ML071770136
| ML071770136 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 06/15/2007 |
| From: | Peifer M Indiana Michigan Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| AEP:NRC:7046-01 | |
| Download: ML071770136 (8) | |
Text
Indiana Michigan Power INDIANA Cook Nuclear Plant MICHIGAN One Cook Place Bridgman, Ml 49106 POWER' AEP~com Aunit of American Electric Power June 15, 2007 AEP:NRC:7046-01 10 CFR 50.46 Docket Nos.: 50-315 50-3 16 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop O-P1I- 17 Washington, DC 20555-0001 Donald C. Cook Nuclear Plant Unit 1 and Unit 2 THIRTY-DAY REPORT FOR LOSS-OF-COOLANT ACCIDENT EVALUATION MODEL CHANGES
References:
Nuclear Regulatory Commission (NRC) Document Control Desk, "Donald C.
Cook Nuclear Plant Units 1 and. 2, 10 CFR 50.46 Loss-of-Coolant Accident Reanalysis Schedule," submittal AEP:NRC:4046-01, Accession Number ML050040216, dated December 28, 2004.
- 2. Letter from J. N. Jensen, I&M, to NRC Document Control Desk, "Donald C. Cook Nuclear Plant Unit 1, Thirty-day Report of Loss-of-Coolant Accident Evaluation Model Changes," submittal AEP:NRC:5046, Accession Number ML051300368, dated April 29, 2005.
- 3. Letter from M. A. Peifer, I&M, to NRC Document Control Desk, "Donald C.
Cook Nuclear Plant Unit 1, Small Break Loss-of-Coolant Accident Evaluation Model Reanalysis," submittal AIEP:NRC:7046, Accession Number ML071000431, dated March 29, 2007.
Pursuant to 10 CFR 50.46, Indiana Michigan Power Company (I&M), the licensee for Donald C. Cook Nuclear Plant (CNP), is submitting a 30-day report on a loss-of-coolant accident (LOCA) model error resulting in a significant change in calculated peak fuel cladding temperature (PCT) for the CNP Unit I and Unit 2 large break LOCA (LBLOCA) analyses. A significant change is defined as a change or error identified in the model that results in a calculated PCT greater than 50 degrees Fahrenheit (OF) or a cumulation of changes and errors such that the sum of the absolute magnitudes of the respective temperature changes is greater than 50'F.
-ADC1
U. S. Nuclear Regulatory Commission AEP:NRC:7046-01 Page 2 Attachment J to this letter describes an assessment against the CNP Unit 1 and Unit 2 LBLOCA analyses of record. Attachment 2 provides the CNP Unit 1 and Unit 2 LBLOCA analyses of record PCT value and error assessments. Attachment 2 also demonstrates that the PCT value remains within the 2200'F PCT limit as required by 10 CFR 50.46(b)(1).
The overall change to the Unit 1 and Unit 2 LBLOCA analyses is classified as significant in accordance with 10 CFR 50.46(a)(3)(i). By Reference 1, I&M submitted a schedule for reanalysis of the Unit 1 and Unit 2 small break LOCA (SBLOCA) and the Unit 2 LBLOCA analyses of record.
By Reference 2, I&M submitted a schedule for reanalysis of the Unit 1 LBLOCA analysis of record.
By Reference 3, J&M met the schedule for reanalysis of the Unit 1 SBLOCA. I&M's current schedule for the remaining reanalyses is provided in Attachment 3.
Should you have any questions concerning this subject, please contact Ms. Susan D. Simpson, Regulatory Affairs Manager, at (269) 466-2428.
- Mark A. P er Site Support Services Vice President Attachments KAS/rdw c: J. L. Caldwell - NRC Region III K. D. Curry - AEP Ft. Wayne, w/o attachments J. T. King - MPSC, w/o attachments MDEQ - WHMD/RPMWS, w/o attachments NRC Resident Inspector P. S. Tam - NRC Washington, DC
ATTACHMENT 1 TO AEP:NRC:7046-01 ASSESSMENT AGAINST THE LOSS-OF-COOLANT ACCIDENT (LOCA)
ANALYSES OF RECORD Indiana Michigan Power Company's (I&M's) most recent annual 10 CFR 50.46 report for Donald C. Cook Nuclear Plant (CNP) has been submitted by Reference 1. By Reference 2, I&M reported an assessment against the Unit 1 large break loss-of-coolant accident (LBLOCA) analysis. New peak cladding temperature (PCT) assessments against the CNP Unit 1 and Unit 2 LBLOCA analyses of record are described below. The new assessments are reflected in the PCT accounting in Attachment 2.
Assessment Against the LBLOCA Analysis of Record LOCBART Pellet Volumetric Heat Generation Rate
Background
The LOCBART code has been modified to correct an inverted term in the calculation of the pellet volumetric heat generation rate. This change affects the steady-state and transient heat generation for all three types of rods modeled and could result in either an increase or decrease in PCT for a given calculation.
Affected Evaluation Models 1981 Westinghouse LBLOCA Evaluation Model with BASH Estimated Effect The impact on PCT was estimated using plant-specific LOCBART calculations. As indicated in the PCT accounting in Attachment 2, Table 1, for CNP Unit 1, the effect of the change to the LOCBART pellet volumetric heat generation rate is an 11I degree Fahrenheit ('F) penalty using the difference between the PCTs from LOCBART calculations with and without the error correction. For CNP Unit 2, a rebaseline calculation was performed to determine the limiting LOCBART calculation PCT prior to the error correction resulting in a penalty of 9'F. The LOCBART pellet volumetric heat generation rate assessment was then estimated for Unit 2 to be a 16'F penalty using the difference between the PCTs from LOCBART calculations with and without the error correction. The Unit 2 PCT accounting is in Attachment 2, Table 2.
Conclusion This transmittal satisfies the 30-day reporting requirement of 10 CFR 50.46(a)(3)(ii). demonstrates that the PCT value remains within the 2200TF PCT limit specified in 10 CFR 50.46(b)(1).
to AEP:NRC:7046-01 Page 2 References
- 1. Letter from J. N. Jensen, I&M, to U. S. Nuclear Regulatory Commission (NRC) Document Control Desk, "Donald C. Cook Nuclear Plant Units 1 and 2, Annual Report and Thirty-day Report of 10 CFR 50.46 Loss-of-Coolant Accident Evaluation Model Changes," Accession Number ML062340193, submittal AEP:NRC:6046, dated August 11, 2006.
- 2. Letter from J. N. Jensen, I&M, to NRC Document Control Desk, "Donald C. Cook
-Nuclear Plant Unit 1, Thirty-Day Report for Loss-of-Coolant Accident Evaluation Model Change," Accession Number ML063530324, submittal AEP :NRC :6046-01, dated December 7, 2006.
ATTACHMENT 2 TO AEP:NIRC:7046-O1 DONALD C. COOK NUCLEAR PLANT (CNP) UNIT 1 AND UNIT 2 LARGE BREAK LOSS-OF-COOLANT ACCIDENT (LOCA)
PEAK CLAD TEMPERATURE (PCT)
SUMMARY
to AEP:NRC:7046-O1 Pg Page I TABLE 1 CNP UNIT 1 LARGE BREAK LOCA Evaluation Model: BASH FQ =2.15 FAH = 1.55 SGTP = 15% Break Size: Cd =O. 4 Operational Parameters: RHR System Cross-Tie Valves Closed, 3250 MWt Reactor Power]
LICENSING BASIS Analysis-of-Record, December 2000 PCT = 2038OF MARGIN ALLOCATIONS (Delta PCT)
A. PREVIOUS 10 CFR 50.46 ASSESSMENTS
- 1. LOCBART Cladding Emissivity Errors -1 10F
- 2. Rebaseline Using PAD 4.0 +57 0F B. PLANNED 50.59 PLANT CHANGE EVALUATIONS dl. Reduced Containment Spray Temperature +23 0 F
- 2. 15XI15 Upgrade Fuel -59 0F C. New 10 CFR 50.46 ASSESSMENTS
- 1. LOCBART Pellet Volumetric Heat Generation Rate Error +1 10F D. OTHER 00 F E. LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =2059'F I. The 3250 MWt power level used in the reanalysis is acceptable because it bounds the Unit 1 3304 MWt steady state power limit in the operating license after adjusting for recapture of feedwater flow measurement and power calorimetric uncertainty.
to AEP:NRC:7046-O1 Pg Page 2 TABLE 2 CNP UNIT 2 LARGE BREAK LOCA Evaluation Model: BASH F0Q=2.335 FAN = 1.644 SGTP = 15% Break Size: Cd= 0.6 2
Operational Parameters: RHR System Cross-Tie Valves Closed, 3413 MWt Reactor Power LICENSING BASIS Analysis-of-Record, December 1995 "CT =2051 OF MARGIN ALLOCATIONS (Delta PCT)
A. PREVIOUS 10 CFR 50.46 ASSESSMENTS
- 1. ECCS double disk valve leakage +8 0F
- 2. BASH current limiting break size reanalysis to incorporate LOCBART +58 0 F spacer grid single phase beat transfer and LOCBART zirc-water oxidation error B. PLANNED 50.59 PLANT CHANGE EVALUATIONS
- 1. Cycle 13 ZIRLO Fuel Evaluation -50OF
- 2. Reduced Containment Spray Temperature +47 0F C. New 10 CFR 50.46 ASSESSMENTS
- 1. LOCBART Pellet Volumetric Heat Generation Rate Error +160F D. OTHER
- 1. Rebaseline of Limiting LOCBART Calculation +9 0F E. LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT = 2139'F
- 2. Power level used as basis for PCT acceptance is 3413 MWt due to the reanalysis (see Item A.2) to provide an integrated error effect on the limiting case. This reanalysis (Item A.2) is not considered the analysis-of-record due to the spectrum of break sizes not being reanalyzed to ensure that the limiting break size at 3413 MWt with the errors incorporated would not change. Thus, the analysis-of-record remains as the 1995 analysis at a power level of 3588 MWt. The difference between the limniting case PCT (205 10F) and the PCT from the reanalysis of that limiting break size at 3413 MWt is the 58'F being reported. The 3413 MWt power level used in the reanalysis is acceptable because it bounds the Unit 2 3468 MWt steady state power limit in the operating license after adjusting for recapture of feedwater flow measurement and power calorimetric uncertainty.
ATTACHMENT 3 TO AEP:NRC:7046-Ol REGULATORY COMMITMENTS The following table identifies those actions committed to by Indiana Michigan Power Company (I&M) in this document. Any other actions discussed in this submittal represent intended or planned actions by I&M. They are described to the Nuclear Regulatory Commission (NRC) for the NRCs information and are not regulatory commitments.
Commitment Date A new Unit 1 large break loss-of-coolant accident (LBLOCA) analysis December 2007 will be provided.
A new Unit 2 small break loss-of-coolant accident analysis of both the March 2009 safety injection cross-tie valves closed case and the safety injection cross-tie valves open case will be provided.
A new Unit 2 LBLOCA analysis will be provided. March 2009