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Category:SAFETY EVALUATION REPORT--LICENSING & RELATED ISSUES
MONTHYEARML20211N0511999-09-0303 September 1999 SER Approving Exemption from Certain Requirements of 10CFR50.44 & 10CFR50 App A,General Design Criterion 41 to Remove Requirements from Hydrogen Control Systems from SONGS Units 2 & 3 Design Basis ML20211H8621999-08-23023 August 1999 Safety Evaluation Accepting Licensee Requests for Relief RR-E-2-03 - RR-E-2-08 from Exam Requirements of Applicable ASME Code,Section Xi,For First Containment ISI Interval ML20205Q6221999-04-19019 April 1999 Safety Evaluation Authorizing Proposed Alternative to Use Wire Penetrameters for ISI Radiography in Place of ASME Code Requirement ML20205R0371999-04-16016 April 1999 SER Approving Proposed Deviation from Approved Fire Protection Program Incorporating Technical Requirements of 10CFR50,App R,Section III.0 That Applies to RCP Oil Fill Piping ML20203J1981999-02-12012 February 1999 Safety Evaluation Supporting Amends 149 & 141 to Licenses NPF-10 & NPF-15,respectively ML20154B7211998-10-0101 October 1998 Safety Evaluation Approving Licensee Request to Implement Alternatives Contained in Code Case N-546 for Current Interval at Songs,Units 2 & 3 Until Code Case Approved by Ref in Reg Guide 1.147 ML20203E7301998-02-17017 February 1998 SER Accepting 980105 Request to Use Mechanical Nozzle Seal Assembly as Alternate Repair Method,Per 10CFR50.55a(a)(3)(1) for Plant,Units 2 & 3 ML20210T0631997-08-29029 August 1997 Safety Evaluation Approving Application Re Proposed Restructuring of Enova Corp,Parent Company of San Diego Gas & Electric Co by Establishment of Holding Company W/Pacific Enterprises ML20128L7231996-10-0303 October 1996 Safety Evaluation Supporting Amend 158 to License DPR-13 ML20058B1241993-11-19019 November 1993 Safety Evaluation Accepting Proposal to Leak Rate Test SI Tank Outlet Check Valves by Using Leak Test Method Described in OM-10,Paragraph 4.2.2.3(c) ML20057G3071993-10-18018 October 1993 Safety Evaluation Granting Licensee 930616 Relief Request B-12 Re Hydrostatic Testing of Certain Welds in 4 Inch Line from Main Steam Header to Auxiliary Feedwater Pump ML20056E0851993-08-0202 August 1993 Safety Evaluation Accepting Licensee 890308,910301 & 911217 Responses to NRC Bulletin 88-011 Re C-E Owners Group Program for Evaluation of Pressurizer Surge Line Thermal Stratification ML20056D6421993-07-27027 July 1993 SER Approving Licensee 930305 Relief Requests B-10,B-11 & Code Case N-496 ML20128P8401993-02-17017 February 1993 Safety Evaluation Supporting Amend 153 to License DPR-13 ML20125A4341992-12-0303 December 1992 Safety Evaluation Accepting Alternative Exam Methods Per 10CFR50.55a(a)(3)(i) & Addl Info Re Auxiliary Feedwater Sys Lube Oil Cooling,Per ISI Relief Requests B-7,B-8 & B-9 & Code Case N-481 ML20055E3041988-02-12012 February 1988 Safety Evaluation Supporting Util 871223 & 880111 Proposed Changes to Tech Specs,Including Reducing Lower Limits of Detection for Liquid Radioactive Effluents ML20209H9551987-01-28028 January 1987 SER Re Tdi Diesel Generator Owners Group Findings & Recommendations for Operabilty/Reliabilty of Tdi Emergency Diesel Generators ML20214E4231986-11-19019 November 1986 SER Re Reliability & Operability of Tdi Diesel Engines as Source for Emergency Power.Engines Will Continue to Provide Reliable Svc Until Next Refueling Outage ML20195C8261986-05-16016 May 1986 Safety Evaluation Supporting Amends 47 & 36 to Licenses NPF-10 & NPF-15,respectively ML20207K2701985-11-22022 November 1985 Safety Evaluation Supporting Amends 38 & 27 to Licenses NPF-10 & NPF-15,respectively ML20138B0281985-09-25025 September 1985 Safety Evaluation Supporting Amends 35 & 24 to Licenses NPF-10 & NPF-15,respectively ML20126H0781984-11-30030 November 1984 Draft SER Supporting Return to Svc ML20136H1121982-08-31031 August 1982 Sser Supporting Fire Protection ML20136H0761981-02-0404 February 1981 Marked-up Sser 1 Supporting Fire Protection ML20136E0781981-01-19019 January 1981 Safety Evaluation Supporting Fire Protection Program, Providing Mods Are Made Before Fuel Loading ML20136D9691980-11-11011 November 1980 Safety Evaluation Re Fire Protection Sys.Licensee Proposed Mods Acceptable ML20148C4901978-10-16016 October 1978 Safety Evaluation Supporting Postponement of Permanent ECCS Single Failure Fixes at Facility.Postponement of Installation of Redundant Undervoltage Relays Unacceptable 1999-09-03
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217E3381999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Songs,Units 2 & 3 ML20212A1471999-09-13013 September 1999 Special Rept:On 990904,condenser Monitor Was Declared Inoperable.Difficulties Encountered During Component Replacement Precluded SCE from Restoring Monitor to Service within 72 H.Alternate Method of Monitoring Was Established ML20211N0511999-09-0303 September 1999 SER Approving Exemption from Certain Requirements of 10CFR50.44 & 10CFR50 App A,General Design Criterion 41 to Remove Requirements from Hydrogen Control Systems from SONGS Units 2 & 3 Design Basis ML20211Q8201999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Songs,Units 2 & 3. with ML20211H8621999-08-23023 August 1999 Safety Evaluation Accepting Licensee Requests for Relief RR-E-2-03 - RR-E-2-08 from Exam Requirements of Applicable ASME Code,Section Xi,For First Containment ISI Interval ML20210P4791999-08-11011 August 1999 COLR Cycle 10 Songs,Unit 3 ML20210P4731999-08-11011 August 1999 COLR Cycle 10 Songs,Unit 2 ML20210Q6521999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Songs,Units 2 & 3 ML20210L2771999-07-30030 July 1999 SONGS Unit 3 ISI Summary Rept 2nd Interval,2nd Period Cycle 10 Refueling Outage U3C10 Site Technical Services ML20209C9281999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Songs,Units 2 & 3. with ML20195D3061999-06-0202 June 1999 Safety Evaluation of TR SCE-9801-P, Reload Analysis Methodology for San Onofre Nuclear Generating Station,Units 2 & 3. Rept Acceptable ML20195H5491999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Songs,Units 2 & 3 ML20196L3221999-05-11011 May 1999 SONGS Unit 2 ISI Summary Rept 2nd Interval,2nd Period Cycle-10 Refueling Outage ML20206H2611999-05-0505 May 1999 Part 21 Rept Re Defect Found in Potter & Brumfield Relays. Sixteen Relays Supplied in Lot 913501 by Vendor as Commercial Grade Items.Caused by Insufficient Contact Pad Welding.Relays Replaced with New Relays ML20206S7281999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Songs,Units 2 & 3 ML20205Q6221999-04-19019 April 1999 Safety Evaluation Authorizing Proposed Alternative to Use Wire Penetrameters for ISI Radiography in Place of ASME Code Requirement ML20205R0371999-04-16016 April 1999 SER Approving Proposed Deviation from Approved Fire Protection Program Incorporating Technical Requirements of 10CFR50,App R,Section III.0 That Applies to RCP Oil Fill Piping ML20205G2611999-04-0101 April 1999 Special Rept:On 990328,3RT-7865 Was Removed from Service. Monitor Is Scheduled to Be Returned to Service Prior to Mode 4 Entry (Early May 1999) Which Will Exceed 72 H Allowed by LCS 3.3.102.Alternate Method of Monitoring Will Be Used ML20205Q0981999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Songs,Units 2 & 3 ML20204F8101999-02-28028 February 1999 Monthly Operating Repts for Songs,Units 2 & 3.With ML20203J1981999-02-12012 February 1999 Safety Evaluation Supporting Amends 149 & 141 to Licenses NPF-10 & NPF-15,respectively ML20202F7041999-01-21021 January 1999 Special Rept:On 990106,SCE Began to Modify 2RT-7865.2RT-7865 to Allow Monitor to Provide Input to New Radiation Monitoring Data Acquisition Sys.Monitor Found to Exceeds 72 H Allowed Bt LCS 3.3.102.Alternate Monitoring Established ML20199F0771998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Songs,Units 2 & 3 ML20206H2101998-12-31031 December 1998 SCE 1998 Annual Rept ML20198A6731998-12-11011 December 1998 Special Rept:On 981124,meteorological Sys Wind Direction Sensor Was Observed to Be Inoperable.Caused by Loss of Communication from Tower to Cr.Sensor Was Replaced & Sys Was Declared Operable on 981204 ML20196D8901998-11-30030 November 1998 Non-proprietary Reload Analysis Methodology for Songs,Units 2 & 3 ML20198C3471998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Songs,Units 2 & 3 ML20195H2471998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Songs,Units 2 & 3 ML20154B7211998-10-0101 October 1998 Safety Evaluation Approving Licensee Request to Implement Alternatives Contained in Code Case N-546 for Current Interval at Songs,Units 2 & 3 Until Code Case Approved by Ref in Reg Guide 1.147 ML20154M7921998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for Songs,Units 2 & 3 ML20155F6081998-09-17017 September 1998 Non-proprietary Version of San Onofre 2 & 3 Replacement LP Rotors ML20151Z9851998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for Songs,Units 2 & 3 ML20151Q1211998-08-14014 August 1998 Rev 0 to Control of Hazard Barriers 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 ML20198G4491998-07-31031 July 1998 Rev 1 to WCAP-15015, Specific Application of Laser Welded Sleeves for SCE San Onofre Units 2 & 3 Sgs ML20237B8571998-07-31031 July 1998 Monthly Operating Repts for July 1998 for Songs,Units 2 & 3 ML20236N3871998-07-0909 July 1998 Part 21 Rept Re Deficiency Identified in Event 32725, Corrected by Mgp Instruments Inc.Licensee Verified,Affected Equipment Has Been Reworked & Tested at Sce.Design Mod Completed ML20236R1031998-06-30030 June 1998 Monthly Operating Repts for June 1998 for Songs,Units 2 & 3 ML20249A9431998-05-31031 May 1998 Monthly Operating Repts for May 1998 for Songs,Units 2 & 3 ML20248B8981998-05-26026 May 1998 Updated SG Run Time Analysis Cycle 9 ML20248B9221998-04-30030 April 1998 Rev 0 to AES 98033327-1-1, Updated Probabilistic Operational Assessment for SONGS Unit 2,Second Mid Cycle Operating Period,Cycle 9 ML20247L5181998-04-30030 April 1998 Monthly Operating Repts for Apr 1998 for Songs,Units 2 & 3 05000361/LER-1998-003, LOCA Evaluation of Safety Significance of Failure of Emergency Sump Valve Linestarter (LER 1998-003)1998-04-0606 April 1998 LOCA Evaluation of Safety Significance of Failure of Emergency Sump Valve Linestarter (LER 1998-003) ML20217Q6161998-04-0505 April 1998 Failure Analysis Rept 98-005,Failure Analysis of 2HV9305 Motor Starter ML20217A0141998-03-31031 March 1998 Monthly Operating Repts for Mar 1998 for Songs,Units 2 & 3 ML20217D4701998-03-0202 March 1998 Rev 1 to 90459, Failure Modes & Effects Analysis DG Cross- Tie,DCP7048.00SE ML20216J3551998-02-28028 February 1998 Monthly Operating Repts for Feb 1998 for Songs,Units 2 & 3 ML20203E7301998-02-17017 February 1998 SER Accepting 980105 Request to Use Mechanical Nozzle Seal Assembly as Alternate Repair Method,Per 10CFR50.55a(a)(3)(1) for Plant,Units 2 & 3 ML20203K9141998-02-0303 February 1998 Rev 0 to ESFAS Radiation Monitor Single Failure Analysis. W/96 Foldout Drawings ML20202F9731998-01-31031 January 1998 Monthly Operating Repts for Jan 1998 for Songs,Units 2 & 3 1999-09-30
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION C_0MBUSTION ENGINEERING OWNERS GROUP PROGRAM FOR EVALUATION OF PRESSURIZER SURGE LINE THERMAL STRATIFICATION NRC BULLETIN 88-11 INTRODUCTION By reports CEN-387-P, Revisions 0 and 1, " Pressurizer Surge Line Flow Stratification Evaluation," the Combustion Engineering Owners' Group (CE0G) demonstrated the integrity of the pressurizer surge line (PSL) in view of the occurrence of thermal stratification during 40-year service life as described in NRC Bulletin 88-11. The reports responded generically to the NRC concern for the following 15 Combustion Engineering (CE) plants:
50-528/50-529/50-530 Palo Verde, Units 1, 2, and 3 50-368 Arkansas Nuclear One, Unit 2 50-317/50-318 Calvert Cliffs, Units 1 and 2 50-255 Palisades 50-335/50-389 St. Lucie, Units 1 and 2 50-382 Waterford, Unit 3-50-309 Maine Yankee 50-336 Millstone, Unit 2 50-285 Fort Calhoun 50-361/50-362 San Onofre, Units 2 and 3 EVALUATION NRC Bulletin 88-11 required all licensees for pressurized water reactor (PWR)
Operating Plants to take the following actions to demonstrate that the integrity of PSLs is maintained for the 40-year design life of these piping systems.
1.a Perform a visual inspection walkdown (ASME Section XI, VT-3) at the first available cold shutdown which exceeds 7 days.
1.b Perform a plant-specific or generic-bounding analysis to demonstrate that the surge line meets applicable design codes and other Final Safety Analysis Report (FSAR) and regulatory commitments for the design life of the plant. The analysis is requested within 4 months for plants in operation over 10 years and within 1 year for plants in operation less than 10 years. If the analysis does not demonstrate compliance with these requirements, submit a justification for continued operation (JCO) and implement Actions 1.c and 1.d below.
9308190314 930802 PDR ADOCK 05000361 0 PDR
4 l.c Obtain data on thermal stratification, thermal striping, and line deflections either by plant-specific monitoring or through collective efforts among plants with a similar surge line design. If through collective efforts, demonstrate similarity in geometry and operation.
1.d Perform detailed stress and fatigue analyses of the surge line to ensure compliance with applicable code requirements incorporating any observations from 1.a. The analysis should be based on the applicable plant-specific or referenced data and should be completed within 2 years. If the detailed analysis is unable to show compliance, submit a JC0 and description of corrective actions for effecting long-term resolution. -
Although not required by the Bulletin, licensees were encouraged to work collectively to address the technical concerns associated with this issue, as well as to share the PSL data and operational experience. The CE0G implemented a series of programs to address the issue of surge line i stratification in CE plants.
The visual inspections of the surge lines, Action 1.a, have been addressed by each of the 15 CE plants. The walkdown results are included in CE0G report CEN-387-P. The inspections did not reveal indications of discernable distress or structural damage in any of the 15 CE plants. ,
The CE0G implemented a series of programs to satisfy the requirements of 1.b through 1.d. It was established that all CE plants have similar PSL t arrangements and loading conditions, hence, bounding analyses were used to generically evaluate the adequacy of the PSL design in all CE operating plants l with consideration of the effect of thermal stratification and thermal striping during its 40-year service life. These results were reported in the CE0G publication CEN-387-P, Revisions 0 and 1. Comparing the PSL thermal stratification data collected from three plants, the CE0G found that all large surge line top-to-bottom temperature differentials are caused by either an insurge or outsurge of the pressurizer. These fluid surges can result from a number of plant operations including spray initiation, energizing heaters, or the mismatch of charging / letdown flow. The data were tabulated and summarized to identify the numbers of transients measured at different ranges of delta-T.
These results were used as the basis for developing new design-basis transients.
Since the data on thermal stratification was based on outside wall temperature, two different assumptions of the inside fluid conditions were modeled to evaluate the outside wall temperatures. The first was a stratified i flow model defined by hot fluid (pressurizer temperature) in the upper portion of the pipe and cold fluid (hot leg temperature) in the lower half with a sharp interface in between. The second model was a uniform temperature :
gradient model in which the pipe cross section was divided into a finite '
number of water layers to approximate a continuous top-to-bottom temperature i fatigue gradient. Using the CE-Marc code, a number of heat transfer y, ;
calculations were performed on these two models. It was determined that the second assumed fluid condition yielded results somewhat consistent with the
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- measured in-plant data. However, the first model (stratified flow) provides for more conservatism in the stress and fatigue analyses, and was chosen to be used for analytic purposes. This application is acceptable. The original design basis transients used in the design and analysis of the NSSS including the PSL did not include any stratified flow loading conditions. CE developed a revised set of design-basis transients based on the thermal stratification test data collected as a part of this program. The revised transient data assumed 500 heatup-cooldown cycles, the same as the original assumption, but, i in addition, accounted for the number of stratification cycles that occur during each heatup-cooldown. Additional conservative assumptions included:
the entire horizontal section of the surge line was assumed to be uniformly ,
stratified, the maximum pressurizer-to-hot leg delta-T was assumed to be 340*F, and the total number of transients is greater than the expected number based on test data.
To satisfy the Bulletin concern regarding thermal striping, CE developed a one-dimensional finite element model to evaluate thermal striping at the inside of the pipe wall. Experimental data had shown that the amplitude of fluid temperature fluctuation near the pipe wall is smaller than the maximum temperature difference, and that the oscillation frequency varies and can '
cover a wiue range. CE considered four load cases with a fluid temperature range of 8% and 41% of the maximum temperature differential and a period of I second and 4 seconds. The local stresses due to each temperature gradient as a function of time were determined following the formulas in ASME Code Section :
III. To determine the striping contribution to fatigue, each striping transient stress range was combined with the corresponding numbers of cycles of the stratified flow stress ranges resulting in an alternating stress range for which an allowable number of cycles was determined. CE also performed fracture mechanics analysis, which concluded that existing cracks will not propagate appreciably into the surge line wall.
To satisfy Bulletin Action 1.d, and to verify that the revised design-basis transients were in compliance with ASME Code stress and fatigue requirements, CE performed a stress evaluation of the PSLs. The results of the elastic analyses exceeded the limit of 3S in all of the surge lines. Therefore, CE proceeded to use elastic-plastic , analyses to demonstrate the adequacy of the PSLs. A review of the CE evaluation raised two issues. The first issue involved an acceptable value for the deformation limit. To accommodate the small deformation theory, which is the analytic basis, and minimize the distortion interference with the neighboring components, CE selected the Code-case-permitted 5% as the limiting value. The elastic-plastic analysis demonstrated the maximum-accumulated strain at approximately half this limiting value. The second issue involved whether the austenitic stainless steel will strain harden with cyclic loading, resulting in an increase in the yield surface. CE concluded that the intent of the expansion stress criterion was satisfied by demonstrating that at shakedown, the strain range of the material, based on isotropic hardening and an increase in the yield surface, will be elastic in nature.
As a confirmatory action, CE initiated two ASME Code inquiries to obtain Code Committee concurrence on the approach and on the use of the isotropic strain
- r y .
hardening model discussed above. The Code Committee responses indicated that (1) when shakedown is demonstrated in accordance with NB-3228.4(b), the expansion stress criterion of NB-3222.3 need not be satisfied, and (2) in performing a plastic shakedown analysis, NB-3228.4 does not prohibit the use of either kinematic hardening or isotropic hardening to represent the motion of the yield surface due to strain hardening. Therefore the requirements to satisfy NB-3200 are demonstrated by showing the accumulated usage factor is less than one.
CONCLUSION Brookhaven National Laboratory (BNL) has performed a review of the CE0G ,
Reports CEN-387-P, Revisions 0 and 1, " Pressurizer Surge Line Flow Stratification Evaluation." BNL's evaluation is documented in a Technical Evaluation Report (TER) A-3869. The NRC has reviewed the TER and concurs with BNL that the methodology used to analyze the effects of thermal stratification and striping in the PSL is acceptable. Accordingly, we conclude that the results of the CE0G analysis may be used as the basis for CE0G licensees to update their plant-specific Code stress reports to demonstrate compliance with ,
applicable Code requirements as requested in Bulletin 88-11. '
However, due to the fact that elastic-plastic analysis was necessary in performing the PSL stress evaluation, the staff concurs with BNL's recommendation for performing enhanced inservice inspections to provide additional confidence in the structural integrity of the surge lines. The staff recommends that licensees perform volumetric examination of critical elbow components as part of future ASME Section XI inservice examinations.
Examinations of elbow bodies, as well as elbow welds, should be performed to ensure that the most highly-stressed areas have not sustained damage.
r Principal Contributor: H. Shaw Date: August 2, 1993 .
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