ML061530295

Request for Additional Information, Ultimate Heat Sink License Amendment Request

ML061530295
Person / Time
Site:	LaSalle
Issue date:	06/15/2006
From:	Sands S Plant Licensing Branch III-2
To:	Crane C Exelon Generation Co
Sands S,NRR/DORL, 415-3154
References
TAC MC0336, TAC MC0337
Download: ML061530295 (7)

Text

June 15, 2006Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LASALLE COUNTY STATION, UNITS 1 AND 2 - REQUEST FOR ADDITIONALINFORMATION RELATED TO ULTIMATE HEAT SINK LICENSE AMENDMENT REQUEST (TAC NOS. MD0336 AND MD0337)

Dear Mr. Crane:

By letter to the Nuclear Regulatory Commission (NRC) dated March 13, 2006 (AgencywideDocuments Access and Management System Accession No. ML060720507), Exelon Generation Company, LLC submitted a request to change the technical specifications (TS) related to TS 3.7.3, "Ultimate Heat Sink," for the LaSalle County Station, Units 1 and 2.The NRC staff is reviewing your submittal and has determined that additional information isrequired to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on June 1, 2006, it was agreed that LaSalle County Station would provide a response within 30 days of the date of this letter. The NRC staff considers that timely responses to requests for additional information helpensure sufficient time is available for staff review and contribute toward the NRC's goal ofefficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-3154.Sincerely,/RA/Stephen P. Sands, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket Nos. 50-373 and 50-374

Enclosure:

Request for Additional Informationcc w/encl: See next page June 15, 2006Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LASALLE COUNTY STATION, UNITS 1 AND 2 - REQUEST FOR ADDITIONALINFORMATION RELATED TO ULTIMATE HEAT SINK LICENSE AMENDMENT REQUEST (TAC NOS. MD0336 AND MD0337)

Dear Mr. Crane:

By letter to the Nuclear Regulatory Commission (NRC) dated March 13, 2006 (AgencywideDocuments Access and Management System Accession No. ML060720507), Exelon Generation Company, LLC submitted a request to change the technical specifications (TS) related to TS 3.7.3, "Ultimate Heat Sink," for the LaSalle County Station, Units 1 and 2.The NRC staff is reviewing your submittal and has determined that additional information isrequired to complete the review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on June 1, 2006, it was agreed that LaSalle County Station would provide a response within 30 days of the date of this letter. The NRC staff considers that timely responses to requests for additional information helpensure sufficient time is available for staff review and contribute toward the NRC's goal ofefficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-3154.Sincerely,/RA/Stephen P. Sands, Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket Nos. 50-373 and 50-374

Enclosure:

Request for Additional Information DISTRIBUTION:PUBLICLPL3-2 R/FRidsNrrDorlLpl3-2 RidsNrrPMSSandsRidsNrrLADClarkeRidsAcrsAcnwMailCenterRidsOgcRpRidsRgn3MailCenterRidsNrrDorlDprRidsNrrDeEicbADAMS Accession Number: ML061530295OFFICELPL3-2/PMLPL3-2/LAEICB/BCLPL3-2/BCNAMESSands:mwDClarkeAHowe*DCollinsDATE06/15/200606/15/200606/2/200606/15/2006OFFICIAL RECORD COPY LaSalle County Station Units 1 and 2 cc:

Site Vice President - LaSalle County StationExelon Generation Company, LLC 2601 North 21st Road Marseilles, IL 61341-9757LaSalle County Station Plant ManagerExelon Generation Company, LLC 2601 North 21st Road Marseilles, IL 61341-9757Regulatory Assurance Manager - LaSalleExelon Generation Company, LLC 2601 North 21st Road Marseilles, IL 61341-9757U.S. Nuclear Regulatory CommissionLaSalle Resident Inspectors Office 2605 North 21st Road Marseilles, IL 61341-9756Phillip P. Steptoe, EsquireSidley and Austin One First National Plaza Chicago, IL 60603Assistant Attorney General100 W. Randolph St. Suite 12 Chicago, IL 60601ChairmanLaSalle County Board 707 Etna Road Ottawa, IL 61350Attorney General500 S. Second Street Springfield, IL 62701ChairmanIllinois Commerce Commission 527 E. Capitol Avenue, Leland Building Springfield, IL 62706Robert Cushing, Chief, Public Utilities DivisionIllinois Attorney General's Office 100 W. Randolph Street Chicago, IL 60601Regional AdministratorU.S. NRC, Region III 801 Warrenville RoadLisle, IL 60532-4351Illinois Emergency Management Agency Division of Disaster Assistance &

Preparedness 110 East Adams Street Springfield, IL 62701-1109Document Control Desk - LicensingExelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555Senior Vice President of OperationsExelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555Vice President - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 LaSalle County Station Units 1 and 2- 2 -Director - Licensing and Regulatory AffairsExelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555Assistant General CounselExelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348Manager Licensing - Dresden, Quad Cities and ClintonExelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 ENCLOSUREREQUEST FOR ADDITIONAL INFORMATIONLASALLE COUNTY STATION, UNITS 1 AND 2DOCKET NOS. 50-373 AND 50-374In reviewing the Exelon Generation Company's (Exelon's) license amendment request submittaldated March 13, 2006, related to ultimate heat sink (UHS) for the LaSalle County Station, Units1 and 2 (LaSalle), the NRC staff has determined that the following information is needed inorder to complete its review:1.Show that the temperatures in the two circulating water intake canals are sufficientlyrepresentative of each other and of the UHS temperature as assumed in the safety analysis to support the use of the averaged temperature at both units. Show how theserelationships remain valid when one unit is out of service, or explain how this will beaccommodated in the technical specification (TS) for the other unit. (Category 2.a)2. Describe any thermowell modifications or adaptors required for the installation of theresistance temperature detectors (RTDs). Confirm that the RTD insertion length is compatible with the thermowells. Identify any seismic requirements applicable to this installation; for example, if safety-related cooling water is extracted from these canals, there may be seismic II/I considerations. (Category 2.a)3. The request indicates that the existing thermocouple wires will be used for the RTDs,and that temperature compensator modules will be used to correct any signal effects. Where will these temperature compensator modules be located? What is the specificcompensation provided, and how does this account for: (Category 2.a)(a)thermocouple wire resistence, especially considering that the RTDs are using a2-wire, rather than 3- or 4-wire configuration, and (b)dissimilar metallic junction at both ends of the thermocouple cables. Pleaseexplain how these effects are addressed in the uncertainty evaluation. 4. Provide the detailed uncertainty evaluation, showing the source of all input informationand the full derivation of all results and conclusions. (Category 2.a)5. Describe the configuration (in regard to the acquisition and exchange of thesetemperature measurement data) of the Data Acquisition System, Plant Process Computer for each unit, and the data communications in each unit and between units as they presently exist and as they would exist following the implementation of the requested change. (Category 2.a)6. What method or procedures for determining the UHS temperature reading, used tosatisfy the TS requirement, will be used after all four new RTDs are installed? Includedetails on handling failed inputs (if one RTD fails in one unit, if one RTD fails in each unit, if two fail in one unit, if two fail in one unit and one fails in the other unit).

(Category 2.a) 7. How are the temperature values presented to the operators and system engineerincluding any alarms, warnings, or other identification of status or failures?

(Category 2.a)8. Describe the type of RTD to be used, and the calibrated range of the temperaturemeasurement. (Category 2.a)9. How frequently will the new RTD readings be sampled and how frequently are theassociated calculations performed? (Category 2.a)10. The statistical theory upon which the assumed accuracy improvement is partly basedrequires statistical independence among the measurements. How are the common-mode uncertainty elements, such as environmental effects and common maintenance and test equipment, accounted for in the analysis? (Category 2.a)11. How were any aging effects on RTD and component accuracy accounted for in theuncertainty calculations? (Category 2.a)12.Describe the calibration and surveillance procedures to be implemented to maintain theaccuracy of the individual temperature measurements. (Category 2.a) RAI CATEGORIES(Select only one, most dominant category for each RAI question)1.More information is needed because of:a. complexity of requestb. first-of-a-kind nature of request

c. NRC change in regulatory significance or focusd. NRC questions on previously used methodology or guidancee. licensee change to previously used methodology

f. licensee reduction in current safety margin2.The review can not be completed without additional explanation or clarification of:a. input variables or analytical assumptionsb. methodology used or results obtained

c. applicability or bounding nature of third party analyses or data correlationsd. differences from NRC guidance documents (SRP, RG, etc.)e. no significant hazards consideration discussion

f. environmental considerations discussion

g. applicable regulatory requirements discussion

h. information that appears to be incorrect and needs to be corrected

i. response to previous RAI appears inadequate3.Reviewer requesting information even though the question is, or the question asks for:a. not directly related to the requestb. inconsistent with applicable codes, standards, RGs, or SRP sections

c. information accessible from readily available sources and was explicitly referenced

d. information does not appear needed given the precedent cases discussed in the request

e. information that is not safety significant or pertinent to the regulatory findingf. information that is known to engineers who work in the general technical area

g. going beyond the current licensing basis and doesn't need to be asked

h. a formal commitment4.Other (please specify)