Similar Documents at Maine Yankee |
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Category:SAFETY EVALUATION REPORT--LICENSING & RELATED ISSUES
MONTHYEARML20196K4821999-07-0606 July 1999 Safety Evaluation Concluding That Because of Permanently Shutdown & Defueled Status of Myaps Facility,Confirmatory Orders No Longer Necessary for Safe Operation or Maint of Plant ML20206H1611999-05-0505 May 1999 Safety Evaluation Supporting Amend 164 to License DPR-36 ML20206G5731999-05-0303 May 1999 Safety Evaluation Supporting Amend 163 to License DPR-36 ML20205D5261999-03-26026 March 1999 SER Accepting Util Rev 1 to CFH Training & Retraining Program for Maine Yankee.Rev 1 to CFH Training & Retraining Program Consistent with Current Licensing Practice for Facilities Undergoing Decommissioning ML20204C4631999-03-16016 March 1999 Safety Evaluation Supporting Amend 162 to License DPR-36 ML20197C8231998-09-0303 September 1998 Safety Evaluation Supporting Request for Exemption from Certain Requirements of 10CFR50.54(q),10CFR50.47(b) & (C) & App E to 10CFR50 Re Emergency Planning ML20236U8451998-07-24024 July 1998 Safety Evaluation Accepting Rev 14 to Maine Yankee Atomic Power Co Operational QA Program ML20217H5241998-03-30030 March 1998 Safety Evaluation Supporting Amend 161 to License DPR-36 ML20202D3181997-11-26026 November 1997 Safety Evaluation Supporting Amend 160 to License DPR-36 ML20216F1511997-08-0808 August 1997 Safety Evaluation Supporting Amend 159 to License DPR-36 ML20141G6511997-05-19019 May 1997 Safety Evaluation Supporting Amend 158 to License DPR-36 ML20138G3541997-05-0202 May 1997 Safety Evaluation Supporting Amend 157 to License DPR-36 ML20058E2641993-11-0505 November 1993 Safety Evaluation Supporting Amend 143 to License DPR-36 ML20056F7831993-08-23023 August 1993 Safety Evaluation Supporting Amend 142 to License DPR-36 ML20127D5061993-01-11011 January 1993 Safety Evaluation Supporting Amend 136 to License DPR-36 ML20126H6211992-12-29029 December 1992 Safety Evaluation Supporting Amend 135 to License DPR-36 ML20059K9991990-09-20020 September 1990 SER Accepting Methodology Re Statistical Combination of Uncertainties for RPS Setpoints ML20059H5901990-09-12012 September 1990 Safety Evaluation Re Facility Response to Station Blackout Rule.Issue of Conformance to Station Blackout Rule Will Remain Open at Facility Until Identified Nonconformances Resolved ML20059D0501990-08-30030 August 1990 Safety Evaluation Supporting Amend 117 to License DPR-36 ML20055C2911990-02-20020 February 1990 Safety Evaluation Accepting Util Assessment of Asymmetric LOCA Loads Problem ML20246F6281989-07-10010 July 1989 Safety Evaluation Supporting Amend 113 to License DPR-36 ML20245J0571989-04-25025 April 1989 SER Re Accepting Facility Emergency Response Capability in Conformance to Reg Guide 1.97,Rev 3,w/exception of Instrumentation Re Variables Accumulator Tank Level & Pressure & Containment Sump Water Temp ML20245D4481989-04-24024 April 1989 Safety Evaluation Supporting Amend 111 to License DPR-36 ML20245D4351989-04-24024 April 1989 Safety Evaluation Supporting Amend 112 to License DPR-36 ML20155B4631988-09-27027 September 1988 Safety Evaluation Supporting Amend 107 to License DPR-36 ML20154A1411988-09-0707 September 1988 Safety Evaluation Supporting Amend 106 to License DPR-36 ML20150D7681988-07-0707 July 1988 Safety Evaluation Approving Util Inadequate Core Cooling Instrumentation Sys Contingent on Completion of Emergency Procedures & Operator Training & Submittal of Applicable Tech Specs ML20153A9641988-06-28028 June 1988 Safety Evaluation Accepting Util Proposed Reflood Steam Cooling Model ML20196G6871988-06-23023 June 1988 Safety Evaluation Supporting Amend 105 to License DPR-36 ML20151W5861988-04-26026 April 1988 Safety Evaluation Supporting Amend 104 to License DPR-36 ML20153B3381988-03-16016 March 1988 Safety Evaluation Supporting Util 831110,840216,0412,1214, 850618 & 0820 Responses to Generic Ltr 83-28,Item 2.2.2, Based on Stated Util Commitments,Insp Rept 50-309/86-07 & Actions Described in Procedure for Vendor Interface ML20149H2831988-02-17017 February 1988 Safety Evaluation Supporting Amend 103 to License DPR-36 ML20196C4301988-02-0909 February 1988 Safety Evaluation Supporting Amend 102 to License DPR-36 ML20235M4661987-09-29029 September 1987 Safety Evaluation Supporting Amend 101 to License DPR-36 ML20236F6441987-07-29029 July 1987 Safety Evaluation Supporting Util Response to Item 2.1 of Generic Ltr 83-28 ML20234B1781987-06-25025 June 1987 Safety Evaluation Supporting Amend 100 to License DPR-36 ML20216J0371987-06-25025 June 1987 Safety Evaluation Supporting Amend 99 to License DPR-36 ML20215E9301987-06-15015 June 1987 Safety Evaluation Supporting Amend 98 to License DPR-36 ML20214W3841987-06-0404 June 1987 SER Supporting Util 831110 Response to Generic Ltr 83-28, Item 2.2 (Part 1) Re Requirement for Program Description to Ensure All Components of safety-related Sys Identified as safety-related on Informational Matls ML20214M1491987-05-21021 May 1987 Safety Evaluation Supporting Util Responses to Generic Ltr 83-28,Item 2.1 (Part 2) Re Established Interface W/Nsss or Vendors of Each Component of Reactor Trip Sys ML20214J6001987-05-20020 May 1987 Safety Evaluation Supporting Amend 97 to License DPR-36 ML20210C6631987-04-23023 April 1987 Safety Evaluation Re Adequacy of Offsite Power Sys.Further Evaluation Cannot Continue Until All Requested Info Received.Surowiec Line Not Acceptable Substitute for Mason Line During Startup or Normal Operations ML20206U9231987-04-0909 April 1987 Safety Evaluation Supporting Amend 96 to License DPR-36 ML20197D4421987-04-0707 April 1987 Safety Evaluation Supporting 850807 Request for Relief from ASME Code,Section XI Inservice Testing Requirements for Pump & Valves ML20205M6391987-03-26026 March 1987 Safety Evaluation Accepting Upgraded Seismic Design Program Contingent on Licensee Commitment to Upgrade Items in Table 3 ML20197D4241987-03-26026 March 1987 Safety Evaluation Supporting Amend 94 to License DPR-36 ML20212N7091987-03-0404 March 1987 Safety Evaluation Supporting Amend 93 to License DPR-36 ML20211G4361987-02-14014 February 1987 Safety Evaluation Supporting Util 831110 Response to Generic Ltr 83-28,Item 4.5.2 Re on-line Testing for Reactor Trip Sys Reliability ML20210V1831987-02-0909 February 1987 Safety Evaluation Supporting Amend 92 to License DPR-36 ML20207N2181987-01-12012 January 1987 Safety Evaluation Supporting Util Response to NRC 860721 Request for Addl Info Re Reactor Coolant Pump Shaft Integrity,Per IE Info Notice 86-019 1999-07-06
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20211M4841999-08-31031 August 1999 Replacement Pages 2-48,2-49 & 2-50 to Rev 14 of Defueled Sar ML20211D7111999-08-0909 August 1999 Rev 17 to Maine Yankee Defueled Safety Analysis Rept (Dsar) ML20196K4821999-07-0606 July 1999 Safety Evaluation Concluding That Because of Permanently Shutdown & Defueled Status of Myaps Facility,Confirmatory Orders No Longer Necessary for Safe Operation or Maint of Plant ML20206H1611999-05-0505 May 1999 Safety Evaluation Supporting Amend 164 to License DPR-36 ML20206G5731999-05-0303 May 1999 Safety Evaluation Supporting Amend 163 to License DPR-36 ML20205D5261999-03-26026 March 1999 SER Accepting Util Rev 1 to CFH Training & Retraining Program for Maine Yankee.Rev 1 to CFH Training & Retraining Program Consistent with Current Licensing Practice for Facilities Undergoing Decommissioning ML20204C4631999-03-16016 March 1999 Safety Evaluation Supporting Amend 162 to License DPR-36 ML20206D7491998-12-31031 December 1998 Co Annual Financial Rept for 1998. with ML20155G9591998-11-0303 November 1998 Rev 1 to Post-Shutdown Decommissioning Activities Rept ML20155D8651998-10-28028 October 1998 Public Version of, Maine Yankee Emergency Preparedness Exercise ML20197C8231998-09-0303 September 1998 Safety Evaluation Supporting Request for Exemption from Certain Requirements of 10CFR50.54(q),10CFR50.47(b) & (C) & App E to 10CFR50 Re Emergency Planning ML18066A2771998-08-13013 August 1998 Part 21 Rept Re Deficiency in CE Current Screening Methodology for Determining Limiting Fuel Assembly for Detailed PWR thermal-hydraulic Sa.Evaluations Were Performed for Affected Plants to Determine Effect of Deficiency ML20236X1751998-08-0303 August 1998 Rev 16 to Defueled Sar ML20236U8451998-07-24024 July 1998 Safety Evaluation Accepting Rev 14 to Maine Yankee Atomic Power Co Operational QA Program ML20248D3011998-05-26026 May 1998 Rev 14,page 16 of 17,Section II of QA Program ML20247J0211998-05-11011 May 1998 Revised Page 16 of 17 of Section II of QA Program,Rev 14 ML20247D3451998-05-0606 May 1998 Rev 15 to Defueled SAR, Replacing List of Effective Pages ML20217J9811998-04-28028 April 1998 Part 21 Rept Re Incorrect Description of Drift Specification for Model 1154,gauge Pressure Transmitters,Range Code 0 in Manual Man 4514,Dec 1992.Cause Indeterminate.Will Issue & Include Errata Sheets in All Future Shipments to Users ML20217H5241998-03-30030 March 1998 Safety Evaluation Supporting Amend 161 to License DPR-36 ML20217D9691998-02-28028 February 1998 Monthly Operating Rept for Feb 1998 for Maine Yankee.W/ ML20216D7681998-02-25025 February 1998 Rept to Duke Engineering & Services,Inc,On Allegations of Willfulness Related to Us NRC 971219 Demand for Info ML20203A3011998-01-31031 January 1998 Monthly Operating Rept for Jan 1998 for Maine Yankee ML20202F3771998-01-31031 January 1998 Annual Rept of Facility Changes & Relief & Safety Valve Failures & Challenges ML20202E0541998-01-30030 January 1998 Rev 14 to Myaps Defueled Safety Analysis Rept ML20199K3211998-01-27027 January 1998 Rev 13 to Maine Yankee Atomic Power Co,Qa Program ML20199K3471998-01-22022 January 1998 Rev 14 to Maine Yankee Atomic Power Co QA Program ML20199C2281997-12-31031 December 1997 Monthly Operating Rept for Dec 1997 for Maine Yankee ML20217R2301997-12-31031 December 1997 Myap Annual Financial Rept for 1997 ML20203F8551997-11-30030 November 1997 Monthly Operating Rept for Nov 1997 for Maine Yankee ML20202D3181997-11-26026 November 1997 Safety Evaluation Supporting Amend 160 to License DPR-36 ML20198R6371997-11-0606 November 1997 Yankee Mutual Assistance Agreement ML20155G9511997-10-31031 October 1997 Rev 1 to M01-1258-002, Decommissioning Cost Analysis for Myaps ML20198P9431997-10-31031 October 1997 Monthly Operating Rept for Oct 1997 for Maine Yankee ML20217K5191997-10-24024 October 1997 Part 21 Rept Re Five Valves That May Have Defect Related to Possible Crack within Forging Wall at Die Flash Line.Caused by Less than Optimal Forging Temperatures.Newer Temperature Monitoring Devices at Forging Area Heating Ovens Procured ML20211N0571997-10-0707 October 1997 Revised Pages to Jul/Aug 1994 SG Insp Summary Rept ML20198K0201997-09-30030 September 1997 Monthly Operating Rept for Sept 1997 for Maine Yankee ML20199H1861997-09-25025 September 1997 Rev 12 to Maine Yankee Atomic Power Co,Qa Program ML20217A9251997-08-31031 August 1997 Monthly Operating Rept for Aug 1997 for Maine Yankee ML20217R1051997-08-27027 August 1997 Myaps Post Shutdown Decommissioning Activities Rept ML20216F1511997-08-0808 August 1997 Safety Evaluation Supporting Amend 159 to License DPR-36 ML20210M4451997-07-31031 July 1997 Monthly Operating Rept for July 1997 for Myaps ML20151M1351997-07-21021 July 1997 Rev 0 to Technical Evaluation 172-97, Cable Separation Safety Assessment Rept ML20141H2691997-06-30030 June 1997 Monthly Operating Rept for June 1997 for Maine Yankee ML20141B9951997-05-31031 May 1997 Monthly Operating Rept for May 1997 for Maine Yankee.W/ ML20141G6511997-05-19019 May 1997 Safety Evaluation Supporting Amend 158 to License DPR-36 ML20138G3541997-05-0202 May 1997 Safety Evaluation Supporting Amend 157 to License DPR-36 ML20141G2871997-04-30030 April 1997 Monthly Operating Rept for Apr 1997 for Maine Yankee ML20137Z1971997-04-14014 April 1997 Forwards to Commission Results of Staff Evaluation of Performance of Licensees W/Ownership Structure Similar to Plant ML20137N7541997-03-31031 March 1997 Rev 11 to Operational Quality Assurance Program ML20138B1491997-03-31031 March 1997 Monthly Operating Rept for Mar 1997 for Maine Yankee 1999-08-09
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ENCLOSURE SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO REFLOOD STEAM COOLING MODEL MAINE YANKEE ATOMIC POWER COMPANY DOCKET NO. 50-309
1.0 INTRODUCTION
In a letter from G. Whittier to V. Nerses, (USNRC), da.ed May 21, 1987, Maine Yankee Atomic Power Company (MYAPCo) provided analyses 'or a proposed revised steam cooling model. The steam cooling model is to be ed to calculate heat transfer during the reflood phase of a loss-of-Coolant-Ai cident (LOCA) for Maine Yankee Nuclear Plant. By a January 5, 1988 letter from G. Papanic to M.
Fairtile (USNRC), Yankee Atomic Electric Company (YAECo) also submitted analyses for a revised steam cooling model for Yankee Rowe Nuclear Plant.
Because the proposals by both licensees are identical, and because the current Maine Yankee and Yankee Rowe steam cooling models for LOCA are virtually identical, this evaluation applies to both referenced proposals.
According to Appendix K of 10CFR50, Section I.D.5, heat transfer must be assumed to be accomplished via cooling by steam only when reflood rates in the core fall below one inch per second. Also, flow blockage must be considered in the steam cooling model in terms of both heat transfer and steam flow. Currently, both MYAPCo and YAEco steam cooling models exemplify and u:e these two characteristic requirements conservatively. With the pr:psed modifications, additional heat transfer capability would be credited in the LOCA analyses, thereby lessening the conservativeness of the current stam cooling model.
As it stands now, the steam cooling model is basically a correlation based on FLECHT test data. A penalty is incorporated in the model, in accordance with Appendix K, to account for the effect of flow chanr.31 blockage. As proposed, the steam cooling model modification would take c' dit for some enhancement in heat transfer as reflected in the more recent tes data. The proposed model would, however, continue to include the specific .onservatisms required by Appendix K. Thus, although the proposal would eliminate excessive conservatism, sufficient conservatism in the model would remain.
2.0 EVALUATION Analyses by MYAPCo and YAEco were done with a wide range of test data.
Included were FLECHT-SEASET data results which showed heat transfer enhancement. The staff notes that the tests were conducted for both blocked and unblocked test assemblies, for densely rodded assembly and sparsely rodded assembly configurations, and with and without bypass flow. Heat transfer was consistently found +,o be enhanced during low reflood rates. Sensitivity studies performed by the licensees were also consistent with these findings.
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Two effects are believed by the licensees to contribute to the overall heat transfer enhancement demonstrated by the test results and by the COBRA-TF computer program results. They are droplet breakup and single phase turbulence. The assumed presence of droplets, however, would violate the Aopendix K requirement that cooling may only be assumed by steam. Single phase (gaseous) turbulence downstream of the blockage is therefore considered by the licensees to be the main contributor for the heat transfer enhancement seen in the more recent test data.
Evaluations were performed by the licensees using various experiments to deduce relationships representing the effects of turbulent steam flow behavior. The relationships represented the. effects in terms of Nusselt numbers and showed an exponential decrease in heat transfer enhancement as distance from the blockage increased. The resultant modification to the model was benchmarked and compared to experimental and test results, and were found to be in good agreement.
We are not convinced that the proposed model truly represents the flow regime downstream of the blockage; the physical basis given for the heat transfer enhancement is questionable. However, the staff recognizes that the Appendix K steam cooling model requirements were administered due to a lack of experimental data at low flooding rate. Data generated since the development of Appendix K has demonstrated that reflood heat transfer characteristics at low reflooding rates (less than one inch per second) are similar to heat transfer characteristics at reflooding rates greater than one inch per second. Thus, staff practice is to assure that steam cooling models developed by licensees meet the specific requirements of Appendix K, i.e., effect on flow diversion, while conservatively predicting heat transfer observed in the experimental data. Regardless of the physical interpretation applied to the model, the proposed model was shown to conservatively predict the recent experimental data in accordance with 10 CFR Part b], Appendix K. No change in the flow divergence model would result from the incorporation of the proposed nodel . Therefore, we find the proposed modification to be acceptable.
3.0 CONCLUSION
S Analyses of test data by the licensees show an overall heat transfer
- enhancement for reflood rotes less than one inch per second. The licensees have incorporated a modi #ication to their steam cooling model which better predicts this increased heat transfer as demonstrated in the more recently accumulated reflood heat transfer data. Although the physical interpretation of the additional enhancement is unclear, the model as proposed was demonstrated to be conservative with respect to FLECHT results. Since the model complies with the requirements of Section I.D.S of Appendix K of 10CFR50, we find the proposed steam cooling model revision acceptable.
4.0 REFERENCES
- 1. Letter frcm G. Papanic, Jr. (Yankee Atomic Electric Co.) to M. Fairtile (NRC), dated January 5, 1988.
- 2. Letter from G. Whittier (Maine Yankee Atomic Power Co.) to V. Nerses (NRC), dated May 21, 1987.
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- 3. Letter from G. Whittier (MYAPCo) to A. Thadani (NRC), dated Navember 10, 1986.
- 4. Letter from D. Crutchfield (NRC) to G. Ward (Exxon Nuclear Co.), dated July 8, 1986. !
- 5. Letter from R. Groce (MYAPCo) to NRR (NRC), dated January 15, 1979.
- 6. "Application of Yankee-WREM-BASED Generic PWR ECCS Evaluation Model to Maine Yankee," YAEC-116, dated July 1979.
- 7. L. E. Hochreiter, "FLECHT-SEASET Program Final Report,"
NRC/EPRI/ Westinghouse-16, dated November 1985.
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