ML20249C639

Rev 0 to Design Calculation 5922, NUREG 0619 RPV Feedwater Nozzle Crack Growth Reevaluation

ML20249C639
Person / Time
Site:	Fermi
Issue date:	11/26/1997
From:	Ching Ng, Mike Williams DETROIT EDISON CO.
To:
Shared Package
ML20249C636	List: ML20249C639 NRC-98-0095, Forwards Design Calculation 5922,rev 0, NUREG 0619 RPV Feedwater Nozzle Crack Growth Reevaluations, Per Telcon W/Nrc Staff
References
RTR-NUREG-0619, RTR-NUREG-619 5922, 5922-R, 5922-R00, NUDOCS 9806300468
Download: ML20249C639 (14)

Text

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Attachment to NRC-98-0095 l

l Attachment Design Calculation 5922 13 Pages 9006300460 990624 PDR ADOCK 05000341~

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DESIGN CALCULATION COVER SIIEET Page 1 of 13 PA R T 1: DESIGN CALCULA TION IDENTm!CA TION 1

A)

Design Calculation Number DC-5922 B)

Volume Number Vol. I C)

Revision 0 D) PIS Number B1113 E)

QA Level

[ ] Non-Q

[x] 1

[]1M F)

ASME Code Classification

[x]NA G) Certification Required

[] Yes

[x] No H)

Lead Discipline Mechanical / Civil I)

Incorporation Code F J)

Title NUREG 0619 RPV Feedwater Nozzle Crack Growth Reevaluation K)

Design Change Documents Incorporated (Number and Revision)

None L)

Design Calculations Superseded (Number and Revision)

{

None i

M) Revision Summary

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l Original issue.

. 1 PART2: PREPARATION, REVIEW, AND APPROVAL A)

Prepared By Michael S. Williams Sign

ML S, MN Date 10/31/97 B)

Checked By d.. /, AJg Sign C

4 Date ///2/,/77 C)

Verified By d, Y, Q 0

Sign a

c Date //[2db7 Ilf2-S gn Date

• Approve attached PE, if applicable Not Decommissioning Related DTC: TPMMES DSN: MES15001 Rev.1 Pl/l File: 1703.22 Approved: 012597 issued: 012897 DTC: TDPCAS O TDPELEO TDPINC O TDPMEC%

DSN:

Rev:

File: 1801 IP: 1 I

Paga 2

' Fermi 2 Power Plant 10/31/97 DC-5922 Vol. l Table of Contents l

Coversheet 1

Table of Contents 2

Introduction 3

Methodology / Summary of Results / References 4

Calculations-5-7 Appendix A - Yearly Event Summaries for 1991 to 1996 8-13 4

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' Fermi 2 Power Plant 10/30/97 j

DC-5922 Vol. I Computed by; #A.,Sk Checked by:

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==

Introduction:==

In the late 1970's, some BWR's developed serious cracks in their reactor vessels in the feedwater nozzle blend area. Studies by General Electric produced hardware modifications which were acceptable to NRC as a resolution of the problem (along with periodic inservice inspection). Fermi 2 installed the triple-sleeve sparger and the vessel was manufactured with unciad feedwater nozzles. However, we chose not to incorporate the recommended new feedwater low-flow controller because our existing I

controller was thought to be sufficient. In Generic Letter 81-11, the NRC stated that such a position is acceptable providing a plant-specific fracture mechanics analysis was performed which demonstrated that an initial assumed 1/4 inch nozzle crack would not grow to greater than one inch depth during the forty year life of the plant.

l In report GE-NE-523-22-0292, General Electric completed a plant specific feedwater

.i nozzle fracture mechanics assessment using recorded plant operating transient data for plant startups, shutdowns and scrams in the 1990-1991 time frame. Actual cyclic event I

counts were extracted from 1986-1990 operational data and used to project the thermal j_

duty out to forty years. Application of the 1989 ASME Code Section XI crack growth l ~'

rate relationship resulted in a crack depth of one inch after 38.3 years which failed to i

satisfy the requirement of less than one inch after 40 years.

In report GE-NE-523-22-0292, a total of 648 startup/ shutdown or scram events were projected for Fermi 2 over the 40-year design life of the plant. This projection was considered to be conservative because of the learning curve effects which are typically

. experienced during the initial years of operation. Therefore, we concluded that the requirement of less than one inch after 40 years was satisfied. In a letter dated December 8,1992, NRC required confirmation that a revised event projection would result in an acceptable crack growth estimate. The revised event projection was to be submitted for NRC review six months prior to the end of 12 operating years.

This calculation examines transient occurrences for the years 1991 to 1996 and revises the number of events predicted for the 40 year design life. The effect of the revised number of events on the results of GE-NE-523-22-0292 is also evaluated.

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' Fermi 2 Power Plant 10/30/97 DC-5922 Vol. I computed by: WhssJM'i Checked by:

Methodoloav:

For the years 1991 to 1996, the transient monitoring data collected as described in procedure MES 29 was reviewed and each startup/ shutdown, power reduction and scram was tabulated. Ten year totals were obtained by adding the number of eventa for years 1986 to 1990 tabulated in GE-NE-523-22-0292. Forty year projections were obtained by multiplying the ten year totals by four. Crack growth was estimated using Figure 6-1 of GE-NE-523-22-0292 which shows crack depth versus time.

Summary of results:

For the years 1986 to 1996, the plant experienced significant feedwater nozzle transients that can be represented by 46 startup/ shutdown events and 78 scram events for a ten year total of 124 events. Assuming the first ten years repeat four times, the forty year total is 496 events, which is considerably less than the 648 events used in GE-NE-523-22-0292. Using Figure 6-1 of GE-NE-523-22-0292, an initial. crack depth of

_]

.25 inch is estimated to grow to approximately.8 inch depth in forty years.

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References:

1. GE-NE-523-22-0292, revision 0, July 1992

2. KH1-0619-001, revision 0, October 1989 j

3. NEDE-21821-02, Supplement 2, August 1979 l

l

4. NUREG 0619, BWR Feedwater Nozzle and CRD Return Line Cracking

5. ASME Boiler and Pressure Vessel Code,Section XI,1989 Issue

6..NRC Generic Letter 81-11, February 20,1981

7. NRC Letter from T. Colburn to W. Orsor dated December 8,1992 l

8. UFSAR Section 5.2.1.20 i

9. MES 29, Documentation and Reporting of Operating Transients and Cycles l

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4 DC 5922 Vol.1 10-30-97 Page 5 Updated Thermal Cycle Count and Projections-NUREG %19 Feedwater Nozzle Crack Growth Analysis The transient monitoring data, collected as described in procedure MES 29, will be used to determine the thermal cycles experienced by the Feedwater Nozzh. However, for the feedwater nozzle, the following apply:

1. Since the scram transients used in report GE-NE-523-22-0292 are based on recorded data, there is no need to count scram events as startup, shutdown and scram but only aS scram.

2. Power reductions do not result in significant changes to feedwater temperature when reactor power remains above 50%. The GEC heat balance at 50% (before uprate) power indicates a feedwater temperature of 361*F [vrs 420 F @ 100% (before uprate) power]. Also, the rate of change of power reductions is slow. As such, only power reductions to below 50% power will be counted as scram events.

3. Since very little plant operation occurred in 1994, it was excluded from consideration.

The yearly transient monitoring data was reviewed for years 1991,1992,1993,1995 and 1996 and is tabulated on the following page. The detailed cycle count for each year is includedin Appendix A.

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F DC 5922 Vol. I l

10-30-97 Page 6 i

Year Startun/ Shutdown Scram Power Reductions to <50%

i 1991 4

2 2

1992 2

3 0

l 1993 2

6 1

l l

1995 3

3 6

i 1)96 6

2 1

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l Totals 17 16 10 i

i Previous totals from GE report GE-NE-523-22-0292:

I Startup/ Shutdown:

28

> For 1986,1987,1988,1989,1990 l

Scram:

53 l

Ten Year Totals:

l Startuh/ Shutdown 28+17=45

)

l Scram 53+16+10=79 l

)

Forty Year Projection (Conservative => First five years assumed to repeat)

~

Starup/ Shutdown 45 (4) = 180 Scram 79 (4) = 316 Total 496 The new cycle projection of 496 is plotted on Figure 6-1 of GE-NE-523-22-0292. The results show that a %" initial crack depth (as specified in NUREG-0619) reaches a depth of approximately 0.8" in forty years, which is less than the allowable depth of 1,0" in forty years. The acceptance criteria of NUREG 0619 are satisfied.

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DC 5922 Vol.1 10-30-97 f

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Appendix A i

Yearly Event Summaries 1

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i l-DC 5922 Vol.1 10-30-97 Page 9 Year 1991 Date Event Startun Shutdown Scram Comments l

2/2 Power Reduction to 58%

2/22 Power Reduction to 60%

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3/12 Scram 1

3/16 Power Reduction to 60%

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l 3/30 Shutdown 1

1 l

l' 6/14-16 Shutdown 2

2 l

l 6/23 Power Reduction I

to 33%

6/27 Scram 1

7/13 Power Reduction to 54%

i 9/25 Power Reduction 1

to 18%

i 10/19 Power Reduction to 79%

10/26 Power Reduction to 67%

11/5 Power Reduction to 79%

l 11/26 Power Reduction to 75%

11/29.-

Power Reduction to 73%

4 12/10 Shutdown 1

1 4

4 4

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DC 5922 Vol.1 l

10-30-97 Page 10

, Year 1992 Date Event Startun Shutdown Scram Comments 2/1 Power Reduction to 65%

3/14 Power Reduction to 70%

3/16 Scram 1

4/7 Shutdown 1

1 5/26 Power Reduction to ~ 60% (APRMS) 8/30 Power Reduction to 70%

9/12 Scram 1

11/18 Scram 1

i 11/28 Power Reduction to 60%

12/2 Power Reduction to 70%

12/5 Shutdown 1

1 12/25 Power Reduction to 70%

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DC 5922 Vol.1 10-30-97 Page 11 Year 1993 Date Event Startun Shutdown Scram Comments 1/22 Power Reduction Power > 50%

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2/6 Power Reduction to 66%

2/10 Shutdown 1

1 2/19 Scram 1

4/10 Shutdown '

1 1

4/20 Scram 1

from 510 psi 5/28 Power Reduction to 90%

7/3 Power Reduction to 65%

8/13 Scram 1

l 9/17-9/20 Scram 2

4 9/26 Power Reduction to 60%

10/9 Power Reduction 1

to 35%

12/14 Power Reduction to 65%

12/25 Scram 1

2 2

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DC 5922 Vol. I 10-30-97 Page 12 Year 1995 i

Date Event Startuo Shutdown Scram Comments 1/27 Shutdown 1

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2/1 Shutdown 1

1 2/14 Shutdown 1

1 3/14 Power Reduction 1

MTG offline 3/16 Power Reduction 1

MTG offline 3/26 Power Reduction 1

MTG offline t./0 Scram 1

1 4/12 Power Reduction 1

MTG offline 4/25 Scram 1

5/13 Power Reduction 1

to 46%

6/2 Scram 1

7/16 Power Reduction to 60%

10/13 Power Reduction to 65%

10/20 Power Reduction to 68%

11/3 Power Reduction to 65%

12/1 l'~

Power Reduction 1

to 35%

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g DC 5922 Vol.1 l

10-30-97 l

Page 13

, Year 1996

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Date Event Startuo Shutdown Scram Comments 1/20 Power Reduction to 56%

l 2/10 Power Reduction to 65%

I 3/27 Scram 1

4/18 Shutdown 1

1 j

4/24 Power Reduction to 69%

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5/4 Power Reduction to 64%

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5/9 Power Reduction to 64%

1 6/2 Power Reduction I

to 50%

i 6/29 Power Reduction to 63%

l 8/3 Power Reduction to 60%

9/8 Power Reduction to 63%

9/27 Shutdown 1

1 12/3 Shutdown 1

1 12/8 Shutdown 1

1 12/22 Shutdown 1

1 12/24..

Shutdown 1

1 12/28 Scram 1

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