlVE OFFICER ecwion o, suMW macadence with a system designed to assure that qualfied personnel Poperty gather and evaa the domnman submitted.

Based an my InqWry d the person or persons Benjamin P. Youman who manage the system those pers drectly resmnpae for gatherg the lnImaonell.

the m OF CIPLE 11112012 Information sub is. to te best cd mi kwledg eand b"e. uie. accurale.

and completI.

1 Plant Manager aware at there are slWgn, caM penafts for suhnitting false indomam wkdg the pasasbsi EXECUTIVE OFFICER OR N EM Y , oR !.. lnprabdtmkent for knowIng vkLatains.

AUTHORIZED AGENT CODE NUMBER MM__ /DD_ _COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. This discharge point was not used this month.2. There was no discharge of processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 11582012 PAGE 2 S L ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 October 2012 Page 1 of 3 MONITORING DATA: CWBD Rock River DATE Temperature mgd Flow deg F cfs 10/01/2012 89.7 16.53 1,520 10/02/2012 89.2 17.71 1,530 10/03/2012 89.9 16.99 1,450 10/04/2012 91.8 17.62 1,550 10/05/2012 91.8 18.17 1,550 10/06/2012 83.4 18.70 1,450 10/07/2012 81.2 17.50 1,420 10/08/2012 82.3 18.01 1,580 10/09/2012 81.9 13.78 1,550 10/10/2012 78.8 15.67 1,450 10/11/2012 78.9 18.82 1,600 10/12/2012 78.9 17.59 1,450 10/13/2012 78.9 21.09 1,500 10/14/2012 90.8 21.01 1,790 10/15/2012 89.1 13.78 1,820 10/16/2012 82.1 17.26 1,820 10/17/2012 84.6 17.34 1,930 10/18/2012 82.2 18.0 2,220 10/19/2012 80.1 16.21 2,050 10/20/2012 79.7 23.59 2,200 10/21/2012 77.5 17.88 2,160 10/22/2012 90.3 13.60 2,130 10/23/2012 90.3 16.17 2,430 10/24/2012 91.8 16.73 2,820 10/25/2012 92.1 19.90 2,860 10/26/2012 79.4 19.11 2,750 10/27/2012 77.9 23.52 2,710 10/28/2012 76.1 19.37 2,590 10/29/2012 73.7 15.88 2,500 10/30/2012 72.8 18.13 2,460 10/31/2012 74.9 21.30 2,440 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\October\October 2012 ATTACH01.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 October 2012 Page 2 of 3 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of October 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 13.6 mg/L on 10/08/2012.

The CWBD TSS value was 5.6 mg/L on 10/08/2012.

5. Rock River flow was <2400 cfs in October 2012 until October 2 4 th therefore daily temperature calculations were required during this time period.(Special Condition 12). Per Special Condition 12, in the event the Rock River flow is <2,400 cfs, daily calculations will be undertaken to demonstrate compliance with the water quality standard.

The calculations are based on hourly measurements, averaged over a 24-hour calendar day for Rock River flow, main Rock River temperature, CW Blowdown flow, and CW Blowdown temperature values. Results of the calculations shall be reported in the DMR on a monthly basis. Calculation results are in the table on the following page.6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in October 2012. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\October\October 2012 ATTACHO I.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 October 2012 Page 3 of 3 Date Average Average Average Average Calculated Water Quality Rock CW M/U CW CW Temperature Standard River Temperature Blowdown Blowdown at edge of Temperature Flow (F) Flow Temperature mixing zone (F)(cfs) (gpm) (F) (F)10/01/12 1,520 62 12246 89 63.1 90 10/02/12 1,530 61 12304 90 62.2 90 10/03/12 1,450 62 12283 90 63.4 90 10/04/12 1,550 61 12254 90 62.2 90 10/05/12 1,550 57 12321 83 58.0 90 10/06112 1,450 53 12225 81 54.4 90 10/07/12 1 420 52 12167 82 53.5 90 10/08/12 1,580 52 11838 79 53.1 90 10/09/12 1,550 52 9750 79 52.9 90 10/10/12 1,450 52 12750 75 53.2 90 10/11/12 1,600 51 12713 77 52.0 90 10/1212 1450 52 12754 76 53.2 90 10/13/12 1,500 .54 12883 81 55.1 90 10/14/12 1,790 57 13142 86 58.2 90 10/15/12 1 820 55 12229 79 55.8 90 10/16/12 1,820 55 12408 83 56.0 90 10/17/12 1,930 57 12204 84 57.9 90 10/18/12 2,220 54 12217 78 54.7 90 10/19/12 2,050 54 13013 77 54.7 90 10/20/12 2,200 54 13046 78 54.7 90 10/21/12 2,160 54 12229 81 54.8 90 10/22/12 2,130 57 10513 88 57.7 90 10/23/12 2,430 58 13242 89 58.8 90 N K:\BYR._CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\October\October 2012 ATTACH01.doc Exelon.Exelon Generation Company, LLC www.exeloncorp.com Byron Station 445o North German Church Road Byron, IL 61010-9794 December 17, 2012 LTR: BYRON 2012-0133 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of November 1, 2012 through November 30, 2012.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Benjai ouman Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments K~r V t ,-bcc: Jennifer Gould -Environmental

-Cantera (electronic)

Zoo Cox -Environmental

-Byron 0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIF-rEE NAME/ADDRESS NAME Exblon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 DMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONIrORING PERIOD-D/YYYY j I DEMINERALIZER REGENERATE WASTE (001A)External Outfall**INODISCHARGE EJ FROMI 11101012 TOI 11/30/2012 I I I ATTN: Zoo COXIENV SPEC _________QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER EXOF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX AAL TYPE Solids, Total Suspended MEASUREMENT -r..3.6 <.7 19 0 01/30,_ 08 Effluent Gross -A POW. -Chromium.

hexavalent SAMPLE 5....(as Cr) MEASUREMENT 01032 1 0 "J ..Effluent Gross Chromium, total SAMPLE Soo (as Cr) MEASUREMENT 0103410 ... ..- 7 7- a, .... ,. ., Effluent Gross -T.;--.f-Copper, total SAMPLE 50 (as Cu) MEASUREMENT 0104210;VPFrt. .t -"~ 1 N, -E~ffluent Gross A 3 K$S .__Iron, total

.......oo.. .f.(as Fe) MEASUREMENT Effluent Gross

..Lead. Total SAMPLE .50 (as Pb) MEAS5REMENT

"'A4 .. --, ,..". -. AoA"".. Y_'f:a -,v " ..NickSl. total SAMPLE ........ ......500 (as Ni) MEASUREMENT50 NAMEIfll.E J cendy wider penany of law mat mt document and at anenta were prepared wder rmy TELEPHONE DATE PRICIJ.AL EXECUTWE OFRCER d*ecbwl or i accrdance wdh a system designd to assure mat qualified pnpeuly ga2mer and evalute me Inmmaibi aubmitted eased an my inquiry o me pem o enom )rper Benjamin P. Youman who manage me systemn or mine pessa diirecly mapisbe for goameang me information.

me 815 406-3700 12J17/2012 infomonn subitted Is, to me beat of my knowledge and belief. tbue. a5 e, and onpiS. amn SIGNA rE 0 CIPLE Plant Manager aware Mot mere are signtant penalis fo ru Mlg Lawe Infomaon, ldig me posaiy ol EXECUTIE OFFICER OR AREA TPDONfiW= and for knowng vilak AUTHORIZED AGENT _,CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewatar during this month.2. Row existed 30 of 30 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/682012 PAGE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIlTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winlield Road Warrenville.

IL 60%55-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 IL0048313 PERMIT NUMBER I A01-0 I DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I DISCHARGE NUMBER I MONITORING PERIOD MMIDWYYYI MMIDDJYYYY DEMINERALIZER REGENERATE WASTE (001A)External Outfall* **NODISCHARGE E]" FROM'I 11/01/2012 TOI 11/30/2012 I I g I NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMrTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winlield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road IL0048313 PERMIT NUMBER B01-0 DISCHARGE NUMBER DMR Mailing ZIP CODE*MAJOR (SUBR 01) CS STP PLANT EFFLUENT (FORMER 0013)External Outfall M *' NO DISCHARGE r]61010 I MONITORING PERIOD MMIDDYYYY I I MMDD/YYYY I ..FROM-!11=01/2012 t Tol 11/3012012 I L I Byron. IL 61010 ATTN: Zoe Cox/ENV SPECFREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE P VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE_______ ANALYSIS ___SOD.027 0.35 2' 5.0 7.0 19 0 02/30 24 (20 Deg. C) MEASUREMENT 003io1o 194 30 ~ ' ot)>9J2 Effluent Gross "it- ... I *.pHSAMPLE ..... 7.13 ...7.61 12 0 02W3 GR pHMEASUREMENT 0040010 Cri"w .u-~~r rGA Effluent Gross 3 M ý :.ý,- -Sol.ttlsseddSAMPLE -c0.11 0.12 26 ...0<.8 2.4 19 0 02030 24 Solids, total suspended MEASUREMENT 0053010 .* h-Effluent Gross

'A .").'..- .-, ...'"Z.,:'" .,2.".Flow, in conduit or thru SAMPLE 0006 0007 3 0 01/01 CN treatment plant MEASUREMENT 5005010 .0- ..- r --.. 't...Effluent Gross- -_ _ .it a SAMPLE MEASUREMENT MEASUREMENT

__________

___SAMPLE MEASUREMENT

.____._._,__

_.-___..--.. ,r ;s. .M.4Z. ",:. "" gg,, .-~, -rt c: " .. ... .... ' Ns' .' a-. .n- .' .. ."- .'- .-... .. -.- _ .A-. ..It..--A....-.

NAMEnITLE I corfy under penalty of law maimt domimn and al atacumms w-re prepared under my TELEPHONE DATE PRINOPAL.

EXECUTIVE OFFICER irectio or supervison in acomdance with a system desgned to assure tht coalifidE perNoEnel properly gather and evake the Wnoation asubmitted.

Base an my inquuy at lte pemrso or pe'sons 815 406-3700 Benjamin P. Yournan who manage me system those persons directly responshe for gathering the inforation, he i 12/17/2012 information submitted s, to the best o my nowledge and true. accurf. and complete.

I am SlGNADIRE OFrORINCIPLE Plant Manager tware M there ae sianificant penes for suitiftngV fale Including the possiblity o EXECUTIVE OFFICER OR N EDA iwma .TEo fne and PUsNmneE for NTEnD AUTHORIZED AGENT CODE NUMBER MM/DDYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachmente here)1. Row existed through this outfall 28 of 30 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/A 12 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenviue, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 ATTN: ZOA CxIFNV SPFtC IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDWYYYY I I MMIDDWYYYY OUR Mailing ZIP CODE: MAJOR (SUOR 01) CS WWTP (FORMER ODIC)External Outfall***NO DISCHARGE EF ...61010 I FROMI 11/01/2012 J TOI! I!1 130/2012 I QUANTITY OR LOADING QUANTITY OR CONCENTRAllON NO. FREQUENCY SAMPLE PARAMETER EXOF TMPLE* VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Solids, total suspendedAME 1A4 2.5 19 0 02030 24 0053010 10 1.. " C. ,.Effluent Gross Ax. .....Chromium, hexavalent SAMPLE ... ..... ........(as Cr) MEASUREMENT 500 0103210 ToX .:..'Effluent Gross.Chromium, total 0M0PLE Soo (as Cr) ME ASREMENT_500

'Effluent Gross 42 AH, Copper. total 5AMPLE S (as Cu) MEASU RE__MENT_0104210 ,.. + ....- " Iron. tolal SAMPLE ,., Soo......(as Fe) MEASUREMENT 5_0 01045 10 ~-. '~1 ~ -~Effluent Gross Litz! _____~*, Lead, total S.A L So..... .... .,......5.0 (as Pb) MEASUREMENT

________ ____ __0105110 RO W .. j .* -., .,.Effluent Gross ,;,E A _____ -f -. ___Nickel, total SAMPLE ........(as NI)) MEASUREMENT, 5J 0106710 F. '""" ....'-' "" Effluent Gross Mx NAME/IL.E I candy under penarly d law dial ths document and al atladmvents ware prepared under my TELEPHONE DATE PIRIVNCIPAL EXECUTIVE OFICER a rctim at wuwwmi in acodarwe wit a system desoe to ssre thaT quaATd peEsD,1 3 properly gathe and evabite inse utformaa subMItted.

Based on rry kiquu d the persmn or persona 1 0-7011721 Benjamin P. Yournan w'ho mfsan fte s or fthse n diely respyonsbe Ior gatherinfa me inhanl ,,tel me12117/2012 inf suberitted Is. to the boest my knowledge and befiel, true. accurate.

and Coplt I am SIGNATURE OF PWCIPLE_Plant Manager aware it ame are aslpicart penaies for subtm0 false kiformitim k ft possiby of EXECU1IVE OFFICER OR AREA iwmoee lum and Hermem tIor WoY#g vicians. AUTHORIZED AGENT CODE NUMBER _MDDYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow existed through this outfal 111 of 30 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 16/2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (OMR)PERMITrEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 IL0048313 PERMIT NUMBER C01-0 DISCHARGE NUMBER DUR Mailing ZIP CODE: MAJOR (SUBR 01) CS WWTP (FORMER ODIC)External Outfali 61010 MONITORING PERIOD MMIDWYYYY MMIDOIYYY I ..... I FROMI 11101r2012 I ITOI A'L I 1 1iO12012 I* NO DISCHARGE F1 .---I lTOw II lPflul Iay I -- -NAMEnITLE PAINCIAL EXECUTMVE OFRCER Benjamin P. Youmian I ceiliy under penalty d ltw thal te dos men and all aatmntv s were prepared Under my directimor w petvim m accodance with a sysem desgned to assure tt quiatted pemainel properly gather and evalut me ftonnan submite. Baseed a my di te pesmn o perss who manage the system, atr tme persons ditly rsponsae far gatdwin Me Itwaf m i. thesumitted is. to te beso of my knowtedge and beief. true. accurate and compete I amn aware that them are mt penatst fr sutexdttg taine kitmiatm.

bedudf the possiaby al.te and bnpWrsnmef for aWmi valions.Plant Manager.. sm RUN=1 AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warranville.

IL 60555-5701 FACILITY Byron Nuclear Power Slation LOCATION 4450 North German Church Road Byron, IL 61010 OMR Mailing ZIP CODE: MAJOR (SUER 01) CS 61010 IL0048313 PERMIT NUMBER F01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDO/yyyy I MMIDDIVMY RADWASTE TREATMENT (FORMER 001D)External Outfal"* ' NO DISCHARGE-

" FROUI 11/01/2012 ITOt 11/30/2012 Il ll lIi I I I NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 WinFreld Road Warrenville, IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010]DUR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I IL0048313 IF E81-0 I PERMIT NUMBER DISCHARGE NUMBER 1 I g I .MONITORING PERIOD STORMWATER (FORMER 001LE)External Outfall*

• NO DISCHARGE FROMI 11/01/2012 TOI 11/30/2012 I I lATTN: Zoo CoxIENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Solids, total suspended SAMENT 005301 0U0ý --. 0 Effluent Gross, .-: .' , ..-__, '__. ' " ..Solids. total suspended SAME Other Treatment.

Process !3 .... "n"" iY Complete .........

....V......Chromium, hexavalent SAMPLE ..........

.(as Cr) MEASUREMENT

""" ' .1,.-' :7 -2 * " + ..' " 0103210 .2I" ""...Effluent Gross. " 7-'.. 4 ...., ...L Chromium, total SAMPLE ........ ....(as Cr) MEASUREMENT

_ __iii__010341 0 A-, L m ..-...'*.. .: Effluent Gross 1 1t !ý?Copper, total SAMPLE.........(as Cu) MEASUREMENT 0104210. ..-.. .... .Effluent Gross -W ,i , I Iron, total SAMP.....L

....(as Fe) MEASUREMENT

_ _ _ _*__ _ __ ___ __01045.10 -,.:r.. ... ... .._..Effluent Gross , Lead, total SAMPLE (as Pb) MEASUREMENT II______ ___0105110 Effluent Gross i w m l NAMEfTILE I ceriiy under penalty of law that ths document and ao aadiments were prepared uwider my TELEPHONE DATE PNCIPAL EXECUTIVE OFFICER dectn or supervsmn i accoMdance with a system designed to assure that qualifed personnel ipmperty gater and evalute Me sutnitteod Based on my kility of the po o person s Of ,.1, -1 7o Benjamin P. Youman who manage the system, or Utse pemms diectly spnsla for gatht ted i815I. 46e =370 12/17/2012 Inormation

.to the best o my Wowedge and belief, Int. acutate. and cWVotete.

Iam SIGNAPPE Dir RINCIPLE r Plant Manager aware tt Mrese are signifcant penaJtes to n fals itnnation, ioiflg the ps of EXECW'nVE OFFICER OR AREANUMBER MMDDYYYY T04E OR P Ime and nprseaonnnt for knowing U *vions. AUTHORIZED AGENT COD NUMBER _ _ /D____YY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. There was no discharge of processed steam generator chemical cleaning wastewater dudng the month.2. This discharge point was not used this month.EPA Form 3320-1 (Roe 01106) Previous editions may be used. 1/612012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEIADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 44,50 North German Church Road Byron. IL 61010 IL0048313 PERMIT NUMBER I E01-0 I S DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STORM WATER (FORMER 01 E)External Outfall 61010 MONITORING PERIOD MMIDO/YYYY I MMIDDIyyyy FROMI 11/01/2012 I TOI 11/30/2012 I*** NO DISCHARGE MX ...1 I II lI1 I.

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIT'EE NAME/ADDRESS NAME Exalon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUOR 01) CS 61010 I IL0048313 PERMIT NUMBER F -00 1-0 DISCHARGE NUMBER[ MONITORING PERIOD MMJD/YYI MMJD1YyYYY COOLING SYSTEM BLOWOOWN Extrnal Oufall FROM I 11/01/2012 ToI 11/30/2012

"'. NO DISCHARGE

[ ...m A Byron, IL 61010 ATTN: Zoe Coz/ENV SPEC _____ ____ ________ ___________________

____QUAN'TIrY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER EX OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Temperature, water dog. AMPLE 84.6 15 0 01.01 CN Fahrenheit MEASUREMENT 000t110 yen," -*. ~ ~ -Rq Effluent Gross : 'j L 'PH SAMPLE 8.44 8.69 12 0 01/07 GR MEASUREMENT 00400A10 .. 5. .9/Efluhent Gross ____ ____ ____ m r .i ý-Solids, total s- MEndedASEE 5.0 5.0 19 0 01/3E GR 00530 10 o .. ..., : .,..n... -, .. -. seq)M¥rL-Req Mar L .' .-Effluent Gross V_______ 'z" -" : .." ,_n..0i & Grease SAMPLE ........ <.....14 <1.4 19 0 "01/07 GR MEASUREMENT 0055610 ." Effluent Grass __________~h5 Chromium, total (as Ci) SAPL 0.0021 19 0 01/07 GR 0103410 ...............

...... .... ........Effluent Gross _., ., Copper, total (as Cu) SAMPLE ....... ...... .0.0040 19 0 01/07 GR Chrmim, otl (s r) MEASUREMENT

_-" ,*."'2 L ,. "- .Z " ' -.....* ' ______: ZincLtoal.........

.....00" " 0.010 19 0 01/07 GR Copertoal as u) MEASUREMENT, Effluent Grs ,w. .. -,. .. ...NPmE/TITLE I ceruty under pentaly o law a Ots documnt and al an w pr under ly TELEPHONE DATE PRINCIPAL E)ECUTIVE OFFICER dumreon or supen~on in acýoac wih a s~ey desý to assure to quafi"ed pereor, "Dr prmperly gade and evauz the informador autmiled.

Based an my ahelUse pesm or perSo n14-7 Benjamin P. Youman who manage the syatam, or rmee persons diecly esponsbe for the itfonmalion.

the- 815 406-3700 12J17/2012 nloimaon suwmitd is, to the beat oo my " wde and bet.ie tru. accurate.

and canpietI am SIGNA R F 0 ____Plant Manager aware Met ther are sinc pen1a es tor R v iabn intorrnaon.

ixuding the posamiuy d EQ OCER OR AREANUMBER MDYYYY oRMNI Ifire knpnandb isme2 l Whknowaig AUTHORIZED AGENT cODE NUMBER _ _ _ _ _ _ _ _ _ _COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Referemnce all attachmenta here)1. Monitoring data for outtall 001-0 is included on attachment EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/8=2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMrrrEE NAMEIADDRESS NAME Exeton Generation Co., LLC ADDRESS 4300 Winfield Road Warrenvile.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, L 61010 I DUR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 I IL004N313 I I 001-0 I PERMIT' NUMBER I I DISCHARGE NUMBEA 1....... .... ... DI C A G NU BE .. .... .... .MONrIORING PERIOD UM/IDIYVYYI MMIDD/Yyyy COOLING SYSTEM SLOWDOWN External Outaidl** NO DISCHARGE r-- "*" FROM I 11101/2012

! TOI 11/30/2012 I QUANTITY OR LOADING QUANTITY OR CONCENTRATION

__ .FREQUENCY ARAMETERO OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX AOSF TYPE Oxidants, total residual SAME .... ..0.05 19 0 01/07 GR totl rs~dal MEASUREMENT___________

____________

3404410 ... '"-- ,. ..- "- -., Effluent Gross -1. ._' .: ..., ---L , .: :.. ,, -,R Priority pollutants total effluent SAMPLE .........MEASUREMENT Soo.50 5000810 'aww*.Effluent Gross Y. M ..Flow, in conduit or thru SAMPLE ......treatment plant MEASUREMENT 1874 2928 3 0 01101 CN 500501 in 4.,.Chlorine.

total residual SAMPL.E .....MEASUREMENT SIX0 5006010 1 u' n ,-. -.. .- .... .." -........Effluent Gross -Z -.,,_ ,_-_" -r-;Hydrazine SAMPLE........

......MEASUREMENT 500 8131310 :.. ..-.. * " .7..911- -.,,.,.- "'Effluent Gross "'A- P___ _ ._ , " SAMPLE MEASUREMENT 7_ ..... ... ! ." NAMIfTL ~~Wwm~wtegm,.'AMPL____E I[AUiF./1111 I under Parkell 01 law 80 domainen and all atlamnmets wev repirepad wunix PRINCIPAL EXECUrTIVE OFFICER dacaion or supervi In with a system designed to assure dim quatfied personnel TELEONE DATE BenjaminrP.

Youman erlygather and OvakMa the Inoimnian subhl1tLd.

BasOed aniny equnyat dethpeserinm peos'- 37 Y n o manage de system, tose persns dirocty respons r to gat-emnn te lonnan. the 4 12/17/2012 PlantaManager WOtatian Subansled IS, to eua banad rmy knowledgeand bel'. ue. arai'e and congple. lam Plan Maager war thimter are signitiant Penalte lot submiting taise bidannation, intdiidg the possibulyt NUBE MMDVY T f1ne and intrnsionment for knowing vioatatas AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1162012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIlTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road IL0048313 I PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD S MMIDD/YYY I I MMIDnIYVYY OMR Mailing ZIP CODE*MAJOR (SUBR 01) CS STORMWATER RUNOFF BASIN External Outfall*' NO DISCHARGE r 61010 I I I ....FROM i 11/01/2012 I T"o 11/301,012 I Byron. IL 61010 ATTN: Zoe Cox/ENV SPECFREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS Solids, Total Suspended SAMLEM 00530 10 ..... " "i'Effluent Gross .110__ , .0_- Solids, Total Suspended SAMPLE 0053080 pjJg ; " n Other Treatment, Process ."- ::' " -A : ." '. .,....Chromium, hexavalent SAMPLE (as Cr) MEASUREMENT 01032 1 0 A,. .... -.. .Q .-, Effluent Gross 12S Chromium, total SAMPLE (as Cr) MEASUREMENT 0103410 777" y ...- '" .U " : -O.p... .. .ft"Q Effluent Gross vt~lj _____.- ___Copper, total AMPLE.(as Cu) MEASUREMENT 0104210 ...R IR'lT ,.* :. *"- .-Aj -.,04- x: ..." Effluent Gross C___ .j ~ a Iron, total SAMPLE .....(as Fe) ME.ASUJREMENT 0104510 -u *RWv -Effluent Gross I _

Pi-, ,, ,._, ,A.Lead, total SAMPLE ......(as Pb) MEASUREMENT 0105110 ~GA Effluent Gross _"______,__

'NAMETITmLE I certify under penalty d law tat Ud s do=wet and at alladunemnta we prepad under my TELEPHONE DATE PRINCIPAL EXECUTIVE OFFICER direl0w or supenisolin arcordance with a system designed to assure qualified personnel TLPOEDE prpet Gather and evalute Me infomaon asubretted.

Based a my inquiry of the peaon or persons 815 406-3700 Benjamin P. Youman who lmanage the systern. or Vos persons resp fo gaterng the lnloma12/17t2012 Information subTWitte s to the best al my bmwledgle and balie. true, accrate, and cowtpiete l am SIGNA=TIJ F CPLE 121-21 Plant Manager aware that there we wignc penalties tor aoranling fale intfomation, chding the posabily a EXEU OR A NEA TVo OR PRM_ ..ne and kpr__nMent far Mowing vW131ons.

AUThORIZED AGENT CODE NUMBER MM1DDr/YYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Referance all attachments hee)1. No Turbine Buiding rm and Oil Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection.

Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous edilions may be used. 1/612 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road WaenviTle, IIN 60555-5701 FACILUTY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 OUR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 I IL0048313 I PERMIT NUMBER 002-0 DISCHARGE NUMBER MONITORING PERIOD MM/DYYYY I I MMIOOYNY STORMWATER RUNOFF BASIN External Outfall* *NO DISCHARGE M- ...I.I TOI I ... ..I FROM I 11/01/2012 ITOt 11/30/2012 I I li -v-l I I j.I I I I I.i I ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 November 2012 Page 1 of 3 MONITORING DATA: WBD C WBD Flow Rock River DATE Temperature mgd Flow deg F cfs 11/01/2012 78.6 18.85 2280 11/02/2012 78.6 17.29 2260 11/03/2012 78.0 21.35 2270 11/04/2012 78.0 13.75 2310 11/05/2012 75.2 21.48 2200 11/06/2012 75.3 18.99 2190 11/07/2012 75.3 16.59 2170 11/08/2012 78.0 19.01 2220 11/09/2012 76.1 16.86 2170 11/10/2012 82.8 21.39 2190 11/11/2012 83.1 17.06 2290 11/12/2012 83.1 13.66 2440 11/13/2012 74.0 18.21 2270 11/14/2012 74.0 17.48 2270 11/15/2012 78.8 20.53 2310 11/16/2012 78.8 17.97 2300 11/17/2012 75.4 25.52 2250 11/18/2012 78.5 19.54 2240 11/19/2012 76.0 13.52 2210 11/20/2012 82.8 21.90 2220 11/21/2012 77.8 16.88 2210 11/22/2012 84.6 18.34 2310 11/23/2012 83.9 19.55 2240 11/24/2012 72.2 29.28 2100 11/25/2012 73.8 16.12 2080 11/26/2012 75.8 14.28 2090 11/27/2012 72.3 19.84 2080 11/28/2012 74.4 18.57 2100 11/29/2012 74.2 19.11 2060 11/30/2012 78.4 19.36 2070 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 ReportsNovember\November 2012 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 November 2012 Page 2 of 3 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of November 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 30 of 30 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 5.5 mg/L on 11/12/2012.

The CWBD TSS value was 5.0 mg/L on 11/12/2012.

5. Rock River flow was <2400 cfs starting on November 5, 2012 therefore daily temperature calculations were required during this time period.(Special Condition 12). Per Special Condition 12, in the event the Rock River flow is <2,400 cfs, daily calculations will be undertaken to demonstrate compliance with the water quality standard.

The calculations are based on hourly measurements, averaged over a 24-hour calendar day for Rock River flow, main Rock River temperature, CW Blowdown flow, and CW Blowdown temperature values. Results of the calculations shall be reported in the DMR on a monthly basis. Calculation results are in the table on the following page.6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in November 2012. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\November\November 2012 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit 1L0048313 November 2012 Page 3 of 3 Date Average Average Average Average Calculated Water Quality Rock CW M/U CW CW Temperature Standard River Temperature Blowdown Blowdown at edge of Temperature Flow (F) Flow Temperature mixing zone (F)(cfs) (gpm) (F) (F)11/05/12 2330 45 13239 71 45.6 90 11/06/12 2328 44 13075 72 44.9 90 11/07/12 2300 45 13129 74 45.6 90 11/08/12 2250 46 12379 75 47.0 90 11/09/12 2044 46 12133 78 47.3 90 11/10/12 2055 50 12171 84 50.9 90 11/11/12 2153 52 12158 82 53.1 90 11/12/12 2300 47 12246 70 48.1 90 11/13/12 2138 44 12738 69 44.8 90 11/14/12 2205 44 13600 73 45.3 90 11/15/12 2294 44 13475 74 45.1 90 11/16/12 2285 44 13613 75 44.9 90 11/17/12 2240 43 13692 76 43.8 90 11/18/12 2219 43 13713 78 43.8 90 11/19/12 2190 45 13688 78 45.9 90 11/20/12 2205 47 13663 80 48.2 90 11/21/12 2205 48 13600 78 48.6 90 11/22/12 2318 48 13417 83 48.8 90 11/23/12 2243 45 13538 69 45.4 90 11/24/12 2101 41 13638 71 42.4 90 11/25/12 2076 41 13646 74 42.8 90 11/26/12 2093 40 13721 72 41.4 90 11/27/12 2030 38 13592 69 39.1 90 11/28/12 1973 38 13683 73 39.1 90 11/29/12 1963 38 13571 74 39.9 90 11/30/12 2060 41 13596 75 42.2 90 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\November\November 2012 ATTACHO1.doc Exelon.Exelon Generation Company, LLC www.exeloncoTp.com NudeaT Byron Station 445o North German Church Road Byron, iL 61010-9794 January 17, 2013 LTR: BYRON 2013-0010 File: 2.09.0411 1.10.0101 Illinois Environmental Protection Agency Water Pollution Control Compliance Assurance Section #19 1021 North Grand Avenue East P.O. Box 19276 Springfield, IL 62794-9276

Subject:

Byron Station Monthly Discharge Monitoring Report In accordance with National Pollutant Discharge Elimination System (NPDES) Permit Number 1L0048313, issued January 24, 2011, we are submitting the Discharge Monitoring Report for Byron Station, Units 1 and 2. This report covers the period of December 1, 2012 through December 31, 2012.If there are any questions regarding this report, please contact Ms. Zoe Cox, Environmental/Radwaste Supervisor, at (815) 406-3035.Respectfully, Benjamin P. VoumaY 7 Plant Manager Byron Nuclear Generating Station BPY/ZC/eh Attachments bcc: 4-Geutd -Environmental

-Cantera (electronic)

Z. Cox -Chemistry

-Byron RM-AA-101-1008-F-03-Revision 0-Exelon Generation,, Page 1 of I SPECIAL HANDLING TARGET BEST AVAILABLE COPY ............................................ (Next j 2 pages)CHART/PHOTO(S)/TRACES REMOVED ............. (Next pages)OVERSIZED PAGE/DRAWINGREMOVED

............ (Next pages)Record page is larger than 11 x 17 inches.O TH ER ................................................................................... (Next pages)EXPLANATION:

To Be Completed By Preparer: Document Number: List of pages, documents or drawings removed:** SEE SITE RECORDS MANAGEMENT FOR HARDCOPY LOCATION **

NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (OUR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road OMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 EI D101IN13 __A01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDDIYYYY

[_ MMDDJYYY DEMINERALIZER REGENERATE WASTE (O01A)Extenmal Outfall* *NO DISCHARGE

...FROMI 12101/2012 iTOI 12131/2012 I i I Byron. IL 61010 ATTN: Zoe Cox/ENV SPEC ______________

___________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF 8ML VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids. Total Suspended SMPLE 1.1 1.2 19 0 01M30 08 (as Cr)MEASUREMENT Effluent Gross..........

Chromium, total SAMPLE .. .. .. ... -.(as Cr) MEASUREMENT So'Effuent Gross2 Copper, total SAMPLE ...0104210 ".' 'A'.Iron, total SAMPLE (as Fe) MEASUREMENT Soo Effluent G PLE Lead. Totl. SAMPLE t........

...n. t....(as Pb) MEASUREMENT 500 01051 1 0 777 =,'."" '; ."... -" --" Nickel, total SAMPLE ..... ...., .,.,00 (as Ni) MEASUREMENT Soo!Effluent06 1Gross0

mw -=02="

.-A ,:. ...4': Nicite.......

toalSAPE ...NkAETnTTLE I coesiy under penaly of law dMi dms dcummet and an attactmms ware ptepamd n TELEPHONE DATE PR"INPAL EXECUTIVE OFFICER imect or saupemismon In accoudance wair a system designed to assure md quaaed peabronel BnanPty games and evakte Me subitted.

Based on fm mqway d de perrsso 406-370 Benjamin P. Youman who manage me systman or ies pemis drecay responsiue for gafthenng ume 01112013 idonfan sutnfte is. to me best o my tu,,edge and bene, tie, and a coW0in. am 8GITU RE(OF PRINCIPLE Plant Manager swam Owat the1e are penaltres fo subln bonnal. bicutth de possb* of EXECUTIVE OFFICER OR NMfA iv mo o an a and krofb nai fo k viakna AUTHORIZED AGENT CODE NUMBER __IDDI__ _ _COMMENITS AND EXPLANATION OF ANY VIOLATIONS (ReFenmce al attachments hem)1. There was no discharge of processed steam generator chemical cleaning wastewater during this month.2. Flow edsted 31 of 31 days during this monh.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/62012 PAGE1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEJADDRESS NAME Exalon Generation Co.. ILLC ADDRESS 4300 Winfield Road Warrenville.

L 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 OMR Mailing ZIP CODE.MAJOR (SUBR 01) CS 61010 iL0048313 PERMIT NUMBER A01-0 DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY

__ I MMIDDI"YYY DEMINERAUZER REGENERATE WASTE (O01A)External Outfall* *

• NO DISCHARGE FROM II 1201/2012 To[12/3112012 Il I I NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEIADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warranvifle, L 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byronm IL 61010 A fýf.=Klk c-7r ' IL0048313 PERMIT NUMBER iB01-DISCHARGE NUMBER DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS STP PLANT EFFLUENT (FORMER 0015)External Outfall' NO DISCHARGE 61010 I ~ MONITORING PERIOD I MM1Daq-fYY I TO[MM/DDIYYYY I FROMI 12/01/2012 12/31/2012 Il i QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE BOD, 5-Day SAMPLE0.2 4.0 40 19 0 02/30 24 (20 Deg. C) MEASUREMENT 0024.12_Effuen Gros E1UM M1II ýý7 an' -ýe 'pHAMPLE 724 7.46 12 0 02/30 GR pH MEASUREMENT Solids, total suspended SAMPLE 010 02_12922 MEASUREMENT 0.00126--19201 0 00 4 Flow. in conduit or tiru SAMPLE lag .treatment plant MEASUREMENT 0_004 0.00__ 3 0 _010___5005010 ý' Ma~v 'PiG~~.. fjqIoRMin.

~-~r Effluent Gross .:x -. .SAMPLE MEASUREMENT SAMPL.E MEASUREMENT

.__.._____._"_____._-,_

....-,. ...... ;.7 .*SAMPLE MEASUREMENT NAMEITlTLE I cei* urtnd penafy ,U tof taw QW documn Sfl am attadhnta e iaeda, 'erV TELEPHONE DATE PRINCIPAL EXECU11VE OFIFICER dmj w supenan in a :gance with a syton deswgn to assure toas quaffia penamTPel PmPtwoandevatme clyl. Based aon Iy gahurod me pedm or per"* , Benjamin P. Youman wto "aa Of s te sPOM &'O' for galhef ' w iCdmokw% the -01/17/2013 Wfnabmn sWjflf i to d to beso f my Wodep and bWe .tue,. a, aopir, la SIGNAadnE OFr IICIPLE .I_____Plant Manager aware mad mare am sl*gfncam penawds t0f suba&fg faWs W=ta .bkWdAtg ma P9ua9t of EXECUTIVE OFFICER OR AsFJ Wa OR ,mPOW= foe and k inpsnnnt for knawin0 vailatmins.

AUTHORIZED AGENT CODE NUMBER MM/DD/YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. Flow eidstad through this outfall 28 of 31 days during this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 PAGE 1*0 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60655-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE.MAJOR (SUOR 01) CS 61010 IL0048313 PERMIT NUMBER C01-8 DISCHARGE NUMBER MONITORING PERIOD MM-/DYYY I MM.OYYYY Exenal Ouftfl* N ISHRE E .l I FROM I 12101/2012 I ITO 12031/2012 I! i Byron, IL 61010 ATTN4: Zoe Cox1ENV SPEC_____

_________

_____________________________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER E____OF PARAMETER

_ _ _ VALUE VALUE UNITS VALUE VALUE VALUE UNITS 0X 24 TYPE Sld.ttlsseddSAMPLE

.........5.8 6.2 19 0 02r'J0 24 So~s, ota supened MEASUREMENT 0053010Al Effluent Gross an.- _ --Chromium hexavalent SAMPLE Soo (as Cr) MEASUREMENTEfmflunt Gross -, Chromnu. total SAMPLE ....(as cr) MEASUREMENT 010341 ýF-4 --copper. towa SAMPLE .... 0 (as Cu) MEASUREMENT 5 0104510 Effluent Gross ail&010 51 ... ..~ A ... ...total APi. ..(as Pe) MEASUREMENT Effluent.

Gross LNckAel total SAoMiPLEc...... "W'""'DATE (as Nb) MEASUREMENT Pln aae wr itmr resgismpni o umn lae kulmuta. uma th 5iEEUTV CRO (a apin MEASUAREOMEDNAENT CO 010671 .'. .-,,-- ...- ...........Effhluent Grs ...... ..a-n .sL:ltm ..."m ".; ' -NAMEF.E ACeNDyuPLNpeAIyO law AV aO (Rectecumaene all attachmntos werepd ) udet a TELEPHONE DATE P1U.Tmwa ExndcuhE OFaRCER orcesnsed stam genea assureng thi maodnt 2.pFly ease tevhrughe m s. ed ti outfallhe1person or 21, 815 du4ine7o BenPamin P. You(Ran 011o ma8Pae te systeMt on mae peMuns dreCtd .spna* ko 0aet te infonnam fe 01/17/2013 Inorrnadon subnmtted IL. to the besooJ dy rri mftd and befiel, true. &=Mne. and *ompleteI arn 81GNA'IRJRE OF FMCIPLE Plant Manager aware doa there are sJ~mman perwatis for subyqMmiss Waratsikomdn, Wb th #w poL~ d XCUIEr OFACER OR AREANUERMfDYY UoR51M m -mu f re and hofteonmet for bmin Adta AUTHORIZED AGENT ICOIDE NME MDN COMMENTS AND EXPLANTION OF ANY VIOLATIONS (Raefenrce all attacheunnts here)1. There was no discharge of processe steam geneaetor chemical cleaning wastewater dufiN this month.2. Rlow through this outfall 12 of 31 days during the month, EPA Form 3320-1 (Rev 01M0) Previous editions may be used. 1/6/212 PAGE 11 PERMITTEE NAME/ADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenvllle, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)1L0048313

-C01-0O PERMIT NUMBER DISCHARGE NUMBER MONITORING PERIOD MMIDD/YYYY M umiDWYY DMR Mailing ZIP CODE.MAJOR (SUDR 01) CS WWTP (FORMER 001C)External Outfall... NO DISCHARGE 61010 FROMI 12f01/2012 TOE 12/31/2012

-l .11l !Byron. L 61010 ATTN: Zoe Cox/1ENV SPEC _ _FREQUENCY QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF AML VALUE VALUE UNITS VALUE VALUE VALUE UNIT EX ANALYOS TYPE Zinc. total SAMPLE ........ .... ..... 500 (as Zn) MEASUREMENT Flow. in conduit or thin SAMPLE 00500730 0/1C treatment plant MEASUREMENT 50050 10 ,N&4 .A Effluent Gro.ss i .....SAMPLE MEASUREMENT A:r, Ir L... ....-r --SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT MAM~nLt.E I comy I w ier penally a law that ON documen and afl aulltac ens were prpared wnder my TELEPHONE DATE PRNcIPaAL ENECUE OFRCER a.econ oa supesiwon In with a sstem designd to assure Ins quamuied pemonnel pmpeily gather and evaelut e Ibomaan ationsubated.

Based on my fiqubV ol the peson or pers" 815 406-37W Benjamin P. Youman who manags me system or Wans persons direcly responsie ko gad.ie0g Ue InlonWal the 01117/2013 nfmoamtion subnitted Is to the best o my Ikowledge and beaef, trnue accurate, and complete.

sin a 1GNA1 REOFOFAC ICPLE L E Plant Manager aware that there are signifirant pties for subn Wlee innnatlm.

idug the d EXECUTIVE OFFICER OR ARE.D TVM ON pRV'W fine and kpembonient for knowwn g AUTHORitED AGENT CODE N R COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hame)EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/612012 PAGE 2 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAMEIADDRESS NAME Exelon Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mail'ng ZIP CODE.MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER D01-0 DISCHARGE NUMBER MONITORING PERIOD MmDOJYtY I MUJDW/YYYY RADWASTE TREATMENT (FORMER 001D)Externl Outfall*'*NODISCHARGE I .. .. .I FROM!I 12101/2012 I 7ot 1"2F31/2012 I FROMI-I I Byron, IL 61010 ATTN: Zoo Cox/ENV SPEC _ _ _ _ _ _ __ _ _ _QUANTITY OR LOADING QUANTITY OR CONCENTRATION

.FREQUENCY SAPLE PARAMETER OXFYP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Solids. total suspended EAURMLEN3 5 19 0 0230 C 00530 10 V- *Effluent Gross Flow. in conduit or thru SAMPLE 0-=2 0.022* 0 01/01 CN treatment plant MEASUREMENT 5005010 Effluent Gross-iv -.*... ..7'.. ~ ~ ~ ~ *~~SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLENAMERM I cewy wvdar ipanay of law 00 dils domman an a. anadners wae paae wia ,nri TELEPHONE DATEEXECUlME OFfRr= dmcum or &Wve#M= Mn wfire a dfsi~nd to assure 0a0 %WaNW perm40nngame and mavaile die Warriai uteid. Based an mry quizy of the paisan s 7815 7 Benjamin P. Youman who manag de swatm. o mdie persons directly responsUae lr gadw0g me kdamma. the 0 01/17/2013 mfonmatn sutimted Is. to me best of my Irmwledge and betel. true. maarate. and cMMMa. I am SI RE OF __N-'_PLE Plant Manager aware dial dmer are sil0aicar penates for wAumta falsse tdoarnani.

icdig fe ol EXECUTIVE OFCER OR NUMBER MWDD/YYYY oa and Impds~ne f AUTHORIZED AGENT CODE COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. Flow existed through this outfall 4 of 31 days during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. I/6012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMIITEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Warwville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 NoMtt German Church Road Byron, IL 61010 AI'rlM. 7nn DMR Maling ZIP CODE'MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER E01-0 DISCHARGE NUMBER E MONITORING PERIOD MMIDD/YYYY j I MMIDDJYYYY STORMWATER (FORMER 001E)External Outfall* 6 NO DISCHARGE M ...FROMI 12101/2012 12/31/'2012 QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OF VALVAL UALUE UNITS VALUE VALUE VALUE UNITS E ANALYSIS TPE Solids .-tota SupndMAURMLEN 500 Solids. total suspended APLE..161 182 19 0 01/07 GR Chrmium hexavalent SAMPLE ..*.. ... .. 0 0103410 MEASUREMENT Copide, total SAMPLE ..... ....... 0107 (as Cu) MEASUREMENT 01034210 ."'. ..'.'"" -' 4:. ,., Efflu~enlmt ProeosIts Crome, total SAMPLE ...........

O (as CF) MEASUREMENT Soo 0 1 0 3 2 1 0 .., .! <. .... .....'- ..' .; , -.- "..,- 4 4 -* -.... ." --..'- '.E fflu e n t G ro s s .- ; -.. .. ._ .i ---------- -Chromiu, total SAMPLE.............

(9s CF) MEASUREMENT 500 Lead, total SAMPLE...........

......(as Pb) MEASUREMENT_500 NAE1nE i cartIIy wtde penaity ,d lw Sta ti nw and aD Itchmest were iragard under inTEEPON DATE____________________ aupendeamin in accordance wair a syte designed to assure that quashed pericnna ___ _____________

proeitygathr aneviahue te horniasubei aotad. 8ased onmy Inquhy te person orm pera-- 1540-30 Benami P.Youan who manage the system. or these pei~sat dlrec~ reposlema for piherbg the inonabon.

the017/03 Belma MOnlabOI sum~ s .. me bes ,, myI ~ddg tast in, anti oonme.m em SIGNA RE OF/

0/721 Plant..M~anager aware tha there are slgritean penslas for auailn false bionmtaio, bldud~ng the poassbuty d EXECUTIVE O1ICER OR NUBERMIDIYY-.m , e and mrnpiismarei ho kncow~ng sioIORZD GEa OE UMERM/DsY.

COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments hem)1. There was no discharge os processed steam generator chemical cleaning wstewater during the month.2. Ftow etialed through this oull 0of 31 days dunng the month.3. There was no flow from this outlall this month however FRe Protection drain waler was discharged to this outfall this month which rsauires TSS samplinaj.

EPA Faont 3320-1 (Rev 01/06) Previous editions may be used. 1/6/2012 _PAGE 1I NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITTEE NAME/ADDRESS NAME Exalon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 A1TT'-

Acc:r'1 DMR Mailing ZIP CODEt MAJOR (SUBR 01) CS 61010 RIN0048313 PERMIT NUMBER If E01-0 DISCHARGE NUMBER 1 MONITORING PERIOD MM/DW1YYYY j I MMIDDIYYYY STORMWATER (FORMER 001 E)External Ouffall* "*NODISCHARGE J 7 ..FROMI 12/01/2012 TOI 12/31/2012 il *QUANTITY OR LOADING' QUANTITY OR CONCENTRATION NO. F SAMPLE PARAMETER EX OF TP VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS TYPE Nickel, total SAMPLE .500 (as Ni) MEASUREMENT" Effluent-Gross Aic, total SAMPLE ...... ...... SI-as Zn) M EAS U R EM ENT _ _ _ ...--, -F1ow, in conduit or thi SAMPLE Soo treatmn plant MEASUREMENTI SAMdPLE ME.ASUREMENT" SAMIIPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT iMEirn.uE I cead under penalty al tar thas thaus dfcument an alt taces wem prepared tinderY TELEPHONE DATEEE WE dormn or i awdin ance with a system desrgned to assum dos cpqauhed pereonet propeity gaowe and eva~lue the mfomatuon sassaa Based an my tupy of fth pe=o or perona 1 4630 Benjamin P. Youmnan vanage the system a tfse msona y esptmsWae for gamem the adon. the --01117/2013 intoustiom subn*,M i. to the best d my ,uzusedge and nue. acuse, and cmpe. I am flNATUR# nCIPLE Plant Manager awam dal there are s0ficant penaltIes fortalg lalse nldoma.b kcduding fth Pefity Of EXECUTIVE OFFICER OR AREA NUMBER MMIDDJYYYY Au.OR AWFlD The and porsblnmme for lonM,,g violatwns.

AUTHORIZED AGENT CODE NUMBE M_/DD/_YY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Refererne all etachments hea)1. No Closed Cooling System Drain Water was discharged this month.2. No Service Water System drain water was discharged fths month.3. No Turbine Building Fire and Oil Sump or Generic Non-Chemical Cleaning wastewater was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 16/2012 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)PERMITrEE NAME/ADDRESS NAME Exalon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron, IL 61010[ IL0048313 I I PERMIT NUMBER ao-1c DISCHARGE NUMBER MONITORING PERIOD MMIDD1YYYY I I MMIDD/YV DMR Mailing ZIP CODE:- 61010 MAJOR (SUBR 01) CS COOLING SYSTEM SLOWDOWN External Outfall***NODISCHARGE E *i I I1 FROM I 12/01/2012 I TO I 12J3112012 l lATTN: Zoe CoxffENV SPEC ____________________________________

_____QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF SAMPLE VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX A F TYPE ANALYSIS Temperature, water dog. SAMPLE .90.5 15 0 01101 CN Fahrenheit MEASUREMENT Effluent Gross 61,'D = = " IýPH 8AMPLE -- 8.53 8.71 12 0 01/07 GR pH MEASUREMENT 0040 10 ~ ~ ~ 'Effluent Gross I' 90 i-06ý M AN RAj..... ...- SAMPLE 4.2 4.2 19 0 01/30 GR Solds toalsusened MEASUREMENT 00530 10L" Effluent Gross ___OiASURESAMPLE

... ...1.4 <1.4 19 0 01/07 GR Oil & ~~ MEASUREMENT

__________

Effluent Gross .Chromium.

total (as Cr) SAMPLE -<..0021 19 0 0107 OR M E A S UR EM E N T. .. ..0 21 001 / 7R 01034106 Effluent Gross Co~pper. total (as Cu) SAMPLE ...........

........07 O MEASUREMNT0.038 19 0 01/07 GR 0104210 :"!.. ..-" -D- .Effluent Gross Zinc. total (as Zn) SAMPE 4.005 0.014 19 0 01/07 GR!Zin. ttal(asZn)MEASUREMENT, Effluent Gross r. -...A NAKEInTLE I ceitiy under penalty l law tht Os document and alt atachrnents were prepared under nm TELEPiONE DATE PfUML EXECUeVE OFRCER drecon or mkoemisin acwdance with a system designod to assure tha quaited personnel prpiygather and evalulo the intomtnaton sutnaltad.

Based an mry kqutLy at the person of Persons854630 Benjamin P. Youman mho Manage the system. or thoee pewsons directly mpWse tor gath the uifonnaMn the 01/17/2013 fornma=in submined Is. to the best .d m knonedge end ballet. tue. amurate. and omite. I aam SI REOFiiNCIPLE Plant Manager aware that Mere am swripcaN penaltmies forubAing false Ieonnaimn, incdting te fpass" of EXECUTIVE OCFICER OR AREA TWEmappamiml fine and nprsbnenfng viecatlow AUTHORIZED AGENT nnNUMBER MMaDDaYYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Rahefmnce all attachments hem)1. Monitoring data for outfall 001-0 is included on attachmenL EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 1/8/2012 PAGE 1 0 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DMR)IL0048313 001-0 PERMIT NUMB3ER DISCHARGE NUMBER 0 PERM7TrEE NAMEJADDRESS NAME Exaton Generation Co.. LLC ADDRESS 4300 Winfield Road Warrenville, IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road Byron. IL 61010 AT"rNI 7n MONITORING PERIOD MMUIDIYYVY I UMADOIYYYY DMR Mailing ZIP CODE: 6101(MAJOR (SUBR 01) CS COOLING SYSTEM BLOWDOWN Extenal Outall**INO DISCHARGE EJ"'0 FROM FROM I 100112012 I TOI IPi 1A)- -QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX OF TYPE>< ANALYSIS Oxidants.

total residual SAMPLE ...... 0.04 19 0 01107 GR MEASUREMENT 34044 10 ..'- ...Effluent Gross Fl f Pnority pollutants total effluent SAMPLE Soo MEASUREMENT 0 60006810 V.., ~Effluent Gross Flow, in conduit or thru SAMPLE "" treatment plant MEASUREMENT 1965 25.55 3 .0 01/01 CN 5005010 Effluent Gross Chlorie. ta residual MEASUREMENT50 6006010

"" ":-"' , ."; ,, ....Effluent Gross Hydrazine PLE 500 MEASUREMENT 50 8131310 7.... .... Qs -Z " .." Effluent Gross SAMPLE-'MEASREMENT SAMPLE MEASUREMENT PRINCIPAL EXECUT1VE OFRCOM Ifb or suoesmtn In accmance wb a syster deineo to asure am qga~llw IPOEDT-W ypeaglh nd evalum the klm,.mmurus-clL Baudanaqmqlft oft M- r, mper-m I-M 815 406-37001 Benjamin P. Youmnan Ww manap the system, of mos persons &acty mspw-,ft for 9whef fte um .meNPE0)YRNIL 01/17/2013 Plant Managler Mxmnadm umteo Is to the best of mvy bwwmcp anda bdef trim. acaraWe and emO GU1 lIn 81- R ,=RIC sao~g ware 20a "Mo are sofficant mowns for Wubv false wnmoabm hdlut the pos of EXCTIE FICER OR AREA NUBRMM/DD/YYYY 7,. fins and ImDW-M=O fOr M..M AUTHORIZE AGENT COMMENTrS AND EXLANAT1ON OF ANY VIOLATIONS (Reftmice al attedmnems h"r)IEPA Form 3320-1 (Rev 01106) Previous editions may be used. 116=212 PAGE 2 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DUR)*1 PERMITTEE NAME/ADDRESS NAME Exelon Generation Co., LLC ADDRESS 4300 Winfield Road Wanenville.

IL 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road OUR Mieling ZIP CODE: MAJOR (SUDR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 I DISCHARGE NUMBER I MONITORING PERIOD MMDD'IYYYY I I MMIDDYYYYI STORMWATER RUNOFF BASIN Exern Outfai~NO DISCHARGE I I I FROM I 1201/2012 I TOI 12031/2012 I Byron. L 61010 ATTN: Zoe Cox/ENV SPEC______________

__________

__________

QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY PARAMETER OF VALUE VALUE UNITS VALUE VALUE VALUE UNITS EX ANALYSIS TYPE Solids. Total Suspended SASMPEN .....00A3010 E.... ...Effluent Gross b Z N a ;Solids, Total Suspended MEASUREMENT 00538Tr0ie Pwo.Compirlete Chromium.

hexavalent SAMPLE (as Cr) MEASUREMENT 0103210 %,l ' " Chromium, total SAMPLE (as Cr) MEASUREMENT 010341 0 .....' : ..., -' ' .. ... .. ..'- .' W-. ". "....Effluent Gross Copper. total SAMPLE *. ,*(as Cu) MEASUREMENT 0104210 " ' 1 Effluent Gross (as Fe) MEASUREMENT Effluent Gross Lead, total SAMPLE ....... ...(as Pb) MEASUREMENT 01051 10 -' ':i]: " ' '".. .....Effluent Gross ;..

' ....'NAMEII1TLE I certiy under penafty o law that thi docmemu and aff aachimems were prepared under my TELEPHONE DATE PRINCPAL EXECUTIVE OFI=CER irection or supenmsln in accrdance with a aysen to assure hat mared pesonnel propeu gather and evalute the information submitted Based an my trly of the person or perons .815 406-3700 Benjamin P. Youman who manage the system or those persons drdW respae sbe for gathering the Weomatin, the 01/17/2013 Infomation submitted Is to te best of My WONeg and bettef. rue,. and ciplete. Iam 9LE Plant Manager aware at them are significant penalts for submittling lalsme inforama, Icluding the possbrty ol EXECUTIVE'OFFICER OR AREA ssW O am Oni and imprislantmenl for Incetng vxiatlanMERa.OIYY

________ 1e and_________________________

AUTHORIZED AGENT CODE NUMBER _MDDY __Y COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. No Turbine Building Fire and Ol Sump or Generic Non-Chemical Metal Cleaning Wastewater was discharged this month.2. No Fire Protection, Service Water or Closed Cooling System Drain Water was discharged this month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 16/'2012 PAGE 1 NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM (NPDES)DISCHARGE MONITORING REPORT (DUR)PERMrTTEE NAME/ADDRESS NAME Exalon Generation Co., LLC ADDRESS 4300 Winfield Road Warrenville, U 60555-5701 FACILITY Byron Nuclear Power Station LOCATION 4450 North German Church Road DMR Mailing ZIP CODE: MAJOR (SUBR 01) CS 61010 IL0048313 PERMIT NUMBER 002-0 I -DISCHARGE NUMBER MONITORING PERIOD I Muuwvvw I I MMIDnnnnr STORMWATER RUNOFF BASIN Exteral Outfall* * *NO DISCHARGE ...I -~I- -. ...FROM I 12)01)2012 I TO0 12311/2012 l--lByron, IL 61010 ATITN: Zoe Cox/ENV SPEC QUANTITY OR LOADING QUANTITY OR CONCENTRATION NO. FREQUENCY SAMPLE PARAMETER OFTYPE: VALUE VALUE UNITS VALUE VALUE VALUE UNITS ANALYSIS Nickel, total SAMPLE ......(as Ni) MEASUREMENT 4 0106710 *~,.>. ' ~Effluent Gross W Zinc, total SAMPLE (as Zn) MEASUREMENT Effluent Gross A, ..- -,- 7.".'.- M -v-" , , ... >s, .. Ji.q Oil and Grease SAMPLE....

MEASUREMENT Effluent Gross; "';' ' 201W ..........Flow. in conduit or thru SAMPLE ...... ......treatment plant MEASUREMENT

-0. 1 0-. ." .- ... ...SAMPLE MEASUREMENT SAMPLE MEASUREMENT SAMPLE MEASUREMENT NABEnTIllE I ceaity under penalty d Sw thadw s docunent and aS attadnen were prpared under my TELEPHONE DATE PRnmPAI. uEXEcTmv ORnO dection or supemso in accidance mwih a aes desgned to swsue Ut quaited peisatvnt_____---____-_

Ippe y gather and evaelte theinlonnawlin sutnited.

Based an my nquiry oS te person o pmona J 815 403700 Benjamin P. Yournan who manage the epsten, or thse persona directly respnarte for ge9Mg the fte 0117/2013 an W is. to ft begd my loterge and debt. trute, iuralt and oip-ete. I am SIWWUREVPRINCtPLE Plant Manager aware cth there am sag:cant penaitt for subnftlg false Inductng the pawtity d EXdtUMIEtFFICER OR AREA OR PA e and brionnant for owmeing udakm AUTHORIZED AGENT CODE NUMBER MM/DD'YYYY COMMENTS AND EXPLANATION OF ANY VIOLATIONS (Reference all attachments here)1. This discharge point was not used this month.2. Them was no discharge of processed steam generator chemical cleaning wastewater during the month.EPA Form 3320-1 (Rev 01/06) Previous editions may be used. 116/2012 PAGE 2 ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 December 2012 Page 1 of 3 MONITORING DATA: WBD CRock River DATE Temperature mgd Flow deg F cfs 12/01/2012 80.4 25.55 2,180 12/02/2012 84.9 17.62 2,130 12/03/2012 90.5 18.12 2,180 12/04/2012 90.5 18.25 2,250 12/05/2012 77.1 19.23 2,120 12/06/2012 75.1 17.99 2,110 12/07/2012 74.0 19.58 2,110 12/08/2012 75.7 24.21 2,080 12/09/2012 70.9 19.38 2,120 12/10/2012 74.0 15.54 2,200 12/11/2012 72.8 21.14 2,210 12/12/2012 78.5 16.87 2,100 12/13/2012 78.5 19.45 2,150 12/14/2012 78.0 21.80 2,130 12/15/2012 75.6 22.13 2,210 12/16/2012 82.8 17.93 2,370 12/17/2012 71.3 13.12 2,310 12/18/2012 73.1 16.72 2,300 12/19/2012 74.6 17.83 2,300 12/20/2012 74.6 20.85 2,650 12/2 1/201 2 70.3 21.32 3,130 12122/2012 70.6 24.02 2,720 12/23/2012 73.0 20.59 2,520 12/24/2012 74.8 18.76 2,420 12/25/2012 73.9 16.27 2,670 12/26/2012 73.0 24.56 3,120 12/27/2012 71.8 16.42 3,080 12/28/2012 73.5 22.18 2,780 12/29/2012 73.5 23.37 2,580 12/30/2012 68.8 20.56 3,960 12/31/2012 72.8 17.91 3,940 0 0 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\December\December 2012 ATTACHO L.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 December 2012 Page 2 of 3 HYDRAZINE MONITORING:

There were no steam generator chemical cleaning solutions (or associated rinses) containing hydrazine discharged to the Cooling System Blowdown during the month of December 2012.TOTAL QUANTITY DISCHARGED:

N/A TOTAL DURATION OF DISCHARGE:

N/A COMMENTS: 1. Sodium Hypochlorite and Bromine compounds were used this month.2. There was no discharge of steam generator chemical cleaning wastewater containing hydrazine in this month.3. Flow existed through this outfall 31 of 31 days.4. Per Special Condition 24 the influent from the Rock River and effluent from Outfall 001-0 was monitored for Total Suspended Solids (TSS) this month.The Rock River TSS value was 12.0 mg/L on 12/03/2012.

The CWBD TSS value was 4.2 mg/L on 12/05/2012.

5. Rock River flow was <2400 cfs starting on December 1, 2012 therefore daily temperature calculations were required during this time period. The Rock River flow was >2400 cfs from 12/20/2012 through 12/31/2012.(Special Condition 12). Per Special Condition 12, in the event the Rock River flow is <2,400 cfs, daily calculations will be undertaken to demonstrate compliance with the water quality standard.

The calculations are based on hourly measurements, averaged over a 24-hour calendar day for Rock River flow, main Rock River temperature, CW Blowdown flow, and CW Blowdown temperature values. Results of the calculations shall be reported in the DMR on a monthly basis. Calculation results are in the table on the following page.6. There was no discharge of the 126 Priority Pollutants from cooling tower maintenance chemicals in December 2012. (Special Condition 15).K:\BYRCH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 ReportsDecember\December 2012 ATTACHO1.doc ATTACHMENT TO COOLING SYSTEM BLOWDOWN (Outfall 001-0)DISCHARGE MONITORING REPORT For Exelon Byron Station Permit IL0048313 December 2012 Page 3 of 3 Date Average Average Average Average Calculated Water Quality Rock CW M/U CW CW Temperature Standard River Temperature Blowdown Blowdown at edge of Temperature Flow (F) Flow Temperature mixing zone (F)WS) (gLm) (F) (F)12/01/12 2,150 42 13,642 79 42.8 60 12/02/12 2,097 45 13,650 82 46.6 60 12/03/12 2,147 48 13,879 87 49.4 60 12/04/12 2,223 50 13,692 79 50.6 60 12/05/12 2,091 45 13,517 70 46.1 60 12/06/12 2,076 44 13,554 75 45.2 60 12/07/12 2,080 44 13,667 74 45.6 60 12/08/12 2,048 43 13,679 73 44.6 60 12/09/12 2,075 43 13,683 73 44.1 60 12/10/12 2,169 41 13,679 70 42.0 60 12/11/12 2,208 39 13,633 67 40.1 60 12/12/12 2,110 39 13,821 74 39.8 60 12/13/12 2,141 39 13,742 75 40.0 60 12/14/12 2,132 39 13,738 75 40.0 60 12/15/12 2,196 41 13,271 77 41.7 60 12/16/12 2,363 42 12,667 75 43.0 60 12/17/12 2,315 42 12,371 70 42.4 60 12/18/12 2,301 41 12,079 72 41.6 60 12/19/12 2,307 40 13,879 71 41.1 60 K:\BYR_CH\BYRON.DB\Clerk\Monthly Discharge Monitor Rpt\2012 Reports\DecemberADecember 2012 ATTACHO1.doc