ML20197D052

Forwards RAI Re Bg&E Feedwater Sys (5.9) Integrated Plant Assessment Technical Rept.Response Requested within 30 Days of Receipt of Ltr

ML20197D052
Person / Time
Site:	Calvert Cliffs
Issue date:	09/01/1998
From:	Dave Solorio NRC (Affiliation Not Assigned)
To:	Cruse C BALTIMORE GAS & ELECTRIC CO.
References
TAC-M95453, TAC-M95454, TAC-M99178, NUDOCS 9809150221
Download: ML20197D052 (6)

Text

{{#Wiki_filter:. _ . - . - - . . -. . - . - . - - - - - - . _ - _ _ . . . , - . - - . - . - - . . - . -

    .                 4 s                                                                            September h ,1998                                                                   l Mr. Charles H. Cruse, Vice President Nuclear Energy Division
                        - Baltimore Gas and Electric Company 1650 Calvert Cliffs Parkway                                                                                                               )

l Lusby, MD 20657-47027

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE I CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS.1 & 2, INTEGRATED l PLANT ASSESSMENT FOR THE FEEDWATER SYSTEM (TAC NOS. M95453, M95454, AND M99178)

Dear Mr. Cruse:

By letter dated May 23,1997, Baltimore Gas and Electric Company (BGE) submitted for review the Feedwater System (5.9) integrated plant assessment technical report as attached to the

                         " Request for Review and Approval of System and Commodity Reports for License Renewal."

BGE requested that the Nuclear Regulatory Commission (NRC) staff review the Feedwater System (5.9) integrated plant assessment technical report to determine if the report meet the requirements of 10 CFR 54.21(a), " Contents of application-technicalinformation," and the demonstration required by 10 CFR 54.29(a)(1), " Standards for issuance of a renewed license," to support an application for license renewal if BGE applied in the future. By letter dated April 8,1998, BGE formally submitted its license renewal application. l The NRC staff reviewed the Feedwater System (Section 5.9) integrated plant assessment against the requirements of 10 CFR 54.21(a)(1) and 10 CFR 54.21(a)(3). By letter dated . February 13,1998, the staff forwarded requests for additional information to BGE in order to  ; give BGE additional time to prepare its responses while the staff was continuing its review of the subject reportJ Based on the continued review of Section 5.9 of BGE's license renewal application, the staff has identified in the enclosure additional areas beyond those outlined in the February 13,1998, letter where information is needed to complete its review. )

                        ' Please provide a schedule by letter or telephonically for the submittal of your responses within 30 days of the receipt of this letter. Additionally, the staff would be willing to meet with BGE prior to the submittal of the responses to provide clarifications of the staffs requests for additionalinformation.                                                                                                                   ,

Sincerely, WW David L. Solorio, Project Manager > License Renewal Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation )

Enclosure:

As stated i Docket Nos. 50-317,50-318 g i cc:' See next page DISTRIBUTION: r[ $ I { g  : See next page ' ' DOC U M ENT i LAME:G :\ WOR KING \LE E\FWS_RAllTR -/ OFFICE ' LA:PDI-1j PDLR/DRPM (FQLR/DRff91:ASCPDLR/DRP,M:D , NAME SlJttl# DSolorid BPraK CGrimes@ , DATE -{/IiS8 $/) /98 / 8/ /k $/l /98 OFFICIAL RECORD COPY 9909150221 980901 "

• Y <

                         ;" ""                       S'# m                                      gg IR.E CEN

Mr. Charles H. Cruse - Calvert Cliffs Nuclear Power Plant Baltimore Gas & Electric Company Unit Nos.1 and 2 l cc: i President Mr. Joseph H. Walter, Chief Engineer i Calvert County Board of Public Service Commission of Commissioners Magland 175 Main Street Engineering Division Prince Frederick, MD 20678 6 St. Paul Centre Baltimore, MD 21202-6806 l James P. Bennett, Esquire Counsel Kristen A. Burger, Esquire Baltimore Gas and Electric Company Maryland People's Counsel l P.O. Box 1475 6 St. Paul Centre Baltimore, MD 21203 Suite 2102 l Baltimore, MD 21202-1631 Jay E. Silberg, Esquire , Shaw, Pittman, Potts, and Trowbridge Patricia T. Birnie, Esquire 2300 N Street, NW Co-Director Washington, DC 20037 Maryland Safe Energy Coalition

_ P.O. Box 33111 1 l Mr. Thomas N, Prichett, Director Baltimore, MD 21218 '

NRM Calvert Cliffs Nuclear Power Plant Mr. Loren F. Donatell j 1650 Calvert Cliffs Parkway NRC Technical Training Center l Lusby, MD 20657-4702 5700 Brainerd Road Chattanooga, TN 37411-4017 Resident inspector U.S. Nuclear Regulatory Commission David Lewis l P.O. Box 287 Shaw, Pittman, Potts, and Trowbridge St. Leonard, MD 20685 2300 N Street, NW Washington, DC 20037 Mr. Richard I. McLean Nuclear Programs Douglas J. Walters Power Plant Research Program Nuclear Energy Institute Maryland Dept. of Natural Resources 1776 i Street, N.W. Tawes State Office Building, B3 Suite 400 Annapolis, MD 21401 Washington, DC 20006-3708 DJW@NEl.ORG Regional Administrator, Region i U.S. Nuclear Regulatory Commission Barth W. Doroshuk 475 Allendale Road Baltimore Gas and Electric Company King of Prussia, PA 19406 Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway NEF ist Floor Lusby, Maryland 20657 1 1

__ - - - - - . . . _ . .. . . - .~ _-- - ._ _ _ .

• I

\v Distribution: MARD COPY Docket Files PUBLIC PDLR R/F MEl-Zeftawy DISTRIBUTION: E-MAIL: FMiraglia (FJM) JRoe (JWR) DMatthews (DBM) CGrimes (CIG) TEssig (THE) Glainas (GCL) JStrosnider (JRS2) GHolahan (GMH) SNewberry (SFN) GBagchi(GXB1) RRothman (RLR) JBrammer (HLB) CGratton (CXG1) JMoore (JEM) MZobler/RWeisman (MLZ/RMW) SBajwa/ADromerick (SSB1/AXD) LDoerflein (LTD) BBores (RJB) SDroggitis (SCD) RArchitzel (REA) CCraig (CMC 1) LSpessard (RLS) RCorreia (RPC) RLatta (RML1) EHackett (EMH1) AMurphy (AJM1) TMartin (TOM 2) DMartin (DAM 3) GMeyer (GWM) WMcDowell(WDM) SStewart (JSS1) THiltz (TGH) SDroggitis (SCD) DSolorio (DLS2) PDLR Staff JFair (JRF) KParczewski (KIP) SLittle (SLL)

    =
   'a REQUEST FOR ADDITIONAL INFORMATION CALVERT CLIFFS UNITS 1 AND 2 FEEDWATER SYSTEM INTEGRATED PLANT 6

DOCKET NOS. 50-317/50-318 Aging Management

1. The BGE application indicates that thermal stratification is a significant contributor to fatigue usage for the steam generator nozzle and adjacent piping. The application further indicates that the piping adjacent to the Unit 2 steam generator was instrumented with thermocouples to obtain temperature data around the circumference of the pipe.

Provide a sketch of the piping showing the locations of the thermocouples used to measure the temperature data for the steam generator nozzle.

2. The application indicates that the effect of local thermal stratification in the feedwater system does not extend beyond the first elbow of the vertical pipe run. Provide the basis for this conclusion.

3. The application indicates that a finite element analysis of the steam generator nozzle region was performed to determine the most critical location for fatigue. Provide the following information regarding the finite element analysis:

(a) Indicate the computer code used for the analysis. Describe the method used to verify the computer code. (b) Provide a description of the model used for the analysis and indicate the assumptions used in the analysis. Includs a discussion of stress intensification factors, if any, used in the analysis.

4. The application indicates that the critical feedwater nozzle welds in Unit 1 were inspected in 1996, and that no flaws with sizes above the critical flaw size specified in the ASME Code were identified. Characterize the indications, if any, that were identified during the inspections. The application also indicates that Unit 2 welds were scheduled for inspection during the 1997 refueling ou+ age. Provide the results of the Unit 2 inspections including a characterization of any indications identified during the inspections.

5. Electric Power Research Institute (EPRI) Report TR-107515, " Evaluation of Thermal Fatigue Effects on Systems Requiring Aging Management Review for License Renewal for the Calvert Cliffs Nuclear Power Plant," provides the retuits of the fatigue analyses of the feedwater nozzles. Table 3-16 of the EPRI report ladicates that fatigue usage factors, without considering environmental effsets, will exceed 1.0 prior to forty years of operation for two Unit 2 steam generator nozzles . Section 3.1.4 of the EPRI report contains a flaw tolerance evaluation in accordance with criteria in ASME Section XI Nonmandatory Appendix L. The flaw tolerance evaluation, using the environmental Enclosure m _ _ _ _ _

2 crack growth data in proposed ASME Code Case, " Fatigue Crack Growth Rate Curves for Ferritic Steels in PWR Water Environments," (Rev 1,12/10/96), Indicates that a postulated fatigue flaw in three of the steam generator feedwater nozzles could grow through wail in less than one operating cycle. The BGE license renewal application

indicates that corrective actions will be initiated wellin advance of reaching a fatigue usage factor of 1.0. Describe the corrective actions that will be initiated when the fatigue usage factor approaches 1.0 at the steam generator feedwater nozzles.

6. Section 5.9 of the application references a site report (Reference 33 on page 5.9-26 of the application) dated July,1996, for the BGE fatigue evaluation. Other sections of the application reference this report or other apparently similar reports. In December,1997, EPRI issued Report TR-107515, ' Evaluation of Thermal Fatigue Effects on Systems Requiring Aging Management Review for License Renewal for the Calvert Cliffs Nuclear Power Plant." By letter dated February 9,1998, EPRI submitted this report for staff i information. Describe the extent to which EPRI Report TR-107515 is a current fatigue l evaluation and the results of all of the other plant-specific fatigue analyses.

i

7. BGE's program for managing the effects of erosion / corrosion is to monitor the local pipe 4

wall thickness and take corrective action when the wall thickness is projected to fall below a certain minimum value. Your July 30,1998, response to the staff request for additional information (RAl) on the feedwater system, question 13, indicates that this minimum wall thickness is determined based on internal pressure alone. (a) Please demonstrate that piping with a pipe wall thinned locally to this minimum wall thickness could withstand all licensing basis loads, including bending. (b) The minimum wall thickness equation cited in your July 30,1998, RAI response applies only to straight pipes. Please provide the basis for applying this equation to fittings, such as elbows, tees, reducers, and fabricated branch connections.

8. One of the most effective ways of minimizing erosion / corrosion is to control secondary water chemistry, that is, pH and oxygen concentration. Describe whether pH and oxygen concentration are controlled in the feedwater system and if so, specify the parameter ranges.

9. In order to measure the maximum wall thinning of a given component caused by erosion / corrosion, several measurements at different locations are made and the maximum wall thinning is calculated. Describe what approach is used for measuring data along a pipe (that is, band, area, moving blanket, or point to point method).

10. Describe the erosion / corrosion degradation of the feedwater check valves which was discovered during their inspection at the Calvert Cliffs plants. How was the inspection performed? Was the wall thinning measured or was the inspection limited only to visual examination?

11. In addition to the predictions by the CHECWORKS computer code, what other selection methods (for example, industry experience and engineering judgment) are used in

 -. .         - . . - -             .  - - _ _ ~ _             . . . - . - .      -          - . . --     . -.   - . - . .

a 3 selecting components for erosion / corrosion inspection (wall thickness measurement)? Describe them briefly.

12. To determine the life of the components exposed to erosion / corrosion, it is important to know the rate at which thinning of their walls is occurring. This information can be obtained by using appropriate methods for trending component degradation due to erosion / corrosion. Describe the trending methods used in predicting life of the components. In your trending methods, are you using measured or computer predicted data?

13. What is the frequency of valve inspection in the Preventive Maintenance Program relied on to manage erosion / corrosion?

14. Describe the materials for replacement components in the feedwater system due to erosion / corrosion degradation, such as enromium-molybdenum and carbon steel.

15. Page 5.9-20 of the application indicates that the Institute of Nuclear Power Operations (INPO) has performed assessment of the BGE erosion / corrosion program and provided recommendation for enhancoments. Please briefly summarize the results of the INPO assessment and outline the INPO recommendations for improvements at the Calvert Cliffs plants.

16. Describe incid6nts of damage or failure of components caused by erosion / corrosion at Calvert Cliffs and associated corrective actions.

17. Does the BGE erosion / corrosion program permit weld overlay as a corrective action when degraded components are found?

18. Describe the extent of inspection of 2-inch and less piping as part of the BGE ,

erosion / corrosion program. L 5 6 s

                                                                                                                           >}}