PDukeEEnergy®

JAMES R. MORRISVice President

Catawba Nuclear Station4800 Concord Rd. / CN01 VPYork, SC 29745-9635

803 831 4251

803 831 3221 fax

March 31, 2008

U.S. Nuclear Regulatory CommissionAttention: Document Control DeskWashington, D.C. 20555

Subject: Duke Power Company LLC d/b/a Duke Energy Carolinas, LLC(Duke)Catawba Nuclear Station, Units 1 and 2Docket Nos. 50-413, 4142007 10CFR50.59 Summary Report

Attached please find a report containing a brief description ofchanges, test, and experiments, including a summary of the safetyevaluation for each, for Catawba Nuclear Station, Units 1 and 2for the year 2007. This report is submitted pursuant theprovisions of 10CFR50.59(d) (2) and 10CFR50.4.

If there are any questions regarding this report, please contactA. Jones-Young at (803) 831-3051.

Sincerely,

Morris

Attachments

www. duke-energy. corn

U. S. NRCMarch 31, 2008Page 2

xc (with attachment):

V.M. McCreeRegional Administrator, Region IIU.S. Nuclear Regulatory Commission61 Forsyth Street, S.W., Suite 23T85Atlanta, GA 30303

J.F. Stang, Jr. (addressee only)NRC Senior Project ManagerU.S. Nuclear Regulatory CommissionMail Stop 8-G9A11555 Rockville PikeRockville, MD 20852-2738

A.T. SabischNRC Senior Resident InspectorCatawba Nuclear Station

U.S. NRCMarch 31, 2008Page 3

bxc:

A. Jones-YoungELLFile CN:801.01CNS Date File

CN01RCECO5OCN04MDCN01SA

bxc ) (w/o attachments):

R. D. HartK. L. AsheB. G. DavenportR. L. GillNCMPA-1NCEMCRMPASREC

CN01RCMN01RCON03RCEC050

U.S. NRCCatawba Nuclear Station2007 IOCFR50.59 Summary ReportMarch 31, 2008Page 1 of 9

Type: Procedure change Unit: 2

Title: OP/2/A/6200/050, Zinc Acetate Addition to theReactor Coolant System, Revision 000

Description:

Evaluation:

OP/2/A/6200/050 is a new procedure for theaddition of zinc acetate to the reactorcoolant system via the Nuclear Sampling (NM)system. Catawba is initiating zinc additionto the reactor coolant system based onindustry experience that indicates thatcontrolled addition of zinc to reactorcoolant can result in reduction of outagedose rates around various*primary systemcomponents. Dose rate reduction occursbecause zinc displaces some of the nickel-and radiocobalt present on wetted surfacesof the reactor coolant system. Thedisplaced nickel and cobalt in the reactorcoolant system can be removed through normaluse of letdown flow through mixed-beddemineralizers.

This evaluation is for procedure,OP/2/A/6200/050, Zinc Acetate Addition tothe Reactor Coolant System, Revision 0.This procedure is used to inject zincacetate into the Unit 2 reactor coolantsystem for the purpose of reducingoutage dose rates around primary systems.Zinc acetate is added to the reactor coolantSystem using a skid connected to the nuclearsampling system. There are physical andprocedural controls on injection flow rateand volume. Evaluation of zinc addition toreactor coolant system and operatingexperience with zinc addition, within thephysical and procedural limits of the zincaddition skid and this procedure, show noadverse impact on plant equipment oraccident probabilities. Zinc addition toreactor coolant system can increase levelsof nickel and radiocobalt in the systemduring operation but accident consequencesare unaffected. Chemical properties of thereactor coolant, notably pH, is not changedby the addition of zinc acetate. Zincaddition can cause a slight increase in cruddeposition on fuel cladding; however, thereis no effect on the cladding as a fissionproduct barrier. NRC approval is not

U.S. NRCCatawba Nuclear2007 IOCFR50.59March 31, 2008Page 2 of 9

StationSummary Report

required prior to starting zinc addition tothe reactor coolant system. No TechnicalSpecification changes are required and noother SAR document changes are required.

Type:

Title:

Miscellaneous Item Units: 1 and 2

Catawba LOCA Dose Analysis Revision toPreclude a LOCADOSE Code Error

Description: An error was discovered in the computer codeLOCADOSE used in the analysis of the designbasis Loss of Coolant Accident (LOCA), atCatawba Nuclear Station. The error wasassociated with the use of containment sprayfor washing out contamination from thecontainment environment. The dose analysiswas revised to preclude the code error. To offsetsome of the effect of the error correction, an overlyconservative analysis assumption was alsorevised. These two changes to the doseanalysis (error work around and assumptionchange) have been reviewed separately. A 10CFR 50.59 screen was performed for these twodose analysis changes. The screendetermined that a 10 CFR 50.59 evaluationwas not required for the change in theanalysis assumption of particulate spraywashout constants. However, the code errorwork around screened in as a change to amethod of evaluation. - Therefore, the scopeof this 10 CFR 50.59 evaluation will focusonly on the work around to preclude the codeerror.

The proposed activity under evaluation is achange to the CNS UFSAR to update thedescription of the calculation model andcalculated dose results from the LOCA. ThisIOCFR50.59 evaluation demonstrates that theUFSAR Chapter 15 accident dose re-analysisdoes not satisfy any of the criteria inl0CFR50.59(c) (2) for a license amendment via10CFR50.90. UFSAR sections which will require revisiondue to these dose analysis changes are Tables 15-14,

Evaluation:

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15-40 and 15-81 and Sections 15.6.5.3 and 15.9.

No Technical Specification changes arerequired, and the proposed activity may beimplemented without prior NRC approval.

Type:

Title:

Design Change Unit: 1

CD-101416, INV-63B, NCP lB Seal ReturnIsolation, AOV in the Fail-Safe OPENPosition, with Control Power Removed andIncapable of being Closed (PIP C07-0367)

Description:

Evaluation:

1NV-63B, reactor coolant pump (NCP) 1B SealReturn Isolation is an air operated globevalve which operates on open-shut operationand fails in the open position (i.e.,following a loss of air). During normaloperation, 1NV-63B is in an open position.After trouble shooting identified a groundfault in the valve's control circuit, 1NV-63B control power was removed such that thevalve cannot be closed. This evaluationsupports a temporary engineering change CD-101416 that will allow 1NV-63B to remain inthe fail-safe open position until repairscan be performed at the next refuelingoutage.

Leakage from the reactor coolant pump shaftis controlled by three shaft seals arrangedin series. Between the number 1 seal andnumber 2 seal, most of the leakage,.approximately 3 gpm, leaves the pump via thenumber 1 seal return line. 1NV-63B is anair operated control valve located in theseal return line of the 1B reactor coolantpump, which operates on open-shut operationand fails in the open position (i.e.,following a loss of instrument air). Duringnormal operation, 1NV-63B is in an openposition. After troubleshooting identifieda ground fault in the control circuit, INV-63B control power was removed such that thevalve cannot be closed. 1NV-63B is not requiredto perform a safety function in shutting down theunit to cold shutdown or in mitigating the consequences

U.S. NRCCatawba Nuclear Station2007 IOCFR50.59 Summary ReportMarch 31, 2008Page 4 of 9

of an accident. UFSAR Section 5.4.1.3.1states that following warning of excessivereactor coolant pump number 1 seal returnflow, operator action should be taken toclose the seal return isolation valve (i.e.,1NV-63B on lB pump). This evaluation showsthat maintaining 1NV-63B in the fail-safeopen position has no impact on pump sealperformance and does not impact UFSARaccident analysis.

This evaluation addressed two separatemodes-of-failure for a postulated NCP sealfailure event. For a reactor coolant pumpseal failure event where the number 1 sealis not functional, but the number 2 sealremains operational, leakage from the failedRCP seal will not exceed 76 gpm and loss ofinventory for the reactor coolant systemremains within the capability of the reactormakeup system. For this postulated event,the evaluation shows that there are nofailure modes that would result in a number2 seal failure; thereby, this event does notpropagate to cause a more serious fault.

For a reactor coolant pump seal failureevent where both the number 1 seal andnumber 2 seal are not functional, thereactor coolant pump seal leakage will notexceed 480 gpm. This leak rate is boundedby the UFSAR Small Break Loss of CoolingAccident (SBLOCA), and again does notpropagate to cause a more serious fault.

With 1NV-63B in the fail-safe open position,the consequence of a reactor coolant pumpseal failure remains bounded by currentanalysis for all UFSAR evaluatedmalfunctions and analyzed accidents. Thiscondition does not result in a design basislimit for a fission product barrier beingexceeded or altered, and does not involve adeparture from a method of evaluation usedin establishing the design basis or in thesafety analysis. There is no TechnicalSpecification change required as a result ofthis change.

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StationSummary Report

Type:

Title:

Design Changes Units: land 2

Description:

CD100702 and CD200705 Restore Control Air toInlet, Outlet and Bypass Dampers to VA toallow for Normal ABFU Bypass Operation andRedundant Single Failure Proof EmergencyOperation - Also, revise Control Air from 25psi to 100 psi Operation

The Auxiliary Building Filtered ExhaustVentilation System (VA) was initiallydesigned to operate filter units ABFU-I(2)Aand ABFU-I(2)B in a bypass alignment duringnormal operation. Filter unit dampersautomatically realign the filter units tothe filter mode upon receipt of a SafetyInjection signal (SI) or radiation monitorhigh alarm from OEMF-41 (Auxiliary Building)or I(2)EMF-35, 36, 37 (Unit Vent Stacks).PIP C95-0007 identified single failureconcerns that could allow one of the filterunits to continue to operate in the filterbypass alignment following a Design BasisAccident(DBA) . Operation of the filter unitin a bypass alignment during a DBA couldallow potentially contaminated air to beexhausted from the Auxiliary Building andexceed applicable dose limits. To resolvethe immediate single failure concerns, minormodifications were completed in 1995 per PIPC95-0007, CA#2. Those modifications removedcontrol air from Unit 1(2) VA train A and Bfilter unit dampers causing the filter unitsto operate continuously in the filteredalignment. Operation of VA in a continuousfiltered alignment has significantlyincreased material, maintenance andoperations support requirements caused byfrequent filter and carbon change outs.Design Changes CD100702 (along with DesignChanges CD100700 and CD100701 - processedseparately) will allow Unit 1(2) VA filterunits to operate in a filter bypassalignment during normal operation. Singlefailure concerns identified by PIP C95-0007will be removed by this modification.

U.S. NRCCatawba Nuclear2007 10CFR50.59March 31, 2008Page 6 of 9

StationSummary Report

Control air will be restored to VA filterinlet isolation damper, outlet isolationdamper and existing bypass damper. Thismodification will also revise the supply ofcontrol air through the Train A and Bsolenoid valves by eliminating the need forthe downstream pilot valves currently usedto supply 100 psi air to the damperactuators. The existing design utilizes 25psi air to the Train A and B solenoidvalves and that will be changed to 100 psiair supply. A direct interface of 100 psiair to the actuators will be supplied fromTrain A and B solenoid valves. The airtubing is designed for these conditions.Since Instrument Air is not Safety Related,the design provides for the absence of airto allow the spring actuators to fail to thesafe position (open or closed depending onthe damper location).

Design Changes CD100702 and CD200705 hasbeen documented with a 50.59 Evaluationrather than a 50.59 Screening. All of theresponses to the eight 50.59 Evaluationquestions are "No". Thus, a Licenseamendment is not necessary. UFSAR sections9.4.3.2, 7.6.12, Table 9-28, and Figure 9-123 will be revised as indicated in themodification package. A change is needed tothe Tech Spec BASES and is included in themodification package.

No changes to any Technical Specificationare needed. Thus, prior NRC review will notbe required.

Evaluation:

Type:

Title:

Miscellaneous Item

C2C16 Reload Design

Unit: 2

Description: The reload change document identifieschanges in key physics parameters, operatinglimits, and design parameters between cycles15 and 16 for the purpose of identifyingpossible impacts to reactivity management,technical specifications and operations.

U.S. NRCCatawba Nuclear Station2007 IOCFR50.59 Summary ReportMarch 31, 2008Page 7 of 9

The core design changes identified betweencycle 15 and cycle 16 are briefly summarizedbelow:

1. Nominal EOC burnup window reducedfrom 510 to 471 EFPD.

2. The fuel feed batch size for cycle 15 was 77 andthe fuel feed batch for cycle 16 is 68.

3. Fuel feed batch central region enrichment(w/o U-235) changed from 52 assemblies @4.4, 24assemblies @ 4.73, and 1 assembly at 3.80 in cycle15 to 40 assemblies @4.38 and 28 assemblies @ 4.90in cycle 16.

4. Number of integral fuel burnable absorber (IFBA)pins changed from 5184 to 6400.

5. A total of 656 wet annular burnable absorber(WABA) pins are utilized in. cycle 16 while. cycle15 utilized 848. WABAs have been used in otherCatawba fuel cycles and are therefore not a newcore design parameter.

6. Minor power distribution and physics parameterchanges are noted from Cycle 15.

7. The cycle 15 axial flux difference 100% full powernegative limit was -20% and the cycle 16 axialflux difference 100% full power negative limit is-18%.

There are no fuel assembly component designchanges, no Technical Specification changes,and no UFSAR changes associated with theoperation of C2C16.

Evaluation: The C2C16 Reload Design Safety Analysis.Review (REDSAR), performed in accordancewith Nuclear Engineering Division workplaceprocedure NE-102, "Workplace Procedure forNuclear Fuel Management," and the C2C16Reload Safety Evaluation, confirm theupdated final safety analysis report (UFSAR)Chapter 15 accident analysis remain boundingwith respect to the C2C16 safety analysisreactor physics parameters. The safetyanalysis reactor physics parameters methodis described in topical report DPC-NE-3001-PA, Multidimensional Reactor Transients andSafety Analysis Physics ParametersMethodology."

N

The C2C16 core reload is similar to pastcycle core designs, with a design generatedusing NRC approved methods. The C2C16 CoreOperating Limits Report is prepared in

U.S. NRCCatawba Nuclear Station2007 10CFR50.59 Summary ReportMarch 31, 2008Page 8 of 9

accordance with Technical Specification5.6.5 and submitted to the NRC in accordancewith 10 CFR 50.4. Additionally, applicablesections of Technical Specifications and theUFSAR have been reviewed. No changes to TechnicalSpecifications or the UFSAR are necessary to supportoperation of C2C16.

Type:

Title:

Procedure change Unit: 1

Description:

Evaluation:

OP/l/A/6200/050, Zinc Acetate Addition tothe Reactor Coolant System, Revision 000

OP/l/A/6200/050 is a new procedure for theaddition of zinc acetate to the reactorcoolant system via the Nuclear Sampling (NM)system. Catawba is initiating zinc additionto the reactor coolant system based onindustry experience that indicates thatcontrolled addition of zinc to reactorcoolant can result in reduction of outagedose rates around various primary systemcomponents. Dose rate reduction occursbecause zinc displaces some of the nickeland radiocobalt piresent on wetted surfacesof the reactor coolant system. Thedisplaced nickel and cobalt in the reactorcoolant system can be removed through normaluse of letdown flow through mixed-beddemineralizers.

This evaluation is for procedure,OP/2/A/6200/050, Zinc Acetate Addition tothe Reactor Coolant System, Revision 0.This procedure is used to inject zincacetate into the Unit 2 reactor coolantsystem for the purpose of reducingoutage dose rates around primary systems.Zinc acetate is added to the reactor coolantsystem using a skid connected to the nuclearsampling system. There are physical andprocedural controls on injection flow rate

and volume. Evaluation of zinc addition toreactor coolant system and operatingexperience with zinc addition, within thephysical and procedural limits of the zincaddition skid-and this procedure, show no

U.S. NRCCatawba Nuclear Station2007 10CFR50..59 Summary ReportMarch 31, 2008Page 9 of 9

adverse impact on plant equipment oraccident probabilities. Zinc addition toreactor coolant system can increase levelsof nickel and radiocobalt in the systemduring operation but accident consequencesare unaffected. Chemical properties of thereactor coolant, notably pH, is not changed bythe addition of zinc acetate. Zincaddition can cause a slight increase' in cruddeposition on fuel cladding; however, thereis no effect on the cladding as a fissionproduct barrier. NRC approval is notrequired prior to starting zinc addition tothe reactor coolant system. No TechnicalSpecification changes are required and noother SAR document changes are required.