ML18010A726
| ML18010A726 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 08/26/1992 |
| From: | Mccarthy D CAROLINA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NLS-92-231, NUDOCS 9209010008 | |
| Download: ML18010A726 (6) | |
Text
ACCELERATED QiYSTRIBUTIONDEMO RATION SYSTEM REGULARLY INFORMATION DISTRIBUTION. YSTEM (RIDS)
ACCESSION NBR: 920'7010008 DOC. DATE: 92/08/26 NOTARIZED:
NO DOCKET 0 FACIL:50-000 Shearon Harv is Nucleav'ower Planti Unit 1> Carolina 05000400 AUTH. NAME AUTHOR AFFILIATION MCCARTHYiD. C.
Cav olina Power 8c Light Co.
REC IP. NAME RECIPIENT AFFILIATION Document Control Bv anch (Document Contv ol Desk)
SUBJECT:
Provides 30-day vept of estimated effect of change in application of small break LOCA ECCS evaluation model.
Calculated performance of ECCS continues to meet performance acceptance criteria in 10CFR50. 46.
DISTRIBUTION CODE:
10010 CDPZES RECEIVED'TR Q,ENCL Q SZZE:
TITLE:. OR Submit ta 1: General Dis tribut ion NOTES: Application fov'ev'mit v eneeal filed.
R S
05000400 RECIPIENT ID CODE/NAME PD2-1 LA LE> N INTERNAL: ACRS NRR/DOEA/OTSB11 NRR/DST/SICB8H7 NUDQCS-ABSTRACT QGC/HDS1 RES/DS IR/E1 8 COPIES LTTR ENCL RECIPIENT ID CODE/NAME PD2-1 PD NRR/DEl/ESGB NRR/DST/SELB 7E NRR/DST'/SRXB 8E REG FILE COPIES LTTR ENCL p
p S
EXTERNAL:
NRC PDR NOTE TO ALL 'RIDS RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK.
ROOhI P 1-37 (EXT. 504-2065) TO ELIMINATEYOUR NAh!E FROhI DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 22 ENCL ~8
SKK Carolina Power 8 Light Company AUG 36 1992 SERIAL:
NLS-92-231 10 CFR 50.46 United States Nuclear Regulatory Commission ATTENTION:
Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT DOCKET NO. 50-400/LICENSE NO. NPF-63 EMERGENCY CORE COOLING SYSTEM EVALUATION MODEL CHANGES Gentlemen:
The purpose of this lett:er is to provide a 30-day report pursuant to 10 CFR 50.46(a)(3)(ii) for the Shearon Harris Nuclear Power Plant (SHNPP) regarding the estimated effect of a change in the application of the Small Break LOCA Emergency Core Cooling System (ECCS) evaluation model.
As required by 10 CFR 50.46(a)(3)(ii),
CP&L herein provides notification of a significant change in the Peak Clad Temperature (PCT) predicted by the Small Break LOCA ECCS acceptable evaluation model.
The significant change is specific to the Small Break LOCA Analysis and has two parts:
As part of CP&L's review of the draft Westinghouse Reload Safety Evaluation for Cycle 5, the RCS pressure of 2280 psia used as an initial condition in the Large Break LOCA calculation was questioned.
The 2280 psia was based on the traditional 2250 +30 psia used originally in the FSAR accident analyses.
However, this value was not consistent with the current accident analyses allowance for RCS pressure variation.
The "Westinghouse Improved Thermal Design Procedure Instrument Uncertainty Methodology for CP&L Shearon Harris Nuclear Power Station,"
WCAP-12340, presents the current allowance as the combination of a +38 psi random uncertainty and a -12 psi bias.
This same WCAP also increases the +4'F allowance for variation in RCS average temperature to +5.3'F.
Evaluation of the corrected allowances for initial RCS pressure and temperature resulted in an increase in large PCT that was not significant (i.e., 6.3'F).
- However, the inconsistency had a more pronounced impact on the SBLOCA analysis.
Evaluation of corrected allowances resulted in a permanent SBLOCA PCT assessment of +17.2'F.
While the +17.2'F effect on Small Break LOCA is still below the 50'F criterion for significance, the increase in peak clad temperature has a
large detrimental effect with respect to ongoing work at Westinghouse 411 Fayettevilte Street o P. O. Box 1551
+ Raleigh, N. C. 27602 eaO90)00O8 ia08aS PDR
- DOCK 05000400 PDR
0 r
"I
Document Control Desk NLS-92-231 / Page 2
regarding fuel cladding burst and coolant flow channel blockage~.
As
- such, Westinghouse introduced a compensating change in the Small Break LOCA evaluation to reduce PCT.
This compensating change utilized axial core power distribution (i.e., Axial Offset) margin.
The analysis of record was performed with a +30% Axial Offset.
Using internal Westinghouse sensitivites, a
PCT credit of 75'F was obtained by reducing the analysis Axial Offset (for full-power operation) to +25%.
The new analysis basis is still very conservative compared to the Axial Offset limits imposed in the Core Operating Limits Report (COLR).
At full
- power, the COLR does not allow an Axial Offset above
+7%.
In summary, the change to the Small Break LOCA permanent PCT is 1981.1'F
+
17.2 75.0 1923.3'F The calculated performance of the SHNPP ECCS continues to meet the performance acceptance criteria specified in 10 CFR 50.46.
As stated in our February 19, 1992 letter, CPGL plans to reanalyze both the Large and Small Break LOCA events prior to Cycle 6 for SHNPP, to coincide with a change in nuclear fuel vendors.
Accordingly, these analyses of record will be approved and in place to support Refueling Outage No. 5, currently scheduled to begin in March 1994.
Questions regarding this matter may be referred to Mr. R.
W. Prunty at (919) 546-7318.
Yours very truly, MP D.
C. McCarthy Manager Nuclear Licensing Section SDC/sdc cc:
Mr. S.
D. Ebneter Mr. N. B. Le Mr. J.
E. Tedrow ET-NRC-92-3647, "Interim Report of a Deviation or Failure to Comply Pursuant to 10 CFR 21.21(a)(2),"
December 20, 1991 from S.
R. Tritch (W) to NRC.
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