ML20045G317

Forwards 1993 Annual 10CFR50.46 Rept,Providing Updated Info Re Peak Clad Temp of Limiting Small Break & Large Break Loss of Coolant Accident Analysis Evaluations for Facilities

ML20045G317
Person / Time
Site:	Byron, Braidwood, Zion  File:ZionSolutions icon.png
Issue date:	07/06/1993
From:	Bauer J COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
NUDOCS 9307130177
Download: ML20045G317 (17)

Text

.

e Cornmonwealth Edison A,

One Rrst Nabonal Plaza. Ch<cago, llhnois v

AifdissR6pfy th Posf0fEBos767~

chicago, nknois 60690 0767 July 6,1993 Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attn: Document Control Desk

Subject:

1993 Annual 10CFR50.46 Report Zion Station Units 1 and 2 (NRC Docket Nos. 50-295/304)

Byron Station Units I and 2 (NRC Docket Nos. 50-454/455)

Braidwood Station Units I and 2 (NRC Docket Nos. 50-456/457)

References:

1.

July 25,1992 letter from M. A. Jackson (CECO) to Dr. T. E. Murley (NRC) 2.

April 20,1992 letter from S. F. Stimac (CECO) to Dr. T. E. Murley (NRC) l l

3.

December 22,1992 letter from M. A. Jackson (CECO) to Dr. T. E. Murley (NRC)

Dear Dr. Murley:

Pursuant to 10CFR50.46(a)(3)(ii), the attached annual report is being submitted for Units 1 and 2 of Zion, Byron, and Braidwood Nuclear Power Stations.

Reference i previously transmitted the 1992 Annual 10CFR50.46 Report for Byron and Braidwood. Reference 2 transmitted the revised Reload Transition Safety Analysis Report for Zion which included new Loss of Coolant Accident Analyses. Reference 3 transmitted a 30 day 10CFR50.46 report regarding the Small Break Loss of Coolant Accident Analysis for Byron and Braidwood.

Ml 12nos)~

)

9307130177 930706 i

PDR ADOCK 05000295 I R

PDR gg

(

Dr. T. E. Murley 2

July 6,1993 provides updated information regarding the Peak Clad Temperature (PCT) of the limiting Small Break and Large Break Loss of Coolant Accident analysis evaluations for Units 1 and 2 of Zion, Byron, and Braidwood. Attachment 2 contains a detailed description for each change or error reported.

10CFR50.46 acceptance criteria has been met with the existing PCT penalties, therefore, no near term reanalysis is planned for these units.

Please address any further comments or questions regarding this matter to this office.

Respectfully,

,/ csy>k k.

cu.ar

(' Joseph A. Bauer Nuclear Licensing Administrator i

JAB /gp l

Attachments cc:

J. B. Hickman, Byron Project Manager - NRR R. R. Assa, Braidwood Project Manager - NRR i

C. Y. Shiraki, Zion Project Manager - NRR

11. Peterson, Senior Resident inspector - Byron S. G. Dupont, Senior Resident Inspector - Braidwood J. D. Smith, Senior Resident inspector - Zion B. Clayton, Branch Chief - Region Ill

.--.-.---r

Attachment !

Comn. wealth Edison Company j

1993 Annual 10CFR50.46 Report PLANT NAME:

Braidwood Statinn UniLI.

ECCS EVALUATION MODEL:

Small Break LOCA REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE: 4 ANALYSIS OF RECORD Evaluation Model: NOTRUMP Calculation: Westinghouse SEC-SAll 3173-CO, July,1989 Fuel: VANTAGE 517 x 17 FQ = 2.50 FNAlI = 1.65 SGTP = 15%

Reference PCT PCT =

1453.1 F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS Fuel Rod Initial Condition inconsistency (Note 1)

APCT =

+37.0 F 1111S1 Surveillance (Note 2)

APCT =

+20.0 F SI Spilling Line Assumption Error (Note 3)

APCT =

+166.5 F Economic Generation Control (' Note 4)

APCT =

+5.0 F Missing Grid Piece (Note 5)

APCT =

+ 17.0 F B. CURRENT LOCA MODEL ASSESSMENTS None NET PCT PCT =

1698.6 F i

I l

t l

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

.~. -._

Commomvealth Edison Company 4

1993 Annual 10CFR50.46 Report PLANT NAME:

ILraidwood_ Station Unit _1 ECCS EVALUATION MODEL:

.I arge B eak LOCA t

REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE:

4-ANALYSIS OF RECORD Evaluation Model: basil Calculation: Westinghouse SEC-SAll 3157-CO, July,1989 Fuel: VANTAGE 517 x 17 FQ = 2.50 FNAll = 1.65 SGTP = 15%

Reference PCT PCT =

1883.1 F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS Fuel Rod initial Condition inconsistency (Note 1)

APCT =

+ 10.0 F SG Tube Seismic /LOCA Assumption (Note 6)

APCT =

+7.2 F Containment Mini Purge Assumption (Note 7)

APCT =

+1.0 F VANTAGE 5 Transition Penalty (Note 8)

APCT =

+50.0 F LB-LOCA Power Distribution (Note 9)

APCT = +100.0 F Missing Grid Piece (Note 5)

APCT =

+17.0*F B. CURRENT LOCA MODEL ASSESSMENTS WREFLOOD Structural Metal IIcat Model (Note 10)

APCT =

-25.0 F Economic Generation Control (Note 4)

APCT =

+4.0 F NET PCT PCT =

2047.3 F I

1 l

e

---

..-*.,u.-.~

..w,.

, -- - = -. -,

m m

m

.-.._--,,n..,

v

Commonwealth Edison Company 1993 Annual 10CFR50.46 Report PLANT NAME:

ILrai_d31gl Station Unitl ECCS EVALUATION htODEL:

Small Brgpk LOC 4 i

REPORT REVISION DATE:

06/01/03_

CURRENT OPERATING CYCLE: 4 ANALYSIS OF RECORD Evaluation Model: NOTRUMP 3

Calculation: Westinghouse SEC-SAll-3173-CO, July,1989 Fuel: VANTAGE 517 x 17 FQ = 2.50 FNA)i = 1.65 SGTP = 15%

Reference PCT PCT =

1453.1 F' MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS Fuel Rod initial Condition inconsistency (Note 1)

APCT =

+37.0 F f11ISI Surveillanec (Note 2)

APCT =

+20.0 F SI Spilling Line Assumption Error (Note 3)

APCT = + 166.5 F Economic Generation Control (Note 4)

APCT =

+5.0 F H. CURRENT LOCA MODEL ASSESSMENTS None NET PCT PCT =

168).6 F 4

I l

i, e

~-,,,

m

,-...-w

._ _ _=_. _..

' Attachment 1 Commonwealth Edison Company 1993 Annual 10CFR50.46 Report PLANT NAME:

BraidwoodJtation Unit 2 ECCS EVALUATION MODEL:

LArgq Break LOCA REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE: 4 ANALYSIS OF RECORD Evaluation Model: basil Calculation: Westinghouse SEC-S AII-3157-CO, July,1989 Fuel; VANTAGE 517 x 17 FQ = 2.50 FNall = 1.65 SGTP = 15%

Reference PCT PCT =

1883.1 F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS Fuel Rod Initial Condition Inconsistency (Note I)

APCT =

+10.0 F SG Tube Scismic/LOCA Assumption (Note 6)

APCT =

+20.0 F Containment Mini-Purge Assumption (Note 7)

APCT =

+1.0 F 1

LB LOCA Power Distribution (Note 9)

APCT =

+100.0 F B. CURRENT LOCA MODEL ASSESSMENTS WREFLOOD Structural Metal lleat Model (Note 10)

APCT =

-25.0 F Economic Generation Control (Note 4)

APCT =

+4.0 F NET PCT PCT =

1993.1 F l

l

,, _.. _ _, ~.

L Attachment I Commonwealth Edison Company 1993 Annual 10CFR50.46 Report PLANT NAME:

thron Station Unit 1 ECCS EVALUATION MODEL:

Emall Break LOCA REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE: 6 ANALYSIS OF RECORD Evaluation Model: NOTRUMP Calculation: Westinghouse SEC-SAll-3173-CO, July,1989 Fuel: VANTAGE 517 x 17 FQ = 2.50 FNAlI = 1.65 SGTP = 15%

Reference PCT PCT =

1453.1 F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS Fuel Rod Initial Condition inconsistency (Note 1)

APCT =

+37.0 F f illSI Surveillance (Note 2)

APCT =

+20.0 F SI Spilling Line Assumption Error (Note 3)

APCT = + 166.5'F Economic Generation Control (Note 4)

APCT =

+5.0 F B. CURRENT LOCA MODEL ASSESSMENTS None NET PCT PCT =

1681.6*F

'I i

1 s.'

Commonwealth Edison Company 1993 Annual 10CFR50.46 Report.

PLANT NAME:

Ihron Station Unill ECCS EVALUATION MODEL:

1.argq. Break LOCA REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE: 6 ANALYSIS OF RECORD Evaluation Model: B ASil.

Calculation: Westinghouse SEC-SAll 3157 CO, July,1989 4

Fuel: VANTAGE 517 x 17 FQ = 2.50 FNAll = 1.65 SGTP = 15%

Reference PCT PCT =

1883.1 F MARGIN Al. LOCATION A. PRIOR LOCA MODEL ASSESSMENTS Fuel Rod initial Condition inconsistency (Note 1)

APCT =>

410.0'F SG Tube Seismic /LOCA Assumption (Note 6)

APCT =

+7.2' F Containment Mini-Purge Assumption (Note 7)

APCT =

+1,0 F LB-LOCA Power Distribution (Note 9)

APCT = + 100.0 F i

IL CURRENT LOCA MODEL ASSESSMENTS WREFLOOD Structural Metal lleat Model (Note 10)

APCT =

-25.0 F 4

Removed Upper Internal Assembly Alignment Pins (Note 1I)

APCT =

+5.0 F Economic Generation Control (Note 4)

APCT =

4 4.0'F l

NET PCT PCT =

1985.3*F 1

_-.. ~

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

Attachment I Commonwealth Edison Company

' 1993 Annual 10CFR50.46 Report PLANT NAME:

Dymnjiatignynit_2 ECCS EVALUATION MODEL:

Sniall Bicall,01A REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE: 4 ANALYSIS OF RECORD Evaluation Model: NOTRUMP Calculation: Westinghouse SEC SAll 3173-CO, July,1989 Fuel: VANTAGE 517 x 17 FQ = 2.50 FNAll = 1.65 SGTP = 15%

Reference PCT PCT =

1453. l*F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS Fuel llod Imtial Condition inconsistency (Note 1)

APCT =

+3 7.0'F 111151 Surveillance (Note 2)

APCT=

+20.0 F SI Spilling Line Assumption Error (Note 3)

APCT = + 166.5 F Economic Generation Control (Note 4)

APCT =

+5.0 F B. CURRENT LOCA MODEL ASSESSMENTS None NET PCT PCT =

1681.6 F

.g i

i

(

d E

4 e

=w

.-e-

--e

,.-.w,,

,,,~4-.--...-,m.--

e

~

Attachment !

Commonwealth Edison Company 1993 Annual 10CFR50.46 Report PLANT NAME:

Dyron Statiqn_11 nil 2 ECCS EVALUATION MODEL:

Large Ikeak LOCA REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE: 4 ANALYSIS OF RECORD Evaluation Model: basil Calculation: Westinghouse SEC-SAll-3157 CO, July,1989 Fuel: VANTAGE 517 x 17 FQ = 2.50 FNAll = 1.65 SGTP = 15"'o Reference PCT PCT =

1883.1 F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS Fuel Rod initial Condition inconsistency (Note 1)

APCT =

+ 10,0 F SG Tube Seismic /LOCA Assumption (Note 6)

APCT =

+20.0 F Containment Mini-Purge Assumption (Note 7)

APCT =

+ 1.0* F Economic Generation Control (Note 4)

APCT =

+4.0"F VANTAGE 5 Transition Penalty (Note 8)

APCT =

+50.0 F LB LOCA Power Distribution (Note 9)

APCT = + 100.0* F i

IL CURRENT LOCA MODEL ASSESSMENTS WREFl.OOD Structural Metal lleat Model (Note 10)

APCT =

-25.0 F NET PCT PCT =

2043.1 F l

H i

~ _

J i

Commonwealth Edison Company i

1993 Annual 10CFR50.46 Report i

PLANT NAME:

Zion _ Station Unit 1 ECCS EVALUATION MODEL:

Small llreak LOCA REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE: H ANALYSIS OF RECORD Evaluation Model: NOTRUMP Calculation: Westinghouse SEC-SAll-3659-C3, April,1992 Fuel: VANTAGE 515 x 15 without IFMs FQ = 2.50 i

FNAll = 1.70 SGTP = 15%

Reference PCT PCT =

1963,0 F MARGIN ALLOCATION A. PRIOR I.OCA MODEL ASSESSMENTS None 11 CURRENT LOCA MODEL ASSESSMENTS Fuel Assembly Reconstitution (Note 12)

APCT=

+l.0 F NET PCT PCT =

1964.0 F 1

)

l l

Commonwealth Edison Company 1993 Annual 10CFR50 46 Report PLANT NAME:

ZiojtStation UniL1 ECCS EVALUATION MODEL:

Large Brea}; LSCA REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE: 12 ANALYSIS OF RECORD Evaluation Model: basil Calculation: Westinghouse SEC-SAll 3609-C3, April,1992 Fuel: VANTAGE 515 x 15 without IFMs FQ = 2 A0 FNAll = 1.65 SGTP = 15%

Reference PCT PCT =

2065.0*F MARGIN ALLOCATION 4

A. PRIOR LOCA MODEL ASSESSMENTS None IL CURRENT LOCA MODill ASSESSMENTS WREFLOOD Structural Metal lleat Model (Note 10)

APCT =

-25.0 F Contairunent Mini Purge Assumption (Note 7)

APCT =

+1.0 F Fuel Assembly Reconstitution (Note 12)

APCT =

+2.0 F NET PCT PCT =

2043.0 F l'

i i

i n

,.,---,,,--,--~e--.

Commonwealth Edison Company 1993 Annual 10CFR50.46 Report PLANT NAME:

ZLqn1tation UniL2 ECCS EVALUATION MODEL:

SmalL[LryaklOCA REPORT REVISION DATE:

06/01/93 CURRENT OPERATING CYCLE: 13 ANALYSIS OF RECORD Evaluation Model: NOTRUMP Calculation: Westinghouse SEC-SAll-3659-C3, April,1992 Fuel: VANTAGE 515 x 15 without IFMs FQ = 2.50 FNAll = 1.70 SGTP e 15%

4 Reference PCT PCT =

1963.0 F 1

MARGIN ALLOCATION A PRIOR LOCA MODEL ASSESSMENTS None IL CURRENT LOCA MODEL ASSESSMENTS None NET PCT PCT =

1963.0*F i

l i

l l

t I

l.

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

4 4

^

Conunonwealth Edison Company 1993 Annual 10CFR50.46 Report PLANT NA.ME:

7agnjitalipaltnit_2 ECCS EVALUATION MODEL:

!strgeJhgd LOCA REPORT REVISION DATE:

pf6]O1L92 CURRENT OPERATING CYCLE: 13 ANALYSIS OF RECORD Evaluation Model: HASit Calculation: Westinghouse SEC-SAll-3609 C3, April,.1992 Fuel: VANTAGE 515 x 15 without IFMs FQ = 2.40 FNAll = 1.65 SGTP = 15%

Reference PCT PCT =

2065.0 F MARGIN ALLOCATION A. PRIOR I.OCA MODEl, ASSESSMENTS None i

B CURRENT LOCA MODEL ASSESSMENTS WREFLOOD Structural Metal lleat Model (Note 10)

APCT =

25.0*F Cycle 13 As Huilt Fuel Margins (Note 13)

APCT =

+3.0 F Centainment Mini Purge Assumption (Note 7)

APCT =

+1.0 F NET PCT PCT =

2044.0"F l

l l

-m

.- - -. - - _ - _ ~

I Commonwealth Edison Company 1993 Annual 10CFR50.46 Report Table Notations

1. he.LihunitiaLCelition incon2inene s

This penalty results from an inconsistency between the LOCA fuel rod models and the corresponding rod nxxlels in the design codes. This inconsistency was corrected in 1991. ECCS analysis performed after 1991 used the corrected fuel rod models; therefore, this penalty is not apphcable to Zion Units I and 2.

2. UllSI Surveillance A temporary penalty of no more than 20*F was assessed by Westinghouse in support of a potential change to the charging pump surveillance acceptance limit. This proposed change is still under -

review and has not yet been submitted for NRC approval. The small break LOCA penalty would result from a slight reduction in delivered SI under spilling line conditions between 1000 and 1400 psia RCS pressure.

3. SLSpiHinricingAssumptionI!r(of This penalty is the result of the incorrect modeling of the centrifugal charging pump injection flow to the broken RCS loop. The analysis of record assumes that the ECCS branch line to the broken loop spills to RCS backpressure. but due to the relative sizes of the limiting break (3") and the injection line (1.5"), the assumed injection flow must be reduced.

4. liconotujtGergmtion Contrgj This penalty is the result of a safety evaluation to evaluate the efTects of operation on Economie l

Generation Control (EGC). The penalty is a result of an increase in the uncertainty of the pressurizer pressure initial condition while operating in EGC mode. This penalty does not apply to Zion due to restrictions placed on EGC operation at high power,

5. MissingGrid Piqce This penalty is the result of potential flow blockage at a fuel assembly lower nozzle due to j

unrecovered debris in the reactor. The debris is a small (approximately 0,5 inches square) piece of a torn grid strap form assembly C22S. This assembly was damaged during fuel movement following Braidwood Unit I Cycle 2. This penalty applies to Braidwood Unit 1 only.

6 KLTube_Svismig!LOm\\ssumntion This penalty results from the poten*ial decrease in flow area through th cam generator tubes.

The combined forces of a large Dreak LOCA. the primary depressurization, and a SSE may cause in a small fraction of the steam generator tubes to collapse. The reduced flow area increases the resistance to \\enting of steam generated in the core during the reflood phase of the LOCA. This potential flow area reduction was explicitly modeled in the Zion large break evaluations by assuming that an additional 5% of the tubes are plugged.

s Commonwealth Edison Company j

1993 Annual 10CFR50 46 Report Table Notations

7. Omtainnwnt3]inMPyrgv_Asyumption j

This penalty resulted from an evaluation of the containment mini-purge valve as described in the Uyron/Braidwood UFSAR Section 6.2.1.5 A similar evaluation has been performed for Zion.

The penalty results from the lower containment backpressure during the blowdown phase of the.

l LOCA assuming the mini-purge valves are open and do not close until the isolation signal is generated plus appropriate delays.

R VANTACdli5 Imnsition Evnalty This 50'F penalty is applied to the results of Large Dreak LOCA due to differences in the hydraulic resistance of reload cores containing both OFA and VANTAGE 5 fuel Zion Units I and 2 utilize VANTAGE 5 fuel without the intermediate Flow Mixing (IFMs) grids. The Zion 15x15 VANTAGE 5 fuel is hydraulically equivalent to the 15x15 OFA, so no penalty is applied.

Hraidwood Units I and 2 and Hyron Unit 2 are mixed cores and include the penalty, Byron Unit I Cycle 6 is a pure VANTAGE 5 core, so no penalty is applied

9. LH-LOCMmvvtDistrilmting Appendix K to 10CFR50 requires that the power distribution which results in the most severe calculated consequences be used in the ECCS Evaluation Model calculations. The current basis for all Westinghouse large break LOCA evaluations is the chopped cosine power distribution.

Calculations were performed with basil which examined peak power locations and power distributions which were not considered in the original analysis, Under some circumstances, these evaluations lead to PCTs greater than those calculated with the cosine distribution. Byron and Braidwood Units 1 and 2 include a conservative temporary penalty of 100*F to bound the effects of other power shapes CECO has chosen to operate under the generic JCO until the NRC approses WCAP 12909-P, Westmghouse ECCS Evaluation Model: Revised Large Break LOCA Power Distribution Methodology." Zion Units I and 2 apply a surveillance factor penalty to the measured value of Fu to ensure that the chopped cosine power shape remains bounding. This process is also justified under the generic JCO.

10 WRE F LOOll.St ructu ral3f etalj l. cat 31 odd The 25'F henefit is the result of a correction in the calculation of heat transfer from the structural metal in the sessel during the rellood stage. The material properties assumed in the analysis of l

record correspond to those of Stainless Steel. While this is correct for internal structures, it is mappropriate for the vessel wall which consists of carbon steel with a stainless steel clad.

II lkmm e(Upps rj n te rnalA tsemblyAlignmenLb n s This penalty is the result of a safety evaluation to address the removal of five bent alignnKnt pins i

from the reactor Upper Internals at assembly locations R-9 (both pins) P-9 (both pins), and N 9, These alignment pins were damaged during reactor reassembly preceding Byron Unit 1 Cycle 6.

l l

b T l

Conunonwealth Edison Company L

1993 Annual 10CFR50.46 Report Table Notations l

12.

Eucl AssembhJlc.qorntitutisn Tins penalty is assessed on a cycle specific basis to account for power distribution anomalies associated with the replacement ofleaking fuel pins with stainless steel filler rods. Following is a list of the reconstituted fuel in service and the cumulative penalty associated with the reconstitution. The penalty is assigned to the entire core, not the individual assembly.

1 Installed Reconstituted Fuel Assemblies Assembly ID Cumulative Penalty Plant Unit Cycle llraidwood i

4 None 0"F Braidwood 2

4 None 0F Hyron 1

6 G74F 0F Hyron 2

4 None 0F Zion 1

13 M17A 1*F M24A (small break)

E29C 2F E32C (large break)

Zion 2

13 None 0F 13.

CycitL3.As_thijldtiel Margins.

The as-built fuel mechanical properties used in the fuel rod model in the Analysis of Record was based on Zion I Cycle 13 fuel. The penalty has been applied to account for small non-conservative differences between the fuel properties of Zion 2 Cycle 13 and the properties assumed in the Analpis of Record 1

m,.,. - - -

_-....--n-__.-.-,--m-~-.

-