SVP-99-058, Submits Plant Specific ECCS Evaluation Changes,Per Annual Reporting Requirements of 10CFR50.46.Attachments Include Current Assessment Data Re PCT Info Limiting LOCA Evaluations

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Submits Plant Specific ECCS Evaluation Changes,Per Annual Reporting Requirements of 10CFR50.46.Attachments Include Current Assessment Data Re PCT Info Limiting LOCA Evaluations
ML20205R649
Person / Time
Site: Quad Cities  Constellation icon.png
Issue date: 04/14/1999
From: Dimmette J
COMMONWEALTH EDISON CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
SVP-99-058, SVP-99-58, NUDOCS 9904230255
Download: ML20205R649 (24)
v • d • e


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( untos a ,11. 612 i 2 9 io i rl .Sm,s i 22 a SVP 99-058 April 14,1999 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D C 20555 Quad Cities Nuclear Power Station, Units 1 and 2 Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265 l l

Subject:

Plant Specific Emergency Core Cooling System (ECCS) Evaluation I Changes, Annual 10 CFR 50.46 Report i

References:

(1) Letter from J. P. Dimmette, Jr. (Comed), SVP-98-366, to l USNRC dated December 18,1998,

  • Quad Cities Nuclear Power Station Unit 1, Facility Operating License No. DPR-29, NRC Docket No. 50-254, Plant Specific Emergency Core Cooling l System (ECCS) Evaluation Changes - 10CFR50.46 Report" l

(2) Letter from D. A. Sager (Comed), SVP-98-146, to USNRC dated i April 17,1998, " Quad Cities Nuclear Power Station Units 1 and 2 l Plant Specific Emergency Core Cooling System (ECCS) l Evaluation Changes - 10CFR50.46 Report DPR-29 and DPR-30, NRC Docket Nos. 50-254 and 50-265" The purpose of this letter is to fulfill the annual reporting requirement of 10 CFR 50.46,

" Acceptance criteria for emergency core cooling systems for light water nuclear power  ;

reactors," for Quad Cities Nuclear Power Station. '

Reference (1) transmitted the most recent Peak Clad Temperature (PCT) change for Quad Cities Nuclear Power Station to the Nuclear Regulatory Commission. Reference (2) was the last annual PCT report. The attachments provide updated information regarding the PCTs for the Loss of Coolant Accident (LOCA) analyses of record.

Attachments 1 and 2 provide PCT information for the limiting LOCA evaluations for Unit 1. Attachments 3 and 4 provide PCT information for the limiting LOCA evaluations f - Unit 2. The attachments include current assessment data. The }

assessment notes, Attachment 5, provide a detailed description for each change or error reported.

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9904230255 990414 PDR ADOCK 05000254 P PDR ,

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April 14,1999 '

U.S. Nuclear Regulatory Commission .

Page 2 j Unit 1 General Electric (GE) Fuel:

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This 10 CFR 50.46 report includes the PCT and all of the assessments for the co-resident GE fuel used for Quad Cities Unit 1, Cycle 16. The GE fuel PCT is {

calculated by GE and there have been no changes to the Unit 1 PCT assessments 1 since the last 10 CFR 50.46 transmittalin Reference (1). The PCT for GE fuel remains at 2025 degrees F as described in Attachment 1.

Unit 1 Siemens Fuel:

Siemens Power Corporation (Slemens) LOCA analysis for ATRIUM -9B fuel PCT is also being reported because it is the fresh fuel with the co-resident GE fuel for Quad Cities Unit 1 Cycle 16. The accumulation of the absolute magnitude of input errors and model errors in the Siemens ECCS evaluation models has resulted in a calculated PCT difference of +20 degrees F for Unit 1. As described in Attachment 2 the PCT increased from 1967 degrees F to 1987 degrees F for ATRIUM -9B fuel.

This is based on an explicit PCT calculation using NRC approved Siemens BWR  !

EXEM methodology.

The Unit 1 initial 10 CFR 50.46 report for the introduction of ATRIUM -9B fuel was given in Reference (1). A detailed description of the Siemens LOCA analysis and error evaluations are given in Attachment 5.

Unit 2 GE Fuel-Similar to Unit 1, GE fuel is the co-resident fuel used for Quad Cities Unit 2, Cycle 15.

The GE fuel PCT is calculated by GE Since the last annual 10 CFR 50.46 transmittal, Reference (2), there have been five changes to the Unit 2 PCT  :

assessments that resulted in no change to the PCT. The PCT for GE fuel remains at i 1850 F as described in Attachment 3.

Unit 2 Siemens Fuel:

Similar to Unit 1, the LOCA analysis for ATRIUM *-9B fuel PCT is also being reported because it is the fresh fuel with the co-resident GE fuel for Quad Cities Unit 2, Cycle 1

15. The accumulation of the absolute magnitude of input errors and model errors in the Siemens ECCS evaluation models has resulted in a calculated PCT difference of

+25 F for Unit 2. The PCT increased from 1884 F to 1909 F for ATRIUM -98 fuel.

This is based on an explicit PCT calculation using NRC approved Siemens BWR EXEM methodology.

The initial 10 CFR 50.46 report for the introduction of ATRIUM -9B fuel for Unit 2 was given in Reference (2). A detailed description of the Siemens LOCA analysis and error evaluation is given in Attachment 5.

i April 14,1999 l U.S. Nuclear Regulatory Commission Page 3 Should you have any questions conceming this letter, please contact Mr. Wally Beck, Acting Regulatory Assurance Manager, at (309) 654-2241, extension 3100.

Res ectfully,

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Joel P. Dimmette, Jr.

Site Vice President Quad Cities Nuclear Power Station Attachments: 1: Quad Cities Unit 1,10 CFR 50.46 Report (GE Fuel) i 2: Quad Cities Unit 1,10 CFR 50.46 Report (Siemens Fuel) 3: Quad Cities Unit 2,10 CFR 50.46 Report (GE Fuel) 4: Quad Cities Unit 2,10 CFR 50.46 Report (Siemens Fuel) 5: Quad Cities Units 1 and 2,10 CFR 50.46 PCT Assessment Notes l cc. Regional Administrator- NRC Region ll1 l NRC Senior Resident inspector- Quad Cities Nuclear Power Station l

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Attachment 1 Quad Cities Unit 1,10 CFR 50.46 Report (GE Fuel)

SVP-99-058 (Page 1 of 2)

PLANT NAME: ,Ouad Cities Unit 1 REPORT P.EVISION DATE: 4/17/99 CURRENT OPERATING CYCLE: 1Q ANALYSIS OF RECORD ECCS Evaluation Model: SAFER /GESTR LOCA, NEDE-24011-P A-8-US, May 1986 Calculation: General Ele ctric document NEDC-31345P, Revision 2, dated July, 1989 Fuel: P8x6R/BP8x8R, which bounds GE8, GE9 and GE10 Limiting Single Failure: Battery Failure Limiting Break Size and Location: 1.C Doub!c Ended Guillotine Recirculation Suction Line Break l

MARGIN ALLOCATION (on the following page) l

r-l Attachment 1 Quad Cities Unit 1,10 CFR 50.4G Report (GE Fuel)

SVP-99-058 (Page 2 of 2) l l

Reference PCT PCT = 1382*F MARGIN ALLOCATION i

A. PRIOR LOCA MODEL ASSESSMENTS

  • l LPCI injection delay to 75 seconds (Note 1) A PCT = +288"F Extended Operating Domain and Equipment OOS (Note 2) A PCT = +10"F  :

Safety Evaluation Report for Core Spray Header Flaw (Note 3) A PCT = +110*F  !

Replacement Access hole cover modification (Note 4) A PCT = +10 F l CS injection valve stroke time increased to 50 seconds (Note 5) A PCT = +0 F '

Bottom Head Drain Flowpath (Note 6) A PCT = +10*F i Remove NRC SER requirement for Core Spray Header Flaw I (Note 7) A PCT = -110 F l CS Tee Box repair including CS piping leakage (Note 8) A PCT = +40*F Jet Pump Riser repair penalty (Note 9) A PCT = +20*F Shroud repair including access hole cover (Note 10) A PCT = +15'F Remove penalty for Replacement Access hole cover (Note 11) A PCT = -10*F LPCI and CS injection pressure permissive (Note 14) A PCT = +10 F LPCI, HPCI and CS reduction due to minimum flow (Note 15) A PCT = +75*F LPCI system reduced shut off head capability (Note 16) A PCT = +0*F LPCI Loop Select Delay (Note 24) A PCT = +0 F HPCI Fluid Temperatures Range (Note 25) A PCT = +0 F 4 LPCI and CS Pumps initiating Signals (Note 26) A PCT = +0*F I ADS Valves Opening and Closing Delay Time (Note 27) A PCT = +0 F DG Total Output Closure Time Delay (Note 28) A PCT = +0*F MSIV Closure Initiation Time (Note 29) A PCT = +0 F Jet Pump Riser Flaw penalty (Note 30) A PCT = +175*F Prior Assessments PCT PCT = 2025"F

  • Reported to USNRC on December 18,1998 B. CURRENT LOCA MODEL ASSESSMENTS l None Total PCT Change from Current Asser,sments [ APCT = 0F Cumulative PCT Change from Current Assessments [lAPCy= 0F j NET PCT PCT = 2025'F l

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Attachment 2 Quad Cities Unit 1,10 CFR 50.46 Report (Siemens)

SVP-99-058 (Page 1 of 2)

PLANT NAME: Quad Cities Unit 1 REPORT REVISION DATE: 4/17/99 CURRENT OPERATING CYCLE: 1.s ANALYSIS OF RECORD Evaluation Model: Advanced Nuclear Fuels Corporation Methodology for Boiling Water Reactors EXEM BWR Evaluation Model, ANF 91-048(P)(A), dated January,1993, (Note 13).

Calculations:

1. " Quad Cities LOCA-ECCS Analysis MAPLHGR Limits for ATRIUM-98 Fuel,"

EMF 96-185(P), Revision 4, Siemens Power Corporation, dated August 1998.

2. 'LOCA Break Spectrum Analysis for Quad Cities Units 1 and 2," I EMF 96-184(P), Siemens Power Corporation, dated January 1997.

Fuel: ATRIUM *-9B  :

Limiting Single Failure: LPCI Injection Valve l Limiting Break Size and Location: 1.0 (DEG) Double-Ended Guillotine in a Recirculation Suction Pipe MARGIN ALLOCATION (on the following page)

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Attachment 2 I Quad Cities Unit 1,10 CFR 50.46 Report (Siemens Fuel)

SVP-99 058 (Page 2 of 2)

! Reference PCT (see Note 13) PCT = 1880*F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS

  • LPCI and CS injection pressure permissive (Note 14) A PCT = 0*F LPCI, HPCI and CS reduction due to minimum flow (Note 15) A PCT = 44*F LPCI system reduced shut off head capability (Note 16) A PCT = +0*F HPCI Operating Pressure Range and initiation delay (Note 17) A PCT = +0 F Siemens Fuel Pellet Grain Size Error (Note 18) A PCT = +0*F Siemens HUXY Strain Error (Note 19) A PCT = +0 F j Siemens RDX2LSE Gadolinia Conductivity Error (Note 20) A PCT = +0*F Siemens Capture Ratio for High Exposures Error (Note 21) A PCT = +0*F Siemens Accommodation Densities Error (Note 22) A PCT = +5*F Siemens RDX2LSE Gadolinia Density Model Error (Note 23) A PCT = +0*F LPCI Loop Select Delay (Note 24) A PCT = +0*F HPCI Fluid Temperatures Range (Note 25) A PCT = +0 F LPCI and CS Pumps initiating Signals (Note 26) A PCT = +0*F ADS Valves Opening and Closing Delay Time (Note 27) A PCT = +0*F DG Total Output Closure Time Delay (Note 28) A PCT = +0 F MSIV Closure Initiation Time (Note 29) A PCT = +0 F Jet Pump Riser Flaw penalty (Note 30) A PCT = +78'F Prior Assessments PCT PCT = 1967 F ,
  • Reported to USNRC on December 18,1998 l B. CURRENT LOCA MODEL ASSESSMENTS Siemens RDX2LSE Corrosion Model Error (Note 31) A PCT = +0*F ,

Siemens RDX2LSE Gadolinia Fission Gas Release Error (Note 32) A PCT = +0 F Siemens RELAX Decay Heat Renormalization Error (Note 33) A PCT = +10 F l Siemens RELAX Fuel Average Temperature Error (Note 34) A PCT = +10 F l Total PCT Change from Reference PCT [ APCT = +20 F Cumulative PCT Change from Current Assessments [l APC7] = +20 F NET PCT PCT = 1987*F 1

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. . . 1 Attachment 3 Quad Cities Unit 2,10 CFR 50.46 Report (GE Fuel) i SVP-99-058 (Page 1 of 2)

PLANT NAME: Quad Cities Unit 2 REPORT REVISION DATE: 4/17/99 CURRENT OPERATING CYCLE: 15 ANALYSIS OF RECORD ECCS Evaluation Model: SAFER /GESTR-LOCA, NEDE 24011-P-A-8-US, May 1 1986 Calculation: General Electric document NEDC-31345P, Revision 2, dated July, 1989 Fuel: P8x8R/BP8x8R, which bounds GE8, GE9 and GE10 Limiting Single Failure: Battery Failure Limiting Break Size and Location: 1.0 Double Ended Guillotine Recirculation Suction Line Break l

MARGIN ALLOCATION (on the following page)

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l Attachment 3 Quad Cities Unit 2,10 CFR 50.46 Report (GE Fuel)

SVP-99-058 (Page 2 of 2) 1 Reference PCT PCT = 1382*F ,

1 MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS

  • LPCI injection delay to 75 seconds (Note 1) A PCT = +288*F Extended Operating Domain and Equipment OOS (Note 2) A PCT = +10 F Safety Evaluation Report for Core Spray Header Flaw (Note 3) A PCT = +110 F Replacement Access hole cover modification (Note 4) A PCT = +10 F CS injection valve stroke time increased to 50 seconds (Note 5) A PCT = +0*F Bottom Head Drain Flowpath (Note 6) A PCT = +10 F Remove NRC SER requirement for Core Spray Header Flaw (Note 7) A PCT = -110*F CS Tee Box repair including CS piping leakage (Note 8) A PCT = +40*F Jet Pump Riser repair penalty (Note 9) A PCT = +20 F Shroud repair including access hole cover (Note 10) A PCT = +15*F Remove penalty for Replacement Access hole cover (Note 11) A PCT = -10 F LPCI and CS injection pressure permissive (Note 14) A PCT = +10 F LPCI, HPCI and CS reduction due to minimum flow (Note 15) A PCT = +75*F LPCI system reduced shut off head capability (Note 16) A PCT = +0*F LPCI Loop Select Delay (Note 24) A PCT = +0 F Prior Assessments PCT PCT = 1850 F l
  • Reported to USNRC on April 17,1998 B. CURRENT LOCA MODEL ASSESSMENTS HPCI Fluid Temperatures Range (Note 25) A PCT = +0*F LPCI and CS Pumps initiating Signals (Note 26) A PCT = +0 F ADS Valves Opening and Closing Delay Time (Note 27) A PCT = +0 F DG Total Output Closure Time Delay (Note 28) A PCT = +0*F MSIV Closure Initiation Time (Note 29) A PCT = +0*F Total PCT Change from Current Assessments [ APCT = 0F Cumulative PCT Change from Current Assessments [lAPCy= 0*F NET PCT PCT = 1850*F

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Attachment 4 Quad Cities Unit 2,10 CFR 50.46 Report (Slernens Fuel)

SVP-99-058 (Page 1 of 2)

PLANT NAME: Quad Cities Unit 2 REPORT REVISION DATE: 4/17/99 CURRENT OPERATING CYCLE: 15 ANALYSIS OF RECORD Evaluation Model: Advanced Nuclear Fuels Corporation Methodology for Boiling Water Reactors EXEM BWR Evaluation Model, ANF-91-048(P)(A), dated January,1993, (Note 13).

Calculations:

1. " Quad Cities LOCA-ECCS Analysis MAPLHGR Limits for ATRIUM-9B Fuel,"

EMF- 96-185(P), Revision 4, Siemens Power Corporation, dated August 1998.

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2. "LOCA Break Spectrum Analysis for Quad Cities Units 1 and 2," EMF 96- '

184(P), Siemens Power Corporation, dated January 1997, Fuel: ATRIUM *-98 I Limiting Single Failure: LPCI Injection Valve Limiting Break Size and Location: 1.0 (DEG) Double Ended Guillotine in a Recirculation Suction Pipe l;

l MARGIN ALLOCATION (on the following page) i 1

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r Attachment 4 Quad Cities Unit 2,10 CFR 50.46 Report (Siemens Fuel)

SVP-99-058 (Page 2 of 2)

Reference PCT (see Note 13) PCT = 1880*F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS

  • LPCI and CS injection pressure permissive (Note 14) A PCT = 0*F LPCI, HPCI and CS reduction due to minimum flow (Note 15) A PCT = +4*F LPCI system reduced shut off head capability (Note 16) A PCT = +0*F HPCI Operating Pressure Range and initiation delay (Note 17) A PCT = +0*F Siemens Fuel Pellet Grain Size Error (Note 18) A PCT = +0*F Siemens HUXY Strain Error (Note 19) A PCT = +0*F Siemens RDX2LSE Gadolinia Conductivity Error (Note 20) A PCT = +0*F Prior Assessments PCT PCT = 1884*F
  • Reported to USNRC on April 17,1998 B. CURRENT LOCA MODEL ASSESSMENTS Siemens Capture Ratio for High Exposures Error (Note 21) A PCT = +0*F Siemens Accommodation Densities Error (Note 22) A PCT = +5"F Siemens RDX2LSE Gadolinia Density Model Error (Note 23) A PCT = +0 F LPCI Loop Select Delay (Note 24) A PCT = +0*F HPCI Fluid Temperatures Range (Note 25) A PCT = +0 F LPCI and CS Pump 3 Initiating Signals (Note 26) A PCT = +0*F ADS Valves Opening and Closing Delay Time (Note 27) A PCT = +0*F DG Total Output Closure Time Delay (Note 28) A PCT = +0*F MSIV Closure Initiation Time (Note 20) A PCT = +0*F Siemens RDX2LSE Corrosion Model Error (Note 31) A PCT = +0*F Siemens RDX2LSE Gadolinia Fission Gas Release Error (Note 32) A PCT = +0*F Siemens RELAX Decay Heat Renormalization Error (Note 33) A PCT = +10 F Siemens RELAX Fuel Average Temperature Error (Note 34) A PCT = +10 F Total PCT Change from Reference PCT [ APCT = +25'F Cumulative PCT Change from Current Assessments {lAICy= +25*F NET PCT PCT = 1909'F

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1 Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99-058 (Page 1 of 13)

1. Delav in LPCI from 48 seconds to 75 seconds after LOCA initiation l

On April 11,1990, an Auto-Transfer Logic Operability Surveillance was completed during a Unit 2 outage. Part of this surveillance includes timing the transfer of Motor Control Center loads from Bus 29 to Bus 28 during L simulated Loss of Offsite Power (LOOP) with a failure of the Unit 2 Diesel Generator (DG). The transfer was timed at 38.99 seconds. The acceptance criteria for the time delay was 20 i 5 seconds. At Comed's request, GE evaluated the consequences of a LOCA for this as-found relay setpoint drift. This evaluation assessed the impact of a time delay in Low Pressure Coolant inspection (LPCI) injection due to power transfer during a LOCA and LOOP with a battery failure. GE determined that delaying the LPCIinjection time to 75 seconds after the initiation of a LOCA resulted in a +288 *F PCT increase. GE's practice has been to delay LPCI injection until the Recirculation pump discharge valve is completely closed. This valve is normally powered from Bus 29. Therefore, LPCI injection time is the Auto-Transfer Logic time plus the Recirculation pump discharge valve stroke time. The as found relay setpoint drift would have resulted in a LPCI injection time of 63 seconds (39 seconds for the as-found transfer time and 24 seconds for the slowest Unit 2 Recirculation discharge valve). Comed immediately restored the Auto-Transfer Logic to its design value of 20 seconds.

Later in 1993, an error was discovered in the analysis of record for the LPCI delay time. The analysis of record did not correctly apply the dependence of the Recirculation discharge valve motive power on the transfer time of Bus 29, which was described in a thirty day 10 CFR 50.46 report, dated March 26,1993. The total LPCI delay is expected to be 70 seconds, i.e. 25 seconds for the swing bus transfer and a maximum of 45 seconds for the Recirculation discharge valve closure. Therefore, the j GE fuel rchins a delayed LPCI PCT penalty. Both Unit LOCA analyses currently maintain a conservative LPCI injection time input value at 75 seconds.

2. Extended Operatino Domain /Eouloment Out Of Service (EOD/EOOS)

The report, " Extended Operating Domain and Equipment Out Of Service for Quad- l Cities Nuclear Power Station Units 1 and 2," GE Document NEDC-31449, Revision 1, April,1992, analyzed Quad Cities for an Extended Operating Domain (EOD) allowing increased core flow above nominal values. The following Equipment Out-Of-Service j (EOOS) and EOD operating modes were included as part of the analysis: Feedwater i Heaters Out-Of-Service, Single Recirculation Loop Operation (SLO), Relief Valve Out-Of-Service, increased Core Flow (ICF), and Final Feedwater Temperature Reduction.

The Extended Load Line Limit region and the ICF region of the power / flow map were  ;

supported for all fuel types used. Table 1 summarizes the combined modes of operation analyzed in the EOD and EOOS document for Quad Cities. Note that with the exception of the SLO condition, the EOOS analyses are valid for the ICF region. ,

The conclusions of the EOD and EOOS report for Quad Cities assessed the impact ,

on LOCA PCT as less than +10 *F. l

Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99458 (Page 2 of 13)

Table 1 Equipment Out of Service (OOS) Analysis and Extended Operating Domain for Quad Cities Units 1 and 2 EQUIPMENT OUT OF SERVICE APPLICABLE OPERATING DOMAIN 4 Relief Valve-OOS EOD Including ICF Region Feed Water Heater-OOS EOD including ICF Region Feed Water Heater -OOS and EOD including ICF Region Relief Valve-OOS Singit Recirculation Loop Operation EOD Excluding ICF Region Single Recirculation Loop Operation EOD Excluding ICF Region and Relief Valve -OOS

3. Reactor Vesselleakaae assessed for the start un of Unit 1 Cycle 14 Emergent leakage paths associated with core shroud flaws, core spray piping flaws (repaired prior to the start up of Unit 1, Cycle 15) and jet pump riser flaws (repaired prior to the start up of Unit 1, Cycle 14) were evaluated and assigned PCT increases.

For the Unit 1 restart, emergent leakage paths described above resulted in an increase in PCT of 110 F as accepted in the NRC SER letter from Chandu P. Patel dated August 4,1994. This increase resulted in a limiting PCT of 1790 'F for Unit 1 only. As a result of subsequent repairs to the Unit 1 Shroud and Core Spray line, the increase in PCT of 110 *F from the NRC SER was removed and replaced with separate PCT assessments associated with each repair. Note that the NRC SER 110 F PCT increase was imposed on Unit 1, Cycle 14 only.

4. Reolacement access hole cover The PCT increase was applied to Quad Cities with the modification of the access covers in the core shroud support plate. These removable covers allow access from the downcomer region to the lower plenum region. This modification changed the design of the access cover from a welded design to a bolted design. The small amount of leakage associated with the bolted joint was analyzed and resulted in less  ;

than a 10 *F PCT increase. Note that leakage from these access covers was included in each of the subsequent LOCA evaluations. Note 12 contains a summary of leakage, which has an impact on LOCA/ECCS analysis.

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Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99458

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(Page 3 of 13)

5. CS Inlection valve maximum stroke time increased from 15 to 50 seconda l

Modification of the CS injection valve stroke time was necessary as a part of the NRC Generic Letter 89-10 " Safety Related Motor Operated Valve Testing and Survaillance," compliance. The supporting LOCA evaluation addressed the impact of increasing the CS injection valve stroke time from a maximum of 15 seconds to a maximum of 50 seconds. This analysis credits the partial CS flow while valves are stroking open which compensates for the longer injection valve stroke times. GE completed the analysis using their licensed SAFER /GESTR methods and determined >

there was no change to the LOCA PCT,

6. Bottom Head Drain Flowcath GE reported under 10 CFR 50.46 on December 15,1995, that the impact of the Reactor Pressure Vessel (RPV) Bottom Head Drain (BHD) providing an additional flow path for coolant loss under LOCA conditions was an increase less than 10 *F on the PCT. Continuous Reactor Water Cleanup (RWCU) system operation takes suction from the BHD and from the recirculation suction piping which are connected at a common point. A design basis LOCA, where the break is on the recirculation suction piping, would allow water in the lower plenum of the reactor vessel to be lost through the RWCU piping where it connects to the Recirculation suction piping. Note 12 l contains a summary of leakage that has an impact on LOCA/ECCS analysis. I
7. Remove increase in PCT of 110 *F (from NRC SER reauirement, see note M As a result of the repairs to Unit 1 Shroud and CS line, the increase in PCT of 110 *F ;

required by the NRC SER in note 3 was removed and replaced with PCT i assessments associated with each repair. Note that the NRC SER 110 F PCT ,

increase was imposed on Unit 1, Cycle 14 only. i

8. CS Tee Box repair includina CS oicina leakaae The purpose of the assessment was to analyze the impact of installing the CS Tee l Box repair clamp. This modification was necessary as a result of cracks found in the Unit 1 Tee Box and a subsequent commitment to the NRC to repair it. This assessment is also being applied to Unit 2 to account for calculated leakage in the Unit 2 CS piping. This PCT assessment was done for 4,100 GPM of CS delivered to the top of the core. The previous LOCA analysis was performed with 4500 GPM of  ;

CS delivered to the top of the core. The maximum CS leakage was calculated to be J less than 400 GPM with the Unit 1 CS Tee Box repair which included the flaw and the design leakage from the thermal sleeve / safe end interface. The leakage calculated l

for Unit 1 conservatively bounds the leakage calculated for Unit 2. This 400 GPM of leakage used in the LOCA analysis, when subtracted from the Technical Specifications required 4500 GPM, conservatively assumes leakage in excess of the maximum calculated l

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Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99-058 (Page 4 of 13) leakage for Unit 1. This 400 GPM reduction in CS flow results in the 40 *F PCT penalty. An additional 450 gpm per CS pump reduction, for Unit 1 only, was conservatively analyzed to bound issues identified in note 30. This 450 gpm has an additional PCT penalty as described in note 30. This excess leakage can be used for assessment of consequences for any additional CS line flaws that may occur in the future. Note 12 contains a summary of leakage that has an impact on LOCNECCS analysis.

9. Jet Pumo Riser repair Potential leakage paths associated with Unit 1 Jet Pump Riser 5/6 cracks on recirculation loop "A," repaired prior to the start up of Unit 1, Cycle 14 were evaluated !

and assigned PCT increases. GE evaluated the PCT increase for two leakage scenarios, which were evaluated and submitted to the NRC on July 14,1994. In that letter, the nominal leakage scenario, including the Core Spray flaw along with the repaired Jet Pump Riser, resulted in an increase in PCT of 20 *F. This increase in PCT of 20 F is associated with the nominalleakage from the Jet Pump Riser repair.

Although Unit 2 was not found to have any jet pump riser cracks with leakage, this leakage penalty is also being conservatively applied to Unit 2 for consistency between the Units. Note 12 contains a summary of leakage that has an impact on LOCA/ECCS analysis.

10. Shroud reDair includino access hole cover j i

Repairs to the Quad Cities core shroud were completed prior to the start up of Unit 1, Cycle 15 and prior to the start up of Unit 2, Cycle 14. These repairs included installation of hardware, which required machining of holes in the shroud and shroud  !

support plate. Each of these holes has some clearance that will allow some leakage l to occur at the hole's location. The leakage of the cracks found in the shroud were  !

included in the repair PCT assessment. This repair on each Unit resulted in a PCT increase of 15 F when compared to the LOCA analysis without any shroud leakage.

Included in the assessment was the replacement access hole cover leakage. This increase in PCT of 15 F is associated with the leakage from the shroud repair and replacement access hole cover. Note 12 contains a summary of leakage that has an impact on LOCA/ECCS analysis. l

11. Remove replacement access hole cover uenalty As a result of the shroud repair assessment, which included access hole cover leakage, the increase in PCT of 10 F from the modification specific assessment was l removed and replaced with PCT assessment associated with shroud repair.
12. ECCS Leakaoe Summary Leakage values that ieduce the effectiveness of the ECCS have been calculated for both Quad Cities Unit 1 and Unit 2. The following table and associated notes address the source of the leakage, the amount of leakage, and how the calculated leakage is conservatively analyzed.

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Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99458 (Page 5 of 13)

Quad Cities ECCS Leakage Summary Leakage Source Current Current Currently Currently Unit 1 Unit 2 Analyzed Analyzed Calculated Calculated Urlt1 Unit 2 Leakage Leakage Leakage Leakage (GPM) (GPM) (GPM) (GPM) 20 Jet Pump Slip Joints 225 225 225 225 10 Jet Pump Bolted Joints 582 582 582 582 (LPCI Only) 2 Access Hole Covers less 1 146 146 146 146 bolt Core Shroud Weld Cracks 150 150 150 150 Core Shroud Weld Repair 350 350 350 350 Holes Bottom Head Drain Line 480 480 480 480 Jet Pump Riser 5/6 Crack, 180 0 1080+ 180*

loop "A" only (LPCI )*

Jet Pump Riser 7/8 Crack, loop 373 0 + 0 "A" only (LPCI )#

Jet Pump Riser 19/20 Elbow 25 0 + 0 Crack, loop "B" only (LPCI )#

Core Spray Piping Flaw"* near 7.5 31 850" 400" rated system flow perloop RPV assembly penetration 103 103 Thermal Sleeve / Safe End Interface Vent Holes in Core Spray Line 8 8 Tee-box Core Spray Line Tee-box 144 0 Flaws w/ Repair

+ The 1080 gpm of LPCI leakage for Unit 1 (180 gpm for note 9 plus 900 gpm for note

30) analyzed for 2 LPCI pumps injecting bounds the maximum determined leakage from either loop "A" or loop "B." Quad Cities utilizes LPCI loop select logic.
  1. See Assessment Note 30
  • See Assessment Note 9
    • The analyzed CS pump leakage (400 gpm for Units 1 & 2 as described in note 8, plus 450 gpm for Unit 1 only as described in note 30) listed in the table covers the CS line postulated crack leakage, RPV assembly leakage, upper Tee-box vent hole leakage, and the CS line Tee-box flaws with repair. Since all of these !eakages occur in the CS line between its entry into the vessel and the penetration of the core shroud, the distribution of these leakages is insignificant. Conservatively, none of the CS leakage flow is credited to enter the vessel.

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Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessrnent Notes SVP-99-058 (Page 6 of 13)

"* Initial crack sizes were reduced based on high resolution ultrasonic inspections.

The end-of-cycle crack lengths (including the projected crack growth) were used to calculate the leakages used for this analysis. Comed's projected crack growth period used in the LOCA analysis for a given flaw is consistent with the schedule for re-inspection of that flaw. This ensures that appropriate leakage is used in the LOCA PCT evaluation. Comed will use end of life leakage flows for flaws that cannot be verified by re-inspection.

13. Introduction of Siemens ATRIUM-9B fuel to Ouad Cities Station Beginning with Unit 2, Cycle 15 and Unit 1, Cycle 16, Siemens ATRIUM-9B fuel will be co-resident in the core with General Electric fuel. Comed tracks the LOCA/ECCS evaluation models of these fuels separately through the respective vendors approved LOCA/ECCS evaluation methodologies. Comed has ensured that there is consbtency between the analyzed licensing basis configuration and assumptions for the two respective LOCA/ECCS analyses of record. In certain cases, differences exist based on methodology. These differences were initiated to assure conservative 10CFR50.46 results within that vendor's methodology. As a result of using Siemens methodology, Siemens calculated a different limiting single failure than the previous GE analysis. The change in the limiting single failure is a result of applying the Siemens methodology and it is not due to the use of the Siemens ATRIUM
  • 9B fuel.

Siemens has demonstrated the hydraulic compatibility of the ATRIUM -9B and GE 8

fuel and concluded that the mixed core effects have a negligible impact on the PCT calculation. Therefore, the GE PCT calculation for the GE fuel remains applicable, and the Siemens PCT calculation is appropriate for the ATRIUM *-98 fuel.

The currently used methodology by Siemens Power Corporation (EXEM BWR [ANF-91-048(P)(A))) requires the use of a conservative, constant ECCS injection temperature. Siemens has determined that an elevated value yields the most conservative PCT results. The value used for the Quad Cities Siemens LOCA analysis was 170 *F and 120*F was used for the GE SAFER /GESTR-LOCA analysis.

The value Siemens used conservatively bounds the maximum suppression pool temperatures for the initial period of the LOCA during which the PCT is reached and then mitigated. This temperature was derived from the suppression pool analysis as shown in the Updated Final Safety Analysis Repor1 (UFSAR), section 6.2, Figure 6.2-18.

Siemens Power Corporation methodology also utilizes a reflood criteria liquid entrainment flow rate which allows the switch from a hot channel steam cooling Appendix K heat transfer coefficient to the Appendix K spray cooling heat transfer coefficient. The Siemens FLEX computer code is used to determine the core and system response during the reflood and refill phases of a LOCA. A sustained non-zero value for relative entreinment has been the criteria that FLEX uses to determine the time of core reflood. In this analysis, Siemens has applied a conservative supplemental reflood criteria of absolute entrained liquid flow rate at the plane of interest to determine the time of core reflood. Siemens determined that a revised absolute entrained liquid flow rate is appropriate for the

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Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99-058 (Page 7 of 13)

The Siemens ATRIUM -9B fuel reflood criteria flow rate was empirically demonstrated to effectively quench a cladding temperature excursion with a full sized ATRIUM-98 bundle test apparatus. Siemens presented the revised supplemental criteria to the NRC on January 9,1997, and provided an information letter on January 21,1997, to document the supplemental criteria.

In February,1997, Siemens reported an error on the application of the HUXY code.

The HUXY code is used to perform heatup calculations for the entire LOCA transient and yields PCT and local oxidation at the axial plane of interest. HUXY uses the time dependent pressure difference across the fuel cladding to determine the amount of strain experienced by the cladding and the resulting potential for rod ballooning and rod failure. The internal rod pressure is calculated by HUXY, while the time dependent system pressure is obtained from the blowdown and refill /reflood calculations. The approach of using a constant system pressure of 14.7 psia was mistakenly thought to be conservative since the occurrence of fuel failures during an accident increases PCT and Metal Water Reaction rate. However, it was discovered that using a larger cladding pressure difference is not always conservative. Siemens performed the Quad Cities limiting LOCA/ECCS analyses properly applying the time dependent pressure calculated during blowdown and refill /reflood to the HUXY heat up caiculation. Siemens identified and removed the error from the Quad Cities limiting case and addressed the HUXY system pressure error PCT impact on the non-limiting break spectrum analysis. The error resulted in a maximum of +32*F above the calculated PCTs for certain small break size cases. Siemens re-analyzed certain non-limiting cases with the error removed to confirm that the break spectrum analysis had correctly identified the most limiting break size, location and single failure.

14. LPCI and CS iniection pressure permissive During a detailed review of the LOCA analysis input parameters, the use of 325 psig, in the middle of the TS range of 300 to 350 psig for the analyzed vessel pressure permissive setpoint for CS and LPCI, was identified as a non-conservative input value. This 325 psig setpoint was used in the GE analysis but 300 psig was appropriately used in the Siemens analysis. The more conservative choice for the pressure permissive would have been 300 psig in the GE analysis. A ;ower pressure permissive is most conservative in the allowed range due to maximizing the potential delay to delivery of LPCI or CS flow to mitigate the fuel temperature excursion. The impact of lowering the analyzed pressure permissive setpoint from 325 psig to 300 psig was assessed and assigned a PCT increase by GE. GE assessed the PCT increase for impact on CS and LPCI separately. The PCT increase was +10 *F for CS and 0 *F for LPCI. GE does not expect the limiting single f ailure, break size and location to change as a result of the combined impact of the issues assessed in notes 14,15 and 16.

Since the correct and conservative value of 300 psig was appropriately used in the Siemens analysis, there was no impact on the Siemens PCT. Therefore, the impact on the Siemens fuel was 0 F .

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Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99-058 (Page 8 of 13)

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15. LPCI. HPCI and CS reduction due to minimum flow bvoass During a detailed review of the Quad Cities LOCA analysis input parameters, the minimum flow bypass in the ECCS was identified as not completely accounted for in the routine TS surveillances. Minimum flow bypass valves were open for the suwei!!ance testing of LPCI and HPCI, but not for CS. Minimum flow bypass for LPCI, in the suNeillance tests, was only considered at the rated flow and not at snut off head conditions. Minimum flow bypass was completely accounted for in the HPCI surveillance testing, including the LOCA analysis required delivery of rated flow within 45 seconds of actuation. However, surveillance testing of the CS did not require the minimum flow bypass valves to be open for the typical rated flow test conditions.

Minimum flow bypass at shut off head conditions was not accounted for in any test procedure for CS. Censideration for reduction of ECCS due to minimum flow bypass over each system's operating pressure range is conservative due to maximizing the potential reduction to delivery of LPCI or CS flow to mitigate the fuel temperature excursion. The impact of accounting for the LPCI and CS minimum flow bypass was assessed and assigned a PCT increase by both GE and Siemens.

GE assessed the PCT increase forimpact on CS and LPCI separately. The PCT increase was +25 *F for CS and +50 F for LPCI. GE does not expect the limiting single failure, break size and location to change as a result of the combined impact of the issues assessed in notes 14,15 and 16. Therefore, The GE analysis total PCT penalty is +75 *F for the combined effect of minimum flow on CS and LPCI.

Siemens analyzed the PCT increase for impact on CS and LPCI. The PCT increase was +4 F for CS and +0 F for LPCI. Since the limiting PCT case for Siemens is the LPCI injection valve single failure, reductions in LPCI do not have impact on the limiting case, but it does slightly increase the PCT of non-limiting cases. Siemens concluded that the limiting single f ailure, break size and location does not change as a result of the combined impact of the issues assessed in notes 15 and 16.

16. LPCI system reduced shut off head capability During a detailed review of the LOCA analysis input parameters, the maximum head at which LPCI can inject water into the reactor was identified as not consistent with the original or actual system perfom1ance. The maximum head at which LPCI can inject waterinto the reactor is termed the LPCI shut off head. Both GE and Siemens LOCA analysis used 325 psig as the shut off head for CS and LPCI. This value was identified as a non-conservative input value for LPCI but appropriate for CS. 260 psig is an appropriately conservative value for LPCI shut off head. Consideration for reduction of LPCI, due to reduced shut off head, is conservative due to maximizing the potential reduction to delivery of flow to mitigate the fuel temperature excursion. The impact of accounting for the reduced LPCI shut off head was assessed by both GE and Siemens.

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Attachment 5 )

Quad Cities Unit 1 and Unn 2,10 CFR 50.46 PCT Assessment Notes )

SVP-99 058 (Page 9 of 13) i GE assessed the PCT for impact on LPCI. The PCT increase was +0 F. GE does not expect the limiting single failure, break size and location to change as a result of the i combined impact of the issues assessed in notes 14,15 and 16. j I

, Siemens analyzed the PCT increase for impact on LPCI. The PCT increase was +0 F l . Since the limiting PCT case for Siemens is the LPCI injection valve single failure, reductions in LPCI do not have impact on the limiting case but it does slightly increase the PCT of non-limiting cases. Siemens concluded that the limiting single failure, break size and location does not change as a result of the combined impact of the issues assessed in notes 15 and 16.

17 HPCI Operatina Pressure Ranoe and Initiation delav l During a detailed review of the Siemens LOCA analysis input parameters, the operating pressure range at which High Pressure Coolant injection (HPCI) can inject water into the reactor was identified as inconsistent with the original design or actual system performance. The maximum reactor pressure at which HPCI can inject water q into the reactor is 1120 psig. An appropriate HPCI maximum operating pressure range was used in the GE analysis but 1015 psig was conservatively used in the Siemens analysis. This value was identified as an overly conservative input value for HPCI. The original design performance of HPCI, injecting up to 1120 psig, is an appropriately conservative value for HPCI and is routinely verified with TS surveillance tests.

During the review, the crediting of partial flow of HPCn, while the injection valve is stroking open in the Quad Cities Siemens LOCA analysis, was identified as inconsistent with the TS surveillance tests. While the HPCI system performance has met the Siemens analysis requirements, the analyzed values have been revised to credit rated HPCI flow only after 45 seconds have passed following initiation.

The impact of accounting for the revised HPCI operating pressure range and initiation delay was assessed by Siemens. The PCT increase was +0 F . Since the limiting PCT case for Siemens is the large break LPCI injection valve single f ailure, changes in HPCI do not have an impact on the limiting case. Large breaks depressurize so rapidly that HPCI does not have sufficient time to deliver a significant amount of water. Siemens concluded that the limiting single failure, break size and location does not change as a result of the combined impact of the issues assessed in notes 15,16 and 17.

18. Siemens uel Pellet Grain Size Error

' in October,1997, Siemens Power Corporation (SPC) informed Comed of an j inconsistency between fuel grain size production and the grain size assumed in the j mechanical analyses. The analysis of record used a pellet grain size greater than the most recent fuel production averaged values. SPC performed an evaluation for the impact on the LOCA analysis and concluded that the difference in fuel grain size will have no impact on the analysis of record. The fuel grain size can have a small affect I l

on the intemal rod pressure and stored energy at higher exposures. A smaller grain size would reduce the stored energy. However, since the limiting PCT occurs at very low exposures, there is no impact on the analysis of record for ATRIUM-9B fuel.

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Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99-058 (Page 10 0f 13)

19. Siemens HUXY Strain Error in December,1997, Siemens reported to Comed that the HUXY code had an internal pressure calculation error. The calculation used the instantaneous strain instead of the maximum strain. The HUXY code yields PCT and local oxidation at the axial plane of interest. Siemens corrected the error in the method used to calculate the internal rod pressure to use maximum strain versus instantaneous strain. The correction has been estimated to have no change on previously calculated peak l cladding temperatures for ATRIUM-9B fuel. Therefore, no PCT penalty or benefit was j assigned to ATRIUM-9B fuel.
20. Siemens RDX2LSE Gadolinia Conductivity Error 1

In January,1998, Siemens reported to Comed inat the gadolinia conductivity model l described in the methodology document (85 Gad Model) was not incorporated in the 4 RDX2LSE code. The RDX2LSE code is used to perform thermal and mechanical fuel  !

rod calculations, which are an input to the fuel heat up code that yields PCT and local i oxidation at the axial plane of interest. Siemens concluded that impact of using the l 79 Gad Model in BWR LOCA analyses was insignificant and is conservative. '

Therefore, no PCT penalty or benefit was assigned to ATRIUM-98 fuel.

21. Siemens Capture Ratio for Hioh Exoosures Error In September of 1998, Siemens reported to Comed that the Capture Ratio used in the high exposure analyses is incorrect because it was based on beginning of life (BOL) exposure. For the high exposure analyses, a capture ratio based on BOL would result in lower cladding temperature. The analyses performed for Quad Cities showed that the impact of using appropriate Capture Ratios for high exposure fuelis less than

+15 F increase in cladding temperature at exposures greater than 25 GWd/MTU.

The PCTs at these high exposures have more than 45 F margin to the limiting PCT.

The analysis of record, which is based on BOL, always had the correct Capture Ratio.

Therefore, no PCT penalty was assigned to the ATRIUM-9B fuel.

22. Siemens Accommodation Densities Error In September of 1998, Siemens reported to Comed that the asymptotic fuel density that occurs after full densification and full accommodation of the solid swelling by the as-fabricated fuel porosity, other wise known as the variable SWMDEN, was not properly input into the RDX2LSE code for the applicable fuel batch. This RDX2LSE code is used to perform thermal and mechanical fuel rod calculations, which are input to the fuel heat up code that yields PCT and local oxidation at the axial plane of interest. Siemens determined that the correct value for SWMDEN delayed the time for hard contact, but that hard contact did eventually occur. This resulted in a lower fuel pellet to inner cladding gap conductance calculated by RDX2LSE. This has the effect of increasing fuel stored energy during a LOCA event and increasing the PCT.

Siemens concluded that there was impact from using the improper accommodation densities in BWR LOCA analyses. A +5 F PCT penalty was assigned to ATRIUM-98 fuel for this correction.

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Attachment 5 i Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99-058 (Page 11 of 13)

23. Siemens RDX2LSE Gadolinia Density Model Error In October,1998, Siemens reported to Comed that the gadolinia density correlation, as used in the fuel weight calculation, was not properly incorporated in the RDX2LSE I

code. The RDX2LSE code is used to perform thermal and mechanical fuel rod calculations which are an input to the fuel heat up code that yields PCT and local oxidation at the axial plane of interest. Siemens concluded that the impact of using the l incorrect gadolinia weight calculation in BWR LOCA analyses was less significant than i the gadolinia conductivity error identified in note 20. Therefore, no PCT penalty or benefit was assigned to ATRIUM-9B fuel.

24. LPCI Looo Select Delav l During a detailed review of the LOCA analysis input parameters, the LPCI Loop Select delay was changed from 3 seconds to 5.25 seconds. This change was evaluated for both GE and Siemens fuel. It was determined that no PCT penalty or benefit for all fuel types was required because of this change.

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! 25. HPCI Fluid Temperatures Ranoe During a detailed review of the LOCA analysis input parameters, the HPCI Fluid l Temperatures Range was changed from 40-170 to 40-140 F. This change was evaluated for both GE and Siemens fuel. It was determined that no PCT penalty or benefit for all fuel types was required because of this change.

26. LPCI and CS Pumos initiatino Slanals During a detailed review of the Quad Cities LOCA analysis input parameters, the LPCI and CS pumps initiating signals and setpoints were identified as: High Drywell Pressure, Low-Low Water Level coincident with Low Reactor Pressure, or Low-Low Water Level for 8.5 continuous minutes. The Low Reactor Pressure value should be 300 psig. These initiating signals had been simplified as High Drywell Pressure or Low-Low Water Level for LPCI initiation in previous LOCA analysis. Since the high drywell pressure would be present at the time of the Low-Low waterlevel, there is no change to the timing for LPCI initiation. It was determined that no PCT penalty or benefit for all fuel types was required because of this change.
27. ADS Valves Openino and Closino Delav Time During a detailed review of the LOCA analysis input parameters, the inputs for the Automatic Depressurization System (ADS), which utilizes the Relief Valves, were changed. As part of the initiation and performance of the ADS, the valves opening and closing delay time was considered. Opening time delays, up to 1.85 seconds and closing delay times up to 10 seconds, were examined. It was determined that no PCT l penalty or benefit for all fuel types was required because of this change.

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Attachrnent 5 l Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes  !

SVP-99-058 (Page 12 of 13)

28. DG Total Outout Closure Time Defav During a detailed review of the LOCA analysis input parameters, the total DG output closure time changed from 13 seconds to 15 seconds. The DG start time delay to detect Loss Of Offsite Power was changed from 1 second to 2 seconds. The DG start i signal only requires a few milliseconds. The DG is started and breaker closed within l 10 seconds per the Technical Specifications. There is an inherent time delay in the reset of the undervoltage relays that requires a maximum of 3 seconds. No loads can i be sequenced on the ECCS bus until the undewoltage signalis reset. Therefore, a {

total of 15 seconds are conservatively required for the DG to be able to accept all  !

l automatic shutdown loads. It was determined that no PCT penalty or benefit for all fuel types was required because the existing analysis timelines are conservative.

29. MSIV Closure initiated on Low-Low level or Hioh Drywell pressure only During a detailed review of the LOCA analysis input parameters, inputs for the MSIV closure were identified as being initiated on Low-Low level or High Drywell pressure only. The Siemens LOCA analysis only assumed that MSIV closure initiates after 1.0 second. It was determined that no PCT penalty for ATRIUM-98 fuel was required because the existing analysis is conservative.
30. Jet Pumo Riser Flaws During Unit 1 refueling outage 15 in-vessel visual inspections, a potential leakage I

path associated with Jet Pump Riser 19/20 elbow cracks (i.e. in recirculation Loop "B")

was identified. This reload was associated with the start up of Unit 1, Cycle 16. The crack was evaluated and determined to be bounded by the previous LOCA analysis.

The crack was conservatively bounded since the 180 gpm of Jet Pump Riser 5/6 in Recirculation loop "A" leakage bounds the 25 gpm of Jet Pump Riser 19/20 elbow leakage in recirculation loop "B". Quad Cities is a LPCI Loop Select logic plant such that LPCI will be injected into the intact loop, not both loops.

Potential leakage paths, associated with Jet Pump Riser 7/8 cracks (i.e. in recirculation Loop "A") were evaluated under an operability assessment and were assigned PCT increases. A compensatory action has been administratively placed to monitor the Jet Pump Riser 7/8 to detect any growth in the small observed flaws. A maximum LOCA analysis leakage was determined based on a conservative crack size l above the threshold of detectability at rated power conditions. Detectable leakage, at rated conditions, will result in appropriate actions to trip Recirculation Loop "A". These cracks are similar to those found in Unit 1 Jet Pump Riser 5/6 in Recirculation Loop "A," with the start up of Cycle 14 as described in note 9. Under LOCA conditions, the l existing flaw size leakage was determined to be 15 GPM. The postulated crack size, if propagated above the threshold of detectability, has a leakage of 373 gpm. The impact on ECCS performance due to the Jet Pump 7/8 Riser flaws has been addressed by applying LOCA analysis results which conservatively bound the maximum leakage. This bounding case has 900 gpm for 2 LPCI pumps and 450 gpm per l

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Attachment 5 Quad Cities Unit 1 and Unit 2,10 CFR 50.46 PCT Assessment Notes SVP-99058 ,

- *. (Page 13 of 13) l l

l . CS pump reduction in ECCS flow rates as described in the Reference (1) LOCA

! analysis for GE and Siemens fuel types. Separate cases were analyzed for GE and Siemens fuel. The bounding GE case resulted in an increase in PCT of 175 F and the bounding Siemens case resulted in an increase in PCT of 78 F. Note 12.

contains a summary of the determined leakage and the consewatively analyzed L leakage which has impact on LOCA/ECCS analysis.

31. Siemens RDX2LSE Corrosion Model Error In December,1998, Siemens reported to Comed that there were two issues with the l corrosion model in the RDX2LSE code. First, the NRC approved corrosion model in ANF-88-133(P)(A) was not incorporated into RDX2LSE. Instead it had been implemented into RODEX2 used in the mechanical calculations. Secondly, there were errors in the programming of the MATPRO corrosion modelin RDX2LSE. The RDX2LSE code usage was described in note 20. Siemens concluded that the impact of both RDX2LSE errors in the BWR LOCA analyses was insignificant. Therefore, no PCT penalty or benefit was assigned to ATRIUM-9B fuel.
32. Siemens RDX2LSE Gadolinia Fission Gas Release Error in December,1998, Siemens reported to Comed that there was an error in the fission gas release calculation for Gadolinia fuel in the RDX2LSE code. The error resulted in an overprediction of the Gadolinia rod fission gas release by 10% at end of life conditions. The RDX2LSE code usage was described in note 20. Siemens concluded that the impact of this error in BWR LOCA analyses was insign2icant and consewative. Therefore, no PCT penalty or benefit was assigned to ATRIUM-9B fuel.
33. Siemens RELAX Decav Heat Renormalization Error j Siemens reported to Comed that the renormalization of the fission product decay heat multiplier incorrectly adjusted the multiplier to slightly less than 1.2 in the RELAP4 portion of the RELAX code. The error also affected the multiplier on the actinides.

The RELAX code is used to perform system calculations including the core decay heat power during the reflooding phase of the LOCA calculations. Siemens concluded in FebnJary,1999, that the impact of renormalization error in LOCA analyses was a small +10'F PCT increase. Therefore, the PCT penalty was assigned l to ATRIUM-9B fuel.  !

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34. SIE mens RELAX Fuel Averaoe Temoerature Error  ;

Siemens reported to Comed that the fuel average temperature in the RELAP4 portion of the RELAX code was incorrectly calculated using one-half of the volume of the first gap node in the calculation of the fuel volume. The RELAX code is used to pedorm system calculations including the core decay heat power during the reflooding phase  ;

of the LOCA calculations. Siemens concluded in February,1999 that the impact of the fuel average temperature error in LOCA analyses was a small +10 F PCT increase. Therefore, the PCT penalty was assigned to ATRIUM-9B fuel.

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