ML16141A988
| ML16141A988 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Mcguire, Catawba, McGuire  |
| Issue date: | 12/27/1995 |
| From: | Abramson P, Komoriya H INTERNATIONAL TECHNICAL SERVICES, INC. |
| To: | NRC |
| Shared Package | |
| ML16141A987 | List: |
| References | |
| CON-FIN-L-1318, CON-NRC-03-90-027, CON-NRC-3-90-27 ITS-NRC-95-4, NUDOCS 9601020074 | |
| Download: ML16141A988 (4) | |
Text
ITS/NRC/95-4 TECHNICAL EVALUATION:
THERMAL-HYDRAULIC TRANSIENT ANALYSIS METHODOLOGY DPC-NE-3000 REVISION 3 FOR DUKE POWER COMPANY P.B. Abramson H. Komoriya Prepared for U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Under NRC Contract No. NRC-03-90-027 FIN No. L1318 International Technical Services, Inc.
420 Lexington Avenue New York, NY 10170 9601020074 951227 PDR ADOCK 05000269 P
ITS/NRC/95-4 TECHNICAL EVALUATION OF THE THERMAL-HYDRAULIC TRANSIENT ANALYSIS METHODOLOGY TOPICAL REPORT DPC-NE-3000 REVISION 3 FOR THE DUKE POWER COMPANY OCONEE, MCGUIRE AND CATAWBA NUCLEAR STATIONS
1.0 INTRODUCTION
In Revision 3 of the topical report entitled "Thermal-Hydraulic Transient Analysis Methodology,"
DPC-NE-3000, dated July 1994 (Ref.
1),
Duke Power COmpany (DPC) documents revisions to the currently approved thermal-hydraulic transient analysis methodology for Oconee, McGuire and Catawba stations (Ref.
2).
The revisions reflect changes due to the proposed replacement of steam generators for the McGuire and Catawba Unit 1 stations and methodology changes.
Corrections of typographical errors are also included. Additional' information was provided in Reference 3.
The currently approved methodology (Ref. 2) for non-LOCA transient safety analysis is based upon the use of the RETRAN-02 and VIPRE-01 computer codes for McGuire, Catawba and Oconee stations.
In Revision 3, only the RETRAN portion of the methodology was revised. The stated objective of the subject revision of the topical report is for DPC to demonstrate acceptability of changes in the analysis methodology for Oconee, McGuire and Catawba plants.
This review is focused upon determining acceptability of the revised RETRAN plant models and their impact on previously approved analysis.
2.0
SUMMARY
DPC incorporated, in Revision 3 of DPC-NE-3000, new sections describing B&W's feedring steam generator (FSG),
which is expected to replace the existing Westinghouse preheater steam generators (PSG) at the McGuire and Catawba Unit I nuclear stations. Necessary modifications to associated components such as steam line and feedwater lines were also made.
There are minor modifications to the RETRAN methodology including the treatment of phase separation in some volumes and pressurizer modeling.
Setpoints changes were incorporated into the description of the respective components and control systems. A description of the General Transport model to simulate boron transport (its use was approved in connection with the steam line break analysis in DPC-NE-3001 (Ref.
4))
was also added to the report for completeness.
In addition, DPC corrected numerous typographical errors and made some editorial changes which are of no technical significance.
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3.0 EVALUATION Revisions incorporated into the submittal can be categorized into three classes:
(1) modeling upgrades and incorporation of a new steam generator model; (2) setpoint changes due to revised Technical Specifications; (3) non technical correction to the text. Revisions to the approved RETRAN transient analysis methodology and their acceptability are discussed. Minor changes of a non-technical nature are not discussed, since these changes have no technical impact and are acceptable.
3.1 Revisions to RETRAN Models These model revisions resulted from consolidation of modifications made due to (i) proposed steam generator replacements, (ii) better und'erstanding gained through sensitivity studies performed since the original review, and (iii) plant technical specification changes.
3.1.1 Editorial Changes The RETRAN General Transport model is used to simulate boron transport in the steam line break analysis.
The model description is added to the topical report for completeness.
The use of this model for steam line break was reviewed and approved in DPC-NE-3001.
3.1.2 Setpoint Changes There are many setpoint changes used in the RETRAN control systems documented in this revision due to revised Technical Specifications.
DPC will use NRC approved setpoints.
3.1.3 Revised RETRAN Plant Models Modeling upgrades were made in the (1) pressurizer model, (2) two-phase
- modeling, and (3) Feedring SG model.
The addition of the Feedring SG model and changes necessitated in associated components were also presented in this revision.
3.2 Description and Qualification of Revised Models Pressurizer Model The pressurizer vessel model was modified to include heat conductors using the local conditions heat transfer model.
The pressurizer level is computed in the RETRAN control system whose modeling simulates the actual plant function.
Phase Separation The bubble-rise model was used to simulate the two-phase separation in components where two-phase liquid is expected. The bubble rise velocity and gradient are specified. This option is specified instead of the HEM option 2
in the primary system volumes stated in the Revision. As long as the primary system remains subcooled, the option is not activated. However, in the event that subcooling is lost, with the exception of the pressurizer, DPC should justify that its use is appropriate and results in conservative predictions.
Steam Generator Replacement The description of the B&W Feedring Steam Generator (FSG) is provided.
Due to the design differences, the FSG nodalization is slightly different from the pre-heater SG nodalization.
Although there is no transient data to qualify the adequacy of the nodalization, DPC provided comparison of RETRAN computed SG mass and level with the vendor computed data and obtained good agreement. Similarly, DPC provided comparison of RETRAN computed RCS hot and cold leg temperatures given a specified RCS flow and steam line pressure with the vendor predictions.
Comparison indicated that the heat transfer of the FSG was predicted well with the RETRAN model.
Based upon these comparisons, it was concluded that the feedring SG nodalization and model is acceptable.
4.0 CONCLUSION
S DPC topical report DPC-NE-3000 Revision 3 and the DPC responses to NRC questions were reviewed.
DPC's revised RETRAN models for the McGuire/Catawba and Oconee nuclear power plants are acceptable in application to non-LOCA transient and safety analysis.
Acceptability of the use of the proposed revisions in non-LOCA transient safety licensing analysis remains subject to the limitations set forth in the SERs on DPC-NE-3001 and 3002 (Ref. 5).
Furthermore, acceptability does not remove limitations and restriction set forth in the SER on the original DPC NE-3000 for those issues not impacted by the subject revision.
5.0 REFERENCES
- 2. "Thermal-Hydraulic Transient Analysis Methodology,"
DPC-NE-3000, July 1981.
- 3. Letter from M.S. Tuckman (DPC) to USNRC, "Request for Additional Information Relative to DPC-NE-3000P, Revision 1;
Responses to Questions," September 12, 1995.
- 4. "Duke Power Company Multidimensional Reactor Transients and Safety Analysis Physics Parameters Methodology," DPC-NE-3001-P, January 1990.
- 5.
"FSAR Chapter 15 System Transient Analysis Methodology,"
DPC-NE-3002, Revision 1, November 1994.
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