ML061250341

Fort Calhoun, Unit 1 - Request for Additional Information Related to LAR for Updated SAR Clarification of Operator Action During Loss of Main Feedwater Event (TAC No. MC7524)

ML061250341
Person / Time
Site:	Fort Calhoun
Issue date:	05/05/2006
From:	Wang A B NRC/NRR/ADRO/DORL/LPLG
To:	Ridenoure R T Omaha Public Power District
Wang A B
References
TAC MC7524
Download: ML061250341 (5)

Text

May 5, 2006Mr. R. T. Ridenoure Vice President - Chief Nuclear Officer Omaha Public Power District Fort Calhoun Station FC-2-4 Adm.

Post Office Box 550 Fort Calhoun, NE 68023-0550

SUBJECT:

FORT CALHOUN STATION, UNIT 1 - REQUEST FOR ADDITIONALINFORMATION RELATED TO LICENSE AMENDMENT REQUEST FOR UPDATED SAFETY ANALYSIS REPORT CLARIFICATION OF OPERATOR ACTION DURING LOSS OF MAIN FEEDWATER EVENT (TAC NO. MC7524)Dear Mr. Ridenoure

By letter dated July 1, 2005, Omaha Public Power District (OPPD) submitted a licenseamendment request for the Fort Calhoun Station, Unit 1. The license amendment proposed torevise the Updated Safety Analysis Report (USAR), Section 14.10, to credit operator action during the Loss of Main Feedwater Event. The proposed change will add a description of anexisting Emergency Operating Procedure operator action to isolate steam generator blowdown within 15 minutes of reactor trip during a loss of main feedwater event to the USAR.The Nuclear Regulatory Commission (NRC) staff has reviewed OPPD's submittal and had ateleconference on April 24, 2006, with OPPD to discuss this submittal. The NRC staff hasdetermined that additional information is needed to complete our review. A request for additional information (RAI) is enclosed. This request was discussed with Thomas Matthews of your staff on May 1, 2006, and it was agreed that a response would be provided within 6 weeks of receipt of this letter.If you have any questions, please contact me at (301) 415-1445.Sincerely,/RA/Alan B. Wang, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No.

50-285

Enclosure:

RAIcc w/encl: See next page May 5, 2006Mr. R. T. Ridenoure Vice President - Chief Nuclear Officer Omaha Public Power District Fort Calhoun Station FC-2-4 Adm.

Post Office Box 550 Fort Calhoun, NE 68023-0550

SUBJECT:

FORT CALHOUN STATION, UNIT 1 - REQUEST FOR ADDITIONALINFORMATION RELATED TO LICENSE AMENDMENT REQUEST FOR UPDATED SAFETY ANALYSIS REPORT CLARIFICATION OF OPERATOR ACTION DURING LOSS OF MAIN FEEDWATER EVENT (TAC NO. MC7524)Dear Mr. Ridenoure

By letter dated July 1, 2005, Omaha Public Power District (OPPD) submitted a licenseamendment request for the Fort Calhoun Station, Unit 1. The license amendment proposed torevise the Updated Safety Analysis Report (USAR), Section 14.10, to credit operator action during the Loss of Main Feedwater Event. The proposed change will add a description of anexisting Emergency Operating Procedure operator action to isolate steam generator blowdown within 15 minutes of reactor trip during a loss of main feedwater event to the USAR.The Nuclear Regulatory Commission (NRC) staff has reviewed OPPD's submittal and had ateleconference on April 24, 2006, with OPPD to discuss this submittal. The NRC staff hasdetermined that additional information is needed to complete our review. A request for additional information (RAI) is enclosed. This request was discussed with Thomas Matthews of your staff on May 1, 2006, and it was agreed that a response would be provided within 6 weeks of receipt of this letter.If you have any questions, please contact me at (301) 415-1445.Sincerely,/RA/

Alan B. Wang, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No.

50-285

Enclosure:

RAIcc w/encl: See next page DISTRIBUTION

PUBLICLPLIV R/FRidsNrrPMAWang DGuha, NRR/ADROSSun, NRR/ADESRidsNrrDorlLpl4 (DTerao)RidsRgn4MailCenter (DGraves)RidsOgcRpRidsAcrsAcnwMailCenterRidsNrrDorlDprRidsNrrDssSpwb (JNakowski)

RidsNrrLALFeizollahi RidsNrrPMBSingalADAMS ACCESSION NO.: ML061250341OFFICELPL4/PMLPL4/LALPL4/BCNAMEAWang; mxr4LFeizollahiDTeraoDATE5/5/065/5/065/5/06OFFICIAL RECORD COPY REQUEST FOR ADDITIONAL INFORMATIONREGARDING UPDATED SAFETY ANALYSIS REPORT (USAR) CLARIFICATIONOMAHA PUBLIC POWER DISTRICTFORT CALHOUN STATIONDOCKET NO. 50-285By letter dated July 1, 2005, Omaha Public Power District (OPPD), the licensee for the FortCalhoun Station, Unit 1 (FCS), requested a license amendment to permit FCS to revise the USAR, Section 14.10, to credit operator action during the Loss of Main Feedwater (LMFW)

Event. The proposed change will add a description of an existing Emergency OperatingProcedure operator action to isolate steam generator blowdown within 15 minutes of reactor trip during an LMFW event to the USAR. The operator action is intended to assist the auxiliaryfeedwater system in performing its design function of maintaining adequate steam generator(SG) water level for decay heat removal once the auxiliary feedwater actuation signal isactuated. OPPD requests approval of the proposed change to support plant operationsfollowing the 2006 outage during which the SGs, pressurizer, and reactor vessel head will bereplaced. The Nuclear Regulatory Commission (NRC) staff has performed a preliminary review of thehuman performance associated changes in the license amendment request. The licensee's responses to the following request for additional information with regard to containment analysis aspects of the license amendment are needed for the NRC staff to complete its review.1.Page 22 of Attachment 4 to the licensee's letter of July 1, 2005, stated that for thefeedwater line break (FLB) analysis that "SG blowdown flow is automatically and conservatively isolated at 49.03 sec...." The NRC staff has noted that in FCS TechnicalSpecification Table 2-1, a containment pressure high signal (CPHS) or a pressurizer pressure low signal (PPLS) would actuate a containment isolation actuation signal thatisolates SG blowdown flow. As such:a.Please indicate which signal (a CPHS or a PPLS) was credited to automaticallyisolate the SG in the analysis. Demonstrate that the FLB case with SGblowdown isolation occurring at 49.03 seconds is the limiting break case (considering full-break sizes of the FLB) with respect to the acceptance criterion of the peak post-trip hot-leg temperature of 600 degrees F.b.If OPPD credited a CPHS to isolate the SG blowdown flow, please discuss howthe CPHS time was determined for FLB cases with break sizes ranging from the maximum break size to the smallest credible size.c.Please provide a description of the containment model to show its adequacy forthe CPHS time determination (with respect to prediction of a lower containment pressure resulting in a high CPHS time).

d.For the small-size FLBs that would not result in a CPHS, please discuss theavailable Emergency Operating Procedures for the operator to manually isolate SG blowdown flow, and show that the proposed operation action (15 minutesafter a reactor trip) for the LMFW event is sufficient for the FLB event.

April 2006Ft. Calhoun Station, Unit 1 cc:Winston & Strawn ATTN: James R. Curtiss, Esq.

1700 K Street, N.W.

Washington, DC 20006-3817ChairmanWashington County Board of Supervisors

P.O. Box 466 Blair, NE 68008Mr. John Hanna, Resident InspectorU.S. Nuclear Regulatory Commission

P.O. Box 310 Fort Calhoun, NE 68023Regional Administrator, Region IVU.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005Ms. Julia Schmitt, Manager Radiation Control Program Nebraska Health & Human Services R & L Public Health Assurance 301 Centennial Mall, South P.O. Box 95007 Lincoln, NE 68509-5007Mr. David J. Bannister, ManagerFort Calhoun Station Omaha Public Power District Fort Calhoun Station FC-1-1 Plant

P.O. Box 550 Fort Calhoun, NE 68023-0550Mr. Joe L. McManisManager - Nuclear Licensing Omaha Public Power District Fort Calhoun Station FC-2-4 Adm.

P.O. Box 550 Fort Calhoun, NE 68023-0550Mr. Daniel K. McGheeBureau of Radiological Health Iowa Department of Public Health Lucas State Office Building, 5th Floor 321 East 12th Street Des Moines, IA 50319